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Miscellaneous improvements

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This commit contains lots changes which are not very significant on its own but
provide important usability improvements and future proofing.

It also includes changes which required OpenVPN v2.4+ and were pending until
that version became widely available.

- General cleanup
- Improved IP address and NAT configuration
- Added input validation and sanitization
- Fix #603
- Remove "sndbuf" and "recvbuf" parameters
- Add server-side "explicit-exit-notify"
- Switch from "setenv opt" to "ignore-unknown-option"
- Switch from "tls-auth" to "tls-crypt"
- Other minor bugfixes and optimizations
This commit is contained in:
Nyr 2019-09-26 19:13:33 +02:00
parent 68e48d21b6
commit 6a29a6babd
1 changed files with 168 additions and 123 deletions
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289
openvpn-install.sh
View File

@ -5,22 +5,22 @@
# Copyright (c) 2013 Nyr. Released under the MIT License. # Copyright (c) 2013 Nyr. Released under the MIT License.
if grep -qs "14.04" "/etc/os-release"; then if grep -qs "14.04" /etc/os-release; then
echo "Ubuntu 14.04 is too old and not supported" echo "Ubuntu 14.04 is too old and not supported"
exit exit
fi fi
if grep -qs "jessie" "/etc/os-release"; then if grep -qs "jessie" /etc/os-release; then
echo "Debian 8 is too old and not supported" echo "Debian 8 is too old and not supported"
exit exit
fi fi
if grep -qs "CentOS release 6" "/etc/redhat-release"; then if grep -qs "CentOS release 6" /etc/redhat-release; then
echo "CentOS 6 is too old and not supported" echo "CentOS 6 is too old and not supported"
exit exit
fi fi
if grep -qs "Ubuntu 16.04" "/etc/os-release"; then if grep -qs "Ubuntu 16.04" /etc/os-release; then
echo 'Ubuntu 16.04 is no longer supported in the current version of openvpn-install echo 'Ubuntu 16.04 is no longer supported in the current version of openvpn-install
Use an older version if Ubuntu 16.04 support is needed: https://git.io/vpn1604' Use an older version if Ubuntu 16.04 support is needed: https://git.io/vpn1604'
exit exit
@ -44,31 +44,33 @@ You need to enable TUN before running this script"
fi fi
if [[ -e /etc/debian_version ]]; then if [[ -e /etc/debian_version ]]; then
OS=debian os="debian"
GROUPNAME=nogroup group_name="nogroup"
elif [[ -e /etc/centos-release || -e /etc/redhat-release ]]; then elif [[ -e /etc/centos-release || -e /etc/redhat-release ]]; then
OS=centos os="centos"
GROUPNAME=nobody group_name="nobody"
else else
echo "Looks like you aren't running this installer on Debian, Ubuntu or CentOS" echo "Looks like you aren't running this installer on Debian, Ubuntu or CentOS"
exit exit
fi fi
newclient () { new_client () {
# Generates the custom client.ovpn # Generates the custom client.ovpn
cp /etc/openvpn/server/client-common.txt ~/$1.ovpn {
echo "<ca>" >> ~/$1.ovpn cat /etc/openvpn/server/client-common.txt
cat /etc/openvpn/server/easy-rsa/pki/ca.crt >> ~/$1.ovpn echo "<ca>"
echo "</ca>" >> ~/$1.ovpn cat /etc/openvpn/server/easy-rsa/pki/ca.crt
echo "<cert>" >> ~/$1.ovpn echo "</ca>"
sed -ne '/BEGIN CERTIFICATE/,$ p' /etc/openvpn/server/easy-rsa/pki/issued/$1.crt >> ~/$1.ovpn echo "<cert>"
echo "</cert>" >> ~/$1.ovpn sed -ne '/BEGIN CERTIFICATE/,$ p' /etc/openvpn/server/easy-rsa/pki/issued/"$1".crt
echo "<key>" >> ~/$1.ovpn echo "</cert>"
