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Diffstat (limited to 'libexec/rc/rc.firewall')
| -rw-r--r-- | libexec/rc/rc.firewall | 553 |
1 files changed, 553 insertions, 0 deletions
diff --git a/libexec/rc/rc.firewall b/libexec/rc/rc.firewall new file mode 100644 index 000000000000..e4fc8cc3db78 --- /dev/null +++ b/libexec/rc/rc.firewall @@ -0,0 +1,553 @@ +#!/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. +# +# + +# +# 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 + # 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 |