bpfire/src/initscripts/system/firewall

#!/bin/sh

. /etc/sysconfig/rc
. ${rc_functions}

eval $(/usr/local/bin/readhash /var/ipfire/ppp/settings)
eval $(/usr/local/bin/readhash /var/ipfire/ethernet/settings)
eval $(/usr/local/bin/readhash /var/ipfire/optionsfw/settings)
IFACE=`/bin/cat /var/ipfire/red/iface 2> /dev/null | /usr/bin/tr -d '\012'`

if [ -f /var/ipfire/red/device ]; then
	DEVICE=`/bin/cat /var/ipfire/red/device 2> /dev/null | /usr/bin/tr -d '\012'`
fi

NAT_MASK="0x0f000000"

IPS_REPEAT_MARK="0x80000000"
IPS_REPEAT_MASK="0x80000000"
IPS_BYPASS_MARK="0x40000000"
IPS_BYPASS_MASK="0x40000000"

function iptables() {
	/sbin/iptables --wait "$@"
}

iptables_init() {
	# Flush all rules and delete all custom chains
	iptables -F
	iptables -t nat -F
	iptables -t mangle -F
	iptables -t raw -F
	iptables -X
	iptables -t nat -X
	iptables -t mangle -X
	iptables -t raw -X

	# Set up policies
	iptables -P INPUT DROP
	iptables -P FORWARD DROP
	iptables -P OUTPUT ACCEPT

	# Ensure the xt_geoip module is always loaded (#12767)
	modprobe xt_geoip

	# Enable TRACE logging to syslog
	modprobe nf_log_ipv4
	sysctl -q -w net.netfilter.nf_log.2=nf_log_ipv4

	# IPS Bypass Chain which stores the BYPASS bit in connection tracking
	iptables -N IPSBYPASS
	iptables -A IPSBYPASS -j CONNMARK --save-mark --mask "$(( ~IPS_REPEAT_MASK & 0xffffffff ))"

	# Jump into bypass chain when the BYPASS bit is set
	for chain in INPUT FORWARD OUTPUT; do
		iptables -A "${chain}" -m mark \
			--mark "$(( IPS_REPEAT_MARK | IPS_BYPASS_MARK ))/$(( IPS_REPEAT_MASK | IPS_BYPASS_MASK ))" -j IPSBYPASS
	done

	# Empty LOG_DROP and LOG_REJECT chains
	iptables -N LOG_DROP
	iptables -A LOG_DROP   -m limit --limit 10/second -j LOG
	iptables -A LOG_DROP   -j DROP
	iptables -N LOG_REJECT
	iptables -A LOG_REJECT -m limit --limit 10/second -j LOG
	iptables -A LOG_REJECT -j REJECT

	# This chain will log, then DROPs packets with certain bad combinations
	# of flags might indicate a port-scan attempt (xmas, null, etc.)
	iptables -N PSCAN
	if [ "$DROPPORTSCAN" == "on" ]; then
		iptables -A PSCAN -p tcp  -m limit --limit 10/second -j LOG --log-prefix "DROP_TCP Scan "  -m comment --comment "DROP_TCP PScan"
		iptables -A PSCAN -p udp  -m limit --limit 10/second -j LOG --log-prefix "DROP_UDP Scan "  -m comment --comment "DROP_UDP PScan"
		iptables -A PSCAN -p icmp -m limit --limit 10/second -j LOG --log-prefix "DROP_ICMP Scan " -m comment --comment "DROP_ICMP PScan"
		iptables -A PSCAN -f      -m limit --limit 10/second -j LOG --log-prefix "DROP_FRAG Scan " -m comment --comment "DROP_FRAG PScan"
	fi
	iptables -A PSCAN -j DROP -m comment --comment "DROP_PScan"

	# New tcp packets without SYN set - could well be an obscure type of port scan
	# that's not covered above, may just be a broken Windows machine
	iptables -N NEWNOTSYN
	if [ "$DROPNEWNOTSYN" == "on" ]; then
		iptables -A NEWNOTSYN  -m limit --limit 10/second -j LOG  --log-prefix "DROP_NEWNOTSYN "
	fi
	iptables -A NEWNOTSYN  -j DROP -m comment --comment "DROP_NEWNOTSYN"