cat /etc/openvpn/server/easy-rsa/pki/private/$1.key >> ~/$1.ovpn echo "<key>"
echo "</key>" >> ~/$1.ovpn cat /etc/openvpn/server/easy-rsa/pki/private/"$1".key
echo "<tls-auth>" >> ~/$1.ovpn echo "</key>"
sed -ne '/BEGIN OpenVPN Static key/,$ p' /etc/openvpn/server/ta.key >> ~/$1.ovpn echo "<tls-crypt>"
echo "</tls-auth>" >> ~/$1.ovpn sed -ne '/BEGIN OpenVPN Static key/,$ p' /etc/openvpn/server/tc.key
echo "</tls-crypt>"
} > ~/"$1".ovpn
} }
if [[ -e /etc/openvpn/server/server.conf ]]; then if [[ -e /etc/openvpn/server/server.conf ]]; then
@ -82,26 +84,35 @@ if [[ -e /etc/openvpn/server/server.conf ]]; then
echo " 2) Revoke an existing user" echo " 2) Revoke an existing user"
echo " 3) Remove OpenVPN" echo " 3) Remove OpenVPN"
echo " 4) Exit" echo " 4) Exit"
read -p "Select an option [1-4]: " option read -p "Select an option: " option
case $option in until [[ "$option" =~ ^[1-4]$ ]]; do
echo "$option: invalid selection."
read -p "Select an option: " option
done
case "$option" in
1) 1)
echo echo
echo "Tell me a name for the client certificate." echo "Tell me a name for the client certificate."
echo "Please, use one word only, no special characters." read -p "Client name: " unsanitized_client
read -p "Client name: " -e CLIENT client=$(sed 's/[^0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-]/_/g' <<< "$unsanitized_client")
while [[ -z "$client" || -e /etc/openvpn/server/easy-rsa/pki/issued/"$client".crt ]]; do
echo "$client: invalid client name."
read -p "Client name: " unsanitized_client
client=$(sed 's/[^0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-]/_/g' <<< "$unsanitized_client")
done
cd /etc/openvpn/server/easy-rsa/ cd /etc/openvpn/server/easy-rsa/
EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-client-full $CLIENT nopass EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-client-full "$client" nopass
# Generates the custom client.ovpn # Generates the custom client.ovpn
newclient "$CLIENT" new_client "$client"
echo echo
echo "Client $CLIENT added, configuration is available at:" ~/"$CLIENT.ovpn" echo "Client $client added, configuration is available at:" ~/"$client.ovpn"
exit exit
;; ;;
2) 2)
# This option could be documented a bit better and maybe even be simplified # This option could be documented a bit better and maybe even be simplified
# ...but what can I say, I want some sleep too # ...but what can I say, I want some sleep too
NUMBEROFCLIENTS=$(tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep -c "^V") number_of_clients=$(tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep -c "^V")
if [[ "$NUMBEROFCLIENTS" = '0' ]]; then if [[ "$number_of_clients" = 0 ]]; then
echo echo
echo "You have no existing clients!" echo "You have no existing clients!"
exit exit
@ -109,60 +120,68 @@ if [[ -e /etc/openvpn/server/server.conf ]]; then
echo echo
echo "Select the existing client certificate you want to revoke:" echo "Select the existing client certificate you want to revoke:"
tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | nl -s ') ' tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | nl -s ') '
if [[ "$NUMBEROFCLIENTS" = '1' ]]; then read -p "Select one client: " client_number
read -p "Select one client [1]: " CLIENTNUMBER until [[ "$client_number" =~ ^[0-9]+$ && "$client_number" -le "$number_of_clients" ]]; do
else echo "$client_number: invalid selection."
