#!/bin/bash # OpenVPN road warrior installer for Debian-based distros # This script will only work on Debian-based systems. It isn't bulletproof but # it will probably work if you simply want to setup a VPN on your Debian/Ubuntu # VPS. It has been designed to be as unobtrusive and universal as possible. if [[ "$USER" != 'root' ]]; then echo "Sorry, you need to run this as root" exit fi if [[ ! -e /dev/net/tun ]]; then echo "TUN/TAP is not available" exit fi if [[ ! -e /etc/debian_version ]]; then echo "Looks like you aren't running this installer on a Debian-based system" exit fi newclient () { # Generates the client config bundle mkdir ~/ovpn-$1 cd ~/ovpn-$1 cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf ./$1.conf cp /etc/openvpn/easy-rsa/2.0/keys/ca.crt /etc/openvpn/easy-rsa/2.0/keys/$1.crt /etc/openvpn/easy-rsa/2.0/keys/$1.key ./ sed -i "s|cert client.crt|cert $1.crt|" $1.conf sed -i "s|key client.key|key $1.key|" $1.conf tar -czf ../ovpn-$1.tar.gz $1.conf ca.crt $1.crt $1.key cd ~/ rm -rf ovpn-$1 } # Try to get our IP from the system and fallback to the Internet. # I do this to make the script compatible with NATed servers (lowendspirit.com) # and to avoid getting an IPv6. IP=$(ifconfig | grep 'inet addr:' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | cut -d: -f2 | awk '{ print $1}' | head -1) if [[ "$IP" = "" ]]; then IP=$(wget -qO- ipv4.icanhazip.com) fi if [[ -e /etc/openvpn/server.conf ]]; then while : do clear echo "Looks like OpenVPN is already installed" echo "What do you want to do?" echo "" echo "1) Add a cert for a new user" echo "2) Revoke existing user cert" echo "3) Remove OpenVPN" echo "4) Exit" echo "" read -p "Select an option [1-4]: " option case $option in 1) echo "" echo "Tell me a name for the client cert" echo "Please, use one word only, no special characters" read -p "Client name: " -e -i client CLIENT cd /etc/openvpn/easy-rsa/2.0/ source ./vars # build-key for the client export KEY_CN="$CLIENT" export EASY_RSA="${EASY_RSA:-.}" "$EASY_RSA/pkitool" $CLIENT # Generate the client config bundle newclient "$CLIENT" echo "" echo "Client $CLIENT added, certs available at ~/ovpn-$CLIENT.tar.gz" exit ;; 2) echo "" echo "Tell me the existing client name" read -p "Client name: " -e -i client CLIENT cd /etc/openvpn/easy-rsa/2.0/ . /etc/openvpn/easy-rsa/2.0/vars . /etc/openvpn/easy-rsa/2.0/revoke-full $CLIENT # If it's the first time revoking a cert, we need to add the crl-verify line if grep -q "crl-verify" "/etc/openvpn/server.conf"; then echo "" echo "Certificate for client $CLIENT revoked" else echo "crl-verify /etc/openvpn/easy-rsa/2.0/keys/crl.pem" >> "/etc/openvpn/server.conf" /etc/init.d/openvpn restart echo "" echo "Certificate for client $CLIENT revoked" fi exit ;; 3) apt-get remove --purge -y openvpn openvpn-blacklist rm -rf /etc/openvpn rm -rf /usr/share/doc/openvpn sed -i '/--dport 53 -j REDIRECT --to-port/d' /etc/rc.local sed -i '/iptables -t nat -A POSTROUTING -s 10.8.0.0/d' /etc/rc.local echo "" echo "OpenVPN removed!" exit ;; 4) exit;; esac done else echo 'Welcome to this quick OpenVPN "road warrior" installer' echo "" # OpenVPN setup and first user creation echo "I need to ask you a few questions before starting the setup" echo "You can leave the default options and just press enter if you are ok with them" echo "" echo "First I need to know the IPv4 address of the network interface you want OpenVPN" echo "listening to." read -p "IP address: " -e -i $IP IP echo "" echo "What port do you want for OpenVPN?" read -p "Port: " -e -i 1194 PORT echo "" echo "Do you want OpenVPN to be available at port 53 too?" echo "This can be useful to connect under restrictive networks" read -p "Listen at port 53 [y/n]: " -e -i n ALTPORT echo "" echo "Finally, tell me your name for the client cert" echo "Please, use one word only, no special characters" read -p "Client name: " -e -i client CLIENT echo "" echo "Okay, that was all I needed. We are ready to setup your OpenVPN