#!/bin/bash # OpenVPN road warrior installer for Debian, Ubuntu and CentOS # This script will work on Debian, Ubuntu, CentOS and probably other distros # of the same families, although no support is offered for them. It isn't # bulletproof but it will probably work if you simply want to setup a VPN on # your Debian/Ubuntu/CentOS box. It has been designed to be as unobtrusive and # universal as possible. if [[ "$EUID" -ne 0 ]]; then echo "Sorry, you need to run this as root" exit 1 fi if [[ ! -e /dev/net/tun ]]; then echo "TUN/TAP is not available" exit 2 fi if grep -qs "CentOS release 5" "/etc/redhat-release"; then echo "CentOS 5 is too old and not supported" exit 3 fi if [[ -e /etc/debian_version ]]; then OS=debian RCLOCAL='/etc/rc.local' elif [[ -e /etc/centos-release || -e /etc/redhat-release ]]; then OS=centos RCLOCAL='/etc/rc.d/rc.local' # Needed for CentOS 7 chmod +x /etc/rc.d/rc.local else echo "Looks like you aren't running this installer on a Debian, Ubuntu or CentOS system" exit 4 fi newclient () { # Generates the custom client.ovpn cp /etc/openvpn/client-common.txt ~/$1.ovpn echo "" >> ~/$1.ovpn cat /etc/openvpn/easy-rsa/pki/ca.crt >> ~/$1.ovpn echo "" >> ~/$1.ovpn echo "" >> ~/$1.ovpn cat /etc/openvpn/easy-rsa/pki/issued/$1.crt >> ~/$1.ovpn echo "" >> ~/$1.ovpn echo "" >> ~/$1.ovpn cat /etc/openvpn/easy-rsa/pki/private/$1.key >> ~/$1.ovpn echo "" >> ~/$1.ovpn } # Try to get our IP from the system and fallback to the Internet. # I do this to make the script compatible with NATed servers (lowendspirit.com) # and to avoid getting an IPv6. IP=$(ip addr | grep 'inet' | grep -v inet6 | grep -vE '127\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | grep -o -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' | 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 "" echo "What do you want to do?" echo " 1) Add a cert for a new user" echo " 2) Revoke existing user cert" echo " 3) Remove OpenVPN" echo " 4) Exit" 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/ ./easyrsa build-client-full $CLIENT nopass # Generates the custom client.ovpn newclient "$CLIENT" echo "" echo "Client $CLIENT added, certs available at ~/$CLIENT.ovpn" exit ;; 2) # This option could be documented a bit better and maybe even be simplimplified # ...but what can I say, I want some sleep too NUMBEROFCLIENTS=$(tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep -c "^V") if [[ "$NUMBEROFCLIENTS" = '0' ]]; then echo "" echo "You have no existing clients!" exit 5 fi echo "" echo "Select the existing client certificate you want to revoke" tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | nl -s ') ' if [[ "$NUMBEROFCLIENTS" = '1' ]]; then read -p "Select one client [1]: " CLIENTNUMBER else read -p "Select one client [1-$NUMBEROFCLIENTS]: " CLIENTNUMBER fi CLIENT=$(tail -n +2 /etc/openvpn/easy-rsa/pki/index.txt | grep "^V" | cut -d '=' -f 2 | sed -n "$CLIENTNUMBER"p) cd /etc/openvpn/easy-rsa/ ./easyrsa --batch revoke $CLIENT ./easyrsa gen-crl rm -rf pki/reqs/$CLIENT.req rm -rf pki/private/$CLIENT.key rm -rf pki/issued/$CLIENT.crt rm -rf /etc/openvpn/crl.pem cp /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn/crl.pem echo "" echo "Certificate for client $CLIENT revoked" exit ;; 3) echo "" read -p "Do you really want to remove OpenVPN? [y/n]: " -e -i n REMOVE if [[ "$REMOVE" = 'y' ]]; then PORT=$(grep '^port ' /etc/openvpn/server.conf | cut -d " " -f 2) if pgrep firewalld; then # Using both permanent and not permanent rules to avoid a firewalld reload. firewall-cmd --zone=public --remove-port=$PORT/udp firewall-cmd --zone=trusted --remove-source=10.8.0.0/24 firewall-cmd --permanent --zone=public --remove-port=$PORT/udp firewall-cmd --permanent --zone=trusted --remove-source=10.8.0.0/24 fi if iptables -L | grep -qE 'REJECT|DROP'; then sed -i "/iptables -I INPUT -p udp --dport $PORT -j ACCEPT/d" $RCLOCAL sed -i "/iptables -I FORWARD -s 10.8.0.0\/24 -j ACCEPT/d" $RCLOCAL sed -i "/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT/d" $RCLOCAL fi sed -i '/iptables -t nat -A POSTROUTING -s 10.8.0.0\/24 -j SNAT --to /d' $RCLOCAL if which sestatus; then if sestatus | grep "Current mode" | grep -qs "enforcing"; then if [[ "$PORT" != '1194' ]]; then semanage port -d -t openvpn_port_t -p udp $PORT fi fi fi if [[ "$OS" = 'debian' ]]; then apt-get remove --purge -y openvpn openvpn-blacklist else yum remove openvpn -y fi rm -rf /etc/openvpn rm -rf /usr/share/doc/openvpn* echo "" echo "OpenVPN removed!" else echo "" echo "Removal aborted!" fi exit ;; 4) exit;; esac done else clear 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 $IP IP echo "" echo "What port do you want for OpenVPN?" read -p "Port: " -e -i 1194 PORT echo "" echo "What DNS do you want to use with the VPN?" echo " 1) Current system resolvers" echo " 2) Google" echo " 3) OpenDNS" echo " 4) NTT" echo " 5) FDN" echo " 6) Hurricane Electric" read -p "DNS [1-6]: " -e -i 1 DNS echo "" echo "Finally, tell me your name for the client cert" echo "Please, use one word only, no special characters" read -p "Client name: " -e -i client CLIENT echo "" echo "Okay, that was all I needed. We are ready to setup your OpenVPN server now" read -n1 -r -p "Press any key to continue..." if [[ "$OS" = 'debian' ]]; then apt-get update apt-get install openvpn iptables openssl ca-certificates -y else # Else, the distro is CentOS yum install epel-release -y yum install openvpn iptables openssl wget ca-certificates -y fi # An old version of easy-rsa was available by default in some openvpn packages if [[ -d /etc/openvpn/easy-rsa/ ]]; then rm -rf /etc/openvpn/easy-rsa/ fi # Get easy-rsa wget -O ~/EasyRSA-3.0.1.tgz https://github.com/OpenVPN/easy-rsa/releases/download/3.0.1/EasyRSA-3.0.1.tgz tar xzf ~/EasyRSA-3.0.1.tgz -C ~/ mv ~/EasyRSA-3.0.1/ /etc/openvpn/ mv /etc/openvpn/EasyRSA-3.0.1/ /etc/openvpn/easy-rsa/ chown -R root:root /etc/openvpn/easy-rsa/ rm -rf ~/EasyRSA-3.0.1.tgz cd /etc/openvpn/easy-rsa/ # Create the PKI, set up the CA, the DH params and the server + client certificates ./easyrsa init-pki ./easyrsa --batch build-ca nopass ./easyrsa gen-dh ./easyrsa build-server-full server nopass ./easyrsa build-client-full $CLIENT nopass ./easyrsa gen-crl # Move the stuff we need cp pki/ca.crt pki/private/ca.key pki/dh.pem pki/issued/server.crt pki/private/server.key /etc/openvpn/easy-rsa/pki/crl.pem /etc/openvpn # Generate server.conf echo "port $PORT proto udp dev tun sndbuf 0 rcvbuf 0 ca ca.crt cert server.crt key server.key dh dh.pem cipher AES-256-CBC tls-version-min 1.2 topology subnet server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt" > /etc/openvpn/server.conf echo 'push "redirect-gateway def1 bypass-dhcp"' >> /etc/openvpn/server.conf # DNS case $DNS in 1) # 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 echo "push \"dhcp-option DNS $line\"" >> /etc/openvpn/server.conf done ;; 2) echo 'push "dhcp-option DNS 8.8.8.8"' >> /etc/openvpn/server.conf echo 'push "dhcp-option DNS 8.8.4.4"' >> /etc/openvpn/server.conf ;; 3) echo 'push "dhcp-option DNS 208.67.222.222"' >> /etc/openvpn/server.conf