naiveproxy/net/cert/internal/verify_certificate_chain.h
2018-01-29 00:30:36 +08:00

242 lines
8.4 KiB
C++

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_CERT_INTERNAL_VERIFY_CERTIFICATE_CHAIN_H_
#define NET_CERT_INTERNAL_VERIFY_CERTIFICATE_CHAIN_H_
#include <set>
#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"
#include "net/base/net_export.h"
#include "net/cert/internal/cert_errors.h"
#include "net/cert/internal/parsed_certificate.h"
#include "net/der/input.h"
#include "third_party/boringssl/src/include/openssl/evp.h"
namespace net {
namespace der {
struct GeneralizedTime;
}
struct CertificateTrust;
// The key purpose (extended key usage) to check for during verification.
enum class KeyPurpose {
ANY_EKU,
SERVER_AUTH,
CLIENT_AUTH,
};
enum class InitialExplicitPolicy {
kFalse,
kTrue,
};
enum class InitialPolicyMappingInhibit {
kFalse,
kTrue,
};
enum class InitialAnyPolicyInhibit {
kFalse,
kTrue,
};
// VerifyCertificateChainDelegate exposes delegate methods used when verifying a
// chain.
class NET_EXPORT VerifyCertificateChainDelegate {
public:
// Implementations should return true if |signature_algorithm| is allowed for
// certificate signing, false otherwise. When returning false implementations
// can optionally add high-severity errors to |errors| with details on why it
// was rejected.
virtual bool IsSignatureAlgorithmAcceptable(
const SignatureAlgorithm& signature_algorithm,
CertErrors* errors) = 0;
// Implementations should return true if |public_key| is acceptable. This is
// called for each certificate in the chain, including the target certificate.
// When returning false implementations can optionally add high-severity
// errors to |errors| with details on why it was rejected.
//
// |public_key| can be assumed to be non-null.
virtual bool IsPublicKeyAcceptable(EVP_PKEY* public_key,
CertErrors* errors) = 0;
virtual ~VerifyCertificateChainDelegate();
};
// VerifyCertificateChain() verifies an ordered certificate path in accordance
// with RFC 5280's "Certification Path Validation" algorithm (section 6).
//
// -----------------------------------------
// Deviations from RFC 5280
// -----------------------------------------
//
// * If Extended Key Usage appears on intermediates, it is treated as
// a restriction on subordinate certificates.
//
// -----------------------------------------
// Additional responsibilities of the caller
// -----------------------------------------
//
// After successful path verification, the caller is responsible for
// subsequently checking:
//
// * The end-entity's KeyUsage before using its SPKI.
// * The end-entity's name/subjectAltName. Name constraints from intermediates
// will have already been applied, so it is sufficient to check the
// end-entity for a match.
//
// ---------
// Inputs
// ---------
//
// certs:
// A non-empty chain of DER-encoded certificates, listed in the
// "forward" direction. The first certificate is the target
// certificate to verify, and the last certificate has trustedness
// given by |last_cert_trust| (generally a trust anchor).
//
// * certs[0] is the target certificate to verify.
// * certs[i+1] holds the certificate that issued cert_chain[i].
// * certs[N-1] the root certificate
//
// Note that THIS IS NOT identical in meaning to the same named
// "certs" input defined in RFC 5280 section 6.1.1.a. The differences
// are:
//
// * The order of certificates is reversed
// * In RFC 5280 "certs" DOES NOT include the trust anchor
//
// last_cert_trust:
// Trustedness of |certs.back()|. The trustedness of |certs.back()|
// MUST BE decided by the caller -- this function takes it purely as
// an input. Moreover, the CertificateTrust can be used to specify
// trust anchor constraints.
//
// This combined with |certs.back()| (the root certificate) fills a
// similar role to "trust anchor information" defined in RFC 5280
// section 6.1.1.d.
//
// delegate:
// |delegate| must be non-null. It is used to answer policy questions such
// as whether a signature algorithm is acceptable, or a public key is strong
// enough.
