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#!/bin/bash
# $Id: alcasar-iptables.sh 1072 2013-04-14 21:36:57Z 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 'this 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_IP=`echo $private_ip_mask | cut -d"/" -f1` # ALCASAR LAN IP address
private_network=`/bin/ipcalc -n $private_ip_mask|cut -d"=" -f2` # LAN IP address (ie.: 192.168.182.0)
private_prefix=`/bin/ipcalc -p $private_ip_mask|cut -d"=" -f2` # LAN prefix (ie. 24)
PRIVATE_NETWORK_MASK=$private_network/$private_prefix # Lan IP address + prefix (192.168.182.0/24)
public_ip_mask=`grep PUBLIC_IP= $conf_file|cut -d"=" -f2` # ALCASAR WAN IP address
PUBLIC_IP=`echo $public_ip_mask | cut -d"/" -f1`
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}
DNSSERVERS="$dns1,$dns2" # first and second DNS IP servers addresses
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}
BL_IP_CAT="/usr/local/share/iptables-bl-enabled" # categories files of the BlackListed IP
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}
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)
LDAP=`grep LDAP= $conf_file|cut -d"=" -f2` # LDAP external server active (on/off)
LDAP=${LDAP:=off}
LDAP_IP=`grep LDAP_IP= $conf_file|cut -d"=" -f2` # WAN IP address to reduce LDAP WAN access (all ip allowed on LAN side)
LDAP_IP=${LDAP_IP:="0.0.0.0/0.0.0.0"}
EXTIF="eth0"
INTIF="eth1"
TUNIF="tun0" # listen device 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
#############################
# PREROUTING #
#############################
# Marquage (et journalisation) des paquets qui tentent d'accéder directement à DansGuardian pour pouvoir les rejeter en INPUT
# mark (and log) the dansguardian bypass attempts in order to DROP them in INPUT rules
# $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 -d $PRIVATE_IP -p tcp -m tcp --dport 8080 -j MARK --set-mark 1
# Marquage (et journalisation) des paquets qui tentent d'accéder directement au port udp 54 pour pouvoir les rejeter en INPUT
# Mark (and log) the udp 54 direct attempts to REJECT them in INPUT rules
# Remarque : Ce port n'est ouvert que lorsque le filtrage est activé
# Remark : this port is only open when filtering is on
# $IPTABLES -A PREROUTING -t nat -i $TUNIF -p udp -d $PRIVATE_IP -m udp --dport 54 -j ULOG --ulog-prefix "RULE DNS-proxy -- DENY "
$IPTABLES -A PREROUTING -t mangle -i $TUNIF -d $PRIVATE_IP -p tcp --dport 54 -j MARK --set-mark 2
# Si le filtrage DNS est activé, redirection des flux DNS vers le port 54 (dns+blackhole) sauf pour les IP en exceptions
# If DNS filter is on, redirect DNS request to udp 54 (dns+blackhole) except for exception IP addresses
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 -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j REDIRECT --to-port 54
fi
# Journalisation des requètes HTTP vers Internet (seulement les paquets SYN) - Les autres protocoles sont journalisés en FORWARD
# Log HTTP requests to Internet (only syn packets) - Other protocols are log in FORWARD
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p tcp --dport http -m state --state NEW -j ULOG --ulog-prefix "RULE F_http -- ACCEPT "
# Redirection des requêtes HTTP vers DansGuardian (proxy transparent)
# Redirect HTTP requests in DansGuardian (transparent proxy)
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p tcp --dport http -j REDIRECT --to-port 8080
# Redirection des requêtes NTP vers le serveur NTP local
# Redirect NTP request in local NTP server
$IPTABLES -A PREROUTING -t nat -i $TUNIF -s $PRIVATE_NETWORK_MASK ! -d $PRIVATE_IP -p udp --dport ntp -j REDIRECT --to-port 123
#############################
# INPUT #
#############################
# Tout passe sur loopback
# accept all on loopback
$IPTABLES -A INPUT -i lo -j ACCEPT
$IPTABLES -A OUTPUT -o lo -j ACCEPT
# Rejet des demandes de connexions non conformes (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)
# Drop non standard connexions (FIN-URG-PUSH, XMAS, NullScan, SYN-RST et NEW not SYN)
$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 rejette les trame en broadcast et en multicast sur EXTIF (évite leur journalisation)
# Drop broadcast & multicast on EXTIF to avoid log
$IPTABLES -A INPUT -i $EXTIF -m addrtype --dst-type BROADCAST,MULTICAST -j DROP
# 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 été marqués dans la table mangle (PREROUTING)
# Deny direct connections on DansGuardian port (8080). The concerned paquets are marked in mangle table (PREROUTING)
$IPTABLES -A INPUT -i $TUNIF -p tcp --dport 8080 -m mark --mark 1 -j REJECT --reject-with tcp-reset
# Insertion des règles de blocage IP
# Here, we add IP block rules
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 INPUT -i $TUNIF -d $ip_blocked -p tcp --dport 8080 -m state --state NEW --syn -j ULOG --ulog-prefix "RULE IP-blocked -- REJECT "
$IPTABLES -A INPUT -i $TUNIF -d $ip_blocked -p tcp --dport 8080 -m state --state NEW --syn -j REJECT
fi
done < /usr/local/etc/alcasar-ip-blocked
fi
# Autorisation des connexions légitimes à DansGuardian
# Allow connections for DansGuardian
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport 8080 -m state --state NEW --syn -j ACCEPT
# On interdit les connexions directes au port UDP 54. Les packets concernés ont été marqués dans la table mangle (PREROUTING)
# Deny direct connections on UDP 54. The concerned paquets are marked in mangle table (PREROUTING)
$IPTABLES -A INPUT -i $TUNIF -p udp --dport 54 -m mark --mark 2 -j REJECT --reject-with icmp-port-unreachable
