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compare: Neur0toxine:d3029d09e7949f92254496b2100f42c33b70d77c
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No commits in common. "99b5b8c775e3a3b6d92c27f1e655c5b6078a7a1a" and "d3029d09e7949f92254496b2100f42c33b70d77c" have entirely different histories.
99b5b8c775 ... d3029d09e7

60 changed files with 904 additions and 15447 deletions
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15
Makefile
View File

@ -39,18 +39,3 @@ generate:
install_protobuf:
@go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
@go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
update_sshlib:
@rm -rf cryptolib && \
git clone https://go.googlesource.com/crypto cryptolib && \
rm -rf pkg/proto/ssh && \
mv cryptolib/ssh pkg/proto/ && \
mv cryptolib/internal/poly1305 pkg/proto/ssh/internal/ && \
find pkg/proto/ssh -type f -name '*.go' -exec sed -i 's?golang.org/x/crypto/ssh?github.com/Neur0toxine/sshpoke/pkg/proto/ssh?g' {} \; && \
find pkg/proto/ssh -type f -name '*.go' -exec sed -i 's?golang.org/x/crypto/internal/poly1305?github.com/Neur0toxine/sshpoke/pkg/proto/ssh/internal/poly1305?g' {} \; && \
find pkg/proto/ssh -type f -name '*_test.go' -delete && \
patch -p0 < patch/ssh_fakehost.patch && \
rm -rf pkg/proto/ssh/test && \
rm -rf pkg/proto/ssh/testdata && \
rm -rf cryptolib

9
go.mod
View File

@ -5,7 +5,6 @@ go 1.21.4
require (
github.com/docker/docker v24.0.7+incompatible
github.com/docker/go-connections v0.4.0
github.com/function61/gokit v0.0.0-20231117065306-355fe206d542
github.com/go-playground/validator/v10 v10.16.0
github.com/kevinburke/ssh_config v1.2.0
github.com/mitchellh/mapstructure v1.5.0
@ -14,9 +13,7 @@ require (
github.com/spf13/viper v1.17.0
go.uber.org/zap v1.26.0
golang.design/x/lockfree v0.0.1
golang.org/x/crypto v0.14.0
golang.org/x/sys v0.13.0
golang.org/x/term v0.13.0
golang.org/x/crypto v0.13.0
google.golang.org/grpc v1.58.2
google.golang.org/protobuf v1.31.0
)
@ -52,8 +49,8 @@ require (
go.uber.org/multierr v1.11.0 // indirect
golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
golang.org/x/mod v0.12.0 // indirect
golang.org/x/net v0.17.0 // indirect
golang.org/x/sync v0.3.0 // indirect
golang.org/x/net v0.15.0 // indirect
golang.org/x/sys v0.12.0 // indirect
golang.org/x/text v0.13.0 // indirect
golang.org/x/tools v0.13.0 // indirect
google.golang.org/genproto/googleapis/rpc v0.0.0-20230920204549-e6e6cdab5c13 // indirect

18
go.sum
View File

@ -77,8 +77,6 @@ github.com/frankban/quicktest v1.14.4 h1:g2rn0vABPOOXmZUj+vbmUp0lPoXEMuhTpIluN0X
github.com/frankban/quicktest v1.14.4/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4HY=
github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw=
github.com/function61/gokit v0.0.0-20231117065306-355fe206d542 h1:a9BTN+DOboRkVih0suT4zrRZ4zLGFpBtHPGNd+EQ4pI=
github.com/function61/gokit v0.0.0-20231117065306-355fe206d542/go.mod h1:sJY957+7ush4oj4ElOMhUFaFIriAFNAGYzVh2tFJNy0=
github.com/gabriel-vasile/mimetype v1.4.2 h1:w5qFW6JKBz9Y393Y4q372O9A7cUSequkh1Q7OhCmWKU=
github.com/gabriel-vasile/mimetype v1.4.2/go.mod h1:zApsH/mKG4w07erKIaJPFiX0Tsq9BFQgN3qGY5GnNgA=
github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
@ -257,8 +255,8 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
golang.org/x/crypto v0.13.0 h1:mvySKfSWJ+UKUii46M40LOvyWfN0s2U+46/jDd0e6Ck=
golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@ -328,8 +326,8 @@ golang.org/x/net v0.0.0-20201209123823-ac852fbbde11/go.mod h1:m0MpNAwzfU5UDzcl9v
golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
golang.org/x/net v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@ -387,11 +385,11 @@ golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7w
golang.org/x/sys v0.0.0-20210423185535-09eb48e85fd7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220908164124-27713097b956/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/term v0.13.0 h1:bb+I9cTfFazGW51MZqBVmZy7+JEJMouUHTUSKVQLBek=
golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
golang.org/x/term v0.12.0 h1:/ZfYdc3zq+q02Rv9vGqTeSItdzZTSNDmfTi0mBAuidU=
golang.org/x/term v0.12.0/go.mod h1:owVbMEjm3cBLCHdkQu9b1opXd4ETQWc3BhuQGKgXgvU=
golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

2
internal/docker/api.go
View File

@ -110,7 +110,7 @@ func (d *Docker) Listen() (chan dto.Event, error) {
"container.ip", converted.IP.String(),
"container.port", converted.Port,
"container.server", converted.Server,
"container.remote_host", converted.RemoteHost)
"container.prefix", converted.Prefix)
output <- newEvent
case err := <-errSource:
if errors.Is(err, context.Canceled) {

4
internal/docker/convert.go
View File

@ -17,7 +17,7 @@ type labelsConfig struct {
Network string `mapstructure:"sshpoke.network"`
Server string `mapstructure:"sshpoke.server"`
Port string `mapstructure:"sshpoke.port"`
RemoteHost string `mapstructure:"sshpoke.remote_host"`
Prefix string `mapstructure:"sshpoke.prefix"`
}
type boolStr string
@ -82,7 +82,7 @@ func dockerContainerToInternal(container types.Container) (result dto.Container,
IP: ip,
Port: uint16(port),
Server: labels.Server,
RemoteHost: labels.RemoteHost,
Prefix: labels.Prefix,
}, true
}

159
internal/server/driver/ssh/driver.go
View File

@ -2,53 +2,48 @@ package ssh
import (
"context"
"net"
"errors"
"fmt"
"os"
"path"
"strconv"
"strings"
"sync"
"github.com/Neur0toxine/sshpoke/internal/config"
"github.com/Neur0toxine/sshpoke/internal/server/driver/base"
"github.com/Neur0toxine/sshpoke/internal/server/driver/ssh/sshtun"
"github.com/Neur0toxine/sshpoke/internal/server/driver/ssh/types"
"github.com/Neur0toxine/sshpoke/internal/server/driver/util"
"github.com/Neur0toxine/sshpoke/internal/server/proto/sshtun"
"github.com/Neur0toxine/sshpoke/pkg/dto"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
"golang.org/x/crypto/ssh"
)
type SSH struct {
base.Base
params Params
auth []ssh.AuthMethod
conns map[string]conn
rw sync.RWMutex
sessions map[string]conn
keys []ssh.Signer
wg sync.WaitGroup
}
type conn struct {
ctx context.Context
cancel func()
container dto.Container
tun *sshtun.Tunnel
}
func New(ctx context.Context, name string, params config.DriverParams) (base.Driver, error) {
drv := &SSH{
Base: base.New(ctx, name),
conns: make(map[string]conn),
sessions: make(map[string]conn),
}
if err := util.UnmarshalParams(params, &drv.params); err != nil {
return nil, err
}
drv.populateFromSSHConfig()
drv.auth = drv.authenticators()
return drv, nil
if err := drv.parseKeys(); err != nil {
return nil, err
}
func (d *SSH) forward(val sshtun.Forward) conn {
tun := sshtun.New(d.params.Address, d.params.Auth.User, d.params.DisableRemoteHostResolve, val, d.auth, d.Log())
ctx, cancel := context.WithCancel(d.Context())
go tun.Connect(ctx, sshtun.StdoutPrinterSessionCallback(d.Log().With("ssh-output", val.Remote.String())))
return conn{ctx: ctx, cancel: cancel, tun: tun}
return drv, nil
}
func (d *SSH) populateFromSSHConfig() {
@ -75,43 +70,8 @@ func (d *SSH) populateFromSSHConfig() {
}
func (d *SSH) Handle(event dto.Event) error {
defer d.rw.Unlock()
d.rw.Lock()
switch event.Type {
case dto.EventStart:
conn := d.forward(sshtun.Forward{
Local: sshtun.AddrToEndpoint(net.JoinHostPort(event.Container.IP.String(), strconv.Itoa(int(event.Container.Port)))),
Remote: d.remoteEndpoint(event.Container.RemoteHost),
})
d.conns[event.Container.ID] = conn
d.wg.Add(1)
case dto.EventStop:
conn, found := d.conns[event.Container.ID]
if !found {
return nil
}
conn.cancel()
delete(d.conns, event.Container.ID)
d.wg.Done()
case dto.EventShutdown:
for id, conn := range d.conns {
conn.cancel()
delete(d.conns, id)
d.wg.Done()
}
}
return nil
}
func (d *SSH) remoteEndpoint(remoteHost string) sshtun.Endpoint {
port := int(d.params.ForwardPort)
if port == 0 {
port = 80
}
return sshtun.Endpoint{
Host: remoteHost,
Port: port,
}
// TODO: Implement event handling & connections management.
return errors.New("server handler is not implemented yet")
}
func (d *SSH) Driver() config.DriverType {
@ -119,38 +79,81 @@ func (d *SSH) Driver() config.DriverType {
}
func (d *SSH) WaitForShutdown() {
go d.Handle(dto.Event{Type: dto.EventShutdown})
d.wg.Wait()
}
func (d *SSH) authenticators() []ssh.AuthMethod {
auth := d.authenticator()
if auth == nil {
func (d *SSH) parseKeys() error {
if d.params.Auth.Type != types.AuthTypeKey {
return nil
}
return []ssh.AuthMethod{auth}
dir, err := d.params.Auth.Directory.Resolve(true)
if err != nil {
return fmt.Errorf("cannot parse keys: %s", err)
}
if d.params.Auth.Keyfile != "" {
key, err := parseKey(path.Join(dir, d.params.Auth.Keyfile))
if err != nil {
return err
}
d.keys = []ssh.Signer{key}
return nil
}
entries, err := os.ReadDir(dir)
if err != nil {
return fmt.Errorf("cannot read key directory: %s", err)
}
keys := []ssh.Signer{}
for _, entry := range entries {
if entry.IsDir() {
d.Log().Debugf("skipping '%s' because it's a directory", entry.Name())
continue
}
info, err := entry.Info()
if err != nil {
d.Log().Debugf("skipping '%s' because stat failed: %s", entry.Name(), err)
continue
}
if strings.HasSuffix(entry.Name(), ".pub") {
d.Log().Debugf("skipping '%s' because it's probably a public key", entry.Name())
continue
}
if entry.Name() == "config" {
d.Log().Debugf("skipping '%s' because it's probably a ssh-config file", entry.Name())
continue
}
if entry.Name() == "known_hosts" {
d.Log().Debugf(
"skipping '%s' because it's probably a list of hosts generated by OpenSSH", entry.Name())
continue
}
// this file is too small to be a private key
if info.Size() < 256 {
d.Log().Debugf("skipping '%s' because the file is smaller than 256 bytes", entry.Name())
continue
}
key, err := parseKey(path.Join(dir, entry.Name()))
if err != nil {
d.Log().Debugf("skipping '%s' because it's probably not a key: %s", entry.Name(), err)
continue
}
d.Log().Debugf("loading key '%s', type: %s", entry.Name(), key.PublicKey().Type())
keys = append(keys, key)
}
if len(keys) == 0 {
return errors.New("no keys in the provided directory")
}
d.keys = keys
return nil
}
func (d *SSH) authenticator() ssh.AuthMethod {
switch d.params.Auth.Type {
case types.AuthTypePasswordless:
return sshtun.AuthPassword("")
case types.AuthTypePassword:
return sshtun.AuthPassword(d.params.Auth.Password)
case types.AuthTypeKey:
if d.params.Auth.Keyfile != "" {
keyAuth, err := sshtun.AuthKeyFile(
types.SmartPath(path.Join(d.params.Auth.Directory.String(), d.params.Auth.Keyfile)))
func parseKey(keyFile string) (ssh.Signer, error) {
keyData, err := os.ReadFile(keyFile)
if err != nil {
return nil
return nil, err
}
return keyAuth
}
dirAuth, err := sshtun.AuthKeyDir(d.params.Auth.Directory)
key, err := ssh.ParsePrivateKey(keyData)
if err != nil {
return nil
return nil, err
}
return dirAuth
}
return nil
return key, nil
}

4
internal/server/driver/ssh/params.go
View File

@ -7,15 +7,13 @@ import (
type Params struct {
Address string `mapstructure:"address" validate:"required"`
DefaultHost *string `mapstructure:"default_host,omitempty"`
ForwardPort uint16 `mapstructure:"forward_port"`
Auth types.Auth `mapstructure:"auth"`
KeepAlive types.KeepAlive `mapstructure:"keepalive"`
Domain string `mapstructure:"domain"`
DomainProto string `mapstructure:"domain_proto"`
DomainExtractRegex string `mapstructure:"domain_extract_regex" validate:"validregexp"`
Mode types.DomainMode `mapstructure:"mode" validate:"required,oneof=single multi"`
DisableRemoteHostResolve bool `mapstructure:"disable_remote_host_resolve"`
Prefix bool `mapstructure:"prefix"`
}
func (p *Params) Validate() error {

91
internal/server/driver/ssh/sshtun/auth.go
View File

@ -1,91 +0,0 @@
package sshtun
import (
"errors"
"fmt"
"os"
"path"
"strings"
"github.com/Neur0toxine/sshpoke/internal/server/driver/ssh/types"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
func AuthKeyFile(keyFile types.SmartPath) (ssh.AuthMethod, error) {
key, err := readKey(keyFile)
if err != nil {
return nil, err
}
return ssh.PublicKeys(key), nil
}
func AuthKeyDir(keyDir types.SmartPath) (ssh.AuthMethod, error) {
keys, err := readKeys(keyDir)
if err != nil {
return nil, err
}
return ssh.PublicKeys(keys...), nil
}
func AuthPassword(password string) ssh.AuthMethod {
return ssh.Password(password)
}
func readKeys(keyDir types.SmartPath) ([]ssh.Signer, error) {
dir, err := keyDir.Resolve(true)
if err != nil {
return nil, fmt.Errorf("cannot parse keys: %s", err)
}
entries, err := os.ReadDir(dir)
if err != nil {
return nil, fmt.Errorf("cannot read key directory: %s", err)
}
keys := []ssh.Signer{}
for _, entry := range entries {
if entry.IsDir() {
continue
}
info, err := entry.Info()
if err != nil {
continue
}
if strings.HasSuffix(entry.Name(), ".pub") {
continue
}
if entry.Name() == "config" {
continue
}
if entry.Name() == "known_hosts" {
continue
}
// this file is too small to be a private key
if info.Size() < 256 {
continue
}
key, err := readKey(types.SmartPath(path.Join(dir, entry.Name())))
if err != nil {
continue
}
keys = append(keys, key)
}
if len(keys) == 0 {
return nil, errors.New("no keys in the provided directory")
}
return keys, nil
}
func readKey(keyFile types.SmartPath) (ssh.Signer, error) {
fileName, err := keyFile.Resolve(false)
if err != nil {
return nil, err
}
keyData, err := os.ReadFile(fileName)
if err != nil {
return nil, err
}
key, err := ssh.ParsePrivateKey(keyData)
if err != nil {
return nil, err
}
return key, nil
}

21
internal/server/driver/ssh/sshtun/config.go
View File

@ -1,21 +0,0 @@
package sshtun
import (
"bytes"
"os"
"github.com/Neur0toxine/sshpoke/internal/server/driver/ssh/types"
"github.com/kevinburke/ssh_config"
)
func parseSSHConfig(filePath types.SmartPath) (*ssh_config.Config, error) {
fileName, err := filePath.Resolve(false)
if err != nil {
return nil, err
}
file, err := os.ReadFile(fileName)
if err != nil {
return nil, err
}
return ssh_config.Decode(bytes.NewReader(file))
}

37
internal/server/driver/ssh/sshtun/forward.go
View File

@ -1,37 +0,0 @@
package sshtun
import (
"fmt"
"net"
"strconv"
"github.com/Neur0toxine/sshpoke/pkg/errtools"
)
type Forward struct {
// local service to be forwarded
Local Endpoint `json:"local"`
// remote forwarding port (on remote SSH server network)
Remote Endpoint `json:"remote"`
}
func AddrToEndpoint(address string) Endpoint {
host, port, err := net.SplitHostPort(address)
if err != nil && errtools.IsPortMissingErr(err) {
return Endpoint{Host: host, Port: 22}
}
portNum, err := strconv.Atoi(port)
if err != nil {
portNum = 22
}
return Endpoint{Host: host, Port: portNum}
}
type Endpoint struct {
Host string `json:"host"`
Port int `json:"port"`
}
func (endpoint *Endpoint) String() string {
return fmt.Sprintf("%s:%d", endpoint.Host, endpoint.Port)
}

21
internal/server/driver/ssh/sshtun/printer.go
View File

@ -1,21 +0,0 @@
package sshtun
import (
"bufio"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
"go.uber.org/zap"
)
func StdoutPrinterSessionCallback(log *zap.SugaredLogger) SessionCallback {
return func(session *ssh.Session) {
stdout, err := session.StdoutPipe()
if err != nil {
return
}
scan := bufio.NewScanner(stdout)
for scan.Scan() {
log.Debug(scan.Text())
}
}
}

217
internal/server/driver/ssh/sshtun/ssh.go
View File

@ -1,217 +0,0 @@
package sshtun
import (
"context"
"fmt"
"net"
"sync"
"sync/atomic"
"time"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
"github.com/function61/gokit/app/backoff"
"github.com/function61/gokit/io/bidipipe"
"go.uber.org/zap"
)
type SessionCallback func(*ssh.Session)
var NoopSessionCallback SessionCallback = func(*ssh.Session) {}
type Tunnel struct {
user string
address Endpoint
forward Forward
authMethods []ssh.AuthMethod
log *zap.SugaredLogger
connected atomic.Bool
fakeRemoteHost bool
}
func New(address, user string, fakeRemoteHost bool,
forward Forward, auth []ssh.AuthMethod, log *zap.SugaredLogger) *Tunnel {
return &Tunnel{
address: AddrToEndpoint(address),
user: user,
fakeRemoteHost: fakeRemoteHost,
forward: forward,
authMethods: auth,
log: log.With(zap.String("sshServer", address)),
}
}
func (c *Tunnel) Connect(ctx context.Context, sessionCb SessionCallback) {
if c.connected.Load() {
return
}
defer c.connected.Store(false)
backoffTime := backoff.ExponentialWithCappedMax(100*time.Millisecond, 5*time.Second)
for {
c.connected.Store(true)
err := c.connect(ctx, sessionCb)
if err != nil {
c.log.Error("connect error:", err)
}
select {
case <-ctx.Done():
return
default:
}
time.Sleep(backoffTime())
}
}
// connect once to the SSH server. if the connection breaks, we return error and the caller
// will try to re-connect
func (c *Tunnel) connect(ctx context.Context, sessionCb SessionCallback) error {
c.log.Debug("connecting")
sshConfig := &ssh.ClientConfig{
User: c.user,
Auth: c.authMethods,
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
}
var sshClient *ssh.Client
var errConnect error
sshClient, errConnect = dialSSH(ctx, c.address.String(), sshConfig)
if errConnect != nil {
return errConnect
}
defer sshClient.Close()
defer c.log.Debug("disconnecting")
c.log.Debug("connected")
listenerStopped := make(chan error)
sess, err := sshClient.NewSession()
if err != nil {
c.log.Errorf("session error: %s", err)
return err
}
defer sess.Close()
var wg sync.WaitGroup
if sessionCb == nil {
sessionCb = func(*ssh.Session) {}
}
wg.Add(2)
go func() {
defer wg.Done()
sessionCb(sess)
}()
reverseErr := make(chan error)
go func() {
defer wg.Done()
reverseErr <- c.reverseForwardOnePort(sshClient, listenerStopped)
}()
if err := <-reverseErr; err != nil {
return err
}
select {
case <-ctx.Done():
return nil
case listenerFirstErr := <-listenerStopped:
select {
case <-ctx.Done():
return nil
default:
return listenerFirstErr
}
}
}
// blocking flow: calls Listen() on the SSH connection, and if succeeds returns non-nil error
//
// nonblocking flow: if Accept() call fails, stops goroutine and returns error on ch listenerStopped
func (c *Tunnel) reverseForwardOnePort(sshClient *ssh.Client, listenerStopped chan<- error) error {
var (
listener net.Listener
err error
)
if c.fakeRemoteHost {
listener, err = sshClient.ListenTCP(&net.TCPAddr{
IP: c.ipFromAddr(sshClient.Conn.RemoteAddr()),
Port: c.forward.Remote.Port,
}, c.forward.Remote.Host)
} else {
listener, err = sshClient.Listen("tcp", c.forward.Remote.String())
}
if err != nil {
return err
}
go func() {
defer listener.Close()
c.log.Debugf("forwarding %s <- %s", c.forward.Local.String(), c.forward.Remote.String())
for {
client, err := listener.Accept()
if err != nil {
listenerStopped <- fmt.Errorf("error on Accept(): %w", err)
return
}
go handleReverseForwardConn(client, c.forward, c.log)
}
}()
return nil
}
func (c *Tunnel) ipFromAddr(addr net.Addr) net.IP {
host, _, _ := net.SplitHostPort(addr.String())
return net.ParseIP(host)
}
func handleReverseForwardConn(client net.Conn, forward Forward, log *zap.SugaredLogger) {
defer client.Close()
log.Debugf("%s connected", client.RemoteAddr())
defer log.Debug("closed")
remote, err := net.Dial("tcp", forward.Local.String())
if err != nil {
log.Errorf("dial INTO local service error: %s", err.Error())
return
}
// pipe data in both directions:
// - client => remote
// - remote => client
//
// - in effect, we act as a proxy between the reverse tunnel's client and locally-dialed
// remote endpoint.
// - the "client" and "remote" strings we give Pipe() is just for error&log messages
// - this blocks until either of the parties' socket closes (or breaks)
if err := bidipipe.Pipe(
bidipipe.WithName("client", client),
bidipipe.WithName("remote", remote),
); err != nil {
log.Error(err)
}
}
func dialSSH(ctx context.Context, addr string, sshConfig *ssh.ClientConfig) (*ssh.Client, error) {
dialer := net.Dialer{
Timeout: 10 * time.Second,
}
conn, err := dialer.DialContext(ctx, "tcp", addr)
if err != nil {
return nil, err
}
clConn, newChan, reqChan, err := ssh.NewClientConn(conn, addr, sshConfig)
if err != nil {
return nil, err
}
return ssh.NewClient(clConn, newChan, reqChan), nil
}

4
internal/server/driver/ssh/types/auth.go
View File

@ -62,10 +62,6 @@ func (k SmartPath) Resolve(shouldBeDirectory bool) (result string, err error) {
return
}
func (k SmartPath) String() string {
return string(k)
}
func (a Auth) Validate() error {
if a.Type == AuthTypePassword && a.Password == "" {
return fmt.Errorf("password must be provided for authentication type '%s'", AuthTypePassword)

249
internal/server/proto/sshtun/tunnel.go Normal file
View File

@ -0,0 +1,249 @@
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
package sshtun
import (
"context"
"fmt"
"io"
"net"
"sync"
"sync/atomic"
"time"
"golang.org/x/crypto/ssh"
)
type TunnelMode uint8
func (t TunnelMode) String() string {
switch t {
case TunnelForward:
return "->"
case TunnelReverse:
return "<-"
default:
return "<?>"
}
}
const (
TunnelForward TunnelMode = iota
TunnelReverse
)
type logger interface {
Printf(string, ...interface{})
}
type Tunnel struct {
Auth []ssh.AuthMethod
HostKeys ssh.HostKeyCallback
Mode TunnelMode
User string
HostAddr string
BindAddr string
DialAddr string
RetryInterval time.Duration
KeepAlive KeepAliveConfig
Logger logger
}
type KeepAliveConfig struct {
// Interval is the amount of time in seconds to wait before the
// Tunnel client will send a keep-alive message to ensure some minimum
// traffic on the SSH connection.
Interval uint
// CountMax is the maximum number of consecutive failed responses to
// keep-alive messages the client is willing to tolerate before considering
// the SSH connection as dead.
CountMax uint
}
func (t Tunnel) String() string {
var left, right string
switch t.Mode {
case TunnelForward:
left, right = t.BindAddr, t.DialAddr
case TunnelReverse:
left, right = t.DialAddr, t.BindAddr
}
return fmt.Sprintf("%s@%s | %s %s %s", t.User, t.HostAddr, left, t.Mode, right)
}
func (t Tunnel) Bind(ctx context.Context, wg *sync.WaitGroup) {
defer wg.Done()
for {
var once sync.Once // Only print errors once per session
func() {
// Connect to the server host via SSH.
cl, err := ssh.Dial("tcp", t.HostAddr, &ssh.ClientConfig{
User: t.User,
Auth: t.Auth,
HostKeyCallback: t.HostKeys,
Timeout: 5 * time.Second,
})
if err != nil {
once.Do(func() { t.Logger.Printf("(%v) SSH dial error: %v", t, err) })
return
}
wg.Add(1)
go t.keepAliveMonitor(&once, wg, cl)
defer cl.Close()
// Attempt to bind to the inbound socket.
var ln net.Listener
switch t.Mode {
case TunnelForward:
ln, err = net.Listen("tcp", t.BindAddr)
case TunnelReverse:
ln, err = cl.Listen("tcp", t.BindAddr)
}
if err != nil {
once.Do(func() { t.Logger.Printf("(%v) bind error: %v", t, err) })
return
}
// The socket is bound. Make sure we close it eventually.
bindCtx, cancel := context.WithCancel(ctx)
defer cancel()
go func() {
cl.Wait()
cancel()
}()
go func() {
<-bindCtx.Done()
once.Do(func() {}) // Suppress future errors
ln.Close()
}()
t.Logger.Printf("(%v) bound Tunnel", t)
defer t.Logger.Printf("(%v) collapsed Tunnel", t)
// Accept all incoming connections.
for {
cn1, err := ln.Accept()
if err != nil {
once.Do(func() { t.Logger.Printf("(%v) accept error: %v", t, err) })
return
}
wg.Add(1)
go t.dialTunnel(bindCtx, wg, cl, cn1)
}
}()
select {
case <-ctx.Done():
return
case <-time.After(t.RetryInterval):
t.Logger.Printf("(%v) retrying...", t)
}
}
}
func (t Tunnel) dialTunnel(ctx context.Context, wg *sync.WaitGroup, client *ssh.Client, cn1 net.Conn) {
defer wg.Done()
// The inbound connection is established. Make sure we close it eventually.
connCtx, cancel := context.WithCancel(ctx)
defer cancel()
go func() {
<-connCtx.Done()
cn1.Close()
}()
// Establish the outbound connection.
var cn2 net.Conn
var err error
switch t.Mode {
case TunnelForward:
cn2, err = client.Dial("tcp", t.DialAddr)
case TunnelReverse:
cn2, err = net.Dial("tcp", t.DialAddr)
}
if err != nil {
t.Logger.Printf("(%v) dial error: %v", t, err)
return
}
go func() {
<-connCtx.Done()
cn2.Close()
}()
t.Logger.Printf("(%v) connection established", t)
defer t.Logger.Printf("(%v) connection closed", t)
// Copy bytes from one connection to the other until one side closes.
var once sync.Once
var wg2 sync.WaitGroup
wg2.Add(2)
go func() {
defer wg2.Done()
defer cancel()
if _, err := io.Copy(cn1, cn2); err != nil {
once.Do(func() { t.Logger.Printf("(%v) connection error: %v", t, err) })
}
once.Do(func() {}) // Suppress future errors
}()
go func() {
defer wg2.Done()
defer cancel()
if _, err := io.Copy(cn2, cn1); err != nil {
once.Do(func() { t.Logger.Printf("(%v) connection error: %v", t, err) })
}
once.Do(func() {}) // Suppress future errors
}()
wg2.Wait()
}
// keepAliveMonitor periodically sends messages to invoke a response.
// If the server does not respond after some period of time,
// assume that the underlying net.Conn abruptly died.
func (t Tunnel) keepAliveMonitor(once *sync.Once, wg *sync.WaitGroup, client *ssh.Client) {
defer wg.Done()
if t.KeepAlive.Interval == 0 || t.KeepAlive.CountMax == 0 {
return
}
// Detect when the SSH connection is closed.
wait := make(chan error, 1)
wg.Add(1)
go func() {
defer wg.Done()
wait <- client.Wait()
}()
// Repeatedly check if the remote server is still alive.
var aliveCount int32
ticker := time.NewTicker(time.Duration(t.KeepAlive.Interval) * time.Second)
defer ticker.Stop()
for {
select {
case err := <-wait:
if err != nil && err != io.EOF {
once.Do(func() { t.Logger.Printf("(%v) SSH error: %v", t, err) })
}
return
case <-ticker.C:
if n := atomic.AddInt32(&aliveCount, 1); n > int32(t.KeepAlive.CountMax) {
once.Do(func() { t.Logger.Printf("(%v) SSH keep-alive termination", t) })
client.Close()
return
}
}
wg.Add(1)
go func() {
defer wg.Done()
_, _, err := client.SendRequest("keepalive@openssh.com", true, nil)
if err == nil {
atomic.StoreInt32(&aliveCount, 0)
}
}()
}
}

509
internal/server/proto/sshtun/tunnel_test.go Normal file
View File

@ -0,0 +1,509 @@
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
package sshtun
import (
"bytes"
"context"
"crypto/md5"
"crypto/rsa"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"math/rand"
"net"
"reflect"
"strconv"
"sync"
"testing"
"time"
"golang.org/x/crypto/ssh"
)
type testLogger struct {
*testing.T // Already has Fatalf method
}
func (t testLogger) Printf(f string, x ...interface{}) { t.Logf(f, x...) }
func TestTunnel(t *testing.T) {
rootWG := new(sync.WaitGroup)
defer rootWG.Wait()
rootCtx, cancelAll := context.WithCancel(context.Background())
defer cancelAll()
// Open all of the TCP sockets needed for the test.
tcpLn0 := openListener(t) // Start of the chain
tcpLn1 := openListener(t) // Mid-point of the chain
tcpLn2 := openListener(t) // End of the chain
srvLn0 := openListener(t) // Socket for SSH server in reverse Mode
srvLn1 := openListener(t) // Socket for SSH server in forward Mode
tcpLn0.Close() // To be later binded by the reverse Tunnel
tcpLn1.Close() // To be later binded by the forward Tunnel
go closeWhenDone(rootCtx, tcpLn2)
go closeWhenDone(rootCtx, srvLn0)
go closeWhenDone(rootCtx, srvLn1)
// Generate keys for both the servers and clients.
clientPriv0, clientPub0 := generateKeys(t)
clientPriv1, clientPub1 := generateKeys(t)
serverPriv0, serverPub0 := generateKeys(t)
serverPriv1, serverPub1 := generateKeys(t)
// Start the SSH servers.
rootWG.Add(2)
go func() {
defer rootWG.Done()
runServer(t, rootCtx, srvLn0, serverPriv0, clientPub0, clientPub1)
}()
go func() {
defer rootWG.Done()
runServer(t, rootCtx, srvLn1, serverPriv1, clientPub0, clientPub1)
}()
wg := new(sync.WaitGroup)
defer wg.Wait()
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
// Create the Tunnel configurations.
tn0 := Tunnel{
Auth: []ssh.AuthMethod{ssh.PublicKeys(clientPriv0)},
HostKeys: ssh.FixedHostKey(serverPub0),
Mode: TunnelReverse, // Reverse Tunnel
User: "user0",
HostAddr: srvLn0.Addr().String(),
BindAddr: tcpLn0.Addr().String(),
DialAddr: tcpLn1.Addr().String(),
Logger: testLogger{t},
}
tn1 := Tunnel{
Auth: []ssh.AuthMethod{ssh.PublicKeys(clientPriv1)},
HostKeys: ssh.FixedHostKey(serverPub1),
Mode: TunnelForward, // Forward Tunnel
User: "user1",
HostAddr: srvLn1.Addr().String(),
BindAddr: tcpLn1.Addr().String(),
DialAddr: tcpLn2.Addr().String(),
Logger: testLogger{t},
}
// Start the SSH client tunnels.
wg.Add(2)
go tn0.Bind(ctx, wg)
go tn1.Bind(ctx, wg)
t.Log("test started")
done := make(chan bool, 10)
// Start all the transmitters.
for i := 0; i < cap(done); i++ {
i := i
go func() {
for {
rnd := rand.New(rand.NewSource(int64(i)))
hash := md5.New()
size := uint32((1 << 10) + rnd.Intn(1<<20))
buf4 := make([]byte, 4)
binary.LittleEndian.PutUint32(buf4, size)
cnStart, err := net.Dial("tcp", tcpLn0.Addr().String())
if err != nil {
time.Sleep(10 * time.Millisecond)
continue
}
defer cnStart.Close()
if _, err := cnStart.Write(buf4); err != nil {
t.Errorf("write size error: %v", err)
break
}
r := io.LimitReader(rnd, int64(size))
w := io.MultiWriter(cnStart, hash)
if _, err := io.Copy(w, r); err != nil {
t.Errorf("copy error: %v", err)
break
}
if _, err := cnStart.Write(hash.Sum(nil)); err != nil {
t.Errorf("write hash error: %v", err)
break
}
if err := cnStart.Close(); err != nil {
t.Errorf("close error: %v", err)
break
}
break
}
}()
}
// Start all the receivers.
for i := 0; i < cap(done); i++ {
go func() {
for {
hash := md5.New()
buf4 := make([]byte, 4)
cnEnd, err := tcpLn2.Accept()
if err != nil {
time.Sleep(10 * time.Millisecond)
continue
}
defer cnEnd.Close()
if _, err := io.ReadFull(cnEnd, buf4); err != nil {
t.Errorf("read size error: %v", err)
break
}
size := binary.LittleEndian.Uint32(buf4)
r := io.LimitReader(cnEnd, int64(size))
if _, err := io.Copy(hash, r); err != nil {
t.Errorf("copy error: %v", err)
break
}
wantHash, err := ioutil.ReadAll(cnEnd)
if err != nil {
t.Errorf("read hash error: %v", err)
break
}
if err := cnEnd.Close(); err != nil {
t.Errorf("close error: %v", err)
break
}
if gotHash := hash.Sum(nil); !bytes.Equal(gotHash, wantHash) {
t.Errorf("hash mismatch:\ngot %x\nwant %x", gotHash, wantHash)
}
break
}
done <- true
}()
}
for i := 0; i < cap(done); i++ {
select {
case <-done:
case <-time.After(10 * time.Second):
t.Errorf("timed out: %d remaining", cap(done)-i)
return
}
}
t.Log("test complete")
}
// generateKeys generates a random pair of SSH private and public keys.
func generateKeys(t *testing.T) (priv ssh.Signer, pub ssh.PublicKey) {
rnd := rand.New(rand.NewSource(time.Now().Unix()))
rsaKey, err := rsa.GenerateKey(rnd, 1024)
if err != nil {
t.Fatalf("unable to generate RSA key pair: %v", err)
}
priv, err = ssh.NewSignerFromKey(rsaKey)
if err != nil {
t.Fatalf("unable to generate signer: %v", err)
}
pub, err = ssh.NewPublicKey(&rsaKey.PublicKey)
if err != nil {
t.Fatalf("unable to generate public key: %v", err)
}
return priv, pub
}
func openListener(t *testing.T) net.Listener {
ln, err := net.Listen("tcp", ":0")
if err != nil {
t.Fatalf("listen error: %v", err)
}
return ln
}
// runServer starts an SSH server capable of handling forward and reverse
// TCP tunnels. This function blocks for the entire duration that the
// server is running and can be stopped by canceling the context.
//
// The server listens on the provided Listener and will present to clients
// a certificate from serverKey and will only accept users that match
// the provided clientKeys. Only users of the name "User%d" are allowed where
// the ID number is the index for the specified client key provided.
func runServer(t *testing.T, ctx context.Context, ln net.Listener, serverKey ssh.Signer, clientKeys ...ssh.PublicKey) {
wg := new(sync.WaitGroup)
defer wg.Wait()
// Generate SSH server configuration.
conf := ssh.ServerConfig{
PublicKeyCallback: func(c ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
var uid int
_, err := fmt.Sscanf(c.User(), "User%d", &uid)
if err != nil || uid >= len(clientKeys) || !bytes.Equal(clientKeys[uid].Marshal(), pubKey.Marshal()) {
return nil, fmt.Errorf("unknown public key for %q", c.User())
}
return nil, nil
},
}
conf.AddHostKey(serverKey)
// Handle every SSH client connection.
for {
tcpCn, err := ln.Accept()
if err != nil {
if !isDone(ctx) {
t.Errorf("accept error: %v", err)
}
return
}
wg.Add(1)
go handleServerConn(t, ctx, wg, tcpCn, &conf)
}
}
// handleServerConn handles a single SSH connection.
func handleServerConn(t *testing.T, ctx context.Context, wg *sync.WaitGroup, tcpCn net.Conn, conf *ssh.ServerConfig) {
defer wg.Done()
go closeWhenDone(ctx, tcpCn)
defer tcpCn.Close()
sshCn, chans, reqs, err := ssh.NewServerConn(tcpCn, conf)
if err != nil {
t.Errorf("new connection error: %v", err)
return
}
go closeWhenDone(ctx, sshCn)
defer sshCn.Close()
wg.Add(1)
go handleServerChannels(t, ctx, wg, sshCn, chans)
wg.Add(1)
go handleServerRequests(t, ctx, wg, sshCn, reqs)
if err := sshCn.Wait(); err != nil && err != io.EOF && !isDone(ctx) {
t.Errorf("connection error: %v", err)
}
}
// handleServerChannels handles new channels on a SSH connection.
// The client initiates a new channel when forwarding a TCP dial.
func handleServerChannels(t *testing.T, ctx context.Context, wg *sync.WaitGroup, sshCn ssh.Conn, chans <-chan ssh.NewChannel) {
defer wg.Done()
for nc := range chans {
if nc.ChannelType() != "direct-tcpip" {
nc.Reject(ssh.UnknownChannelType, "not implemented")
continue
}
var args struct {
DstHost string
DstPort uint32
SrcHost string
SrcPort uint32
}
if !unmarshalData(nc.ExtraData(), &args) {
nc.Reject(ssh.Prohibited, "invalid request")
continue
}
// Open a connection for both sides.
cn, err := net.Dial("tcp", net.JoinHostPort(args.DstHost, strconv.Itoa(int(args.DstPort))))
if err != nil {
nc.Reject(ssh.ConnectionFailed, err.Error())
continue
}
ch, reqs, err := nc.Accept()
if err != nil {
t.Errorf("accept channel error: %v", err)
cn.Close()
continue
}
go ssh.DiscardRequests(reqs)
wg.Add(1)
go bidirCopyAndClose(t, ctx, wg, cn, ch)
}
}
// handleServerRequests handles new requests on a SSH connection.
// The client initiates a new request for binding a local TCP socket.
func handleServerRequests(t *testing.T, ctx context.Context, wg *sync.WaitGroup, sshCn ssh.Conn, reqs <-chan *ssh.Request) {
defer wg.Done()
for r := range reqs {
if !r.WantReply {
continue
}
if r.Type != "tcpip-forward" {
r.Reply(false, nil)
continue
}
var args struct {
Host string
Port uint32
}
if !unmarshalData(r.Payload, &args) {
r.Reply(false, nil)
continue
}
ln, err := net.Listen("tcp", net.JoinHostPort(args.Host, strconv.Itoa(int(args.Port))))
if err != nil {
r.Reply(false, nil)
continue
}
var resp struct{ Port uint32 }
_, resp.Port = splitHostPort(ln.Addr().String())
if err := r.Reply(true, marshalData(resp)); err != nil {
t.Errorf("request reply error: %v", err)
ln.Close()
continue
}
wg.Add(1)
go handleLocalListener(t, ctx, wg, sshCn, ln, args.Host)
}
}
// handleLocalListener handles every new connection on the provided socket.
// All local connections will be forwarded to the client via a new channel.
func handleLocalListener(t *testing.T, ctx context.Context, wg *sync.WaitGroup, sshCn ssh.Conn, ln net.Listener, host string) {
defer wg.Done()
go closeWhenDone(ctx, ln)
defer ln.Close()
for {
// Open a connection for both sides.
cn, err := ln.Accept()
if err != nil {
if !isDone(ctx) {
t.Errorf("accept error: %v", err)
}
return
}
var args struct {
DstHost string
DstPort uint32
SrcHost string
SrcPort uint32
}
args.DstHost, args.DstPort = splitHostPort(cn.LocalAddr().String())
args.SrcHost, args.SrcPort = splitHostPort(cn.RemoteAddr().String())
args.DstHost = host // This must match on client side!
ch, reqs, err := sshCn.OpenChannel("forwarded-tcpip", marshalData(args))
if err != nil {
t.Errorf("open channel error: %v", err)
cn.Close()
continue
}
go ssh.DiscardRequests(reqs)
wg.Add(1)
go bidirCopyAndClose(t, ctx, wg, cn, ch)
}
}
// bidirCopyAndClose performs a bi-directional copy on both connections
// until either side closes the connection or the context is canceled.
// This will close both connections before returning.
func bidirCopyAndClose(t *testing.T, ctx context.Context, wg *sync.WaitGroup, c1, c2 io.ReadWriteCloser) {
defer wg.Done()
go closeWhenDone(ctx, c1)
go closeWhenDone(ctx, c2)
defer c1.Close()
defer c2.Close()
errc := make(chan error, 2)
go func() {
_, err := io.Copy(c1, c2)
errc <- err
}()
go func() {
_, err := io.Copy(c2, c1)
errc <- err
}()
if err := <-errc; err != nil && err != io.EOF && !isDone(ctx) {
t.Errorf("copy error: %v", err)
}
}
// unmarshalData parses b into s, where s is a pointer to a struct.
// Only unexported fields of type uint32 or string are allowed.
func unmarshalData(b []byte, s interface{}) bool {
v := reflect.ValueOf(s)
if !v.IsValid() || v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
panic("destination must be pointer to struct")
}
v = v.Elem()
for i := 0; i < v.NumField(); i++ {
switch v.Type().Field(i).Type.Kind() {
case reflect.Uint32:
if len(b) < 4 {
return false
}
v.Field(i).Set(reflect.ValueOf(binary.BigEndian.Uint32(b)))
b = b[4:]
case reflect.String:
if len(b) < 4 {
return false
}
n := binary.BigEndian.Uint32(b)
b = b[4:]
if uint64(len(b)) < uint64(n) {
return false
}
v.Field(i).Set(reflect.ValueOf(string(b[:n])))
b = b[n:]
default:
panic("invalid field type: " + v.Type().Field(i).Type.String())
}
}
return len(b) == 0
}
// marshalData serializes s into b, where s is a struct (or a pointer to one).
// Only unexported fields of type uint32 or string are allowed.
func marshalData(s interface{}) (b []byte) {
v := reflect.ValueOf(s)
if v.IsValid() && v.Kind() == reflect.Ptr {
v = v.Elem()
}
if !v.IsValid() || v.Kind() != reflect.Struct {
panic("source must be a struct")
}
var arr32 [4]byte
for i := 0; i < v.NumField(); i++ {
switch v.Type().Field(i).Type.Kind() {
case reflect.Uint32:
binary.BigEndian.PutUint32(arr32[:], uint32(v.Field(i).Uint()))
b = append(b, arr32[:]...)
case reflect.String:
binary.BigEndian.PutUint32(arr32[:], uint32(v.Field(i).Len()))
b = append(b, arr32[:]...)
b = append(b, v.Field(i).String()...)
default:
panic("invalid field type: " + v.Type().Field(i).Type.String())
}
}
return b
}
func splitHostPort(s string) (string, uint32) {
host, port, _ := net.SplitHostPort(s)
p, _ := strconv.Atoi(port)
return host, uint32(p)
}
func closeWhenDone(ctx context.Context, c io.Closer) {
<-ctx.Done()
c.Close()
}
func isDone(ctx context.Context) bool {
select {
case <-ctx.Done():
return true
default:
return false
}
}

23
patch/ssh_fakehost.patch
View File

@ -1,23 +0,0 @@
--- pkg/proto/ssh/tcpip.go 2023-11-18 21:39:15.394837005 +0300
+++ pkg/proto/ssh/tcpip.go 2023-11-18 21:38:25.706173351 +0300
@@ -101,14 +101,18 @@
// ListenTCP requests the remote peer open a listening socket
// on laddr. Incoming connections will be available by calling
// Accept on the returned net.Listener.
-func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) {
+func (c *Client) ListenTCP(laddr *net.TCPAddr, fakeHost ...string) (net.Listener, error) {
c.handleForwardsOnce.Do(c.handleForwards)
if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) {
return c.autoPortListenWorkaround(laddr)
}
+ host := laddr.IP.String()
+ if len(fakeHost) > 0 {
+ host = fakeHost[0]
+ }
m := channelForwardMsg{
- laddr.IP.String(),
+ host,
uint32(laddr.Port),
}
// send message

4
pkg/convert/convert.go
View File

@ -16,7 +16,7 @@ func MessageToAppEvent(event *pb.EventMessage) dto.Event {
IP: net.ParseIP(event.GetContainer().GetIp()),
Port: uint16(event.GetContainer().GetPort()),
Server: event.GetContainer().GetServer(),
RemoteHost: event.GetContainer().GetRemoteHost(),
Prefix: event.GetContainer().GetPrefix(),
Domain: event.GetContainer().GetDomain(),
},
}
@ -31,7 +31,7 @@ func AppEventToMessage(event dto.Event) *pb.EventMessage {
Ip: event.Container.IP.String(),
Port: uint32(event.Container.Port),
Server: event.Container.Server,
RemoteHost: event.Container.RemoteHost,
Prefix: event.Container.Prefix,
Domain: event.Container.Domain,
},
}

2
pkg/dto/models.go
View File

@ -41,6 +41,6 @@ type Container struct {
IP net.IP `json:"ip"`
Port uint16 `json:"port"`
Server string `json:"-"`
RemoteHost string `json:"remote_host"`
Prefix string `json:"prefix"`
Domain string `json:"domain"`
}

18
pkg/errtools/is_port_missing_err.go
View File

@ -1,18 +0,0 @@
package errtools
import (
"errors"
"strings"
)
func IsPortMissingErr(err error) bool {
for {
if err == nil {
return false
}
if strings.Contains(err.Error(), "missing port in address") {
return true
}
err = errors.Unwrap(err)
}
}

9
pkg/plugin/client.go
View File

@ -9,7 +9,6 @@ import (
"github.com/Neur0toxine/sshpoke/pkg/convert"
"github.com/Neur0toxine/sshpoke/pkg/dto"
"github.com/Neur0toxine/sshpoke/pkg/errtools"
"github.com/Neur0toxine/sshpoke/pkg/plugin/pb"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials/insecure"
@ -58,12 +57,12 @@ func normalizeAddr(addr string) string {
if strings.HasPrefix(addr, "grpc://") {
addr = addr[7:]
}
_, _, err := net.SplitHostPort(addr)
if err != nil && errtools.IsPortMissingErr(err) {
addr = net.JoinHostPort(addr, strconv.Itoa(DefaultPort))
host, port, err := net.SplitHostPort(addr)
if err != nil && err.Error() == "missing port in address" {
host, port, err = net.SplitHostPort(addr + ":" + strconv.Itoa(DefaultPort))
}
if err != nil {
return ""
}
return addr
return host + ":" + port
}

2
pkg/plugin/pb/pb.proto
View File

@ -23,7 +23,7 @@ message Container {
string ip = 3;
uint32 port = 4;
string server = 5;
string remote_host = 6;
string prefix = 6;
string domain = 7;
}