read -p "Select one client [1-$NUMBEROFCLIENTS]: " CLIENTNUMBER read -p "Select one client: " client_number
fi done
CLIENT=$(tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | sed -n "$CLIENTNUMBER"p) client=$(tail -n +2 /etc/openvpn/server/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | sed -n "$client_number"p)
echo echo
read -p "Do you really want to revoke access for client $CLIENT? [y/N]: " -e REVOKE read -p "Do you really want to revoke access for client $client? [y/N]: " revoke
if [[ "$REVOKE" = 'y' || "$REVOKE" = 'Y' ]]; then until [[ "$revoke" =~ ^[yYnN]*$ ]]; do
echo "$revoke: invalid selection."
read -p "Do you really want to revoke access for client $client? [y/N]: " revoke
done
if [[ "$revoke" =~ ^[yY]$ ]]; then
cd /etc/openvpn/server/easy-rsa/ cd /etc/openvpn/server/easy-rsa/
./easyrsa --batch revoke $CLIENT ./easyrsa --batch revoke "$client"
EASYRSA_CRL_DAYS=3650 ./easyrsa gen-crl EASYRSA_CRL_DAYS=3650 ./easyrsa gen-crl
rm -f pki/reqs/$CLIENT.req rm -f pki/reqs/"$client".req
rm -f pki/private/$CLIENT.key rm -f pki/private/"$client".key
rm -f pki/issued/$CLIENT.crt rm -f pki/issued/"$client".crt
rm -f /etc/openvpn/server/crl.pem rm -f /etc/openvpn/server/crl.pem
cp /etc/openvpn/server/easy-rsa/pki/crl.pem /etc/openvpn/server/crl.pem cp /etc/openvpn/server/easy-rsa/pki/crl.pem /etc/openvpn/server/crl.pem
# CRL is read with each client connection, when OpenVPN is dropped to nobody # CRL is read with each client connection, when OpenVPN is dropped to nobody
chown nobody:$GROUPNAME /etc/openvpn/server/crl.pem chown nobody:"$group_name" /etc/openvpn/server/crl.pem
echo echo
echo "Certificate for client $CLIENT revoked!" echo "Certificate for client $client revoked!"
else else
echo echo
echo "Certificate revocation for client $CLIENT aborted!" echo "Certificate revocation for client $client aborted!"
fi fi
exit exit
;; ;;
3) 3)
echo echo
read -p "Do you really want to remove OpenVPN? [y/N]: " -e REMOVE read -p "Do you really want to remove OpenVPN? [y/N]: " remove
if [[ "$REMOVE" = 'y' || "$REMOVE" = 'Y' ]]; then until [[ "$remove" =~ ^[yYnN]*$ ]]; do
PORT=$(grep '^port ' /etc/openvpn/server/server.conf | cut -d " " -f 2) echo "$remove: invalid selection."
PROTOCOL=$(grep '^proto ' /etc/openvpn/server/server.conf | cut -d " " -f 2) read -p "Do you really want to remove OpenVPN? [y/N]: " remove
done
if [[ "$remove" =~ ^[yY]$ ]]; then
port=$(grep '^port ' /etc/openvpn/server/server.conf | cut -d " " -f 2)
protocol=$(grep '^proto ' /etc/openvpn/server/server.conf | cut -d " " -f 2)
if pgrep firewalld; then if pgrep firewalld; then
IP=$(firewall-cmd --direct --get-rules ipv4 nat POSTROUTING | grep '\-s 10.8.0.0/24 '"'"'!'"'"' -d 10.8.0.0/24 -j SNAT --to ' | cut -d " " -f 10) ip=$(firewall-cmd --direct --get-rules ipv4 nat POSTROUTING | grep '\-s 10.8.0.0/24 '"'"'!'"'"' -d 10.8.0.0/24 -j SNAT --to ' | cut -d " " -f 10)
# Using both permanent and not permanent rules to avoid a firewalld reload. # Using both permanent and not permanent rules to avoid a firewalld reload.
