#!/bin/sh -
# Copyright (c) 1996 Poul-Henning Kamp
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
#
# Setup system for ipfw(4) firewall service.
#
# Suck in the configuration variables.
if [ -z "${source_rc_confs_defined}" ]; then
if [ -r /etc/defaults/rc.conf ]; then
. /etc/defaults/rc.conf
source_rc_confs
elif [ -r /etc/rc.conf ]; then
. /etc/rc.conf
fi
fi
############
# Define the firewall type in /etc/rc.conf. Valid values are:
# open - will allow anyone in
# client - will try to protect just this machine
# simple - will try to protect a whole network
# closed - totally disables IP services except via lo0 interface
# workstation - will try to protect just this machine using stateful
# firewalling. See below for rc.conf variables used
# UNKNOWN - disables the loading of firewall rules.
# filename - will load the rules in the given filename (full path required)
#
# For ``client'' and ``simple'' the entries below should be customized
# appropriately.
############
#
# If you don't know enough about packet filtering, we suggest that you
# take time to read this book:
#
# Building Internet Firewalls, 2nd Edition
# Brent Chapman and Elizabeth Zwicky
#
# O'Reilly & Associates, Inc
# ISBN 1-56592-871-7
# http://www.ora.com/
# http://www.oreilly.com/catalog/fire2/
#
# For a more advanced treatment of Internet Security read:
#
# Firewalls and Internet Security: Repelling the Wily Hacker, 2nd Edition
# William R. Cheswick, Steven M. Bellowin, Aviel D. Rubin
#
# Addison-Wesley / Prentice Hall
# ISBN 0-201-63466-X
# http://www.pearsonhighered.com/
# http://www.pearsonhighered.com/educator/academic/product/0,3110,020163466X,00.html
#
setup_loopback() {
############
# Only in rare cases do you want to change these rules
#
${fwcmd} add 100 pass all from any to any via lo0
${fwcmd} add 200 deny all from any to 127.0.0.0/8
${fwcmd} add 300 deny ip from 127.0.0.0/8 to any
if [ $ipv6_available -eq 0 ]; then
${fwcmd} add 400 deny all from any to ::1
${fwcmd} add 500 deny all from ::1 to any
fi
}
setup_ipv6_mandatory() {
[ $ipv6_available -eq 0 ] || return 0
############
# Only in rare cases do you want to change these rules
#
# ND
#
# DAD
${fwcmd} add pass ipv6-icmp from :: to ff02::/16
# RS, RA, NS, NA, redirect...
${fwcmd} add pass ipv6-icmp from fe80::/10 to fe80::/10
${fwcmd} add pass ipv6-icmp from fe80::/10 to ff02::/16
# Allow ICMPv6 destination unreachable
${fwcmd} add pass ipv6-icmp from any to any icmp6types 1
# Allow NS/NA/toobig (don't filter it out)
${fwcmd} add pass ipv6-icmp from any to any icmp6types 2,135,136
}
. /etc/rc.subr
. /etc/network.subr
if [ -n "${1}" ]; then
firewall_type="${1}"
fi
if [ -z "${firewall_rc_config_load}" ]; then
load_rc_config ipfw
else
for i in ${firewall_rc_config_load}; do
load_rc_config $i
done
fi
afexists inet6
ipv6_available=$?
############
# Set quiet mode if requested
#
case ${firewall_quiet} in
[Yy][Ee][Ss])
fwcmd="/sbin/ipfw -q"
;;
*)
fwcmd="/sbin/ipfw"
;;
esac
############
# Flush out the list before we begin.
#
${fwcmd} -f flush
setup_loopback
setup_ipv6_mandatory
############
# Network Address Translation. All packets are passed to natd(8)
# before they encounter your remaining rules. The firewall rules
# will then be run again on each packet after translation by natd
# starting at the rule number following the divert rule.
#
# For ``simple'' firewall type the divert rule should be put to a
# different place to not interfere with address-checking rules.
#
case ${firewall_type} in
[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt])
case ${natd_enable} in
[Yy][Ee][Ss])
if [ -n "${natd_interface}" ]; then
${fwcmd} add 50 divert natd ip4 from any to any via ${natd_interface}
fi
;;
esac
case ${firewall_nat_enable} in
[Yy][Ee][Ss])
if [ -n "${firewall_nat_interface}" ]; then
if echo "${firewall_nat_interface}" | \
grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then
firewall_nat_flags="ip ${firewall_nat_interface} ${firewall_nat_flags}"
else
firewall_nat_flags="if ${firewall_nat_interface} ${firewall_nat_flags}"
fi
${fwcmd} nat 123 config log ${firewall_nat_flags}
${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface}
fi
;;
