WebSVN – ALCASAR – Diff – /scripts/alcasar-iptables.sh


#!/bin/sh
# $Id: alcasar-iptables.sh 688 2011-07-28 22:20:18Z richard $
# Script de mise en place des regles du parefeu d'Alcasar (mode normal)
# This script write the netfilter rules for ALCASAR
# Rexy - 3abtux - CPN
#
# Reminders
# There are three channels for log :
#	1 (default) for tracability;
#	2 for secure admin (ssh);
#	3 for exterior access attempts.
# The French Security Agency (ANSSI) rules was applied by 'alcasar.sh' script
# The bootps/dhcp (67) port is always open on tun0/eth1 by coova 
 
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)
dns1=`grep DNS1 $conf_file|cut -d"=" -f2`				# first public DNS server
dns1=${dns1:=208.67.220.220}
dns2=`grep DNS2 $conf_file|cut -d"=" -f2`				# second public DNS server
dns2=${dns2:=208.67.222.222}
PROTOCOLS_FILTERING=`grep PROTOCOLS_FILTERING $conf_file|cut -d"=" -f2`	# Network protocols filter (on/off)
PROTOCOLS_FILTERING=${PROTOCOLS_FILTERING:=off}
DNS_FILTERING=`grep DNS_FILTERING $conf_file|cut -d"=" -f2`		# DNS and URLs filter (on/off)
DNS_FILTERING=${DNS_FILTERING:=off}
QOS=`grep QOS $conf_file|cut -d"=" -f2`					# QOS (on/off)
QOS=${QOS:=off}
SSH=`grep SSH $conf_file|cut -d"=" -f2`					# sshd active (on/off)
SSH=${SSH:=off}
LDAP=`grep LDAP $conf_file|cut -d"=" -f2`				# ldap external server active (on/off)
LDAP=${LDAP:=off}
PRIVATE_NETWORK_MASK=$private_network/$private_prefix			# Lan IP address + prefix (192.168.182.0/24)
PRIVATE_IP=`echo $private_ip_mask | cut -d"/" -f1`			# ALCASAR LAN IP address
DNSSERVERS="$dns1,$dns2"						# first and second DNS IP servers addresses
EXTIF="eth0"
INTIF="eth1"
TUNIF="tun0"								# listen card for chilli daemon
IPTABLES="/sbin/iptables"
 
# Effacement des règles existantes
# Flush all existing rules
$IPTABLES -F
$IPTABLES -t nat -F
$IPTABLES -t mangle -F
$IPTABLES -F INPUT
$IPTABLES -F FORWARD
$IPTABLES -F OUTPUT
 
# Suppression des chaines utilisateurs sur les tables filter et nat
# Flush non default rules on filter and nat tables
$IPTABLES -X
$IPTABLES -t nat -X
 
# Stratégies par défaut
# Default policies
$IPTABLES -P INPUT DROP
$IPTABLES -P FORWARD DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -t nat -P PREROUTING ACCEPT
$IPTABLES -t nat -P POSTROUTING ACCEPT
$IPTABLES -t nat -P OUTPUT ACCEPT
 
# Tout passe sur loopback
# accept all on loopback
$IPTABLES -A INPUT -i lo -j ACCEPT
 
#############################
#       INTIF rules         #
#############################
# interdit l'accès à INTIF (n'est utile que lorsque chilli est arrêté).
# Reject INTIF access (only when chilli is down)
$IPTABLES -A INPUT -i $INTIF -j ULOG --ulog-prefix "RULE Protect1 -- REJECT "
$IPTABLES -A INPUT -i $INTIF -j REJECT
 
#############################
#  Local protection rules   #
#############################
# On stoppe les demande de connexions non conformes (NullScan, XMAS (tous flags à 1), NEW not SYN, etc.)
# Drop non standard connexions (NULLscans, XMAS, "NEW not SYN", etc.) 
$IPTABLES -A INPUT -p tcp --tcp-flags FIN,URG,PSH FIN,URG,PSH -j DROP
$IPTABLES -A INPUT -p tcp --tcp-flags ALL ALL -j DROP
$IPTABLES -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
$IPTABLES -A INPUT -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
$IPTABLES -A INPUT -p tcp -m tcp ! --syn -m state --state NEW -j DROP
 
# On ne traite pas les broadcasts et multicast
# Drop broadcast & multicast
$IPTABLES -A INPUT -m addrtype --dst-type BROADCAST,MULTICAST -j DROP
 
# Rejet des tentatives de création de tunnels DNS (même pour les utilisateurs authentifiés)  
# Deny forward DNS (even for authenticated users ...)
$IPTABLES -A FORWARD -i $TUNIF -p udp --dport domain -j REJECT --reject-with icmp-port-unreachable
$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport domain -j REJECT --reject-with tcp-reset
 
# On autorise les retours de connexions légitimes par FORWARD
# Conntrack on forward
$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
 
