rc.firewall revision 181761
1#!/bin/sh - 2# Copyright (c) 1996 Poul-Henning Kamp 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms, with or without 6# modification, are permitted provided that the following conditions 7# are met: 8# 1. Redistributions of source code must retain the above copyright 9# notice, this list of conditions and the following disclaimer. 10# 2. Redistributions in binary form must reproduce the above copyright 11# notice, this list of conditions and the following disclaimer in the 12# documentation and/or other materials provided with the distribution. 13# 14# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24# SUCH DAMAGE. 25# 26# $FreeBSD: head/etc/rc.firewall 181761 2008-08-15 19:14:25Z jhb $ 27# 28 29# 30# Setup system for ipfw(4) firewall service. 31# 32 33# Suck in the configuration variables. 34if [ -z "${source_rc_confs_defined}" ]; then 35 if [ -r /etc/defaults/rc.conf ]; then 36 . /etc/defaults/rc.conf 37 source_rc_confs 38 elif [ -r /etc/rc.conf ]; then 39 . /etc/rc.conf 40 fi 41fi 42 43############ 44# Define the firewall type in /etc/rc.conf. Valid values are: 45# open - will allow anyone in 46# client - will try to protect just this machine 47# simple - will try to protect a whole network 48# closed - totally disables IP services except via lo0 interface 49# workstation - will try to protect just this machine using statefull 50# firewalling. See below for rc.conf variables used 51# UNKNOWN - disables the loading of firewall rules. 52# filename - will load the rules in the given filename (full path required) 53# 54# For ``client'' and ``simple'' the entries below should be customized 55# appropriately. 56 57############ 58# 59# If you don't know enough about packet filtering, we suggest that you 60# take time to read this book: 61# 62# Building Internet Firewalls, 2nd Edition 63# Brent Chapman and Elizabeth Zwicky 64# 65# O'Reilly & Associates, Inc 66# ISBN 1-56592-871-7 67# http://www.ora.com/ 68# http://www.oreilly.com/catalog/fire2/ 69# 70# For a more advanced treatment of Internet Security read: 71# 72# Firewalls and Internet Security: Repelling the Wily Hacker, 2nd Edition 73# William R. Cheswick, Steven M. Bellowin, Aviel D. Rubin 74# 75# Addison-Wesley / Prentice Hall 76# ISBN 0-201-63466-X 77# http://www.pearsonhighered.com/ 78# http://www.pearsonhighered.com/educator/academic/product/0,3110,020163466X,00.html 79# 80 81setup_loopback () { 82 ############ 83 # Only in rare cases do you want to change these rules 84 # 85 ${fwcmd} add 100 pass all from any to any via lo0 86 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 87 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 88} 89 90if [ -n "${1}" ]; then 91 firewall_type="${1}" 92fi 93 94############ 95# Set quiet mode if requested 96# 97case ${firewall_quiet} in 98[Yy][Ee][Ss]) 99 fwcmd="/sbin/ipfw -q" 100 ;; 101*) 102 fwcmd="/sbin/ipfw" 103 ;; 104esac 105 106############ 107# Flush out the list before we begin. 108# 109${fwcmd} -f flush 110 111setup_loopback 112 113############ 114# Network Address Translation. All packets are passed to natd(8) 115# before they encounter your remaining rules. The firewall rules 116# will then be run again on each packet after translation by natd 117# starting at the rule number following the divert rule. 118# 119# For ``simple'' firewall type the divert rule should be put to a 120# different place to not interfere with address-checking rules. 121# 122case ${firewall_type} in 123[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 124 case ${natd_enable} in 125 [Yy][Ee][Ss]) 126 if [ -n "${natd_interface}" ]; then 127 ${fwcmd} add 50 divert natd ip4 from any to any via ${natd_interface} 128 fi 129 ;; 130 esac 131 case ${firewall_nat_enable} in 132 [Yy][Ee][Ss]) 133 if [ -n "${firewall_nat_interface}" ]; then 134 if echo "${firewall_nat_interface}" | \ 135 grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then 136 firewall_nat_flags="ip ${firewall_nat_interface} ${firewall_nat_flags}" 137 else 138 firewall_nat_flags="if ${firewall_nat_interface} ${firewall_nat_flags}" 139 fi 140 ${fwcmd} nat 123 config log ${firewall_nat_flags} 141 ${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface} 142 fi 143 ;; 144 esac 145esac 146 147############ 148# If you just configured ipfw in the kernel as a tool to solve network 149# problems or you just want to disallow some particular kinds of traffic 150# then you will want to change the default policy to open. You can also 151# do this as your only action by setting the firewall_type to ``open''. 