esac
esac
############
# If you just configured ipfw in the kernel as a tool to solve network
# problems or you just want to disallow some particular kinds of traffic
# then you will want to change the default policy to open. You can also
# do this as your only action by setting the firewall_type to ``open''.
#
# ${fwcmd} add 65000 pass all from any to any
# Prototype setups.
#
case ${firewall_type} in
[Oo][Pp][Ee][Nn])
${fwcmd} add 65000 pass all from any to any
;;
[Cc][Ll][Ii][Ee][Nn][Tt])
############
# This is a prototype setup that will protect your system somewhat
# against people from outside your own network.
#
# Configuration:
# firewall_client_net: Network address of local IPv4 network.
# firewall_client_net_ipv6: Network address of local IPv6 network.
############
# set this to your local network
net="$firewall_client_net"
net6="$firewall_client_net_ipv6"
# Allow limited broadcast traffic from my own net.
${fwcmd} add pass all from ${net} to 255.255.255.255
# Allow any traffic to or from my own net.
${fwcmd} add pass all from me to ${net}
${fwcmd} add pass all from ${net} to me
if [ -n "$net6" ]; then
${fwcmd} add pass all from me to ${net6}
${fwcmd} add pass all from ${net6} to me
fi
if [ -n "$net6" ]; then
# Allow any link-local multicast traffic
${fwcmd} add pass all from fe80::/10 to ff02::/16
${fwcmd} add pass all from ${net6} to ff02::/16
# Allow DHCPv6
${fwcmd} add pass udp from fe80::/10 to me 546
fi
# Allow TCP through if setup succeeded
${fwcmd} add pass tcp from any to any established
# Allow IP fragments to pass through
${fwcmd} add pass all from any to any frag
# Allow setup of incoming email
${fwcmd} add pass tcp from any to me 25 setup
# Allow setup of outgoing TCP connections only
${fwcmd} add pass tcp from me to any setup
# Disallow setup of all other TCP connections
${fwcmd} add deny tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from me to any 53 keep-state
# Allow NTP queries out in the world
${fwcmd} add pass udp from me to any 123 keep-state
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
# config file.
;;
[Ss][Ii][Mm][Pp][Ll][Ee])
############
# This is a prototype setup for a simple firewall. Configure this
# machine as a DNS and NTP server, and point all the machines
# on the inside at this machine for those services.
#
# Configuration:
# firewall_simple_iif: Inside IPv4 network interface.
# firewall_simple_inet: Inside IPv4 network address.
# firewall_simple_oif: Outside IPv4 network interface.
# firewall_simple_onet: Outside IPv4 network address.
# firewall_simple_iif_ipv6: Inside IPv6 network interface.
# firewall_simple_inet_ipv6: Inside IPv6 network prefix.
# firewall_simple_oif_ipv6: Outside IPv6 network interface.
# firewall_simple_onet_ipv6: Outside IPv6 network prefix.
############
BAD_ADDR_TBL=13
# set these to your outside interface network
oif="$firewall_simple_oif"
onet="$firewall_simple_onet"
oif6="${firewall_simple_oif_ipv6:-$firewall_simple_oif}"
onet6="$firewall_simple_onet_ipv6"
# set these to your inside interface network
iif="$firewall_simple_iif"
inet="$firewall_simple_inet"
iif6="${firewall_simple_iif_ipv6:-$firewall_simple_iif}"
inet6="$firewall_simple_inet_ipv6"