###############################
#  If DNS filter is activate  #
###############################
# Redirection des flux DNS vers le port 54 (dns+blackhole) sauf pour les IP en exceptions 
if [ $DNS_FILTERING = on ]; then
	# Compute exception IP
	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
	if [ $nb_exceptions != "0" ]
	then
		while read ip_exception 
		do
			$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -s $ip_exception -d $PRIVATE_IP --dport domain -j ACCEPT
		done < /usr/local/etc/alcasar-filter-exceptions
	fi
		$IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -d $PRIVATE_IP --dport domain -j REDIRECT --to-port 54
fi
#####################################
#  If protocols filter is activate  #
#####################################
 
if [ $PROTOCOLS_FILTERING = on ]; then
	# Compute exception IP (IP addresses that shouldn't be filtered)
	nb_exceptions=`wc -l /usr/local/etc/alcasar-filter-exceptions | cut -d" " -f1`
	if [ $nb_exceptions != "0" ]
	then
		while read ip_exception 
		do
			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ULOG --ulog-prefix "RULE IP-exception -- ACCEPT "
			$IPTABLES -A FORWARD -i $TUNIF -s $ip_exception -m state --state NEW -j ACCEPT
		done < /usr/local/etc/alcasar-filter-exceptions
	fi
	# Compute uamallowed IP (IP address of equipments connect between ALCASAR and Internet (DMZ, own servers, ...) 
	nb_exceptions=`wc -l /usr/local/etc/alcasar-uamallowed | cut -d" "  -f1`
	if [ $nb_exceptions != "0" ]
	then
		while read ip_allowed_line 
		do
			ip_allowed=`echo $ip_allowed_line|cut -d"\"" -f2`
			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ULOG --ulog-prefix "RULE IP-allowed -- ACCEPT "
			$IPTABLES -A FORWARD -i $TUNIF -d $ip_allowed -m state --state NEW -j ACCEPT
		done < /usr/local/etc/alcasar-uamallowed
	fi
	# Autorisation des protocoles non commentés
	# Allow non comment protocols
	while read svc_line
	do
		svc_on=`echo $svc_line|cut -b1`
		if [ $svc_on != "#" ]
		then	
			svc_name=`echo $svc_line|cut -d" " -f1`
			svc_port=`echo $svc_line|cut -d" " -f2`
			if [ $svc_name = "icmp" ]
			then
				$IPTABLES -A FORWARD -i $TUNIF -p icmp -j ACCEPT 
			else
				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_$svc_name -- ACCEPT "
				$IPTABLES -A FORWARD -i $TUNIF -p tcp --dport $svc_port -m state --state NEW -j ACCEPT
			fi
		fi
	done < /usr/local/etc/alcasar-services
	# Rejet explicite (vers le LAN) des autres protocoles
	# reject the others
	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j ULOG --ulog-prefix "RULE F_filter -- REJECT "
	$IPTABLES -A FORWARD -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
	$IPTABLES -A FORWARD -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
	$IPTABLES -A FORWARD -i $TUNIF -p icmp -j REJECT 
fi
 
########################
#  If QOS is activate  #
########################
if [ $QOS = on ] && [ -e /usr/local/etc/alcasar-iptables-qos.sh ]; then
	. /usr/local/etc/alcasar-iptables-qos.sh 	
fi
 
# Autorisation des connections sortant du LAN  
# Allow forward connections with log
$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE F_all -- ACCEPT "
$IPTABLES -A FORWARD -i $TUNIF -m state --state NEW -j ACCEPT
 
#################################################################################################
#  Direct input from local network (icmp, dns, ntp, https, http, ssh and 3990 (user disconnect) #
#################################################################################################
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 0 -j ACCEPT # ping reply
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p icmp --icmp-type 8 -j ACCEPT # ping request
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport domain -j ACCEPT # dnsmasq without forward
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport 54 -j ACCEPT # dnsmasq with blackhole
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p udp --dport ntp -j ACCEPT
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport https -j ACCEPT
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport http -j ACCEPT
$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport 3990 -j ACCEPT
# SSHD rules if activate 
if [ $SSH = on ]
	then
	Admin_from_IP="0.0.0.0/0.0.0.0"		# Une @IP fixe peut-être fournie pour restreindre l'accès en ssh depuis l'extérieur (ex: 80.22.21.53/24) ( 0.0.0.0/0.0.0.0  = de n'importe où ! )
	$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport ssh -m state --state NEW -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-LAN -- ACCEPT"
	$IPTABLES -A INPUT -i $TUNIF -d $PRIVATE_IP -p tcp --dport ssh -j ACCEPT
	$IPTABLES -A INPUT -i $EXTIF -p tcp --dport ssh -s $Admin_from_IP -m state --state NEW --syn -j ULOG --ulog-nlgroup 2 --ulog-prefix "RULE ssh-from-WAN -- ACCEPT"
	$IPTABLES -A INPUT -i $EXTIF -p tcp --dport ssh -s $Admin_from_IP -m state --state NEW,ESTABLISHED -j ACCEPT
	$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport ssh -m state --state ESTABLISHED -j ACCEPT
fi
 