firewall-cmd --remove-port=$PORT/$PROTOCOL firewall-cmd --remove-port="$port"/"$protocol"
firewall-cmd --zone=trusted --remove-source=10.8.0.0/24 firewall-cmd --zone=trusted --remove-source=10.8.0.0/24
firewall-cmd --permanent --remove-port=$PORT/$PROTOCOL firewall-cmd --permanent --remove-port="$port"/"$protocol"
firewall-cmd --permanent --zone=trusted --remove-source=10.8.0.0/24 firewall-cmd --permanent --zone=trusted --remove-source=10.8.0.0/24
firewall-cmd --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP firewall-cmd --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to "$ip"
firewall-cmd --permanent --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP firewall-cmd --permanent --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to "$ip"
else else
systemctl disable --now openvpn-iptables.service systemctl disable --now openvpn-iptables.service
rm -f /etc/systemd/system/openvpn-iptables.service rm -f /etc/systemd/system/openvpn-iptables.service
fi fi
if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$PORT" != '1194' ]]; then if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$port" != 1194 ]]; then
semanage port -d -t openvpn_port_t -p $PROTOCOL $PORT semanage port -d -t openvpn_port_t -p "$protocol" "$port"
fi fi
systemctl disable --now openvpn-server@server.service systemctl disable --now openvpn-server@server.service
rm -rf /etc/openvpn/server rm -rf /etc/openvpn/server
rm -f /etc/systemd/system/openvpn-server@server.service.d/disable-limitnproc.conf rm -f /etc/systemd/system/openvpn-server@server.service.d/disable-limitnproc.conf
rm -f /etc/sysctl.d/30-openvpn-forward.conf rm -f /etc/sysctl.d/30-openvpn-forward.conf
if [[ "$OS" = 'debian' ]]; then if [[ "$os" = "debian" ]]; then
apt-get remove --purge -y openvpn apt-get remove --purge -y openvpn
else else
yum remove openvpn -y yum remove openvpn -y
@ -180,39 +199,59 @@ if [[ -e /etc/openvpn/server/server.conf ]]; then
done done
else else
clear clear
echo 'Welcome to this OpenVPN "road warrior" installer!' echo "Welcome to this OpenVPN "road warrior" installer!"
echo echo
# OpenVPN setup and first user creation echo "I need to ask you a few questions before starting setup."
echo "I need to ask you a few questions before starting the setup." echo "You can use the default options and just press enter if you are ok with them."
echo "You can leave the default options and just press enter if you are ok with them." # If system has a single IPv4, it is selected automatically. Else, ask the user
if [[ $(ip addr | grep inet | grep -v inet6 | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}') -eq 1 ]]; then
ip=$(ip addr | grep inet | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
else
number_of_ips=$(ip addr | grep inet | grep -v inet6 | grep -vEc '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}')
echo echo
echo "First, provide the IPv4 address of the network interface you want OpenVPN" echo "What IPv4 address should the OpenVPN server bind to?"
echo "listening to." ip addr | grep inet | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | nl -s ') '
# Autodetect IP address and pre-fill for the user read -p "IPv4 address [1]: " ip_number
IP=$(ip addr | grep 'inet' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | head -1) until [[ -z "$ip_number" || "$ip_number" =~ ^[0-9]+$ && "$ip_number" -le "$number_of_ips" ]]; do
read -p "IP address: " -e -i $IP IP echo "$ip_number: invalid selection."
read -p "IPv4 address [1]: " ip_number
done
[[ -z "$ip_number" ]] && ip_number="1"
ip=$(ip addr | grep inet | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d '/' -f 1 | grep -oE '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | sed -n "$ip_number"p)
fi
# If $IP is a private IP address, the server must be behind NAT # If $IP is a private IP address, the server must be behind NAT
if echo "$IP" | grep -qE '^(10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.|192\.168)'; then if echo "$ip" | grep -qE '^(10\.|172\.1[6789]\.|172\.2[0-9]\.|172\.3[01]\.|192\.168)'; then
echo echo
echo "This server is behind NAT. What is the public IPv4 address or hostname?" echo "This server is behind NAT. What is the public IPv4 address or hostname?"