	# Log and subsequently drop spoofed packets or "martians", arriving from sources
	# on interfaces where we don't expect them
	iptables -N SPOOFED_MARTIAN
	if [ "$DROPSPOOFEDMARTIAN" == "on" ]; then
		iptables -A SPOOFED_MARTIAN  -m limit --limit 10/second -j LOG  --log-prefix "DROP_SPOOFED_MARTIAN "
	fi
	iptables -A SPOOFED_MARTIAN -j DROP -m comment --comment "DROP_SPOOFED_MARTIAN"

	# Chain to contain all the rules relating to bad TCP flags
	iptables -N BADTCP

	# Don't check loopback
	iptables -A BADTCP -i lo -j RETURN

	# Disallow packets frequently used by port-scanners
	# NMAP FIN/URG/PSH (XMAS scan)
	iptables -A BADTCP -p tcp --tcp-flags ALL FIN,URG,PSH -j PSCAN
	# SYN/RST/ACK/FIN/URG
	iptables -A BADTCP -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j PSCAN
	# ALL/ALL
	iptables -A BADTCP -p tcp --tcp-flags ALL ALL -j PSCAN
	# FIN Stealth
	iptables -A BADTCP -p tcp --tcp-flags ALL FIN -j PSCAN
	# SYN/RST (also catches xmas variants that set SYN+RST+...)
	iptables -A BADTCP -p tcp --tcp-flags SYN,RST SYN,RST -j PSCAN
	# SYN/FIN (QueSO or nmap OS probe)
	iptables -A BADTCP -p tcp --tcp-flags SYN,FIN SYN,FIN -j PSCAN
	# Null
	iptables -A BADTCP -p tcp --tcp-flags ALL NONE -j PSCAN
	# NEW TCP without SYN
	iptables -A BADTCP -p tcp ! --syn -m conntrack --ctstate NEW -j NEWNOTSYN

	iptables -A INPUT   -p tcp -j BADTCP
	iptables -A FORWARD -p tcp -j BADTCP

	# Connection tracking chains
	iptables -N CONNTRACK
	iptables -A CONNTRACK -m conntrack --ctstate ESTABLISHED -j ACCEPT
	iptables -A CONNTRACK -m conntrack --ctstate INVALID -j LOG_DROP
	iptables -A CONNTRACK -p icmp -m conntrack --ctstate RELATED -j ACCEPT

	# Restore any connection marks
	iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark

	# Fix for braindead ISPs
	iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu

	# CUSTOM chains, can be used by the users themselves
	iptables -N CUSTOMINPUT
	iptables -A INPUT -j CUSTOMINPUT
	iptables -N CUSTOMFORWARD
	iptables -A FORWARD -j CUSTOMFORWARD
	iptables -N CUSTOMOUTPUT
	iptables -A OUTPUT -j CUSTOMOUTPUT
	iptables -t nat -N CUSTOMPREROUTING
	iptables -t nat -A PREROUTING -j CUSTOMPREROUTING
	iptables -t nat -N CUSTOMPOSTROUTING
	iptables -t nat -A POSTROUTING -j CUSTOMPOSTROUTING

	# Log and drop any traffic from and to networks known as being hostile, posing
	# a technical threat to our users (i. e. listed at Spamhaus DROP et al.)
	iptables -N HOSTILE
	if [ "$DROPHOSTILE" == "on" ]; then
		iptables -A HOSTILE -m limit --limit 10/second -j LOG  --log-prefix "DROP_HOSTILE "
		iptables -A INPUT   -i $IFACE -m geoip --src-cc XD -j HOSTILE
		iptables -A FORWARD -i $IFACE -m geoip --src-cc XD -j HOSTILE
		iptables -A FORWARD -o $IFACE -m geoip --dst-cc XD -j HOSTILE
		iptables -A OUTPUT  -o $IFACE -m geoip --src-cc XD -j HOSTILE
	fi
	iptables -A HOSTILE -j DROP -m comment --comment "DROP_HOSTILE"

	# P2PBLOCK
	iptables -N P2PBLOCK
	iptables -A INPUT -j P2PBLOCK
	iptables -A FORWARD -j P2PBLOCK
	iptables -A OUTPUT -j P2PBLOCK

	# IPS (Guardian) chains
	iptables -N GUARDIAN
	iptables -A INPUT -j GUARDIAN
	iptables -A FORWARD -j GUARDIAN

	# Block non-established IPsec networks
	iptables -N IPSECBLOCK
	iptables -A FORWARD -m policy --dir out --pol none -j IPSECBLOCK
	iptables -A OUTPUT  -m policy --dir out --pol none -j IPSECBLOCK