# Insertion de règles locales
# Here, we add local rules (i.e. ssh from Internet)
if [ -f /usr/local/etc/alcasar-iptables-local.sh ]; then
        . /usr/local/etc/alcasar-iptables-local.sh
fi
 
# On autorise les retours de connexions légitimes par INPUT
# Conntrack on INPUT
$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
 
# On interdit les connexions directes au port utilisé par DansGuardian (8080)
# Les packets concernés ont fait l'objet d'un marquage dans la table mangle 
# lors d'une règle de PREROUTING (voir plus bas)
# Deny direct connections on DansGuardian port (8080)
# The concerned paquets are marked by a pre-routing rule (see further)
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m mark --mark 1 -j DROP
# Autorisation des connexions à DansGuardian 
# Allow connections for DansGuardian
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m state --state NEW --syn -j ACCEPT
 
# Journalisation des requètes HTTP (seulement des paquets SYN)
# Log HTTP requests (only syn)
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp ! -d $PRIVATE_IP --dport http -m state --state NEW -j ULOG --ulog-prefix "RULE F_http -- ACCEPT "
# On redirige les requêtes HTTP vers DansGuardian (transparent pour les utilisateurs)
# Redirect HTTP request in DansGuardian (transparent proxy)
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp ! -d $PRIVATE_IP --dport http -j REDIRECT --to-port 8080
# Journalisation et marquage des paquets qui tentent d'accéder directement à DansGuardian 
# pour pouvoir les supprimer en INPUT (voir plus haut)
# Mark the dansguardian bypass attempts
$IPTABLES -A PREROUTING -t nat -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j ULOG --ulog-prefix "RULE direct-proxy -- DENY "
$IPTABLES -A PREROUTING -t mangle -i $TUNIF -p tcp -d $PRIVATE_IP -m tcp --dport 8080 -j MARK --set-mark 1
 
# Journalisation et rejet des connexions (autres que celles autorisées) effectuées depuis le LAN
# Deny and log on INPUT from the LAN
$IPTABLES -A INPUT -i $TUNIF -m state --state NEW -j ULOG --ulog-prefix "RULE rej-int -- REJECT "
$IPTABLES -A INPUT -i $TUNIF -p tcp -j REJECT --reject-with tcp-reset
$IPTABLES -A INPUT -i $TUNIF -p udp -j REJECT --reject-with icmp-port-unreachable
 
# Journalisation et rejet des connexions initiées depuis le réseau extérieur (test des effets du paramètre --limit en cours)
# On EXTIF, the access attempts are log in channel 2 (we should test --limit option to avoid deny of service)
$IPTABLES -A INPUT -i $EXTIF -m state --state NEW -j ULOG --ulog-nlgroup 3 --ulog-qthreshold 10 --ulog-prefix "RULE rej-ext -- DROP"
 
#############################
# filtering outside OUTPUT. #
#############################
# On laisse tout sortir sur toutes les cartes sauf celle qui est connectée sur l'extérieur
# Everything is allowed but traffic through outside network interface
$IPTABLES -A OUTPUT ! -o $EXTIF -j ACCEPT
 
# On autorise les requêtes DNS vers les serveurs DNS identifiés 
# Allow DNS requests to identified DNS servers
$IPTABLES -A OUTPUT -o $EXTIF -d $DNSSERVERS -p udp --dport domain -m state --state NEW -j ACCEPT
# On autorise les requêtes HTTP sortantes
# HTTP requests are allowed
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport http -j ACCEPT
# On autorise les requêtes NTP 
# NTP requests are allowed
$IPTABLES -A OUTPUT -o $EXTIF -p udp --dport ntp -j ACCEPT
# On autorise les requêtes ICMP (ping) 
# ICMP (ping) requests are allowed
$IPTABLES -A OUTPUT -o $EXTIF -p icmp --icmp-type 8 -j ACCEPT
# On autorise les requêtes LDAP si un serveur externe est configué
# LDAP requests are allowed if an external server is declared
if [ $LDAP = on ]
	then
	$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport ldap -j ACCEPT
	$IPTABLES -A OUTPUT -o $EXTIF -p udp --dport ldap -j ACCEPT
fi
# Traduction dynamique d'adresse en sortie
# Dynamic NAT on EXTIF
$IPTABLES -A POSTROUTING -t nat -o $EXTIF -j MASQUERADE
 
# Save all rules
/etc/init.d/iptables save
 
# End of script
 
 
Subversion Repositories ALCASAR

(root)/scripts/alcasar-iptables.sh @ 1157 – Rev 675 → 688
