setup-ipsec-vpn/extras/add_vpn_user.sh

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#!/bin/bash
#
# Script to add/update a VPN user for both IPsec/L2TP and Cisco IPsec
#
# Copyright (C) 2018-2024 Lin Song <linsongui@gmail.com>
#
# 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"
SYS_DT=$(date +%F-%T | tr ':' '_')
exiterr() { echo "Error: $1" >&2; exit 1; }
conf_bk() { /bin/cp -f "$1" "$1.old-$SYS_DT" 2>/dev/null; }
show_intro() {
cat <<'EOF'
Welcome! Use this script to add or update a VPN user account for both
IPsec/L2TP and IPsec/XAuth ("Cisco IPsec") modes.
If the username you specify already exists, it will be updated
with the new password. Otherwise, a new VPN user will be added.
EOF
}
add_vpn_user() {
if [ "$(id -u)" != 0 ]; then
exiterr "Script must be run as root. Try 'sudo bash $0'"
fi
if ! grep -qs "hwdsl2 VPN script" /etc/sysctl.conf \
|| [ ! -f /etc/ppp/chap-secrets ] || [ ! -f /etc/ipsec.d/passwd ]; then
cat 1>&2 <<'EOF'
Error: Your must first set up the IPsec VPN server before adding VPN users.
See: https://github.com/hwdsl2/setup-ipsec-vpn
EOF
exit 1
fi
command -v openssl >/dev/null 2>&1 || exiterr "'openssl' not found. Abort."
if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
cat 1>&2 <<EOF
Usage: sudo bash $0 'username_to_add' 'password'
sudo bash $0 'username_to_update' 'new_password'
You may also run this script interactively without arguments.
EOF
exit 1
fi
VPN_USER=$1
VPN_PASSWORD=$2
if [ -z "$VPN_USER" ] || [ -z "$VPN_PASSWORD" ]; then
show_intro
echo
echo "List of existing VPN usernames:"
cut -f1 -d : /etc/ipsec.d/passwd | LC_ALL=C sort
echo
echo "Enter the VPN username you want to add or update."
read -rp "Username: " VPN_USER
if [ -z "$VPN_USER" ]; then
echo "Abort. No changes were made." >&2
exit 1
fi
read -rp "Password: " VPN_PASSWORD
if [ -z "$VPN_PASSWORD" ]; then
echo "Abort. No changes were made." >&2
exit 1
fi
fi
if printf '%s' "$VPN_USER $VPN_PASSWORD" | LC_ALL=C grep -q '[^ -~]\+'; then
exiterr "VPN credentials must not contain non-ASCII characters."
fi
case "$VPN_USER $VPN_PASSWORD" in
*[\\\"\']*)
exiterr "VPN credentials must not contain these special characters: \\ \" '"
;;
esac
if [ -n "$1" ] && [ -n "$2" ]; then
show_intro
fi
cat <<EOF
================================================
VPN user to add or update:
Username: $VPN_USER
Password: $VPN_PASSWORD
Write these down. You'll need them to connect!
VPN client setup: https://vpnsetup.net/clients
================================================
EOF
printf "Do you want to continue? [Y/n] "
read -r response
case $response in
[yY][eE][sS]|[yY]|'')
echo
echo "Adding or updating VPN user..."
echo
;;
*)
echo "Abort. No changes were made."
exit 1
;;
esac
# Backup config files
conf_bk "/etc/ppp/chap-secrets"
conf_bk "/etc/ipsec.d/passwd"
# Add or update VPN user
sed -i "/^\"$VPN_USER\" /d" /etc/ppp/chap-secrets
cat >> /etc/ppp/chap-secrets <<EOF
"$VPN_USER" l2tpd "$VPN_PASSWORD" *
EOF
# shellcheck disable=SC2016
sed -i '/^'"$VPN_USER"':\$1\$/d' /etc/ipsec.d/passwd
VPN_PASSWORD_ENC=$(openssl passwd -1 "$VPN_PASSWORD")
cat >> /etc/ipsec.d/passwd <<EOF
$VPN_USER:$VPN_PASSWORD_ENC:xauth-psk
EOF
# Update file attributes
chmod 600 /etc/ppp/chap-secrets* /etc/ipsec.d/passwd*
cat <<'EOF'
Done!
Note: All VPN users will share the same IPsec PSK.
If you forgot the PSK, check /etc/ipsec.secrets.
EOF
}
## Defer until we have the complete script
add_vpn_user "$@"
exit 0