	# Block OpenVPN transfer networks
	iptables -N OVPNBLOCK
	iptables -A INPUT   -i tun+ -j OVPNBLOCK
	iptables -A FORWARD -i tun+ -j OVPNBLOCK
	iptables -A FORWARD -o tun+ -j OVPNBLOCK

	# IPS (Suricata) chains
	iptables -N IPS_INPUT
	iptables -N IPS_FORWARD
	iptables -N IPS_OUTPUT

	for chain in INPUT FORWARD OUTPUT; do
		iptables -A "${chain}" -m mark --mark "0x0/$(( IPS_REPEAT_MASK | IPS_BYPASS_MASK ))" -j "IPS_${chain}"
	done

	# OpenVPN transfer network translation
	iptables -t nat -N OVPNNAT
	iptables -t nat -A POSTROUTING -j OVPNNAT

	# IPTV chains for IGMPPROXY
	iptables -N IPTVINPUT
	iptables -A INPUT -j IPTVINPUT
	iptables -N IPTVFORWARD
	iptables -A FORWARD -j IPTVFORWARD

	# Allow to ping the firewall.
	iptables -N ICMPINPUT
	iptables -A INPUT -j ICMPINPUT
	iptables -A ICMPINPUT -p icmp --icmp-type 8 -j ACCEPT

	# Accept everything on loopback if source/destination is loopback space...
	iptables -N LOOPBACK
	iptables -A LOOPBACK -i lo -s 127.0.0.0/8 -j ACCEPT
	iptables -A LOOPBACK -o lo -d 127.0.0.0/8 -j ACCEPT

	# ... and drop everything else on the loopback interface, since no other traffic should appear there
	iptables -A LOOPBACK -i lo -j SPOOFED_MARTIAN
	iptables -A LOOPBACK -o lo -j SPOOFED_MARTIAN

	# Filter all packets with loopback addresses on non-loopback interfaces (spoofed)
	iptables -A LOOPBACK -s 127.0.0.0/8 -j SPOOFED_MARTIAN
	iptables -A LOOPBACK -d 127.0.0.0/8 -j SPOOFED_MARTIAN

	for i in INPUT FORWARD OUTPUT; do
		iptables -A ${i} -j LOOPBACK
	done

	# Captive portal
	iptables -N CAPTIVE_PORTAL
	iptables -N CAPTIVE_PORTAL_CLIENTS
	for i in INPUT FORWARD; do
		iptables -A ${i} -j CAPTIVE_PORTAL
	done

	# Accept everything connected
	for i in INPUT FORWARD OUTPUT; do
		iptables -A ${i} -j CONNTRACK
	done

	# Allow DHCP
	iptables -N DHCPINPUT
	iptables -A DHCPINPUT -p udp --sport 68 --dport 67 -j ACCEPT
	iptables -A DHCPINPUT -p tcp --sport 68 --dport 67 -j ACCEPT

	iptables -N DHCPOUTPUT
	iptables -A DHCPOUTPUT -p udp --sport 67 --dport 68 -j ACCEPT
	iptables -A DHCPOUTPUT -p tcp --sport 67 --dport 68 -j ACCEPT

	# Allow DHCP on GREEN
	iptables -N DHCPGREENINPUT
	iptables -N DHCPGREENOUTPUT
	if [ -n "${GREEN_DEV}" ]; then
		iptables -A INPUT  -i "${GREEN_DEV}" -j DHCPGREENINPUT
		iptables -A OUTPUT -o "${GREEN_DEV}" -j DHCPGREENOUTPUT
	fi

	# Allow DHCP on BLUE to be turned on/off
	iptables -N DHCPBLUEINPUT
	iptables -N DHCPBLUEOUTPUT
	if [ -n "${BLUE_DEV}" ]; then
		iptables -A INPUT  -i "${BLUE_DEV}" -j DHCPBLUEINPUT
		iptables -A OUTPUT -o "${BLUE_DEV}" -j DHCPBLUEOUTPUT
	fi

	# Tor (inbound)
	iptables -N TOR_INPUT
	iptables -A INPUT -j TOR_INPUT

	# Location Block
	iptables -N LOCATIONBLOCK
	iptables -A INPUT -j LOCATIONBLOCK
	iptables -A FORWARD -j LOCATIONBLOCK

	# trafic from ipsecX/TUN/TAP interfaces, before "-i GREEN_DEV" accept everything
	iptables -N IPSECINPUT
	iptables -N IPSECFORWARD
	iptables -N IPSECOUTPUT
	iptables -A INPUT -j IPSECINPUT
	iptables -A FORWARD -j IPSECFORWARD
	iptables -A OUTPUT -j IPSECOUTPUT
	iptables -t nat -N IPSECNAT
	iptables -t nat -A POSTROUTING -j IPSECNAT