//
// time:
// The UTC time to use for expiration checks. This is equivalent to
// the input from RFC 5280 section 6.1.1:
//
// (b) the current date/time.
//
// required_key_purpose:
// The key purpose that the target certificate needs to be valid for.
//
// user_initial_policy_set:
// This is equivalent to the same named input in RFC 5280 section
// 6.1.1:
//
// (c) user-initial-policy-set: A set of certificate policy
// identifiers naming the policies that are acceptable to the
// certificate user. The user-initial-policy-set contains the
// special value any-policy if the user is not concerned about
// certificate policy.
//
// initial_policy_mapping_inhibit:
// This is equivalent to the same named input in RFC 5280 section
// 6.1.1:
//
// (e) initial-policy-mapping-inhibit, which indicates if policy
// mapping is allowed in the certification path.
//
// initial_explicit_policy:
// This is equivalent to the same named input in RFC 5280 section
// 6.1.1:
//
// (f) initial-explicit-policy, which indicates if the path must be
// valid for at least one of the certificate policies in the
// user-initial-policy-set.
//
// initial_any_policy_inhibit:
// This is equivalent to the same named input in RFC 5280 section
// 6.1.1:
//
// (g) initial-any-policy-inhibit, which indicates whether the
// anyPolicy OID should be processed if it is included in a
// certificate.
//
// ---------
// Outputs
// ---------
//
// user_constrained_policy_set:
// Can be null. If non-null, |user_constrained_policy_set| will be filled
// with the matching policies (intersected with user_initial_policy_set).
// This is equivalent to the same named output in X.509 section 10.2.
// Note that it is OK for this to point to input user_initial_policy_set.
//
// errors:
// Must be non-null. The set of errors/warnings encountered while
// validating the path are appended to this structure. If verification
// failed, then there is guaranteed to be at least 1 high severity error
// written to |errors|.
//
// -------------------------
// Trust Anchor constraints
// -------------------------
//
// Conceptually, VerifyCertificateChain() sets RFC 5937's
// "enforceTrustAnchorConstraints" to true.
//
// One specifies trust anchor constraints using the |last_cert_trust|
// parameter in conjunction with extensions appearing in |certs.back()|.
//
// The trust anchor |certs.back()| is always passed as a certificate to
// this function, however the manner in which that certificate is
// interpreted depends on |last_cert_trust|:
//
// TRUSTED_ANCHOR:
//
// No properties from the root certificate, other than its Subject and
// SPKI, are checked during verification. This is the usual
// interpretation for a "trust anchor".
//
// TRUSTED_ANCHOR_WITH_CONSTRAINTS:
//
// Only a subset of extensions and properties from the certificate are checked,
// as described by RFC 5937.
//
// * Signature: No
// * Validity (expiration): No
// * Key usage: No
// * Extended key usage: Yes (not part of RFC 5937)
// * Basic constraints: Yes, but only the pathlen (CA=false is accepted)
// * Name constraints: Yes
// * Certificate policies: Not currently, TODO(crbug.com/634453)
// * Policy Mappings: No
// * inhibitAnyPolicy: Not currently, TODO(crbug.com/634453)
// * PolicyConstraints: Not currently, TODO(crbug.com/634452)
//
// The presence of any other unrecognized extension marked as critical fails
// validation.
NET_EXPORT void VerifyCertificateChain(
const ParsedCertificateList& certs,
const CertificateTrust& last_cert_trust,
VerifyCertificateChainDelegate* delegate,
const der::GeneralizedTime& time,
KeyPurpose required_key_purpose,
InitialExplicitPolicy initial_explicit_policy,
const std::set<der::Input>& user_initial_policy_set,
InitialPolicyMappingInhibit initial_policy_mapping_inhibit,
InitialAnyPolicyInhibit initial_any_policy_inhibit,
std::set<der::Input>* user_constrained_policy_set,
CertPathErrors* errors);
} // namespace net
#endif // NET_CERT_INTERNAL_VERIFY_CERTIFICATE_CHAIN_H_