854
pkg/proto/ssh/agent/client.go
View File

@ -1,854 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package agent implements the ssh-agent protocol, and provides both
// a client and a server. The client can talk to a standard ssh-agent
// that uses UNIX sockets, and one could implement an alternative
// ssh-agent process using the sample server.
//
// References:
//
// [PROTOCOL.agent]: https://tools.ietf.org/html/draft-miller-ssh-agent-00
package agent // import "github.com/Neur0toxine/sshpoke/pkg/proto/ssh/agent"
import (
"bytes"
"crypto/dsa"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rsa"
"encoding/base64"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"sync"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
// SignatureFlags represent additional flags that can be passed to the signature
// requests an defined in [PROTOCOL.agent] section 4.5.1.
type SignatureFlags uint32
// SignatureFlag values as defined in [PROTOCOL.agent] section 5.3.
const (
SignatureFlagReserved SignatureFlags = 1 << iota
SignatureFlagRsaSha256
SignatureFlagRsaSha512
)
// Agent represents the capabilities of an ssh-agent.
type Agent interface {
// List returns the identities known to the agent.
List() ([]*Key, error)
// Sign has the agent sign the data using a protocol 2 key as defined
// in [PROTOCOL.agent] section 2.6.2.
Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error)
// Add adds a private key to the agent.
Add(key AddedKey) error
// Remove removes all identities with the given public key.
Remove(key ssh.PublicKey) error
// RemoveAll removes all identities.
RemoveAll() error
// Lock locks the agent. Sign and Remove will fail, and List will empty an empty list.
Lock(passphrase []byte) error
// Unlock undoes the effect of Lock
Unlock(passphrase []byte) error
// Signers returns signers for all the known keys.
Signers() ([]ssh.Signer, error)
}
type ExtendedAgent interface {
Agent
// SignWithFlags signs like Sign, but allows for additional flags to be sent/received
SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureFlags) (*ssh.Signature, error)
// Extension processes a custom extension request. Standard-compliant agents are not
// required to support any extensions, but this method allows agents to implement
// vendor-specific methods or add experimental features. See [PROTOCOL.agent] section 4.7.
// If agent extensions are unsupported entirely this method MUST return an
// ErrExtensionUnsupported error. Similarly, if just the specific extensionType in
// the request is unsupported by the agent then ErrExtensionUnsupported MUST be
// returned.
//
// In the case of success, since [PROTOCOL.agent] section 4.7 specifies that the contents
// of the response are unspecified (including the type of the message), the complete
// response will be returned as a []byte slice, including the "type" byte of the message.
Extension(extensionType string, contents []byte) ([]byte, error)
}
// ConstraintExtension describes an optional constraint defined by users.
type ConstraintExtension struct {
// ExtensionName consist of a UTF-8 string suffixed by the
// implementation domain following the naming scheme defined
// in Section 4.2 of RFC 4251, e.g. "foo@example.com".
ExtensionName string
// ExtensionDetails contains the actual content of the extended
// constraint.
ExtensionDetails []byte
}
// AddedKey describes an SSH key to be added to an Agent.
type AddedKey struct {
// PrivateKey must be a *rsa.PrivateKey, *dsa.PrivateKey,
// ed25519.PrivateKey or *ecdsa.PrivateKey, which will be inserted into the
// agent.
PrivateKey interface{}
// Certificate, if not nil, is communicated to the agent and will be
// stored with the key.
Certificate *ssh.Certificate
// Comment is an optional, free-form string.
Comment string
// LifetimeSecs, if not zero, is the number of seconds that the
// agent will store the key for.
LifetimeSecs uint32
// ConfirmBeforeUse, if true, requests that the agent confirm with the
// user before each use of this key.
ConfirmBeforeUse bool
// ConstraintExtensions are the experimental or private-use constraints
// defined by users.
ConstraintExtensions []ConstraintExtension
}
// See [PROTOCOL.agent], section 3.
const (
agentRequestV1Identities = 1
agentRemoveAllV1Identities = 9
// 3.2 Requests from client to agent for protocol 2 key operations
agentAddIdentity = 17
agentRemoveIdentity = 18
agentRemoveAllIdentities = 19
agentAddIDConstrained = 25
// 3.3 Key-type independent requests from client to agent
agentAddSmartcardKey = 20
agentRemoveSmartcardKey = 21
agentLock = 22
agentUnlock = 23
agentAddSmartcardKeyConstrained = 26
// 3.7 Key constraint identifiers
agentConstrainLifetime = 1
agentConstrainConfirm = 2
// Constraint extension identifier up to version 2 of the protocol. A
// backward incompatible change will be required if we want to add support
// for SSH_AGENT_CONSTRAIN_MAXSIGN which uses the same ID.
agentConstrainExtensionV00 = 3
// Constraint extension identifier in version 3 and later of the protocol.
agentConstrainExtension = 255
)
// maxAgentResponseBytes is the maximum agent reply size that is accepted. This
// is a sanity check, not a limit in the spec.
const maxAgentResponseBytes = 16 << 20
// Agent messages:
// These structures mirror the wire format of the corresponding ssh agent
// messages found in [PROTOCOL.agent].
// 3.4 Generic replies from agent to client
const agentFailure = 5
type failureAgentMsg struct{}
const agentSuccess = 6
type successAgentMsg struct{}
// See [PROTOCOL.agent], section 2.5.2.
const agentRequestIdentities = 11
type requestIdentitiesAgentMsg struct{}
// See [PROTOCOL.agent], section 2.5.2.
const agentIdentitiesAnswer = 12
type identitiesAnswerAgentMsg struct {
NumKeys uint32 `sshtype:"12"`
Keys []byte `ssh:"rest"`
}
// See [PROTOCOL.agent], section 2.6.2.
const agentSignRequest = 13
type signRequestAgentMsg struct {
KeyBlob []byte `sshtype:"13"`
Data []byte
Flags uint32
}
// See [PROTOCOL.agent], section 2.6.2.
// 3.6 Replies from agent to client for protocol 2 key operations
const agentSignResponse = 14
type signResponseAgentMsg struct {
SigBlob []byte `sshtype:"14"`
}
type publicKey struct {
Format string
Rest []byte `ssh:"rest"`
}
// 3.7 Key constraint identifiers
type constrainLifetimeAgentMsg struct {
LifetimeSecs uint32 `sshtype:"1"`
}
type constrainExtensionAgentMsg struct {
ExtensionName string `sshtype:"255|3"`
ExtensionDetails []byte
// Rest is a field used for parsing, not part of message
Rest []byte `ssh:"rest"`
}
// See [PROTOCOL.agent], section 4.7
const agentExtension = 27
const agentExtensionFailure = 28
// ErrExtensionUnsupported indicates that an extension defined in
// [PROTOCOL.agent] section 4.7 is unsupported by the agent. Specifically this
// error indicates that the agent returned a standard SSH_AGENT_FAILURE message
// as the result of a SSH_AGENTC_EXTENSION request. Note that the protocol
// specification (and therefore this error) does not distinguish between a
// specific extension being unsupported and extensions being unsupported entirely.
var ErrExtensionUnsupported = errors.New("agent: extension unsupported")
type extensionAgentMsg struct {
ExtensionType string `sshtype:"27"`
// NOTE: this matches OpenSSH's PROTOCOL.agent, not the IETF draft [PROTOCOL.agent],
// so that it matches what OpenSSH actually implements in the wild.
Contents []byte `ssh:"rest"`
}
// Key represents a protocol 2 public key as defined in
// [PROTOCOL.agent], section 2.5.2.
type Key struct {
Format string
Blob []byte
Comment string
}
func clientErr(err error) error {
return fmt.Errorf("agent: client error: %v", err)
}
// String returns the storage form of an agent key with the format, base64
// encoded serialized key, and the comment if it is not empty.
func (k *Key) String() string {
s := string(k.Format) + " " + base64.StdEncoding.EncodeToString(k.Blob)
if k.Comment != "" {
s += " " + k.Comment
}
return s
}
// Type returns the public key type.
func (k *Key) Type() string {
return k.Format
}
// Marshal returns key blob to satisfy the ssh.PublicKey interface.
func (k *Key) Marshal() []byte {
return k.Blob
}
// Verify satisfies the ssh.PublicKey interface.
func (k *Key) Verify(data []byte, sig *ssh.Signature) error {
pubKey, err := ssh.ParsePublicKey(k.Blob)
if err != nil {
return fmt.Errorf("agent: bad public key: %v", err)
}
return pubKey.Verify(data, sig)
}
type wireKey struct {
Format string
Rest []byte `ssh:"rest"`
}
func parseKey(in []byte) (out *Key, rest []byte, err error) {
var record struct {
Blob []byte
Comment string
Rest []byte `ssh:"rest"`
}
if err := ssh.Unmarshal(in, &record); err != nil {
return nil, nil, err
}
var wk wireKey
if err := ssh.Unmarshal(record.Blob, &wk); err != nil {
return nil, nil, err
}
return &Key{
Format: wk.Format,
Blob: record.Blob,
Comment: record.Comment,
}, record.Rest, nil
}
// client is a client for an ssh-agent process.
type client struct {
// conn is typically a *net.UnixConn
conn io.ReadWriter
// mu is used to prevent concurrent access to the agent
mu sync.Mutex
}
// NewClient returns an Agent that talks to an ssh-agent process over
// the given connection.
func NewClient(rw io.ReadWriter) ExtendedAgent {
return &client{conn: rw}
}
// call sends an RPC to the agent. On success, the reply is
// unmarshaled into reply and replyType is set to the first byte of
// the reply, which contains the type of the message.
func (c *client) call(req []byte) (reply interface{}, err error) {
buf, err := c.callRaw(req)
if err != nil {
return nil, err
}
reply, err = unmarshal(buf)
if err != nil {
return nil, clientErr(err)
}
return reply, nil
}
// callRaw sends an RPC to the agent. On success, the raw
// bytes of the response are returned; no unmarshalling is
// performed on the response.
func (c *client) callRaw(req []byte) (reply []byte, err error) {
c.mu.Lock()
defer c.mu.Unlock()
msg := make([]byte, 4+len(req))
binary.BigEndian.PutUint32(msg, uint32(len(req)))
copy(msg[4:], req)
if _, err = c.conn.Write(msg); err != nil {
return nil, clientErr(err)
}
var respSizeBuf [4]byte
if _, err = io.ReadFull(c.conn, respSizeBuf[:]); err != nil {
return nil, clientErr(err)
}
respSize := binary.BigEndian.Uint32(respSizeBuf[:])
if respSize > maxAgentResponseBytes {
return nil, clientErr(errors.New("response too large"))
}
buf := make([]byte, respSize)
if _, err = io.ReadFull(c.conn, buf); err != nil {
return nil, clientErr(err)
}
return buf, nil
}
func (c *client) simpleCall(req []byte) error {
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
func (c *client) RemoveAll() error {
return c.simpleCall([]byte{agentRemoveAllIdentities})
}
func (c *client) Remove(key ssh.PublicKey) error {
req := ssh.Marshal(&agentRemoveIdentityMsg{
KeyBlob: key.Marshal(),
})
return c.simpleCall(req)
}
func (c *client) Lock(passphrase []byte) error {
req := ssh.Marshal(&agentLockMsg{
Passphrase: passphrase,
})
return c.simpleCall(req)
}
func (c *client) Unlock(passphrase []byte) error {
req := ssh.Marshal(&agentUnlockMsg{
Passphrase: passphrase,
})
return c.simpleCall(req)
}
// List returns the identities known to the agent.
func (c *client) List() ([]*Key, error) {
// see [PROTOCOL.agent] section 2.5.2.
req := []byte{agentRequestIdentities}
msg, err := c.call(req)
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *identitiesAnswerAgentMsg:
if msg.NumKeys > maxAgentResponseBytes/8 {
return nil, errors.New("agent: too many keys in agent reply")
}
keys := make([]*Key, msg.NumKeys)
data := msg.Keys
for i := uint32(0); i < msg.NumKeys; i++ {
var key *Key
var err error
if key, data, err = parseKey(data); err != nil {
return nil, err
}
keys[i] = key
}
return keys, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to list keys")
}
panic("unreachable")
}
// Sign has the agent sign the data using a protocol 2 key as defined
// in [PROTOCOL.agent] section 2.6.2.
func (c *client) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
return c.SignWithFlags(key, data, 0)
}
func (c *client) SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureFlags) (*ssh.Signature, error) {
req := ssh.Marshal(signRequestAgentMsg{
KeyBlob: key.Marshal(),
Data: data,
Flags: uint32(flags),
})
msg, err := c.call(req)
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *signResponseAgentMsg:
var sig ssh.Signature
if err := ssh.Unmarshal(msg.SigBlob, &sig); err != nil {
return nil, err
}
return &sig, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to sign challenge")
}
panic("unreachable")
}
// unmarshal parses an agent message in packet, returning the parsed
// form and the message type of packet.
func unmarshal(packet []byte) (interface{}, error) {
if len(packet) < 1 {
return nil, errors.New("agent: empty packet")
}
var msg interface{}
switch packet[0] {
case agentFailure:
return new(failureAgentMsg), nil
case agentSuccess:
return new(successAgentMsg), nil
case agentIdentitiesAnswer:
msg = new(identitiesAnswerAgentMsg)
case agentSignResponse:
msg = new(signResponseAgentMsg)
case agentV1IdentitiesAnswer:
msg = new(agentV1IdentityMsg)
default:
return nil, fmt.Errorf("agent: unknown type tag %d", packet[0])
}
if err := ssh.Unmarshal(packet, msg); err != nil {
return nil, err
}
return msg, nil
}
type rsaKeyMsg struct {
Type string `sshtype:"17|25"`
N *big.Int
E *big.Int
D *big.Int
Iqmp *big.Int // IQMP = Inverse Q Mod P
P *big.Int
Q *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type dsaKeyMsg struct {
Type string `sshtype:"17|25"`
P *big.Int
Q *big.Int
G *big.Int
Y *big.Int
X *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ecdsaKeyMsg struct {
Type string `sshtype:"17|25"`
Curve string
KeyBytes []byte
D *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ed25519KeyMsg struct {
Type string `sshtype:"17|25"`
Pub []byte
Priv []byte
Comments string
Constraints []byte `ssh:"rest"`
}
// Insert adds a private key to the agent.
func (c *client) insertKey(s interface{}, comment string, constraints []byte) error {
var req []byte
switch k := s.(type) {
case *rsa.PrivateKey:
if len(k.Primes) != 2 {
return fmt.Errorf("agent: unsupported RSA key with %d primes", len(k.Primes))
}
k.Precompute()
req = ssh.Marshal(rsaKeyMsg{
Type: ssh.KeyAlgoRSA,
N: k.N,
E: big.NewInt(int64(k.E)),
D: k.D,
Iqmp: k.Precomputed.Qinv,
P: k.Primes[0],
Q: k.Primes[1],
Comments: comment,
Constraints: constraints,
})
case *dsa.PrivateKey:
req = ssh.Marshal(dsaKeyMsg{
Type: ssh.KeyAlgoDSA,
P: k.P,
Q: k.Q,
G: k.G,
Y: k.Y,
X: k.X,
Comments: comment,
Constraints: constraints,
})
case *ecdsa.PrivateKey:
nistID := fmt.Sprintf("nistp%d", k.Params().BitSize)
req = ssh.Marshal(ecdsaKeyMsg{
Type: "ecdsa-sha2-" + nistID,
Curve: nistID,
KeyBytes: elliptic.Marshal(k.Curve, k.X, k.Y),
D: k.D,
Comments: comment,
Constraints: constraints,
})
case ed25519.PrivateKey:
req = ssh.Marshal(ed25519KeyMsg{
Type: ssh.KeyAlgoED25519,
Pub: []byte(k)[32:],
Priv: []byte(k),
Comments: comment,
Constraints: constraints,
})
// This function originally supported only *ed25519.PrivateKey, however the
// general idiom is to pass ed25519.PrivateKey by value, not by pointer.
// We still support the pointer variant for backwards compatibility.
case *ed25519.PrivateKey:
req = ssh.Marshal(ed25519KeyMsg{
Type: ssh.KeyAlgoED25519,
Pub: []byte(*k)[32:],
Priv: []byte(*k),
Comments: comment,
Constraints: constraints,
})
default:
return fmt.Errorf("agent: unsupported key type %T", s)
}
// if constraints are present then the message type needs to be changed.
if len(constraints) != 0 {
req[0] = agentAddIDConstrained
}
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
type rsaCertMsg struct {
Type string `sshtype:"17|25"`
CertBytes []byte
D *big.Int
Iqmp *big.Int // IQMP = Inverse Q Mod P
P *big.Int
Q *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type dsaCertMsg struct {
Type string `sshtype:"17|25"`
CertBytes []byte
X *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ecdsaCertMsg struct {
Type string `sshtype:"17|25"`
CertBytes []byte
D *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ed25519CertMsg struct {
Type string `sshtype:"17|25"`
CertBytes []byte
Pub []byte
Priv []byte
Comments string
Constraints []byte `ssh:"rest"`
}
// Add adds a private key to the agent. If a certificate is given,
// that certificate is added instead as public key.
func (c *client) Add(key AddedKey) error {
var constraints []byte
if secs := key.LifetimeSecs; secs != 0 {
constraints = append(constraints, ssh.Marshal(constrainLifetimeAgentMsg{secs})...)
}
if key.ConfirmBeforeUse {
constraints = append(constraints, agentConstrainConfirm)
}
cert := key.Certificate
if cert == nil {
return c.insertKey(key.PrivateKey, key.Comment, constraints)
}
return c.insertCert(key.PrivateKey, cert, key.Comment, constraints)
}
func (c *client) insertCert(s interface{}, cert *ssh.Certificate, comment string, constraints []byte) error {
var req []byte
switch k := s.(type) {
case *rsa.PrivateKey:
if len(k.Primes) != 2 {
return fmt.Errorf("agent: unsupported RSA key with %d primes", len(k.Primes))
}
k.Precompute()
req = ssh.Marshal(rsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
D: k.D,
Iqmp: k.Precomputed.Qinv,
P: k.Primes[0],
Q: k.Primes[1],
Comments: comment,
Constraints: constraints,
})
case *dsa.PrivateKey:
req = ssh.Marshal(dsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
X: k.X,
Comments: comment,
Constraints: constraints,
})
case *ecdsa.PrivateKey:
req = ssh.Marshal(ecdsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
D: k.D,
Comments: comment,
Constraints: constraints,
})
case ed25519.PrivateKey:
req = ssh.Marshal(ed25519CertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
Pub: []byte(k)[32:],
Priv: []byte(k),
Comments: comment,
Constraints: constraints,
})
// This function originally supported only *ed25519.PrivateKey, however the
// general idiom is to pass ed25519.PrivateKey by value, not by pointer.
// We still support the pointer variant for backwards compatibility.
case *ed25519.PrivateKey:
req = ssh.Marshal(ed25519CertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
Pub: []byte(*k)[32:],
Priv: []byte(*k),
Comments: comment,
Constraints: constraints,
})
default:
return fmt.Errorf("agent: unsupported key type %T", s)
}
// if constraints are present then the message type needs to be changed.
if len(constraints) != 0 {
req[0] = agentAddIDConstrained
}
signer, err := ssh.NewSignerFromKey(s)
if err != nil {
return err
}
if !bytes.Equal(cert.Key.Marshal(), signer.PublicKey().Marshal()) {
return errors.New("agent: signer and cert have different public key")
}
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
// Signers provides a callback for client authentication.
func (c *client) Signers() ([]ssh.Signer, error) {
keys, err := c.List()
if err != nil {
return nil, err
}
var result []ssh.Signer
for _, k := range keys {
result = append(result, &agentKeyringSigner{c, k})
}
return result, nil
}
type agentKeyringSigner struct {
agent *client
pub ssh.PublicKey
}
func (s *agentKeyringSigner) PublicKey() ssh.PublicKey {
return s.pub
}
func (s *agentKeyringSigner) Sign(rand io.Reader, data []byte) (*ssh.Signature, error) {
// The agent has its own entropy source, so the rand argument is ignored.
return s.agent.Sign(s.pub, data)
}
func (s *agentKeyringSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*ssh.Signature, error) {
if algorithm == "" || algorithm == underlyingAlgo(s.pub.Type()) {
return s.Sign(rand, data)
}
var flags SignatureFlags
switch algorithm {
case ssh.KeyAlgoRSASHA256:
flags = SignatureFlagRsaSha256
case ssh.KeyAlgoRSASHA512:
flags = SignatureFlagRsaSha512
default:
return nil, fmt.Errorf("agent: unsupported algorithm %q", algorithm)
}
return s.agent.SignWithFlags(s.pub, data, flags)
}
var _ ssh.AlgorithmSigner = &agentKeyringSigner{}
// certKeyAlgoNames is a mapping from known certificate algorithm names to the
// corresponding public key signature algorithm.
//
// This map must be kept in sync with the one in certs.go.
var certKeyAlgoNames = map[string]string{
ssh.CertAlgoRSAv01: ssh.KeyAlgoRSA,
ssh.CertAlgoRSASHA256v01: ssh.KeyAlgoRSASHA256,
ssh.CertAlgoRSASHA512v01: ssh.KeyAlgoRSASHA512,
ssh.CertAlgoDSAv01: ssh.KeyAlgoDSA,
ssh.CertAlgoECDSA256v01: ssh.KeyAlgoECDSA256,
ssh.CertAlgoECDSA384v01: ssh.KeyAlgoECDSA384,
ssh.CertAlgoECDSA521v01: ssh.KeyAlgoECDSA521,
ssh.CertAlgoSKECDSA256v01: ssh.KeyAlgoSKECDSA256,
ssh.CertAlgoED25519v01: ssh.KeyAlgoED25519,
ssh.CertAlgoSKED25519v01: ssh.KeyAlgoSKED25519,
}
// underlyingAlgo returns the signature algorithm associated with algo (which is
// an advertised or negotiated public key or host key algorithm). These are
// usually the same, except for certificate algorithms.
func underlyingAlgo(algo string) string {
if a, ok := certKeyAlgoNames[algo]; ok {
return a
}
return algo
}
// Calls an extension method. It is up to the agent implementation as to whether or not
// any particular extension is supported and may always return an error. Because the
// type of the response is up to the implementation, this returns the bytes of the
// response and does not attempt any type of unmarshalling.
func (c *client) Extension(extensionType string, contents []byte) ([]byte, error) {
req := ssh.Marshal(extensionAgentMsg{
ExtensionType: extensionType,
Contents: contents,
})
buf, err := c.callRaw(req)
if err != nil {
return nil, err
}
if len(buf) == 0 {
return nil, errors.New("agent: failure; empty response")
}
// [PROTOCOL.agent] section 4.7 indicates that an SSH_AGENT_FAILURE message
// represents an agent that does not support the extension
if buf[0] == agentFailure {
return nil, ErrExtensionUnsupported
}
if buf[0] == agentExtensionFailure {
return nil, errors.New("agent: generic extension failure")
}
return buf, nil
}

103
pkg/proto/ssh/agent/forward.go
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@ -1,103 +0,0 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"errors"
"io"
"net"
"sync"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
// RequestAgentForwarding sets up agent forwarding for the session.
// ForwardToAgent or ForwardToRemote should be called to route
// the authentication requests.
func RequestAgentForwarding(session *ssh.Session) error {
ok, err := session.SendRequest("auth-agent-req@openssh.com", true, nil)
if err != nil {
return err
}
if !ok {
return errors.New("forwarding request denied")
}
return nil
}
// ForwardToAgent routes authentication requests to the given keyring.
func ForwardToAgent(client *ssh.Client, keyring Agent) error {
channels := client.HandleChannelOpen(channelType)
if channels == nil {
return errors.New("agent: already have handler for " + channelType)
}
go func() {
for ch := range channels {
channel, reqs, err := ch.Accept()
if err != nil {
continue
}
go ssh.DiscardRequests(reqs)
go func() {
ServeAgent(keyring, channel)
channel.Close()
}()
}
}()
return nil
}
const channelType = "auth-agent@openssh.com"
// ForwardToRemote routes authentication requests to the ssh-agent
// process serving on the given unix socket.
func ForwardToRemote(client *ssh.Client, addr string) error {
channels := client.HandleChannelOpen(channelType)
if channels == nil {
return errors.New("agent: already have handler for " + channelType)
}
conn, err := net.Dial("unix", addr)
if err != nil {
return err
}
conn.Close()
go func() {
for ch := range channels {
channel, reqs, err := ch.Accept()
if err != nil {
continue
}
go ssh.DiscardRequests(reqs)
go forwardUnixSocket(channel, addr)
}
}()
return nil
}
func forwardUnixSocket(channel ssh.Channel, addr string) {
conn, err := net.Dial("unix", addr)
if err != nil {
return
}
var wg sync.WaitGroup
wg.Add(2)
go func() {
io.Copy(conn, channel)
conn.(*net.UnixConn).CloseWrite()
wg.Done()
}()
go func() {
io.Copy(channel, conn)
channel.CloseWrite()
wg.Done()
}()
wg.Wait()
conn.Close()
channel.Close()
}

241
pkg/proto/ssh/agent/keyring.go
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@ -1,241 +0,0 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"bytes"
"crypto/rand"
"crypto/subtle"
"errors"
"fmt"
"sync"
"time"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
type privKey struct {
signer ssh.Signer
comment string
expire *time.Time
}
type keyring struct {
mu sync.Mutex
keys []privKey
locked bool
passphrase []byte
}
var errLocked = errors.New("agent: locked")
// NewKeyring returns an Agent that holds keys in memory. It is safe
// for concurrent use by multiple goroutines.
func NewKeyring() Agent {
return &keyring{}
}
// RemoveAll removes all identities.
func (r *keyring) RemoveAll() error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
r.keys = nil
return nil
}
// removeLocked does the actual key removal. The caller must already be holding the
// keyring mutex.
func (r *keyring) removeLocked(want []byte) error {
found := false
for i := 0; i < len(r.keys); {
if bytes.Equal(r.keys[i].signer.PublicKey().Marshal(), want) {
found = true
r.keys[i] = r.keys[len(r.keys)-1]
r.keys = r.keys[:len(r.keys)-1]
continue
} else {
i++
}
}
if !found {
return errors.New("agent: key not found")
}
return nil
}
// Remove removes all identities with the given public key.
func (r *keyring) Remove(key ssh.PublicKey) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
return r.removeLocked(key.Marshal())
}
// Lock locks the agent. Sign and Remove will fail, and List will return an empty list.
func (r *keyring) Lock(passphrase []byte) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
r.locked = true
r.passphrase = passphrase
return nil
}
// Unlock undoes the effect of Lock
func (r *keyring) Unlock(passphrase []byte) error {
r.mu.Lock()
defer r.mu.Unlock()
if !r.locked {
return errors.New("agent: not locked")
}
if 1 != subtle.ConstantTimeCompare(passphrase, r.passphrase) {
return fmt.Errorf("agent: incorrect passphrase")
}
r.locked = false
r.passphrase = nil
return nil
}
// expireKeysLocked removes expired keys from the keyring. If a key was added
// with a lifetimesecs contraint and seconds >= lifetimesecs seconds have
// elapsed, it is removed. The caller *must* be holding the keyring mutex.
func (r *keyring) expireKeysLocked() {
for _, k := range r.keys {
if k.expire != nil && time.Now().After(*k.expire) {
r.removeLocked(k.signer.PublicKey().Marshal())
}
}
}
// List returns the identities known to the agent.
func (r *keyring) List() ([]*Key, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
// section 2.7: locked agents return empty.
return nil, nil
}
r.expireKeysLocked()
var ids []*Key
for _, k := range r.keys {
pub := k.signer.PublicKey()
ids = append(ids, &Key{
Format: pub.Type(),
Blob: pub.Marshal(),
Comment: k.comment})
}
return ids, nil
}
// Insert adds a private key to the keyring. If a certificate
// is given, that certificate is added as public key. Note that
// any constraints given are ignored.
func (r *keyring) Add(key AddedKey) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
signer, err := ssh.NewSignerFromKey(key.PrivateKey)
if err != nil {
return err
}
if cert := key.Certificate; cert != nil {
signer, err = ssh.NewCertSigner(cert, signer)
if err != nil {
return err
}
}
p := privKey{
signer: signer,
comment: key.Comment,
}
if key.LifetimeSecs > 0 {
t := time.Now().Add(time.Duration(key.LifetimeSecs) * time.Second)
p.expire = &t
}
r.keys = append(r.keys, p)
return nil
}
// Sign returns a signature for the data.
func (r *keyring) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
return r.SignWithFlags(key, data, 0)
}
func (r *keyring) SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureFlags) (*ssh.Signature, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return nil, errLocked
}
r.expireKeysLocked()
wanted := key.Marshal()
for _, k := range r.keys {
if bytes.Equal(k.signer.PublicKey().Marshal(), wanted) {
if flags == 0 {
return k.signer.Sign(rand.Reader, data)
} else {
if algorithmSigner, ok := k.signer.(ssh.AlgorithmSigner); !ok {
return nil, fmt.Errorf("agent: signature does not support non-default signature algorithm: %T", k.signer)
} else {
var algorithm string
switch flags {
case SignatureFlagRsaSha256:
algorithm = ssh.KeyAlgoRSASHA256
case SignatureFlagRsaSha512:
algorithm = ssh.KeyAlgoRSASHA512
default:
return nil, fmt.Errorf("agent: unsupported signature flags: %d", flags)
}
return algorithmSigner.SignWithAlgorithm(rand.Reader, data, algorithm)
}
}
}
}
return nil, errors.New("not found")
}
// Signers returns signers for all the known keys.
func (r *keyring) Signers() ([]ssh.Signer, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return nil, errLocked
}
r.expireKeysLocked()
s := make([]ssh.Signer, 0, len(r.keys))
for _, k := range r.keys {
s = append(s, k.signer)
}
return s, nil
}
// The keyring does not support any extensions
func (r *keyring) Extension(extensionType string, contents []byte) ([]byte, error) {
return nil, ErrExtensionUnsupported
}

570
pkg/proto/ssh/agent/server.go
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@ -1,570 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"crypto/dsa"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rsa"
"encoding/binary"
"errors"
"fmt"
"io"
"log"
"math/big"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
// server wraps an Agent and uses it to implement the agent side of
// the SSH-agent, wire protocol.
type server struct {
agent Agent
}
func (s *server) processRequestBytes(reqData []byte) []byte {
rep, err := s.processRequest(reqData)
if err != nil {
if err != errLocked {
// TODO(hanwen): provide better logging interface?
log.Printf("agent %d: %v", reqData[0], err)
}
return []byte{agentFailure}
}
if err == nil && rep == nil {
return []byte{agentSuccess}
}
return ssh.Marshal(rep)
}
func marshalKey(k *Key) []byte {
var record struct {
Blob []byte
Comment string
}
record.Blob = k.Marshal()
record.Comment = k.Comment
return ssh.Marshal(&record)
}
// See [PROTOCOL.agent], section 2.5.1.
const agentV1IdentitiesAnswer = 2
type agentV1IdentityMsg struct {
Numkeys uint32 `sshtype:"2"`
}
type agentRemoveIdentityMsg struct {
KeyBlob []byte `sshtype:"18"`
}
type agentLockMsg struct {
Passphrase []byte `sshtype:"22"`
}
type agentUnlockMsg struct {
Passphrase []byte `sshtype:"23"`
}
func (s *server) processRequest(data []byte) (interface{}, error) {
switch data[0] {
case agentRequestV1Identities:
return &agentV1IdentityMsg{0}, nil
case agentRemoveAllV1Identities:
return nil, nil
case agentRemoveIdentity:
var req agentRemoveIdentityMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
var wk wireKey
if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
return nil, err
}
return nil, s.agent.Remove(&Key{Format: wk.Format, Blob: req.KeyBlob})
case agentRemoveAllIdentities:
return nil, s.agent.RemoveAll()
case agentLock:
var req agentLockMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
return nil, s.agent.Lock(req.Passphrase)
case agentUnlock:
var req agentUnlockMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
return nil, s.agent.Unlock(req.Passphrase)
case agentSignRequest:
var req signRequestAgentMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
var wk wireKey
if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
return nil, err
}
k := &Key{
Format: wk.Format,
Blob: req.KeyBlob,
}
var sig *ssh.Signature
var err error
if extendedAgent, ok := s.agent.(ExtendedAgent); ok {
sig, err = extendedAgent.SignWithFlags(k, req.Data, SignatureFlags(req.Flags))
} else {
sig, err = s.agent.Sign(k, req.Data)
}
if err != nil {
return nil, err
}
return &signResponseAgentMsg{SigBlob: ssh.Marshal(sig)}, nil
case agentRequestIdentities:
keys, err := s.agent.List()
if err != nil {
return nil, err
}
rep := identitiesAnswerAgentMsg{
NumKeys: uint32(len(keys)),
}
for _, k := range keys {
rep.Keys = append(rep.Keys, marshalKey(k)...)
}
return rep, nil
case agentAddIDConstrained, agentAddIdentity:
return nil, s.insertIdentity(data)
case agentExtension:
// Return a stub object where the whole contents of the response gets marshaled.
var responseStub struct {
Rest []byte `ssh:"rest"`
}
if extendedAgent, ok := s.agent.(ExtendedAgent); !ok {
// If this agent doesn't implement extensions, [PROTOCOL.agent] section 4.7
// requires that we return a standard SSH_AGENT_FAILURE message.
responseStub.Rest = []byte{agentFailure}
} else {
var req extensionAgentMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
res, err := extendedAgent.Extension(req.ExtensionType, req.Contents)
if err != nil {
// If agent extensions are unsupported, return a standard SSH_AGENT_FAILURE
// message as required by [PROTOCOL.agent] section 4.7.
if err == ErrExtensionUnsupported {
responseStub.Rest = []byte{agentFailure}
} else {
// As the result of any other error processing an extension request,
// [PROTOCOL.agent] section 4.7 requires that we return a
// SSH_AGENT_EXTENSION_FAILURE code.
responseStub.Rest = []byte{agentExtensionFailure}
}
} else {
if len(res) == 0 {
return nil, nil
}
responseStub.Rest = res
}
}
return responseStub, nil
}
return nil, fmt.Errorf("unknown opcode %d", data[0])
}
func parseConstraints(constraints []byte) (lifetimeSecs uint32, confirmBeforeUse bool, extensions []ConstraintExtension, err error) {
for len(constraints) != 0 {
switch constraints[0] {
case agentConstrainLifetime:
lifetimeSecs = binary.BigEndian.Uint32(constraints[1:5])
constraints = constraints[5:]
case agentConstrainConfirm:
confirmBeforeUse = true
constraints = constraints[1:]
case agentConstrainExtension, agentConstrainExtensionV00:
var msg constrainExtensionAgentMsg
if err = ssh.Unmarshal(constraints, &msg); err != nil {
return 0, false, nil, err
}
extensions = append(extensions, ConstraintExtension{
ExtensionName: msg.ExtensionName,
ExtensionDetails: msg.ExtensionDetails,
})
constraints = msg.Rest
default:
return 0, false, nil, fmt.Errorf("unknown constraint type: %d", constraints[0])
}
}
return
}
func setConstraints(key *AddedKey, constraintBytes []byte) error {
lifetimeSecs, confirmBeforeUse, constraintExtensions, err := parseConstraints(constraintBytes)
if err != nil {
return err
}
key.LifetimeSecs = lifetimeSecs
key.ConfirmBeforeUse = confirmBeforeUse
key.ConstraintExtensions = constraintExtensions
return nil
}
func parseRSAKey(req []byte) (*AddedKey, error) {
var k rsaKeyMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
if k.E.BitLen() > 30 {
return nil, errors.New("agent: RSA public exponent too large")
}
priv := &rsa.PrivateKey{
PublicKey: rsa.PublicKey{
E: int(k.E.Int64()),
N: k.N,
},
D: k.D,
Primes: []*big.Int{k.P, k.Q},
}
priv.Precompute()
addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseEd25519Key(req []byte) (*AddedKey, error) {
var k ed25519KeyMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
priv := ed25519.PrivateKey(k.Priv)
addedKey := &AddedKey{PrivateKey: &priv, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseDSAKey(req []byte) (*AddedKey, error) {
var k dsaKeyMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
priv := &dsa.PrivateKey{
PublicKey: dsa.PublicKey{
Parameters: dsa.Parameters{
P: k.P,
Q: k.Q,
G: k.G,
},
Y: k.Y,
},
X: k.X,
}
addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func unmarshalECDSA(curveName string, keyBytes []byte, privScalar *big.Int) (priv *ecdsa.PrivateKey, err error) {
priv = &ecdsa.PrivateKey{
D: privScalar,
}
switch curveName {
case "nistp256":
priv.Curve = elliptic.P256()
case "nistp384":
priv.Curve = elliptic.P384()
case "nistp521":
priv.Curve = elliptic.P521()
default:
return nil, fmt.Errorf("agent: unknown curve %q", curveName)
}
priv.X, priv.Y = elliptic.Unmarshal(priv.Curve, keyBytes)
if priv.X == nil || priv.Y == nil {
return nil, errors.New("agent: point not on curve")
}
return priv, nil
}
func parseEd25519Cert(req []byte) (*AddedKey, error) {
var k ed25519CertMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
pubKey, err := ssh.ParsePublicKey(k.CertBytes)
if err != nil {
return nil, err
}
priv := ed25519.PrivateKey(k.Priv)
cert, ok := pubKey.(*ssh.Certificate)
if !ok {
return nil, errors.New("agent: bad ED25519 certificate")
}
addedKey := &AddedKey{PrivateKey: &priv, Certificate: cert, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseECDSAKey(req []byte) (*AddedKey, error) {
var k ecdsaKeyMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
priv, err := unmarshalECDSA(k.Curve, k.KeyBytes, k.D)
if err != nil {
return nil, err
}
addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseRSACert(req []byte) (*AddedKey, error) {
var k rsaCertMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
pubKey, err := ssh.ParsePublicKey(k.CertBytes)
if err != nil {
return nil, err
}
cert, ok := pubKey.(*ssh.Certificate)
if !ok {
return nil, errors.New("agent: bad RSA certificate")
}
// An RSA publickey as marshaled by rsaPublicKey.Marshal() in keys.go
var rsaPub struct {
Name string
E *big.Int
N *big.Int
}
if err := ssh.Unmarshal(cert.Key.Marshal(), &rsaPub); err != nil {
return nil, fmt.Errorf("agent: Unmarshal failed to parse public key: %v", err)
}
if rsaPub.E.BitLen() > 30 {
return nil, errors.New("agent: RSA public exponent too large")
}
priv := rsa.PrivateKey{
PublicKey: rsa.PublicKey{
E: int(rsaPub.E.Int64()),
N: rsaPub.N,
},
D: k.D,
Primes: []*big.Int{k.Q, k.P},
}
priv.Precompute()
addedKey := &AddedKey{PrivateKey: &priv, Certificate: cert, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseDSACert(req []byte) (*AddedKey, error) {
var k dsaCertMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
pubKey, err := ssh.ParsePublicKey(k.CertBytes)
if err != nil {
return nil, err
}
cert, ok := pubKey.(*ssh.Certificate)
if !ok {
return nil, errors.New("agent: bad DSA certificate")
}
// A DSA publickey as marshaled by dsaPublicKey.Marshal() in keys.go
var w struct {
Name string
P, Q, G, Y *big.Int
}
if err := ssh.Unmarshal(cert.Key.Marshal(), &w); err != nil {
return nil, fmt.Errorf("agent: Unmarshal failed to parse public key: %v", err)
}
priv := &dsa.PrivateKey{
PublicKey: dsa.PublicKey{
Parameters: dsa.Parameters{
P: w.P,
Q: w.Q,
G: w.G,
},
Y: w.Y,
},
X: k.X,
}
addedKey := &AddedKey{PrivateKey: priv, Certificate: cert, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func parseECDSACert(req []byte) (*AddedKey, error) {
var k ecdsaCertMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return nil, err
}
pubKey, err := ssh.ParsePublicKey(k.CertBytes)
if err != nil {
return nil, err
}
cert, ok := pubKey.(*ssh.Certificate)
if !ok {
return nil, errors.New("agent: bad ECDSA certificate")
}
// An ECDSA publickey as marshaled by ecdsaPublicKey.Marshal() in keys.go
var ecdsaPub struct {
Name string
ID string
Key []byte
}
if err := ssh.Unmarshal(cert.Key.Marshal(), &ecdsaPub); err != nil {
return nil, err
}
priv, err := unmarshalECDSA(ecdsaPub.ID, ecdsaPub.Key, k.D)
if err != nil {
return nil, err
}
addedKey := &AddedKey{PrivateKey: priv, Certificate: cert, Comment: k.Comments}
if err := setConstraints(addedKey, k.Constraints); err != nil {
return nil, err
}
return addedKey, nil
}
func (s *server) insertIdentity(req []byte) error {
var record struct {
Type string `sshtype:"17|25"`
Rest []byte `ssh:"rest"`
}
if err := ssh.Unmarshal(req, &record); err != nil {
return err
}
var addedKey *AddedKey
var err error
switch record.Type {
case ssh.KeyAlgoRSA:
addedKey, err = parseRSAKey(req)
case ssh.KeyAlgoDSA:
addedKey, err = parseDSAKey(req)
case ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521:
addedKey, err = parseECDSAKey(req)
case ssh.KeyAlgoED25519:
addedKey, err = parseEd25519Key(req)
case ssh.CertAlgoRSAv01:
addedKey, err = parseRSACert(req)
case ssh.CertAlgoDSAv01:
addedKey, err = parseDSACert(req)
case ssh.CertAlgoECDSA256v01, ssh.CertAlgoECDSA384v01, ssh.CertAlgoECDSA521v01:
addedKey, err = parseECDSACert(req)
case ssh.CertAlgoED25519v01:
addedKey, err = parseEd25519Cert(req)
default:
return fmt.Errorf("agent: not implemented: %q", record.Type)
}
if err != nil {
return err
}
return s.agent.Add(*addedKey)
}
// ServeAgent serves the agent protocol on the given connection. It
// returns when an I/O error occurs.
func ServeAgent(agent Agent, c io.ReadWriter) error {
s := &server{agent}
var length [4]byte
for {
if _, err := io.ReadFull(c, length[:]); err != nil {
return err
}
l := binary.BigEndian.Uint32(length[:])
if l == 0 {
return fmt.Errorf("agent: request size is 0")
}
if l > maxAgentResponseBytes {
// We also cap requests.
return fmt.Errorf("agent: request too large: %d", l)
}
req := make([]byte, l)
if _, err := io.ReadFull(c, req); err != nil {
return err
}
repData := s.processRequestBytes(req)
if len(repData) > maxAgentResponseBytes {
return fmt.Errorf("agent: reply too large: %d bytes", len(repData))
}
binary.BigEndian.PutUint32(length[:], uint32(len(repData)))
if _, err := c.Write(length[:]); err != nil {
return err
}
if _, err := c.Write(repData); err != nil {
return err
}
}
}

97
pkg/proto/ssh/buffer.go
View File

@ -1,97 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"io"
"sync"
)
// buffer provides a linked list buffer for data exchange
// between producer and consumer. Theoretically the buffer is
// of unlimited capacity as it does no allocation of its own.
type buffer struct {
// protects concurrent access to head, tail and closed
*sync.Cond
head *element // the buffer that will be read first
tail *element // the buffer that will be read last
closed bool
}
// An element represents a single link in a linked list.
type element struct {
buf []byte
next *element
}
// newBuffer returns an empty buffer that is not closed.
func newBuffer() *buffer {
e := new(element)
b := &buffer{
Cond: newCond(),
head: e,
tail: e,
}
return b
}
// write makes buf available for Read to receive.
// buf must not be modified after the call to write.
func (b *buffer) write(buf []byte) {
b.Cond.L.Lock()
e := &element{buf: buf}
b.tail.next = e
b.tail = e
b.Cond.Signal()
b.Cond.L.Unlock()
}
// eof closes the buffer. Reads from the buffer once all
// the data has been consumed will receive io.EOF.
func (b *buffer) eof() {
b.Cond.L.Lock()
b.closed = true
b.Cond.Signal()
b.Cond.L.Unlock()
}
// Read reads data from the internal buffer in buf. Reads will block
// if no data is available, or until the buffer is closed.
func (b *buffer) Read(buf []byte) (n int, err error) {
b.Cond.L.Lock()
defer b.Cond.L.Unlock()
for len(buf) > 0 {
// if there is data in b.head, copy it
if len(b.head.buf) > 0 {
r := copy(buf, b.head.buf)
buf, b.head.buf = buf[r:], b.head.buf[r:]
n += r
continue
}
// if there is a next buffer, make it the head
if len(b.head.buf) == 0 && b.head != b.tail {
b.head = b.head.next
continue
}
// if at least one byte has been copied, return
if n > 0 {
break
}
// if nothing was read, and there is nothing outstanding
// check to see if the buffer is closed.
if b.closed {
err = io.EOF
break
}
// out of buffers, wait for producer
b.Cond.Wait()
}
return
}

