From a6048d509fff11c28cbabc36633f76c1ac5ce988 Mon Sep 17 00:00:00 2001
From: Nyr <me@nyr.be>
Date: Fri, 7 Jun 2019 16:17:14 +0200
Subject: [PATCH] Switch to systemd for iptables configuration

See #464.
---
 openvpn-install.sh | 52 +++++++++++++++++-----------------------------
 1 file changed, 19 insertions(+), 33 deletions(-)

diff --git a/openvpn-install.sh b/openvpn-install.sh
index 9a500d8..c39d959 100644
--- a/openvpn-install.sh
+++ b/openvpn-install.sh
@@ -25,11 +25,9 @@ fi
 if [[ -e /etc/debian_version ]]; then
 	OS=debian
 	GROUPNAME=nogroup
-	RCLOCAL='/etc/rc.local'
 elif [[ -e /etc/centos-release || -e /etc/redhat-release ]]; then
 	OS=centos
 	GROUPNAME=nobody
-	RCLOCAL='/etc/rc.d/rc.local'
 else
 	echo "Looks like you aren't running this installer on Debian, Ubuntu or CentOS"
 	exit
@@ -133,17 +131,8 @@ if [[ -e /etc/openvpn/server.conf ]]; then
 					firewall-cmd --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
 					firewall-cmd --permanent --direct --remove-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
 				else
-					IP=$(grep 'iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to ' $RCLOCAL | cut -d " " -f 14)
-					iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
-					sed -i '/iptables -t nat -A POSTROUTING -s 10.8.0.0\/24 ! -d 10.8.0.0\/24 -j SNAT --to /d' $RCLOCAL
-					if iptables -L -n | grep -qE '^ACCEPT'; then
-						iptables -D INPUT -p $PROTOCOL --dport $PORT -j ACCEPT
-						iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT
-						iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
-						sed -i "/iptables -I INPUT -p $PROTOCOL --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" $RCLOCAL
-					fi
+					systemctl disable --now openvpn-iptables.service
+					rm -f /etc/systemd/system/openvpn-iptables.service
 				fi
 				if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$PORT" != '1194' ]]; then
 					semanage port -d -t openvpn_port_t -p $PROTOCOL $PORT
@@ -328,26 +317,23 @@ crl-verify crl.pem" >> /etc/openvpn/server.conf
 		firewall-cmd --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
 		firewall-cmd --permanent --direct --add-rule ipv4 nat POSTROUTING 0 -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
 	else
-		# Needed to use rc.local with some systemd distros
-		if [[ "$OS" = 'debian' && ! -e $RCLOCAL ]]; then
-			echo '#!/bin/sh -e
-exit 0' > $RCLOCAL
-		fi
-		chmod +x $RCLOCAL
-		# Set NAT for the VPN subnet
-		iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
-		sed -i "1 a\iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP" $RCLOCAL
-		if iptables -L -n | 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 $PROTOCOL --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 $PROTOCOL --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
+		# Create a service to set up persistent iptables rules
+		echo "[Unit]
+Before=network.target
+[Service]
+Type=oneshot
+ExecStart=/sbin/iptables -t nat -A POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
+ExecStart=/sbin/iptables -I INPUT -p $PROTOCOL --dport $PORT -j ACCEPT
+ExecStart=/sbin/iptables -I FORWARD -s 10.8.0.0/24 -j ACCEPT
+ExecStart=/sbin/iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
+ExecStop=/sbin/iptables -t nat -D POSTROUTING -s 10.8.0.0/24 ! -d 10.8.0.0/24 -j SNAT --to $IP
+ExecStop=/sbin/iptables -D INPUT -p $PROTOCOL --dport $PORT -j ACCEPT
+ExecStop=/sbin/iptables -D FORWARD -s 10.8.0.0/24 -j ACCEPT
+ExecStop=/sbin/iptables -D FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
+RemainAfterExit=yes
+[Install]
+WantedBy=multi-user.target" > /etc/systemd/system/openvpn-iptables.service
+		systemctl enable --now openvpn-iptables.service
 	fi
 	# If SELinux is enabled and a custom port was selected, we need this
 	if sestatus 2>/dev/null | grep "Current mode" | grep -q "enforcing" && [[ "$PORT" != '1194' ]]; then