152# 153# ${fwcmd} add 65000 pass all from any to any 154 155 156# Prototype setups. 157# 158case ${firewall_type} in 159[Oo][Pp][Ee][Nn]) 160 ${fwcmd} add 65000 pass all from any to any 161 ;; 162 163[Cc][Ll][Ii][Ee][Nn][Tt]) 164 ############ 165 # This is a prototype setup that will protect your system somewhat 166 # against people from outside your own network. 167 ############ 168 169 # set these to your network 170 net="192.0.2.0/24" 171 172 # Allow limited broadcast traffic from my own net. 173 ${fwcmd} add pass all from ${net} to 255.255.255.255 174 175 # Allow any traffic to or from my own net. 176 ${fwcmd} add pass all from me to ${net} 177 ${fwcmd} add pass all from ${net} to me 178 179 # Allow TCP through if setup succeeded 180 ${fwcmd} add pass tcp from any to any established 181 182 # Allow IP fragments to pass through 183 ${fwcmd} add pass all from any to any frag 184 185 # Allow setup of incoming email 186 ${fwcmd} add pass tcp from any to me 25 setup 187 188 # Allow setup of outgoing TCP connections only 189 ${fwcmd} add pass tcp from me to any setup 190 191 # Disallow setup of all other TCP connections 192 ${fwcmd} add deny tcp from any to any setup 193 194 # Allow DNS queries out in the world 195 ${fwcmd} add pass udp from me to any 53 keep-state 196 197 # Allow NTP queries out in the world 198 ${fwcmd} add pass udp from me to any 123 keep-state 199 200 # Everything else is denied by default, unless the 201 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 202 # config file. 203 ;; 204 205[Ss][Ii][Mm][Pp][Ll][Ee]) 206 ############ 207 # This is a prototype setup for a simple firewall. Configure this 208 # machine as a DNS and NTP server, and point all the machines 209 # on the inside at this machine for those services. 210 ############ 211 212 # set these to your outside interface network 213 oif="ed0" 214 onet="192.0.2.0/28" 215 216 # set these to your inside interface network 217 iif="ed1" 218 inet="192.0.2.16/28" 219 220 # Stop spoofing 221 ${fwcmd} add deny all from ${inet} to any in via ${oif} 222 ${fwcmd} add deny all from ${onet} to any in via ${iif} 223 224 # Stop RFC1918 nets on the outside interface 225 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 226 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 227 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 228 229 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 230 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 231 # on the outside interface 232 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 233 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 234 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 235 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 236 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 237 238 # Network Address Translation. This rule is placed here deliberately 239 # so that it does not interfere with the surrounding address-checking 240 # rules. If for example one of your internal LAN machines had its IP 241 # address set to 192.0.2.1 then an incoming packet for it after being 242 # translated by natd(8) would match the `deny' rule above. Similarly 243 # an outgoing packet originated from it before being translated would 244 # match the `deny' rule below. 245 case ${natd_enable} in 246 [Yy][Ee][Ss]) 247 if [ -n "${natd_interface}" ]; then 248 ${fwcmd} add divert natd all from any to any via ${natd_interface} 249 fi 250 ;; 251 esac 252 253 # Stop RFC1918 nets on the outside interface 254 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 255 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 256 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 257 258 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 259 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 260 # on the outside interface 261 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 262 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 263 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 264 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 265 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 266 267 # Allow TCP through if setup succeeded 268 ${fwcmd} add pass tcp from any to any established 269 270 # Allow IP fragments to pass through 271 ${fwcmd} add pass all from any to any frag 272 273 # Allow setup of incoming email 274 ${fwcmd} add pass tcp from any to me 25 setup 275 276 # Allow access to our DNS 277 ${fwcmd} add pass tcp from any to me 53 setup 278 ${fwcmd} add pass udp from any to me 53 279 ${fwcmd} add pass udp from me 53 to any 280 281 # Allow access to our WWW 282 ${fwcmd} add pass tcp from any to me 80 setup 283 284 # Reject&Log all setup of incoming connections from the outside 285 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 286 287 # Allow setup of any other TCP connection 288 ${fwcmd} add pass tcp from any to any setup 289 290 # Allow DNS queries out in the world 291 ${fwcmd} add pass udp from me to any 53 keep-state 292 293 # Allow NTP queries out in the world 294 ${fwcmd} add pass udp from me to any 123 keep-state 295 296 # Everything else is denied by default, unless the 297 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 298 # config file. 299 ;; 300 301[Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn]) 302 # Configuration: 303 # firewall_myservices: List of TCP ports on which this host 304 # offers services. 305 # firewall_allowservices: List of IPs which has access to 306 # $firewall_myservices. 307 # firewall_trusted: List of IPs which has full access 308 # to this host. Be very carefull 309 # when setting this. This option can 310 # seriously degrade the level of 311 # protection provided by the firewall. 312 # firewall_logdeny: Boolean (YES/NO) specifying if the 313 # default denied packets should be 314 # logged (in /var/log/security). 315 # firewall_nologports: List of TCP/UDP ports for which 316 # denied incomming packets are not 317 # logged. 318 319 # Allow packets for which a state has been built. 320 ${fwcmd} add check-state 321 322 # For services permitted below. 323 ${fwcmd} add pass tcp from me to any established 324 325 # Allow any connection out, adding state for each. 326 ${fwcmd} add pass tcp from me to any setup keep-state 327 ${fwcmd} add pass udp from me to any keep-state 328 ${fwcmd} add pass icmp from me to any keep-state 329 330 # Allow DHCP. 331 ${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out 332 ${fwcmd} add pass udp from any 67 to me 68 in 333 ${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in 334 # Some servers will ping the IP while trying to decide if it's 335 # still in use. 336 ${fwcmd} add pass icmp from any to any icmptype 8 337 338 # Allow "mandatory" ICMP in. 339 ${fwcmd} add pass icmp from any to any icmptype 3,4,11 340 341 # Add permits for this workstations published services below 342 # Only IPs and nets in firewall_allowservices is allowed in. 343 # If you really wish to let anyone use services on your 344 # workstation, then set "firewall_allowservices='any'" in /etc/rc.conf 345 # 346 # Note: We don't use keep-state as that would allow DoS of 347 # our statetable. 348 # You can add 'keep-state' to the lines for slightly 349 # better performance if you fell that DoS of your 350 # workstation won't be a problem. 351 # 352 for i in ${firewall_allowservices} ; do 353 for j in ${firewall_myservices} ; do 354 ${fwcmd} add pass tcp from $i to me $j 355 done 356 done 357 358 # Allow all connections from trusted IPs. 359 # Playing with the content of firewall_trusted could seriously 360 # degrade the level of protection provided by the firewall. 361 for i in ${firewall_trusted} ; do 362 ${fwcmd} add pass ip from $i to me 363 done 364 365 ${fwcmd} add 65000 count ip from any to any 366 367 # Drop packets to ports where we don't want logging 368 for i in ${firewall_nologports} ; do 369 ${fwcmd} add deny { tcp or udp } from any to any $i in 370 done 371 372 # Broadcasts and muticasts 373 ${fwcmd} add deny ip from any to 255.255.255.255 374 ${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX 375 376 # Noise from routers 377 ${fwcmd} add deny udp from any to any 520 in 378 379 # Noise from webbrowsing. 380 # The statefull filter is a bit agressive, and will cause some 381 # connection teardowns to be logged. 382 ${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in 383 384 # Deny and (if wanted) log the rest unconditionally. 385 log="" 386 if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then 387 log="log logamount 500" # The default of 100 is too low. 388 sysctl net.inet.ip.fw.verbose=1 >/dev/null 389 fi 390 ${fwcmd} add deny $log ip from any to any 391 ;; 392 393[Cc][Ll][Oo][Ss][Ee][Dd]) 394 ${fwcmd} add 65000 deny ip from any to any 395 ;; 396[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 397 ;; 398*) 399 if [ -r "${firewall_type}" ]; then 400 ${fwcmd} ${firewall_flags} ${firewall_type} 401 fi 402 ;; 403esac 404