611
pkg/proto/ssh/certs.go
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@ -1,611 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
"net"
"sort"
"time"
)
// Certificate algorithm names from [PROTOCOL.certkeys]. These values can appear
// in Certificate.Type, PublicKey.Type, and ClientConfig.HostKeyAlgorithms.
// Unlike key algorithm names, these are not passed to AlgorithmSigner nor
// returned by MultiAlgorithmSigner and don't appear in the Signature.Format
// field.
const (
CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
CertAlgoSKECDSA256v01 = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com"
CertAlgoSKED25519v01 = "sk-ssh-ed25519-cert-v01@openssh.com"
// CertAlgoRSASHA256v01 and CertAlgoRSASHA512v01 can't appear as a
// Certificate.Type (or PublicKey.Type), but only in
// ClientConfig.HostKeyAlgorithms.
CertAlgoRSASHA256v01 = "rsa-sha2-256-cert-v01@openssh.com"
CertAlgoRSASHA512v01 = "rsa-sha2-512-cert-v01@openssh.com"
)
const (
// Deprecated: use CertAlgoRSAv01.
CertSigAlgoRSAv01 = CertAlgoRSAv01
// Deprecated: use CertAlgoRSASHA256v01.
CertSigAlgoRSASHA2256v01 = CertAlgoRSASHA256v01
// Deprecated: use CertAlgoRSASHA512v01.
CertSigAlgoRSASHA2512v01 = CertAlgoRSASHA512v01
)
// Certificate types distinguish between host and user
// certificates. The values can be set in the CertType field of
// Certificate.
const (
UserCert = 1
HostCert = 2
)
// Signature represents a cryptographic signature.
type Signature struct {
Format string
Blob []byte
Rest []byte `ssh:"rest"`
}
// CertTimeInfinity can be used for OpenSSHCertV01.ValidBefore to indicate that
// a certificate does not expire.
const CertTimeInfinity = 1<<64 - 1
// An Certificate represents an OpenSSH certificate as defined in
// [PROTOCOL.certkeys]?rev=1.8. The Certificate type implements the
// PublicKey interface, so it can be unmarshaled using
// ParsePublicKey.
type Certificate struct {
Nonce []byte
Key PublicKey
Serial uint64
CertType uint32
KeyId string
ValidPrincipals []string
ValidAfter uint64
ValidBefore uint64
Permissions
Reserved []byte
SignatureKey PublicKey
Signature *Signature
}
// genericCertData holds the key-independent part of the certificate data.
// Overall, certificates contain an nonce, public key fields and
// key-independent fields.
type genericCertData struct {
Serial uint64
CertType uint32
KeyId string
ValidPrincipals []byte
ValidAfter uint64
ValidBefore uint64
CriticalOptions []byte
Extensions []byte
Reserved []byte
SignatureKey []byte
Signature []byte
}
func marshalStringList(namelist []string) []byte {
var to []byte
for _, name := range namelist {
s := struct{ N string }{name}
to = append(to, Marshal(&s)...)
}
return to
}
type optionsTuple struct {
Key string
Value []byte
}
type optionsTupleValue struct {
Value string
}
// serialize a map of critical options or extensions
// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation,
// we need two length prefixes for a non-empty string value
func marshalTuples(tups map[string]string) []byte {
keys := make([]string, 0, len(tups))
for key := range tups {
keys = append(keys, key)
}
sort.Strings(keys)
var ret []byte
for _, key := range keys {
s := optionsTuple{Key: key}
if value := tups[key]; len(value) > 0 {
s.Value = Marshal(&optionsTupleValue{value})
}
ret = append(ret, Marshal(&s)...)
}
return ret
}
// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation,
// we need two length prefixes for a non-empty option value
func parseTuples(in []byte) (map[string]string, error) {
tups := map[string]string{}
var lastKey string
var haveLastKey bool
for len(in) > 0 {
var key, val, extra []byte
var ok bool
if key, in, ok = parseString(in); !ok {
return nil, errShortRead
}
keyStr := string(key)
// according to [PROTOCOL.certkeys], the names must be in
// lexical order.
if haveLastKey && keyStr <= lastKey {
return nil, fmt.Errorf("ssh: certificate options are not in lexical order")
}
lastKey, haveLastKey = keyStr, true
// the next field is a data field, which if non-empty has a string embedded
if val, in, ok = parseString(in); !ok {
return nil, errShortRead
}
if len(val) > 0 {
val, extra, ok = parseString(val)
if !ok {
return nil, errShortRead
}
if len(extra) > 0 {
return nil, fmt.Errorf("ssh: unexpected trailing data after certificate option value")
}
tups[keyStr] = string(val)
} else {
tups[keyStr] = ""
}
}
return tups, nil
}
func parseCert(in []byte, privAlgo string) (*Certificate, error) {
nonce, rest, ok := parseString(in)
if !ok {
return nil, errShortRead
}
key, rest, err := parsePubKey(rest, privAlgo)
if err != nil {
return nil, err
}
var g genericCertData
if err := Unmarshal(rest, &g); err != nil {
return nil, err
}
c := &Certificate{
Nonce: nonce,
Key: key,
Serial: g.Serial,
CertType: g.CertType,
KeyId: g.KeyId,
ValidAfter: g.ValidAfter,
ValidBefore: g.ValidBefore,
}
for principals := g.ValidPrincipals; len(principals) > 0; {
principal, rest, ok := parseString(principals)
if !ok {
return nil, errShortRead
}
c.ValidPrincipals = append(c.ValidPrincipals, string(principal))
principals = rest
}
c.CriticalOptions, err = parseTuples(g.CriticalOptions)
if err != nil {
return nil, err
}
c.Extensions, err = parseTuples(g.Extensions)
if err != nil {
return nil, err
}
c.Reserved = g.Reserved
k, err := ParsePublicKey(g.SignatureKey)
if err != nil {
return nil, err
}
c.SignatureKey = k
c.Signature, rest, ok = parseSignatureBody(g.Signature)
if !ok || len(rest) > 0 {
return nil, errors.New("ssh: signature parse error")
}
return c, nil
}
type openSSHCertSigner struct {
pub *Certificate
signer Signer
}
type algorithmOpenSSHCertSigner struct {
*openSSHCertSigner
algorithmSigner AlgorithmSigner
}
// NewCertSigner returns a Signer that signs with the given Certificate, whose
// private key is held by signer. It returns an error if the public key in cert
// doesn't match the key used by signer.
func NewCertSigner(cert *Certificate, signer Signer) (Signer, error) {
if !bytes.Equal(cert.Key.Marshal(), signer.PublicKey().Marshal()) {
return nil, errors.New("ssh: signer and cert have different public key")
}
switch s := signer.(type) {
case MultiAlgorithmSigner:
return &multiAlgorithmSigner{
AlgorithmSigner: &algorithmOpenSSHCertSigner{
&openSSHCertSigner{cert, signer}, s},
supportedAlgorithms: s.Algorithms(),
}, nil
case AlgorithmSigner:
return &algorithmOpenSSHCertSigner{
&openSSHCertSigner{cert, signer}, s}, nil
default:
return &openSSHCertSigner{cert, signer}, nil
}
}
func (s *openSSHCertSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
return s.signer.Sign(rand, data)
}
func (s *openSSHCertSigner) PublicKey() PublicKey {
return s.pub
}
func (s *algorithmOpenSSHCertSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) {
return s.algorithmSigner.SignWithAlgorithm(rand, data, algorithm)
}
const sourceAddressCriticalOption = "source-address"
// CertChecker does the work of verifying a certificate. Its methods
// can be plugged into ClientConfig.HostKeyCallback and
// ServerConfig.PublicKeyCallback. For the CertChecker to work,
// minimally, the IsAuthority callback should be set.
type CertChecker struct {
// SupportedCriticalOptions lists the CriticalOptions that the
// server application layer understands. These are only used
// for user certificates.
SupportedCriticalOptions []string
// IsUserAuthority should return true if the key is recognized as an
// authority for the given user certificate. This allows for
// certificates to be signed by other certificates. This must be set
// if this CertChecker will be checking user certificates.
IsUserAuthority func(auth PublicKey) bool
// IsHostAuthority should report whether the key is recognized as
// an authority for this host. This allows for certificates to be
// signed by other keys, and for those other keys to only be valid
// signers for particular hostnames. This must be set if this
// CertChecker will be checking host certificates.
IsHostAuthority func(auth PublicKey, address string) bool
// Clock is used for verifying time stamps. If nil, time.Now
// is used.
Clock func() time.Time
// UserKeyFallback is called when CertChecker.Authenticate encounters a
// public key that is not a certificate. It must implement validation
// of user keys or else, if nil, all such keys are rejected.
UserKeyFallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// HostKeyFallback is called when CertChecker.CheckHostKey encounters a
// public key that is not a certificate. It must implement host key
// validation or else, if nil, all such keys are rejected.
HostKeyFallback HostKeyCallback
// IsRevoked is called for each certificate so that revocation checking
// can be implemented. It should return true if the given certificate
// is revoked and false otherwise. If nil, no certificates are
// considered to have been revoked.
IsRevoked func(cert *Certificate) bool
}
// CheckHostKey checks a host key certificate. This method can be
// plugged into ClientConfig.HostKeyCallback.
func (c *CertChecker) CheckHostKey(addr string, remote net.Addr, key PublicKey) error {
cert, ok := key.(*Certificate)
if !ok {
if c.HostKeyFallback != nil {
return c.HostKeyFallback(addr, remote, key)
}
return errors.New("ssh: non-certificate host key")
}
if cert.CertType != HostCert {
return fmt.Errorf("ssh: certificate presented as a host key has type %d", cert.CertType)
}
if !c.IsHostAuthority(cert.SignatureKey, addr) {
return fmt.Errorf("ssh: no authorities for hostname: %v", addr)
}
hostname, _, err := net.SplitHostPort(addr)
if err != nil {
return err
}
// Pass hostname only as principal for host certificates (consistent with OpenSSH)
return c.CheckCert(hostname, cert)
}
// Authenticate checks a user certificate. Authenticate can be used as
// a value for ServerConfig.PublicKeyCallback.
func (c *CertChecker) Authenticate(conn ConnMetadata, pubKey PublicKey) (*Permissions, error) {
cert, ok := pubKey.(*Certificate)
if !ok {
if c.UserKeyFallback != nil {
return c.UserKeyFallback(conn, pubKey)
}
return nil, errors.New("ssh: normal key pairs not accepted")
}
if cert.CertType != UserCert {
return nil, fmt.Errorf("ssh: cert has type %d", cert.CertType)
}
if !c.IsUserAuthority(cert.SignatureKey) {
return nil, fmt.Errorf("ssh: certificate signed by unrecognized authority")
}
if err := c.CheckCert(conn.User(), cert); err != nil {
return nil, err
}
return &cert.Permissions, nil
}
// CheckCert checks CriticalOptions, ValidPrincipals, revocation, timestamp and
// the signature of the certificate.
func (c *CertChecker) CheckCert(principal string, cert *Certificate) error {
if c.IsRevoked != nil && c.IsRevoked(cert) {
return fmt.Errorf("ssh: certificate serial %d revoked", cert.Serial)
}
for opt := range cert.CriticalOptions {
// sourceAddressCriticalOption will be enforced by
// serverAuthenticate
if opt == sourceAddressCriticalOption {
continue
}
found := false
for _, supp := range c.SupportedCriticalOptions {
if supp == opt {
found = true
break
}
}
if !found {
return fmt.Errorf("ssh: unsupported critical option %q in certificate", opt)
}
}
if len(cert.ValidPrincipals) > 0 {
// By default, certs are valid for all users/hosts.
found := false
for _, p := range cert.ValidPrincipals {
if p == principal {
found = true
break
}
}
if !found {
return fmt.Errorf("ssh: principal %q not in the set of valid principals for given certificate: %q", principal, cert.ValidPrincipals)
}
}
clock := c.Clock
if clock == nil {
clock = time.Now
}
unixNow := clock().Unix()
if after := int64(cert.ValidAfter); after < 0 || unixNow < int64(cert.ValidAfter) {
return fmt.Errorf("ssh: cert is not yet valid")
}
if before := int64(cert.ValidBefore); cert.ValidBefore != uint64(CertTimeInfinity) && (unixNow >= before || before < 0) {
return fmt.Errorf("ssh: cert has expired")
}
if err := cert.SignatureKey.Verify(cert.bytesForSigning(), cert.Signature); err != nil {
return fmt.Errorf("ssh: certificate signature does not verify")
}
return nil
}
// SignCert signs the certificate with an authority, setting the Nonce,
// SignatureKey, and Signature fields. If the authority implements the
// MultiAlgorithmSigner interface the first algorithm in the list is used. This
// is useful if you want to sign with a specific algorithm.
func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
c.Nonce = make([]byte, 32)
if _, err := io.ReadFull(rand, c.Nonce); err != nil {
return err
}
c.SignatureKey = authority.PublicKey()
if v, ok := authority.(MultiAlgorithmSigner); ok {
if len(v.Algorithms()) == 0 {
return errors.New("the provided authority has no signature algorithm")
}
// Use the first algorithm in the list.
sig, err := v.SignWithAlgorithm(rand, c.bytesForSigning(), v.Algorithms()[0])
if err != nil {
return err
}
c.Signature = sig
return nil
} else if v, ok := authority.(AlgorithmSigner); ok && v.PublicKey().Type() == KeyAlgoRSA {
// Default to KeyAlgoRSASHA512 for ssh-rsa signers.
// TODO: consider using KeyAlgoRSASHA256 as default.
sig, err := v.SignWithAlgorithm(rand, c.bytesForSigning(), KeyAlgoRSASHA512)
if err != nil {
return err
}
c.Signature = sig
return nil
}
sig, err := authority.Sign(rand, c.bytesForSigning())
if err != nil {
return err
}
c.Signature = sig
return nil
}
// certKeyAlgoNames is a mapping from known certificate algorithm names to the
// corresponding public key signature algorithm.
//
// This map must be kept in sync with the one in agent/client.go.
var certKeyAlgoNames = map[string]string{
CertAlgoRSAv01: KeyAlgoRSA,
CertAlgoRSASHA256v01: KeyAlgoRSASHA256,
CertAlgoRSASHA512v01: KeyAlgoRSASHA512,
CertAlgoDSAv01: KeyAlgoDSA,
CertAlgoECDSA256v01: KeyAlgoECDSA256,
CertAlgoECDSA384v01: KeyAlgoECDSA384,
CertAlgoECDSA521v01: KeyAlgoECDSA521,
CertAlgoSKECDSA256v01: KeyAlgoSKECDSA256,
CertAlgoED25519v01: KeyAlgoED25519,
CertAlgoSKED25519v01: KeyAlgoSKED25519,
}
// underlyingAlgo returns the signature algorithm associated with algo (which is
// an advertised or negotiated public key or host key algorithm). These are
// usually the same, except for certificate algorithms.
func underlyingAlgo(algo string) string {
if a, ok := certKeyAlgoNames[algo]; ok {
return a
}
return algo
}
// certificateAlgo returns the certificate algorithms that uses the provided
// underlying signature algorithm.
func certificateAlgo(algo string) (certAlgo string, ok bool) {
for certName, algoName := range certKeyAlgoNames {
if algoName == algo {
return certName, true
}
}
return "", false
}
func (cert *Certificate) bytesForSigning() []byte {
c2 := *cert
c2.Signature = nil
out := c2.Marshal()
// Drop trailing signature length.
return out[:len(out)-4]
}
// Marshal serializes c into OpenSSH's wire format. It is part of the
// PublicKey interface.
func (c *Certificate) Marshal() []byte {
generic := genericCertData{
Serial: c.Serial,
CertType: c.CertType,
KeyId: c.KeyId,
ValidPrincipals: marshalStringList(c.ValidPrincipals),
ValidAfter: uint64(c.ValidAfter),
ValidBefore: uint64(c.ValidBefore),
CriticalOptions: marshalTuples(c.CriticalOptions),
Extensions: marshalTuples(c.Extensions),
Reserved: c.Reserved,
SignatureKey: c.SignatureKey.Marshal(),
}
if c.Signature != nil {
generic.Signature = Marshal(c.Signature)
}
genericBytes := Marshal(&generic)
keyBytes := c.Key.Marshal()
_, keyBytes, _ = parseString(keyBytes)
prefix := Marshal(&struct {
Name string
Nonce []byte
Key []byte `ssh:"rest"`
}{c.Type(), c.Nonce, keyBytes})
result := make([]byte, 0, len(prefix)+len(genericBytes))
result = append(result, prefix...)
result = append(result, genericBytes...)
return result
}
// Type returns the certificate algorithm name. It is part of the PublicKey interface.
func (c *Certificate) Type() string {
certName, ok := certificateAlgo(c.Key.Type())
if !ok {
panic("unknown certificate type for key type " + c.Key.Type())
}
return certName
}
// Verify verifies a signature against the certificate's public
// key. It is part of the PublicKey interface.
func (c *Certificate) Verify(data []byte, sig *Signature) error {
return c.Key.Verify(data, sig)
}
func parseSignatureBody(in []byte) (out *Signature, rest []byte, ok bool) {
format, in, ok := parseString(in)
if !ok {
return
}
out = &Signature{
Format: string(format),
}
if out.Blob, in, ok = parseString(in); !ok {
return
}
switch out.Format {
case KeyAlgoSKECDSA256, CertAlgoSKECDSA256v01, KeyAlgoSKED25519, CertAlgoSKED25519v01:
out.Rest = in
return out, nil, ok
}
return out, in, ok
}
func parseSignature(in []byte) (out *Signature, rest []byte, ok bool) {
sigBytes, rest, ok := parseString(in)
if !ok {
return
}
out, trailing, ok := parseSignatureBody(sigBytes)
if !ok || len(trailing) > 0 {
return nil, nil, false
}
return
}

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pkg/proto/ssh/channel.go
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@ -1,633 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"encoding/binary"
"errors"
"fmt"
"io"
"log"
"sync"
)
const (
minPacketLength = 9
// channelMaxPacket contains the maximum number of bytes that will be
// sent in a single packet. As per RFC 4253, section 6.1, 32k is also
// the minimum.
channelMaxPacket = 1 << 15
// We follow OpenSSH here.
channelWindowSize = 64 * channelMaxPacket
)
// NewChannel represents an incoming request to a channel. It must either be
// accepted for use by calling Accept, or rejected by calling Reject.
type NewChannel interface {
// Accept accepts the channel creation request. It returns the Channel
// and a Go channel containing SSH requests. The Go channel must be
// serviced otherwise the Channel will hang.
Accept() (Channel, <-chan *Request, error)
// Reject rejects the channel creation request. After calling
// this, no other methods on the Channel may be called.
Reject(reason RejectionReason, message string) error
// ChannelType returns the type of the channel, as supplied by the
// client.
ChannelType() string
// ExtraData returns the arbitrary payload for this channel, as supplied
// by the client. This data is specific to the channel type.
ExtraData() []byte
}
// A Channel is an ordered, reliable, flow-controlled, duplex stream
// that is multiplexed over an SSH connection.
type Channel interface {
// Read reads up to len(data) bytes from the channel.
Read(data []byte) (int, error)
// Write writes len(data) bytes to the channel.
Write(data []byte) (int, error)
// Close signals end of channel use. No data may be sent after this
// call.
Close() error
// CloseWrite signals the end of sending in-band
// data. Requests may still be sent, and the other side may
// still send data
CloseWrite() error
// SendRequest sends a channel request. If wantReply is true,
// it will wait for a reply and return the result as a
// boolean, otherwise the return value will be false. Channel
// requests are out-of-band messages so they may be sent even
// if the data stream is closed or blocked by flow control.
// If the channel is closed before a reply is returned, io.EOF
// is returned.
SendRequest(name string, wantReply bool, payload []byte) (bool, error)
// Stderr returns an io.ReadWriter that writes to this channel
// with the extended data type set to stderr. Stderr may
// safely be read and written from a different goroutine than
// Read and Write respectively.
Stderr() io.ReadWriter
}
// Request is a request sent outside of the normal stream of
// data. Requests can either be specific to an SSH channel, or they
// can be global.
type Request struct {
Type string
WantReply bool
Payload []byte
ch *channel
mux *mux
}
// Reply sends a response to a request. It must be called for all requests
// where WantReply is true and is a no-op otherwise. The payload argument is
// ignored for replies to channel-specific requests.
func (r *Request) Reply(ok bool, payload []byte) error {
if !r.WantReply {
return nil
}
if r.ch == nil {
return r.mux.ackRequest(ok, payload)
}
return r.ch.ackRequest(ok)
}
// RejectionReason is an enumeration used when rejecting channel creation
// requests. See RFC 4254, section 5.1.
type RejectionReason uint32
const (
Prohibited RejectionReason = iota + 1
ConnectionFailed
UnknownChannelType
ResourceShortage
)
// String converts the rejection reason to human readable form.
func (r RejectionReason) String() string {
switch r {
case Prohibited:
return "administratively prohibited"
case ConnectionFailed:
return "connect failed"
case UnknownChannelType:
return "unknown channel type"
case ResourceShortage:
return "resource shortage"
}
return fmt.Sprintf("unknown reason %d", int(r))
}
func min(a uint32, b int) uint32 {
if a < uint32(b) {
return a
}
return uint32(b)
}
type channelDirection uint8
const (
channelInbound channelDirection = iota
channelOutbound
)
// channel is an implementation of the Channel interface that works
// with the mux class.
type channel struct {
// R/O after creation
chanType string
extraData []byte
localId, remoteId uint32
// maxIncomingPayload and maxRemotePayload are the maximum
// payload sizes of normal and extended data packets for
// receiving and sending, respectively. The wire packet will
// be 9 or 13 bytes larger (excluding encryption overhead).
maxIncomingPayload uint32
maxRemotePayload uint32
mux *mux
// decided is set to true if an accept or reject message has been sent
// (for outbound channels) or received (for inbound channels).
decided bool
// direction contains either channelOutbound, for channels created
// locally, or channelInbound, for channels created by the peer.
direction channelDirection
// Pending internal channel messages.
msg chan interface{}
// Since requests have no ID, there can be only one request
// with WantReply=true outstanding. This lock is held by a
// goroutine that has such an outgoing request pending.
sentRequestMu sync.Mutex
incomingRequests chan *Request
sentEOF bool
// thread-safe data
remoteWin window
pending *buffer
extPending *buffer
// windowMu protects myWindow, the flow-control window.
windowMu sync.Mutex
myWindow uint32
// writeMu serializes calls to mux.conn.writePacket() and
// protects sentClose and packetPool. This mutex must be
// different from windowMu, as writePacket can block if there
// is a key exchange pending.
writeMu sync.Mutex
sentClose bool
// packetPool has a buffer for each extended channel ID to
// save allocations during writes.
packetPool map[uint32][]byte
}
// writePacket sends a packet. If the packet is a channel close, it updates
// sentClose. This method takes the lock c.writeMu.
func (ch *channel) writePacket(packet []byte) error {
ch.writeMu.Lock()
if ch.sentClose {
ch.writeMu.Unlock()
return io.EOF
}
ch.sentClose = (packet[0] == msgChannelClose)
err := ch.mux.conn.writePacket(packet)
ch.writeMu.Unlock()
return err
}
func (ch *channel) sendMessage(msg interface{}) error {
if debugMux {
log.Printf("send(%d): %#v", ch.mux.chanList.offset, msg)
}
p := Marshal(msg)
binary.BigEndian.PutUint32(p[1:], ch.remoteId)
return ch.writePacket(p)
}
// WriteExtended writes data to a specific extended stream. These streams are
// used, for example, for stderr.
func (ch *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) {
if ch.sentEOF {
return 0, io.EOF
}
// 1 byte message type, 4 bytes remoteId, 4 bytes data length
opCode := byte(msgChannelData)
headerLength := uint32(9)
if extendedCode > 0 {
headerLength += 4
opCode = msgChannelExtendedData
}
ch.writeMu.Lock()
packet := ch.packetPool[extendedCode]
// We don't remove the buffer from packetPool, so
// WriteExtended calls from different goroutines will be
// flagged as errors by the race detector.
ch.writeMu.Unlock()
for len(data) > 0 {
space := min(ch.maxRemotePayload, len(data))
if space, err = ch.remoteWin.reserve(space); err != nil {
return n, err
}
if want := headerLength + space; uint32(cap(packet)) < want {
packet = make([]byte, want)
} else {
packet = packet[:want]
}
todo := data[:space]
packet[0] = opCode
binary.BigEndian.PutUint32(packet[1:], ch.remoteId)
if extendedCode > 0 {
binary.BigEndian.PutUint32(packet[5:], uint32(extendedCode))
}
binary.BigEndian.PutUint32(packet[headerLength-4:], uint32(len(todo)))
copy(packet[headerLength:], todo)
if err = ch.writePacket(packet); err != nil {
return n, err
}
n += len(todo)
data = data[len(todo):]
}
ch.writeMu.Lock()
ch.packetPool[extendedCode] = packet
ch.writeMu.Unlock()
return n, err
}
func (ch *channel) handleData(packet []byte) error {
headerLen := 9
isExtendedData := packet[0] == msgChannelExtendedData
if isExtendedData {
headerLen = 13
}
if len(packet) < headerLen {
// malformed data packet
return parseError(packet[0])
}
var extended uint32
if isExtendedData {
extended = binary.BigEndian.Uint32(packet[5:])
}
length := binary.BigEndian.Uint32(packet[headerLen-4 : headerLen])
if length == 0 {
return nil
}
if length > ch.maxIncomingPayload {
// TODO(hanwen): should send Disconnect?
return errors.New("ssh: incoming packet exceeds maximum payload size")
}
data := packet[headerLen:]
if length != uint32(len(data)) {
return errors.New("ssh: wrong packet length")
}
ch.windowMu.Lock()
if ch.myWindow < length {
ch.windowMu.Unlock()
// TODO(hanwen): should send Disconnect with reason?
return errors.New("ssh: remote side wrote too much")
}
ch.myWindow -= length
ch.windowMu.Unlock()
if extended == 1 {
ch.extPending.write(data)
} else if extended > 0 {
// discard other extended data.
} else {
ch.pending.write(data)
}
return nil
}
func (c *channel) adjustWindow(n uint32) error {
c.windowMu.Lock()
// Since myWindow is managed on our side, and can never exceed
// the initial window setting, we don't worry about overflow.
c.myWindow += uint32(n)
c.windowMu.Unlock()
return c.sendMessage(windowAdjustMsg{
AdditionalBytes: uint32(n),
})
}
func (c *channel) ReadExtended(data []byte, extended uint32) (n int, err error) {
switch extended {
case 1:
n, err = c.extPending.Read(data)
case 0:
n, err = c.pending.Read(data)
default:
return 0, fmt.Errorf("ssh: extended code %d unimplemented", extended)
}
if n > 0 {
err = c.adjustWindow(uint32(n))
// sendWindowAdjust can return io.EOF if the remote
// peer has closed the connection, however we want to
// defer forwarding io.EOF to the caller of Read until
// the buffer has been drained.
if n > 0 && err == io.EOF {
err = nil
}
}
return n, err
}
func (c *channel) close() {
c.pending.eof()
c.extPending.eof()
close(c.msg)
close(c.incomingRequests)
c.writeMu.Lock()
// This is not necessary for a normal channel teardown, but if
// there was another error, it is.
c.sentClose = true
c.writeMu.Unlock()
// Unblock writers.
c.remoteWin.close()
}
// responseMessageReceived is called when a success or failure message is
// received on a channel to check that such a message is reasonable for the
// given channel.
func (ch *channel) responseMessageReceived() error {
if ch.direction == channelInbound {
return errors.New("ssh: channel response message received on inbound channel")
}
if ch.decided {
return errors.New("ssh: duplicate response received for channel")
}
ch.decided = true
return nil
}
func (ch *channel) handlePacket(packet []byte) error {
switch packet[0] {
case msgChannelData, msgChannelExtendedData:
return ch.handleData(packet)
case msgChannelClose:
ch.sendMessage(channelCloseMsg{PeersID: ch.remoteId})
ch.mux.chanList.remove(ch.localId)
ch.close()
return nil
case msgChannelEOF:
// RFC 4254 is mute on how EOF affects dataExt messages but
// it is logical to signal EOF at the same time.
ch.extPending.eof()
ch.pending.eof()
return nil
}
decoded, err := decode(packet)
if err != nil {
return err
}
switch msg := decoded.(type) {
case *channelOpenFailureMsg:
if err := ch.responseMessageReceived(); err != nil {
return err
}
ch.mux.chanList.remove(msg.PeersID)
ch.msg <- msg
case *channelOpenConfirmMsg:
if err := ch.responseMessageReceived(); err != nil {
return err
}
if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
return fmt.Errorf("ssh: invalid MaxPacketSize %d from peer", msg.MaxPacketSize)
}
ch.remoteId = msg.MyID
ch.maxRemotePayload = msg.MaxPacketSize
ch.remoteWin.add(msg.MyWindow)
ch.msg <- msg
case *windowAdjustMsg:
if !ch.remoteWin.add(msg.AdditionalBytes) {
return fmt.Errorf("ssh: invalid window update for %d bytes", msg.AdditionalBytes)
}
case *channelRequestMsg:
req := Request{
Type: msg.Request,
WantReply: msg.WantReply,
Payload: msg.RequestSpecificData,
ch: ch,
}
ch.incomingRequests <- &req
default:
ch.msg <- msg
}
return nil
}
func (m *mux) newChannel(chanType string, direction channelDirection, extraData []byte) *channel {
ch := &channel{
remoteWin: window{Cond: newCond()},
myWindow: channelWindowSize,
pending: newBuffer(),
extPending: newBuffer(),
direction: direction,
incomingRequests: make(chan *Request, chanSize),
msg: make(chan interface{}, chanSize),
chanType: chanType,
extraData: extraData,
mux: m,
packetPool: make(map[uint32][]byte),
}
ch.localId = m.chanList.add(ch)
return ch
}
var errUndecided = errors.New("ssh: must Accept or Reject channel")
var errDecidedAlready = errors.New("ssh: can call Accept or Reject only once")
type extChannel struct {
code uint32
ch *channel
}
func (e *extChannel) Write(data []byte) (n int, err error) {
return e.ch.WriteExtended(data, e.code)
}
func (e *extChannel) Read(data []byte) (n int, err error) {
return e.ch.ReadExtended(data, e.code)
}
func (ch *channel) Accept() (Channel, <-chan *Request, error) {
if ch.decided {
return nil, nil, errDecidedAlready
}
ch.maxIncomingPayload = channelMaxPacket
confirm := channelOpenConfirmMsg{
PeersID: ch.remoteId,
MyID: ch.localId,
MyWindow: ch.myWindow,
MaxPacketSize: ch.maxIncomingPayload,
}
ch.decided = true
if err := ch.sendMessage(confirm); err != nil {
return nil, nil, err
}
return ch, ch.incomingRequests, nil
}
func (ch *channel) Reject(reason RejectionReason, message string) error {
if ch.decided {
return errDecidedAlready
}
reject := channelOpenFailureMsg{
PeersID: ch.remoteId,
Reason: reason,
Message: message,
Language: "en",
}
ch.decided = true
return ch.sendMessage(reject)
}
func (ch *channel) Read(data []byte) (int, error) {
if !ch.decided {
return 0, errUndecided
}
return ch.ReadExtended(data, 0)
}
func (ch *channel) Write(data []byte) (int, error) {
if !ch.decided {
return 0, errUndecided
}
return ch.WriteExtended(data, 0)
}
func (ch *channel) CloseWrite() error {
if !ch.decided {
return errUndecided
}
ch.sentEOF = true
return ch.sendMessage(channelEOFMsg{
PeersID: ch.remoteId})
}
func (ch *channel) Close() error {
if !ch.decided {
return errUndecided
}
return ch.sendMessage(channelCloseMsg{
PeersID: ch.remoteId})
}
// Extended returns an io.ReadWriter that sends and receives data on the given,
// SSH extended stream. Such streams are used, for example, for stderr.
func (ch *channel) Extended(code uint32) io.ReadWriter {
if !ch.decided {
return nil
}
return &extChannel{code, ch}
}
func (ch *channel) Stderr() io.ReadWriter {
return ch.Extended(1)
}
func (ch *channel) SendRequest(name string, wantReply bool, payload []byte) (bool, error) {
if !ch.decided {
return false, errUndecided
}
if wantReply {
ch.sentRequestMu.Lock()
defer ch.sentRequestMu.Unlock()
}
msg := channelRequestMsg{
PeersID: ch.remoteId,
Request: name,
WantReply: wantReply,
RequestSpecificData: payload,
}
if err := ch.sendMessage(msg); err != nil {
return false, err
}
if wantReply {
m, ok := (<-ch.msg)
if !ok {
return false, io.EOF
}
switch m.(type) {
case *channelRequestFailureMsg:
return false, nil
case *channelRequestSuccessMsg:
return true, nil
default:
return false, fmt.Errorf("ssh: unexpected response to channel request: %#v", m)
}
}
return false, nil
}
// ackRequest either sends an ack or nack to the channel request.
func (ch *channel) ackRequest(ok bool) error {
if !ch.decided {
return errUndecided
}
var msg interface{}
if !ok {
msg = channelRequestFailureMsg{
PeersID: ch.remoteId,
}
} else {
msg = channelRequestSuccessMsg{
PeersID: ch.remoteId,
}
}
return ch.sendMessage(msg)
}
func (ch *channel) ChannelType() string {
return ch.chanType
}
func (ch *channel) ExtraData() []byte {
return ch.extraData
}

789
pkg/proto/ssh/cipher.go
View File

@ -1,789 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/rc4"
"crypto/subtle"
"encoding/binary"
"errors"
"fmt"
"hash"
"io"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh/internal/poly1305"
"golang.org/x/crypto/chacha20"
)
const (
packetSizeMultiple = 16 // TODO(huin) this should be determined by the cipher.
// RFC 4253 section 6.1 defines a minimum packet size of 32768 that implementations
// MUST be able to process (plus a few more kilobytes for padding and mac). The RFC
// indicates implementations SHOULD be able to handle larger packet sizes, but then
// waffles on about reasonable limits.
//
// OpenSSH caps their maxPacket at 256kB so we choose to do
// the same. maxPacket is also used to ensure that uint32
// length fields do not overflow, so it should remain well
// below 4G.
maxPacket = 256 * 1024
)
// noneCipher implements cipher.Stream and provides no encryption. It is used
// by the transport before the first key-exchange.
type noneCipher struct{}
func (c noneCipher) XORKeyStream(dst, src []byte) {
copy(dst, src)
}
func newAESCTR(key, iv []byte) (cipher.Stream, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
return cipher.NewCTR(c, iv), nil
}
func newRC4(key, iv []byte) (cipher.Stream, error) {
return rc4.NewCipher(key)
}
type cipherMode struct {
keySize int
ivSize int
create func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error)
}
func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
return func(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
stream, err := createFunc(key, iv)
if err != nil {
return nil, err
}
var streamDump []byte
if skip > 0 {
streamDump = make([]byte, 512)
}
for remainingToDump := skip; remainingToDump > 0; {
dumpThisTime := remainingToDump
if dumpThisTime > len(streamDump) {
dumpThisTime = len(streamDump)
}
stream.XORKeyStream(streamDump[:dumpThisTime], streamDump[:dumpThisTime])
remainingToDump -= dumpThisTime
}
mac := macModes[algs.MAC].new(macKey)
return &streamPacketCipher{
mac: mac,
etm: macModes[algs.MAC].etm,
macResult: make([]byte, mac.Size()),
cipher: stream,
}, nil
}
}
// cipherModes documents properties of supported ciphers. Ciphers not included
// are not supported and will not be negotiated, even if explicitly requested in
// ClientConfig.Crypto.Ciphers.
var cipherModes = map[string]*cipherMode{
// Ciphers from RFC 4344, which introduced many CTR-based ciphers. Algorithms
// are defined in the order specified in the RFC.
"aes128-ctr": {16, aes.BlockSize, streamCipherMode(0, newAESCTR)},
"aes192-ctr": {24, aes.BlockSize, streamCipherMode(0, newAESCTR)},
"aes256-ctr": {32, aes.BlockSize, streamCipherMode(0, newAESCTR)},
// Ciphers from RFC 4345, which introduces security-improved arcfour ciphers.
// They are defined in the order specified in the RFC.
"arcfour128": {16, 0, streamCipherMode(1536, newRC4)},
"arcfour256": {32, 0, streamCipherMode(1536, newRC4)},
// Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol.
// Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and
// RC4) has problems with weak keys, and should be used with caution."
// RFC 4345 introduces improved versions of Arcfour.
"arcfour": {16, 0, streamCipherMode(0, newRC4)},
// AEAD ciphers
gcm128CipherID: {16, 12, newGCMCipher},
gcm256CipherID: {32, 12, newGCMCipher},
chacha20Poly1305ID: {64, 0, newChaCha20Cipher},
// CBC mode is insecure and so is not included in the default config.
// (See https://www.ieee-security.org/TC/SP2013/papers/4977a526.pdf). If absolutely
// needed, it's possible to specify a custom Config to enable it.
// You should expect that an active attacker can recover plaintext if
// you do.
aes128cbcID: {16, aes.BlockSize, newAESCBCCipher},
// 3des-cbc is insecure and is not included in the default
// config.
tripledescbcID: {24, des.BlockSize, newTripleDESCBCCipher},
}
// prefixLen is the length of the packet prefix that contains the packet length
// and number of padding bytes.
const prefixLen = 5
// streamPacketCipher is a packetCipher using a stream cipher.
type streamPacketCipher struct {
mac hash.Hash
cipher cipher.Stream
etm bool
// The following members are to avoid per-packet allocations.
prefix [prefixLen]byte
seqNumBytes [4]byte
padding [2 * packetSizeMultiple]byte
packetData []byte
macResult []byte
}
// readCipherPacket reads and decrypt a single packet from the reader argument.
func (s *streamPacketCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) {
if _, err := io.ReadFull(r, s.prefix[:]); err != nil {
return nil, err
}
var encryptedPaddingLength [1]byte
if s.mac != nil && s.etm {
copy(encryptedPaddingLength[:], s.prefix[4:5])
s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5])
} else {
s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
}
length := binary.BigEndian.Uint32(s.prefix[0:4])
paddingLength := uint32(s.prefix[4])
var macSize uint32
if s.mac != nil {
s.mac.Reset()
binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
s.mac.Write(s.seqNumBytes[:])
if s.etm {
s.mac.Write(s.prefix[:4])
s.mac.Write(encryptedPaddingLength[:])
} else {
s.mac.Write(s.prefix[:])
}
macSize = uint32(s.mac.Size())
}
if length <= paddingLength+1 {
return nil, errors.New("ssh: invalid packet length, packet too small")
}
if length > maxPacket {
return nil, errors.New("ssh: invalid packet length, packet too large")
}
// the maxPacket check above ensures that length-1+macSize
// does not overflow.
if uint32(cap(s.packetData)) < length-1+macSize {
s.packetData = make([]byte, length-1+macSize)
} else {
s.packetData = s.packetData[:length-1+macSize]
}
if _, err := io.ReadFull(r, s.packetData); err != nil {
return nil, err
}
mac := s.packetData[length-1:]
data := s.packetData[:length-1]
if s.mac != nil && s.etm {
s.mac.Write(data)
}
s.cipher.XORKeyStream(data, data)
if s.mac != nil {
if !s.etm {
s.mac.Write(data)
}
s.macResult = s.mac.Sum(s.macResult[:0])
if subtle.ConstantTimeCompare(s.macResult, mac) != 1 {
return nil, errors.New("ssh: MAC failure")
}
}
return s.packetData[:length-paddingLength-1], nil
}
// writeCipherPacket encrypts and sends a packet of data to the writer argument
func (s *streamPacketCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
if len(packet) > maxPacket {
return errors.New("ssh: packet too large")
}
aadlen := 0
if s.mac != nil && s.etm {
// packet length is not encrypted for EtM modes
aadlen = 4
}
paddingLength := packetSizeMultiple - (prefixLen+len(packet)-aadlen)%packetSizeMultiple
if paddingLength < 4 {
paddingLength += packetSizeMultiple
}
length := len(packet) + 1 + paddingLength
binary.BigEndian.PutUint32(s.prefix[:], uint32(length))
s.prefix[4] = byte(paddingLength)
padding := s.padding[:paddingLength]
if _, err := io.ReadFull(rand, padding); err != nil {
return err
}
if s.mac != nil {
s.mac.Reset()
binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
s.mac.Write(s.seqNumBytes[:])
if s.etm {
// For EtM algorithms, the packet length must stay unencrypted,
// but the following data (padding length) must be encrypted
s.cipher.XORKeyStream(s.prefix[4:5], s.prefix[4:5])
}
s.mac.Write(s.prefix[:])
if !s.etm {
// For non-EtM algorithms, the algorithm is applied on unencrypted data
s.mac.Write(packet)
s.mac.Write(padding)
}
}
if !(s.mac != nil && s.etm) {
// For EtM algorithms, the padding length has already been encrypted
// and the packet length must remain unencrypted
s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
}
s.cipher.XORKeyStream(packet, packet)
s.cipher.XORKeyStream(padding, padding)
if s.mac != nil && s.etm {
// For EtM algorithms, packet and padding must be encrypted
s.mac.Write(packet)
s.mac.Write(padding)
}
if _, err := w.Write(s.prefix[:]); err != nil {
return err
}
if _, err := w.Write(packet); err != nil {
return err
}
if _, err := w.Write(padding); err != nil {
return err
}
if s.mac != nil {
s.macResult = s.mac.Sum(s.macResult[:0])
if _, err := w.Write(s.macResult); err != nil {
return err
}
}
return nil
}
type gcmCipher struct {
aead cipher.AEAD
prefix [4]byte
iv []byte
buf []byte
}
func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aead, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
return &gcmCipher{
aead: aead,
iv: iv,
}, nil
}
const gcmTagSize = 16
func (c *gcmCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
// Pad out to multiple of 16 bytes. This is different from the
// stream cipher because that encrypts the length too.
padding := byte(packetSizeMultiple - (1+len(packet))%packetSizeMultiple)
if padding < 4 {
padding += packetSizeMultiple
}
length := uint32(len(packet) + int(padding) + 1)
binary.BigEndian.PutUint32(c.prefix[:], length)
if _, err := w.Write(c.prefix[:]); err != nil {
return err
}
if cap(c.buf) < int(length) {
c.buf = make([]byte, length)
} else {
c.buf = c.buf[:length]
}
c.buf[0] = padding
copy(c.buf[1:], packet)
if _, err := io.ReadFull(rand, c.buf[1+len(packet):]); err != nil {
return err
}
c.buf = c.aead.Seal(c.buf[:0], c.iv, c.buf, c.prefix[:])
if _, err := w.Write(c.buf); err != nil {
return err
}
c.incIV()
return nil
}
func (c *gcmCipher) incIV() {
for i := 4 + 7; i >= 4; i-- {
c.iv[i]++
if c.iv[i] != 0 {
break
}
}
}
func (c *gcmCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) {
if _, err := io.ReadFull(r, c.prefix[:]); err != nil {
return nil, err
}
length := binary.BigEndian.Uint32(c.prefix[:])
if length > maxPacket {
return nil, errors.New("ssh: max packet length exceeded")
}
if cap(c.buf) < int(length+gcmTagSize) {
c.buf = make([]byte, length+gcmTagSize)
} else {
c.buf = c.buf[:length+gcmTagSize]
}
if _, err := io.ReadFull(r, c.buf); err != nil {
return nil, err
}
plain, err := c.aead.Open(c.buf[:0], c.iv, c.buf, c.prefix[:])
if err != nil {
return nil, err
}
c.incIV()
if len(plain) == 0 {
return nil, errors.New("ssh: empty packet")
}
padding := plain[0]
if padding < 4 {
// padding is a byte, so it automatically satisfies
// the maximum size, which is 255.
return nil, fmt.Errorf("ssh: illegal padding %d", padding)
}
if int(padding+1) >= len(plain) {
return nil, fmt.Errorf("ssh: padding %d too large", padding)
}
plain = plain[1 : length-uint32(padding)]
return plain, nil
}
// cbcCipher implements aes128-cbc cipher defined in RFC 4253 section 6.1
type cbcCipher struct {
mac hash.Hash
macSize uint32
decrypter cipher.BlockMode
encrypter cipher.BlockMode
// The following members are to avoid per-packet allocations.
seqNumBytes [4]byte
packetData []byte
macResult []byte
// Amount of data we should still read to hide which
// verification error triggered.
oracleCamouflage uint32
}
func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
cbc := &cbcCipher{
mac: macModes[algs.MAC].new(macKey),
decrypter: cipher.NewCBCDecrypter(c, iv),
encrypter: cipher.NewCBCEncrypter(c, iv),
packetData: make([]byte, 1024),
}
if cbc.mac != nil {
cbc.macSize = uint32(cbc.mac.Size())
}
return cbc, nil
}
func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
cbc, err := newCBCCipher(c, key, iv, macKey, algs)
if err != nil {
return nil, err
}
return cbc, nil
}
func newTripleDESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
c, err := des.NewTripleDESCipher(key)
if err != nil {
return nil, err
}
cbc, err := newCBCCipher(c, key, iv, macKey, algs)
if err != nil {
return nil, err
}
return cbc, nil
}
func maxUInt32(a, b int) uint32 {
if a > b {
return uint32(a)
}
return uint32(b)
}
const (
cbcMinPacketSizeMultiple = 8
cbcMinPacketSize = 16
cbcMinPaddingSize = 4
)
// cbcError represents a verification error that may leak information.
type cbcError string
func (e cbcError) Error() string { return string(e) }
func (c *cbcCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) {
p, err := c.readCipherPacketLeaky(seqNum, r)
if err != nil {
if _, ok := err.(cbcError); ok {
// Verification error: read a fixed amount of
// data, to make distinguishing between
// failing MAC and failing length check more
// difficult.
io.CopyN(io.Discard, r, int64(c.oracleCamouflage))
}
}
return p, err
}
func (c *cbcCipher) readCipherPacketLeaky(seqNum uint32, r io.Reader) ([]byte, error) {
blockSize := c.decrypter.BlockSize()
// Read the header, which will include some of the subsequent data in the
// case of block ciphers - this is copied back to the payload later.
// How many bytes of payload/padding will be read with this first read.
firstBlockLength := uint32((prefixLen + blockSize - 1) / blockSize * blockSize)
firstBlock := c.packetData[:firstBlockLength]
if _, err := io.ReadFull(r, firstBlock); err != nil {
return nil, err
}
c.oracleCamouflage = maxPacket + 4 + c.macSize - firstBlockLength
c.decrypter.CryptBlocks(firstBlock, firstBlock)
length := binary.BigEndian.Uint32(firstBlock[:4])
if length > maxPacket {
return nil, cbcError("ssh: packet too large")
}
if length+4 < maxUInt32(cbcMinPacketSize, blockSize) {
// The minimum size of a packet is 16 (or the cipher block size, whichever
// is larger) bytes.
return nil, cbcError("ssh: packet too small")
}
// The length of the packet (including the length field but not the MAC) must
// be a multiple of the block size or 8, whichever is larger.
if (length+4)%maxUInt32(cbcMinPacketSizeMultiple, blockSize) != 0 {
return nil, cbcError("ssh: invalid packet length multiple")
}
paddingLength := uint32(firstBlock[4])
if paddingLength < cbcMinPaddingSize || length <= paddingLength+1 {
return nil, cbcError("ssh: invalid packet length")
}
// Positions within the c.packetData buffer:
macStart := 4 + length
paddingStart := macStart - paddingLength
// Entire packet size, starting before length, ending at end of mac.
entirePacketSize := macStart + c.macSize
// Ensure c.packetData is large enough for the entire packet data.
if uint32(cap(c.packetData)) < entirePacketSize {
// Still need to upsize and copy, but this should be rare at runtime, only
// on upsizing the packetData buffer.
c.packetData = make([]byte, entirePacketSize)
copy(c.packetData, firstBlock)
} else {
c.packetData = c.packetData[:entirePacketSize]
}
n, err := io.ReadFull(r, c.packetData[firstBlockLength:])
if err != nil {
return nil, err
}
c.oracleCamouflage -= uint32(n)
remainingCrypted := c.packetData[firstBlockLength:macStart]
c.decrypter.CryptBlocks(remainingCrypted, remainingCrypted)
mac := c.packetData[macStart:]
if c.mac != nil {
c.mac.Reset()
binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum)
c.mac.Write(c.seqNumBytes[:])
c.mac.Write(c.packetData[:macStart])
c.macResult = c.mac.Sum(c.macResult[:0])
if subtle.ConstantTimeCompare(c.macResult, mac) != 1 {
return nil, cbcError("ssh: MAC failure")
}
}
return c.packetData[prefixLen:paddingStart], nil
}
func (c *cbcCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
effectiveBlockSize := maxUInt32(cbcMinPacketSizeMultiple, c.encrypter.BlockSize())
// Length of encrypted portion of the packet (header, payload, padding).
// Enforce minimum padding and packet size.
encLength := maxUInt32(prefixLen+len(packet)+cbcMinPaddingSize, cbcMinPaddingSize)
// Enforce block size.
encLength = (encLength + effectiveBlockSize - 1) / effectiveBlockSize * effectiveBlockSize
length := encLength - 4
paddingLength := int(length) - (1 + len(packet))
// Overall buffer contains: header, payload, padding, mac.
// Space for the MAC is reserved in the capacity but not the slice length.
bufferSize := encLength + c.macSize
if uint32(cap(c.packetData)) < bufferSize {
c.packetData = make([]byte, encLength, bufferSize)
} else {
c.packetData = c.packetData[:encLength]
}
p := c.packetData
// Packet header.
binary.BigEndian.PutUint32(p, length)
p = p[4:]
p[0] = byte(paddingLength)
// Payload.
p = p[1:]
copy(p, packet)
// Padding.
p = p[len(packet):]
if _, err := io.ReadFull(rand, p); err != nil {
return err
}
if c.mac != nil {
c.mac.Reset()
binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum)
c.mac.Write(c.seqNumBytes[:])
c.mac.Write(c.packetData)
// The MAC is now appended into the capacity reserved for it earlier.
c.packetData = c.mac.Sum(c.packetData)
}
c.encrypter.CryptBlocks(c.packetData[:encLength], c.packetData[:encLength])
if _, err := w.Write(c.packetData); err != nil {
return err
}
return nil
}
const chacha20Poly1305ID = "chacha20-poly1305@openssh.com"
// chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com
// AEAD, which is described here:
//
// https://tools.ietf.org/html/draft-josefsson-ssh-chacha20-poly1305-openssh-00
//
// the methods here also implement padding, which RFC 4253 Section 6
// also requires of stream ciphers.
type chacha20Poly1305Cipher struct {
lengthKey [32]byte
contentKey [32]byte
buf []byte
}
func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
if len(key) != 64 {
panic(len(key))
}
c := &chacha20Poly1305Cipher{
buf: make([]byte, 256),
}
copy(c.contentKey[:], key[:32])
copy(c.lengthKey[:], key[32:])
return c, nil
}
func (c *chacha20Poly1305Cipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error) {
nonce := make([]byte, 12)
binary.BigEndian.PutUint32(nonce[8:], seqNum)
s, err := chacha20.NewUnauthenticatedCipher(c.contentKey[:], nonce)
if err != nil {
return nil, err
}
var polyKey, discardBuf [32]byte
s.XORKeyStream(polyKey[:], polyKey[:])
s.XORKeyStream(discardBuf[:], discardBuf[:]) // skip the next 32 bytes
encryptedLength := c.buf[:4]
if _, err := io.ReadFull(r, encryptedLength); err != nil {
return nil, err
}
var lenBytes [4]byte
ls, err := chacha20.NewUnauthenticatedCipher(c.lengthKey[:], nonce)
if err != nil {
return nil, err
}
ls.XORKeyStream(lenBytes[:], encryptedLength)
length := binary.BigEndian.Uint32(lenBytes[:])
if length > maxPacket {
return nil, errors.New("ssh: invalid packet length, packet too large")
}
contentEnd := 4 + length
packetEnd := contentEnd + poly1305.TagSize
if uint32(cap(c.buf)) < packetEnd {
c.buf = make([]byte, packetEnd)
copy(c.buf[:], encryptedLength)
} else {
c.buf = c.buf[:packetEnd]
}
if _, err := io.ReadFull(r, c.buf[4:packetEnd]); err != nil {
return nil, err
}
var mac [poly1305.TagSize]byte
copy(mac[:], c.buf[contentEnd:packetEnd])
if !poly1305.Verify(&mac, c.buf[:contentEnd], &polyKey) {
return nil, errors.New("ssh: MAC failure")
}
plain := c.buf[4:contentEnd]
s.XORKeyStream(plain, plain)
if len(plain) == 0 {
return nil, errors.New("ssh: empty packet")
}
padding := plain[0]
if padding < 4 {
// padding is a byte, so it automatically satisfies
// the maximum size, which is 255.
return nil, fmt.Errorf("ssh: illegal padding %d", padding)
}
if int(padding)+1 >= len(plain) {
return nil, fmt.Errorf("ssh: padding %d too large", padding)
}
plain = plain[1 : len(plain)-int(padding)]
return plain, nil
}
func (c *chacha20Poly1305Cipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader, payload []byte) error {
nonce := make([]byte, 12)
binary.BigEndian.PutUint32(nonce[8:], seqNum)
s, err := chacha20.NewUnauthenticatedCipher(c.contentKey[:], nonce)
if err != nil {
return err
}
var polyKey, discardBuf [32]byte
s.XORKeyStream(polyKey[:], polyKey[:])
s.XORKeyStream(discardBuf[:], discardBuf[:]) // skip the next 32 bytes
// There is no blocksize, so fall back to multiple of 8 byte
// padding, as described in RFC 4253, Sec 6.
const packetSizeMultiple = 8
padding := packetSizeMultiple - (1+len(payload))%packetSizeMultiple
if padding < 4 {
padding += packetSizeMultiple
}
// size (4 bytes), padding (1), payload, padding, tag.
totalLength := 4 + 1 + len(payload) + padding + poly1305.TagSize
if cap(c.buf) < totalLength {
c.buf = make([]byte, totalLength)
} else {
c.buf = c.buf[:totalLength]
}
binary.BigEndian.PutUint32(c.buf, uint32(1+len(payload)+padding))
ls, err := chacha20.NewUnauthenticatedCipher(c.lengthKey[:], nonce)
if err != nil {
return err
}
ls.XORKeyStream(c.buf, c.buf[:4])
c.buf[4] = byte(padding)
copy(c.buf[5:], payload)
packetEnd := 5 + len(payload) + padding
if _, err := io.ReadFull(rand, c.buf[5+len(payload):packetEnd]); err != nil {
return err
}
s.XORKeyStream(c.buf[4:], c.buf[4:packetEnd])
var mac [poly1305.TagSize]byte
poly1305.Sum(&mac, c.buf[:packetEnd], &polyKey)
copy(c.buf[packetEnd:], mac[:])
if _, err := w.Write(c.buf); err != nil {
return err
}
return nil
}