server now" read -n1 -r -p "Press any key to continue..." apt-get update apt-get install openvpn iptables openssl -y cp -R /usr/share/doc/openvpn/examples/easy-rsa/ /etc/openvpn # easy-rsa isn't available by default for Debian Jessie and newer if [[ ! -d /etc/openvpn/easy-rsa/2.0/ ]]; then wget --no-check-certificate -O ~/easy-rsa.tar.gz https://github.com/OpenVPN/easy-rsa/archive/2.2.2.tar.gz tar xzf ~/easy-rsa.tar.gz -C ~/ mkdir -p /etc/openvpn/easy-rsa/2.0/ cp ~/easy-rsa-2.2.2/easy-rsa/2.0/* /etc/openvpn/easy-rsa/2.0/ rm -rf ~/easy-rsa-2.2.2 rm -rf ~/easy-rsa.tar.gz fi cd /etc/openvpn/easy-rsa/2.0/ # Let's fix one thing first... cp -u -p openssl-1.0.0.cnf openssl.cnf # Fuck you NSA - 1024 bits was the default for Debian Wheezy and older sed -i 's|export KEY_SIZE=1024|export KEY_SIZE=2048|' /etc/openvpn/easy-rsa/2.0/vars # Create the PKI . /etc/openvpn/easy-rsa/2.0/vars . /etc/openvpn/easy-rsa/2.0/clean-all # The following lines are from build-ca. I don't use that script directly # because it's interactive and we don't want that. Yes, this could break # the installation script if build-ca changes in the future. export EASY_RSA="${EASY_RSA:-.}" "$EASY_RSA/pkitool" --initca $* # Same as the last time, we are going to run build-key-server export EASY_RSA="${EASY_RSA:-.}" "$EASY_RSA/pkitool" --server server # Now the client keys. We need to set KEY_CN or the stupid pkitool will cry export KEY_CN="$CLIENT" export EASY_RSA="${EASY_RSA:-.}" "$EASY_RSA/pkitool" $CLIENT # DH params . /etc/openvpn/easy-rsa/2.0/build-dh # Let's configure the server cd /usr/share/doc/openvpn/examples/sample-config-files gunzip -d server.conf.gz cp server.conf /etc/openvpn/ cd /etc/openvpn/easy-rsa/2.0/keys cp ca.crt ca.key dh2048.pem server.crt server.key /etc/openvpn cd /etc/openvpn/ # Set the server configuration sed -i 's|dh dh1024.pem|dh dh2048.pem|' server.conf sed -i 's|;push "redirect-gateway def1 bypass-dhcp"|push "redirect-gateway def1 bypass-dhcp"|' server.conf sed -i "s|port 1194|port $PORT|" server.conf # Obtain the resolvers from resolv.conf and use them for OpenVPN grep -v '#' /etc/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 sed -i "/;push \"dhcp-option DNS 208.67.220.220\"/a\push \"dhcp-option DNS $line\"" server.conf done # Listen at port 53 too if user wants that if [[ "$ALTPORT" = 'y' ]]; then iptables -t nat -A PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-port $PORT sed -i "/# By default this script does nothing./a\iptables -t nat -A PREROUTING -p udp -d $IP --dport 53 -j REDIRECT --to-port $PORT" /etc/rc.local fi # Enable net.ipv4.ip_forward for the system sed -i 's|#net.ipv4.ip_forward=1|net.ipv4.ip_forward=1|' /etc/sysctl.conf # Avoid an unneeded reboot echo 1 > /proc/sys/net/ipv4/ip_forward # Set iptables iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to $IP sed -i "/# By default this script does nothing./a\iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to $IP" /etc/rc.local # And finally, restart OpenVPN /etc/init.d/openvpn restart # Try to detect a NATed connection and ask about it to potential LowEndSpirit # users EXTERNALIP=$(wget -qO- ipv4.icanhazip.com) if [[ "$IP" != "$EXTERNALIP" ]]; then echo "" echo "Looks like your server is behind a NAT!" echo "" echo "If your server is NATed (LowEndSpirit), I need to know the external IP" echo "If that's not the case, just ignore this and leave the next field blank" read -p "External IP: " -e USEREXTERNALIP if [[ "$USEREXTERNALIP" != "" ]]; then IP=$USEREXTERNALIP fi fi # IP/port set on the default client.conf so we can add further users # without asking for them sed -i "s|remote my-server-1 1194|remote $IP $PORT|" /usr/share/doc/openvpn/examples/sample-config-files/client.conf # Generate the client config bundle newclient "$CLIENT" echo "" echo "Finished!" echo "" echo "Your client config is available at ~/ovpn-$CLIENT.tar.gz" echo "If you want to add more clients, you simply need to run this script another time!" fi