#!/bin/sh
#
#     tiger - A UN*X security checking system
#     Copyright (C) 2002 Javier Fernandez-Sanguino 
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2, or (at your option)
#    any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#     Please see the file `COPYING' for the complete copyright notice.
#
# check_network_config: checks for security configuration paramenters of the
#                network environment (using /proc)
#
# 11/25/2002 jfs - Initial version derived from Hispasec's bulletin
#                  (which is based on documentation online)
# 15/04/2003 jfs - Changed ERROR into FAIL
# 10/15/2003 jfs - Return '1' instead of '-1' (Debian bug #215891)
# 04/16/2005 jfs - Fixed check of ICMP redirects (Debian bug #304957).
#                  Also fixed call to message so that everything appears
#                  in one line.
# 04/17/2005 jfs - Added check for local firewall rules
#
# References:
# http://www.linuxsecurity.com/articles/network_security_article-4528.html
# http://linux.oreillynet.com/pub/a/linux/2000/11/16/LinuxAdmin.html
# 
#-----------------------------------------------------------------------------
# TODO
# 
# - Check if conf/all have the same information as conf/default, conf/ethX...
#   (since a given interface might be different from the others)
#
#-----------------------------------------------------------------------------
#
TigerInstallDir="/usr/share/tiger"

#
# Set default base directory.
# Order or preference:
#      -B option
#      TIGERHOMEDIR environment variable
#      TigerInstallDir installed location
#
basedir=${TIGERHOMEDIR:=$TigerInstallDir}

for parm
do
   case $parm in
   -B) basedir=$2; break;;
   esac
done
#
# Verify that a config file exists there, and if it does
# source it.
#
[ ! -r $basedir/config ] && {
  echo "--ERROR-- [init002e] No 'config' file in \`$basedir'."
  exit 1
}
. $basedir/config

. $BASEDIR/initdefs
#
# If run in test mode (-t) this will verify that all required
# elements are set.
#
[ "$Tiger_TESTMODE" = 'Y' ] && {
  haveallcmds CAT || exit 1
  haveallfiles PROCDIR BASEDIR WORKDIR || exit 1
  
  echo "--CONFIG-- [init003c] $0: Configuration ok..."
  exit 0
}
#------------------------------------------------------------------------
haveallcmds CAT || exit 1
haveallfiles BASEDIR WORKDIR || exit 1
haveallfiles PROCDIR || {
        message ERROR lin008e "" "The $PROCDIR filesystem is not available. Please make sure you have configured support for this pseudo-filesystem."
	exit 1
}
echo
echo "# Checking network configuration"

# Instead of using the sysctl interface we are going to $CAT from the
# specified locations

read_if_exist() {
# Reads a file if it exists
# Otherwise returns 1
	file=$1
	value=1
	[ -f $1 ] && value=`$CAT $file`
	return $value
}

read_if_exist /proc/sys/net/ipv4/icmp_echo_ignore_all
icmp_echo_ignore=$?
read_if_exist /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
icmp_broadcast_ignore=$?
read_if_exist /proc/sys/net/ipv4/icmp_bogus_error_responses
icmp_bogus_error=$?
read_if_exist /proc/sys/net/ipv4/conf/all/accept_redirects
icmp_redirect=$?
read_if_exist /proc/sys/net/ipv4/conf/default/accept_redirects
icmp_redirect_def=$?
read_if_exist /proc/sys/net/ipv4/tcp_syncookies
tcp_syncookies=$?
read_if_exist /proc/sys/net/ipv4/conf/all/rp_filter
rp_filter_all=$?
read_if_exist /proc/sys/net/ipv4/default/all/rp_filter
rp_filter_def=$?
read_if_exist /proc/sys/net/ipv4/ip_forward
ip_fwd=$?
read_if_exist /proc/sys/net/ipv4/conf/all/accept_source_route
ip_source_route_all=$?
read_if_exist /proc/sys/net/ipv4/conf/default/accept_source_route
ip_source_route_def=$?
read_if_exist /proc/sys/net/ipv4/conf/all/log_martians
log_martian_all=$?
read_if_exist /proc/sys/net/ipv4/conf/default/log_martians
log_martian_def=$?
# Only useful for kernel's 2.2 and previous
read_if_exist /proc/sys/net/ipv4/conf/all/hidden
ip_weak_end=$?

# Aff info on this
read_if_exist /proc/sys/net/ipv4/ip_always_defrag
ip_always_defrag=$?
read_if_exist /proc/sys/net/ipv4/conf/all/bootp_relay
bootp_relay=$?
read_if_exist /proc/sys/net/ipv4/conf/all/mc_forwarding
mc_forwarding=$?
read_if_exist /proc/sys/net/ipv4/conf/all/proxy_arp
proxy_arp=$?
read_if_exist /proc/sys/net/ipv4/conf/all/secure_redirects
secure_redirects=$?

# Now start checking and sending messages

[ $icmp_echo_ignore -eq 0 ] && \
	message INFO lin009i "" "The system is configured to answer ICMP ECHO requests"
[ $icmp_broadcast_ignore -eq 0 ] && \
	message FAIL lin010f "" "The system is configured to answer to ICMP broadcasts"
[ $icmp_bogus_error -eq 0 ] && \
	message FAIL lin011f "" "The system is configured to answer bogus errors"

[ $icmp_redirect -eq 1 -o $icmp_redirect_def -eq 1 ] && \
	message WARN lin012w "" "The system accepts ICMP redirection messages"

[ $tcp_syncookies -eq 0 ] && \
	message FAIL lin013f "" "The system is not protected against Syn flooding attacks"

[ $rp_filter_all -eq 0 -o $rp_filter_def -eq 0 ] && \
	message FAIL lin014f "" "The system permits the transmission of IP packets with invalid addresses"

[ $ip_fwd -eq 1 ]  && \
	message WARN lin015w "" "The system has IP forwarding enabled"

[ $ip_source_route_all -eq 1 -o $ip_source_route_def -eq 1 ] && \
	message FAIL lin016f "" "The system permits source routing from incoming packets"

[ $log_martian_all -eq 0 -o $log_martian_def -eq 0 ] && \
	message WARN lin017w "" "The system is not configured to log suspicious (martian) packets"

# TODO: add a test that is useful for post-2.2 kernels
[ $ip_weak_end -eq 0 ] && \
	message WARN lin018w "" "The system implements weak end host RFC"

# Check if there is (at least) and 

haveallcmds CMP IPTABLES && {
	iptablesrules=$WORKDIR/ipt.$$
	iptablesempty=$WORKDIR/iptempt.$$
	safe_temp $iptablesrules $iptablesempty
	trap 'delete $iptablesrules $iptablesempty; exit 1;' 1 2 3 15
	
	$IPTABLES -nL 2>/dev/null >>$iptablesrules
	if [ -s "$iptablesrules" ]; then
		$CAT >>$iptablesempty <<EOF
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
EOF
		$CMP -s $iptablesrules $iptablesempty 
		[ $? -eq 0 ] && message FAIL lin019f "" "The system does not have any local firewall rules configured"
	else
		message ERROR run002e "" "Cannot extract local firewalling rules running $IPTABLES"
	fi
	delete $iptablesrules $iptablesempty
}

exit 0