282
pkg/proto/ssh/client.go
View File

@ -1,282 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"net"
"os"
"sync"
"time"
)
// Client implements a traditional SSH client that supports shells,
// subprocesses, TCP port/streamlocal forwarding and tunneled dialing.
type Client struct {
Conn
handleForwardsOnce sync.Once // guards calling (*Client).handleForwards
forwards forwardList // forwarded tcpip connections from the remote side
mu sync.Mutex
channelHandlers map[string]chan NewChannel
}
// HandleChannelOpen returns a channel on which NewChannel requests
// for the given type are sent. If the type already is being handled,
// nil is returned. The channel is closed when the connection is closed.
func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel {
c.mu.Lock()
defer c.mu.Unlock()
if c.channelHandlers == nil {
// The SSH channel has been closed.
c := make(chan NewChannel)
close(c)
return c
}
ch := c.channelHandlers[channelType]
if ch != nil {
return nil
}
ch = make(chan NewChannel, chanSize)
c.channelHandlers[channelType] = ch
return ch
}
// NewClient creates a Client on top of the given connection.
func NewClient(c Conn, chans <-chan NewChannel, reqs <-chan *Request) *Client {
conn := &Client{
Conn: c,
channelHandlers: make(map[string]chan NewChannel, 1),
}
go conn.handleGlobalRequests(reqs)
go conn.handleChannelOpens(chans)
go func() {
conn.Wait()
conn.forwards.closeAll()
}()
return conn
}
// NewClientConn establishes an authenticated SSH connection using c
// as the underlying transport. The Request and NewChannel channels
// must be serviced or the connection will hang.
func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan NewChannel, <-chan *Request, error) {
fullConf := *config
fullConf.SetDefaults()
if fullConf.HostKeyCallback == nil {
c.Close()
return nil, nil, nil, errors.New("ssh: must specify HostKeyCallback")
}
conn := &connection{
sshConn: sshConn{conn: c, user: fullConf.User},
}
if err := conn.clientHandshake(addr, &fullConf); err != nil {
c.Close()
return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %v", err)
}
conn.mux = newMux(conn.transport)
return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil
}
// clientHandshake performs the client side key exchange. See RFC 4253 Section
// 7.
func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) error {
if config.ClientVersion != "" {
c.clientVersion = []byte(config.ClientVersion)
} else {
c.clientVersion = []byte(packageVersion)
}
var err error
c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion)
if err != nil {
return err
}
c.transport = newClientTransport(
newTransport(c.sshConn.conn, config.Rand, true /* is client */),
c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr())
if err := c.transport.waitSession(); err != nil {
return err
}
c.sessionID = c.transport.getSessionID()
return c.clientAuthenticate(config)
}
// verifyHostKeySignature verifies the host key obtained in the key exchange.
// algo is the negotiated algorithm, and may be a certificate type.
func verifyHostKeySignature(hostKey PublicKey, algo string, result *kexResult) error {
sig, rest, ok := parseSignatureBody(result.Signature)
if len(rest) > 0 || !ok {
return errors.New("ssh: signature parse error")
}
if a := underlyingAlgo(algo); sig.Format != a {
return fmt.Errorf("ssh: invalid signature algorithm %q, expected %q", sig.Format, a)
}
return hostKey.Verify(result.H, sig)
}
// NewSession opens a new Session for this client. (A session is a remote
// execution of a program.)
func (c *Client) NewSession() (*Session, error) {
ch, in, err := c.OpenChannel("session", nil)
if err != nil {
return nil, err
}
return newSession(ch, in)
}
func (c *Client) handleGlobalRequests(incoming <-chan *Request) {
for r := range incoming {
// This handles keepalive messages and matches
// the behaviour of OpenSSH.
r.Reply(false, nil)
}
}
// handleChannelOpens channel open messages from the remote side.
func (c *Client) handleChannelOpens(in <-chan NewChannel) {
for ch := range in {
c.mu.Lock()
handler := c.channelHandlers[ch.ChannelType()]
c.mu.Unlock()
if handler != nil {
handler <- ch
} else {
ch.Reject(UnknownChannelType, fmt.Sprintf("unknown channel type: %v", ch.ChannelType()))
}
}
c.mu.Lock()
for _, ch := range c.channelHandlers {
close(ch)
}
c.channelHandlers = nil
c.mu.Unlock()
}
// Dial starts a client connection to the given SSH server. It is a
// convenience function that connects to the given network address,
// initiates the SSH handshake, and then sets up a Client. For access
// to incoming channels and requests, use net.Dial with NewClientConn
// instead.
func Dial(network, addr string, config *ClientConfig) (*Client, error) {
conn, err := net.DialTimeout(network, addr, config.Timeout)
if err != nil {
return nil, err
}
c, chans, reqs, err := NewClientConn(conn, addr, config)
if err != nil {
return nil, err
}
return NewClient(c, chans, reqs), nil
}
// HostKeyCallback is the function type used for verifying server
// keys. A HostKeyCallback must return nil if the host key is OK, or
// an error to reject it. It receives the hostname as passed to Dial
// or NewClientConn. The remote address is the RemoteAddr of the
// net.Conn underlying the SSH connection.
type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
// BannerCallback is the function type used for treat the banner sent by
// the server. A BannerCallback receives the message sent by the remote server.
type BannerCallback func(message string) error
// A ClientConfig structure is used to configure a Client. It must not be
// modified after having been passed to an SSH function.
type ClientConfig struct {
// Config contains configuration that is shared between clients and
// servers.
Config
// User contains the username to authenticate as.
User string
// Auth contains possible authentication methods to use with the
// server. Only the first instance of a particular RFC 4252 method will
// be used during authentication.
Auth []AuthMethod
// HostKeyCallback is called during the cryptographic
// handshake to validate the server's host key. The client
// configuration must supply this callback for the connection
// to succeed. The functions InsecureIgnoreHostKey or
// FixedHostKey can be used for simplistic host key checks.
HostKeyCallback HostKeyCallback
// BannerCallback is called during the SSH dance to display a custom
// server's message. The client configuration can supply this callback to
// handle it as wished. The function BannerDisplayStderr can be used for
// simplistic display on Stderr.
BannerCallback BannerCallback
// ClientVersion contains the version identification string that will
// be used for the connection. If empty, a reasonable default is used.
ClientVersion string
// HostKeyAlgorithms lists the public key algorithms that the client will
// accept from the server for host key authentication, in order of
// preference. If empty, a reasonable default is used. Any
// string returned from a PublicKey.Type method may be used, or
// any of the CertAlgo and KeyAlgo constants.
HostKeyAlgorithms []string
// Timeout is the maximum amount of time for the TCP connection to establish.
//
// A Timeout of zero means no timeout.
Timeout time.Duration
}
// InsecureIgnoreHostKey returns a function that can be used for
// ClientConfig.HostKeyCallback to accept any host key. It should
// not be used for production code.
func InsecureIgnoreHostKey() HostKeyCallback {
return func(hostname string, remote net.Addr, key PublicKey) error {
return nil
}
}
type fixedHostKey struct {
key PublicKey
}
func (f *fixedHostKey) check(hostname string, remote net.Addr, key PublicKey) error {
if f.key == nil {
return fmt.Errorf("ssh: required host key was nil")
}
if !bytes.Equal(key.Marshal(), f.key.Marshal()) {
return fmt.Errorf("ssh: host key mismatch")
}
return nil
}
// FixedHostKey returns a function for use in
// ClientConfig.HostKeyCallback to accept only a specific host key.
func FixedHostKey(key PublicKey) HostKeyCallback {
hk := &fixedHostKey{key}
return hk.check
}
// BannerDisplayStderr returns a function that can be used for
// ClientConfig.BannerCallback to display banners on os.Stderr.
func BannerDisplayStderr() BannerCallback {
return func(banner string) error {
_, err := os.Stderr.WriteString(banner)
return err
}
}

761
pkg/proto/ssh/client_auth.go
View File

@ -1,761 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
"strings"
)
type authResult int
const (
authFailure authResult = iota
authPartialSuccess
authSuccess
)
// clientAuthenticate authenticates with the remote server. See RFC 4252.
func (c *connection) clientAuthenticate(config *ClientConfig) error {
// initiate user auth session
if err := c.transport.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})); err != nil {
return err
}
packet, err := c.transport.readPacket()
if err != nil {
return err
}
// The server may choose to send a SSH_MSG_EXT_INFO at this point (if we
// advertised willingness to receive one, which we always do) or not. See
// RFC 8308, Section 2.4.
extensions := make(map[string][]byte)
if len(packet) > 0 && packet[0] == msgExtInfo {
var extInfo extInfoMsg
if err := Unmarshal(packet, &extInfo); err != nil {
return err
}
payload := extInfo.Payload
for i := uint32(0); i < extInfo.NumExtensions; i++ {
name, rest, ok := parseString(payload)
if !ok {
return parseError(msgExtInfo)
}
value, rest, ok := parseString(rest)
if !ok {
return parseError(msgExtInfo)
}
extensions[string(name)] = value
payload = rest
}
packet, err = c.transport.readPacket()
if err != nil {
return err
}
}
var serviceAccept serviceAcceptMsg
if err := Unmarshal(packet, &serviceAccept); err != nil {
return err
}
// during the authentication phase the client first attempts the "none" method
// then any untried methods suggested by the server.
var tried []string
var lastMethods []string
sessionID := c.transport.getSessionID()
for auth := AuthMethod(new(noneAuth)); auth != nil; {
ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand, extensions)
if err != nil {
// We return the error later if there is no other method left to
// try.
ok = authFailure
}
if ok == authSuccess {
// success
return nil
} else if ok == authFailure {
if m := auth.method(); !contains(tried, m) {
tried = append(tried, m)
}
}
if methods == nil {
methods = lastMethods
}
lastMethods = methods
auth = nil
findNext:
for _, a := range config.Auth {
candidateMethod := a.method()
if contains(tried, candidateMethod) {
continue
}
for _, meth := range methods {
if meth == candidateMethod {
auth = a
break findNext
}
}
}
if auth == nil && err != nil {
// We have an error and there are no other authentication methods to
// try, so we return it.
return err
}
}
return fmt.Errorf("ssh: unable to authenticate, attempted methods %v, no supported methods remain", tried)
}
func contains(list []string, e string) bool {
for _, s := range list {
if s == e {
return true
}
}
return false
}
// An AuthMethod represents an instance of an RFC 4252 authentication method.
type AuthMethod interface {
// auth authenticates user over transport t.
// Returns true if authentication is successful.
// If authentication is not successful, a []string of alternative
// method names is returned. If the slice is nil, it will be ignored
// and the previous set of possible methods will be reused.
auth(session []byte, user string, p packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error)
// method returns the RFC 4252 method name.
method() string
}
// "none" authentication, RFC 4252 section 5.2.
type noneAuth int
func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
if err := c.writePacket(Marshal(&userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: "none",
})); err != nil {
return authFailure, nil, err
}
return handleAuthResponse(c)
}
func (n *noneAuth) method() string {
return "none"
}
// passwordCallback is an AuthMethod that fetches the password through
// a function call, e.g. by prompting the user.
type passwordCallback func() (password string, err error)
func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
type passwordAuthMsg struct {
User string `sshtype:"50"`
Service string
Method string
Reply bool
Password string
}
pw, err := cb()
// REVIEW NOTE: is there a need to support skipping a password attempt?
// The program may only find out that the user doesn't have a password
// when prompting.
if err != nil {
return authFailure, nil, err
}
if err := c.writePacket(Marshal(&passwordAuthMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
Reply: false,
Password: pw,
})); err != nil {
return authFailure, nil, err
}
return handleAuthResponse(c)
}
func (cb passwordCallback) method() string {
return "password"
}
// Password returns an AuthMethod using the given password.
func Password(secret string) AuthMethod {
return passwordCallback(func() (string, error) { return secret, nil })
}
// PasswordCallback returns an AuthMethod that uses a callback for
// fetching a password.
func PasswordCallback(prompt func() (secret string, err error)) AuthMethod {
return passwordCallback(prompt)
}
type publickeyAuthMsg struct {
User string `sshtype:"50"`
Service string
Method string
// HasSig indicates to the receiver packet that the auth request is signed and
// should be used for authentication of the request.
HasSig bool
Algoname string
PubKey []byte
// Sig is tagged with "rest" so Marshal will exclude it during
// validateKey
Sig []byte `ssh:"rest"`
}
// publicKeyCallback is an AuthMethod that uses a set of key
// pairs for authentication.
type publicKeyCallback func() ([]Signer, error)
func (cb publicKeyCallback) method() string {
return "publickey"
}
func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (MultiAlgorithmSigner, string, error) {
var as MultiAlgorithmSigner
keyFormat := signer.PublicKey().Type()
// If the signer implements MultiAlgorithmSigner we use the algorithms it
// support, if it implements AlgorithmSigner we assume it supports all
// algorithms, otherwise only the key format one.
switch s := signer.(type) {
case MultiAlgorithmSigner:
as = s
case AlgorithmSigner:
as = &multiAlgorithmSigner{
AlgorithmSigner: s,
supportedAlgorithms: algorithmsForKeyFormat(underlyingAlgo(keyFormat)),
}
default:
as = &multiAlgorithmSigner{
AlgorithmSigner: algorithmSignerWrapper{signer},
supportedAlgorithms: []string{underlyingAlgo(keyFormat)},
}
}
getFallbackAlgo := func() (string, error) {
// Fallback to use if there is no "server-sig-algs" extension or a
// common algorithm cannot be found. We use the public key format if the
// MultiAlgorithmSigner supports it, otherwise we return an error.
if !contains(as.Algorithms(), underlyingAlgo(keyFormat)) {
return "", fmt.Errorf("ssh: no common public key signature algorithm, server only supports %q for key type %q, signer only supports %v",
underlyingAlgo(keyFormat), keyFormat, as.Algorithms())
}
return keyFormat, nil
}
extPayload, ok := extensions["server-sig-algs"]
if !ok {
// If there is no "server-sig-algs" extension use the fallback
// algorithm.
algo, err := getFallbackAlgo()
return as, algo, err
}
// The server-sig-algs extension only carries underlying signature
// algorithm, but we are trying to select a protocol-level public key
// algorithm, which might be a certificate type. Extend the list of server
// supported algorithms to include the corresponding certificate algorithms.
serverAlgos := strings.Split(string(extPayload), ",")
for _, algo := range serverAlgos {
if certAlgo, ok := certificateAlgo(algo); ok {
serverAlgos = append(serverAlgos, certAlgo)
}
}
// Filter algorithms based on those supported by MultiAlgorithmSigner.
var keyAlgos []string
for _, algo := range algorithmsForKeyFormat(keyFormat) {
if contains(as.Algorithms(), underlyingAlgo(algo)) {
keyAlgos = append(keyAlgos, algo)
}
}
algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos)
if err != nil {
// If there is no overlap, return the fallback algorithm to support
// servers that fail to list all supported algorithms.
algo, err := getFallbackAlgo()
return as, algo, err
}
return as, algo, nil
}
func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error) {
// Authentication is performed by sending an enquiry to test if a key is
// acceptable to the remote. If the key is acceptable, the client will
// attempt to authenticate with the valid key. If not the client will repeat
// the process with the remaining keys.
signers, err := cb()
if err != nil {
return authFailure, nil, err
}
var methods []string
var errSigAlgo error
for _, signer := range signers {
pub := signer.PublicKey()
as, algo, err := pickSignatureAlgorithm(signer, extensions)
if err != nil && errSigAlgo == nil {
// If we cannot negotiate a signature algorithm store the first
// error so we can return it to provide a more meaningful message if
// no other signers work.
errSigAlgo = err
continue
}
ok, err := validateKey(pub, algo, user, c)
if err != nil {
return authFailure, nil, err
}
if !ok {
continue
}
pubKey := pub.Marshal()
data := buildDataSignedForAuth(session, userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
}, algo, pubKey)
sign, err := as.SignWithAlgorithm(rand, data, underlyingAlgo(algo))
if err != nil {
return authFailure, nil, err
}
// manually wrap the serialized signature in a string
s := Marshal(sign)
sig := make([]byte, stringLength(len(s)))
marshalString(sig, s)
msg := publickeyAuthMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
HasSig: true,
Algoname: algo,
PubKey: pubKey,
Sig: sig,
}
p := Marshal(&msg)
if err := c.writePacket(p); err != nil {
return authFailure, nil, err
}
var success authResult
success, methods, err = handleAuthResponse(c)
if err != nil {
return authFailure, nil, err
}
// If authentication succeeds or the list of available methods does not
// contain the "publickey" method, do not attempt to authenticate with any
// other keys. According to RFC 4252 Section 7, the latter can occur when
// additional authentication methods are required.
if success == authSuccess || !contains(methods, cb.method()) {
return success, methods, err
}
}
return authFailure, methods, errSigAlgo
}
// validateKey validates the key provided is acceptable to the server.
func validateKey(key PublicKey, algo string, user string, c packetConn) (bool, error) {
pubKey := key.Marshal()
msg := publickeyAuthMsg{
User: user,
Service: serviceSSH,
Method: "publickey",
HasSig: false,
Algoname: algo,
PubKey: pubKey,
}
if err := c.writePacket(Marshal(&msg)); err != nil {
return false, err
}
return confirmKeyAck(key, algo, c)
}
func confirmKeyAck(key PublicKey, algo string, c packetConn) (bool, error) {
pubKey := key.Marshal()
for {
packet, err := c.readPacket()
if err != nil {
return false, err
}
switch packet[0] {
case msgUserAuthBanner:
if err := handleBannerResponse(c, packet); err != nil {
return false, err
}
case msgUserAuthPubKeyOk:
var msg userAuthPubKeyOkMsg
if err := Unmarshal(packet, &msg); err != nil {
return false, err
}
if msg.Algo != algo || !bytes.Equal(msg.PubKey, pubKey) {
return false, nil
}
return true, nil
case msgUserAuthFailure:
return false, nil
default:
return false, unexpectedMessageError(msgUserAuthPubKeyOk, packet[0])
}
}
}
// PublicKeys returns an AuthMethod that uses the given key
// pairs.
func PublicKeys(signers ...Signer) AuthMethod {
return publicKeyCallback(func() ([]Signer, error) { return signers, nil })
}
// PublicKeysCallback returns an AuthMethod that runs the given
// function to obtain a list of key pairs.
func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMethod {
return publicKeyCallback(getSigners)
}
// handleAuthResponse returns whether the preceding authentication request succeeded
// along with a list of remaining authentication methods to try next and
// an error if an unexpected response was received.
func handleAuthResponse(c packetConn) (authResult, []string, error) {
gotMsgExtInfo := false
for {
packet, err := c.readPacket()
if err != nil {
return authFailure, nil, err
}
switch packet[0] {
case msgUserAuthBanner:
if err := handleBannerResponse(c, packet); err != nil {
return authFailure, nil, err
}
case msgExtInfo:
// Ignore post-authentication RFC 8308 extensions, once.
if gotMsgExtInfo {
return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0])
}
gotMsgExtInfo = true
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
return authFailure, nil, err
}
if msg.PartialSuccess {
return authPartialSuccess, msg.Methods, nil
}
return authFailure, msg.Methods, nil
case msgUserAuthSuccess:
return authSuccess, nil, nil
default:
return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0])
}
}
}
func handleBannerResponse(c packetConn, packet []byte) error {
var msg userAuthBannerMsg
if err := Unmarshal(packet, &msg); err != nil {
return err
}
transport, ok := c.(*handshakeTransport)
if !ok {
return nil
}
if transport.bannerCallback != nil {
return transport.bannerCallback(msg.Message)
}
return nil
}
// KeyboardInteractiveChallenge should print questions, optionally
// disabling echoing (e.g. for passwords), and return all the answers.
// Challenge may be called multiple times in a single session. After
// successful authentication, the server may send a challenge with no
// questions, for which the name and instruction messages should be
// printed. RFC 4256 section 3.3 details how the UI should behave for
// both CLI and GUI environments.
type KeyboardInteractiveChallenge func(name, instruction string, questions []string, echos []bool) (answers []string, err error)
// KeyboardInteractive returns an AuthMethod using a prompt/response
// sequence controlled by the server.
func KeyboardInteractive(challenge KeyboardInteractiveChallenge) AuthMethod {
return challenge
}
func (cb KeyboardInteractiveChallenge) method() string {
return "keyboard-interactive"
}
func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
type initiateMsg struct {
User string `sshtype:"50"`
Service string
Method string
Language string
Submethods string
}
if err := c.writePacket(Marshal(&initiateMsg{
User: user,
Service: serviceSSH,
Method: "keyboard-interactive",
})); err != nil {
return authFailure, nil, err
}
gotMsgExtInfo := false
for {
packet, err := c.readPacket()
if err != nil {
return authFailure, nil, err
}
// like handleAuthResponse, but with less options.
switch packet[0] {
case msgUserAuthBanner:
if err := handleBannerResponse(c, packet); err != nil {
return authFailure, nil, err
}
continue
case msgExtInfo:
// Ignore post-authentication RFC 8308 extensions, once.
if gotMsgExtInfo {
return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
}
gotMsgExtInfo = true
continue
case msgUserAuthInfoRequest:
// OK
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
return authFailure, nil, err
}
if msg.PartialSuccess {
return authPartialSuccess, msg.Methods, nil
}
return authFailure, msg.Methods, nil
case msgUserAuthSuccess:
return authSuccess, nil, nil
default:
return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
}
var msg userAuthInfoRequestMsg
if err := Unmarshal(packet, &msg); err != nil {
return authFailure, nil, err
}
// Manually unpack the prompt/echo pairs.
rest := msg.Prompts
var prompts []string
var echos []bool
for i := 0; i < int(msg.NumPrompts); i++ {
prompt, r, ok := parseString(rest)
if !ok || len(r) == 0 {
return authFailure, nil, errors.New("ssh: prompt format error")
}
prompts = append(prompts, string(prompt))
echos = append(echos, r[0] != 0)
rest = r[1:]
}
if len(rest) != 0 {
return authFailure, nil, errors.New("ssh: extra data following keyboard-interactive pairs")
}
answers, err := cb(msg.Name, msg.Instruction, prompts, echos)
if err != nil {
return authFailure, nil, err
}
if len(answers) != len(prompts) {
return authFailure, nil, fmt.Errorf("ssh: incorrect number of answers from keyboard-interactive callback %d (expected %d)", len(answers), len(prompts))
}
responseLength := 1 + 4
for _, a := range answers {
responseLength += stringLength(len(a))
}
serialized := make([]byte, responseLength)
p := serialized
p[0] = msgUserAuthInfoResponse
p = p[1:]
p = marshalUint32(p, uint32(len(answers)))
for _, a := range answers {
p = marshalString(p, []byte(a))
}
if err := c.writePacket(serialized); err != nil {
return authFailure, nil, err
}
}
}
type retryableAuthMethod struct {
authMethod AuthMethod
maxTries int
}
func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (ok authResult, methods []string, err error) {
for i := 0; r.maxTries <= 0 || i < r.maxTries; i++ {
ok, methods, err = r.authMethod.auth(session, user, c, rand, extensions)
if ok != authFailure || err != nil { // either success, partial success or error terminate
return ok, methods, err
}
}
return ok, methods, err
}
func (r *retryableAuthMethod) method() string {
return r.authMethod.method()
}
// RetryableAuthMethod is a decorator for other auth methods enabling them to
// be retried up to maxTries before considering that AuthMethod itself failed.
// If maxTries is <= 0, will retry indefinitely
//
// This is useful for interactive clients using challenge/response type
// authentication (e.g. Keyboard-Interactive, Password, etc) where the user
// could mistype their response resulting in the server issuing a
// SSH_MSG_USERAUTH_FAILURE (rfc4252 #8 [password] and rfc4256 #3.4
// [keyboard-interactive]); Without this decorator, the non-retryable
// AuthMethod would be removed from future consideration, and never tried again
// (and so the user would never be able to retry their entry).
func RetryableAuthMethod(auth AuthMethod, maxTries int) AuthMethod {
return &retryableAuthMethod{authMethod: auth, maxTries: maxTries}
}
// GSSAPIWithMICAuthMethod is an AuthMethod with "gssapi-with-mic" authentication.
// See RFC 4462 section 3
// gssAPIClient is implementation of the GSSAPIClient interface, see the definition of the interface for details.
// target is the server host you want to log in to.
func GSSAPIWithMICAuthMethod(gssAPIClient GSSAPIClient, target string) AuthMethod {
if gssAPIClient == nil {
panic("gss-api client must be not nil with enable gssapi-with-mic")
}
return &gssAPIWithMICCallback{gssAPIClient: gssAPIClient, target: target}
}
type gssAPIWithMICCallback struct {
gssAPIClient GSSAPIClient
target string
}
func (g *gssAPIWithMICCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
m := &userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: g.method(),
}
// The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST.
// See RFC 4462 section 3.2.
m.Payload = appendU32(m.Payload, 1)
m.Payload = appendString(m.Payload, string(krb5OID))
if err := c.writePacket(Marshal(m)); err != nil {
return authFailure, nil, err
}
// The server responds to the SSH_MSG_USERAUTH_REQUEST with either an
// SSH_MSG_USERAUTH_FAILURE if none of the mechanisms are supported or
// with an SSH_MSG_USERAUTH_GSSAPI_RESPONSE.
// See RFC 4462 section 3.3.
// OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication,so I don't want to check
// selected mech if it is valid.
packet, err := c.readPacket()
if err != nil {
return authFailure, nil, err
}
userAuthGSSAPIResp := &userAuthGSSAPIResponse{}
if err := Unmarshal(packet, userAuthGSSAPIResp); err != nil {
return authFailure, nil, err
}
// Start the loop into the exchange token.
// See RFC 4462 section 3.4.
var token []byte
defer g.gssAPIClient.DeleteSecContext()
for {
// Initiates the establishment of a security context between the application and a remote peer.
nextToken, needContinue, err := g.gssAPIClient.InitSecContext("host@"+g.target, token, false)
if err != nil {
return authFailure, nil, err
}
if len(nextToken) > 0 {
if err := c.writePacket(Marshal(&userAuthGSSAPIToken{
Token: nextToken,
})); err != nil {
return authFailure, nil, err
}
}
if !needContinue {
break
}
packet, err = c.readPacket()
if err != nil {
return authFailure, nil, err
}
switch packet[0] {
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
return authFailure, nil, err
}
if msg.PartialSuccess {
return authPartialSuccess, msg.Methods, nil
}
return authFailure, msg.Methods, nil
case msgUserAuthGSSAPIError:
userAuthGSSAPIErrorResp := &userAuthGSSAPIError{}
if err := Unmarshal(packet, userAuthGSSAPIErrorResp); err != nil {
return authFailure, nil, err
}
return authFailure, nil, fmt.Errorf("GSS-API Error:\n"+
"Major Status: %d\n"+
"Minor Status: %d\n"+
"Error Message: %s\n", userAuthGSSAPIErrorResp.MajorStatus, userAuthGSSAPIErrorResp.MinorStatus,
userAuthGSSAPIErrorResp.Message)
case msgUserAuthGSSAPIToken:
userAuthGSSAPITokenReq := &userAuthGSSAPIToken{}
if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil {
return authFailure, nil, err
}
token = userAuthGSSAPITokenReq.Token
}
}
// Binding Encryption Keys.
// See RFC 4462 section 3.5.
micField := buildMIC(string(session), user, "ssh-connection", "gssapi-with-mic")
micToken, err := g.gssAPIClient.GetMIC(micField)
if err != nil {
return authFailure, nil, err
}
if err := c.writePacket(Marshal(&userAuthGSSAPIMIC{
MIC: micToken,
})); err != nil {
return authFailure, nil, err
}
return handleAuthResponse(c)
}
func (g *gssAPIWithMICCallback) method() string {
return "gssapi-with-mic"
}

468
pkg/proto/ssh/common.go
View File

@ -1,468 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto"
"crypto/rand"
"fmt"
"io"
"math"
"sync"
_ "crypto/sha1"
_ "crypto/sha256"
_ "crypto/sha512"
)
// These are string constants in the SSH protocol.
const (
compressionNone = "none"
serviceUserAuth = "ssh-userauth"
serviceSSH = "ssh-connection"
)
// supportedCiphers lists ciphers we support but might not recommend.
var supportedCiphers = []string{
"aes128-ctr", "aes192-ctr", "aes256-ctr",
"aes128-gcm@openssh.com", gcm256CipherID,
chacha20Poly1305ID,
"arcfour256", "arcfour128", "arcfour",
aes128cbcID,
tripledescbcID,
}
// preferredCiphers specifies the default preference for ciphers.
var preferredCiphers = []string{
"aes128-gcm@openssh.com", gcm256CipherID,
chacha20Poly1305ID,
"aes128-ctr", "aes192-ctr", "aes256-ctr",
}
// supportedKexAlgos specifies the supported key-exchange algorithms in
// preference order.
var supportedKexAlgos = []string{
kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
// P384 and P521 are not constant-time yet, but since we don't
// reuse ephemeral keys, using them for ECDH should be OK.
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1,
kexAlgoDH1SHA1,
}
// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden
// for the server half.
var serverForbiddenKexAlgos = map[string]struct{}{
kexAlgoDHGEXSHA1: {}, // server half implementation is only minimal to satisfy the automated tests
kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests
}
// preferredKexAlgos specifies the default preference for key-exchange
// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm
// is disabled by default because it is a bit slower than the others.
var preferredKexAlgos = []string{
kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA256, kexAlgoDH14SHA1,
}
// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods
// of authenticating servers) in preference order.
var supportedHostKeyAlgos = []string{
CertAlgoRSASHA256v01, CertAlgoRSASHA512v01,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSASHA256, KeyAlgoRSASHA512,
KeyAlgoRSA, KeyAlgoDSA,
KeyAlgoED25519,
}
// supportedMACs specifies a default set of MAC algorithms in preference order.
// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
// because they have reached the end of their useful life.
var supportedMACs = []string{
"hmac-sha2-256-etm@openssh.com", "hmac-sha2-512-etm@openssh.com", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96",
}
var supportedCompressions = []string{compressionNone}
// hashFuncs keeps the mapping of supported signature algorithms to their
// respective hashes needed for signing and verification.
var hashFuncs = map[string]crypto.Hash{
KeyAlgoRSA: crypto.SHA1,
KeyAlgoRSASHA256: crypto.SHA256,
KeyAlgoRSASHA512: crypto.SHA512,
KeyAlgoDSA: crypto.SHA1,
KeyAlgoECDSA256: crypto.SHA256,
KeyAlgoECDSA384: crypto.SHA384,
KeyAlgoECDSA521: crypto.SHA512,
// KeyAlgoED25519 doesn't pre-hash.
KeyAlgoSKECDSA256: crypto.SHA256,
KeyAlgoSKED25519: crypto.SHA256,
}
// algorithmsForKeyFormat returns the supported signature algorithms for a given
// public key format (PublicKey.Type), in order of preference. See RFC 8332,
// Section 2. See also the note in sendKexInit on backwards compatibility.
func algorithmsForKeyFormat(keyFormat string) []string {
switch keyFormat {
case KeyAlgoRSA:
return []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA}
case CertAlgoRSAv01:
return []string{CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, CertAlgoRSAv01}
default:
return []string{keyFormat}
}
}
// isRSA returns whether algo is a supported RSA algorithm, including certificate
// algorithms.
func isRSA(algo string) bool {
algos := algorithmsForKeyFormat(KeyAlgoRSA)
return contains(algos, underlyingAlgo(algo))
}
// supportedPubKeyAuthAlgos specifies the supported client public key
// authentication algorithms. Note that this doesn't include certificate types
// since those use the underlying algorithm. This list is sent to the client if
// it supports the server-sig-algs extension. Order is irrelevant.
var supportedPubKeyAuthAlgos = []string{
KeyAlgoED25519,
KeyAlgoSKED25519, KeyAlgoSKECDSA256,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA,
KeyAlgoDSA,
}
// unexpectedMessageError results when the SSH message that we received didn't
// match what we wanted.
func unexpectedMessageError(expected, got uint8) error {
return fmt.Errorf("ssh: unexpected message type %d (expected %d)", got, expected)
}
// parseError results from a malformed SSH message.
func parseError(tag uint8) error {
return fmt.Errorf("ssh: parse error in message type %d", tag)
}
func findCommon(what string, client []string, server []string) (common string, err error) {
for _, c := range client {
for _, s := range server {
if c == s {
return c, nil
}
}
}
return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server)
}
// directionAlgorithms records algorithm choices in one direction (either read or write)
type directionAlgorithms struct {
Cipher string
MAC string
Compression string
}
// rekeyBytes returns a rekeying intervals in bytes.
func (a *directionAlgorithms) rekeyBytes() int64 {
// According to RFC 4344 block ciphers should rekey after
// 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is
// 128.
switch a.Cipher {
case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcm128CipherID, gcm256CipherID, aes128cbcID:
return 16 * (1 << 32)
}
// For others, stick with RFC 4253 recommendation to rekey after 1 Gb of data.
return 1 << 30
}
var aeadCiphers = map[string]bool{
gcm128CipherID: true,
gcm256CipherID: true,
chacha20Poly1305ID: true,
}
type algorithms struct {
kex string
hostKey string
w directionAlgorithms
r directionAlgorithms
}
func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) {
result := &algorithms{}
result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos)
if err != nil {
return
}
result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos)
if err != nil {
return
}
stoc, ctos := &result.w, &result.r
if isClient {
ctos, stoc = stoc, ctos
}
ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer)
if err != nil {
return
}
stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient)
if err != nil {
return
}
if !aeadCiphers[ctos.Cipher] {
ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
if err != nil {
return
}
}
if !aeadCiphers[stoc.Cipher] {
stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
if err != nil {
return
}
}
ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
if err != nil {
return
}
stoc.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient)
if err != nil {
return
}
return result, nil
}
// If rekeythreshold is too small, we can't make any progress sending
// stuff.
const minRekeyThreshold uint64 = 256
// Config contains configuration data common to both ServerConfig and
// ClientConfig.
type Config struct {
// Rand provides the source of entropy for cryptographic
// primitives. If Rand is nil, the cryptographic random reader
// in package crypto/rand will be used.
Rand io.Reader
// The maximum number of bytes sent or received after which a
// new key is negotiated. It must be at least 256. If
// unspecified, a size suitable for the chosen cipher is used.
RekeyThreshold uint64
// The allowed key exchanges algorithms. If unspecified then a default set
// of algorithms is used. Unsupported values are silently ignored.
KeyExchanges []string
// The allowed cipher algorithms. If unspecified then a sensible default is
// used. Unsupported values are silently ignored.
Ciphers []string
// The allowed MAC algorithms. If unspecified then a sensible default is
// used. Unsupported values are silently ignored.
MACs []string
}
// SetDefaults sets sensible values for unset fields in config. This is
// exported for testing: Configs passed to SSH functions are copied and have
// default values set automatically.
func (c *Config) SetDefaults() {
if c.Rand == nil {
c.Rand = rand.Reader
}
if c.Ciphers == nil {
c.Ciphers = preferredCiphers
}
var ciphers []string
for _, c := range c.Ciphers {
if cipherModes[c] != nil {
// Ignore the cipher if we have no cipherModes definition.
ciphers = append(ciphers, c)
}
}
c.Ciphers = ciphers
if c.KeyExchanges == nil {
c.KeyExchanges = preferredKexAlgos
}
var kexs []string
for _, k := range c.KeyExchanges {
if kexAlgoMap[k] != nil {
// Ignore the KEX if we have no kexAlgoMap definition.
kexs = append(kexs, k)
}
}
c.KeyExchanges = kexs
if c.MACs == nil {
c.MACs = supportedMACs
}
var macs []string
for _, m := range c.MACs {
if macModes[m] != nil {
// Ignore the MAC if we have no macModes definition.
macs = append(macs, m)
}
}
c.MACs = macs
if c.RekeyThreshold == 0 {
// cipher specific default
} else if c.RekeyThreshold < minRekeyThreshold {
c.RekeyThreshold = minRekeyThreshold
} else if c.RekeyThreshold >= math.MaxInt64 {
// Avoid weirdness if somebody uses -1 as a threshold.
c.RekeyThreshold = math.MaxInt64
}
}
// buildDataSignedForAuth returns the data that is signed in order to prove
// possession of a private key. See RFC 4252, section 7. algo is the advertised
// algorithm, and may be a certificate type.
func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo string, pubKey []byte) []byte {
data := struct {
Session []byte
Type byte
User string
Service string
Method string
Sign bool
Algo string
PubKey []byte
}{
sessionID,
msgUserAuthRequest,
req.User,
req.Service,
req.Method,
true,
algo,
pubKey,
}
return Marshal(data)
}
func appendU16(buf []byte, n uint16) []byte {
return append(buf, byte(n>>8), byte(n))
}
func appendU32(buf []byte, n uint32) []byte {
return append(buf, byte(n>>24), byte(n>>16), byte(n>>8), byte(n))
}
func appendU64(buf []byte, n uint64) []byte {
return append(buf,
byte(n>>56), byte(n>>48), byte(n>>40), byte(n>>32),
byte(n>>24), byte(n>>16), byte(n>>8), byte(n))
}
func appendInt(buf []byte, n int) []byte {
return appendU32(buf, uint32(n))
}
func appendString(buf []byte, s string) []byte {
buf = appendU32(buf, uint32(len(s)))
buf = append(buf, s...)
return buf
}
func appendBool(buf []byte, b bool) []byte {
if b {
return append(buf, 1)
}
return append(buf, 0)
}
// newCond is a helper to hide the fact that there is no usable zero
// value for sync.Cond.
func newCond() *sync.Cond { return sync.NewCond(new(sync.Mutex)) }
// window represents the buffer available to clients
// wishing to write to a channel.
type window struct {
*sync.Cond
win uint32 // RFC 4254 5.2 says the window size can grow to 2^32-1
writeWaiters int
closed bool
}
// add adds win to the amount of window available
// for consumers.
func (w *window) add(win uint32) bool {
// a zero sized window adjust is a noop.
if win == 0 {
return true
}
w.L.Lock()
if w.win+win < win {
w.L.Unlock()
return false
}
w.win += win
// It is unusual that multiple goroutines would be attempting to reserve
// window space, but not guaranteed. Use broadcast to notify all waiters
// that additional window is available.
w.Broadcast()
w.L.Unlock()
return true
}
// close sets the window to closed, so all reservations fail
// immediately.
func (w *window) close() {
w.L.Lock()
w.closed = true
w.Broadcast()
w.L.Unlock()
}
// reserve reserves win from the available window capacity.
// If no capacity remains, reserve will block. reserve may
// return less than requested.
func (w *window) reserve(win uint32) (uint32, error) {
var err error
w.L.Lock()
w.writeWaiters++
w.Broadcast()
for w.win == 0 && !w.closed {
w.Wait()
}
w.writeWaiters--
if w.win < win {
win = w.win
}
w.win -= win
if w.closed {
err = io.EOF
}
w.L.Unlock()
return win, err
}
// waitWriterBlocked waits until some goroutine is blocked for further
// writes. It is used in tests only.
func (w *window) waitWriterBlocked() {
w.Cond.L.Lock()
for w.writeWaiters == 0 {
w.Cond.Wait()
}
w.Cond.L.Unlock()
}

143
pkg/proto/ssh/connection.go
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@ -1,143 +0,0 @@
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"fmt"
"net"
)
// OpenChannelError is returned if the other side rejects an
// OpenChannel request.
type OpenChannelError struct {
Reason RejectionReason
Message string
}
func (e *OpenChannelError) Error() string {
return fmt.Sprintf("ssh: rejected: %s (%s)", e.Reason, e.Message)
}
// ConnMetadata holds metadata for the connection.
type ConnMetadata interface {
// User returns the user ID for this connection.
User() string
// SessionID returns the session hash, also denoted by H.
SessionID() []byte
// ClientVersion returns the client's version string as hashed
// into the session ID.
ClientVersion() []byte
// ServerVersion returns the server's version string as hashed
// into the session ID.
ServerVersion() []byte
// RemoteAddr returns the remote address for this connection.
RemoteAddr() net.Addr
// LocalAddr returns the local address for this connection.
LocalAddr() net.Addr
}
// Conn represents an SSH connection for both server and client roles.
// Conn is the basis for implementing an application layer, such
// as ClientConn, which implements the traditional shell access for
// clients.
type Conn interface {
ConnMetadata
// SendRequest sends a global request, and returns the
// reply. If wantReply is true, it returns the response status
// and payload. See also RFC 4254, section 4.
SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error)
// OpenChannel tries to open an channel. If the request is
// rejected, it returns *OpenChannelError. On success it returns
// the SSH Channel and a Go channel for incoming, out-of-band
// requests. The Go channel must be serviced, or the
// connection will hang.
OpenChannel(name string, data []byte) (Channel, <-chan *Request, error)
// Close closes the underlying network connection
Close() error
// Wait blocks until the connection has shut down, and returns the
// error causing the shutdown.
Wait() error
// TODO(hanwen): consider exposing:
// RequestKeyChange
// Disconnect
}
// DiscardRequests consumes and rejects all requests from the
// passed-in channel.
func DiscardRequests(in <-chan *Request) {
for req := range in {
if req.WantReply {
req.Reply(false, nil)
}
}
}
// A connection represents an incoming connection.
type connection struct {
transport *handshakeTransport
sshConn
// The connection protocol.
*mux
}
func (c *connection) Close() error {
return c.sshConn.conn.Close()
}
// sshConn provides net.Conn metadata, but disallows direct reads and
// writes.
type sshConn struct {
conn net.Conn
user string
sessionID []byte
clientVersion []byte
serverVersion []byte
}
func dup(src []byte) []byte {
dst := make([]byte, len(src))
copy(dst, src)
return dst
}
func (c *sshConn) User() string {
return c.user
}
func (c *sshConn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *sshConn) Close() error {
return c.conn.Close()
}
func (c *sshConn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *sshConn) SessionID() []byte {
return dup(c.sessionID)
}
func (c *sshConn) ClientVersion() []byte {
return dup(c.clientVersion)
}
func (c *sshConn) ServerVersion() []byte {
return dup(c.serverVersion)
}

23
pkg/proto/ssh/doc.go
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@ -1,23 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package ssh implements an SSH client and server.
SSH is a transport security protocol, an authentication protocol and a
family of application protocols. The most typical application level
protocol is a remote shell and this is specifically implemented. However,
the multiplexed nature of SSH is exposed to users that wish to support
others.
References:
[PROTOCOL]: https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=HEAD
[PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
[SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
This package does not fall under the stability promise of the Go language itself,
so its API may be changed when pressing needs arise.
*/
package ssh // import "github.com/Neur0toxine/sshpoke/pkg/proto/ssh"