echo 'push "dhcp-option DNS 208.67.220.220"' >> /etc/openvpn/server.conf ;; 4) echo 'push "dhcp-option DNS 129.250.35.250"' >> /etc/openvpn/server.conf echo 'push "dhcp-option DNS 129.250.35.251"' >> /etc/openvpn/server.conf ;; 5) echo 'push "dhcp-option DNS 80.67.169.12"' >> /etc/openvpn/server.conf echo 'push "dhcp-option DNS 80.67.169.40"' >> /etc/openvpn/server.conf ;; 6) echo 'push "dhcp-option DNS 74.82.42.42"' >> /etc/openvpn/server.conf ;; esac echo "keepalive 10 120 comp-lzo persist-key persist-tun crl-verify crl.pem" >> /etc/openvpn/server.conf # Enable net.ipv4.ip_forward for the system if [[ "$OS" = 'debian' ]]; then sed -i 's|#net.ipv4.ip_forward=1|net.ipv4.ip_forward=1|' /etc/sysctl.conf else # CentOS 5 and 6 sed -i 's|net.ipv4.ip_forward = 0|net.ipv4.ip_forward = 1|' /etc/sysctl.conf # CentOS 7 if ! grep -q "net.ipv4.ip_forward=1" "/etc/sysctl.conf"; then echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf fi fi # Avoid an unneeded reboot echo 1 > /proc/sys/net/ipv4/ip_forward # Set NAT for the VPN subnet iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to $IP sed -i "1 a\iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j SNAT --to $IP" $RCLOCAL if pgrep firewalld; then # We don't use --add-service=openvpn because that would only work with # the default port. Using both permanent and not permanent rules to # avoid a firewalld reload. firewall-cmd --zone=public --add-port=$PORT/udp firewall-cmd --zone=trusted --add-source=10.8.0.0/24 firewall-cmd --permanent --zone=public --add-port=$PORT/udp firewall-cmd --permanent --zone=trusted --add-source=10.8.0.0/24 fi if iptables -L | grep -qE 'REJECT|DROP'; then # If iptables has at least one REJECT rule, we asume this is needed. # Not the best approach but I can't think of other and this shouldn't # cause problems. iptables -I INPUT -p udp --dport $PORT -j ACCEPT iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT sed -i "1 a\iptables -I INPUT -p udp --dport $PORT -j ACCEPT" $RCLOCAL sed -i "1 a\iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT" $RCLOCAL sed -i "1 a\iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT" $RCLOCAL fi # If SELinux is enabled and a custom port was selected, we need this if which sestatus; then if sestatus | grep "Current mode" | grep -qs "enforcing"; then if [[ "$PORT" != '1194' ]]; then # semanage isn't available in CentOS 6 by default if ! which semanage > /dev/null 2>&1; then yum install policycoreutils-python -y fi semanage port -a -t openvpn_port_t -p udp $PORT fi fi fi # And finally, restart OpenVPN if [[ "$OS" = 'debian' ]]; then # Little hack to check for systemd if pgrep systemd-journal; then systemctl restart openvpn@server.service else /etc/init.d/openvpn restart fi else if pgrep systemd-journal; then systemctl restart openvpn@server.service systemctl enable openvpn@server.service else service openvpn restart chkconfig openvpn on fi fi # 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 # client-common.txt is created so we have a template to add further users later echo "client dev tun proto udp sndbuf 0 rcvbuf 0 remote $IP $PORT resolv-retry infinite nobind persist-key persist-tun remote-cert-tls server cipher AES-256-CBC tls-version-min 1.2 comp-lzo" > /etc/openvpn/client-common.txt # Generates the custom client.ovpn newclient "$CLIENT" echo "" echo "Finished!" echo "" echo "Your client config is available at ~/$CLIENT.ovpn" echo "If you want to add more clients, you simply need to run this script another time!" fi