diff --git a/README.md b/README.md
index 9015da3..7d2db73 100644
--- a/README.md
+++ b/README.md
@@ -10,9 +10,12 @@ This fork includes :
- Better encryption (see below)
- TLS 1.2 only
- AES-256-CBC and SHA-512 for HMAC (instead of BF-128-CBC and SHA1)
+- Run server in unprivileged mode, reducing risks to the system
+- TLS-auth to help [thwart DoS attacks](https://openvpn.net/index.php/open-source/documentation/howto.html#security) and provide a 2nd line of defense to the TLS channel.
- [FDN's DNS Servers](http://www.fdn.fr/actions/dns/)
- Nearest [OpenNIC DNS Servers](https://www.opennicproject.org/)
- Up-to-date OpenVPN (2.3.11) thanks to [EPEL](http://fedoraproject.org/wiki/EPEL) and [swupdate.openvpn.net](https://community.openvpn.net/openvpn/wiki/OpenvpnSoftwareRepos)
+- Support for either SNAT or MASQUERADE for forwarding
- Every feature of the [original script](https://github.com/Nyr/openvpn-install) (I check periodically to sync the latest commits from source)
## Variants
diff --git a/openvpn-install.sh b/openvpn-install.sh
index 0984f41..7b33f04 100644
--- a/openvpn-install.sh
+++ b/openvpn-install.sh
@@ -56,6 +56,10 @@ newclient () {
echo "" >> ~/$1.ovpn
cat /etc/openvpn/easy-rsa/pki/private/$1.key >> ~/$1.ovpn
echo "" >> ~/$1.ovpn
+ echo "key-direction 1" >> ~/$1.ovpn
+ echo "" >> ~/$1.ovpn
+ cat /etc/openvpn/tls-auth.key >> ~/$1.ovpn
+ echo "" >> ~/$1.ovpn
}
@@ -141,7 +145,7 @@ if [[ -e /etc/openvpn/server.conf ]]; then
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
+ sed -i '/iptables -t nat -A POSTROUTING -s 10.8.0.0\/24 /d' $RCLOCAL
if hash sestatus 2>/dev/null; then
if sestatus | grep "Current mode" | grep -qs "enforcing"; then
if [[ "$PORT" != '1194' ]]; then
@@ -200,6 +204,14 @@ else
echo " 5) Google"
read -p "DNS [1-6]: " -e -i 2 DNS
echo ""
+ echo "Some setups (e.g. Amazon Web Services), require use of MASQUERADE rather than SNAT"
+ echo "Which forwarding method do you want to use [if unsure, leave as default]?"
+ echo " 1) SNAT (default)"
+ echo " 2) MASQUERADE"
+ while [[ $FORWARD_TYPE != "1" && $FORWARD_TYPE != "2" ]]; do
+ read -p "Forwarding type: " -e -i 1 FORWARD_TYPE
+ done
+ 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
@@ -241,6 +253,12 @@ else
yum install epel-release -y
yum install openvpn iptables openssl wget ca-certificates curl -y
fi
+ # find out if the machine uses nogroup or nobody for the permissionless group
+ if grep -qs "^nogroup:" /etc/group; then
+ NOGROUP=nogroup
+ else
+ NOGROUP=nobody
+ fi
# An old version of easy-rsa was available by default in some openvpn packages
if [[ -d /etc/openvpn/easy-rsa/ ]]; then
@@ -273,8 +291,12 @@ set_var EASYRSA_DIGEST "sha384"" > vars
./easyrsa build-server-full server nopass
./easyrsa build-client-full $CLIENT nopass
./easyrsa gen-crl
+ # generate tls-auth key
+ openvpn --genkey --secret /etc/openvpn/tls-auth.key
# 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
+ # Make cert revocation list readable for non-root
+ chmod 644 /etc/openvpn/crl.pem
# Generate server.conf
echo "port $PORT
proto udp
@@ -283,6 +305,8 @@ ca ca.crt
cert server.crt
key server.key
dh dh.pem
+user nobody
+group $NOGROUP
topology subnet
server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
@@ -291,7 +315,6 @@ auth SHA512