# autorisation des connexion légitime à DNSMASQ (avec blackhole)
# Allow connections for DNSMASQ (with blackhole)
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport 54 -j ACCEPT
# Accès direct aux services internes
# Internal services access
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport domain -j ACCEPT # DNS non filtré # DNS without blackhole
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p icmp --icmp-type 8 -j ACCEPT # Réponse ping # ping responce
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p icmp --icmp-type 0 -j ACCEPT # Requête ping # ping request
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport https -j ACCEPT # Pages d'authentification et MCC # authentication pages and MCC
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport http -j ACCEPT # Page d'avertissement filtrage # Filtering warning pages
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport 3990 -j ACCEPT # Requêtes de deconnexion usagers # Users logout requests
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p udp --dport ntp -j ACCEPT # Serveur local de temps # local time server
# SSHD rules if activate
if [ $SSH = on ]
then
$IPTABLES -A INPUT -i $TUNIF -s $PRIVATE_NETWORK_MASK -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 -s $PRIVATE_NETWORK_MASK -d $PRIVATE_IP -p tcp --dport ssh -j ACCEPT
$IPTABLES -A INPUT -i $EXTIF -s $SSH_ADMIN_FROM -d $PUBLIC_IP -p tcp --dport ssh -m state --state NEW --syn -j ULOG --ulog-nlgroup 2 --ulog-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,ESTABLISHED -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
# 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
# interdiction d'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
# 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"
#############################
# FORWARD #
#############################
# Rejet des requêtes DNS vers Internet
# Deny forward DNS
$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
# Insertion des règles de blocage IP
# Here, we add local IP block rules
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 -i $TUNIF -d $ip_blocked -j ULOG --ulog-prefix "RULE IP-blocked -- REJECT "
$IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p udp -j REJECT --reject-with icmp-port-unreachable
$IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p icmp -j REJECT --reject-with icmp-port-unreachable
$IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p tcp -j REJECT --reject-with tcp-reset
fi
done < /usr/local/etc/alcasar-ip-blocked
fi
# Si le filtrage de domain est activé, blocage des IP de la BL
# If DNS filter is on, reject IP of BL
# Comment : loading time is too long and iptables should become oveloaded !!!
#if [ $DNS_FILTERING = on ]; then
# cd $BL_IP_CAT
# for category in `ls -1 | cut -d"@" -f1`
# do
# while read ip_blocked
# do
# $IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -j ULOG --ulog-prefix "RULE IP-blocked -- REJECT "
# $IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p udp -j REJECT --reject-with icmp-port-unreachable
# $IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p icmp -j REJECT --reject-with icmp-port-unreachable
# $IPTABLES -A FORWARD -i $TUNIF -d $ip_blocked -p tcp -j REJECT --reject-with tcp-reset
# done < $BL_IP_CAT/$category
# done
#fi
# Autorisation des retours de connexions légitimes
# Allow conntrack
$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
# 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 connected between ALCASAR and Internet (DMZ, own servers, ...)
nb_uamallowed=`wc -l /usr/local/etc/alcasar-uamallowed | cut -d" " -f1`
if [ $nb_uamallowed != "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 -s $PRIVATE_NETWORK_MASK -p icmp -j ACCEPT
else
$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_TCP-$svc_name -- ACCEPT "
$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p tcp --dport $svc_port -m state --state NEW -j ACCEPT
$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p udp --dport $svc_port -m state --state NEW -j ULOG --ulog-prefix "RULE F_UDP-$svc_name -- ACCEPT "
$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -p udp --dport $svc_port -m state --state NEW -j ACCEPT
fi
fi
done < /usr/local/etc/alcasar-services
# Rejet explicite des autres protocoles
# reject the others protocols
$IPTABLES -A FORWARD -i $TUNIF -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 -s $PRIVATE_NETWORK_MASK -m state --state NEW -j ULOG --ulog-prefix "RULE F_all -- ACCEPT "
$IPTABLES -A FORWARD -i $TUNIF -s $PRIVATE_NETWORK_MASK -m state --state NEW -j ACCEPT
#############################
# OUTPUT #
#############################
# SSHD rules if activate
if [ $SSH = on ]
then
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --sport ssh -m state --state ESTABLISHED -j ACCEPT
fi
# 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 FTP
# FTP requests are allowed
modprobe ip_conntrack_ftp
$IPTABLES -A OUTPUT -o $EXTIF -p tcp --dport ftp -j ACCEPT
$IPTABLES -A OUTPUT -o $EXTIF -m state --state ESTABLISHED,RELATED -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 -p tcp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
$IPTABLES -A OUTPUT -p udp -d $LDAP_IP -m multiport --dports ldap,ldaps -m state --state NEW,ESTABLISHED -j ACCEPT
# $IPTABLES -A INPUT -p tcp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
# $IPTABLES -A INPUT -p udp -s $LDAP_IP -m multiports --sports ldap,ldaps -m state --state ESTABLISHED -j ACCEPT
fi
#############################
# POSTROUTING #
#############################
# 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