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pkg/proto/ssh/handshake.go
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@ -1,758 +0,0 @@
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto/rand"
"errors"
"fmt"
"io"
"log"
"net"
"strings"
"sync"
)
// debugHandshake, if set, prints messages sent and received. Key
// exchange messages are printed as if DH were used, so the debug
// messages are wrong when using ECDH.
const debugHandshake = false
// chanSize sets the amount of buffering SSH connections. This is
// primarily for testing: setting chanSize=0 uncovers deadlocks more
// quickly.
const chanSize = 16
// keyingTransport is a packet based transport that supports key
// changes. It need not be thread-safe. It should pass through
// msgNewKeys in both directions.
type keyingTransport interface {
packetConn
// prepareKeyChange sets up a key change. The key change for a
// direction will be effected if a msgNewKeys message is sent
// or received.
prepareKeyChange(*algorithms, *kexResult) error
}
// handshakeTransport implements rekeying on top of a keyingTransport
// and offers a thread-safe writePacket() interface.
type handshakeTransport struct {
conn keyingTransport
config *Config
serverVersion []byte
clientVersion []byte
// hostKeys is non-empty if we are the server. In that case,
// it contains all host keys that can be used to sign the
// connection.
hostKeys []Signer
// publicKeyAuthAlgorithms is non-empty if we are the server. In that case,
// it contains the supported client public key authentication algorithms.
publicKeyAuthAlgorithms []string
// hostKeyAlgorithms is non-empty if we are the client. In that case,
// we accept these key types from the server as host key.
hostKeyAlgorithms []string
// On read error, incoming is closed, and readError is set.
incoming chan []byte
readError error
mu sync.Mutex
writeError error
sentInitPacket []byte
sentInitMsg *kexInitMsg
pendingPackets [][]byte // Used when a key exchange is in progress.
writePacketsLeft uint32
writeBytesLeft int64
// If the read loop wants to schedule a kex, it pings this
// channel, and the write loop will send out a kex
// message.
requestKex chan struct{}
// If the other side requests or confirms a kex, its kexInit
// packet is sent here for the write loop to find it.
startKex chan *pendingKex
kexLoopDone chan struct{} // closed (with writeError non-nil) when kexLoop exits
// data for host key checking
hostKeyCallback HostKeyCallback
dialAddress string
remoteAddr net.Addr
// bannerCallback is non-empty if we are the client and it has been set in
// ClientConfig. In that case it is called during the user authentication
// dance to handle a custom server's message.
bannerCallback BannerCallback
// Algorithms agreed in the last key exchange.
algorithms *algorithms
// Counters exclusively owned by readLoop.
readPacketsLeft uint32
readBytesLeft int64
// The session ID or nil if first kex did not complete yet.
sessionID []byte
}
type pendingKex struct {
otherInit []byte
done chan error
}
func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion, serverVersion []byte) *handshakeTransport {
t := &handshakeTransport{
conn: conn,
serverVersion: serverVersion,
clientVersion: clientVersion,
incoming: make(chan []byte, chanSize),
requestKex: make(chan struct{}, 1),
startKex: make(chan *pendingKex),
kexLoopDone: make(chan struct{}),
config: config,
}
t.resetReadThresholds()
t.resetWriteThresholds()
// We always start with a mandatory key exchange.
t.requestKex <- struct{}{}
return t
}
func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ClientConfig, dialAddr string, addr net.Addr) *handshakeTransport {
t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
t.dialAddress = dialAddr
t.remoteAddr = addr
t.hostKeyCallback = config.HostKeyCallback
t.bannerCallback = config.BannerCallback
if config.HostKeyAlgorithms != nil {
t.hostKeyAlgorithms = config.HostKeyAlgorithms
} else {
t.hostKeyAlgorithms = supportedHostKeyAlgos
}
go t.readLoop()
go t.kexLoop()
return t
}
func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ServerConfig) *handshakeTransport {
t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
t.hostKeys = config.hostKeys
t.publicKeyAuthAlgorithms = config.PublicKeyAuthAlgorithms
go t.readLoop()
go t.kexLoop()
return t
}
func (t *handshakeTransport) getSessionID() []byte {
return t.sessionID
}
// waitSession waits for the session to be established. This should be
// the first thing to call after instantiating handshakeTransport.
func (t *handshakeTransport) waitSession() error {
p, err := t.readPacket()
if err != nil {
return err
}
if p[0] != msgNewKeys {
return fmt.Errorf("ssh: first packet should be msgNewKeys")
}
return nil
}
func (t *handshakeTransport) id() string {
if len(t.hostKeys) > 0 {
return "server"
}
return "client"
}
func (t *handshakeTransport) printPacket(p []byte, write bool) {
action := "got"
if write {
action = "sent"
}
if p[0] == msgChannelData || p[0] == msgChannelExtendedData {
log.Printf("%s %s data (packet %d bytes)", t.id(), action, len(p))
} else {
msg, err := decode(p)
log.Printf("%s %s %T %v (%v)", t.id(), action, msg, msg, err)
}
}
func (t *handshakeTransport) readPacket() ([]byte, error) {
p, ok := <-t.incoming
if !ok {
return nil, t.readError
}
return p, nil
}
func (t *handshakeTransport) readLoop() {
first := true
for {
p, err := t.readOnePacket(first)
first = false
if err != nil {
t.readError = err
close(t.incoming)
break
}
if p[0] == msgIgnore || p[0] == msgDebug {
continue
}
t.incoming <- p
}
// Stop writers too.
t.recordWriteError(t.readError)
// Unblock the writer should it wait for this.
close(t.startKex)
// Don't close t.requestKex; it's also written to from writePacket.
}
func (t *handshakeTransport) pushPacket(p []byte) error {
if debugHandshake {
t.printPacket(p, true)
}
return t.conn.writePacket(p)
}
func (t *handshakeTransport) getWriteError() error {
t.mu.Lock()
defer t.mu.Unlock()
return t.writeError
}
func (t *handshakeTransport) recordWriteError(err error) {
t.mu.Lock()
defer t.mu.Unlock()
if t.writeError == nil && err != nil {
t.writeError = err
}
}
func (t *handshakeTransport) requestKeyExchange() {
select {
case t.requestKex <- struct{}{}:
default:
// something already requested a kex, so do nothing.
}
}
func (t *handshakeTransport) resetWriteThresholds() {
t.writePacketsLeft = packetRekeyThreshold
if t.config.RekeyThreshold > 0 {
t.writeBytesLeft = int64(t.config.RekeyThreshold)
} else if t.algorithms != nil {
t.writeBytesLeft = t.algorithms.w.rekeyBytes()
} else {
t.writeBytesLeft = 1 << 30
}
}
func (t *handshakeTransport) kexLoop() {
write:
for t.getWriteError() == nil {
var request *pendingKex
var sent bool
for request == nil || !sent {
var ok bool
select {
case request, ok = <-t.startKex:
if !ok {
break write
}
case <-t.requestKex:
break
}
if !sent {
if err := t.sendKexInit(); err != nil {
t.recordWriteError(err)
break
}
sent = true
}
}
if err := t.getWriteError(); err != nil {
if request != nil {
request.done <- err
}
break
}
// We're not servicing t.requestKex, but that is OK:
// we never block on sending to t.requestKex.
// We're not servicing t.startKex, but the remote end
// has just sent us a kexInitMsg, so it can't send
// another key change request, until we close the done
// channel on the pendingKex request.
err := t.enterKeyExchange(request.otherInit)
t.mu.Lock()
t.writeError = err
t.sentInitPacket = nil
t.sentInitMsg = nil
t.resetWriteThresholds()
// we have completed the key exchange. Since the
// reader is still blocked, it is safe to clear out
// the requestKex channel. This avoids the situation
// where: 1) we consumed our own request for the
// initial kex, and 2) the kex from the remote side
// caused another send on the requestKex channel,
clear:
for {
select {
case <-t.requestKex:
//
default:
break clear
}
}
request.done <- t.writeError
// kex finished. Push packets that we received while
// the kex was in progress. Don't look at t.startKex
// and don't increment writtenSinceKex: if we trigger
// another kex while we are still busy with the last
// one, things will become very confusing.
for _, p := range t.pendingPackets {
t.writeError = t.pushPacket(p)
if t.writeError != nil {
break
}
}
t.pendingPackets = t.pendingPackets[:0]
t.mu.Unlock()
}
// Unblock reader.
t.conn.Close()
// drain startKex channel. We don't service t.requestKex
// because nobody does blocking sends there.
for request := range t.startKex {
request.done <- t.getWriteError()
}
// Mark that the loop is done so that Close can return.
close(t.kexLoopDone)
}
// The protocol uses uint32 for packet counters, so we can't let them
// reach 1<<32. We will actually read and write more packets than
// this, though: the other side may send more packets, and after we
// hit this limit on writing we will send a few more packets for the
// key exchange itself.
const packetRekeyThreshold = (1 << 31)
func (t *handshakeTransport) resetReadThresholds() {
t.readPacketsLeft = packetRekeyThreshold
if t.config.RekeyThreshold > 0 {
t.readBytesLeft = int64(t.config.RekeyThreshold)
} else if t.algorithms != nil {
t.readBytesLeft = t.algorithms.r.rekeyBytes()
} else {
t.readBytesLeft = 1 << 30
}
}
func (t *handshakeTransport) readOnePacket(first bool) ([]byte, error) {
p, err := t.conn.readPacket()
if err != nil {
return nil, err
}
if t.readPacketsLeft > 0 {
t.readPacketsLeft--
} else {
t.requestKeyExchange()
}
if t.readBytesLeft > 0 {
t.readBytesLeft -= int64(len(p))
} else {
t.requestKeyExchange()
}
if debugHandshake {
t.printPacket(p, false)
}
if first && p[0] != msgKexInit {
return nil, fmt.Errorf("ssh: first packet should be msgKexInit")
}
if p[0] != msgKexInit {
return p, nil
}
firstKex := t.sessionID == nil
kex := pendingKex{
done: make(chan error, 1),
otherInit: p,
}
t.startKex <- &kex
err = <-kex.done
if debugHandshake {
log.Printf("%s exited key exchange (first %v), err %v", t.id(), firstKex, err)
}
if err != nil {
return nil, err
}
t.resetReadThresholds()
// By default, a key exchange is hidden from higher layers by
// translating it into msgIgnore.
successPacket := []byte{msgIgnore}
if firstKex {
// sendKexInit() for the first kex waits for
// msgNewKeys so the authentication process is
// guaranteed to happen over an encrypted transport.
successPacket = []byte{msgNewKeys}
}
return successPacket, nil
}
// sendKexInit sends a key change message.
func (t *handshakeTransport) sendKexInit() error {
t.mu.Lock()
defer t.mu.Unlock()
if t.sentInitMsg != nil {
// kexInits may be sent either in response to the other side,
// or because our side wants to initiate a key change, so we
// may have already sent a kexInit. In that case, don't send a
// second kexInit.
return nil
}
msg := &kexInitMsg{
KexAlgos: t.config.KeyExchanges,
CiphersClientServer: t.config.Ciphers,
CiphersServerClient: t.config.Ciphers,
MACsClientServer: t.config.MACs,
MACsServerClient: t.config.MACs,
CompressionClientServer: supportedCompressions,
CompressionServerClient: supportedCompressions,
}
io.ReadFull(rand.Reader, msg.Cookie[:])
isServer := len(t.hostKeys) > 0
if isServer {
for _, k := range t.hostKeys {
// If k is a MultiAlgorithmSigner, we restrict the signature
// algorithms. If k is a AlgorithmSigner, presume it supports all
// signature algorithms associated with the key format. If k is not
// an AlgorithmSigner, we can only assume it only supports the
// algorithms that matches the key format. (This means that Sign
// can't pick a different default).
keyFormat := k.PublicKey().Type()
switch s := k.(type) {
case MultiAlgorithmSigner:
for _, algo := range algorithmsForKeyFormat(keyFormat) {
if contains(s.Algorithms(), underlyingAlgo(algo)) {
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algo)
}
}
case AlgorithmSigner:
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algorithmsForKeyFormat(keyFormat)...)
default:
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, keyFormat)
}
}
} else {
msg.ServerHostKeyAlgos = t.hostKeyAlgorithms
// As a client we opt in to receiving SSH_MSG_EXT_INFO so we know what
// algorithms the server supports for public key authentication. See RFC
// 8308, Section 2.1.
if firstKeyExchange := t.sessionID == nil; firstKeyExchange {
msg.KexAlgos = make([]string, 0, len(t.config.KeyExchanges)+1)
msg.KexAlgos = append(msg.KexAlgos, t.config.KeyExchanges...)
msg.KexAlgos = append(msg.KexAlgos, "ext-info-c")
}
}
packet := Marshal(msg)
// writePacket destroys the contents, so save a copy.
packetCopy := make([]byte, len(packet))
copy(packetCopy, packet)
if err := t.pushPacket(packetCopy); err != nil {
return err
}
t.sentInitMsg = msg
t.sentInitPacket = packet
return nil
}
func (t *handshakeTransport) writePacket(p []byte) error {
switch p[0] {
case msgKexInit:
return errors.New("ssh: only handshakeTransport can send kexInit")
case msgNewKeys:
return errors.New("ssh: only handshakeTransport can send newKeys")
}
t.mu.Lock()
defer t.mu.Unlock()
if t.writeError != nil {
return t.writeError
}
if t.sentInitMsg != nil {
// Copy the packet so the writer can reuse the buffer.
cp := make([]byte, len(p))
copy(cp, p)
t.pendingPackets = append(t.pendingPackets, cp)
return nil
}
if t.writeBytesLeft > 0 {
t.writeBytesLeft -= int64(len(p))
} else {
t.requestKeyExchange()
}
if t.writePacketsLeft > 0 {
t.writePacketsLeft--
} else {
t.requestKeyExchange()
}
if err := t.pushPacket(p); err != nil {
t.writeError = err
}
return nil
}
func (t *handshakeTransport) Close() error {
// Close the connection. This should cause the readLoop goroutine to wake up
// and close t.startKex, which will shut down kexLoop if running.
err := t.conn.Close()
// Wait for the kexLoop goroutine to complete.
// At that point we know that the readLoop goroutine is complete too,
// because kexLoop itself waits for readLoop to close the startKex channel.
<-t.kexLoopDone
return err
}
func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
if debugHandshake {
log.Printf("%s entered key exchange", t.id())
}
otherInit := &kexInitMsg{}
if err := Unmarshal(otherInitPacket, otherInit); err != nil {
return err
}
magics := handshakeMagics{
clientVersion: t.clientVersion,
serverVersion: t.serverVersion,
clientKexInit: otherInitPacket,
serverKexInit: t.sentInitPacket,
}
clientInit := otherInit
serverInit := t.sentInitMsg
isClient := len(t.hostKeys) == 0
if isClient {
clientInit, serverInit = serverInit, clientInit
magics.clientKexInit = t.sentInitPacket
magics.serverKexInit = otherInitPacket
}
var err error
t.algorithms, err = findAgreedAlgorithms(isClient, clientInit, serverInit)
if err != nil {
return err
}
// We don't send FirstKexFollows, but we handle receiving it.
//
// RFC 4253 section 7 defines the kex and the agreement method for
// first_kex_packet_follows. It states that the guessed packet
// should be ignored if the "kex algorithm and/or the host
// key algorithm is guessed wrong (server and client have
// different preferred algorithm), or if any of the other
// algorithms cannot be agreed upon". The other algorithms have
// already been checked above so the kex algorithm and host key
// algorithm are checked here.
if otherInit.FirstKexFollows && (clientInit.KexAlgos[0] != serverInit.KexAlgos[0] || clientInit.ServerHostKeyAlgos[0] != serverInit.ServerHostKeyAlgos[0]) {
// other side sent a kex message for the wrong algorithm,
// which we have to ignore.
if _, err := t.conn.readPacket(); err != nil {
return err
}
}
kex, ok := kexAlgoMap[t.algorithms.kex]
if !ok {
return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex)
}
var result *kexResult
if len(t.hostKeys) > 0 {
result, err = t.server(kex, &magics)
} else {
result, err = t.client(kex, &magics)
}
if err != nil {
return err
}
firstKeyExchange := t.sessionID == nil
if firstKeyExchange {
t.sessionID = result.H
}
result.SessionID = t.sessionID
if err := t.conn.prepareKeyChange(t.algorithms, result); err != nil {
return err
}
if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil {
return err
}
// On the server side, after the first SSH_MSG_NEWKEYS, send a SSH_MSG_EXT_INFO
// message with the server-sig-algs extension if the client supports it. See
// RFC 8308, Sections 2.4 and 3.1, and [PROTOCOL], Section 1.9.
if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") {
supportedPubKeyAuthAlgosList := strings.Join(t.publicKeyAuthAlgorithms, ",")
extInfo := &extInfoMsg{
NumExtensions: 2,
Payload: make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)+4+16+4+1),
}
extInfo.Payload = appendInt(extInfo.Payload, len("server-sig-algs"))
extInfo.Payload = append(extInfo.Payload, "server-sig-algs"...)
extInfo.Payload = appendInt(extInfo.Payload, len(supportedPubKeyAuthAlgosList))
extInfo.Payload = append(extInfo.Payload, supportedPubKeyAuthAlgosList...)
extInfo.Payload = appendInt(extInfo.Payload, len("ping@openssh.com"))
extInfo.Payload = append(extInfo.Payload, "ping@openssh.com"...)
extInfo.Payload = appendInt(extInfo.Payload, 1)
extInfo.Payload = append(extInfo.Payload, "0"...)
if err := t.conn.writePacket(Marshal(extInfo)); err != nil {
return err
}
}
if packet, err := t.conn.readPacket(); err != nil {
return err
} else if packet[0] != msgNewKeys {
return unexpectedMessageError(msgNewKeys, packet[0])
}
return nil
}
// algorithmSignerWrapper is an AlgorithmSigner that only supports the default
// key format algorithm.
//
// This is technically a violation of the AlgorithmSigner interface, but it
// should be unreachable given where we use this. Anyway, at least it returns an
// error instead of panicing or producing an incorrect signature.
type algorithmSignerWrapper struct {
Signer
}
func (a algorithmSignerWrapper) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) {
if algorithm != underlyingAlgo(a.PublicKey().Type()) {
return nil, errors.New("ssh: internal error: algorithmSignerWrapper invoked with non-default algorithm")
}
return a.Sign(rand, data)
}
func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
for _, k := range hostKeys {
if s, ok := k.(MultiAlgorithmSigner); ok {
if !contains(s.Algorithms(), underlyingAlgo(algo)) {
continue
}
}
if algo == k.PublicKey().Type() {
return algorithmSignerWrapper{k}
}
k, ok := k.(AlgorithmSigner)
if !ok {
continue
}
for _, a := range algorithmsForKeyFormat(k.PublicKey().Type()) {
if algo == a {
return k
}
}
}
return nil
}
func (t *handshakeTransport) server(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
hostKey := pickHostKey(t.hostKeys, t.algorithms.hostKey)
if hostKey == nil {
return nil, errors.New("ssh: internal error: negotiated unsupported signature type")
}
r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.hostKey)
return r, err
}
func (t *handshakeTransport) client(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
result, err := kex.Client(t.conn, t.config.Rand, magics)
if err != nil {
return nil, err
}
hostKey, err := ParsePublicKey(result.HostKey)
if err != nil {
return nil, err
}
if err := verifyHostKeySignature(hostKey, t.algorithms.hostKey, result); err != nil {
return nil, err
}
err = t.hostKeyCallback(t.dialAddress, t.remoteAddr, hostKey)
if err != nil {
return nil, err
}
return result, nil
}

93
pkg/proto/ssh/internal/bcrypt_pbkdf/bcrypt_pbkdf.go
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@ -1,93 +0,0 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package bcrypt_pbkdf implements bcrypt_pbkdf(3) from OpenBSD.
//
// See https://flak.tedunangst.com/post/bcrypt-pbkdf and
// https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libutil/bcrypt_pbkdf.c.
package bcrypt_pbkdf
import (
"crypto/sha512"
"errors"
"golang.org/x/crypto/blowfish"
)
const blockSize = 32
// Key derives a key from the password, salt and rounds count, returning a
// []byte of length keyLen that can be used as cryptographic key.
func Key(password, salt []byte, rounds, keyLen int) ([]byte, error) {
if rounds < 1 {
return nil, errors.New("bcrypt_pbkdf: number of rounds is too small")
}
if len(password) == 0 {
return nil, errors.New("bcrypt_pbkdf: empty password")
}
if len(salt) == 0 || len(salt) > 1<<20 {
return nil, errors.New("bcrypt_pbkdf: bad salt length")
}
if keyLen > 1024 {
return nil, errors.New("bcrypt_pbkdf: keyLen is too large")
}
numBlocks := (keyLen + blockSize - 1) / blockSize
key := make([]byte, numBlocks*blockSize)
h := sha512.New()
h.Write(password)
shapass := h.Sum(nil)
shasalt := make([]byte, 0, sha512.Size)
cnt, tmp := make([]byte, 4), make([]byte, blockSize)
for block := 1; block <= numBlocks; block++ {
h.Reset()
h.Write(salt)
cnt[0] = byte(block >> 24)
cnt[1] = byte(block >> 16)
cnt[2] = byte(block >> 8)
cnt[3] = byte(block)
h.Write(cnt)
bcryptHash(tmp, shapass, h.Sum(shasalt))
out := make([]byte, blockSize)
copy(out, tmp)
for i := 2; i <= rounds; i++ {
h.Reset()
h.Write(tmp)
bcryptHash(tmp, shapass, h.Sum(shasalt))
for j := 0; j < len(out); j++ {
out[j] ^= tmp[j]
}
}
for i, v := range out {
key[i*numBlocks+(block-1)] = v
}
}
return key[:keyLen], nil
}
var magic = []byte("OxychromaticBlowfishSwatDynamite")
func bcryptHash(out, shapass, shasalt []byte) {
c, err := blowfish.NewSaltedCipher(shapass, shasalt)
if err != nil {
panic(err)
}
for i := 0; i < 64; i++ {
blowfish.ExpandKey(shasalt, c)
blowfish.ExpandKey(shapass, c)
}
copy(out, magic)
for i := 0; i < 32; i += 8 {
for j := 0; j < 64; j++ {
c.Encrypt(out[i:i+8], out[i:i+8])
}
}
// Swap bytes due to different endianness.
for i := 0; i < 32; i += 4 {
out[i+3], out[i+2], out[i+1], out[i] = out[i], out[i+1], out[i+2], out[i+3]
}
}

39
pkg/proto/ssh/internal/poly1305/bits_compat.go
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@ -1,39 +0,0 @@
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build !go1.13
package poly1305
// Generic fallbacks for the math/bits intrinsics, copied from
// src/math/bits/bits.go. They were added in Go 1.12, but Add64 and Sum64 had
// variable time fallbacks until Go 1.13.
func bitsAdd64(x, y, carry uint64) (sum, carryOut uint64) {
sum = x + y + carry
carryOut = ((x & y) | ((x | y) &^ sum)) >> 63
return
}
func bitsSub64(x, y, borrow uint64) (diff, borrowOut uint64) {
diff = x - y - borrow
borrowOut = ((^x & y) | (^(x ^ y) & diff)) >> 63
return
}
func bitsMul64(x, y uint64) (hi, lo uint64) {
const mask32 = 1<<32 - 1
x0 := x & mask32
x1 := x >> 32
y0 := y & mask32
y1 := y >> 32
w0 := x0 * y0
t := x1*y0 + w0>>32
w1 := t & mask32
w2 := t >> 32
w1 += x0 * y1
hi = x1*y1 + w2 + w1>>32
lo = x * y
return
}

21
pkg/proto/ssh/internal/poly1305/bits_go1.13.go
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@ -1,21 +0,0 @@
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build go1.13
package poly1305
import "math/bits"
func bitsAdd64(x, y, carry uint64) (sum, carryOut uint64) {
return bits.Add64(x, y, carry)
}
func bitsSub64(x, y, borrow uint64) (diff, borrowOut uint64) {
return bits.Sub64(x, y, borrow)
}
func bitsMul64(x, y uint64) (hi, lo uint64) {
return bits.Mul64(x, y)
}

9
pkg/proto/ssh/internal/poly1305/mac_noasm.go
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@ -1,9 +0,0 @@
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build (!amd64 && !ppc64le && !s390x) || !gc || purego
package poly1305
type mac struct{ macGeneric }

99
pkg/proto/ssh/internal/poly1305/poly1305.go
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@ -1,99 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package poly1305 implements Poly1305 one-time message authentication code as
// specified in https://cr.yp.to/mac/poly1305-20050329.pdf.
//
// Poly1305 is a fast, one-time authentication function. It is infeasible for an
// attacker to generate an authenticator for a message without the key. However, a
// key must only be used for a single message. Authenticating two different
// messages with the same key allows an attacker to forge authenticators for other
// messages with the same key.
//
// Poly1305 was originally coupled with AES in order to make Poly1305-AES. AES was
// used with a fixed key in order to generate one-time keys from an nonce.
// However, in this package AES isn't used and the one-time key is specified
// directly.
package poly1305
import "crypto/subtle"
// TagSize is the size, in bytes, of a poly1305 authenticator.
const TagSize = 16
// Sum generates an authenticator for msg using a one-time key and puts the
// 16-byte result into out. Authenticating two different messages with the same
// key allows an attacker to forge messages at will.
func Sum(out *[16]byte, m []byte, key *[32]byte) {
h := New(key)
h.Write(m)
h.Sum(out[:0])
}
// Verify returns true if mac is a valid authenticator for m with the given key.
func Verify(mac *[16]byte, m []byte, key *[32]byte) bool {
var tmp [16]byte
Sum(&tmp, m, key)
return subtle.ConstantTimeCompare(tmp[:], mac[:]) == 1
}
// New returns a new MAC computing an authentication
// tag of all data written to it with the given key.
// This allows writing the message progressively instead
// of passing it as a single slice. Common users should use
// the Sum function instead.
//
// The key must be unique for each message, as authenticating
// two different messages with the same key allows an attacker
// to forge messages at will.
func New(key *[32]byte) *MAC {
m := &MAC{}
initialize(key, &m.macState)
return m
}
// MAC is an io.Writer computing an authentication tag
// of the data written to it.
//
// MAC cannot be used like common hash.Hash implementations,
// because using a poly1305 key twice breaks its security.
// Therefore writing data to a running MAC after calling
// Sum or Verify causes it to panic.
type MAC struct {
mac // platform-dependent implementation
finalized bool
}
// Size returns the number of bytes Sum will return.
func (h *MAC) Size() int { return TagSize }
// Write adds more data to the running message authentication code.
// It never returns an error.
//
// It must not be called after the first call of Sum or Verify.
func (h *MAC) Write(p []byte) (n int, err error) {
if h.finalized {
panic("poly1305: write to MAC after Sum or Verify")
}
return h.mac.Write(p)
}
// Sum computes the authenticator of all data written to the
// message authentication code.
func (h *MAC) Sum(b []byte) []byte {
var mac [TagSize]byte
h.mac.Sum(&mac)
h.finalized = true
return append(b, mac[:]...)
}
// Verify returns whether the authenticator of all data written to
// the message authentication code matches the expected value.
func (h *MAC) Verify(expected []byte) bool {
var mac [TagSize]byte
h.mac.Sum(&mac)
h.finalized = true
return subtle.ConstantTimeCompare(expected, mac[:]) == 1
}

47
pkg/proto/ssh/internal/poly1305/sum_amd64.go
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@ -1,47 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
package poly1305
//go:noescape
func update(state *macState, msg []byte)
// mac is a wrapper for macGeneric that redirects calls that would have gone to
// updateGeneric to update.
//
// Its Write and Sum methods are otherwise identical to the macGeneric ones, but
// using function pointers would carry a major performance cost.
type mac struct{ macGeneric }
func (h *mac) Write(p []byte) (int, error) {
nn := len(p)
if h.offset > 0 {
n := copy(h.buffer[h.offset:], p)
if h.offset+n < TagSize {
h.offset += n
return nn, nil
}
p = p[n:]
h.offset = 0
update(&h.macState, h.buffer[:])
}
if n := len(p) - (len(p) % TagSize); n > 0 {
update(&h.macState, p[:n])
p = p[n:]
}
if len(p) > 0 {
h.offset += copy(h.buffer[h.offset:], p)
}
return nn, nil
}
func (h *mac) Sum(out *[16]byte) {
state := h.macState
if h.offset > 0 {
update(&state, h.buffer[:h.offset])
}
finalize(out, &state.h, &state.s)
}

108
pkg/proto/ssh/internal/poly1305/sum_amd64.s
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@ -1,108 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
#include "textflag.h"
#define POLY1305_ADD(msg, h0, h1, h2) \
ADDQ 0(msg), h0; \
ADCQ 8(msg), h1; \
ADCQ $1, h2; \
LEAQ 16(msg), msg
#define POLY1305_MUL(h0, h1, h2, r0, r1, t0, t1, t2, t3) \
MOVQ r0, AX; \
MULQ h0; \
MOVQ AX, t0; \
MOVQ DX, t1; \
MOVQ r0, AX; \
MULQ h1; \
ADDQ AX, t1; \
ADCQ $0, DX; \
MOVQ r0, t2; \
IMULQ h2, t2; \
ADDQ DX, t2; \
\
MOVQ r1, AX; \
MULQ h0; \
ADDQ AX, t1; \
ADCQ $0, DX; \
MOVQ DX, h0; \
MOVQ r1, t3; \
IMULQ h2, t3; \
MOVQ r1, AX; \
MULQ h1; \
ADDQ AX, t2; \
ADCQ DX, t3; \
ADDQ h0, t2; \
ADCQ $0, t3; \
\
MOVQ t0, h0; \
MOVQ t1, h1; \
MOVQ t2, h2; \
ANDQ $3, h2; \
MOVQ t2, t0; \
ANDQ $0xFFFFFFFFFFFFFFFC, t0; \
ADDQ t0, h0; \
ADCQ t3, h1; \
ADCQ $0, h2; \
SHRQ $2, t3, t2; \
SHRQ $2, t3; \
ADDQ t2, h0; \
ADCQ t3, h1; \
ADCQ $0, h2
// func update(state *[7]uint64, msg []byte)
TEXT ·update(SB), $0-32
MOVQ state+0(FP), DI
MOVQ msg_base+8(FP), SI
MOVQ msg_len+16(FP), R15
MOVQ 0(DI), R8 // h0
MOVQ 8(DI), R9 // h1
MOVQ 16(DI), R10 // h2
MOVQ 24(DI), R11 // r0
MOVQ 32(DI), R12 // r1
CMPQ R15, $16
JB bytes_between_0_and_15
loop:
POLY1305_ADD(SI, R8, R9, R10)
multiply:
POLY1305_MUL(R8, R9, R10, R11, R12, BX, CX, R13, R14)
SUBQ $16, R15
CMPQ R15, $16
JAE loop
bytes_between_0_and_15:
TESTQ R15, R15
JZ done
MOVQ $1, BX
XORQ CX, CX
XORQ R13, R13
ADDQ R15, SI
flush_buffer:
SHLQ $8, BX, CX
SHLQ $8, BX
MOVB -1(SI), R13
XORQ R13, BX
DECQ SI
DECQ R15
JNZ flush_buffer
ADDQ BX, R8
ADCQ CX, R9
ADCQ $0, R10
MOVQ $16, R15
JMP multiply
done:
MOVQ R8, 0(DI)
MOVQ R9, 8(DI)
MOVQ R10, 16(DI)
RET

309
pkg/proto/ssh/internal/poly1305/sum_generic.go
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@ -1,309 +0,0 @@
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file provides the generic implementation of Sum and MAC. Other files
// might provide optimized assembly implementations of some of this code.
package poly1305
import "encoding/binary"
// Poly1305 [RFC 7539] is a relatively simple algorithm: the authentication tag
// for a 64 bytes message is approximately
//
// s + m[0:16] * r⁴ + m[16:32] * r³ + m[32:48] * r² + m[48:64] * r mod 2¹³⁰ - 5
//
// for some secret r and s. It can be computed sequentially like
//
// for len(msg) > 0:
// h += read(msg, 16)
// h *= r
// h %= 2¹³⁰ - 5
// return h + s
//
// All the complexity is about doing performant constant-time math on numbers
// larger than any available numeric type.
func sumGeneric(out *[TagSize]byte, msg []byte, key *[32]byte) {
h := newMACGeneric(key)
h.Write(msg)
h.Sum(out)
}
func newMACGeneric(key *[32]byte) macGeneric {
m := macGeneric{}
initialize(key, &m.macState)
return m
}
// macState holds numbers in saturated 64-bit little-endian limbs. That is,
// the value of [x0, x1, x2] is x[0] + x[1] * 2⁶⁴ + x[2] * 2¹²⁸.
type macState struct {
// h is the main accumulator. It is to be interpreted modulo 2¹³⁰ - 5, but
// can grow larger during and after rounds. It must, however, remain below
// 2 * (2¹³⁰ - 5).
h [3]uint64
// r and s are the private key components.
r [2]uint64
s [2]uint64
}
type macGeneric struct {
macState
buffer [TagSize]byte
offset int
}
// Write splits the incoming message into TagSize chunks, and passes them to
// update. It buffers incomplete chunks.
func (h *macGeneric) Write(p []byte) (int, error) {
nn := len(p)
if h.offset > 0 {
n := copy(h.buffer[h.offset:], p)
if h.offset+n < TagSize {
h.offset += n
return nn, nil
}
p = p[n:]
h.offset = 0
updateGeneric(&h.macState, h.buffer[:])
}
if n := len(p) - (len(p) % TagSize); n > 0 {
updateGeneric(&h.macState, p[:n])
p = p[n:]
}
if len(p) > 0 {
h.offset += copy(h.buffer[h.offset:], p)
}
return nn, nil
}
// Sum flushes the last incomplete chunk from the buffer, if any, and generates
// the MAC output. It does not modify its state, in order to allow for multiple
// calls to Sum, even if no Write is allowed after Sum.
func (h *macGeneric) Sum(out *[TagSize]byte) {
state := h.macState
if h.offset > 0 {
updateGeneric(&state, h.buffer[:h.offset])
}
finalize(out, &state.h, &state.s)
}
// [rMask0, rMask1] is the specified Poly1305 clamping mask in little-endian. It
// clears some bits of the secret coefficient to make it possible to implement
// multiplication more efficiently.
const (
rMask0 = 0x0FFFFFFC0FFFFFFF
rMask1 = 0x0FFFFFFC0FFFFFFC
)
// initialize loads the 256-bit key into the two 128-bit secret values r and s.
func initialize(key *[32]byte, m *macState) {
m.r[0] = binary.LittleEndian.Uint64(key[0:8]) & rMask0
m.r[1] = binary.LittleEndian.Uint64(key[8:16]) & rMask1
m.s[0] = binary.LittleEndian.Uint64(key[16:24])
m.s[1] = binary.LittleEndian.Uint64(key[24:32])
}
// uint128 holds a 128-bit number as two 64-bit limbs, for use with the
// bits.Mul64 and bits.Add64 intrinsics.
type uint128 struct {
lo, hi uint64
}
func mul64(a, b uint64) uint128 {
hi, lo := bitsMul64(a, b)
return uint128{lo, hi}
}
func add128(a, b uint128) uint128 {
lo, c := bitsAdd64(a.lo, b.lo, 0)
hi, c := bitsAdd64(a.hi, b.hi, c)
if c != 0 {
panic("poly1305: unexpected overflow")
}
return uint128{lo, hi}
}
func shiftRightBy2(a uint128) uint128 {
a.lo = a.lo>>2 | (a.hi&3)<<62
a.hi = a.hi >> 2
return a
}
// updateGeneric absorbs msg into the state.h accumulator. For each chunk m of
// 128 bits of message, it computes
//
// h₊ = (h + m) * r mod 2¹³⁰ - 5
//
// If the msg length is not a multiple of TagSize, it assumes the last
// incomplete chunk is the final one.
func updateGeneric(state *macState, msg []byte) {
h0, h1, h2 := state.h[0], state.h[1], state.h[2]
r0, r1 := state.r[0], state.r[1]
for len(msg) > 0 {
var c uint64
// For the first step, h + m, we use a chain of bits.Add64 intrinsics.
// The resulting value of h might exceed 2¹³⁰ - 5, but will be partially
// reduced at the end of the multiplication below.
//
// The spec requires us to set a bit just above the message size, not to
// hide leading zeroes. For full chunks, that's 1 << 128, so we can just
// add 1 to the most significant (2¹²⁸) limb, h2.
if len(msg) >= TagSize {
h0, c = bitsAdd64(h0, binary.LittleEndian.Uint64(msg[0:8]), 0)
h1, c = bitsAdd64(h1, binary.LittleEndian.Uint64(msg[8:16]), c)
h2 += c + 1
msg = msg[TagSize:]
} else {
var buf [TagSize]byte
copy(buf[:], msg)
buf[len(msg)] = 1
h0, c = bitsAdd64(h0, binary.LittleEndian.Uint64(buf[0:8]), 0)
h1, c = bitsAdd64(h1, binary.LittleEndian.Uint64(buf[8:16]), c)
h2 += c
msg = nil
}
// Multiplication of big number limbs is similar to elementary school
// columnar multiplication. Instead of digits, there are 64-bit limbs.
//
// We are multiplying a 3 limbs number, h, by a 2 limbs number, r.
//
// h2 h1 h0 x
// r1 r0 =
// ----------------
// h2r0 h1r0 h0r0 <-- individual 128-bit products
// + h2r1 h1r1 h0r1
// ------------------------
// m3 m2 m1 m0 <-- result in 128-bit overlapping limbs
// ------------------------
// m3.hi m2.hi m1.hi m0.hi <-- carry propagation
// + m3.lo m2.lo m1.lo m0.lo
// -------------------------------
// t4 t3 t2 t1 t0 <-- final result in 64-bit limbs
//
// The main difference from pen-and-paper multiplication is that we do
// carry propagation in a separate step, as if we wrote two digit sums
// at first (the 128-bit limbs), and then carried the tens all at once.
h0r0 := mul64(h0, r0)
h1r0 := mul64(h1, r0)
h2r0 := mul64(h2, r0)
h0r1 := mul64(h0, r1)
h1r1 := mul64(h1, r1)
h2r1 := mul64(h2, r1)
// Since h2 is known to be at most 7 (5 + 1 + 1), and r0 and r1 have their
// top 4 bits cleared by rMask{0,1}, we know that their product is not going
// to overflow 64 bits, so we can ignore the high part of the products.
//
// This also means that the product doesn't have a fifth limb (t4).
if h2r0.hi != 0 {
panic("poly1305: unexpected overflow")
}
if h2r1.hi != 0 {
panic("poly1305: unexpected overflow")
}
m0 := h0r0
m1 := add128(h1r0, h0r1) // These two additions don't overflow thanks again
m2 := add128(h2r0, h1r1) // to the 4 masked bits at the top of r0 and r1.
m3 := h2r1
t0 := m0.lo
t1, c := bitsAdd64(m1.lo, m0.hi, 0)
t2, c := bitsAdd64(m2.lo, m1.hi, c)
t3, _ := bitsAdd64(m3.lo, m2.hi, c)
// Now we have the result as 4 64-bit limbs, and we need to reduce it
// modulo 2¹³⁰ - 5. The special shape of this Crandall prime lets us do
// a cheap partial reduction according to the reduction identity
//
// c * 2¹³⁰ + n = c * 5 + n mod 2¹³⁰ - 5
//
// because 2¹³⁰ = 5 mod 2¹³⁰ - 5. Partial reduction since the result is
// likely to be larger than 2¹³⁰ - 5, but still small enough to fit the
// assumptions we make about h in the rest of the code.
//
// See also https://speakerdeck.com/gtank/engineering-prime-numbers?slide=23
// We split the final result at the 2¹³⁰ mark into h and cc, the carry.
// Note that the carry bits are effectively shifted left by 2, in other
// words, cc = c * 4 for the c in the reduction identity.
h0, h1, h2 = t0, t1, t2&maskLow2Bits
cc := uint128{t2 & maskNotLow2Bits, t3}
// To add c * 5 to h, we first add cc = c * 4, and then add (cc >> 2) = c.
h0, c = bitsAdd64(h0, cc.lo, 0)
h1, c = bitsAdd64(h1, cc.hi, c)
h2 += c
cc = shiftRightBy2(cc)
h0, c = bitsAdd64(h0, cc.lo, 0)
h1, c = bitsAdd64(h1, cc.hi, c)
h2 += c
// h2 is at most 3 + 1 + 1 = 5, making the whole of h at most
//
// 5 * 2¹²⁸ + (2¹²⁸ - 1) = 6 * 2¹²⁸ - 1
}
state.h[0], state.h[1], state.h[2] = h0, h1, h2
}
const (
maskLow2Bits uint64 = 0x0000000000000003
maskNotLow2Bits uint64 = ^maskLow2Bits
)
// select64 returns x if v == 1 and y if v == 0, in constant time.
func select64(v, x, y uint64) uint64 { return ^(v-1)&x | (v-1)&y }
// [p0, p1, p2] is 2¹³⁰ - 5 in little endian order.
const (
p0 = 0xFFFFFFFFFFFFFFFB
p1 = 0xFFFFFFFFFFFFFFFF
p2 = 0x0000000000000003
)
// finalize completes the modular reduction of h and computes
//
// out = h + s mod 2¹²⁸
func finalize(out *[TagSize]byte, h *[3]uint64, s *[2]uint64) {
h0, h1, h2 := h[0], h[1], h[2]
// After the partial reduction in updateGeneric, h might be more than
// 2¹³⁰ - 5, but will be less than 2 * (2¹³⁰ - 5). To complete the reduction
// in constant time, we compute t = h - (2¹³⁰ - 5), and select h as the
// result if the subtraction underflows, and t otherwise.
hMinusP0, b := bitsSub64(h0, p0, 0)
hMinusP1, b := bitsSub64(h1, p1, b)
_, b = bitsSub64(h2, p2, b)
// h = h if h < p else h - p
h0 = select64(b, h0, hMinusP0)
h1 = select64(b, h1, hMinusP1)
// Finally, we compute the last Poly1305 step
//
// tag = h + s mod 2¹²⁸
//
// by just doing a wide addition with the 128 low bits of h and discarding
// the overflow.
h0, c := bitsAdd64(h0, s[0], 0)
h1, _ = bitsAdd64(h1, s[1], c)
binary.LittleEndian.PutUint64(out[0:8], h0)
binary.LittleEndian.PutUint64(out[8:16], h1)
}

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pkg/proto/ssh/internal/poly1305/sum_ppc64le.go
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@ -1,47 +0,0 @@
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
package poly1305
//go:noescape
func update(state *macState, msg []byte)
// mac is a wrapper for macGeneric that redirects calls that would have gone to
// updateGeneric to update.
//
// Its Write and Sum methods are otherwise identical to the macGeneric ones, but
// using function pointers would carry a major performance cost.
type mac struct{ macGeneric }
func (h *mac) Write(p []byte) (int, error) {
nn := len(p)
if h.offset > 0 {
n := copy(h.buffer[h.offset:], p)
if h.offset+n < TagSize {
h.offset += n
return nn, nil
}
p = p[n:]
h.offset = 0
update(&h.macState, h.buffer[:])
}
if n := len(p) - (len(p) % TagSize); n > 0 {
update(&h.macState, p[:n])
p = p[n:]
}
if len(p) > 0 {
h.offset += copy(h.buffer[h.offset:], p)
}
return nn, nil
}
func (h *mac) Sum(out *[16]byte) {
state := h.macState
if h.offset > 0 {
update(&state, h.buffer[:h.offset])
}
finalize(out, &state.h, &state.s)
}

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pkg/proto/ssh/internal/poly1305/sum_ppc64le.s
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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
#include "textflag.h"
// This was ported from the amd64 implementation.
#define POLY1305_ADD(msg, h0, h1, h2, t0, t1, t2) \
MOVD (msg), t0; \
MOVD 8(msg), t1; \
MOVD $1, t2; \
ADDC t0, h0, h0; \
ADDE t1, h1, h1; \
ADDE t2, h2; \
ADD $16, msg
#define POLY1305_MUL(h0, h1, h2, r0, r1, t0, t1, t2, t3, t4, t5) \
MULLD r0, h0, t0; \
MULLD r0, h1, t4; \
MULHDU r0, h0, t1; \
MULHDU r0, h1, t5; \
ADDC t4, t1, t1; \
MULLD r0, h2, t2; \
ADDZE t5; \
MULHDU r1, h0, t4; \
MULLD r1, h0, h0; \
ADD t5, t2, t2; \
ADDC h0, t1, t1; \
MULLD h2, r1, t3; \
ADDZE t4, h0; \
MULHDU r1, h1, t5; \
MULLD r1, h1, t4; \
ADDC t4, t2, t2; \
ADDE t5, t3, t3; \
ADDC h0, t2, t2; \
MOVD $-4, t4; \
MOVD t0, h0; \
MOVD t1, h1; \
ADDZE t3; \
ANDCC $3, t2, h2; \
AND t2, t4, t0; \
ADDC t0, h0, h0; \
ADDE t3, h1, h1; \
SLD $62, t3, t4; \
SRD $2, t2; \
ADDZE h2; \
OR t4, t2, t2; \
SRD $2, t3; \
ADDC t2, h0, h0; \
ADDE t3, h1, h1; \
ADDZE h2
DATA ·poly1305Mask<>+0x00(SB)/8, $0x0FFFFFFC0FFFFFFF
DATA ·poly1305Mask<>+0x08(SB)/8, $0x0FFFFFFC0FFFFFFC
GLOBL ·poly1305Mask<>(SB), RODATA, $16
// func update(state *[7]uint64, msg []byte)
TEXT ·update(SB), $0-32
MOVD state+0(FP), R3
MOVD msg_base+8(FP), R4
MOVD msg_len+16(FP), R5
MOVD 0(R3), R8 // h0
MOVD 8(R3), R9 // h1
MOVD 16(R3), R10 // h2
MOVD 24(R3), R11 // r0
MOVD 32(R3), R12 // r1
CMP R5, $16
BLT bytes_between_0_and_15
loop:
POLY1305_ADD(R4, R8, R9, R10, R20, R21, R22)
multiply:
POLY1305_MUL(R8, R9, R10, R11, R12, R16, R17, R18, R14, R20, R21)
ADD $-16, R5
CMP R5, $16
BGE loop
bytes_between_0_and_15:
CMP R5, $0
BEQ done
MOVD $0, R16 // h0
MOVD $0, R17 // h1
flush_buffer:
CMP R5, $8
BLE just1
MOVD $8, R21
SUB R21, R5, R21
// Greater than 8 -- load the rightmost remaining bytes in msg
// and put into R17 (h1)
MOVD (R4)(R21), R17
MOVD $16, R22
// Find the offset to those bytes
SUB R5, R22, R22
SLD $3, R22
// Shift to get only the bytes in msg
SRD R22, R17, R17
// Put 1 at high end
MOVD $1, R23
SLD $3, R21
SLD R21, R23, R23
OR R23, R17, R17
// Remainder is 8
MOVD $8, R5
just1:
CMP R5, $8
BLT less8
// Exactly 8
MOVD (R4), R16
CMP R17, $0
// Check if we've already set R17; if not
// set 1 to indicate end of msg.
BNE carry
MOVD $1, R17
BR carry
less8:
MOVD $0, R16 // h0
MOVD $0, R22 // shift count
CMP R5, $4
BLT less4
MOVWZ (R4), R16
ADD $4, R4
ADD $-4, R5
MOVD $32, R22
less4:
CMP R5, $2
BLT less2
MOVHZ (R4), R21
SLD R22, R21, R21
OR R16, R21, R16
ADD $16, R22
ADD $-2, R5
ADD $2, R4
less2:
CMP R5, $0
BEQ insert1
MOVBZ (R4), R21
SLD R22, R21, R21
OR R16, R21, R16
ADD $8, R22
insert1:
// Insert 1 at end of msg
MOVD $1, R21
SLD R22, R21, R21
OR R16, R21, R16
carry:
// Add new values to h0, h1, h2
ADDC R16, R8
ADDE R17, R9
ADDZE R10, R10
MOVD $16, R5
ADD R5, R4
BR multiply
done:
// Save h0, h1, h2 in state
MOVD R8, 0(R3)
MOVD R9, 8(R3)
MOVD R10, 16(R3)
RET

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pkg/proto/ssh/internal/poly1305/sum_s390x.go
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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
package poly1305
import (
"golang.org/x/sys/cpu"
)
// updateVX is an assembly implementation of Poly1305 that uses vector
// instructions. It must only be called if the vector facility (vx) is
// available.
//
//go:noescape
func updateVX(state *macState, msg []byte)
// mac is a replacement for macGeneric that uses a larger buffer and redirects
// calls that would have gone to updateGeneric to updateVX if the vector
// facility is installed.
//
// A larger buffer is required for good performance because the vector
// implementation has a higher fixed cost per call than the generic
// implementation.
type mac struct {
macState
buffer [16 * TagSize]byte // size must be a multiple of block size (16)
offset int
}
func (h *mac) Write(p []byte) (int, error) {
nn := len(p)
if h.offset > 0 {
n := copy(h.buffer[h.offset:], p)
if h.offset+n < len(h.buffer) {
h.offset += n
return nn, nil
}
p = p[n:]
h.offset = 0
if cpu.S390X.HasVX {
updateVX(&h.macState, h.buffer[:])
} else {
updateGeneric(&h.macState, h.buffer[:])
}
}
tail := len(p) % len(h.buffer) // number of bytes to copy into buffer
body := len(p) - tail // number of bytes to process now
if body > 0 {
if cpu.S390X.HasVX {
updateVX(&h.macState, p[:body])
} else {
updateGeneric(&h.macState, p[:body])
}
}
h.offset = copy(h.buffer[:], p[body:]) // copy tail bytes - can be 0
return nn, nil
}
func (h *mac) Sum(out *[TagSize]byte) {
state := h.macState
remainder := h.buffer[:h.offset]
// Use the generic implementation if we have 2 or fewer blocks left
// to sum. The vector implementation has a higher startup time.
if cpu.S390X.HasVX && len(remainder) > 2*TagSize {
updateVX(&state, remainder)
} else if len(remainder) > 0 {
updateGeneric(&state, remainder)
}
finalize(out, &state.h, &state.s)
}