	# localhost and ethernet.
	# Always allow accessing the web GUI from GREEN.
	iptables -N GUIINPUT
	iptables -A INPUT -j GUIINPUT
	if [ -n "${GREEN_DEV}" ]; then
		iptables -A GUIINPUT -i "${GREEN_DEV}" -p tcp --dport 444 -j ACCEPT
	fi

	# WIRELESS chains
	iptables -N WIRELESSINPUT
	iptables -A INPUT -m conntrack --ctstate NEW -j WIRELESSINPUT
	iptables -N WIRELESSFORWARD
	iptables -A FORWARD -m conntrack --ctstate NEW -j WIRELESSFORWARD

	# OpenVPN
	iptables -N OVPNINPUT
	iptables -A INPUT -j OVPNINPUT

	# Tor (outbound)
	iptables -N TOR_OUTPUT
	iptables -A OUTPUT -j TOR_OUTPUT

	# Jump into the actual firewall ruleset.
	iptables -N INPUTFW
	iptables -A INPUT -j INPUTFW

	iptables -N OUTGOINGFW
	iptables -A OUTPUT -j OUTGOINGFW

	iptables -N FORWARDFW
	iptables -A FORWARD -j FORWARDFW

	# SNAT rules
	iptables -t nat -N NAT_SOURCE
	iptables -t nat -A POSTROUTING -j NAT_SOURCE

	# Captive Portal
	iptables -t nat -N CAPTIVE_PORTAL
	iptables -t nat -A PREROUTING -j CAPTIVE_PORTAL

	# Custom prerouting chains (for transparent proxy)
	iptables -t nat -N SQUID
	iptables -t nat -A PREROUTING -j SQUID

	# DNAT rules
	iptables -t nat -N NAT_DESTINATION
	iptables -t nat -A PREROUTING -j NAT_DESTINATION
	iptables -t nat -A OUTPUT -j NAT_DESTINATION

	iptables -t mangle -N NAT_DESTINATION
	iptables -t mangle -A PREROUTING -j NAT_DESTINATION

	iptables -t nat -N NAT_DESTINATION_FIX
	iptables -t nat -A POSTROUTING -j NAT_DESTINATION_FIX

	if [ -n "${GREEN_ADDRESS}" ]; then
		iptables -t nat -A NAT_DESTINATION_FIX \
			-m mark --mark "0x01000000/${NAT_MASK}" -j SNAT --to-source "${GREEN_ADDRESS}"
	fi

	if [ -n "${BLUE_ADDRESS}" ]; then
		iptables -t nat -A NAT_DESTINATION_FIX \
			-m mark --mark "0x02000000/${NAT_MASK}" -j SNAT --to-source "${BLUE_ADDRESS}"
	fi

	if [ -n "${ORANGE_ADDRESS}" ]; then
		iptables -t nat -A NAT_DESTINATION_FIX \
			-m mark --mark "0x04000000/${NAT_MASK}" -j SNAT --to-source "${ORANGE_ADDRESS}"
	fi

	# RED chain, used for the red interface
	iptables -N REDINPUT
	iptables -A INPUT -j REDINPUT
	iptables -N REDFORWARD
	iptables -A FORWARD -j REDFORWARD
	iptables -t nat -N REDNAT
	iptables -t nat -A POSTROUTING -j REDNAT

	# Populate IPsec chains
	/usr/lib/firewall/ipsec-policy

	# Apply OpenVPN firewall rules
	/usr/local/bin/openvpnctrl --firewall-rules

	# run wirelessctrl
	/usr/local/bin/wirelessctrl

	# run captivectrl
	/usr/local/bin/captivectrl

	# POLICY CHAIN
	iptables -N POLICYIN
	iptables -A INPUT -j POLICYIN
	iptables -N POLICYFWD
	iptables -A FORWARD -j POLICYFWD
	iptables -N POLICYOUT
	iptables -A OUTPUT -j POLICYOUT

