Subversion Repositories ALCASAR

#!/bin/bash

# $Id: alcasar-iptables-bypass.sh 2957 2021-05-26 13:06:56Z rexy $

# alcasar-iptables-bypass.sh

# by Rexy - 3abtux

# This script is distributed under the Gnu General Public License (GPL)

# applique les regles du parefeu en mode ByPass

# put the firewall rules in 'ByPass' mode

CONF_FILE="/usr/local/etc/alcasar.conf"

private_ip_mask=`grep ^PRIVATE_IP= $CONF_FILE|cut -d"=" -f2`

private_ip_mask=${private_ip_mask:=192.168.182.1/24}

private_network=`/bin/ipcalc -n $private_ip_mask|cut -d"=" -f2`		# LAN IP address (ie.: 192.168.182.0)

private_prefix=`/bin/ipcalc -p $private_ip_mask|cut -d"=" -f2`		# LAN prefix (ie. 24)

IPTABLES="/sbin/iptables"

EXTIF=`grep ^EXTIF= $CONF_FILE|cut -d"=" -f2`				# EXTernal InterFace

INTIF=`grep ^INTIF= $CONF_FILE|cut -d"=" -f2`				# INTernal InterFace

PRIVATE_NETWORK_MASK=$private_network/$private_prefix			# Lan IP address + prefix (192.168.182.0/24)

PRIVATE_IP=`echo $private_ip_mask | cut -d"/" -f1`			# ALCASAR LAN IP address

public_ip_mask=`grep ^PUBLIC_IP= $CONF_FILE|cut -d"=" -f2`		# ALCASAR WAN IP address

if [[ "$public_ip_mask" == "dhcp" ]]

then

	PTN="\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\/([012]?[0-9]|3[0-2])\b"

	public_ip_mask=`ip addr show $EXTIF | egrep -o $PTN`

fi

PUBLIC_IP=`echo $public_ip_mask | cut -d"/" -f1`

SSH=`grep ^SSH= $CONF_FILE|cut -d"=" -f2`				# sshd active (on/off)

SSH=${SSH:=off}

SSH_ADMIN_FROM=`grep ^SSH_ADMIN_FROM= $CONF_FILE|cut -d"=" -f2`

SSH_ADMIN_FROM=${SSH_ADMIN_FROM:="0.0.0.0/0.0.0.0"}				# WAN IP address to reduce ssh access (all ip allowed on LAN side)

# On vide (flush) toutes les règles existantes

# Flush all existing rules

$IPTABLES -F

$IPTABLES -t nat -F

$IPTABLES -F INPUT

$IPTABLES -F FORWARD

$IPTABLES -F OUTPUT

# On indique les politiques par défaut

# Default policies

$IPTABLES -P INPUT DROP

$IPTABLES -P FORWARD DROP

$IPTABLES -P OUTPUT ACCEPT

$IPTABLES -t nat -P PREROUTING ACCEPT

$IPTABLES -t nat -P POSTROUTING ACCEPT

$IPTABLES -t nat -P OUTPUT ACCEPT

# On efface toutes les chaînes qui ne sont pas par défaut dans les tables filter et nat

# Flush non default rules on filter and nat tables

$IPTABLES -X

$IPTABLES -t nat -X

# On autorise tout sur loopback

# accept all on loopback

$IPTABLES -A OUTPUT -o lo -j ACCEPT

$IPTABLES -A INPUT -i lo -j ACCEPT

# Insertion de règles de blocage (Devel)

# Here, we add block rules (Devel)

if [ -s /usr/local/etc/alcasar-ip-blocked ]; then

	while read ip_line

	do

		ip_on=`echo $ip_line|cut -b1`

		if [ $ip_on != "#" ]

		then	

			ip_blocked=`echo $ip_line|cut -d" " -f1`

			$IPTABLES -A FORWARD -d $ip_blocked -j NFLOG --nflog-group 1 --nflog-prefix "RULE IP-blocked -- REJECT "

			$IPTABLES -A FORWARD -d $ip_blocked -j REJECT

		fi

	done < /usr/local/etc/alcasar-ip-blocked

fi

# SSHD rules if activate

if [ $SSH = on ]

	then

	$IPTABLES -A INPUT -i $INTIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -m state --state NEW -j NFLOG --nflog-group 2 --nflog-prefix "RULE ssh-from-LAN -- ACCEPT"

	$IPTABLES -A INPUT -i $INTIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -m state --state NEW -j ACCEPT

	$IPTABLES -A INPUT -i $EXTIF -s $SSH_ADMIN_FROM -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW --syn -j NFLOG --nflog-group 2 --nflog-prefix "RULE ssh-from-WAN -- ACCEPT"

	$IPTABLES -A INPUT -i $EXTIF -s $SSH_ADMIN_FROM -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW -j ACCEPT

fi

# Insertion de règles locales

# Here, we add local rules (i.e. VPN from Internet)

if [ -f /usr/local/etc/alcasar-iptables-local.sh ]; then

	. /usr/local/etc/alcasar-iptables-local.sh

fi

# on autorise les requêtes dhcp

# accept dhcp

$IPTABLES -A INPUT -i $INTIF -p udp -m udp --sport bootpc --dport bootps -j ACCEPT

# On drop le broadcast et le multicast sur les interfaces (sans Log)

# Drop broadcast & multicast

$IPTABLES -A INPUT -m addrtype --dst-type BROADCAST,MULTICAST -j DROP

# On laisse passer les ICMP echo-request et echo-reply en provenance du LAN

# Allow ping (icmp N°0 & 8) from LAN

$IPTABLES -A INPUT -i $INTIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 0 -j ACCEPT

$IPTABLES -A INPUT -i $INTIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 8 -j ACCEPT

# On autorise les retours de connexions légitimes par FORWARD

# Conntrack on forward

$IPTABLES -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

# On autorise les demandes de connexions sortantes

$IPTABLES -A FORWARD -i $INTIF -m state --state NEW -j NFLOG --nflog-group 1 --nflog-prefix "RULE Transfert -- ACCEPT "

$IPTABLES -A FORWARD -i $INTIF -m state --state NEW -j ACCEPT

# On autorise les flux entrant ntp et dns via INTIF

$IPTABLES -A INPUT -i $INTIF -d $PRIVATE_IP -p udp --dport domain -j ACCEPT

$IPTABLES -A INPUT -i $INTIF -d $PRIVATE_IP -p udp --dport ntp -j ACCEPT

# On autorise le retour des connexions entrante déjà acceptées

$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

# On interdit et on log le reste sur les 2 interfaces d'accès

$IPTABLES -A INPUT -i $INTIF -j NFLOG --nflog-group 1 --nflog-prefix "RULE rej-int -- REJECT "

$IPTABLES -A INPUT -i $EXTIF -j NFLOG --nflog-group 1 --nflog-prefix "RULE rej-ext -- REJECT "

$IPTABLES -A INPUT -p tcp -j REJECT --reject-with tcp-reset

$IPTABLES -A INPUT -p udp -j REJECT --reject-with icmp-port-unreachable

# On active le masquage d'adresse par translation (NAT)

$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE

# on ne sauvegarde pas les règles. En cas de reboot, on repasse ainsi automatiquement en mode normal (bypass -off)

# Fin du script des regles du parefeu