# Stop spoofing
${fwcmd} add deny all from ${inet} to any in via ${oif}
${fwcmd} add deny all from ${onet} to any in via ${iif}
if [ -n "$inet6" ]; then
${fwcmd} add deny all from ${inet6} to any in via ${oif6}
if [ -n "$onet6" ]; then
${fwcmd} add deny all from ${onet6} to any in \
via ${iif6}
fi
fi
# Define stuff we should never send out or receive in.
# Stop RFC1918 nets on the outside interface
${fwcmd} table ${BAD_ADDR_TBL} flush
${fwcmd} table ${BAD_ADDR_TBL} add 10.0.0.0/8
${fwcmd} table ${BAD_ADDR_TBL} add 172.16.0.0/12
${fwcmd} table ${BAD_ADDR_TBL} add 192.168.0.0/16
# And stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
# DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
# on the outside interface
${fwcmd} table ${BAD_ADDR_TBL} add 0.0.0.0/8
${fwcmd} table ${BAD_ADDR_TBL} add 169.254.0.0/16
${fwcmd} table ${BAD_ADDR_TBL} add 192.0.2.0/24
${fwcmd} table ${BAD_ADDR_TBL} add 224.0.0.0/4
${fwcmd} table ${BAD_ADDR_TBL} add 240.0.0.0/4
${fwcmd} add deny all from any to "table($BAD_ADDR_TBL)" via ${oif}
# Network Address Translation. This rule is placed here deliberately
# so that it does not interfere with the surrounding address-checking
# rules. If for example one of your internal LAN machines had its IP
# address set to 192.0.2.1 then an incoming packet for it after being
# translated by natd(8) would match the `deny' rule above. Similarly
# an outgoing packet originated from it before being translated would
# match the `deny' rule below.
case ${natd_enable} in
[Yy][Ee][Ss])
if [ -n "${natd_interface}" ]; then
${fwcmd} add divert natd ip4 from any to any via ${natd_interface}
fi
;;
esac
${fwcmd} add deny all from "table($BAD_ADDR_TBL)" to any via ${oif}
if [ -n "$inet6" ]; then
# Stop unique local unicast address on the outside interface
${fwcmd} add deny all from fc00::/7 to any via ${oif6}
${fwcmd} add deny all from any to fc00::/7 via ${oif6}
# Stop site-local on the outside interface
${fwcmd} add deny all from fec0::/10 to any via ${oif6}
${fwcmd} add deny all from any to fec0::/10 via ${oif6}
# Disallow "internal" addresses to appear on the wire.
${fwcmd} add deny all from ::ffff:0.0.0.0/96 to any \
via ${oif6}
${fwcmd} add deny all from any to ::ffff:0.0.0.0/96 \
via ${oif6}
# Disallow packets to malicious IPv4 compatible prefix.
${fwcmd} add deny all from ::224.0.0.0/100 to any via ${oif6}
${fwcmd} add deny all from any to ::224.0.0.0/100 via ${oif6}
${fwcmd} add deny all from ::127.0.0.0/104 to any via ${oif6}
${fwcmd} add deny all from any to ::127.0.0.0/104 via ${oif6}
${fwcmd} add deny all from ::0.0.0.0/104 to any via ${oif6}
${fwcmd} add deny all from any to ::0.0.0.0/104 via ${oif6}
${fwcmd} add deny all from ::255.0.0.0/104 to any via ${oif6}
${fwcmd} add deny all from any to ::255.0.0.0/104 via ${oif6}
${fwcmd} add deny all from ::0.0.0.0/96 to any via ${oif6}
${fwcmd} add deny all from any to ::0.0.0.0/96 via ${oif6}
# Disallow packets to malicious 6to4 prefix.
${fwcmd} add deny all from 2002:e000::/20 to any via ${oif6}
${fwcmd} add deny all from any to 2002:e000::/20 via ${oif6}
${fwcmd} add deny all from 2002:7f00::/24 to any via ${oif6}
${fwcmd} add deny all from any to 2002:7f00::/24 via ${oif6}
${fwcmd} add deny all from 2002:0000::/24 to any via ${oif6}
${fwcmd} add deny all from any to 2002:0000::/24 via ${oif6}
${fwcmd} add deny all from 2002:ff00::/24 to any via ${oif6}
${fwcmd} add deny all from any to 2002:ff00::/24 via ${oif6}
${fwcmd} add deny all from 2002:0a00::/24 to any via ${oif6}
${fwcmd} add deny all from any to 2002:0a00::/24 via ${oif6}
${fwcmd} add deny all from 2002:ac10::/28 to any via ${oif6}
${fwcmd} add deny all from any to 2002:ac10::/28 via ${oif6}
${fwcmd} add deny all from 2002:c0a8::/32 to any via ${oif6}
${fwcmd} add deny all from any to 2002:c0a8::/32 via ${oif6}
${fwcmd} add deny all from ff05::/16 to any via ${oif6}
${fwcmd} add deny all from any to ff05::/16 via ${oif6}
fi
# Allow TCP through if setup succeeded
${fwcmd} add pass tcp from any to any established
# Allow IP fragments to pass through
${fwcmd} add pass all from any to any frag
# Allow setup of incoming email
${fwcmd} add pass tcp from any to me 25 setup
# Allow access to our DNS
${fwcmd} add pass tcp from any to me 53 setup
${fwcmd} add pass udp from any to me 53
${fwcmd} add pass udp from me 53 to any
# Allow access to our WWW
${fwcmd} add pass tcp from any to me 80 setup
# Reject&Log all setup of incoming connections from the outside
${fwcmd} add deny log ip4 from any to any in via ${oif} setup proto tcp
if [ -n "$inet6" ]; then
${fwcmd} add deny log ip6 from any to any in via ${oif6} \
setup proto tcp
fi
# Allow setup of any other TCP connection
${fwcmd} add pass tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from me to any 53 keep-state