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pkg/proto/ssh/internal/poly1305/sum_s390x.s
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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build gc && !purego
#include "textflag.h"
// This implementation of Poly1305 uses the vector facility (vx)
// to process up to 2 blocks (32 bytes) per iteration using an
// algorithm based on the one described in:
//
// NEON crypto, Daniel J. Bernstein & Peter Schwabe
// https://cryptojedi.org/papers/neoncrypto-20120320.pdf
//
// This algorithm uses 5 26-bit limbs to represent a 130-bit
// value. These limbs are, for the most part, zero extended and
// placed into 64-bit vector register elements. Each vector
// register is 128-bits wide and so holds 2 of these elements.
// Using 26-bit limbs allows us plenty of headroom to accommodate
// accumulations before and after multiplication without
// overflowing either 32-bits (before multiplication) or 64-bits
// (after multiplication).
//
// In order to parallelise the operations required to calculate
// the sum we use two separate accumulators and then sum those
// in an extra final step. For compatibility with the generic
// implementation we perform this summation at the end of every
// updateVX call.
//
// To use two accumulators we must multiply the message blocks
// by r² rather than r. Only the final message block should be
// multiplied by r.
//
// Example:
//
// We want to calculate the sum (h) for a 64 byte message (m):
//
// h = m[0:16]r⁴ + m[16:32]r³ + m[32:48]r² + m[48:64]r
//
// To do this we split the calculation into the even indices
// and odd indices of the message. These form our SIMD 'lanes':
//
// h = m[ 0:16]r⁴ + m[32:48]r² + <- lane 0
// m[16:32]r³ + m[48:64]r <- lane 1
//
// To calculate this iteratively we refactor so that both lanes
// are written in terms of r² and r:
//
// h = (m[ 0:16]r² + m[32:48])r² + <- lane 0
// (m[16:32]r² + m[48:64])r <- lane 1
// ^ ^
// | coefficients for second iteration
// coefficients for first iteration
//
// So in this case we would have two iterations. In the first
// both lanes are multiplied by r². In the second only the
// first lane is multiplied by r² and the second lane is
// instead multiplied by r. This gives use the odd and even
// powers of r that we need from the original equation.
//
// Notation:
//
// h - accumulator
// r - key
// m - message
//
// [a, b] - SIMD register holding two 64-bit values
// [a, b, c, d] - SIMD register holding four 32-bit values
// xᵢ[n] - limb n of variable x with bit width i
//
// Limbs are expressed in little endian order, so for 26-bit
// limbs x₂₆[4] will be the most significant limb and x₂₆[0]
// will be the least significant limb.
// masking constants
#define MOD24 V0 // [0x0000000000ffffff, 0x0000000000ffffff] - mask low 24-bits
#define MOD26 V1 // [0x0000000003ffffff, 0x0000000003ffffff] - mask low 26-bits
// expansion constants (see EXPAND macro)
#define EX0 V2
#define EX1 V3
#define EX2 V4
// key (r², r or 1 depending on context)
#define R_0 V5
#define R_1 V6
#define R_2 V7
#define R_3 V8
#define R_4 V9
// precalculated coefficients (5r², 5r or 0 depending on context)
#define R5_1 V10
#define R5_2 V11
#define R5_3 V12
#define R5_4 V13
// message block (m)
#define M_0 V14
#define M_1 V15
#define M_2 V16
#define M_3 V17
#define M_4 V18
// accumulator (h)
#define H_0 V19
#define H_1 V20
#define H_2 V21
#define H_3 V22
#define H_4 V23
// temporary registers (for short-lived values)
#define T_0 V24
#define T_1 V25
#define T_2 V26
#define T_3 V27
#define T_4 V28
GLOBL ·constants<>(SB), RODATA, $0x30
// EX0
DATA ·constants<>+0x00(SB)/8, $0x0006050403020100
DATA ·constants<>+0x08(SB)/8, $0x1016151413121110
// EX1
DATA ·constants<>+0x10(SB)/8, $0x060c0b0a09080706
DATA ·constants<>+0x18(SB)/8, $0x161c1b1a19181716
// EX2
DATA ·constants<>+0x20(SB)/8, $0x0d0d0d0d0d0f0e0d
DATA ·constants<>+0x28(SB)/8, $0x1d1d1d1d1d1f1e1d
// MULTIPLY multiplies each lane of f and g, partially reduced
// modulo 2¹³⁰ - 5. The result, h, consists of partial products
// in each lane that need to be reduced further to produce the
// final result.
//
// h₁₃₀ = (f₁₃₀g₁₃₀) % 2¹³⁰ + (5f₁₃₀g₁₃₀) / 2¹³⁰
//
// Note that the multiplication by 5 of the high bits is
// achieved by precalculating the multiplication of four of the
// g coefficients by 5. These are g51-g54.
#define MULTIPLY(f0, f1, f2, f3, f4, g0, g1, g2, g3, g4, g51, g52, g53, g54, h0, h1, h2, h3, h4) \
VMLOF f0, g0, h0 \
VMLOF f0, g3, h3 \
VMLOF f0, g1, h1 \
VMLOF f0, g4, h4 \
VMLOF f0, g2, h2 \
VMLOF f1, g54, T_0 \
VMLOF f1, g2, T_3 \
VMLOF f1, g0, T_1 \
VMLOF f1, g3, T_4 \
VMLOF f1, g1, T_2 \
VMALOF f2, g53, h0, h0 \
VMALOF f2, g1, h3, h3 \
VMALOF f2, g54, h1, h1 \
VMALOF f2, g2, h4, h4 \
VMALOF f2, g0, h2, h2 \
VMALOF f3, g52, T_0, T_0 \
VMALOF f3, g0, T_3, T_3 \
VMALOF f3, g53, T_1, T_1 \
VMALOF f3, g1, T_4, T_4 \
VMALOF f3, g54, T_2, T_2 \
VMALOF f4, g51, h0, h0 \
VMALOF f4, g54, h3, h3 \
VMALOF f4, g52, h1, h1 \
VMALOF f4, g0, h4, h4 \
VMALOF f4, g53, h2, h2 \
VAG T_0, h0, h0 \
VAG T_3, h3, h3 \
VAG T_1, h1, h1 \
VAG T_4, h4, h4 \
VAG T_2, h2, h2
// REDUCE performs the following carry operations in four
// stages, as specified in Bernstein & Schwabe:
//
// 1: h₂₆[0]->h₂₆[1] h₂₆[3]->h₂₆[4]
// 2: h₂₆[1]->h₂₆[2] h₂₆[4]->h₂₆[0]
// 3: h₂₆[0]->h₂₆[1] h₂₆[2]->h₂₆[3]
// 4: h₂₆[3]->h₂₆[4]
//
// The result is that all of the limbs are limited to 26-bits
// except for h₂₆[1] and h₂₆[4] which are limited to 27-bits.
//
// Note that although each limb is aligned at 26-bit intervals
// they may contain values that exceed 2²⁶ - 1, hence the need
// to carry the excess bits in each limb.
#define REDUCE(h0, h1, h2, h3, h4) \
VESRLG $26, h0, T_0 \
VESRLG $26, h3, T_1 \
VN MOD26, h0, h0 \
VN MOD26, h3, h3 \
VAG T_0, h1, h1 \
VAG T_1, h4, h4 \
VESRLG $26, h1, T_2 \
VESRLG $26, h4, T_3 \
VN MOD26, h1, h1 \
VN MOD26, h4, h4 \
VESLG $2, T_3, T_4 \
VAG T_3, T_4, T_4 \
VAG T_2, h2, h2 \
VAG T_4, h0, h0 \
VESRLG $26, h2, T_0 \
VESRLG $26, h0, T_1 \
VN MOD26, h2, h2 \
VN MOD26, h0, h0 \
VAG T_0, h3, h3 \
VAG T_1, h1, h1 \
VESRLG $26, h3, T_2 \
VN MOD26, h3, h3 \
VAG T_2, h4, h4
// EXPAND splits the 128-bit little-endian values in0 and in1
// into 26-bit big-endian limbs and places the results into
// the first and second lane of d₂₆[0:4] respectively.
//
// The EX0, EX1 and EX2 constants are arrays of byte indices
// for permutation. The permutation both reverses the bytes
// in the input and ensures the bytes are copied into the
// destination limb ready to be shifted into their final
// position.
#define EXPAND(in0, in1, d0, d1, d2, d3, d4) \
VPERM in0, in1, EX0, d0 \
VPERM in0, in1, EX1, d2 \
VPERM in0, in1, EX2, d4 \
VESRLG $26, d0, d1 \
VESRLG $30, d2, d3 \
VESRLG $4, d2, d2 \
VN MOD26, d0, d0 \ // [in0₂₆[0], in1₂₆[0]]
VN MOD26, d3, d3 \ // [in0₂₆[3], in1₂₆[3]]
VN MOD26, d1, d1 \ // [in0₂₆[1], in1₂₆[1]]
VN MOD24, d4, d4 \ // [in0₂₆[4], in1₂₆[4]]
VN MOD26, d2, d2 // [in0₂₆[2], in1₂₆[2]]
// func updateVX(state *macState, msg []byte)
TEXT ·updateVX(SB), NOSPLIT, $0
MOVD state+0(FP), R1
LMG msg+8(FP), R2, R3 // R2=msg_base, R3=msg_len
// load EX0, EX1 and EX2
MOVD $·constants<>(SB), R5
VLM (R5), EX0, EX2
// generate masks
VGMG $(64-24), $63, MOD24 // [0x00ffffff, 0x00ffffff]
VGMG $(64-26), $63, MOD26 // [0x03ffffff, 0x03ffffff]
// load h (accumulator) and r (key) from state
VZERO T_1 // [0, 0]
VL 0(R1), T_0 // [h₆₄[0], h₆₄[1]]
VLEG $0, 16(R1), T_1 // [h₆₄[2], 0]
VL 24(R1), T_2 // [r₆₄[0], r₆₄[1]]
VPDI $0, T_0, T_2, T_3 // [h₆₄[0], r₆₄[0]]
VPDI $5, T_0, T_2, T_4 // [h₆₄[1], r₆₄[1]]
// unpack h and r into 26-bit limbs
// note: h₆₄[2] may have the low 3 bits set, so h₂₆[4] is a 27-bit value
VN MOD26, T_3, H_0 // [h₂₆[0], r₂₆[0]]
VZERO H_1 // [0, 0]
VZERO H_3 // [0, 0]
VGMG $(64-12-14), $(63-12), T_0 // [0x03fff000, 0x03fff000] - 26-bit mask with low 12 bits masked out
VESLG $24, T_1, T_1 // [h₆₄[2]<<24, 0]
VERIMG $-26&63, T_3, MOD26, H_1 // [h₂₆[1], r₂₆[1]]
VESRLG $+52&63, T_3, H_2 // [h₂₆[2], r₂₆[2]] - low 12 bits only
VERIMG $-14&63, T_4, MOD26, H_3 // [h₂₆[1], r₂₆[1]]
VESRLG $40, T_4, H_4 // [h₂₆[4], r₂₆[4]] - low 24 bits only
VERIMG $+12&63, T_4, T_0, H_2 // [h₂₆[2], r₂₆[2]] - complete
VO T_1, H_4, H_4 // [h₂₆[4], r₂₆[4]] - complete
// replicate r across all 4 vector elements
VREPF $3, H_0, R_0 // [r₂₆[0], r₂₆[0], r₂₆[0], r₂₆[0]]
VREPF $3, H_1, R_1 // [r₂₆[1], r₂₆[1], r₂₆[1], r₂₆[1]]
VREPF $3, H_2, R_2 // [r₂₆[2], r₂₆[2], r₂₆[2], r₂₆[2]]
VREPF $3, H_3, R_3 // [r₂₆[3], r₂₆[3], r₂₆[3], r₂₆[3]]
VREPF $3, H_4, R_4 // [r₂₆[4], r₂₆[4], r₂₆[4], r₂₆[4]]
// zero out lane 1 of h
VLEIG $1, $0, H_0 // [h₂₆[0], 0]
VLEIG $1, $0, H_1 // [h₂₆[1], 0]
VLEIG $1, $0, H_2 // [h₂₆[2], 0]
VLEIG $1, $0, H_3 // [h₂₆[3], 0]
VLEIG $1, $0, H_4 // [h₂₆[4], 0]
// calculate 5r (ignore least significant limb)
VREPIF $5, T_0
VMLF T_0, R_1, R5_1 // [5r₂₆[1], 5r₂₆[1], 5r₂₆[1], 5r₂₆[1]]
VMLF T_0, R_2, R5_2 // [5r₂₆[2], 5r₂₆[2], 5r₂₆[2], 5r₂₆[2]]
VMLF T_0, R_3, R5_3 // [5r₂₆[3], 5r₂₆[3], 5r₂₆[3], 5r₂₆[3]]
VMLF T_0, R_4, R5_4 // [5r₂₆[4], 5r₂₆[4], 5r₂₆[4], 5r₂₆[4]]
// skip r² calculation if we are only calculating one block
CMPBLE R3, $16, skip
// calculate r²
MULTIPLY(R_0, R_1, R_2, R_3, R_4, R_0, R_1, R_2, R_3, R_4, R5_1, R5_2, R5_3, R5_4, M_0, M_1, M_2, M_3, M_4)
REDUCE(M_0, M_1, M_2, M_3, M_4)
VGBM $0x0f0f, T_0
VERIMG $0, M_0, T_0, R_0 // [r₂₆[0], r²₂₆[0], r₂₆[0], r²₂₆[0]]
VERIMG $0, M_1, T_0, R_1 // [r₂₆[1], r²₂₆[1], r₂₆[1], r²₂₆[1]]
VERIMG $0, M_2, T_0, R_2 // [r₂₆[2], r²₂₆[2], r₂₆[2], r²₂₆[2]]
VERIMG $0, M_3, T_0, R_3 // [r₂₆[3], r²₂₆[3], r₂₆[3], r²₂₆[3]]
VERIMG $0, M_4, T_0, R_4 // [r₂₆[4], r²₂₆[4], r₂₆[4], r²₂₆[4]]
// calculate 5r² (ignore least significant limb)
VREPIF $5, T_0
VMLF T_0, R_1, R5_1 // [5r₂₆[1], 5r²₂₆[1], 5r₂₆[1], 5r²₂₆[1]]
VMLF T_0, R_2, R5_2 // [5r₂₆[2], 5r²₂₆[2], 5r₂₆[2], 5r²₂₆[2]]
VMLF T_0, R_3, R5_3 // [5r₂₆[3], 5r²₂₆[3], 5r₂₆[3], 5r²₂₆[3]]
VMLF T_0, R_4, R5_4 // [5r₂₆[4], 5r²₂₆[4], 5r₂₆[4], 5r²₂₆[4]]
loop:
CMPBLE R3, $32, b2 // 2 or fewer blocks remaining, need to change key coefficients
// load next 2 blocks from message
VLM (R2), T_0, T_1
// update message slice
SUB $32, R3
MOVD $32(R2), R2
// unpack message blocks into 26-bit big-endian limbs
EXPAND(T_0, T_1, M_0, M_1, M_2, M_3, M_4)
// add 2¹²⁸ to each message block value
VLEIB $4, $1, M_4
VLEIB $12, $1, M_4
multiply:
// accumulate the incoming message
VAG H_0, M_0, M_0
VAG H_3, M_3, M_3
VAG H_1, M_1, M_1
VAG H_4, M_4, M_4
VAG H_2, M_2, M_2
// multiply the accumulator by the key coefficient
MULTIPLY(M_0, M_1, M_2, M_3, M_4, R_0, R_1, R_2, R_3, R_4, R5_1, R5_2, R5_3, R5_4, H_0, H_1, H_2, H_3, H_4)
// carry and partially reduce the partial products
REDUCE(H_0, H_1, H_2, H_3, H_4)
CMPBNE R3, $0, loop
finish:
// sum lane 0 and lane 1 and put the result in lane 1
VZERO T_0
VSUMQG H_0, T_0, H_0
VSUMQG H_3, T_0, H_3
VSUMQG H_1, T_0, H_1
VSUMQG H_4, T_0, H_4
VSUMQG H_2, T_0, H_2
// reduce again after summation
// TODO(mundaym): there might be a more efficient way to do this
// now that we only have 1 active lane. For example, we could
// simultaneously pack the values as we reduce them.
REDUCE(H_0, H_1, H_2, H_3, H_4)
// carry h[1] through to h[4] so that only h[4] can exceed 2²⁶ - 1
// TODO(mundaym): in testing this final carry was unnecessary.
// Needs a proof before it can be removed though.
VESRLG $26, H_1, T_1
VN MOD26, H_1, H_1
VAQ T_1, H_2, H_2
VESRLG $26, H_2, T_2
VN MOD26, H_2, H_2
VAQ T_2, H_3, H_3
VESRLG $26, H_3, T_3
VN MOD26, H_3, H_3
VAQ T_3, H_4, H_4
// h is now < 2(2¹³⁰ - 5)
// Pack each lane in h₂₆[0:4] into h₁₂₈[0:1].
VESLG $26, H_1, H_1
VESLG $26, H_3, H_3
VO H_0, H_1, H_0
VO H_2, H_3, H_2
VESLG $4, H_2, H_2
VLEIB $7, $48, H_1
VSLB H_1, H_2, H_2
VO H_0, H_2, H_0
VLEIB $7, $104, H_1
VSLB H_1, H_4, H_3
VO H_3, H_0, H_0
VLEIB $7, $24, H_1
VSRLB H_1, H_4, H_1
// update state
VSTEG $1, H_0, 0(R1)
VSTEG $0, H_0, 8(R1)
VSTEG $1, H_1, 16(R1)
RET
b2: // 2 or fewer blocks remaining
CMPBLE R3, $16, b1
// Load the 2 remaining blocks (17-32 bytes remaining).
MOVD $-17(R3), R0 // index of final byte to load modulo 16
VL (R2), T_0 // load full 16 byte block
VLL R0, 16(R2), T_1 // load final (possibly partial) block and pad with zeros to 16 bytes
// The Poly1305 algorithm requires that a 1 bit be appended to
// each message block. If the final block is less than 16 bytes
// long then it is easiest to insert the 1 before the message
// block is split into 26-bit limbs. If, on the other hand, the
// final message block is 16 bytes long then we append the 1 bit
// after expansion as normal.
MOVBZ $1, R0
MOVD $-16(R3), R3 // index of byte in last block to insert 1 at (could be 16)
CMPBEQ R3, $16, 2(PC) // skip the insertion if the final block is 16 bytes long
VLVGB R3, R0, T_1 // insert 1 into the byte at index R3
// Split both blocks into 26-bit limbs in the appropriate lanes.
EXPAND(T_0, T_1, M_0, M_1, M_2, M_3, M_4)
// Append a 1 byte to the end of the second to last block.
VLEIB $4, $1, M_4
// Append a 1 byte to the end of the last block only if it is a
// full 16 byte block.
CMPBNE R3, $16, 2(PC)
VLEIB $12, $1, M_4
// Finally, set up the coefficients for the final multiplication.
// We have previously saved r and 5r in the 32-bit even indexes
// of the R_[0-4] and R5_[1-4] coefficient registers.
//
// We want lane 0 to be multiplied by r² so that can be kept the
// same. We want lane 1 to be multiplied by r so we need to move
// the saved r value into the 32-bit odd index in lane 1 by
// rotating the 64-bit lane by 32.
VGBM $0x00ff, T_0 // [0, 0xffffffffffffffff] - mask lane 1 only
VERIMG $32, R_0, T_0, R_0 // [_, r²₂₆[0], _, r₂₆[0]]
VERIMG $32, R_1, T_0, R_1 // [_, r²₂₆[1], _, r₂₆[1]]
VERIMG $32, R_2, T_0, R_2 // [_, r²₂₆[2], _, r₂₆[2]]
VERIMG $32, R_3, T_0, R_3 // [_, r²₂₆[3], _, r₂₆[3]]
VERIMG $32, R_4, T_0, R_4 // [_, r²₂₆[4], _, r₂₆[4]]
VERIMG $32, R5_1, T_0, R5_1 // [_, 5r²₂₆[1], _, 5r₂₆[1]]
VERIMG $32, R5_2, T_0, R5_2 // [_, 5r²₂₆[2], _, 5r₂₆[2]]
VERIMG $32, R5_3, T_0, R5_3 // [_, 5r²₂₆[3], _, 5r₂₆[3]]
VERIMG $32, R5_4, T_0, R5_4 // [_, 5r²₂₆[4], _, 5r₂₆[4]]
MOVD $0, R3
BR multiply
skip:
CMPBEQ R3, $0, finish
b1: // 1 block remaining
// Load the final block (1-16 bytes). This will be placed into
// lane 0.
MOVD $-1(R3), R0
VLL R0, (R2), T_0 // pad to 16 bytes with zeros
// The Poly1305 algorithm requires that a 1 bit be appended to
// each message block. If the final block is less than 16 bytes
// long then it is easiest to insert the 1 before the message
// block is split into 26-bit limbs. If, on the other hand, the
// final message block is 16 bytes long then we append the 1 bit
// after expansion as normal.
MOVBZ $1, R0
CMPBEQ R3, $16, 2(PC)
VLVGB R3, R0, T_0
// Set the message block in lane 1 to the value 0 so that it
// can be accumulated without affecting the final result.
VZERO T_1
// Split the final message block into 26-bit limbs in lane 0.
// Lane 1 will be contain 0.
EXPAND(T_0, T_1, M_0, M_1, M_2, M_3, M_4)
// Append a 1 byte to the end of the last block only if it is a
// full 16 byte block.
CMPBNE R3, $16, 2(PC)
VLEIB $4, $1, M_4
// We have previously saved r and 5r in the 32-bit even indexes
// of the R_[0-4] and R5_[1-4] coefficient registers.
//
// We want lane 0 to be multiplied by r so we need to move the
// saved r value into the 32-bit odd index in lane 0. We want
// lane 1 to be set to the value 1. This makes multiplication
// a no-op. We do this by setting lane 1 in every register to 0
// and then just setting the 32-bit index 3 in R_0 to 1.
VZERO T_0
MOVD $0, R0
MOVD $0x10111213, R12
VLVGP R12, R0, T_1 // [_, 0x10111213, _, 0x00000000]
VPERM T_0, R_0, T_1, R_0 // [_, r₂₆[0], _, 0]
VPERM T_0, R_1, T_1, R_1 // [_, r₂₆[1], _, 0]
VPERM T_0, R_2, T_1, R_2 // [_, r₂₆[2], _, 0]
VPERM T_0, R_3, T_1, R_3 // [_, r₂₆[3], _, 0]
VPERM T_0, R_4, T_1, R_4 // [_, r₂₆[4], _, 0]
VPERM T_0, R5_1, T_1, R5_1 // [_, 5r₂₆[1], _, 0]
VPERM T_0, R5_2, T_1, R5_2 // [_, 5r₂₆[2], _, 0]
VPERM T_0, R5_3, T_1, R5_3 // [_, 5r₂₆[3], _, 0]
VPERM T_0, R5_4, T_1, R5_4 // [_, 5r₂₆[4], _, 0]
// Set the value of lane 1 to be 1.
VLEIF $3, $1, R_0 // [_, r₂₆[0], _, 1]
MOVD $0, R3
BR multiply

786
pkg/proto/ssh/kex.go
View File

@ -1,786 +0,0 @@
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/subtle"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"golang.org/x/crypto/curve25519"
)
const (
kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1"
kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
kexAlgoDH14SHA256 = "diffie-hellman-group14-sha256"
kexAlgoDH16SHA512 = "diffie-hellman-group16-sha512"
kexAlgoECDH256 = "ecdh-sha2-nistp256"
kexAlgoECDH384 = "ecdh-sha2-nistp384"
kexAlgoECDH521 = "ecdh-sha2-nistp521"
kexAlgoCurve25519SHA256LibSSH = "curve25519-sha256@libssh.org"
kexAlgoCurve25519SHA256 = "curve25519-sha256"
// For the following kex only the client half contains a production
// ready implementation. The server half only consists of a minimal
// implementation to satisfy the automated tests.
kexAlgoDHGEXSHA1 = "diffie-hellman-group-exchange-sha1"
kexAlgoDHGEXSHA256 = "diffie-hellman-group-exchange-sha256"
)
// kexResult captures the outcome of a key exchange.
type kexResult struct {
// Session hash. See also RFC 4253, section 8.
H []byte
// Shared secret. See also RFC 4253, section 8.
K []byte
// Host key as hashed into H.
HostKey []byte
// Signature of H.
Signature []byte
// A cryptographic hash function that matches the security
// level of the key exchange algorithm. It is used for
// calculating H, and for deriving keys from H and K.
Hash crypto.Hash
// The session ID, which is the first H computed. This is used
// to derive key material inside the transport.
SessionID []byte
}
// handshakeMagics contains data that is always included in the
// session hash.
type handshakeMagics struct {
clientVersion, serverVersion []byte
clientKexInit, serverKexInit []byte
}
func (m *handshakeMagics) write(w io.Writer) {
writeString(w, m.clientVersion)
writeString(w, m.serverVersion)
writeString(w, m.clientKexInit)
writeString(w, m.serverKexInit)
}
// kexAlgorithm abstracts different key exchange algorithms.
type kexAlgorithm interface {
// Server runs server-side key agreement, signing the result
// with a hostkey. algo is the negotiated algorithm, and may
// be a certificate type.
Server(p packetConn, rand io.Reader, magics *handshakeMagics, s AlgorithmSigner, algo string) (*kexResult, error)
// Client runs the client-side key agreement. Caller is
// responsible for verifying the host key signature.
Client(p packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error)
}
// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement.
type dhGroup struct {
g, p, pMinus1 *big.Int
hashFunc crypto.Hash
}
func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) {
if theirPublic.Cmp(bigOne) <= 0 || theirPublic.Cmp(group.pMinus1) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
return new(big.Int).Exp(theirPublic, myPrivate, group.p), nil
}
func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
var x *big.Int
for {
var err error
if x, err = rand.Int(randSource, group.pMinus1); err != nil {
return nil, err
}
if x.Sign() > 0 {
break
}
}
X := new(big.Int).Exp(group.g, x, group.p)
kexDHInit := kexDHInitMsg{
X: X,
}
if err := c.writePacket(Marshal(&kexDHInit)); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var kexDHReply kexDHReplyMsg
if err = Unmarshal(packet, &kexDHReply); err != nil {
return nil, err
}
ki, err := group.diffieHellman(kexDHReply.Y, x)
if err != nil {
return nil, err
}
h := group.hashFunc.New()
magics.write(h)
writeString(h, kexDHReply.HostKey)
writeInt(h, X)
writeInt(h, kexDHReply.Y)
K := make([]byte, intLength(ki))
marshalInt(K, ki)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: kexDHReply.HostKey,
Signature: kexDHReply.Signature,
Hash: group.hashFunc,
}, nil
}
func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return
}
var kexDHInit kexDHInitMsg
if err = Unmarshal(packet, &kexDHInit); err != nil {
return
}
var y *big.Int
for {
if y, err = rand.Int(randSource, group.pMinus1); err != nil {
return
}
if y.Sign() > 0 {
break
}
}
Y := new(big.Int).Exp(group.g, y, group.p)
ki, err := group.diffieHellman(kexDHInit.X, y)
if err != nil {
return nil, err
}
hostKeyBytes := priv.PublicKey().Marshal()
h := group.hashFunc.New()
magics.write(h)
writeString(h, hostKeyBytes)
writeInt(h, kexDHInit.X)
writeInt(h, Y)
K := make([]byte, intLength(ki))
marshalInt(K, ki)
h.Write(K)
H := h.Sum(nil)
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, randSource, H, algo)
if err != nil {
return nil, err
}
kexDHReply := kexDHReplyMsg{
HostKey: hostKeyBytes,
Y: Y,
Signature: sig,
}
packet = Marshal(&kexDHReply)
err = c.writePacket(packet)
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: group.hashFunc,
}, err
}
// ecdh performs Elliptic Curve Diffie-Hellman key exchange as
// described in RFC 5656, section 4.
type ecdh struct {
curve elliptic.Curve
}
func (kex *ecdh) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
ephKey, err := ecdsa.GenerateKey(kex.curve, rand)
if err != nil {
return nil, err
}
kexInit := kexECDHInitMsg{
ClientPubKey: elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y),
}
serialized := Marshal(&kexInit)
if err := c.writePacket(serialized); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var reply kexECDHReplyMsg
if err = Unmarshal(packet, &reply); err != nil {
return nil, err
}
x, y, err := unmarshalECKey(kex.curve, reply.EphemeralPubKey)
if err != nil {
return nil, err
}
// generate shared secret
secret, _ := kex.curve.ScalarMult(x, y, ephKey.D.Bytes())
h := ecHash(kex.curve).New()
magics.write(h)
writeString(h, reply.HostKey)
writeString(h, kexInit.ClientPubKey)
writeString(h, reply.EphemeralPubKey)
K := make([]byte, intLength(secret))
marshalInt(K, secret)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: reply.HostKey,
Signature: reply.Signature,
Hash: ecHash(kex.curve),
}, nil
}
// unmarshalECKey parses and checks an EC key.
func unmarshalECKey(curve elliptic.Curve, pubkey []byte) (x, y *big.Int, err error) {
x, y = elliptic.Unmarshal(curve, pubkey)
if x == nil {
return nil, nil, errors.New("ssh: elliptic.Unmarshal failure")
}
if !validateECPublicKey(curve, x, y) {
return nil, nil, errors.New("ssh: public key not on curve")
}
return x, y, nil
}
// validateECPublicKey checks that the point is a valid public key for
// the given curve. See [SEC1], 3.2.2
func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool {
if x.Sign() == 0 && y.Sign() == 0 {
return false
}
if x.Cmp(curve.Params().P) >= 0 {
return false
}
if y.Cmp(curve.Params().P) >= 0 {
return false
}
if !curve.IsOnCurve(x, y) {
return false
}
// We don't check if N * PubKey == 0, since
//
// - the NIST curves have cofactor = 1, so this is implicit.
// (We don't foresee an implementation that supports non NIST
// curves)
//
// - for ephemeral keys, we don't need to worry about small
// subgroup attacks.
return true
}
func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var kexECDHInit kexECDHInitMsg
if err = Unmarshal(packet, &kexECDHInit); err != nil {
return nil, err
}
clientX, clientY, err := unmarshalECKey(kex.curve, kexECDHInit.ClientPubKey)
if err != nil {
return nil, err
}
// We could cache this key across multiple users/multiple
// connection attempts, but the benefit is small. OpenSSH
// generates a new key for each incoming connection.
ephKey, err := ecdsa.GenerateKey(kex.curve, rand)
if err != nil {
return nil, err
}
hostKeyBytes := priv.PublicKey().Marshal()
serializedEphKey := elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y)
// generate shared secret
secret, _ := kex.curve.ScalarMult(clientX, clientY, ephKey.D.Bytes())
h := ecHash(kex.curve).New()
magics.write(h)
writeString(h, hostKeyBytes)
writeString(h, kexECDHInit.ClientPubKey)
writeString(h, serializedEphKey)
K := make([]byte, intLength(secret))
marshalInt(K, secret)
h.Write(K)
H := h.Sum(nil)
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, rand, H, algo)
if err != nil {
return nil, err
}
reply := kexECDHReplyMsg{
EphemeralPubKey: serializedEphKey,
HostKey: hostKeyBytes,
Signature: sig,
}
serialized := Marshal(&reply)
if err := c.writePacket(serialized); err != nil {
return nil, err
}
return &kexResult{
H: H,
K: K,
HostKey: reply.HostKey,
Signature: sig,
Hash: ecHash(kex.curve),
}, nil
}
// ecHash returns the hash to match the given elliptic curve, see RFC
// 5656, section 6.2.1
func ecHash(curve elliptic.Curve) crypto.Hash {
bitSize := curve.Params().BitSize
switch {
case bitSize <= 256:
return crypto.SHA256
case bitSize <= 384:
return crypto.SHA384
}
return crypto.SHA512
}
var kexAlgoMap = map[string]kexAlgorithm{}
func init() {
// This is the group called diffie-hellman-group1-sha1 in
// RFC 4253 and Oakley Group 2 in RFC 2409.
p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16)
kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
hashFunc: crypto.SHA1,
}
// This are the groups called diffie-hellman-group14-sha1 and
// diffie-hellman-group14-sha256 in RFC 4253 and RFC 8268,
// and Oakley Group 14 in RFC 3526.
p, _ = new(big.Int).SetString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
group14 := &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
}
kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA1,
}
kexAlgoMap[kexAlgoDH14SHA256] = &dhGroup{
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA256,
}
// This is the group called diffie-hellman-group16-sha512 in RFC
// 8268 and Oakley Group 16 in RFC 3526.
p, _ = new(big.Int).SetString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
kexAlgoMap[kexAlgoDH16SHA512] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
hashFunc: crypto.SHA512,
}
kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()}
kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()}
kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()}
kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{}
kexAlgoMap[kexAlgoCurve25519SHA256LibSSH] = &curve25519sha256{}
kexAlgoMap[kexAlgoDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1}
kexAlgoMap[kexAlgoDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256}
}
// curve25519sha256 implements the curve25519-sha256 (formerly known as
// curve25519-sha256@libssh.org) key exchange method, as described in RFC 8731.
type curve25519sha256 struct{}
type curve25519KeyPair struct {
priv [32]byte
pub [32]byte
}
func (kp *curve25519KeyPair) generate(rand io.Reader) error {
if _, err := io.ReadFull(rand, kp.priv[:]); err != nil {
return err
}
curve25519.ScalarBaseMult(&kp.pub, &kp.priv)
return nil
}
// curve25519Zeros is just an array of 32 zero bytes so that we have something
// convenient to compare against in order to reject curve25519 points with the
// wrong order.
var curve25519Zeros [32]byte
func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
var kp curve25519KeyPair
if err := kp.generate(rand); err != nil {
return nil, err
}
if err := c.writePacket(Marshal(&kexECDHInitMsg{kp.pub[:]})); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var reply kexECDHReplyMsg
if err = Unmarshal(packet, &reply); err != nil {
return nil, err
}
if len(reply.EphemeralPubKey) != 32 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
}
var servPub, secret [32]byte
copy(servPub[:], reply.EphemeralPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &servPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
}
h := crypto.SHA256.New()
magics.write(h)
writeString(h, reply.HostKey)
writeString(h, kp.pub[:])
writeString(h, reply.EphemeralPubKey)
ki := new(big.Int).SetBytes(secret[:])
K := make([]byte, intLength(ki))
marshalInt(K, ki)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: reply.HostKey,
Signature: reply.Signature,
Hash: crypto.SHA256,
}, nil
}
func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return
}
var kexInit kexECDHInitMsg
if err = Unmarshal(packet, &kexInit); err != nil {
return
}
if len(kexInit.ClientPubKey) != 32 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
}
var kp curve25519KeyPair
if err := kp.generate(rand); err != nil {
return nil, err
}
var clientPub, secret [32]byte
copy(clientPub[:], kexInit.ClientPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &clientPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
}
hostKeyBytes := priv.PublicKey().Marshal()
h := crypto.SHA256.New()
magics.write(h)
writeString(h, hostKeyBytes)
writeString(h, kexInit.ClientPubKey)
writeString(h, kp.pub[:])
ki := new(big.Int).SetBytes(secret[:])
K := make([]byte, intLength(ki))
marshalInt(K, ki)
h.Write(K)
H := h.Sum(nil)
sig, err := signAndMarshal(priv, rand, H, algo)
if err != nil {
return nil, err
}
reply := kexECDHReplyMsg{
EphemeralPubKey: kp.pub[:],
HostKey: hostKeyBytes,
Signature: sig,
}
if err := c.writePacket(Marshal(&reply)); err != nil {
return nil, err
}
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: crypto.SHA256,
}, nil
}
// dhGEXSHA implements the diffie-hellman-group-exchange-sha1 and
// diffie-hellman-group-exchange-sha256 key agreement protocols,
// as described in RFC 4419
type dhGEXSHA struct {
hashFunc crypto.Hash
}
const (
dhGroupExchangeMinimumBits = 2048
dhGroupExchangePreferredBits = 2048
dhGroupExchangeMaximumBits = 8192
)
func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
// Send GexRequest
kexDHGexRequest := kexDHGexRequestMsg{
MinBits: dhGroupExchangeMinimumBits,
PreferedBits: dhGroupExchangePreferredBits,
MaxBits: dhGroupExchangeMaximumBits,
}
if err := c.writePacket(Marshal(&kexDHGexRequest)); err != nil {
return nil, err
}
// Receive GexGroup
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var msg kexDHGexGroupMsg
if err = Unmarshal(packet, &msg); err != nil {
return nil, err
}
// reject if p's bit length < dhGroupExchangeMinimumBits or > dhGroupExchangeMaximumBits
if msg.P.BitLen() < dhGroupExchangeMinimumBits || msg.P.BitLen() > dhGroupExchangeMaximumBits {
return nil, fmt.Errorf("ssh: server-generated gex p is out of range (%d bits)", msg.P.BitLen())
}
// Check if g is safe by verifying that 1 < g < p-1
pMinusOne := new(big.Int).Sub(msg.P, bigOne)
if msg.G.Cmp(bigOne) <= 0 || msg.G.Cmp(pMinusOne) >= 0 {
return nil, fmt.Errorf("ssh: server provided gex g is not safe")
}
// Send GexInit
pHalf := new(big.Int).Rsh(msg.P, 1)
x, err := rand.Int(randSource, pHalf)
if err != nil {
return nil, err
}
X := new(big.Int).Exp(msg.G, x, msg.P)
kexDHGexInit := kexDHGexInitMsg{
X: X,
}
if err := c.writePacket(Marshal(&kexDHGexInit)); err != nil {
return nil, err
}
// Receive GexReply
packet, err = c.readPacket()
if err != nil {
return nil, err
}
var kexDHGexReply kexDHGexReplyMsg
if err = Unmarshal(packet, &kexDHGexReply); err != nil {
return nil, err
}
if kexDHGexReply.Y.Cmp(bigOne) <= 0 || kexDHGexReply.Y.Cmp(pMinusOne) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
kInt := new(big.Int).Exp(kexDHGexReply.Y, x, msg.P)
// Check if k is safe by verifying that k > 1 and k < p - 1
if kInt.Cmp(bigOne) <= 0 || kInt.Cmp(pMinusOne) >= 0 {
return nil, fmt.Errorf("ssh: derived k is not safe")
}
h := gex.hashFunc.New()
magics.write(h)
writeString(h, kexDHGexReply.HostKey)
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
writeInt(h, msg.P)
writeInt(h, msg.G)
writeInt(h, X)
writeInt(h, kexDHGexReply.Y)
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: kexDHGexReply.HostKey,
Signature: kexDHGexReply.Signature,
Hash: gex.hashFunc,
}, nil
}
// Server half implementation of the Diffie Hellman Key Exchange with SHA1 and SHA256.
//
// This is a minimal implementation to satisfy the automated tests.
func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
// Receive GexRequest
packet, err := c.readPacket()
if err != nil {
return
}
var kexDHGexRequest kexDHGexRequestMsg
if err = Unmarshal(packet, &kexDHGexRequest); err != nil {
return
}
// Send GexGroup
// This is the group called diffie-hellman-group14-sha1 in RFC
// 4253 and Oakley Group 14 in RFC 3526.
p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF", 16)
g := big.NewInt(2)
msg := &kexDHGexGroupMsg{
P: p,
G: g,
}
if err := c.writePacket(Marshal(msg)); err != nil {
return nil, err
}
// Receive GexInit
packet, err = c.readPacket()
if err != nil {
return
}
var kexDHGexInit kexDHGexInitMsg
if err = Unmarshal(packet, &kexDHGexInit); err != nil {
return
}
pHalf := new(big.Int).Rsh(p, 1)
y, err := rand.Int(randSource, pHalf)
if err != nil {
return
}
Y := new(big.Int).Exp(g, y, p)
pMinusOne := new(big.Int).Sub(p, bigOne)
if kexDHGexInit.X.Cmp(bigOne) <= 0 || kexDHGexInit.X.Cmp(pMinusOne) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
kInt := new(big.Int).Exp(kexDHGexInit.X, y, p)
hostKeyBytes := priv.PublicKey().Marshal()
h := gex.hashFunc.New()
magics.write(h)
writeString(h, hostKeyBytes)
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
writeInt(h, p)
writeInt(h, g)
writeInt(h, kexDHGexInit.X)
writeInt(h, Y)
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
H := h.Sum(nil)
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, randSource, H, algo)
if err != nil {
return nil, err
}
kexDHGexReply := kexDHGexReplyMsg{
HostKey: hostKeyBytes,
Y: Y,
Signature: sig,
}
packet = Marshal(&kexDHGexReply)
err = c.writePacket(packet)
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: gex.hashFunc,
}, err
}

1728
pkg/proto/ssh/keys.go
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File diff suppressed because it is too large Load Diff

540
pkg/proto/ssh/knownhosts/knownhosts.go
View File

@ -1,540 +0,0 @@
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package knownhosts implements a parser for the OpenSSH known_hosts
// host key database, and provides utility functions for writing
// OpenSSH compliant known_hosts files.
package knownhosts
import (
"bufio"
"bytes"
"crypto/hmac"
"crypto/rand"
"crypto/sha1"
"encoding/base64"
"errors"
"fmt"
"io"
"net"
"os"
"strings"
"github.com/Neur0toxine/sshpoke/pkg/proto/ssh"
)
// See the sshd manpage
// (http://man.openbsd.org/sshd#SSH_KNOWN_HOSTS_FILE_FORMAT) for
// background.
type addr struct{ host, port string }
func (a *addr) String() string {
h := a.host
if strings.Contains(h, ":") {
h = "[" + h + "]"
}
return h + ":" + a.port
}
type matcher interface {
match(addr) bool
}
type hostPattern struct {
negate bool
addr addr
}
func (p *hostPattern) String() string {
n := ""
if p.negate {
n = "!"
}
return n + p.addr.String()
}
type hostPatterns []hostPattern
func (ps hostPatterns) match(a addr) bool {
matched := false
for _, p := range ps {
if !p.match(a) {
continue
}
if p.negate {
return false
}
matched = true
}
return matched
}
// See
// https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/addrmatch.c
// The matching of * has no regard for separators, unlike filesystem globs
func wildcardMatch(pat []byte, str []byte) bool {
for {
if len(pat) == 0 {
return len(str) == 0
}
if len(str) == 0 {
return false
}
if pat[0] == '*' {
if len(pat) == 1 {
return true
}
for j := range str {
if wildcardMatch(pat[1:], str[j:]) {
return true
}
}
return false
}
if pat[0] == '?' || pat[0] == str[0] {
pat = pat[1:]
str = str[1:]
} else {
return false
}
}
}
func (p *hostPattern) match(a addr) bool {
return wildcardMatch([]byte(p.addr.host), []byte(a.host)) && p.addr.port == a.port
}
type keyDBLine struct {
cert bool
matcher matcher
knownKey KnownKey
}
func serialize(k ssh.PublicKey) string {
return k.Type() + " " + base64.StdEncoding.EncodeToString(k.Marshal())
}
func (l *keyDBLine) match(a addr) bool {
return l.matcher.match(a)
}
type hostKeyDB struct {
// Serialized version of revoked keys
revoked map[string]*KnownKey
lines []keyDBLine
}
func newHostKeyDB() *hostKeyDB {
db := &hostKeyDB{
revoked: make(map[string]*KnownKey),
}
return db
}
func keyEq(a, b ssh.PublicKey) bool {
return bytes.Equal(a.Marshal(), b.Marshal())
}
// IsHostAuthority can be used as a callback in ssh.CertChecker
func (db *hostKeyDB) IsHostAuthority(remote ssh.PublicKey, address string) bool {
h, p, err := net.SplitHostPort(address)
if err != nil {
return false
}
a := addr{host: h, port: p}
for _, l := range db.lines {
if l.cert && keyEq(l.knownKey.Key, remote) && l.match(a) {
return true
}
}
return false
}
// IsRevoked can be used as a callback in ssh.CertChecker
func (db *hostKeyDB) IsRevoked(key *ssh.Certificate) bool {
_, ok := db.revoked[string(key.Marshal())]
return ok
}
const markerCert = "@cert-authority"
const markerRevoked = "@revoked"
func nextWord(line []byte) (string, []byte) {
i := bytes.IndexAny(line, "\t ")
if i == -1 {
return string(line), nil
}
return string(line[:i]), bytes.TrimSpace(line[i:])
}
func parseLine(line []byte) (marker, host string, key ssh.PublicKey, err error) {
if w, next := nextWord(line); w == markerCert || w == markerRevoked {
marker = w
line = next
}
host, line = nextWord(line)
if len(line) == 0 {
return "", "", nil, errors.New("knownhosts: missing host pattern")
}
// ignore the keytype as it's in the key blob anyway.
_, line = nextWord(line)
if len(line) == 0 {
return "", "", nil, errors.New("knownhosts: missing key type pattern")
}
keyBlob, _ := nextWord(line)
keyBytes, err := base64.StdEncoding.DecodeString(keyBlob)
if err != nil {
return "", "", nil, err
}
key, err = ssh.ParsePublicKey(keyBytes)
if err != nil {
return "", "", nil, err
}
return marker, host, key, nil
}
func (db *hostKeyDB) parseLine(line []byte, filename string, linenum int) error {
marker, pattern, key, err := parseLine(line)
if err != nil {
return err
}
if marker == markerRevoked {
db.revoked[string(key.Marshal())] = &KnownKey{
Key: key,
Filename: filename,
Line: linenum,
}
return nil
}
entry := keyDBLine{
cert: marker == markerCert,
knownKey: KnownKey{
Filename: filename,
Line: linenum,
Key: key,
},
}
if pattern[0] == '|' {
entry.matcher, err = newHashedHost(pattern)
} else {
entry.matcher, err = newHostnameMatcher(pattern)
}
if err != nil {
return err
}
db.lines = append(db.lines, entry)
return nil
}
func newHostnameMatcher(pattern string) (matcher, error) {
var hps hostPatterns
for _, p := range strings.Split(pattern, ",") {
if len(p) == 0 {
continue
}
var a addr
var negate bool
if p[0] == '!' {
negate = true
p = p[1:]
}
if len(p) == 0 {
return nil, errors.New("knownhosts: negation without following hostname")
}
var err error
if p[0] == '[' {
a.host, a.port, err = net.SplitHostPort(p)
if err != nil {
return nil, err
}
} else {
a.host, a.port, err = net.SplitHostPort(p)
if err != nil {
a.host = p
a.port = "22"
}
}
hps = append(hps, hostPattern{
negate: negate,
addr: a,
})
}
return hps, nil
}
// KnownKey represents a key declared in a known_hosts file.
type KnownKey struct {
Key ssh.PublicKey
Filename string
Line int
}
func (k *KnownKey) String() string {
return fmt.Sprintf("%s:%d: %s", k.Filename, k.Line, serialize(k.Key))
}
// KeyError is returned if we did not find the key in the host key
// database, or there was a mismatch. Typically, in batch
// applications, this should be interpreted as failure. Interactive
// applications can offer an interactive prompt to the user.
type KeyError struct {
// Want holds the accepted host keys. For each key algorithm,
// there can be one hostkey. If Want is empty, the host is
// unknown. If Want is non-empty, there was a mismatch, which
// can signify a MITM attack.
Want []KnownKey
}
func (u *KeyError) Error() string {
if len(u.Want) == 0 {
return "knownhosts: key is unknown"
}
return "knownhosts: key mismatch"
}
// RevokedError is returned if we found a key that was revoked.
type RevokedError struct {
Revoked KnownKey
}
func (r *RevokedError) Error() string {
return "knownhosts: key is revoked"
}
// check checks a key against the host database. This should not be
// used for verifying certificates.
func (db *hostKeyDB) check(address string, remote net.Addr, remoteKey ssh.PublicKey) error {
if revoked := db.revoked[string(remoteKey.Marshal())]; revoked != nil {
return &RevokedError{Revoked: *revoked}
}
host, port, err := net.SplitHostPort(remote.String())
if err != nil {
return fmt.Errorf("knownhosts: SplitHostPort(%s): %v", remote, err)
}
hostToCheck := addr{host, port}
if address != "" {
// Give preference to the hostname if available.
host, port, err := net.SplitHostPort(address)
if err != nil {
return fmt.Errorf("knownhosts: SplitHostPort(%s): %v", address, err)
}
hostToCheck = addr{host, port}
}
return db.checkAddr(hostToCheck, remoteKey)
}
// checkAddr checks if we can find the given public key for the
// given address. If we only find an entry for the IP address,
// or only the hostname, then this still succeeds.
func (db *hostKeyDB) checkAddr(a addr, remoteKey ssh.PublicKey) error {
// TODO(hanwen): are these the right semantics? What if there
// is just a key for the IP address, but not for the
// hostname?
// Algorithm => key.
knownKeys := map[string]KnownKey{}
for _, l := range db.lines {
if l.match(a) {
typ := l.knownKey.Key.Type()
if _, ok := knownKeys[typ]; !ok {
knownKeys[typ] = l.knownKey
}
}
}
keyErr := &KeyError{}
for _, v := range knownKeys {
keyErr.Want = append(keyErr.Want, v)
}
// Unknown remote host.
if len(knownKeys) == 0 {
return keyErr
}
// If the remote host starts using a different, unknown key type, we
// also interpret that as a mismatch.
if known, ok := knownKeys[remoteKey.Type()]; !ok || !keyEq(known.Key, remoteKey) {
return keyErr
}
return nil
}
// The Read function parses file contents.
func (db *hostKeyDB) Read(r io.Reader, filename string) error {
scanner := bufio.NewScanner(r)
lineNum := 0
for scanner.Scan() {
lineNum++
line := scanner.Bytes()
line = bytes.TrimSpace(line)
if len(line) == 0 || line[0] == '#' {
continue
}
if err := db.parseLine(line, filename, lineNum); err != nil {
return fmt.Errorf("knownhosts: %s:%d: %v", filename, lineNum, err)
}
}
return scanner.Err()
}
// New creates a host key callback from the given OpenSSH host key
// files. The returned callback is for use in
// ssh.ClientConfig.HostKeyCallback. By preference, the key check
// operates on the hostname if available, i.e. if a server changes its
// IP address, the host key check will still succeed, even though a
// record of the new IP address is not available.
func New(files ...string) (ssh.HostKeyCallback, error) {
db := newHostKeyDB()
for _, fn := range files {
f, err := os.Open(fn)
if err != nil {
return nil, err
}
defer f.Close()
if err := db.Read(f, fn); err != nil {
return nil, err
}
}
var certChecker ssh.CertChecker
certChecker.IsHostAuthority = db.IsHostAuthority
certChecker.IsRevoked = db.IsRevoked
certChecker.HostKeyFallback = db.check
return certChecker.CheckHostKey, nil
}
// Normalize normalizes an address into the form used in known_hosts
func Normalize(address string) string {
host, port, err := net.SplitHostPort(address)
if err != nil {
host = address
port = "22"
}
entry := host
if port != "22" {
entry = "[" + entry + "]:" + port
} else if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
entry = "[" + entry + "]"
}
return entry
}
// Line returns a line to add append to the known_hosts files.
func Line(addresses []string, key ssh.PublicKey) string {
var trimmed []string
for _, a := range addresses {
trimmed = append(trimmed, Normalize(a))
}
return strings.Join(trimmed, ",") + " " + serialize(key)
}
// HashHostname hashes the given hostname. The hostname is not
// normalized before hashing.
func HashHostname(hostname string) string {
// TODO(hanwen): check if we can safely normalize this always.
salt := make([]byte, sha1.Size)
_, err := rand.Read(salt)
if err != nil {
panic(fmt.Sprintf("crypto/rand failure %v", err))
}
hash := hashHost(hostname, salt)
return encodeHash(sha1HashType, salt, hash)
}
func decodeHash(encoded string) (hashType string, salt, hash []byte, err error) {
if len(encoded) == 0 || encoded[0] != '|' {
err = errors.New("knownhosts: hashed host must start with '|'")
return
}
components := strings.Split(encoded, "|")
if len(components) != 4 {
err = fmt.Errorf("knownhosts: got %d components, want 3", len(components))
return
}
hashType = components[1]
if salt, err = base64.StdEncoding.DecodeString(components[2]); err != nil {
return
}
if hash, err = base64.StdEncoding.DecodeString(components[3]); err != nil {
return
}
return
}
func encodeHash(typ string, salt []byte, hash []byte) string {
return strings.Join([]string{"",
typ,
base64.StdEncoding.EncodeToString(salt),
base64.StdEncoding.EncodeToString(hash),
}, "|")
}
// See https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/hostfile.c#120
func hashHost(hostname string, salt []byte) []byte {
mac := hmac.New(sha1.New, salt)
mac.Write([]byte(hostname))
return mac.Sum(nil)
}
type hashedHost struct {
salt []byte
hash []byte
}
const sha1HashType = "1"
func newHashedHost(encoded string) (*hashedHost, error) {
typ, salt, hash, err := decodeHash(encoded)
if err != nil {
return nil, err
}
// The type field seems for future algorithm agility, but it's
// actually hardcoded in openssh currently, see
// https://android.googlesource.com/platform/external/openssh/+/ab28f5495c85297e7a597c1ba62e996416da7c7e/hostfile.c#120
if typ != sha1HashType {
return nil, fmt.Errorf("knownhosts: got hash type %s, must be '1'", typ)
}
return &hashedHost{salt: salt, hash: hash}, nil
}
func (h *hashedHost) match(a addr) bool {
return bytes.Equal(hashHost(Normalize(a.String()), h.salt), h.hash)
}

68
pkg/proto/ssh/mac.go
View File

@ -1,68 +0,0 @@
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Message authentication support
import (
"crypto/hmac"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"hash"
)
type macMode struct {
keySize int
etm bool
new func(key []byte) hash.Hash
}
// truncatingMAC wraps around a hash.Hash and truncates the output digest to
// a given size.
type truncatingMAC struct {
length int
hmac hash.Hash
}
func (t truncatingMAC) Write(data []byte) (int, error) {
return t.hmac.Write(data)
}
func (t truncatingMAC) Sum(in []byte) []byte {
out := t.hmac.Sum(in)
return out[:len(in)+t.length]
}
func (t truncatingMAC) Reset() {
t.hmac.Reset()
}
func (t truncatingMAC) Size() int {
return t.length
}
func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
var macModes = map[string]*macMode{
"hmac-sha2-512-etm@openssh.com": {64, true, func(key []byte) hash.Hash {
return hmac.New(sha512.New, key)
}},
"hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}},
"hmac-sha2-512": {64, false, func(key []byte) hash.Hash {
return hmac.New(sha512.New, key)
}},
"hmac-sha2-256": {32, false, func(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}},
"hmac-sha1": {20, false, func(key []byte) hash.Hash {
return hmac.New(sha1.New, key)
}},
"hmac-sha1-96": {20, false, func(key []byte) hash.Hash {
return truncatingMAC{12, hmac.New(sha1.New, key)}
}},
}