	# Initialize firewall policies.
	/usr/sbin/firewall-policy

	# Install firewall rules for the red interface.
	iptables_red_up

	# If red has not been brought up yet, we will
	# add the blocking rules for MASQUERADE
	if [ ! -e "/var/ipfire/red/active" ]; then
		iptables_red_down
	fi
}

iptables_red_up() {
	iptables -F REDINPUT
	iptables -F REDFORWARD
	iptables -t nat -F REDNAT

	# Prohibit spoofing our own IP address on RED
	if [ -f /var/ipfire/red/active ]; then
		REDIP="$( cat /var/ipfire/red/local-ipaddress )";

		if [ "$IFACE" != "" ]; then
			iptables -A REDINPUT -s $REDIP -i $IFACE -j SPOOFED_MARTIAN
		elif [ "$DEVICE" != "" ]; then
			iptables -A REDINPUT -s $REDIP -i $DEVICE -j SPOOFED_MARTIAN
		fi
	fi

	# PPPoE / PPTP Device
	if [ "$IFACE" != "" ]; then
		# PPPoE / PPTP
		if [ "$DEVICE" != "" ]; then
			iptables -A REDINPUT -i $DEVICE -j ACCEPT
		fi
		if [ "$RED_TYPE" == "PPTP" -o "$RED_TYPE" == "PPPOE" ]; then
			if [ "$RED_DEV" != "" ]; then
				iptables -A REDINPUT -i $RED_DEV -j ACCEPT
			fi
		fi
	fi

	# PPTP over DHCP
	if [ "$DEVICE" != "" -a "$TYPE" == "PPTP" -a "$METHOD" == "DHCP" ]; then
		iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
		iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $DEVICE -j ACCEPT
	fi

	if [ "$IFACE" != "" -a -f /var/ipfire/red/active ]; then
		# DHCP
		if [ "$RED_DEV" != "" -a "$RED_TYPE" == "DHCP" ]; then
			iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
			iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
		fi
		if [ "$METHOD" == "DHCP"  -a "$PROTOCOL" == "RFC1483" ]; then
			iptables -A REDINPUT -p tcp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
			iptables -A REDINPUT -p udp --source-port 67 --destination-port 68 -i $IFACE -j ACCEPT
		fi

		# Outgoing masquerading (don't masqerade IPsec)
		iptables -t nat -A REDNAT -m policy --pol ipsec --dir=out -o "${IFACE}" -j RETURN

		if [ "${IFACE}" = "${GREEN_DEV}" ]; then
			iptables -t nat -A REDNAT -i "${GREEN_DEV}" -o "${IFACE}" -j RETURN
		fi

		local NO_MASQ_NETWORKS

		if [ "${MASQUERADE_GREEN}" = "off" ]; then
			NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${GREEN_NETADDRESS}/${GREEN_NETMASK}"
		fi

		if [ "${MASQUERADE_BLUE}" = "off" ]; then
			NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${BLUE_NETADDRESS}/${BLUE_NETMASK}"
		fi

		if [ "${MASQUERADE_ORANGE}" = "off" ]; then
			NO_MASQ_NETWORKS="${NO_MASQ_NETWORKS} ${ORANGE_NETADDRESS}/${ORANGE_NETMASK}"
		fi

		local network
		for network in ${NO_MASQ_NETWORKS}; do
			iptables -t nat -A REDNAT -s "${network}" -o "${IFACE}" -j RETURN
		done

		# Masquerade everything else
		iptables -t nat -A REDNAT -o $IFACE -j MASQUERADE
	fi

	# Reload all rules.
	/usr/local/bin/firewallctrl
}

iptables_red_down() {
	# Prohibit packets to reach the masquerading rule
	# while the WAN interface is down - this is required to
	# circumvent udp related NAT issues
	# http://forum.ipfire.org/index.php?topic=11127.0
	if [ -n "${IFACE}" ]; then
		iptables -F REDFORWARD
		iptables -A REDFORWARD -o "${IFACE}" -j DROP
	fi

	# Reload all rules.
	/usr/local/bin/firewallctrl
}

# See how we were called.
case "$1" in
  start)
	boot_mesg "Setting up firewall"
	iptables_init
	evaluate_retval
	;;
  reload|up)
	boot_mesg "Reloading firewall"
	iptables_red_up
	evaluate_retval
	;;
  down)
	boot_mesg "Disabling firewall access to RED"
	iptables_red_down
	evaluate_retval
	;;
  restart)
	$0 start
	;;
  *)
        echo "Usage: $0 {start|reload|restart}"
        exit 1
	;;
esac

exit 0