read -p "Public IP address / hostname: " -e PUBLICIP get_public_ip=$(wget -4qO- "http://whatismyip.akamai.com/" || curl -4Ls "http://whatismyip.akamai.com/")
read -p "Public IPv4 address / hostname [$get_public_ip]: " public_ip
[ -z "$public_ip" ] && public_ip="$get_public_ip"
fi fi
echo echo
echo "Which protocol do you want for OpenVPN connections?" echo "Which protocol do you want for OpenVPN connections?"
echo " 1) UDP (recommended)" echo " 1) UDP (recommended)"
echo " 2) TCP" echo " 2) TCP"
read -p "Protocol [1-2]: " -e -i 1 PROTOCOL read -p "Protocol [1]: " protocol
case $PROTOCOL in until [[ -z "$protocol" || "$protocol" =~ ^[12]$ ]]; do
1) echo "$protocol: invalid selection."
PROTOCOL=udp read -p "Protocol [1]: " protocol
done
case "$protocol" in
1|"")
protocol=udp
;; ;;
2) 2)
PROTOCOL=tcp protocol=tcp
;; ;;
esac esac
echo echo
echo "What port do you want OpenVPN listening to?" echo "What port do you want OpenVPN listening to?"
read -p "Port: " -e -i 1194 PORT read -p "Port [1194]: " port
until [[ -z "$port" || "$port" =~ ^[0-9]+$ && "$port" -le 65535 ]]; do
echo "$port: invalid selection."
read -p "Port [1194]: " port
done
[[ -z "$port" ]] && port="1194"
echo echo
echo "Which DNS do you want to use with the VPN?" echo "Which DNS do you want to use with the VPN?"
echo " 1) Current system resolvers" echo " 1) Current system resolvers"
@ -220,21 +259,27 @@ else
echo " 3) Google" echo " 3) Google"
echo " 4) OpenDNS" echo " 4) OpenDNS"
echo " 5) Verisign" echo " 5) Verisign"
read -p "DNS [1-5]: " -e -i 1 DNS read -p "DNS [1]: " dns
until [[ -z "$dns" || "$dns" =~ ^[1-5]$ ]]; do
echo "$dns: invalid selection."
read -p "DNS [1]: " dns
done
echo echo
echo "Finally, tell me your name for the client certificate." echo "Finally, tell me a name for the client certificate."
echo "Please, use one word only, no special characters." read -p "Client name [client]: " unsanitized_client
read -p "Client name: " -e -i client CLIENT # Allow a limited set of characters to avoid conflicts
client=$(sed 's/[^0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-]/_/g' <<< "$unsanitized_client")
[[ -z "$client" ]] && client="client"
echo echo
echo "Okay, that was all I needed. We are ready to set up your OpenVPN server now." echo "Okay, that was all I needed. We are ready to set up your OpenVPN server now."
read -n1 -r -p "Press any key to continue..." read -n1 -r -p "Press any key to continue..."