891
pkg/proto/ssh/messages.go
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@ -1,891 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"reflect"
"strconv"
"strings"
)
// These are SSH message type numbers. They are scattered around several
// documents but many were taken from [SSH-PARAMETERS].
const (
msgIgnore = 2
msgUnimplemented = 3
msgDebug = 4
msgNewKeys = 21
)
// SSH messages:
//
// These structures mirror the wire format of the corresponding SSH messages.
// They are marshaled using reflection with the marshal and unmarshal functions
// in this file. The only wrinkle is that a final member of type []byte with a
// ssh tag of "rest" receives the remainder of a packet when unmarshaling.
// See RFC 4253, section 11.1.
const msgDisconnect = 1
// disconnectMsg is the message that signals a disconnect. It is also
// the error type returned from mux.Wait()
type disconnectMsg struct {
Reason uint32 `sshtype:"1"`
Message string
Language string
}
func (d *disconnectMsg) Error() string {
return fmt.Sprintf("ssh: disconnect, reason %d: %s", d.Reason, d.Message)
}
// See RFC 4253, section 7.1.
const msgKexInit = 20
type kexInitMsg struct {
Cookie [16]byte `sshtype:"20"`
KexAlgos []string
ServerHostKeyAlgos []string
CiphersClientServer []string
CiphersServerClient []string
MACsClientServer []string
MACsServerClient []string
CompressionClientServer []string
CompressionServerClient []string
LanguagesClientServer []string
LanguagesServerClient []string
FirstKexFollows bool
Reserved uint32
}
// See RFC 4253, section 8.
// Diffie-Hellman
const msgKexDHInit = 30
type kexDHInitMsg struct {
X *big.Int `sshtype:"30"`
}
const msgKexECDHInit = 30
type kexECDHInitMsg struct {
ClientPubKey []byte `sshtype:"30"`
}
const msgKexECDHReply = 31
type kexECDHReplyMsg struct {
HostKey []byte `sshtype:"31"`
EphemeralPubKey []byte
Signature []byte
}
const msgKexDHReply = 31
type kexDHReplyMsg struct {
HostKey []byte `sshtype:"31"`
Y *big.Int
Signature []byte
}
// See RFC 4419, section 5.
const msgKexDHGexGroup = 31
type kexDHGexGroupMsg struct {
P *big.Int `sshtype:"31"`
G *big.Int
}
const msgKexDHGexInit = 32
type kexDHGexInitMsg struct {
X *big.Int `sshtype:"32"`
}
const msgKexDHGexReply = 33
type kexDHGexReplyMsg struct {
HostKey []byte `sshtype:"33"`
Y *big.Int
Signature []byte
}
const msgKexDHGexRequest = 34
type kexDHGexRequestMsg struct {
MinBits uint32 `sshtype:"34"`
PreferedBits uint32
MaxBits uint32
}
// See RFC 4253, section 10.
const msgServiceRequest = 5
type serviceRequestMsg struct {
Service string `sshtype:"5"`
}
// See RFC 4253, section 10.
const msgServiceAccept = 6
type serviceAcceptMsg struct {
Service string `sshtype:"6"`
}
// See RFC 8308, section 2.3
const msgExtInfo = 7
type extInfoMsg struct {
NumExtensions uint32 `sshtype:"7"`
Payload []byte `ssh:"rest"`
}
// See RFC 4252, section 5.
const msgUserAuthRequest = 50
type userAuthRequestMsg struct {
User string `sshtype:"50"`
Service string
Method string
Payload []byte `ssh:"rest"`
}
// Used for debug printouts of packets.
type userAuthSuccessMsg struct {
}
// See RFC 4252, section 5.1
const msgUserAuthFailure = 51
type userAuthFailureMsg struct {
Methods []string `sshtype:"51"`
PartialSuccess bool
}
// See RFC 4252, section 5.1
const msgUserAuthSuccess = 52
// See RFC 4252, section 5.4
const msgUserAuthBanner = 53
type userAuthBannerMsg struct {
Message string `sshtype:"53"`
// unused, but required to allow message parsing
Language string
}
// See RFC 4256, section 3.2
const msgUserAuthInfoRequest = 60
const msgUserAuthInfoResponse = 61
type userAuthInfoRequestMsg struct {
Name string `sshtype:"60"`
Instruction string
Language string
NumPrompts uint32
Prompts []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
const msgChannelOpen = 90
type channelOpenMsg struct {
ChanType string `sshtype:"90"`
PeersID uint32
PeersWindow uint32
MaxPacketSize uint32
TypeSpecificData []byte `ssh:"rest"`
}
const msgChannelExtendedData = 95
const msgChannelData = 94
// Used for debug print outs of packets.
type channelDataMsg struct {
PeersID uint32 `sshtype:"94"`
Length uint32
Rest []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
const msgChannelOpenConfirm = 91
type channelOpenConfirmMsg struct {
PeersID uint32 `sshtype:"91"`
MyID uint32
MyWindow uint32
MaxPacketSize uint32
TypeSpecificData []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
const msgChannelOpenFailure = 92
type channelOpenFailureMsg struct {
PeersID uint32 `sshtype:"92"`
Reason RejectionReason
Message string
Language string
}
const msgChannelRequest = 98
type channelRequestMsg struct {
PeersID uint32 `sshtype:"98"`
Request string
WantReply bool
RequestSpecificData []byte `ssh:"rest"`
}
// See RFC 4254, section 5.4.
const msgChannelSuccess = 99
type channelRequestSuccessMsg struct {
PeersID uint32 `sshtype:"99"`
}
// See RFC 4254, section 5.4.
const msgChannelFailure = 100
type channelRequestFailureMsg struct {
PeersID uint32 `sshtype:"100"`
}
// See RFC 4254, section 5.3
const msgChannelClose = 97
type channelCloseMsg struct {
PeersID uint32 `sshtype:"97"`
}
// See RFC 4254, section 5.3
const msgChannelEOF = 96
type channelEOFMsg struct {
PeersID uint32 `sshtype:"96"`
}
// See RFC 4254, section 4
const msgGlobalRequest = 80
type globalRequestMsg struct {
Type string `sshtype:"80"`
WantReply bool
Data []byte `ssh:"rest"`
}
// See RFC 4254, section 4
const msgRequestSuccess = 81
type globalRequestSuccessMsg struct {
Data []byte `ssh:"rest" sshtype:"81"`
}
// See RFC 4254, section 4
const msgRequestFailure = 82
type globalRequestFailureMsg struct {
Data []byte `ssh:"rest" sshtype:"82"`
}
// See RFC 4254, section 5.2
const msgChannelWindowAdjust = 93
type windowAdjustMsg struct {
PeersID uint32 `sshtype:"93"`
AdditionalBytes uint32
}
// See RFC 4252, section 7
const msgUserAuthPubKeyOk = 60
type userAuthPubKeyOkMsg struct {
Algo string `sshtype:"60"`
PubKey []byte
}
// See RFC 4462, section 3
const msgUserAuthGSSAPIResponse = 60
type userAuthGSSAPIResponse struct {
SupportMech []byte `sshtype:"60"`
}
const msgUserAuthGSSAPIToken = 61
type userAuthGSSAPIToken struct {
Token []byte `sshtype:"61"`
}
const msgUserAuthGSSAPIMIC = 66
type userAuthGSSAPIMIC struct {
MIC []byte `sshtype:"66"`
}
// See RFC 4462, section 3.9
const msgUserAuthGSSAPIErrTok = 64
type userAuthGSSAPIErrTok struct {
ErrorToken []byte `sshtype:"64"`
}
// See RFC 4462, section 3.8
const msgUserAuthGSSAPIError = 65
type userAuthGSSAPIError struct {
MajorStatus uint32 `sshtype:"65"`
MinorStatus uint32
Message string
LanguageTag string
}
// Transport layer OpenSSH extension. See [PROTOCOL], section 1.9
const msgPing = 192
type pingMsg struct {
Data string `sshtype:"192"`
}
// Transport layer OpenSSH extension. See [PROTOCOL], section 1.9
const msgPong = 193
type pongMsg struct {
Data string `sshtype:"193"`
}
// typeTags returns the possible type bytes for the given reflect.Type, which
// should be a struct. The possible values are separated by a '|' character.
func typeTags(structType reflect.Type) (tags []byte) {
tagStr := structType.Field(0).Tag.Get("sshtype")
for _, tag := range strings.Split(tagStr, "|") {
i, err := strconv.Atoi(tag)
if err == nil {
tags = append(tags, byte(i))
}
}
return tags
}
func fieldError(t reflect.Type, field int, problem string) error {
if problem != "" {
problem = ": " + problem
}
return fmt.Errorf("ssh: unmarshal error for field %s of type %s%s", t.Field(field).Name, t.Name(), problem)
}
var errShortRead = errors.New("ssh: short read")
// Unmarshal parses data in SSH wire format into a structure. The out
// argument should be a pointer to struct. If the first member of the
// struct has the "sshtype" tag set to a '|'-separated set of numbers
// in decimal, the packet must start with one of those numbers. In
// case of error, Unmarshal returns a ParseError or
// UnexpectedMessageError.
func Unmarshal(data []byte, out interface{}) error {
v := reflect.ValueOf(out).Elem()
structType := v.Type()
expectedTypes := typeTags(structType)
var expectedType byte
if len(expectedTypes) > 0 {
expectedType = expectedTypes[0]
}
if len(data) == 0 {
return parseError(expectedType)
}
if len(expectedTypes) > 0 {
goodType := false
for _, e := range expectedTypes {
if e > 0 && data[0] == e {
goodType = true
break
}
}
if !goodType {
return fmt.Errorf("ssh: unexpected message type %d (expected one of %v)", data[0], expectedTypes)
}
data = data[1:]
}
var ok bool
for i := 0; i < v.NumField(); i++ {
field := v.Field(i)
t := field.Type()
switch t.Kind() {
case reflect.Bool:
if len(data) < 1 {
return errShortRead
}
field.SetBool(data[0] != 0)
data = data[1:]
case reflect.Array:
if t.Elem().Kind() != reflect.Uint8 {
return fieldError(structType, i, "array of unsupported type")
}
if len(data) < t.Len() {
return errShortRead
}
for j, n := 0, t.Len(); j < n; j++ {
field.Index(j).Set(reflect.ValueOf(data[j]))
}
data = data[t.Len():]
case reflect.Uint64:
var u64 uint64
if u64, data, ok = parseUint64(data); !ok {
return errShortRead
}
field.SetUint(u64)
case reflect.Uint32:
var u32 uint32
if u32, data, ok = parseUint32(data); !ok {
return errShortRead
}
field.SetUint(uint64(u32))
case reflect.Uint8:
if len(data) < 1 {
return errShortRead
}
field.SetUint(uint64(data[0]))
data = data[1:]
case reflect.String:
var s []byte
if s, data, ok = parseString(data); !ok {
return fieldError(structType, i, "")
}
field.SetString(string(s))
case reflect.Slice:
switch t.Elem().Kind() {
case reflect.Uint8:
if structType.Field(i).Tag.Get("ssh") == "rest" {
field.Set(reflect.ValueOf(data))
data = nil
} else {
var s []byte
if s, data, ok = parseString(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(s))
}
case reflect.String:
var nl []string
if nl, data, ok = parseNameList(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(nl))
default:
return fieldError(structType, i, "slice of unsupported type")
}
case reflect.Ptr:
if t == bigIntType {
var n *big.Int
if n, data, ok = parseInt(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(n))
} else {
return fieldError(structType, i, "pointer to unsupported type")
}
default:
return fieldError(structType, i, fmt.Sprintf("unsupported type: %v", t))
}
}
if len(data) != 0 {
return parseError(expectedType)
}
return nil
}
// Marshal serializes the message in msg to SSH wire format. The msg
// argument should be a struct or pointer to struct. If the first
// member has the "sshtype" tag set to a number in decimal, that
// number is prepended to the result. If the last of member has the
// "ssh" tag set to "rest", its contents are appended to the output.
func Marshal(msg interface{}) []byte {
out := make([]byte, 0, 64)
return marshalStruct(out, msg)
}
func marshalStruct(out []byte, msg interface{}) []byte {
v := reflect.Indirect(reflect.ValueOf(msg))
msgTypes := typeTags(v.Type())
if len(msgTypes) > 0 {
out = append(out, msgTypes[0])
}
for i, n := 0, v.NumField(); i < n; i++ {
field := v.Field(i)
switch t := field.Type(); t.Kind() {
case reflect.Bool:
var v uint8
if field.Bool() {
v = 1
}
out = append(out, v)
case reflect.Array:
if t.Elem().Kind() != reflect.Uint8 {
panic(fmt.Sprintf("array of non-uint8 in field %d: %T", i, field.Interface()))
}
for j, l := 0, t.Len(); j < l; j++ {
out = append(out, uint8(field.Index(j).Uint()))
}
case reflect.Uint32:
out = appendU32(out, uint32(field.Uint()))
case reflect.Uint64:
out = appendU64(out, uint64(field.Uint()))
case reflect.Uint8:
out = append(out, uint8(field.Uint()))
case reflect.String:
s := field.String()
out = appendInt(out, len(s))
out = append(out, s...)
case reflect.Slice:
switch t.Elem().Kind() {
case reflect.Uint8:
if v.Type().Field(i).Tag.Get("ssh") != "rest" {
out = appendInt(out, field.Len())
}
out = append(out, field.Bytes()...)
case reflect.String:
offset := len(out)
out = appendU32(out, 0)
if n := field.Len(); n > 0 {
for j := 0; j < n; j++ {
f := field.Index(j)
if j != 0 {
out = append(out, ',')
}
out = append(out, f.String()...)
}
// overwrite length value
binary.BigEndian.PutUint32(out[offset:], uint32(len(out)-offset-4))
}
default:
panic(fmt.Sprintf("slice of unknown type in field %d: %T", i, field.Interface()))
}
case reflect.Ptr:
if t == bigIntType {
var n *big.Int
nValue := reflect.ValueOf(&n)
nValue.Elem().Set(field)
needed := intLength(n)
oldLength := len(out)
if cap(out)-len(out) < needed {
newOut := make([]byte, len(out), 2*(len(out)+needed))
copy(newOut, out)
out = newOut
}
out = out[:oldLength+needed]
marshalInt(out[oldLength:], n)
} else {
panic(fmt.Sprintf("pointer to unknown type in field %d: %T", i, field.Interface()))
}
}
}
return out
}
var bigOne = big.NewInt(1)
func parseString(in []byte) (out, rest []byte, ok bool) {
if len(in) < 4 {
return
}
length := binary.BigEndian.Uint32(in)
in = in[4:]
if uint32(len(in)) < length {
return
}
out = in[:length]
rest = in[length:]
ok = true
return
}
var (
comma = []byte{','}
emptyNameList = []string{}
)
func parseNameList(in []byte) (out []string, rest []byte, ok bool) {
contents, rest, ok := parseString(in)
if !ok {
return
}
if len(contents) == 0 {
out = emptyNameList
return
}
parts := bytes.Split(contents, comma)
out = make([]string, len(parts))
for i, part := range parts {
out[i] = string(part)
}
return
}
func parseInt(in []byte) (out *big.Int, rest []byte, ok bool) {
contents, rest, ok := parseString(in)
if !ok {
return
}
out = new(big.Int)
if len(contents) > 0 && contents[0]&0x80 == 0x80 {
// This is a negative number
notBytes := make([]byte, len(contents))
for i := range notBytes {
notBytes[i] = ^contents[i]
}
out.SetBytes(notBytes)
out.Add(out, bigOne)
out.Neg(out)
} else {
// Positive number
out.SetBytes(contents)
}
ok = true
return
}
func parseUint32(in []byte) (uint32, []byte, bool) {
if len(in) < 4 {
return 0, nil, false
}
return binary.BigEndian.Uint32(in), in[4:], true
}
func parseUint64(in []byte) (uint64, []byte, bool) {
if len(in) < 8 {
return 0, nil, false
}
return binary.BigEndian.Uint64(in), in[8:], true
}
func intLength(n *big.Int) int {
length := 4 /* length bytes */
if n.Sign() < 0 {
nMinus1 := new(big.Int).Neg(n)
nMinus1.Sub(nMinus1, bigOne)
bitLen := nMinus1.BitLen()
if bitLen%8 == 0 {
// The number will need 0xff padding
length++
}
length += (bitLen + 7) / 8
} else if n.Sign() == 0 {
// A zero is the zero length string
} else {
bitLen := n.BitLen()
if bitLen%8 == 0 {
// The number will need 0x00 padding
length++
}
length += (bitLen + 7) / 8
}
return length
}
func marshalUint32(to []byte, n uint32) []byte {
binary.BigEndian.PutUint32(to, n)
return to[4:]
}
func marshalUint64(to []byte, n uint64) []byte {
binary.BigEndian.PutUint64(to, n)
return to[8:]
}
func marshalInt(to []byte, n *big.Int) []byte {
lengthBytes := to
to = to[4:]
length := 0
if n.Sign() < 0 {
// A negative number has to be converted to two's-complement
// form. So we'll subtract 1 and invert. If the
// most-significant-bit isn't set then we'll need to pad the
// beginning with 0xff in order to keep the number negative.
nMinus1 := new(big.Int).Neg(n)
nMinus1.Sub(nMinus1, bigOne)
bytes := nMinus1.Bytes()
for i := range bytes {
bytes[i] ^= 0xff
}
if len(bytes) == 0 || bytes[0]&0x80 == 0 {
to[0] = 0xff
to = to[1:]
length++
}
nBytes := copy(to, bytes)
to = to[nBytes:]
length += nBytes
} else if n.Sign() == 0 {
// A zero is the zero length string
} else {
bytes := n.Bytes()
if len(bytes) > 0 && bytes[0]&0x80 != 0 {
// We'll have to pad this with a 0x00 in order to
// stop it looking like a negative number.
to[0] = 0
to = to[1:]
length++
}
nBytes := copy(to, bytes)
to = to[nBytes:]
length += nBytes
}
lengthBytes[0] = byte(length >> 24)
lengthBytes[1] = byte(length >> 16)
lengthBytes[2] = byte(length >> 8)
lengthBytes[3] = byte(length)
return to
}
func writeInt(w io.Writer, n *big.Int) {
length := intLength(n)
buf := make([]byte, length)
marshalInt(buf, n)
w.Write(buf)
}
func writeString(w io.Writer, s []byte) {
var lengthBytes [4]byte
lengthBytes[0] = byte(len(s) >> 24)
lengthBytes[1] = byte(len(s) >> 16)
lengthBytes[2] = byte(len(s) >> 8)
lengthBytes[3] = byte(len(s))
w.Write(lengthBytes[:])
w.Write(s)
}
func stringLength(n int) int {
return 4 + n
}
func marshalString(to []byte, s []byte) []byte {
to[0] = byte(len(s) >> 24)
to[1] = byte(len(s) >> 16)
to[2] = byte(len(s) >> 8)
to[3] = byte(len(s))
to = to[4:]
copy(to, s)
return to[len(s):]
}
var bigIntType = reflect.TypeOf((*big.Int)(nil))
// Decode a packet into its corresponding message.
func decode(packet []byte) (interface{}, error) {
var msg interface{}
switch packet[0] {
case msgDisconnect:
msg = new(disconnectMsg)
case msgServiceRequest:
msg = new(serviceRequestMsg)
case msgServiceAccept:
msg = new(serviceAcceptMsg)
case msgExtInfo:
msg = new(extInfoMsg)
case msgKexInit:
msg = new(kexInitMsg)
case msgKexDHInit:
msg = new(kexDHInitMsg)
case msgKexDHReply:
msg = new(kexDHReplyMsg)
case msgUserAuthRequest:
msg = new(userAuthRequestMsg)
case msgUserAuthSuccess:
return new(userAuthSuccessMsg), nil
case msgUserAuthFailure:
msg = new(userAuthFailureMsg)
case msgUserAuthPubKeyOk:
msg = new(userAuthPubKeyOkMsg)
case msgGlobalRequest:
msg = new(globalRequestMsg)
case msgRequestSuccess:
msg = new(globalRequestSuccessMsg)
case msgRequestFailure:
msg = new(globalRequestFailureMsg)
case msgChannelOpen:
msg = new(channelOpenMsg)
case msgChannelData:
msg = new(channelDataMsg)
case msgChannelOpenConfirm:
msg = new(channelOpenConfirmMsg)
case msgChannelOpenFailure:
msg = new(channelOpenFailureMsg)
case msgChannelWindowAdjust:
msg = new(windowAdjustMsg)
case msgChannelEOF:
msg = new(channelEOFMsg)
case msgChannelClose:
msg = new(channelCloseMsg)
case msgChannelRequest:
msg = new(channelRequestMsg)
case msgChannelSuccess:
msg = new(channelRequestSuccessMsg)
case msgChannelFailure:
msg = new(channelRequestFailureMsg)
case msgUserAuthGSSAPIToken:
msg = new(userAuthGSSAPIToken)
case msgUserAuthGSSAPIMIC:
msg = new(userAuthGSSAPIMIC)
case msgUserAuthGSSAPIErrTok:
msg = new(userAuthGSSAPIErrTok)
case msgUserAuthGSSAPIError:
msg = new(userAuthGSSAPIError)
default:
return nil, unexpectedMessageError(0, packet[0])
}
if err := Unmarshal(packet, msg); err != nil {
return nil, err
}
return msg, nil
}
var packetTypeNames = map[byte]string{
msgDisconnect: "disconnectMsg",
msgServiceRequest: "serviceRequestMsg",
msgServiceAccept: "serviceAcceptMsg",
msgExtInfo: "extInfoMsg",
msgKexInit: "kexInitMsg",
msgKexDHInit: "kexDHInitMsg",
msgKexDHReply: "kexDHReplyMsg",
msgUserAuthRequest: "userAuthRequestMsg",
msgUserAuthSuccess: "userAuthSuccessMsg",
msgUserAuthFailure: "userAuthFailureMsg",
msgUserAuthPubKeyOk: "userAuthPubKeyOkMsg",
msgGlobalRequest: "globalRequestMsg",
msgRequestSuccess: "globalRequestSuccessMsg",
msgRequestFailure: "globalRequestFailureMsg",
msgChannelOpen: "channelOpenMsg",
msgChannelData: "channelDataMsg",
msgChannelOpenConfirm: "channelOpenConfirmMsg",
msgChannelOpenFailure: "channelOpenFailureMsg",
msgChannelWindowAdjust: "windowAdjustMsg",
msgChannelEOF: "channelEOFMsg",
msgChannelClose: "channelCloseMsg",
msgChannelRequest: "channelRequestMsg",
msgChannelSuccess: "channelRequestSuccessMsg",
msgChannelFailure: "channelRequestFailureMsg",
}

357
pkg/proto/ssh/mux.go
View File

@ -1,357 +0,0 @@
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"encoding/binary"
"fmt"
"io"
"log"
"sync"
"sync/atomic"
)
// debugMux, if set, causes messages in the connection protocol to be
// logged.
const debugMux = false
// chanList is a thread safe channel list.
type chanList struct {
// protects concurrent access to chans
sync.Mutex
// chans are indexed by the local id of the channel, which the
// other side should send in the PeersId field.
chans []*channel
// This is a debugging aid: it offsets all IDs by this
// amount. This helps distinguish otherwise identical
// server/client muxes
offset uint32
}
// Assigns a channel ID to the given channel.
func (c *chanList) add(ch *channel) uint32 {
c.Lock()
defer c.Unlock()
for i := range c.chans {
if c.chans[i] == nil {
c.chans[i] = ch
return uint32(i) + c.offset
}
}
c.chans = append(c.chans, ch)
return uint32(len(c.chans)-1) + c.offset
}
// getChan returns the channel for the given ID.
func (c *chanList) getChan(id uint32) *channel {
id -= c.offset
c.Lock()
defer c.Unlock()
if id < uint32(len(c.chans)) {
return c.chans[id]
}
return nil
}
func (c *chanList) remove(id uint32) {
id -= c.offset
c.Lock()
if id < uint32(len(c.chans)) {
c.chans[id] = nil
}
c.Unlock()
}
// dropAll forgets all channels it knows, returning them in a slice.
func (c *chanList) dropAll() []*channel {
c.Lock()
defer c.Unlock()
var r []*channel
for _, ch := range c.chans {
if ch == nil {
continue
}
r = append(r, ch)
}
c.chans = nil
return r
}
// mux represents the state for the SSH connection protocol, which
// multiplexes many channels onto a single packet transport.
type mux struct {
conn packetConn
chanList chanList
incomingChannels chan NewChannel
globalSentMu sync.Mutex
globalResponses chan interface{}
incomingRequests chan *Request
errCond *sync.Cond
err error
}
// When debugging, each new chanList instantiation has a different
// offset.
var globalOff uint32
func (m *mux) Wait() error {
m.errCond.L.Lock()
defer m.errCond.L.Unlock()
for m.err == nil {
m.errCond.Wait()
}
return m.err
}
// newMux returns a mux that runs over the given connection.
func newMux(p packetConn) *mux {
m := &mux{
conn: p,
incomingChannels: make(chan NewChannel, chanSize),
globalResponses: make(chan interface{}, 1),
incomingRequests: make(chan *Request, chanSize),
errCond: newCond(),
}
if debugMux {
m.chanList.offset = atomic.AddUint32(&globalOff, 1)
}
go m.loop()
return m
}
func (m *mux) sendMessage(msg interface{}) error {
p := Marshal(msg)
if debugMux {
log.Printf("send global(%d): %#v", m.chanList.offset, msg)
}
return m.conn.writePacket(p)
}
func (m *mux) SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) {
if wantReply {
m.globalSentMu.Lock()
defer m.globalSentMu.Unlock()
}
if err := m.sendMessage(globalRequestMsg{
Type: name,
WantReply: wantReply,
Data: payload,
}); err != nil {
return false, nil, err
}
if !wantReply {
return false, nil, nil
}
msg, ok := <-m.globalResponses
if !ok {
return false, nil, io.EOF
}
switch msg := msg.(type) {
case *globalRequestFailureMsg:
return false, msg.Data, nil
case *globalRequestSuccessMsg:
return true, msg.Data, nil
default:
return false, nil, fmt.Errorf("ssh: unexpected response to request: %#v", msg)
}
}
// ackRequest must be called after processing a global request that
// has WantReply set.
func (m *mux) ackRequest(ok bool, data []byte) error {
if ok {
return m.sendMessage(globalRequestSuccessMsg{Data: data})
}
return m.sendMessage(globalRequestFailureMsg{Data: data})
}
func (m *mux) Close() error {
return m.conn.Close()
}
// loop runs the connection machine. It will process packets until an
// error is encountered. To synchronize on loop exit, use mux.Wait.
func (m *mux) loop() {
var err error
for err == nil {
err = m.onePacket()
}
for _, ch := range m.chanList.dropAll() {
ch.close()
}
close(m.incomingChannels)
close(m.incomingRequests)
close(m.globalResponses)
m.conn.Close()
m.errCond.L.Lock()
m.err = err
m.errCond.Broadcast()
m.errCond.L.Unlock()
if debugMux {
log.Println("loop exit", err)
}
}
// onePacket reads and processes one packet.
func (m *mux) onePacket() error {
packet, err := m.conn.readPacket()
if err != nil {
return err
}
if debugMux {
if packet[0] == msgChannelData || packet[0] == msgChannelExtendedData {
log.Printf("decoding(%d): data packet - %d bytes", m.chanList.offset, len(packet))
} else {
p, _ := decode(packet)
log.Printf("decoding(%d): %d %#v - %d bytes", m.chanList.offset, packet[0], p, len(packet))
}
}
switch packet[0] {
case msgChannelOpen:
return m.handleChannelOpen(packet)
case msgGlobalRequest, msgRequestSuccess, msgRequestFailure:
return m.handleGlobalPacket(packet)
case msgPing:
var msg pingMsg
if err := Unmarshal(packet, &msg); err != nil {
return fmt.Errorf("failed to unmarshal ping@openssh.com message: %w", err)
}
return m.sendMessage(pongMsg(msg))
}
// assume a channel packet.
if len(packet) < 5 {
return parseError(packet[0])
}
id := binary.BigEndian.Uint32(packet[1:])
ch := m.chanList.getChan(id)
if ch == nil {
return m.handleUnknownChannelPacket(id, packet)
}
return ch.handlePacket(packet)
}
func (m *mux) handleGlobalPacket(packet []byte) error {
msg, err := decode(packet)
if err != nil {
return err
}
switch msg := msg.(type) {
case *globalRequestMsg:
m.incomingRequests <- &Request{
Type: msg.Type,
WantReply: msg.WantReply,
Payload: msg.Data,
mux: m,
}
case *globalRequestSuccessMsg, *globalRequestFailureMsg:
m.globalResponses <- msg
default:
panic(fmt.Sprintf("not a global message %#v", msg))
}
return nil
}
// handleChannelOpen schedules a channel to be Accept()ed.
func (m *mux) handleChannelOpen(packet []byte) error {
var msg channelOpenMsg
if err := Unmarshal(packet, &msg); err != nil {
return err
}
if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
failMsg := channelOpenFailureMsg{
PeersID: msg.PeersID,
Reason: ConnectionFailed,
Message: "invalid request",
Language: "en_US.UTF-8",
}
return m.sendMessage(failMsg)
}
c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData)
c.remoteId = msg.PeersID
c.maxRemotePayload = msg.MaxPacketSize
c.remoteWin.add(msg.PeersWindow)
m.incomingChannels <- c
return nil
}
func (m *mux) OpenChannel(chanType string, extra []byte) (Channel, <-chan *Request, error) {
ch, err := m.openChannel(chanType, extra)
if err != nil {
return nil, nil, err
}
return ch, ch.incomingRequests, nil
}
func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) {
ch := m.newChannel(chanType, channelOutbound, extra)
ch.maxIncomingPayload = channelMaxPacket
open := channelOpenMsg{
ChanType: chanType,
PeersWindow: ch.myWindow,
MaxPacketSize: ch.maxIncomingPayload,
TypeSpecificData: extra,
PeersID: ch.localId,
}
if err := m.sendMessage(open); err != nil {
return nil, err
}
switch msg := (<-ch.msg).(type) {
case *channelOpenConfirmMsg:
return ch, nil
case *channelOpenFailureMsg:
return nil, &OpenChannelError{msg.Reason, msg.Message}
default:
return nil, fmt.Errorf("ssh: unexpected packet in response to channel open: %T", msg)
}
}
func (m *mux) handleUnknownChannelPacket(id uint32, packet []byte) error {
msg, err := decode(packet)
if err != nil {
return err
}
switch msg := msg.(type) {
// RFC 4254 section 5.4 says unrecognized channel requests should
// receive a failure response.
case *channelRequestMsg:
if msg.WantReply {
return m.sendMessage(channelRequestFailureMsg{
PeersID: msg.PeersID,
})
}
return nil
default:
return fmt.Errorf("ssh: invalid channel %d", id)
}
}

800
pkg/proto/ssh/server.go
View File

@ -1,800 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
"net"
"strings"
)
// The Permissions type holds fine-grained permissions that are
// specific to a user or a specific authentication method for a user.
// The Permissions value for a successful authentication attempt is
// available in ServerConn, so it can be used to pass information from
// the user-authentication phase to the application layer.
type Permissions struct {
// CriticalOptions indicate restrictions to the default
// permissions, and are typically used in conjunction with
// user certificates. The standard for SSH certificates
// defines "force-command" (only allow the given command to
// execute) and "source-address" (only allow connections from
// the given address). The SSH package currently only enforces
// the "source-address" critical option. It is up to server
// implementations to enforce other critical options, such as
// "force-command", by checking them after the SSH handshake
// is successful. In general, SSH servers should reject
// connections that specify critical options that are unknown
// or not supported.
CriticalOptions map[string]string
// Extensions are extra functionality that the server may
// offer on authenticated connections. Lack of support for an
// extension does not preclude authenticating a user. Common
// extensions are "permit-agent-forwarding",
// "permit-X11-forwarding". The Go SSH library currently does
// not act on any extension, and it is up to server
// implementations to honor them. Extensions can be used to
// pass data from the authentication callbacks to the server
// application layer.
Extensions map[string]string
}
type GSSAPIWithMICConfig struct {
// AllowLogin, must be set, is called when gssapi-with-mic
// authentication is selected (RFC 4462 section 3). The srcName is from the
// results of the GSS-API authentication. The format is username@DOMAIN.
// GSSAPI just guarantees to the server who the user is, but not if they can log in, and with what permissions.
// This callback is called after the user identity is established with GSSAPI to decide if the user can login with
// which permissions. If the user is allowed to login, it should return a nil error.
AllowLogin func(conn ConnMetadata, srcName string) (*Permissions, error)
// Server must be set. It's the implementation
// of the GSSAPIServer interface. See GSSAPIServer interface for details.
Server GSSAPIServer
}
// ServerConfig holds server specific configuration data.
type ServerConfig struct {
// Config contains configuration shared between client and server.
Config
// PublicKeyAuthAlgorithms specifies the supported client public key
// authentication algorithms. Note that this should not include certificate
// types since those use the underlying algorithm. This list is sent to the
// client if it supports the server-sig-algs extension. Order is irrelevant.
// If unspecified then a default set of algorithms is used.
PublicKeyAuthAlgorithms []string
hostKeys []Signer
// NoClientAuth is true if clients are allowed to connect without
// authenticating.
// To determine NoClientAuth at runtime, set NoClientAuth to true
// and the optional NoClientAuthCallback to a non-nil value.
NoClientAuth bool
// NoClientAuthCallback, if non-nil, is called when a user
// attempts to authenticate with auth method "none".
// NoClientAuth must also be set to true for this be used, or
// this func is unused.
NoClientAuthCallback func(ConnMetadata) (*Permissions, error)
// MaxAuthTries specifies the maximum number of authentication attempts
// permitted per connection. If set to a negative number, the number of
// attempts are unlimited. If set to zero, the number of attempts are limited
// to 6.
MaxAuthTries int
// PasswordCallback, if non-nil, is called when a user
// attempts to authenticate using a password.
PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error)
// PublicKeyCallback, if non-nil, is called when a client
// offers a public key for authentication. It must return a nil error
// if the given public key can be used to authenticate the
// given user. For example, see CertChecker.Authenticate. A
// call to this function does not guarantee that the key
// offered is in fact used to authenticate. To record any data
// depending on the public key, store it inside a
// Permissions.Extensions entry.
PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// KeyboardInteractiveCallback, if non-nil, is called when
// keyboard-interactive authentication is selected (RFC
// 4256). The client object's Challenge function should be
// used to query the user. The callback may offer multiple
// Challenge rounds. To avoid information leaks, the client
// should be presented a challenge even if the user is
// unknown.
KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error)
// AuthLogCallback, if non-nil, is called to log all authentication
// attempts.
AuthLogCallback func(conn ConnMetadata, method string, err error)
// ServerVersion is the version identification string to announce in
// the public handshake.
// If empty, a reasonable default is used.
// Note that RFC 4253 section 4.2 requires that this string start with
// "SSH-2.0-".
ServerVersion string
// BannerCallback, if present, is called and the return string is sent to
// the client after key exchange completed but before authentication.
BannerCallback func(conn ConnMetadata) string
// GSSAPIWithMICConfig includes gssapi server and callback, which if both non-nil, is used
// when gssapi-with-mic authentication is selected (RFC 4462 section 3).
GSSAPIWithMICConfig *GSSAPIWithMICConfig
}
// AddHostKey adds a private key as a host key. If an existing host
// key exists with the same public key format, it is replaced. Each server
// config must have at least one host key.
func (s *ServerConfig) AddHostKey(key Signer) {
for i, k := range s.hostKeys {
if k.PublicKey().Type() == key.PublicKey().Type() {
s.hostKeys[i] = key
return
}
}
s.hostKeys = append(s.hostKeys, key)
}
// cachedPubKey contains the results of querying whether a public key is
// acceptable for a user.
type cachedPubKey struct {
user string
pubKeyData []byte
result error
perms *Permissions
}
const maxCachedPubKeys = 16
// pubKeyCache caches tests for public keys. Since SSH clients
// will query whether a public key is acceptable before attempting to
// authenticate with it, we end up with duplicate queries for public
// key validity. The cache only applies to a single ServerConn.
type pubKeyCache struct {
keys []cachedPubKey
}
// get returns the result for a given user/algo/key tuple.
func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) {
for _, k := range c.keys {
if k.user == user && bytes.Equal(k.pubKeyData, pubKeyData) {
return k, true
}
}
return cachedPubKey{}, false
}
// add adds the given tuple to the cache.
func (c *pubKeyCache) add(candidate cachedPubKey) {
if len(c.keys) < maxCachedPubKeys {
c.keys = append(c.keys, candidate)
}
}
// ServerConn is an authenticated SSH connection, as seen from the
// server
type ServerConn struct {
Conn
// If the succeeding authentication callback returned a
// non-nil Permissions pointer, it is stored here.
Permissions *Permissions
}
// NewServerConn starts a new SSH server with c as the underlying
// transport. It starts with a handshake and, if the handshake is
// unsuccessful, it closes the connection and returns an error. The
// Request and NewChannel channels must be serviced, or the connection
// will hang.
//
// The returned error may be of type *ServerAuthError for
// authentication errors.
func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) {
fullConf := *config
fullConf.SetDefaults()
if fullConf.MaxAuthTries == 0 {
fullConf.MaxAuthTries = 6
}
if len(fullConf.PublicKeyAuthAlgorithms) == 0 {
fullConf.PublicKeyAuthAlgorithms = supportedPubKeyAuthAlgos
} else {
for _, algo := range fullConf.PublicKeyAuthAlgorithms {
if !contains(supportedPubKeyAuthAlgos, algo) {
return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo)
}
}
}
// Check if the config contains any unsupported key exchanges
for _, kex := range fullConf.KeyExchanges {
if _, ok := serverForbiddenKexAlgos[kex]; ok {
return nil, nil, nil, fmt.Errorf("ssh: unsupported key exchange %s for server", kex)
}
}
s := &connection{
sshConn: sshConn{conn: c},
}
perms, err := s.serverHandshake(&fullConf)
if err != nil {
c.Close()
return nil, nil, nil, err
}
return &ServerConn{s, perms}, s.mux.incomingChannels, s.mux.incomingRequests, nil
}
// signAndMarshal signs the data with the appropriate algorithm,
// and serializes the result in SSH wire format. algo is the negotiate
// algorithm and may be a certificate type.
func signAndMarshal(k AlgorithmSigner, rand io.Reader, data []byte, algo string) ([]byte, error) {
sig, err := k.SignWithAlgorithm(rand, data, underlyingAlgo(algo))
if err != nil {
return nil, err
}
return Marshal(sig), nil
}
// handshake performs key exchange and user authentication.
func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) {
if len(config.hostKeys) == 0 {
return nil, errors.New("ssh: server has no host keys")
}
if !config.NoClientAuth && config.PasswordCallback == nil && config.PublicKeyCallback == nil &&
config.KeyboardInteractiveCallback == nil && (config.GSSAPIWithMICConfig == nil ||
config.GSSAPIWithMICConfig.AllowLogin == nil || config.GSSAPIWithMICConfig.Server == nil) {
return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
}
if config.ServerVersion != "" {
s.serverVersion = []byte(config.ServerVersion)
} else {
s.serverVersion = []byte(packageVersion)
}
var err error
s.clientVersion, err = exchangeVersions(s.sshConn.conn, s.serverVersion)
if err != nil {
return nil, err
}
tr := newTransport(s.sshConn.conn, config.Rand, false /* not client */)
s.transport = newServerTransport(tr, s.clientVersion, s.serverVersion, config)
if err := s.transport.waitSession(); err != nil {
return nil, err
}
// We just did the key change, so the session ID is established.
s.sessionID = s.transport.getSessionID()
var packet []byte
if packet, err = s.transport.readPacket(); err != nil {
return nil, err
}
var serviceRequest serviceRequestMsg
if err = Unmarshal(packet, &serviceRequest); err != nil {
return nil, err
}
if serviceRequest.Service != serviceUserAuth {
return nil, errors.New("ssh: requested service '" + serviceRequest.Service + "' before authenticating")
}
serviceAccept := serviceAcceptMsg{
Service: serviceUserAuth,
}
if err := s.transport.writePacket(Marshal(&serviceAccept)); err != nil {
return nil, err
}
perms, err := s.serverAuthenticate(config)
if err != nil {
return nil, err
}
s.mux = newMux(s.transport)
return perms, err
}
func checkSourceAddress(addr net.Addr, sourceAddrs string) error {
if addr == nil {
return errors.New("ssh: no address known for client, but source-address match required")
}
tcpAddr, ok := addr.(*net.TCPAddr)
if !ok {
return fmt.Errorf("ssh: remote address %v is not an TCP address when checking source-address match", addr)
}
for _, sourceAddr := range strings.Split(sourceAddrs, ",") {
if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil {
if allowedIP.Equal(tcpAddr.IP) {
return nil
}
} else {
_, ipNet, err := net.ParseCIDR(sourceAddr)
if err != nil {
return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err)
}
if ipNet.Contains(tcpAddr.IP) {
return nil
}
}
}
return fmt.Errorf("ssh: remote address %v is not allowed because of source-address restriction", addr)
}
func gssExchangeToken(gssapiConfig *GSSAPIWithMICConfig, token []byte, s *connection,
sessionID []byte, userAuthReq userAuthRequestMsg) (authErr error, perms *Permissions, err error) {
gssAPIServer := gssapiConfig.Server
defer gssAPIServer.DeleteSecContext()
var srcName string
for {
var (
outToken []byte
needContinue bool
)
outToken, srcName, needContinue, err = gssAPIServer.AcceptSecContext(token)
if err != nil {
return err, nil, nil
}
if len(outToken) != 0 {
if err := s.transport.writePacket(Marshal(&userAuthGSSAPIToken{
Token: outToken,
})); err != nil {
return nil, nil, err
}
}
if !needContinue {
break
}
packet, err := s.transport.readPacket()
if err != nil {
return nil, nil, err
}
userAuthGSSAPITokenReq := &userAuthGSSAPIToken{}
if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil {
return nil, nil, err
}
token = userAuthGSSAPITokenReq.Token
}
packet, err := s.transport.readPacket()
if err != nil {
return nil, nil, err
}
userAuthGSSAPIMICReq := &userAuthGSSAPIMIC{}
if err := Unmarshal(packet, userAuthGSSAPIMICReq); err != nil {
return nil, nil, err
}
mic := buildMIC(string(sessionID), userAuthReq.User, userAuthReq.Service, userAuthReq.Method)
if err := gssAPIServer.VerifyMIC(mic, userAuthGSSAPIMICReq.MIC); err != nil {
return err, nil, nil
}
perms, authErr = gssapiConfig.AllowLogin(s, srcName)
return authErr, perms, nil
}
// isAlgoCompatible checks if the signature format is compatible with the
// selected algorithm taking into account edge cases that occur with old
// clients.
func isAlgoCompatible(algo, sigFormat string) bool {
// Compatibility for old clients.
//
// For certificate authentication with OpenSSH 7.2-7.7 signature format can
// be rsa-sha2-256 or rsa-sha2-512 for the algorithm
// ssh-rsa-cert-v01@openssh.com.
//
// With gpg-agent < 2.2.6 the algorithm can be rsa-sha2-256 or rsa-sha2-512
// for signature format ssh-rsa.
if isRSA(algo) && isRSA(sigFormat) {
return true
}
// Standard case: the underlying algorithm must match the signature format.
return underlyingAlgo(algo) == sigFormat
}
// ServerAuthError represents server authentication errors and is
// sometimes returned by NewServerConn. It appends any authentication
// errors that may occur, and is returned if all of the authentication
// methods provided by the user failed to authenticate.
type ServerAuthError struct {
// Errors contains authentication errors returned by the authentication
// callback methods. The first entry is typically ErrNoAuth.
Errors []error
}
func (l ServerAuthError) Error() string {
var errs []string
for _, err := range l.Errors {
errs = append(errs, err.Error())
}
return "[" + strings.Join(errs, ", ") + "]"
}
// ErrNoAuth is the error value returned if no
// authentication method has been passed yet. This happens as a normal
// part of the authentication loop, since the client first tries
// 'none' authentication to discover available methods.
// It is returned in ServerAuthError.Errors from NewServerConn.
var ErrNoAuth = errors.New("ssh: no auth passed yet")
func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) {
sessionID := s.transport.getSessionID()
var cache pubKeyCache
var perms *Permissions
authFailures := 0
var authErrs []error
var displayedBanner bool
userAuthLoop:
for {
if authFailures >= config.MaxAuthTries && config.MaxAuthTries > 0 {
discMsg := &disconnectMsg{
Reason: 2,
Message: "too many authentication failures",
}
if err := s.transport.writePacket(Marshal(discMsg)); err != nil {
return nil, err
}
return nil, discMsg
}
var userAuthReq userAuthRequestMsg
if packet, err := s.transport.readPacket(); err != nil {
if err == io.EOF {
return nil, &ServerAuthError{Errors: authErrs}
}
return nil, err
} else if err = Unmarshal(packet, &userAuthReq); err != nil {
return nil, err
}
if userAuthReq.Service != serviceSSH {
return nil, errors.New("ssh: client attempted to negotiate for unknown service: " + userAuthReq.Service)
}
s.user = userAuthReq.User
if !displayedBanner && config.BannerCallback != nil {
displayedBanner = true
msg := config.BannerCallback(s)
if msg != "" {
bannerMsg := &userAuthBannerMsg{
Message: msg,
}
if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
return nil, err
}
}
}
perms = nil
authErr := ErrNoAuth
switch userAuthReq.Method {
case "none":
if config.NoClientAuth {
if config.NoClientAuthCallback != nil {
perms, authErr = config.NoClientAuthCallback(s)
} else {
authErr = nil
}
}
// allow initial attempt of 'none' without penalty
if authFailures == 0 {
authFailures--
}
case "password":
if config.PasswordCallback == nil {
authErr = errors.New("ssh: password auth not configured")
break
}
payload := userAuthReq.Payload
if len(payload) < 1 || payload[0] != 0 {
return nil, parseError(msgUserAuthRequest)
}
payload = payload[1:]
password, payload, ok := parseString(payload)
if !ok || len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
perms, authErr = config.PasswordCallback(s, password)
case "keyboard-interactive":
if config.KeyboardInteractiveCallback == nil {
authErr = errors.New("ssh: keyboard-interactive auth not configured")
break
}
prompter := &sshClientKeyboardInteractive{s}
perms, authErr = config.KeyboardInteractiveCallback(s, prompter.Challenge)
case "publickey":
if config.PublicKeyCallback == nil {
authErr = errors.New("ssh: publickey auth not configured")
break
}
payload := userAuthReq.Payload
if len(payload) < 1 {
return nil, parseError(msgUserAuthRequest)
}
isQuery := payload[0] == 0
payload = payload[1:]
algoBytes, payload, ok := parseString(payload)
if !ok {
return nil, parseError(msgUserAuthRequest)
}
algo := string(algoBytes)
if !contains(config.PublicKeyAuthAlgorithms, underlyingAlgo(algo)) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo)
break
}
pubKeyData, payload, ok := parseString(payload)
if !ok {
return nil, parseError(msgUserAuthRequest)
}
pubKey, err := ParsePublicKey(pubKeyData)
if err != nil {
return nil, err
}
candidate, ok := cache.get(s.user, pubKeyData)
if !ok {
candidate.user = s.user
candidate.pubKeyData = pubKeyData
candidate.perms, candidate.result = config.PublicKeyCallback(s, pubKey)
if candidate.result == nil && candidate.perms != nil && candidate.perms.CriticalOptions != nil && candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" {
candidate.result = checkSourceAddress(
s.RemoteAddr(),
candidate.perms.CriticalOptions[sourceAddressCriticalOption])
}
cache.add(candidate)
}
if isQuery {
// The client can query if the given public key
// would be okay.
if len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
if candidate.result == nil {
okMsg := userAuthPubKeyOkMsg{
Algo: algo,
PubKey: pubKeyData,
}
if err = s.transport.writePacket(Marshal(&okMsg)); err != nil {
return nil, err
}
continue userAuthLoop
}
authErr = candidate.result
} else {
sig, payload, ok := parseSignature(payload)
if !ok || len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
// Ensure the declared public key algo is compatible with the
// decoded one. This check will ensure we don't accept e.g.
// ssh-rsa-cert-v01@openssh.com algorithm with ssh-rsa public
// key type. The algorithm and public key type must be
// consistent: both must be certificate algorithms, or neither.
if !contains(algorithmsForKeyFormat(pubKey.Type()), algo) {
authErr = fmt.Errorf("ssh: public key type %q not compatible with selected algorithm %q",
pubKey.Type(), algo)
break
}
// Ensure the public key algo and signature algo
// are supported. Compare the private key
// algorithm name that corresponds to algo with
// sig.Format. This is usually the same, but
// for certs, the names differ.
if !contains(config.PublicKeyAuthAlgorithms, sig.Format) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format)
break
}
if !isAlgoCompatible(algo, sig.Format) {
authErr = fmt.Errorf("ssh: signature %q not compatible with selected algorithm %q", sig.Format, algo)
break
}
signedData := buildDataSignedForAuth(sessionID, userAuthReq, algo, pubKeyData)
if err := pubKey.Verify(signedData, sig); err != nil {
return nil, err
}
authErr = candidate.result
perms = candidate.perms
}
case "gssapi-with-mic":
if config.GSSAPIWithMICConfig == nil {
authErr = errors.New("ssh: gssapi-with-mic auth not configured")
break
}
gssapiConfig := config.GSSAPIWithMICConfig
userAuthRequestGSSAPI, err := parseGSSAPIPayload(userAuthReq.Payload)
if err != nil {
return nil, parseError(msgUserAuthRequest)
}
// OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication.
if userAuthRequestGSSAPI.N == 0 {
authErr = fmt.Errorf("ssh: Mechanism negotiation is not supported")
break
}
var i uint32
present := false
for i = 0; i < userAuthRequestGSSAPI.N; i++ {
if userAuthRequestGSSAPI.OIDS[i].Equal(krb5Mesh) {
present = true
break
}
}
if !present {
authErr = fmt.Errorf("ssh: GSSAPI authentication must use the Kerberos V5 mechanism")
break
}
// Initial server response, see RFC 4462 section 3.3.
if err := s.transport.writePacket(Marshal(&userAuthGSSAPIResponse{
SupportMech: krb5OID,
})); err != nil {
return nil, err
}
// Exchange token, see RFC 4462 section 3.4.
packet, err := s.transport.readPacket()
if err != nil {
return nil, err
}
userAuthGSSAPITokenReq := &userAuthGSSAPIToken{}
if err := Unmarshal(packet, userAuthGSSAPITokenReq); err != nil {
return nil, err
}
authErr, perms, err = gssExchangeToken(gssapiConfig, userAuthGSSAPITokenReq.Token, s, sessionID,
userAuthReq)
if err != nil {
return nil, err
}
default:
authErr = fmt.Errorf("ssh: unknown method %q", userAuthReq.Method)
}
authErrs = append(authErrs, authErr)
if config.AuthLogCallback != nil {
config.AuthLogCallback(s, userAuthReq.Method, authErr)
}
if authErr == nil {
break userAuthLoop
}
authFailures++
if config.MaxAuthTries > 0 && authFailures >= config.MaxAuthTries {
// If we have hit the max attempts, don't bother sending the
// final SSH_MSG_USERAUTH_FAILURE message, since there are
// no more authentication methods which can be attempted,
// and this message may cause the client to re-attempt
// authentication while we send the disconnect message.
// Continue, and trigger the disconnect at the start of
// the loop.
//
// The SSH specification is somewhat confusing about this,
// RFC 4252 Section 5.1 requires each authentication failure
// be responded to with a respective SSH_MSG_USERAUTH_FAILURE
// message, but Section 4 says the server should disconnect
// after some number of attempts, but it isn't explicit which
// message should take precedence (i.e. should there be a failure
// message than a disconnect message, or if we are going to
// disconnect, should we only send that message.)
//
// Either way, OpenSSH disconnects immediately after the last
// failed authnetication attempt, and given they are typically
// considered the golden implementation it seems reasonable
// to match that behavior.
continue
}
var failureMsg userAuthFailureMsg
if config.PasswordCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "password")
}
if config.PublicKeyCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "publickey")
}
if config.KeyboardInteractiveCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "keyboard-interactive")
}
if config.GSSAPIWithMICConfig != nil && config.GSSAPIWithMICConfig.Server != nil &&
config.GSSAPIWithMICConfig.AllowLogin != nil {
failureMsg.Methods = append(failureMsg.Methods, "gssapi-with-mic")
}
if len(failureMsg.Methods) == 0 {
return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
}
if err := s.transport.writePacket(Marshal(&failureMsg)); err != nil {
return nil, err
}
}
if err := s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil {
return nil, err
}
return perms, nil
}
// sshClientKeyboardInteractive implements a ClientKeyboardInteractive by
// asking the client on the other side of a ServerConn.
type sshClientKeyboardInteractive struct {
*connection
}
func (c *sshClientKeyboardInteractive) Challenge(name, instruction string, questions []string, echos []bool) (answers []string, err error) {
if len(questions) != len(echos) {
return nil, errors.New("ssh: echos and questions must have equal length")
}
var prompts []byte
for i := range questions {
prompts = appendString(prompts, questions[i])
prompts = appendBool(prompts, echos[i])
}
if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{
Name: name,
Instruction: instruction,
NumPrompts: uint32(len(questions)),
Prompts: prompts,
})); err != nil {
return nil, err
}
packet, err := c.transport.readPacket()
if err != nil {
return nil, err
}
if packet[0] != msgUserAuthInfoResponse {
return nil, unexpectedMessageError(msgUserAuthInfoResponse, packet[0])
}
packet = packet[1:]
n, packet, ok := parseUint32(packet)
if !ok || int(n) != len(questions) {
return nil, parseError(msgUserAuthInfoResponse)
}
for i := uint32(0); i < n; i++ {
ans, rest, ok := parseString(packet)
if !ok {
return nil, parseError(msgUserAuthInfoResponse)
}
answers = append(answers, string(ans))
packet = rest
}
if len(packet) != 0 {
return nil, errors.New("ssh: junk at end of message")
}
return answers, nil
}

