#!/bin/bash # # Script for automatic setup of an IPsec VPN server on Amazon Linux 2 # # DO NOT RUN THIS SCRIPT ON YOUR PC OR MAC! # # The latest version of this script is available at: # https://github.com/hwdsl2/setup-ipsec-vpn # # Copyright (C) 2020-2023 Lin Song # # 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! # ===================================================== # Define your own values for these variables # - IPsec pre-shared key, VPN username and password # - All values MUST be placed inside 'single quotes' # - DO NOT use these special characters within values: \ " ' YOUR_IPSEC_PSK='' YOUR_USERNAME='' YOUR_PASSWORD='' # ===================================================== export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" SYS_DT=$(date +%F-%T | tr ':' '_') exiterr() { echo "Error: $1" >&2; exit 1; } exiterr2() { exiterr "'yum install' failed."; } conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; } bigecho() { echo "## $1"; } check_ip() { IP_REGEX='^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$' printf '%s' "$1" | tr -d '\n' | grep -Eq "$IP_REGEX" } check_dns_name() { FQDN_REGEX='^([a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}$' printf '%s' "$1" | tr -d '\n' | grep -Eq "$FQDN_REGEX" } check_root() { if [ "$(id -u)" != 0 ]; then exiterr "Script must be run as root. Try 'sudo bash $0'" fi } check_os() { if ! grep -qs "Amazon Linux release 2 " /etc/system-release; then exiterr "This script only supports Amazon Linux 2." fi } check_iface() { def_iface=$(route 2>/dev/null | grep -m 1 '^default' | grep -o '[^ ]*$') [ -z "$def_iface" ] && def_iface=$(ip -4 route list 0/0 2>/dev/null | grep -m 1 -Po '(?<=dev )(\S+)') def_state=$(cat "/sys/class/net/$def_iface/operstate" 2>/dev/null) if [ -n "$def_state" ] && [ "$def_state" != "down" ]; then case $def_iface in wl*) exiterr "Wireless interface '$def_iface' detected. DO NOT run this script on your PC or Mac!" ;; esac NET_IFACE="$def_iface" else eth0_state=$(cat "/sys/class/net/eth0/operstate" 2>/dev/null) if [ -z "$eth0_state" ] || [ "$eth0_state" = "down" ]; then exiterr "Could not detect the default network interface." fi NET_IFACE=eth0 fi } check_creds() { [ -n "$YOUR_IPSEC_PSK" ] && VPN_IPSEC_PSK="$YOUR_IPSEC_PSK" [ -n "$YOUR_USERNAME" ] && VPN_USER="$YOUR_USERNAME" [ -n "$YOUR_PASSWORD" ] && VPN_PASSWORD="$YOUR_PASSWORD" if [ -z "$VPN_IPSEC_PSK" ] && [ -z "$VPN_USER" ] && [ -z "$VPN_PASSWORD" ]; then bigecho "VPN credentials not set by user. Generating random PSK and password..." VPN_IPSEC_PSK=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' /dev/null | head -c 20) VPN_USER=vpnuser VPN_PASSWORD=$(LC_CTYPE=C tr -dc 'A-HJ-NPR-Za-km-z2-9' /dev/null | head -c 16) fi if [ -z "$VPN_IPSEC_PSK" ] || [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then exiterr "All VPN credentials must be specified. Edit the script and re-enter them." fi if printf '%s' "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" | LC_ALL=C grep -q '[^ -~]\+'; then exiterr "VPN credentials must not contain non-ASCII characters." fi case "$VPN_IPSEC_PSK $VPN_USER $VPN_PASSWORD" in *[\\\"\']*) exiterr "VPN credentials must not contain these special characters: \\ \" '" ;; esac } check_dns() { if { [ -n "$VPN_DNS_SRV1" ] && ! check_ip "$VPN_DNS_SRV1"; } \ || { [ -n "$VPN_DNS_SRV2" ] && ! check_ip "$VPN_DNS_SRV2"; }; then exiterr "The DNS server specified is invalid." fi } check_server_dns() { if [ -n "$VPN_DNS_NAME" ] && ! check_dns_name "$VPN_DNS_NAME"; then exiterr "Invalid DNS name. 