# If running inside a container, disable LimitNPROC to prevent conflicts # If running inside a container, disable LimitNPROC to prevent conflicts
if systemd-detect-virt -cq; then if systemd-detect-virt -cq; then
mkdir /etc/systemd/system/openvpn-server@server.service.d/ 2>/dev/null mkdir /etc/systemd/system/openvpn-server@server.service.d/ 2>/dev/null
echo '[Service] echo "[Service]
LimitNPROC=infinity' > /etc/systemd/system/openvpn-server@server.service.d/disable-limitnproc.conf LimitNPROC=infinity" > /etc/systemd/system/openvpn-server@server.service.d/disable-limitnproc.conf
fi fi
if [[ "$OS" = 'debian' ]]; then if [[ "$os" = "debian" ]]; then
apt-get update apt-get update
apt-get install openvpn iptables openssl ca-certificates -y apt-get install openvpn iptables openssl ca-certificates -y
else else
@ -243,8 +288,8 @@ LimitNPROC=infinity' > /etc/systemd/system/openvpn-server@server.service.d/disab
yum install openvpn iptables openssl ca-certificates -y yum install openvpn iptables openssl ca-certificates -y
fi fi
# Get easy-rsa # Get easy-rsa
EASYRSAURL='https://github.com/OpenVPN/easy-rsa/releases/download/v3.0.5/EasyRSA-nix-3.0.5.tgz' easy_rsa_url='https://github.com/OpenVPN/easy-rsa/releases/download/v3.0.5/EasyRSA-nix-3.0.5.tgz'
wget -O ~/easyrsa.tgz "$EASYRSAURL" 2>/dev/null || curl -Lo ~/easyrsa.tgz "$EASYRSAURL" wget -O ~/easyrsa.tgz "$easy_rsa_url" 2>/dev/null || curl -Lo ~/easyrsa.tgz "$easy_rsa_url"
tar xzf ~/easyrsa.tgz -C ~/ tar xzf ~/easyrsa.tgz -C ~/
mv ~/EasyRSA-3.0.5/ /etc/openvpn/server/ mv ~/EasyRSA-3.0.5/ /etc/openvpn/server/
mv /etc/openvpn/server/EasyRSA-3.0.5/ /etc/openvpn/server/easy-rsa/ mv /etc/openvpn/server/EasyRSA-3.0.5/ /etc/openvpn/server/easy-rsa/
@ -255,14 +300,14 @@ LimitNPROC=infinity' > /etc/systemd/system/openvpn-server@server.service.d/disab
./easyrsa init-pki ./easyrsa init-pki
./easyrsa --batch build-ca nopass ./easyrsa --batch build-ca nopass
EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-server-full server nopass EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-server-full server nopass
EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-client-full $CLIENT nopass EASYRSA_CERT_EXPIRE=3650 ./easyrsa build-client-full "$client" nopass
EASYRSA_CRL_DAYS=3650 ./easyrsa gen-crl EASYRSA_CRL_DAYS=3650 ./easyrsa gen-crl
# Move the stuff we need # Move the stuff we need
cp pki/ca.crt pki/private/ca.key pki/issued/server.crt pki/private/server.key pki/crl.pem /etc/openvpn/server cp pki/ca.crt pki/private/ca.key pki/issued/server.crt pki/private/server.key pki/crl.pem /etc/openvpn/server
# CRL is read with each client connection, when OpenVPN is dropped to nobody # CRL is read with each client connection, when OpenVPN is dropped to nobody
chown nobody:$GROUPNAME /etc/openvpn/server/crl.pem chown nobody:"$group_name" /etc/openvpn/server/crl.pem
# Generate key for tls-auth # Generate key for tls-crypt
openvpn --genkey --secret /etc/openvpn/server/ta.key openvpn --genkey --secret /etc/openvpn/server/tc.key
# Create the DH parameters file using the predefined ffdhe2048 group # Create the DH parameters file using the predefined ffdhe2048 group
echo '-----BEGIN DH PARAMETERS----- echo '-----BEGIN DH PARAMETERS-----
