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docker-ipsec-vpn-server/run.sh
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2017-01-16 22:17:21 -06:00

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#!/bin/sh
#
# Docker script to configure and start an IPsec VPN server
#
# DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! THIS IS ONLY MEANT TO BE RUN
# IN A DOCKER CONTAINER!
#
# Copyright (C) 2016-2017 Lin Song <linsongui@gmail.com>
# Based on the work of Thomas Sarlandie (Copyright 2012)
#
# This work is licensed under the Creative Commons Attribution-ShareAlike 3.0
# Unported License: http://creativecommons.org/licenses/by-sa/3.0/
#
# Attribution required: please include my name in any derivative and let me
# know how you have improved it!
export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
exiterr() { echo "Error: $1" >&2; exit 1; }
check_ip() {
IP_REGEX="^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$"
printf %s "$1" | tr -d '\n' | grep -Eq "$IP_REGEX"
}
if [ ! -f "/.dockerenv" ]; then
exiterr "This script ONLY runs in a Docker container."
fi
mkdir -p /opt/src
vpn_env="/opt/src/vpn-gen.env"
if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then
if [ -f "$vpn_env" ]; then
echo
echo "Retrieving previously generated VPN credentials..."
. "$vpn_env"
else
echo
echo "VPN credentials not set by user. Generating random PSK and password..."
VPN_IPSEC_PSK="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)"
VPN_USER=vpnuser
VPN_PASSWORD="$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' < /dev/urandom | head -c 16)"
echo "VPN_IPSEC_PSK=$VPN_IPSEC_PSK" > "$vpn_env"
echo "VPN_USER=$VPN_USER" >> "$vpn_env"
echo "VPN_PASSWORD=$VPN_PASSWORD" >> "$vpn_env"
chmod 600 "$vpn_env"
fi
fi
if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then
exiterr "All VPN credentials must be specified. Edit your 'env' file and re-enter them."
fi
case "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" in
*[\\\"\']*)
exiterr "VPN credentials must not contain any of these characters: \\ \" '"
;;
esac
echo
echo 'Trying to auto discover IPs of this server...'
# In case auto IP discovery fails, you may manually enter the public IP
# of this server in your 'env' file, using variable 'VPN_PUBLIC_IP'.
PUBLIC_IP=${VPN_PUBLIC_IP:-''}
# Try to auto discover IPs of this server
[ -z "$PUBLIC_IP" ] && PUBLIC_IP=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short)
PRIVATE_IP=$(ip -4 route get 1 | awk '{print $NF;exit}')
# Check IPs for correct format
check_ip "$PUBLIC_IP" || PUBLIC_IP=$(wget -t 3 -T 15 -qO- http://ipv4.icanhazip.com)
check_ip "$PUBLIC_IP" || exiterr "Cannot find valid public IP. Define it in your 'env' file as 'VPN_PUBLIC_IP'."
check_ip "$PRIVATE_IP" || PRIVATE_IP=$(ifconfig eth0 | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*')
check_ip "$PRIVATE_IP" || exiterr "Cannot find valid private IP."
# Create IPsec (Libreswan) config
cat > /etc/ipsec.conf <<EOF
version 2.0
config setup
virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:!192.168.42.0/23
protostack=netkey
nhelpers=0
interfaces=%defaultroute
uniqueids=no
conn shared
left=$PRIVATE_IP
leftid=$PUBLIC_IP
right=%any
encapsulation=yes
authby=secret
pfs=no
rekey=no
keyingtries=5
dpddelay=30
dpdtimeout=120
dpdaction=clear
ike=3des-sha1,aes-sha1,aes256-sha2_512,aes256-sha2_256
phase2alg=3des-sha1,aes-sha1,aes256-sha2_512,aes256-sha2_256
sha2-truncbug=yes
conn l2tp-psk
auto=add
leftsubnet=$PRIVATE_IP/32
leftnexthop=%defaultroute
leftprotoport=17/1701
rightprotoport=17/%any
type=transport
phase2=esp
also=shared
conn xauth-psk
auto=add
leftsubnet=0.0.0.0/0
rightaddresspool=192.168.43.10-192.168.43.250
modecfgdns1=8.8.8.8
modecfgdns2=8.8.4.4
leftxauthserver=yes
rightxauthclient=yes
leftmodecfgserver=yes
rightmodecfgclient=yes
modecfgpull=yes
xauthby=file
ike-frag=yes
ikev2=never
cisco-unity=yes
also=shared
EOF