'VPN_DNS_NAME' must be a fully qualified domain name (FQDN)." fi } check_client_name() { if [ -n "$VPN_CLIENT_NAME" ]; then name_len="$(printf '%s' "$VPN_CLIENT_NAME" | wc -m)" if [ "$name_len" -gt "64" ] || printf '%s' "$VPN_CLIENT_NAME" | LC_ALL=C grep -q '[^A-Za-z0-9_-]\+' \ || case $VPN_CLIENT_NAME in -*) true ;; *) false ;; esac; then exiterr "Invalid client name. Use one word only, no special characters except '-' and '_'." fi fi } check_subnets() { if [ -s /etc/ipsec.conf ] && grep -qs "hwdsl2 VPN script" /etc/sysctl.conf; then L2TP_NET=${VPN_L2TP_NET:-'192.168.42.0/24'} XAUTH_NET=${VPN_XAUTH_NET:-'192.168.43.0/24'} if ! grep -q "$L2TP_NET" /etc/ipsec.conf \ || ! grep -q "$XAUTH_NET" /etc/ipsec.conf; then echo "Error: The custom VPN subnets specified do not match initial install." >&2 echo " See Advanced usage -> Customize VPN subnets for more information." >&2 exit 1 fi fi } start_setup() { bigecho "VPN setup in progress... Please be patient." mkdir -p /opt/src cd /opt/src || exit 1 } install_setup_pkgs() { bigecho "Installing packages required for setup..." ( set -x yum -y -q install wget bind-utils openssl tar \ iptables iproute gawk grep sed net-tools >/dev/null ) || exiterr2 } get_default_ip() { def_ip=$(ip -4 route get 1 | sed 's/ uid .*//' | awk '{print $NF;exit}' 2>/dev/null) if check_ip "$def_ip" \ && ! printf '%s' "$def_ip" | grep -Eq '^(10|127|172\.(1[6-9]|2[0-9]|3[0-1])|192\.168|169\.254)\.'; then public_ip="$def_ip" fi } detect_ip() { public_ip=${VPN_PUBLIC_IP:-''} check_ip "$public_ip" || get_default_ip check_ip "$public_ip" && return 0 bigecho "Trying to auto discover IP of this server..." check_ip "$public_ip" || public_ip=$(dig @resolver1.opendns.com -t A -4 myip.opendns.com +short) check_ip "$public_ip" || public_ip=$(wget -t 2 -T 10 -qO- http://ipv4.icanhazip.com) check_ip "$public_ip" || public_ip=$(wget -t 2 -T 10 -qO- http://ip1.dynupdate.no-ip.com) check_ip "$public_ip" || exiterr "Cannot detect this server's public IP. Define it as variable 'VPN_PUBLIC_IP' and re-run this script." } add_epel_repo() { bigecho "Adding the EPEL repository..." ( set -x amazon-linux-extras install epel -y >/dev/null ) || exiterr2 } install_vpn_pkgs_1() { bigecho "Installing packages required for the VPN..." ( set -x yum -y -q install nss-devel nspr-devel pkgconfig pam-devel \ libcap-ng-devel libselinux-devel curl-devel nss-tools \ flex bison gcc make util-linux ppp \ systemd-devel iptables-services \ libevent-devel fipscheck-devel >/dev/null ) || exiterr2 } install_vpn_pkgs_2() { ( set -x yum --enablerepo=epel -y -q install xl2tpd >/dev/null 2>&1 ) || exiterr2 } create_f2b_config() { F2B_FILE=/etc/fail2ban/jail.local if [ ! -f "$F2B_FILE" ]; then bigecho "Creating basic Fail2Ban rules..." cat > "$F2B_FILE" <<'EOF' [ssh-iptables] enabled = true filter = sshd logpath = /var/log/secure action = iptables[name=SSH, port=ssh, protocol=tcp] EOF fi } install_fail2ban() { bigecho "Installing Fail2Ban to protect SSH..." ( set -x yum --enablerepo=epel -y -q install fail2ban >/dev/null ) && create_f2b_config } link_scripts() { cd /opt/src || exit 1 /bin/mv -f ikev2setup.sh ikev2.sh /bin/mv -f add_vpn_user.sh addvpnuser.sh /bin/mv -f del_vpn_user.sh delvpnuser.sh echo "+ ikev2.sh addvpnuser.sh delvpnuser.sh" for sc in ikev2.sh addvpnuser.sh delvpnuser.sh; do [ -s "$sc" ] && chmod +x "$sc" && ln -s "/opt/src/$sc" /usr/bin 2>/dev/null done } get_helper_scripts() { bigecho "Downloading helper scripts..." base1="https://raw.githubusercontent.com/hwdsl2/setup-ipsec-vpn/master/extras" base2="https://gitlab.com/hwdsl2/setup-ipsec-vpn/-/raw/master/extras" sc1=ikev2setup.sh sc2=add_vpn_user.sh sc3=del_vpn_user.sh cd /opt/src || exit 1 /bin/rm -f "$sc1" "$sc2" "$sc3" if wget -t 3 -T 30 -q "$base1/$sc1" "$base1/$sc2" "$base1/$sc3"; then link_scripts else /bin/rm -f "$sc1" "$sc2" "$sc3" if wget -t 3 -T 30 -q "$base2/$sc1" "$base2/$sc2" "$base2/$sc3"; then link_scripts else echo "Warning: Could not download helper scripts." >&2 /bin/rm -f "$sc1" "$sc2" "$sc3" fi fi } get_swan_ver() { SWAN_VER=4.11 base_url="https://github.com/hwdsl2/vpn-extras/releases/download/v1.0.0" swan_ver_url="$base_url/v1-amzn-2-swanver" swan_ver_latest=$(wget -t 2 -T 10 -qO- "$swan_ver_url" | head -n 1) [ -z "$swan_ver_latest" ] && swan_ver_latest=$(curl -m 10 -fsL "$swan_ver_url" 2>/dev/null | head -n 1) if printf '%s' "$swan_ver_latest" | grep -Eq '^([3-9]|[1-9][0-9]{1,2})(\.([0-9]|[1-9][0-9]{1,2})){1,2}$'; then SWAN_VER="$swan_ver_latest" fi } check_libreswan() { check_result=0 ipsec_ver=$(/usr/local/sbin/ipsec --version 2>/dev/null) swan_ver_old=$(printf '%s' "$ipsec_ver" | sed -e 's/.*Libreswan U\?//' -e 's/\( (\|\/K\).*//') ipsec_bin="/usr/local/sbin/ipsec" if [ -n "$swan_ver_old" ] && printf '%s' "$ipsec_ver" | grep -qi 'libreswan' \ && [ "$(find "$ipsec_bin" -mmin -10080)" ]; then check_result=1 return 0 fi get_swan_ver if [ -s "$ipsec_bin" ] && [ "$swan_ver_old" = "$SWAN_VER" ]; then touch "$ipsec_bin" fi [ "$swan_ver_old" = "$SWAN_VER" ] && check_result=1 } get_libreswan() { if [ "$check_result" = 0 ]; then bigecho "Downloading Libreswan..." cd /opt/src || exit 1 swan_file="libreswan-$SWAN_VER.tar.gz" swan_url1="https://github.com/libreswan/libreswan/archive/v$SWAN_VER.tar.gz" swan_url2="https://download.libreswan.org/$swan_file" ( set -x wget -t 3 -T 30 -q -O "$swan_file" "$swan_url1" || wget -t 3 -T 30 -q -O "$swan_file" "$swan_url2" ) || exit 1 /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" tar xzf "$swan_file" && /bin/rm -f "$swan_file" else bigecho "Libreswan $swan_ver_old is already installed, skipping..." fi } install_libreswan() { if [ "$check_result" = 0 ]; then bigecho "Compiling and installing Libreswan, please wait..." cd "libreswan-$SWAN_VER" || exit 1 cat > Makefile.inc.local <<'EOF' WERROR_CFLAGS=-w -s USE_DNSSEC=false USE_DH2=true USE_NSS_KDF=false USE_LINUX_AUDIT=false USE_SECCOMP=false FINALNSSDIR=/etc/ipsec.d EOF if ! grep -qs IFLA_XFRM_LINK /usr/include/linux/if_link.h; then echo "USE_XFRM_INTERFACE_IFLA_HEADER=true" >> Makefile.inc.local fi NPROCS=$(grep -c ^processor /proc/cpuinfo) [ -z "$NPROCS" ] && NPROCS=1 ( set -x make "-j$((NPROCS+1))" -s base >/dev/null && make -s install-base >/dev/null ) cd /opt/src || exit 1 /bin/rm -rf "/opt/src/libreswan-$SWAN_VER" if ! /usr/local/sbin/ipsec --version 2>/dev/null | grep -qF "$SWAN_VER"; then exiterr "Libreswan $SWAN_VER failed to build." fi fi } create_vpn_config() { bigecho "Creating VPN configuration..." L2TP_NET=${VPN_L2TP_NET:-'192.168.42.0/24'} L2TP_LOCAL=${VPN_L2TP_LOCAL:-'192.168.42.1'} L2TP_POOL=${VPN_L2TP_POOL:-'192.168.42.10-192.168.42.250'} XAUTH_NET=${VPN_XAUTH_NET:-'192.168.43.0/24'} XAUTH_POOL=${VPN_XAUTH_POOL:-'192.168.43.10-192.168.43.250'} DNS_SRV1=${VPN_DNS_SRV1:-'8.8.8.8'} DNS_SRV2=${VPN_DNS_SRV2:-'8.8.4.4'} DNS_SRVS="\"$DNS_SRV1 $DNS_SRV2\"" [ -n "$VPN_DNS_SRV1" ] && [ -z "$VPN_DNS_SRV2" ] && DNS_SRVS="$DNS_SRV1" # Create IPsec config conf_bk "/etc/ipsec.conf" cat > /etc/ipsec.conf < /etc/ipsec.secrets < /etc/xl2tpd/xl2tpd.conf < /etc/ppp/options.xl2tpd <> /etc/ppp/options.xl2tpd < /etc/ppp/chap-secrets < /etc/ipsec.d/passwd <> /etc/sysctl.conf </dev/null 2>&1 iptables-save > "$IPT_FILE.old-$SYS_DT" $ipi 1 -p udp --dport 1701 -m policy --dir in --pol none -j DROP $ipi 2 -m conntrack --ctstate INVALID -j DROP $ipi 3 -m conntrack --ctstate "$res" -j ACCEPT $ipi 4 -p udp -m multiport --dports 500,4500 -j ACCEPT $ipi 5 -p udp --dport 1701 -m policy --dir in --pol ipsec -j ACCEPT $ipi 6 -p udp --dport 1701 -j DROP $ipf 1 -m conntrack --ctstate INVALID -j DROP $ipf 2 -i "$NET_IFACE" -o ppp+ -m conntrack --ctstate "$res" -j ACCEPT $ipf 3 -i ppp+ -o "$NET_IFACE" -j ACCEPT $ipf 4 -i ppp+ -o ppp+ -j ACCEPT $ipf 5 -i "$NET_IFACE" -d "$XAUTH_NET" -m conntrack --ctstate "$res" -j ACCEPT $ipf 6 -s "$XAUTH_NET" -o "$NET_IFACE" -j ACCEPT $ipf 7 -s "$XAUTH_NET" -o ppp+ -j ACCEPT iptables -A FORWARD -j DROP $ipp -s "$XAUTH_NET" -o "$NET_IFACE" -m policy --dir out --pol none -j MASQUERADE $ipp -s "$L2TP_NET" -o "$NET_IFACE" -j MASQUERADE echo "# Modified by hwdsl2 VPN script" > "$IPT_FILE" iptables-save >> "$IPT_FILE" fi } enable_on_boot() { bigecho "Enabling services on boot..." systemctl --now mask firewalld 2>/dev/null systemctl enable iptables 2>/dev/null systemctl enable fail2ban 2>/dev/null if ! grep -qs "hwdsl2 VPN script" /etc/rc.local; then if [ -f /etc/rc.local ]; then conf_bk "/etc/rc.local" else echo '#!/bin/sh' > /etc/rc.local fi cat >> /etc/rc.local <<'EOF' # Added by hwdsl2 VPN script (sleep 15 service ipsec restart service xl2tpd restart echo 1 > /proc/sys/net/ipv4/ip_forward)& EOF fi } start_services() { bigecho "Starting services..." sysctl -e -q -p chmod +x /etc/rc.local chmod 600 /etc/ipsec.secrets* /etc/ppp/chap-secrets* /etc/ipsec.d/passwd* restorecon /etc/ipsec.d/*db 2>/dev/null restorecon /usr/local/sbin -Rv 2>/dev/null restorecon /usr/local/libexec/ipsec -Rv 2>/dev/null iptables-restore < "$IPT_FILE" # Fix xl2tpd if l2tp_ppp is unavailable if ! modprobe -q l2tp_ppp; then sed -i '/^ExecStartPre=\//s/=/=-/' /usr/lib/systemd/system/xl2tpd.service systemctl daemon-reload fi mkdir -p /run/pluto service fail2ban restart 2>/dev/null service ipsec restart 2>/dev/null service xl2tpd restart 2>/dev/null } show_vpn_info() { cat <