MIIBCAKCAQEA//////////+t+FRYortKmq/cViAnPTzx2LnFg84tNpWp4TZBFGQz MIIBCAKCAQEA//////////+t+FRYortKmq/cViAnPTzx2LnFg84tNpWp4TZBFGQz
@ -273,33 +318,32 @@ YdEIqUuyyOP7uWrat2DX9GgdT0Kj3jlN9K5W7edjcrsZCwenyO4KbXCeAvzhzffi
ssbzSibBsu/6iGtCOGEoXJf//////////wIBAg== ssbzSibBsu/6iGtCOGEoXJf//////////wIBAg==
-----END DH PARAMETERS-----' > /etc/openvpn/server/dh.pem -----END DH PARAMETERS-----' > /etc/openvpn/server/dh.pem
# Generate server.conf # Generate server.conf
echo "port $PORT echo "local $ip
proto $PROTOCOL port $port
proto $protocol
dev tun dev tun
sndbuf 0
rcvbuf 0
ca ca.crt ca ca.crt
cert server.crt cert server.crt
key server.key key server.key
dh dh.pem dh dh.pem
auth SHA512 auth SHA512
tls-auth ta.key 0 tls-crypt tc.key
topology subnet topology subnet
server 10.8.0.0 255.255.255.0 server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt" > /etc/openvpn/server/server.conf ifconfig-pool-persist ipp.txt" > /etc/openvpn/server/server.conf
echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server/server.conf echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server/server.conf
# DNS # DNS
case $DNS in case "$dns" in
1) 1|"")
# Locate the proper resolv.conf # Locate the proper resolv.conf
# Needed for systems running systemd-resolved # Needed for systems running systemd-resolved
if grep -q "127.0.0.53" "/etc/resolv.conf"; then if grep -q "127.0.0.53" "/etc/resolv.conf"; then
RESOLVCONF='/run/systemd/resolve/resolv.conf' resolv_conf="/run/systemd/resolve/resolv.conf"
else else
RESOLVCONF='/etc/resolv.conf' resolv_conf="/etc/resolv.conf"
fi fi
# Obtain the resolvers from resolv.conf and use them for OpenVPN # Obtain the resolvers from resolv.conf and use them for OpenVPN
grep -v '#' $RESOLVCONF | grep 'nameserver' | grep -E -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | while read line; do grep -v '#' "$resolv_conf" | grep nameserver | grep -E -o '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | while read line; do
echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server/server.conf echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server/server.conf
done done
;; ;;
@ -323,12 +367,15 @@ ifconfig-pool-persist ipp.txt" > /etc/openvpn/server/server.conf
echo "keepalive 10 120 echo "keepalive 10 120
cipher AES-256-CBC cipher AES-256-CBC
user nobody user nobody
group $GROUPNAME group $group_name
persist-key persist-key
persist-tun persist-tun
status openvpn-status.log status openvpn-status.log
verb 3 verb 3
crl-verify crl.pem" >> /etc/openvpn/server/server.conf crl-verify crl.pem" >> /etc/openvpn/server/server.conf
if [[ "$protocol" = "udp" ]]; then
echo "explicit-exit-notify" >> /etc/openvpn/server/server.conf
fi
# Enable net.ipv4.ip_forward for the system # Enable net.ipv4.ip_forward for the system
echo 'net.ipv4.ip_forward=1' > /etc/sysctl.d/30-openvpn-forward.conf echo 'net.ipv4.ip_forward=1' > /etc/sysctl.d/30-openvpn-forward.conf
# Enable without waiting for a reboot or service restart # Enable without waiting for a reboot or service restart
@ -338,25 +385,25 @@ crl-verify crl.pem" >> /etc/openvpn/server/server.conf
# reload. # reload.
# We don't use --add-service=openvpn because that would only work with # We don't use --add-service=openvpn because that would only work with