# Allow NTP queries out in the world
${fwcmd} add pass udp from me to any 123 keep-state
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
# config file.
;;
[Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn])
# Configuration:
# firewall_myservices: List of ports/protocols on which this
# host offers services.
# firewall_allowservices: List of IPv4 and/or IPv6 addresses
# that have access to
# $firewall_myservices.
# firewall_trusted: List of IPv4 and/or IPv6 addresses
# that have full access to this host.
# Be very careful when setting this.
# This option can seriously degrade
# the level of protection provided by
# the firewall.
# firewall_logdeny: Boolean (YES/NO) specifying if the
# default denied packets should be
# logged (in /var/log/security).
# firewall_nologports: List of TCP/UDP ports for which
# denied incoming packets are not
# logged.
# Allow packets for which a state has been built.
${fwcmd} add check-state
# For services permitted below.
${fwcmd} add pass tcp from me to any established
# Allow any connection out, adding state for each.
${fwcmd} add pass tcp from me to any setup keep-state
${fwcmd} add pass udp from me to any keep-state
${fwcmd} add pass icmp from me to any keep-state
if [ $ipv6_available -eq 0 ]; then
${fwcmd} add pass ipv6-icmp from me to any keep-state
fi
# Allow DHCP.
${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out
${fwcmd} add pass udp from any 67 to me 68 in
${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in
if [ $ipv6_available -eq 0 ]; then
${fwcmd} add pass udp from fe80::/10 to me 546 in
fi
# Some servers will ping the IP while trying to decide if it's
# still in use.
${fwcmd} add pass icmp from any to any icmptype 8
if [ $ipv6_available -eq 0 ]; then
${fwcmd} add pass ipv6-icmp from any to any icmp6type 128,129
fi
# Allow "mandatory" ICMP in.
${fwcmd} add pass icmp from any to any icmptype 3,4,11
if [ $ipv6_available -eq 0 ]; then
${fwcmd} add pass ipv6-icmp from any to any icmp6type 3
fi
# Add permits for this workstations published services below
# Only IPs and nets in firewall_allowservices is allowed in.
# If you really wish to let anyone use services on your
# workstation, then set "firewall_allowservices='any'" in /etc/rc.conf
#
# Note: We don't use keep-state as that would allow DoS of
# our statetable.
# You can add 'keep-state' to the lines for slightly
# better performance if you fell that DoS of your
# workstation won't be a problem.
#
for i in ${firewall_allowservices} ; do
for j in ${firewall_myservices} ; do
case $j in
[0-9A-Za-z]*/[Pp][Rr][Oo][Tt][Oo])
${fwcmd} add pass ${j%/[Pp][Rr][Oo][Tt][Oo]} from $i to me
;;
[0-9A-Za-z]*/[Tt][Cc][Pp])
${fwcmd} add pass tcp from $i to me ${j%/[Tt][Cc][Pp]}
;;
[0-9A-Za-z]*/[Uu][Dd][Pp])
${fwcmd} add pass udp from $i to me ${j%/[Uu][Dd][Pp]}
;;
*[0-9A-Za-z])
echo "Consider using ${j}/tcp in firewall_myservices." \
> /dev/stderr
${fwcmd} add pass tcp from $i to me $j
;;
*)
echo "Invalid port in firewall_myservices: $j" > /dev/stderr
;;
esac
done
done
# Allow all connections from trusted IPs.
# Playing with the content of firewall_trusted could seriously
# degrade the level of protection provided by the firewall.
for i in ${firewall_trusted} ; do
${fwcmd} add pass ip from $i to me
done
${fwcmd} add 65000 count ip from any to any
# Drop packets to ports where we don't want logging
for i in ${firewall_nologports} ; do
${fwcmd} add deny { tcp or udp } from any to any $i in
done
# Broadcasts and multicasts
${fwcmd} add deny ip from any to 255.255.255.255
${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX
# Noise from routers
${fwcmd} add deny udp from any to any 520 in
# Noise from webbrowsing.
# The stateful filter is a bit aggressive, and will cause some
# connection teardowns to be logged.
${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in
# Deny and (if wanted) log the rest unconditionally.
log=""
if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then
log="log logamount 500" # The default of 100 is too low.
sysctl net.inet.ip.fw.verbose=1 >/dev/null
fi
${fwcmd} add deny $log ip from any to any
;;
[Cc][Ll][Oo][Ss][Ee][Dd])
${fwcmd} add 65000 deny ip from any to any
;;
[Uu][Nn][Kk][Nn][Oo][Ww][Nn])
;;
*)
if [ -r "${firewall_type}" ]; then
${fwcmd} ${firewall_flags} ${firewall_type}
fi
;;
esac