Openvpn automatic install

#!/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


# 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" $CLIENT
# Let's generate the client config
mkdir ~/ovpn-$CLIENT
cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf ~/ovpn-$CLIENT/$CLIENT.conf
cp /etc/openvpn/easy-rsa/2.0/keys/ca.crt ~/ovpn-$CLIENT
cp /etc/openvpn/easy-rsa/2.0/keys/$CLIENT.crt ~/ovpn-$CLIENT
cp /etc/openvpn/easy-rsa/2.0/keys/$CLIENT.key ~/ovpn-$CLIENT
cd ~/ovpn-$CLIENT
sed -i "s|cert client.crt|cert $CLIENT.crt|" $CLIENT.conf
sed -i "s|key client.key|key $CLIENT.key|" $CLIENT.conf
tar -czf ../ovpn-$CLIENT.tar.gz $CLIENT.conf ca.crt $CLIENT.crt $CLIENT.key
cd ~/
rm -rf ovpn-$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
cat /etc/resolv.conf | grep -v '#' | 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 $IP" /etc/rc.local
# And finally, restart OpenVPN
/etc/init.d/openvpn restart
# Let's generate the client config
mkdir ~/ovpn-$CLIENT
# 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 $PORT|" /usr/share/doc/openvpn/examples/sample-config-files/client.conf
cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf ~/ovpn-$CLIENT/$CLIENT.conf
cp /etc/openvpn/easy-rsa/2.0/keys/ca.crt ~/ovpn-$CLIENT
cp /etc/openvpn/easy-rsa/2.0/keys/$CLIENT.crt ~/ovpn-$CLIENT
cp /etc/openvpn/easy-rsa/2.0/keys/$CLIENT.key ~/ovpn-$CLIENT
cd ~/ovpn-$CLIENT
sed -i "s|cert client.crt|cert $CLIENT.crt|" $CLIENT.conf
sed -i "s|key client.key|key $CLIENT.key|" $CLIENT.conf
tar -czf ../ovpn-$CLIENT.tar.gz $CLIENT.conf ca.crt $CLIENT.crt $CLIENT.key
cd ~/
rm -rf ovpn-$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