# the default port and protocol. # the default port and protocol.
firewall-cmd --add-port=$PORT/$PROTOCOL firewall-cmd --add-port="$port"/"$protocol"
firewall-cmd --zone=trusted --add-source=10.8.0.0/24 firewall-cmd --zone=trusted --add-source=10.8.0.0/24
firewall-cmd --permanent --add-port=$PORT/$PROTOCOL firewall-cmd --permanent --add-port="$port"/"$protocol"
firewall-cmd --permanent --zone=trusted --add-source=10.8.0.0/24 firewall-cmd --permanent --zone=trusted --add-source=10.8.0.0/24
# Set NAT for the VPN subnet # Set NAT for the VPN subnet
firewall-cmd --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP firewall-cmd --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to "$ip"
firewall-cmd --permanent --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP firewall-cmd --permanent --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to "$ip"
else else
# Create a service to set up persistent iptables rules # Create a service to set up persistent iptables rules
echo "[Unit] echo "[Unit]
Before=network.target Before=network.target
[Service] [Service]
Type=oneshot Type=oneshot
ExecStart=/sbin/iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP ExecStart=/sbin/iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $ip
ExecStart=/sbin/iptables -I INPUT -p $PROTOCOL --dport $PORT -j ACCEPT ExecStart=/sbin/iptables -I INPUT -p $protocol --dport $port -j ACCEPT
ExecStart=/sbin/iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT ExecStart=/sbin/iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT
ExecStart=/sbin/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT ExecStart=/sbin/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
ExecStop=/sbin/iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP ExecStop=/sbin/iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $ip
ExecStop=/sbin/iptables -D INPUT -p $PROTOCOL --dport $PORT -j ACCEPT ExecStop=/sbin/iptables -D INPUT -p $protocol --dport $port -j ACCEPT
ExecStop=/sbin/iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT ExecStop=/sbin/iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT
ExecStop=/sbin/iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT ExecStop=/sbin/iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
RemainAfterExit=yes RemainAfterExit=yes
@ -365,7 +412,7 @@ WantedBy=multi-user.target" > /etc/systemd/system/openvpn-iptables.service
systemctl enable --now openvpn-iptables.service systemctl enable --now openvpn-iptables.service
fi fi
# If SELinux is enabled and a custom port was selected, we need this # If SELinux is enabled and a custom port was selected, we need this
if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$PORT" != '1194' ]]; then if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$port" != 1194 ]]; then
# Install semanage if not already present # Install semanage if not already present
if ! hash semanage 2>/dev/null; then if ! hash semanage 2>/dev/null; then
if grep -qs "CentOS Linux release 7" "/etc/centos-release"; then if grep -qs "CentOS Linux release 7" "/etc/centos-release"; then
@ -374,21 +421,17 @@ WantedBy=multi-user.target" > /etc/systemd/system/openvpn-iptables.service
yum install policycoreutils-python-utils -y yum install policycoreutils-python-utils -y
fi fi
fi fi
semanage port -a -t openvpn_port_t -p $PROTOCOL $PORT semanage port -a -t openvpn_port_t -p "$protocol" "$port"
fi fi
# And finally, enable and start the OpenVPN service
systemctl enable --now openvpn-server@server.service
# If the server is behind a NAT, use the correct IP address # If the server is behind a NAT, use the correct IP address
if [[ "$PUBLICIP" != "" ]]; then if [[ "$public_ip" != "" ]]; then
IP=$PUBLICIP ip="$public_ip"
fi fi
# client-common.txt is created so we have a template to add further users later # client-common.txt is created so we have a template to add further users later
echo "client echo "client
dev tun dev tun
proto $PROTOCOL proto $protocol
sndbuf 0 remote $ip $port
rcvbuf 0
remote $IP $PORT
resolv-retry infinite resolv-retry infinite
nobind nobind
persist-key persist-key
@ -396,14 +439,16 @@ persist-tun
remote-cert-tls server remote-cert-tls server
auth SHA512 auth SHA512
cipher AES-256-CBC cipher AES-256-CBC
setenv opt block-outside-dns ignore-unknown-option block-outside-dns
key-direction 1 block-outside-dns
verb 3" > /etc/openvpn/server/client-common.txt verb 3" > /etc/openvpn/server/client-common.txt
# Enable and start the OpenVPN service
systemctl enable --now openvpn-server@server.service
# Generates the custom client.ovpn # Generates the custom client.ovpn
newclient "$CLIENT" new_client "$client"
echo echo
echo "Finished!" echo "Finished!"
echo echo
echo "Your client configuration is available at:" ~/"$CLIENT.ovpn" echo "Your client configuration is available at:" ~/"$client.ovpn"
echo "If you want to add more clients, you simply need to run this script again!" echo "If you want to add more clients, just run this script again!"
fi fi