# Specify IPsec PSK
cat > /etc/ipsec.secrets <<EOF
$PUBLIC_IP %any : PSK "$VPN_IPSEC_PSK"
EOF
# Create xl2tpd config
cat > /etc/xl2tpd/xl2tpd.conf <<'EOF'
[global]
port = 1701
[lns default]
ip range = 192.168.42.10-192.168.42.250
local ip = 192.168.42.1
require chap = yes
refuse pap = yes
require authentication = yes
name = l2tpd
pppoptfile = /etc/ppp/options.xl2tpd
length bit = yes
EOF
# Set xl2tpd options
cat > /etc/ppp/options.xl2tpd <<'EOF'
ipcp-accept-local
ipcp-accept-remote
ms-dns 8.8.8.8
ms-dns 8.8.4.4
noccp
auth
mtu 1280
mru 1280
proxyarp
lcp-echo-failure 4
lcp-echo-interval 30
connect-delay 5000
EOF
# Create VPN credentials
cat > /etc/ppp/chap-secrets <<EOF
# Secrets for authentication using CHAP
# client server secret IP addresses
"$VPN_USER" l2tpd "$VPN_PASSWORD" *
EOF
VPN_PASSWORD_ENC=$(openssl passwd -1 "$VPN_PASSWORD")
cat > /etc/ipsec.d/passwd <<EOF
$VPN_USER:$VPN_PASSWORD_ENC:xauth-psk
EOF
# Update sysctl settings
SYST='/sbin/sysctl -e -q -w'
$SYST kernel.msgmnb=65536
$SYST kernel.msgmax=65536
$SYST kernel.shmmax=68719476736
$SYST kernel.shmall=4294967296
$SYST net.ipv4.ip_forward=1
$SYST net.ipv4.tcp_syncookies=1
$SYST net.ipv4.conf.all.accept_source_route=0
$SYST net.ipv4.conf.default.accept_source_route=0
$SYST net.ipv4.conf.all.accept_redirects=0
$SYST net.ipv4.conf.default.accept_redirects=0
$SYST net.ipv4.conf.all.send_redirects=0
$SYST net.ipv4.conf.default.send_redirects=0
$SYST net.ipv4.conf.lo.send_redirects=0
$SYST net.ipv4.conf.eth0.send_redirects=0
$SYST net.ipv4.conf.all.rp_filter=0
$SYST net.ipv4.conf.default.rp_filter=0
$SYST net.ipv4.conf.lo.rp_filter=0
$SYST net.ipv4.conf.eth0.rp_filter=0
$SYST net.ipv4.icmp_echo_ignore_broadcasts=1
$SYST net.ipv4.icmp_ignore_bogus_error_responses=1
$SYST net.core.wmem_max=12582912
$SYST net.core.rmem_max=12582912
$SYST net.ipv4.tcp_rmem="10240 87380 12582912"
$SYST net.ipv4.tcp_wmem="10240 87380 12582912"
# Create IPTables rules
iptables -I INPUT 1 -m conntrack --ctstate INVALID -j DROP
iptables -I INPUT 2 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -I INPUT 3 -p udp -m multiport --dports 500,4500 -j ACCEPT
iptables -I INPUT 4 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT
iptables -I INPUT 5 -p udp --dport 1701 -j DROP
iptables -I FORWARD 1 -m conntrack --ctstate INVALID -j DROP
iptables -I FORWARD 2 -i eth+ -o ppp+ -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -I FORWARD 3 -i ppp+ -o eth+ -j ACCEPT
iptables -I FORWARD 4 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j ACCEPT
iptables -I FORWARD 5 -i eth+ -d 192.168.43.0/24 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -I FORWARD 6 -s 192.168.43.0/24 -o eth+ -j ACCEPT
# Uncomment if you wish to disallow traffic between VPN clients themselves
# iptables -I FORWARD 2 -i ppp+ -o ppp+ -s 192.168.42.0/24 -d 192.168.42.0/24 -j DROP
# iptables -I FORWARD 3 -s 192.168.43.0/24 -d 192.168.43.0/24 -j DROP
iptables -A FORWARD -j DROP
iptables -t nat -I POSTROUTING -s 192.168.43.0/24 -o eth+ -m policy --dir out --pol none -j SNAT --to-source "$PRIVATE_IP"
iptables -t nat -I POSTROUTING -s 192.168.42.0/24 -o eth+ -j SNAT --to-source "$PRIVATE_IP"
# Update file attributes
chmod 600 /etc/ipsec.secrets /etc/ppp/chap-secrets /etc/ipsec.d/passwd
cat <<EOF
================================================
IPsec VPN server is now ready for use!
Connect to your new VPN with these details:
Server IP: $PUBLIC_IP
IPsec PSK: $VPN_IPSEC_PSK
Username: $VPN_USER
Password: $VPN_PASSWORD
Write these down. You'll need them to connect!
Setup VPN clients: https://git.io/vpnclients
================================================
EOF
# Load IPsec NETKEY kernel module
modprobe af_key
# Start services
mkdir -p /var/run/pluto /var/run/xl2tpd
rm -f /var/run/pluto/pluto.pid /var/run/xl2tpd.pid
/usr/local/sbin/ipsec start --config /etc/ipsec.conf
exec /usr/sbin/xl2tpd -D -c /etc/xl2tpd/xl2tpd.conf