tls-version-min 1.2" > /etc/openvpn/server.conf
if [[ "$VARIANT" = '1' ]]; then
# If the user selected the fast, less hardened version
- # Or if the user selected a non-existant variant, we fallback to fast
echo "tls-cipher TLS-DHE-RSA-WITH-AES-128-GCM-SHA256" >> /etc/openvpn/server.conf
elif [[ "$VARIANT" = '2' ]]; then
# If the user selected the relatively slow, ultra hardened version
@@ -313,10 +336,8 @@ tls-version-min 1.2" > /etc/openvpn/server.conf
3) #OpenNIC
#Getting the nearest OpenNIC servers using the geoip API
read ns1 ns2 <<< $(curl -s https://api.opennicproject.org/geoip/ | head -2 | awk '{print $1}')
- echo -e "nameserver $ns1
- nameserver $ns2" >> /etc/resolv.conf #Set the DNS servers
- echo "push "dhcp-option DNS $ns1"" >> /etc/openvpn/server.conf
- echo "push "dhcp-option DNS $ns2"" >> /etc/openvpn/server.conf
+ echo "push \"dhcp-option DNS $ns1\"" >> /etc/openvpn/server.conf
+ echo "push \"dhcp-option DNS $ns2\"" >> /etc/openvpn/server.conf
;;
4) #OpenDNS
echo 'push "dhcp-option DNS 208.67.222.222"' >> /etc/openvpn/server.conf
@@ -330,7 +351,9 @@ tls-version-min 1.2" > /etc/openvpn/server.conf
echo "keepalive 10 120
persist-key
persist-tun
-crl-verify crl.pem" >> /etc/openvpn/server.conf
+crl-verify crl.pem
+tls-server
+tls-auth tls-auth.key 0" >> /etc/openvpn/server.conf
# Enable net.ipv4.ip_forward for the system
if [[ "$OS" = 'debian' ]]; then
sed -i 's|#net.ipv4.ip_forward=1|net.ipv4.ip_forward=1|' /etc/sysctl.conf
@@ -345,8 +368,13 @@ crl-verify crl.pem" >> /etc/openvpn/server.conf
# 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" $RCLOCAL
+ if [[ "$FORWARD_TYPE" = '1' ]]; then
+ 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
+ else
+ iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
+ sed -i "1 a\iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE" $RCLOCAL
+ fi
if pgrep firewalld; then
# We don't use --add-service=openvpn because that would only work with
# the default port. Using both permanent and not permanent rules to
@@ -402,9 +430,10 @@ crl-verify crl.pem" >> /etc/openvpn/server.conf
echo ""
echo "Looks like your server is behind a NAT!"
echo ""
- echo "If your server is NATed (e.g. LowEndSpirit, Scaleway), I need to know the external IP"
- echo "If that's not the case, just ignore this and leave the next field blank"
- read -p "External IP: " -e USEREXTERNALIP
+ echo "If your server is NATed (e.g. LowEndSpirit, Scaleway, or behind a router),"
+ echo "then I need to know the address that can be used to access it from outside."
+ echo "If that's not the case, just ignore this and leave the next field blank"
+ read -p "External IP or domain name: " -e USEREXTERNALIP
if [[ "$USEREXTERNALIP" != "" ]]; then
IP=$USEREXTERNALIP
fi
@@ -421,10 +450,10 @@ persist-tun
remote-cert-tls server
cipher AES-256-CBC
auth SHA512
-tls-version-min 1.2" > /etc/openvpn/client-common.txt
+tls-version-min 1.2
+tls-client" > /etc/openvpn/client-common.txt
if [[ "$VARIANT" = '1' ]]; then
# If the user selected the fast, less hardened version
- # Or if the user selected a non-existant variant, we fallback to fast
echo "tls-cipher TLS-DHE-RSA-WITH-AES-128-GCM-SHA256" >> /etc/openvpn/client-common.txt
elif [[ "$VARIANT" = '2' ]]; then
# If the user selected the relatively slow, ultra hardened version