647
pkg/proto/ssh/session.go
View File

@ -1,647 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Session implements an interactive session described in
// "RFC 4254, section 6".
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"sync"
)
type Signal string
// POSIX signals as listed in RFC 4254 Section 6.10.
const (
SIGABRT Signal = "ABRT"
SIGALRM Signal = "ALRM"
SIGFPE Signal = "FPE"
SIGHUP Signal = "HUP"
SIGILL Signal = "ILL"
SIGINT Signal = "INT"
SIGKILL Signal = "KILL"
SIGPIPE Signal = "PIPE"
SIGQUIT Signal = "QUIT"
SIGSEGV Signal = "SEGV"
SIGTERM Signal = "TERM"
SIGUSR1 Signal = "USR1"
SIGUSR2 Signal = "USR2"
)
var signals = map[Signal]int{
SIGABRT: 6,
SIGALRM: 14,
SIGFPE: 8,
SIGHUP: 1,
SIGILL: 4,
SIGINT: 2,
SIGKILL: 9,
SIGPIPE: 13,
SIGQUIT: 3,
SIGSEGV: 11,
SIGTERM: 15,
}
type TerminalModes map[uint8]uint32
// POSIX terminal mode flags as listed in RFC 4254 Section 8.
const (
tty_OP_END = 0
VINTR = 1
VQUIT = 2
VERASE = 3
VKILL = 4
VEOF = 5
VEOL = 6
VEOL2 = 7
VSTART = 8
VSTOP = 9
VSUSP = 10
VDSUSP = 11
VREPRINT = 12
VWERASE = 13
VLNEXT = 14
VFLUSH = 15
VSWTCH = 16
VSTATUS = 17
VDISCARD = 18
IGNPAR = 30
PARMRK = 31
INPCK = 32
ISTRIP = 33
INLCR = 34
IGNCR = 35
ICRNL = 36
IUCLC = 37
IXON = 38
IXANY = 39
IXOFF = 40
IMAXBEL = 41
IUTF8 = 42 // RFC 8160
ISIG = 50
ICANON = 51
XCASE = 52
ECHO = 53
ECHOE = 54
ECHOK = 55
ECHONL = 56
NOFLSH = 57
TOSTOP = 58
IEXTEN = 59
ECHOCTL = 60
ECHOKE = 61
PENDIN = 62
OPOST = 70
OLCUC = 71
ONLCR = 72
OCRNL = 73
ONOCR = 74
ONLRET = 75
CS7 = 90
CS8 = 91
PARENB = 92
PARODD = 93
TTY_OP_ISPEED = 128
TTY_OP_OSPEED = 129
)
// A Session represents a connection to a remote command or shell.
type Session struct {
// Stdin specifies the remote process's standard input.
// If Stdin is nil, the remote process reads from an empty
// bytes.Buffer.
Stdin io.Reader
// Stdout and Stderr specify the remote process's standard
// output and error.
//
// If either is nil, Run connects the corresponding file
// descriptor to an instance of io.Discard. There is a
// fixed amount of buffering that is shared for the two streams.
// If either blocks it may eventually cause the remote
// command to block.
Stdout io.Writer
Stderr io.Writer
ch Channel // the channel backing this session
started bool // true once Start, Run or Shell is invoked.
copyFuncs []func() error
errors chan error // one send per copyFunc
// true if pipe method is active
stdinpipe, stdoutpipe, stderrpipe bool
// stdinPipeWriter is non-nil if StdinPipe has not been called
// and Stdin was specified by the user; it is the write end of
// a pipe connecting Session.Stdin to the stdin channel.
stdinPipeWriter io.WriteCloser
exitStatus chan error
}
// SendRequest sends an out-of-band channel request on the SSH channel
// underlying the session.
func (s *Session) SendRequest(name string, wantReply bool, payload []byte) (bool, error) {
return s.ch.SendRequest(name, wantReply, payload)
}
func (s *Session) Close() error {
return s.ch.Close()
}
// RFC 4254 Section 6.4.
type setenvRequest struct {
Name string
Value string
}
// Setenv sets an environment variable that will be applied to any
// command executed by Shell or Run.
func (s *Session) Setenv(name, value string) error {
msg := setenvRequest{
Name: name,
Value: value,
}
ok, err := s.ch.SendRequest("env", true, Marshal(&msg))
if err == nil && !ok {
err = errors.New("ssh: setenv failed")
}
return err
}
// RFC 4254 Section 6.2.
type ptyRequestMsg struct {
Term string
Columns uint32
Rows uint32
Width uint32
Height uint32
Modelist string
}
// RequestPty requests the association of a pty with the session on the remote host.
func (s *Session) RequestPty(term string, h, w int, termmodes TerminalModes) error {
var tm []byte
for k, v := range termmodes {
kv := struct {
Key byte
Val uint32
}{k, v}
tm = append(tm, Marshal(&kv)...)
}
tm = append(tm, tty_OP_END)
req := ptyRequestMsg{
Term: term,
Columns: uint32(w),
Rows: uint32(h),
Width: uint32(w * 8),
Height: uint32(h * 8),
Modelist: string(tm),
}
ok, err := s.ch.SendRequest("pty-req", true, Marshal(&req))
if err == nil && !ok {
err = errors.New("ssh: pty-req failed")
}
return err
}
// RFC 4254 Section 6.5.
type subsystemRequestMsg struct {
Subsystem string
}
// RequestSubsystem requests the association of a subsystem with the session on the remote host.
// A subsystem is a predefined command that runs in the background when the ssh session is initiated
func (s *Session) RequestSubsystem(subsystem string) error {
msg := subsystemRequestMsg{
Subsystem: subsystem,
}
ok, err := s.ch.SendRequest("subsystem", true, Marshal(&msg))
if err == nil && !ok {
err = errors.New("ssh: subsystem request failed")
}
return err
}
// RFC 4254 Section 6.7.
type ptyWindowChangeMsg struct {
Columns uint32
Rows uint32
Width uint32
Height uint32
}
// WindowChange informs the remote host about a terminal window dimension change to h rows and w columns.
func (s *Session) WindowChange(h, w int) error {
req := ptyWindowChangeMsg{
Columns: uint32(w),
Rows: uint32(h),
Width: uint32(w * 8),
Height: uint32(h * 8),
}
_, err := s.ch.SendRequest("window-change", false, Marshal(&req))
return err
}
// RFC 4254 Section 6.9.
type signalMsg struct {
Signal string
}
// Signal sends the given signal to the remote process.
// sig is one of the SIG* constants.
func (s *Session) Signal(sig Signal) error {
msg := signalMsg{
Signal: string(sig),
}
_, err := s.ch.SendRequest("signal", false, Marshal(&msg))
return err
}
// RFC 4254 Section 6.5.
type execMsg struct {
Command string
}
// Start runs cmd on the remote host. Typically, the remote
// server passes cmd to the shell for interpretation.
// A Session only accepts one call to Run, Start or Shell.
func (s *Session) Start(cmd string) error {
if s.started {
return errors.New("ssh: session already started")
}
req := execMsg{
Command: cmd,
}
ok, err := s.ch.SendRequest("exec", true, Marshal(&req))
if err == nil && !ok {
err = fmt.Errorf("ssh: command %v failed", cmd)
}
if err != nil {
return err
}
return s.start()
}
// Run runs cmd on the remote host. Typically, the remote
// server passes cmd to the shell for interpretation.
// A Session only accepts one call to Run, Start, Shell, Output,
// or CombinedOutput.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the remote server does not send an exit status, an error of type
// *ExitMissingError is returned. If the command completes
// unsuccessfully or is interrupted by a signal, the error is of type
// *ExitError. Other error types may be returned for I/O problems.
func (s *Session) Run(cmd string) error {
err := s.Start(cmd)
if err != nil {
return err
}
return s.Wait()
}
// Output runs cmd on the remote host and returns its standard output.
func (s *Session) Output(cmd string) ([]byte, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
var b bytes.Buffer
s.Stdout = &b
err := s.Run(cmd)
return b.Bytes(), err
}
type singleWriter struct {
b bytes.Buffer
mu sync.Mutex
}
func (w *singleWriter) Write(p []byte) (int, error) {
w.mu.Lock()
defer w.mu.Unlock()
return w.b.Write(p)
}
// CombinedOutput runs cmd on the remote host and returns its combined
// standard output and standard error.
func (s *Session) CombinedOutput(cmd string) ([]byte, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
if s.Stderr != nil {
return nil, errors.New("ssh: Stderr already set")
}
var b singleWriter
s.Stdout = &b
s.Stderr = &b
err := s.Run(cmd)
return b.b.Bytes(), err
}
// Shell starts a login shell on the remote host. A Session only
// accepts one call to Run, Start, Shell, Output, or CombinedOutput.
func (s *Session) Shell() error {
if s.started {
return errors.New("ssh: session already started")
}
ok, err := s.ch.SendRequest("shell", true, nil)
if err == nil && !ok {
return errors.New("ssh: could not start shell")
}
if err != nil {
return err
}
return s.start()
}
func (s *Session) start() error {
s.started = true
type F func(*Session)
for _, setupFd := range []F{(*Session).stdin, (*Session).stdout, (*Session).stderr} {
setupFd(s)
}
s.errors = make(chan error, len(s.copyFuncs))
for _, fn := range s.copyFuncs {
go func(fn func() error) {
s.errors <- fn()
}(fn)
}
return nil
}
// Wait waits for the remote command to exit.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the remote server does not send an exit status, an error of type
// *ExitMissingError is returned. If the command completes
// unsuccessfully or is interrupted by a signal, the error is of type
// *ExitError. Other error types may be returned for I/O problems.
func (s *Session) Wait() error {
if !s.started {
return errors.New("ssh: session not started")
}
waitErr := <-s.exitStatus
if s.stdinPipeWriter != nil {
s.stdinPipeWriter.Close()
}
var copyError error
for range s.copyFuncs {
if err := <-s.errors; err != nil && copyError == nil {
copyError = err
}
}
if waitErr != nil {
return waitErr
}
return copyError
}
func (s *Session) wait(reqs <-chan *Request) error {
wm := Waitmsg{status: -1}
// Wait for msg channel to be closed before returning.
for msg := range reqs {
switch msg.Type {
case "exit-status":
wm.status = int(binary.BigEndian.Uint32(msg.Payload))
case "exit-signal":
var sigval struct {
Signal string
CoreDumped bool
Error string
Lang string
}
if err := Unmarshal(msg.Payload, &sigval); err != nil {
return err
}
// Must sanitize strings?
wm.signal = sigval.Signal
wm.msg = sigval.Error
wm.lang = sigval.Lang
default:
// This handles keepalives and matches
// OpenSSH's behaviour.
if msg.WantReply {
msg.Reply(false, nil)
}
}
}
if wm.status == 0 {
return nil
}
if wm.status == -1 {
// exit-status was never sent from server
if wm.signal == "" {
// signal was not sent either. RFC 4254
// section 6.10 recommends against this
// behavior, but it is allowed, so we let
// clients handle it.
return &ExitMissingError{}
}
wm.status = 128
if _, ok := signals[Signal(wm.signal)]; ok {
wm.status += signals[Signal(wm.signal)]
}
}
return &ExitError{wm}
}
// ExitMissingError is returned if a session is torn down cleanly, but
// the server sends no confirmation of the exit status.
type ExitMissingError struct{}
func (e *ExitMissingError) Error() string {
return "wait: remote command exited without exit status or exit signal"
}
func (s *Session) stdin() {
if s.stdinpipe {
return
}
var stdin io.Reader
if s.Stdin == nil {
stdin = new(bytes.Buffer)
} else {
r, w := io.Pipe()
go func() {
_, err := io.Copy(w, s.Stdin)
w.CloseWithError(err)
}()
stdin, s.stdinPipeWriter = r, w
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.ch, stdin)
if err1 := s.ch.CloseWrite(); err == nil && err1 != io.EOF {
err = err1
}
return err
})
}
func (s *Session) stdout() {
if s.stdoutpipe {
return
}
if s.Stdout == nil {
s.Stdout = io.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stdout, s.ch)
return err
})
}
func (s *Session) stderr() {
if s.stderrpipe {
return
}
if s.Stderr == nil {
s.Stderr = io.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stderr, s.ch.Stderr())
return err
})
}
// sessionStdin reroutes Close to CloseWrite.
type sessionStdin struct {
io.Writer
ch Channel
}
func (s *sessionStdin) Close() error {
return s.ch.CloseWrite()
}
// StdinPipe returns a pipe that will be connected to the
// remote command's standard input when the command starts.
func (s *Session) StdinPipe() (io.WriteCloser, error) {
if s.Stdin != nil {
return nil, errors.New("ssh: Stdin already set")
}
if s.started {
return nil, errors.New("ssh: StdinPipe after process started")
}
s.stdinpipe = true
return &sessionStdin{s.ch, s.ch}, nil
}
// StdoutPipe returns a pipe that will be connected to the
// remote command's standard output when the command starts.
// There is a fixed amount of buffering that is shared between
// stdout and stderr streams. If the StdoutPipe reader is
// not serviced fast enough it may eventually cause the
// remote command to block.
func (s *Session) StdoutPipe() (io.Reader, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
if s.started {
return nil, errors.New("ssh: StdoutPipe after process started")
}
s.stdoutpipe = true
return s.ch, nil
}
// StderrPipe returns a pipe that will be connected to the
// remote command's standard error when the command starts.
// There is a fixed amount of buffering that is shared between
// stdout and stderr streams. If the StderrPipe reader is
// not serviced fast enough it may eventually cause the
// remote command to block.
func (s *Session) StderrPipe() (io.Reader, error) {
if s.Stderr != nil {
return nil, errors.New("ssh: Stderr already set")
}
if s.started {
return nil, errors.New("ssh: StderrPipe after process started")
}
s.stderrpipe = true
return s.ch.Stderr(), nil
}
// newSession returns a new interactive session on the remote host.
func newSession(ch Channel, reqs <-chan *Request) (*Session, error) {
s := &Session{
ch: ch,
}
s.exitStatus = make(chan error, 1)
go func() {
s.exitStatus <- s.wait(reqs)
}()
return s, nil
}
// An ExitError reports unsuccessful completion of a remote command.
type ExitError struct {
Waitmsg
}
func (e *ExitError) Error() string {
return e.Waitmsg.String()
}
// Waitmsg stores the information about an exited remote command
// as reported by Wait.
type Waitmsg struct {
status int
signal string
msg string
lang string
}
// ExitStatus returns the exit status of the remote command.
func (w Waitmsg) ExitStatus() int {
return w.status
}
// Signal returns the exit signal of the remote command if
// it was terminated violently.
func (w Waitmsg) Signal() string {
return w.signal
}
// Msg returns the exit message given by the remote command
func (w Waitmsg) Msg() string {
return w.msg
}
// Lang returns the language tag. See RFC 3066
func (w Waitmsg) Lang() string {
return w.lang
}
func (w Waitmsg) String() string {
str := fmt.Sprintf("Process exited with status %v", w.status)
if w.signal != "" {
str += fmt.Sprintf(" from signal %v", w.signal)
}
if w.msg != "" {
str += fmt.Sprintf(". Reason was: %v", w.msg)
}
return str
}

139
pkg/proto/ssh/ssh_gss.go
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@ -1,139 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"encoding/asn1"
"errors"
)
var krb5OID []byte
func init() {
krb5OID, _ = asn1.Marshal(krb5Mesh)
}
// GSSAPIClient provides the API to plug-in GSSAPI authentication for client logins.
type GSSAPIClient interface {
// InitSecContext initiates the establishment of a security context for GSS-API between the
// ssh client and ssh server. Initially the token parameter should be specified as nil.
// The routine may return a outputToken which should be transferred to
// the ssh server, where the ssh server will present it to
// AcceptSecContext. If no token need be sent, InitSecContext will indicate this by setting
// needContinue to false. To complete the context
// establishment, one or more reply tokens may be required from the ssh
// server;if so, InitSecContext will return a needContinue which is true.
// In this case, InitSecContext should be called again when the
// reply token is received from the ssh server, passing the reply
// token to InitSecContext via the token parameters.
// See RFC 2743 section 2.2.1 and RFC 4462 section 3.4.
InitSecContext(target string, token []byte, isGSSDelegCreds bool) (outputToken []byte, needContinue bool, err error)
// GetMIC generates a cryptographic MIC for the SSH2 message, and places
// the MIC in a token for transfer to the ssh server.
// The contents of the MIC field are obtained by calling GSS_GetMIC()
// over the following, using the GSS-API context that was just
// established:
// string session identifier
// byte SSH_MSG_USERAUTH_REQUEST
// string user name
// string service
// string "gssapi-with-mic"
// See RFC 2743 section 2.3.1 and RFC 4462 3.5.
GetMIC(micFiled []byte) ([]byte, error)
// Whenever possible, it should be possible for
// DeleteSecContext() calls to be successfully processed even
// if other calls cannot succeed, thereby enabling context-related
// resources to be released.
// In addition to deleting established security contexts,
// gss_delete_sec_context must also be able to delete "half-built"
// security contexts resulting from an incomplete sequence of
// InitSecContext()/AcceptSecContext() calls.
// See RFC 2743 section 2.2.3.
DeleteSecContext() error
}
// GSSAPIServer provides the API to plug in GSSAPI authentication for server logins.
type GSSAPIServer interface {
// AcceptSecContext allows a remotely initiated security context between the application
// and a remote peer to be established by the ssh client. The routine may return a
// outputToken which should be transferred to the ssh client,
// where the ssh client will present it to InitSecContext.
// If no token need be sent, AcceptSecContext will indicate this
// by setting the needContinue to false. To
// complete the context establishment, one or more reply tokens may be
// required from the ssh client. if so, AcceptSecContext
// will return a needContinue which is true, in which case it
// should be called again when the reply token is received from the ssh
// client, passing the token to AcceptSecContext via the
// token parameters.
// The srcName return value is the authenticated username.
// See RFC 2743 section 2.2.2 and RFC 4462 section 3.4.
AcceptSecContext(token []byte) (outputToken []byte, srcName string, needContinue bool, err error)
// VerifyMIC verifies that a cryptographic MIC, contained in the token parameter,
// fits the supplied message is received from the ssh client.
// See RFC 2743 section 2.3.2.
VerifyMIC(micField []byte, micToken []byte) error
// Whenever possible, it should be possible for
// DeleteSecContext() calls to be successfully processed even
// if other calls cannot succeed, thereby enabling context-related
// resources to be released.
// In addition to deleting established security contexts,
// gss_delete_sec_context must also be able to delete "half-built"
// security contexts resulting from an incomplete sequence of
// InitSecContext()/AcceptSecContext() calls.
// See RFC 2743 section 2.2.3.
DeleteSecContext() error
}
var (
// OpenSSH supports Kerberos V5 mechanism only for GSS-API authentication,
// so we also support the krb5 mechanism only.
// See RFC 1964 section 1.
krb5Mesh = asn1.ObjectIdentifier{1, 2, 840, 113554, 1, 2, 2}
)
// The GSS-API authentication method is initiated when the client sends an SSH_MSG_USERAUTH_REQUEST
// See RFC 4462 section 3.2.
type userAuthRequestGSSAPI struct {
N uint32
OIDS []asn1.ObjectIdentifier
}
func parseGSSAPIPayload(payload []byte) (*userAuthRequestGSSAPI, error) {
n, rest, ok := parseUint32(payload)
if !ok {
return nil, errors.New("parse uint32 failed")
}
s := &userAuthRequestGSSAPI{
N: n,
OIDS: make([]asn1.ObjectIdentifier, n),
}
for i := 0; i < int(n); i++ {
var (
desiredMech []byte
err error
)
desiredMech, rest, ok = parseString(rest)
if !ok {
return nil, errors.New("parse string failed")
}
if rest, err = asn1.Unmarshal(desiredMech, &s.OIDS[i]); err != nil {
return nil, err
}
}
return s, nil
}
// See RFC 4462 section 3.6.
func buildMIC(sessionID string, username string, service string, authMethod string) []byte {
out := make([]byte, 0, 0)
out = appendString(out, sessionID)
out = append(out, msgUserAuthRequest)
out = appendString(out, username)
out = appendString(out, service)
out = appendString(out, authMethod)
return out
}

116
pkg/proto/ssh/streamlocal.go
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@ -1,116 +0,0 @@
package ssh
import (
"errors"
"io"
"net"
)
// streamLocalChannelOpenDirectMsg is a struct used for SSH_MSG_CHANNEL_OPEN message
// with "direct-streamlocal@openssh.com" string.
//
// See openssh-portable/PROTOCOL, section 2.4. connection: Unix domain socket forwarding
// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL#L235
type streamLocalChannelOpenDirectMsg struct {
socketPath string
reserved0 string
reserved1 uint32
}
// forwardedStreamLocalPayload is a struct used for SSH_MSG_CHANNEL_OPEN message
// with "forwarded-streamlocal@openssh.com" string.
type forwardedStreamLocalPayload struct {
SocketPath string
Reserved0 string
}
// streamLocalChannelForwardMsg is a struct used for SSH2_MSG_GLOBAL_REQUEST message
// with "streamlocal-forward@openssh.com"/"cancel-streamlocal-forward@openssh.com" string.
type streamLocalChannelForwardMsg struct {
socketPath string
}
// ListenUnix is similar to ListenTCP but uses a Unix domain socket.
func (c *Client) ListenUnix(socketPath string) (net.Listener, error) {
c.handleForwardsOnce.Do(c.handleForwards)
m := streamLocalChannelForwardMsg{
socketPath,
}
// send message
ok, _, err := c.SendRequest("streamlocal-forward@openssh.com", true, Marshal(&m))
if err != nil {
return nil, err
}
if !ok {
return nil, errors.New("ssh: streamlocal-forward@openssh.com request denied by peer")
}
ch := c.forwards.add(&net.UnixAddr{Name: socketPath, Net: "unix"})
return &unixListener{socketPath, c, ch}, nil
}
func (c *Client) dialStreamLocal(socketPath string) (Channel, error) {
msg := streamLocalChannelOpenDirectMsg{
socketPath: socketPath,
}
ch, in, err := c.OpenChannel("direct-streamlocal@openssh.com", Marshal(&msg))
if err != nil {
return nil, err
}
go DiscardRequests(in)
return ch, err
}
type unixListener struct {
socketPath string
conn *Client
in <-chan forward
}
// Accept waits for and returns the next connection to the listener.
func (l *unixListener) Accept() (net.Conn, error) {
s, ok := <-l.in
if !ok {
return nil, io.EOF
}
ch, incoming, err := s.newCh.Accept()
if err != nil {
return nil, err
}
go DiscardRequests(incoming)
return &chanConn{
Channel: ch,
laddr: &net.UnixAddr{
Name: l.socketPath,
Net: "unix",
},
raddr: &net.UnixAddr{
Name: "@",
Net: "unix",
},
}, nil
}
// Close closes the listener.
func (l *unixListener) Close() error {
// this also closes the listener.
l.conn.forwards.remove(&net.UnixAddr{Name: l.socketPath, Net: "unix"})
m := streamLocalChannelForwardMsg{
l.socketPath,
}
ok, _, err := l.conn.SendRequest("cancel-streamlocal-forward@openssh.com", true, Marshal(&m))
if err == nil && !ok {
err = errors.New("ssh: cancel-streamlocal-forward@openssh.com failed")
}
return err
}
// Addr returns the listener's network address.
func (l *unixListener) Addr() net.Addr {
return &net.UnixAddr{
Name: l.socketPath,
Net: "unix",
}
}

478
pkg/proto/ssh/tcpip.go
View File

@ -1,478 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"errors"
"fmt"
"io"
"math/rand"
"net"
"strconv"
"strings"
"sync"
"time"
)
// Listen requests the remote peer open a listening socket on
// addr. Incoming connections will be available by calling Accept on
// the returned net.Listener. The listener must be serviced, or the
// SSH connection may hang.
// N must be "tcp", "tcp4", "tcp6", or "unix".
func (c *Client) Listen(n, addr string) (net.Listener, error) {
switch n {
case "tcp", "tcp4", "tcp6":
laddr, err := net.ResolveTCPAddr(n, addr)
if err != nil {
return nil, err
}
return c.ListenTCP(laddr)
case "unix":
return c.ListenUnix(addr)
default:
return nil, fmt.Errorf("ssh: unsupported protocol: %s", n)
}
}
// Automatic port allocation is broken with OpenSSH before 6.0. See
// also https://bugzilla.mindrot.org/show_bug.cgi?id=2017. In
// particular, OpenSSH 5.9 sends a channelOpenMsg with port number 0,
// rather than the actual port number. This means you can never open
// two different listeners with auto allocated ports. We work around
// this by trying explicit ports until we succeed.
const openSSHPrefix = "OpenSSH_"
var portRandomizer = rand.New(rand.NewSource(time.Now().UnixNano()))
// isBrokenOpenSSHVersion returns true if the given version string
// specifies a version of OpenSSH that is known to have a bug in port
// forwarding.
func isBrokenOpenSSHVersion(versionStr string) bool {
i := strings.Index(versionStr, openSSHPrefix)
if i < 0 {
return false
}
i += len(openSSHPrefix)
j := i
for ; j < len(versionStr); j++ {
if versionStr[j] < '0' || versionStr[j] > '9' {
break
}
}
version, _ := strconv.Atoi(versionStr[i:j])
return version < 6
}
// autoPortListenWorkaround simulates automatic port allocation by
// trying random ports repeatedly.
func (c *Client) autoPortListenWorkaround(laddr *net.TCPAddr) (net.Listener, error) {
var sshListener net.Listener
var err error
const tries = 10
for i := 0; i < tries; i++ {
addr := *laddr
addr.Port = 1024 + portRandomizer.Intn(60000)
sshListener, err = c.ListenTCP(&addr)
if err == nil {
laddr.Port = addr.Port
return sshListener, err
}
}
return nil, fmt.Errorf("ssh: listen on random port failed after %d tries: %v", tries, err)
}
// RFC 4254 7.1
type channelForwardMsg struct {
addr string
rport uint32
}
// handleForwards starts goroutines handling forwarded connections.
// It's called on first use by (*Client).ListenTCP to not launch
// goroutines until needed.
func (c *Client) handleForwards() {
go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-tcpip"))
go c.forwards.handleChannels(c.HandleChannelOpen("forwarded-streamlocal@openssh.com"))
}
// ListenTCP requests the remote peer open a listening socket
// on laddr. Incoming connections will be available by calling
// Accept on the returned net.Listener.
func (c *Client) ListenTCP(laddr *net.TCPAddr, fakeHost ...string) (net.Listener, error) {
c.handleForwardsOnce.Do(c.handleForwards)
if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) {
return c.autoPortListenWorkaround(laddr)
}
host := laddr.IP.String()
if len(fakeHost) > 0 {
host = fakeHost[0]
}
m := channelForwardMsg{
host,
uint32(laddr.Port),
}
// send message
ok, resp, err := c.SendRequest("tcpip-forward", true, Marshal(&m))
if err != nil {
return nil, err
}
if !ok {
return nil, errors.New("ssh: tcpip-forward request denied by peer")
}
// If the original port was 0, then the remote side will
// supply a real port number in the response.
if laddr.Port == 0 {
var p struct {
Port uint32
}
if err := Unmarshal(resp, &p); err != nil {
return nil, err
}
laddr.Port = int(p.Port)
}
// Register this forward, using the port number we obtained.
ch := c.forwards.add(laddr)
return &tcpListener{laddr, c, ch}, nil
}
// forwardList stores a mapping between remote
// forward requests and the tcpListeners.
type forwardList struct {
sync.Mutex
entries []forwardEntry
}
// forwardEntry represents an established mapping of a laddr on a
// remote ssh server to a channel connected to a tcpListener.
type forwardEntry struct {
laddr net.Addr
c chan forward
}
// forward represents an incoming forwarded tcpip connection. The
// arguments to add/remove/lookup should be address as specified in
// the original forward-request.
type forward struct {
newCh NewChannel // the ssh client channel underlying this forward
raddr net.Addr // the raddr of the incoming connection
}
func (l *forwardList) add(addr net.Addr) chan forward {
l.Lock()
defer l.Unlock()
f := forwardEntry{
laddr: addr,
c: make(chan forward, 1),
}
l.entries = append(l.entries, f)
return f.c
}
// See RFC 4254, section 7.2
type forwardedTCPPayload struct {
Addr string
Port uint32
OriginAddr string
OriginPort uint32
}
// parseTCPAddr parses the originating address from the remote into a *net.TCPAddr.
func parseTCPAddr(addr string, port uint32) (*net.TCPAddr, error) {
if port == 0 || port > 65535 {
return nil, fmt.Errorf("ssh: port number out of range: %d", port)
}
ip := net.ParseIP(string(addr))
if ip == nil {
return nil, fmt.Errorf("ssh: cannot parse IP address %q", addr)
}
return &net.TCPAddr{IP: ip, Port: int(port)}, nil
}
func (l *forwardList) handleChannels(in <-chan NewChannel) {
for ch := range in {
var (
laddr net.Addr
raddr net.Addr
err error
)
switch channelType := ch.ChannelType(); channelType {
case "forwarded-tcpip":
var payload forwardedTCPPayload
if err = Unmarshal(ch.ExtraData(), &payload); err != nil {
ch.Reject(ConnectionFailed, "could not parse forwarded-tcpip payload: "+err.Error())
continue
}
// RFC 4254 section 7.2 specifies that incoming
// addresses should list the address, in string
// format. It is implied that this should be an IP
// address, as it would be impossible to connect to it
// otherwise.
laddr, err = parseTCPAddr(payload.Addr, payload.Port)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
raddr, err = parseTCPAddr(payload.OriginAddr, payload.OriginPort)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
case "forwarded-streamlocal@openssh.com":
var payload forwardedStreamLocalPayload
if err = Unmarshal(ch.ExtraData(), &payload); err != nil {
ch.Reject(ConnectionFailed, "could not parse forwarded-streamlocal@openssh.com payload: "+err.Error())
continue
}
laddr = &net.UnixAddr{
Name: payload.SocketPath,
Net: "unix",
}
raddr = &net.UnixAddr{
Name: "@",
Net: "unix",
}
default:
panic(fmt.Errorf("ssh: unknown channel type %s", channelType))
}
if ok := l.forward(laddr, raddr, ch); !ok {
// Section 7.2, implementations MUST reject spurious incoming
// connections.
ch.Reject(Prohibited, "no forward for address")
continue
}
}
}
// remove removes the forward entry, and the channel feeding its
// listener.
func (l *forwardList) remove(addr net.Addr) {
l.Lock()
defer l.Unlock()
for i, f := range l.entries {
if addr.Network() == f.laddr.Network() && addr.String() == f.laddr.String() {
l.entries = append(l.entries[:i], l.entries[i+1:]...)
close(f.c)
return
}
}
}
// closeAll closes and clears all forwards.
func (l *forwardList) closeAll() {
l.Lock()
defer l.Unlock()
for _, f := range l.entries {
close(f.c)
}
l.entries = nil
}
func (l *forwardList) forward(laddr, raddr net.Addr, ch NewChannel) bool {
l.Lock()
defer l.Unlock()
for _, f := range l.entries {
if laddr.Network() == f.laddr.Network() && laddr.String() == f.laddr.String() {
f.c <- forward{newCh: ch, raddr: raddr}
return true
}
}
return false
}
type tcpListener struct {
laddr *net.TCPAddr
conn *Client
in <-chan forward
}
// Accept waits for and returns the next connection to the listener.
func (l *tcpListener) Accept() (net.Conn, error) {
s, ok := <-l.in
if !ok {
return nil, io.EOF
}
ch, incoming, err := s.newCh.Accept()
if err != nil {
return nil, err
}
go DiscardRequests(incoming)
return &chanConn{
Channel: ch,
laddr: l.laddr,
raddr: s.raddr,
}, nil
}
// Close closes the listener.
func (l *tcpListener) Close() error {
m := channelForwardMsg{
l.laddr.IP.String(),
uint32(l.laddr.Port),
}
// this also closes the listener.
l.conn.forwards.remove(l.laddr)
ok, _, err := l.conn.SendRequest("cancel-tcpip-forward", true, Marshal(&m))
if err == nil && !ok {
err = errors.New("ssh: cancel-tcpip-forward failed")
}
return err
}
// Addr returns the listener's network address.
func (l *tcpListener) Addr() net.Addr {
return l.laddr
}
// Dial initiates a connection to the addr from the remote host.
// The resulting connection has a zero LocalAddr() and RemoteAddr().
func (c *Client) Dial(n, addr string) (net.Conn, error) {
var ch Channel
switch n {
case "tcp", "tcp4", "tcp6":
// Parse the address into host and numeric port.
host, portString, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
port, err := strconv.ParseUint(portString, 10, 16)
if err != nil {
return nil, err
}
ch, err = c.dial(net.IPv4zero.String(), 0, host, int(port))
if err != nil {
return nil, err
}
// Use a zero address for local and remote address.
zeroAddr := &net.TCPAddr{
IP: net.IPv4zero,
Port: 0,
}
return &chanConn{
Channel: ch,
laddr: zeroAddr,
raddr: zeroAddr,
}, nil
case "unix":
var err error
ch, err = c.dialStreamLocal(addr)
if err != nil {
return nil, err
}
return &chanConn{
Channel: ch,
laddr: &net.UnixAddr{
Name: "@",
Net: "unix",
},
raddr: &net.UnixAddr{
Name: addr,
Net: "unix",
},
}, nil
default:
return nil, fmt.Errorf("ssh: unsupported protocol: %s", n)
}
}
// DialTCP connects to the remote address raddr on the network net,
// which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used
// as the local address for the connection.
func (c *Client) DialTCP(n string, laddr, raddr *net.TCPAddr) (net.Conn, error) {
if laddr == nil {
laddr = &net.TCPAddr{
IP: net.IPv4zero,
Port: 0,
}
}
ch, err := c.dial(laddr.IP.String(), laddr.Port, raddr.IP.String(), raddr.Port)
if err != nil {
return nil, err
}
return &chanConn{
Channel: ch,
laddr: laddr,
raddr: raddr,
}, nil
}
// RFC 4254 7.2
type channelOpenDirectMsg struct {
raddr string
rport uint32
laddr string
lport uint32
}
func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel, error) {
msg := channelOpenDirectMsg{
raddr: raddr,
rport: uint32(rport),
laddr: laddr,
lport: uint32(lport),
}
ch, in, err := c.OpenChannel("direct-tcpip", Marshal(&msg))
if err != nil {
return nil, err
}
go DiscardRequests(in)
return ch, err
}
type tcpChan struct {
Channel // the backing channel
}
// chanConn fulfills the net.Conn interface without
// the tcpChan having to hold laddr or raddr directly.
type chanConn struct {
Channel
laddr, raddr net.Addr
}
// LocalAddr returns the local network address.
func (t *chanConn) LocalAddr() net.Addr {
return t.laddr
}
// RemoteAddr returns the remote network address.
func (t *chanConn) RemoteAddr() net.Addr {
return t.raddr
}
// SetDeadline sets the read and write deadlines associated
// with the connection.
func (t *chanConn) SetDeadline(deadline time.Time) error {
if err := t.SetReadDeadline(deadline); err != nil {
return err
}
return t.SetWriteDeadline(deadline)
}
// SetReadDeadline sets the read deadline.
// A zero value for t means Read will not time out.
// After the deadline, the error from Read will implement net.Error
// with Timeout() == true.
func (t *chanConn) SetReadDeadline(deadline time.Time) error {
// for compatibility with previous version,
// the error message contains "tcpChan"
return errors.New("ssh: tcpChan: deadline not supported")
}
// SetWriteDeadline exists to satisfy the net.Conn interface
// but is not implemented by this type. It always returns an error.
func (t *chanConn) SetWriteDeadline(deadline time.Time) error {
return errors.New("ssh: tcpChan: deadline not supported")
}

76
pkg/proto/ssh/terminal/terminal.go
View File

@ -1,76 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Deprecated: this package moved to golang.org/x/term.
package terminal
import (
"io"
"golang.org/x/term"
)
// EscapeCodes contains escape sequences that can be written to the terminal in
// order to achieve different styles of text.
type EscapeCodes = term.EscapeCodes
// Terminal contains the state for running a VT100 terminal that is capable of
// reading lines of input.
type Terminal = term.Terminal
// NewTerminal runs a VT100 terminal on the given ReadWriter. If the ReadWriter is
// a local terminal, that terminal must first have been put into raw mode.
// prompt is a string that is written at the start of each input line (i.e.
// "> ").
func NewTerminal(c io.ReadWriter, prompt string) *Terminal {
return term.NewTerminal(c, prompt)
}
// ErrPasteIndicator may be returned from ReadLine as the error, in addition
// to valid line data. It indicates that bracketed paste mode is enabled and
// that the returned line consists only of pasted data. Programs may wish to
// interpret pasted data more literally than typed data.
var ErrPasteIndicator = term.ErrPasteIndicator
// State contains the state of a terminal.
type State = term.State
// IsTerminal returns whether the given file descriptor is a terminal.
func IsTerminal(fd int) bool {
return term.IsTerminal(fd)
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, error) {
return term.ReadPassword(fd)
}
// MakeRaw puts the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
func MakeRaw(fd int) (*State, error) {
return term.MakeRaw(fd)
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, oldState *State) error {
return term.Restore(fd, oldState)
}
// GetState returns the current state of a terminal which may be useful to
// restore the terminal after a signal.
func GetState(fd int) (*State, error) {
return term.GetState(fd)
}
// GetSize returns the dimensions of the given terminal.
func GetSize(fd int) (width, height int, err error) {
return term.GetSize(fd)
}

358
pkg/proto/ssh/transport.go
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@ -1,358 +0,0 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bufio"
"bytes"
"errors"
"io"
"log"
)
// debugTransport if set, will print packet types as they go over the
// wire. No message decoding is done, to minimize the impact on timing.
const debugTransport = false
const (
gcm128CipherID = "aes128-gcm@openssh.com"
gcm256CipherID = "aes256-gcm@openssh.com"
aes128cbcID = "aes128-cbc"
tripledescbcID = "3des-cbc"
)
// packetConn represents a transport that implements packet based
// operations.
type packetConn interface {
// Encrypt and send a packet of data to the remote peer.
writePacket(packet []byte) error
// Read a packet from the connection. The read is blocking,
// i.e. if error is nil, then the returned byte slice is
// always non-empty.
readPacket() ([]byte, error)
// Close closes the write-side of the connection.
Close() error
}
// transport is the keyingTransport that implements the SSH packet
// protocol.
type transport struct {
reader connectionState
writer connectionState
bufReader *bufio.Reader
bufWriter *bufio.Writer
rand io.Reader
isClient bool
io.Closer
}
// packetCipher represents a combination of SSH encryption/MAC
// protocol. A single instance should be used for one direction only.
type packetCipher interface {
// writeCipherPacket encrypts the packet and writes it to w. The
// contents of the packet are generally scrambled.
writeCipherPacket(seqnum uint32, w io.Writer, rand io.Reader, packet []byte) error
// readCipherPacket reads and decrypts a packet of data. The
// returned packet may be overwritten by future calls of
// readPacket.
readCipherPacket(seqnum uint32, r io.Reader) ([]byte, error)
}
// connectionState represents one side (read or write) of the
// connection. This is necessary because each direction has its own
// keys, and can even have its own algorithms
type connectionState struct {
packetCipher
seqNum uint32
dir direction
pendingKeyChange chan packetCipher
}
// prepareKeyChange sets up key material for a keychange. The key changes in
// both directions are triggered by reading and writing a msgNewKey packet
// respectively.
func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error {
ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult)
if err != nil {
return err
}
t.reader.pendingKeyChange <- ciph
ciph, err = newPacketCipher(t.writer.dir, algs.w, kexResult)
if err != nil {
return err
}
t.writer.pendingKeyChange <- ciph
return nil
}
func (t *transport) printPacket(p []byte, write bool) {
if len(p) == 0 {
return
}
who := "server"
if t.isClient {
who = "client"
}
what := "read"
if write {
what = "write"
}
log.Println(what, who, p[0])
}
// Read and decrypt next packet.
func (t *transport) readPacket() (p []byte, err error) {
for {
p, err = t.reader.readPacket(t.bufReader)
if err != nil {
break
}
if len(p) == 0 || (p[0] != msgIgnore && p[0] != msgDebug) {
break
}
}
if debugTransport {
t.printPacket(p, false)
}
return p, err
}
func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) {
packet, err := s.packetCipher.readCipherPacket(s.seqNum, r)
s.seqNum++
if err == nil && len(packet) == 0 {
err = errors.New("ssh: zero length packet")
}
if len(packet) > 0 {
switch packet[0] {
case msgNewKeys:
select {
case cipher := <-s.pendingKeyChange:
s.packetCipher = cipher
default:
return nil, errors.New("ssh: got bogus newkeys message")
}
case msgDisconnect:
// Transform a disconnect message into an
// error. Since this is lowest level at which
// we interpret message types, doing it here
// ensures that we don't have to handle it
// elsewhere.
var msg disconnectMsg
if err := Unmarshal(packet, &msg); err != nil {
return nil, err
}
return nil, &msg
}
}
// The packet may point to an internal buffer, so copy the
// packet out here.
fresh := make([]byte, len(packet))
copy(fresh, packet)
return fresh, err
}
func (t *transport) writePacket(packet []byte) error {
if debugTransport {
t.printPacket(packet, true)
}
return t.writer.writePacket(t.bufWriter, t.rand, packet)
}
func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte) error {
changeKeys := len(packet) > 0 && packet[0] == msgNewKeys
err := s.packetCipher.writeCipherPacket(s.seqNum, w, rand, packet)
if err != nil {
return err
}
if err = w.Flush(); err != nil {
return err
}
s.seqNum++
if changeKeys {
select {
case cipher := <-s.pendingKeyChange:
s.packetCipher = cipher
default:
panic("ssh: no key material for msgNewKeys")
}
}
return err
}
func newTransport(rwc io.ReadWriteCloser, rand io.Reader, isClient bool) *transport {
t := &transport{
bufReader: bufio.NewReader(rwc),
bufWriter: bufio.NewWriter(rwc),
rand: rand,
reader: connectionState{
packetCipher: &streamPacketCipher{cipher: noneCipher{}},
pendingKeyChange: make(chan packetCipher, 1),
},
writer: connectionState{
packetCipher: &streamPacketCipher{cipher: noneCipher{}},
pendingKeyChange: make(chan packetCipher, 1),
},
Closer: rwc,
}
t.isClient = isClient
if isClient {
t.reader.dir = serverKeys
t.writer.dir = clientKeys
} else {
t.reader.dir = clientKeys
t.writer.dir = serverKeys
}
return t
}
type direction struct {
ivTag []byte
keyTag []byte
macKeyTag []byte
}
var (
serverKeys = direction{[]byte{'B'}, []byte{'D'}, []byte{'F'}}
clientKeys = direction{[]byte{'A'}, []byte{'C'}, []byte{'E'}}
)
// setupKeys sets the cipher and MAC keys from kex.K, kex.H and sessionId, as
// described in RFC 4253, section 6.4. direction should either be serverKeys
// (to setup server->client keys) or clientKeys (for client->server keys).
func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) {
cipherMode := cipherModes[algs.Cipher]
iv := make([]byte, cipherMode.ivSize)
key := make([]byte, cipherMode.keySize)
generateKeyMaterial(iv, d.ivTag, kex)
generateKeyMaterial(key, d.keyTag, kex)
var macKey []byte
if !aeadCiphers[algs.Cipher] {
macMode := macModes[algs.MAC]
macKey = make([]byte, macMode.keySize)
generateKeyMaterial(macKey, d.macKeyTag, kex)
}
return cipherModes[algs.Cipher].create(key, iv, macKey, algs)
}
// generateKeyMaterial fills out with key material generated from tag, K, H
// and sessionId, as specified in RFC 4253, section 7.2.
func generateKeyMaterial(out, tag []byte, r *kexResult) {
var digestsSoFar []byte
h := r.Hash.New()
for len(out) > 0 {
h.Reset()
h.Write(r.K)
h.Write(r.H)
if len(digestsSoFar) == 0 {
h.Write(tag)
h.Write(r.SessionID)
} else {
h.Write(digestsSoFar)
}
digest := h.Sum(nil)
n := copy(out, digest)
out = out[n:]
if len(out) > 0 {
digestsSoFar = append(digestsSoFar, digest...)
}
}
}
const packageVersion = "SSH-2.0-Go"
// Sends and receives a version line. The versionLine string should
// be US ASCII, start with "SSH-2.0-", and should not include a
// newline. exchangeVersions returns the other side's version line.
func exchangeVersions(rw io.ReadWriter, versionLine []byte) (them []byte, err error) {
// Contrary to the RFC, we do not ignore lines that don't
// start with "SSH-2.0-" to make the library usable with
// nonconforming servers.
for _, c := range versionLine {
// The spec disallows non US-ASCII chars, and
// specifically forbids null chars.
if c < 32 {
return nil, errors.New("ssh: junk character in version line")
}
}
if _, err = rw.Write(append(versionLine, '\r', '\n')); err != nil {
return
}
them, err = readVersion(rw)
return them, err
}
// maxVersionStringBytes is the maximum number of bytes that we'll
// accept as a version string. RFC 4253 section 4.2 limits this at 255
// chars
const maxVersionStringBytes = 255
// Read version string as specified by RFC 4253, section 4.2.
func readVersion(r io.Reader) ([]byte, error) {
versionString := make([]byte, 0, 64)
var ok bool
var buf [1]byte
for length := 0; length < maxVersionStringBytes; length++ {
_, err := io.ReadFull(r, buf[:])
if err != nil {
return nil, err
}
// The RFC says that the version should be terminated with \r\n
// but several SSH servers actually only send a \n.
if buf[0] == '\n' {
if !bytes.HasPrefix(versionString, []byte("SSH-")) {
// RFC 4253 says we need to ignore all version string lines
// except the one containing the SSH version (provided that
// all the lines do not exceed 255 bytes in total).
versionString = versionString[:0]
continue
}
ok = true
break
}
// non ASCII chars are disallowed, but we are lenient,
// since Go doesn't use null-terminated strings.
// The RFC allows a comment after a space, however,
// all of it (version and comments) goes into the
// session hash.
versionString = append(versionString, buf[0])
}
if !ok {
return nil, errors.New("ssh: overflow reading version string")
}
// There might be a '\r' on the end which we should remove.
if len(versionString) > 0 && versionString[len(versionString)-1] == '\r' {
versionString = versionString[:len(versionString)-1]
}
return versionString, nil
}