rc.firewall revision 181760
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 181760 2008-08-15 18:58:15Z 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 and netmask and ip 170 net="192.0.2.0" 171 mask="255.255.255.0" 172 173 # Allow limited broadcast traffic from my own net. 174 ${fwcmd} add pass all from ${net}:${mask} to 255.255.255.255 175 176 # Allow any traffic to or from my own net. 177 ${fwcmd} add pass all from me to ${net}:${mask} 178 ${fwcmd} add pass all from ${net}:${mask} to me 179 180 # Allow TCP through if setup succeeded 181 ${fwcmd} add pass tcp from any to any established 182 183 # Allow IP fragments to pass through 184 ${fwcmd} add pass all from any to any frag 185 186 # Allow setup of incoming email 187 ${fwcmd} add pass tcp from any to me 25 setup 188 189 # Allow setup of outgoing TCP connections only 190 ${fwcmd} add pass tcp from me to any setup 191 192 # Disallow setup of all other TCP connections 193 ${fwcmd} add deny tcp from any to any setup 194 195 # Allow DNS queries out in the world 196 ${fwcmd} add pass udp from me to any 53 keep-state 197 198 # Allow NTP queries out in the world 199 ${fwcmd} add pass udp from me to any 123 keep-state 200 201 # Everything else is denied by default, unless the 202 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 203 # config file. 204 ;; 205 206[Ss][Ii][Mm][Pp][Ll][Ee]) 207 ############ 208 # This is a prototype setup for a simple firewall. Configure this 209 # machine as a DNS and NTP server, and point all the machines 210 # on the inside at this machine for those services. 211 ############ 212 213 # set these to your outside interface network and netmask and ip 214 oif="ed0" 215 onet="192.0.2.0" 216 omask="255.255.255.240" 217 218 # set these to your inside interface network and netmask and ip 219 iif="ed1" 220 inet="192.0.2.16" 221 imask="255.255.255.240" 222 223 # Stop spoofing 224 ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif} 225 ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif} 226 227 # Stop RFC1918 nets on the outside interface 228 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 229 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 230 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 231 232 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 233 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 234 # on the outside interface 235 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 236 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 237 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 238 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 239 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 240 241 # Network Address Translation. This rule is placed here deliberately 242 # so that it does not interfere with the surrounding address-checking 243 # rules. If for example one of your internal LAN machines had its IP 244 # address set to 192.0.2.1 then an incoming packet for it after being 245 # translated by natd(8) would match the `deny' rule above. Similarly 246 # an outgoing packet originated from it before being translated would 247 # match the `deny' rule below. 248 case ${natd_enable} in 249 [Yy][Ee][Ss]) 250 if [ -n "${natd_interface}" ]; then 251 ${fwcmd} add divert natd all from any to any via ${natd_interface} 252 fi 253 ;; 254 esac 255 256 # Stop RFC1918 nets on the outside interface 257 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 258 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 259 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 260 261 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 262 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 263 # on the outside interface 264 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 265 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 266 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 267 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 268 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 269 270 # Allow TCP through if setup succeeded 271 ${fwcmd} add pass tcp from any to any established 272 273 # Allow IP fragments to pass through 274 ${fwcmd} add pass all from any to any frag 275 276 # Allow setup of incoming email 277 ${fwcmd} add pass tcp from any to me 25 setup 278 279 # Allow access to our DNS 280 ${fwcmd} add pass tcp from any to me 53 setup 281 ${fwcmd} add pass udp from any to me 53 282 ${fwcmd} add pass udp from me 53 to any 283 284 # Allow access to our WWW 285 ${fwcmd} add pass tcp from any to me 80 setup 286 287 # Reject&Log all setup of incoming connections from the outside 288 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 289 290 # Allow setup of any other TCP connection 291 ${fwcmd} add pass tcp from any to any setup 292 293 # Allow DNS queries out in the world 294 ${fwcmd} add pass udp from me to any 53 keep-state 295 296 # Allow NTP queries out in the world 297 ${fwcmd} add pass udp from me to any 123 keep-state 298 299 # Everything else is denied by default, unless the 300 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 301 # config file. 302 ;; 303 304[Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn]) 305 # Configuration: 306 # firewall_myservices: List of TCP ports on which this host 307 # offers services. 308 # firewall_allowservices: List of IPs which has access to 309 # $firewall_myservices. 310 # firewall_trusted: List of IPs which has full access 311 # to this host. Be very carefull 312 # when setting this. This option can 313 # seriously degrade the level of 314 # protection provided by the firewall. 315 # firewall_logdeny: Boolean (YES/NO) specifying if the 316 # default denied packets should be 317 # logged (in /var/log/security). 318 # firewall_nologports: List of TCP/UDP ports for which 319 # denied incomming packets are not 320 # logged. 321 322 # Allow packets for which a state has been built. 323 ${fwcmd} add check-state 324 325 # For services permitted below. 326 ${fwcmd} add pass tcp from me to any established 327 328 # Allow any connection out, adding state for each. 329 ${fwcmd} add pass tcp from me to any setup keep-state 330 ${fwcmd} add pass udp from me to any keep-state 331 ${fwcmd} add pass icmp from me to any keep-state 332 333 # Allow DHCP. 334 ${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out 335 ${fwcmd} add pass udp from any 67 to me 68 in 336 ${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in 337 # Some servers will ping the IP while trying to decide if it's 338 # still in use. 339 ${fwcmd} add pass icmp from any to any icmptype 8 340 341 # Allow "mandatory" ICMP in. 342 ${fwcmd} add pass icmp from any to any icmptype 3,4,11 343 344 # Add permits for this workstations published services below 345 # Only IPs and nets in firewall_allowservices is allowed in. 346 # If you really wish to let anyone use services on your 347 # workstation, then set "firewall_allowservices='any'" in /etc/rc.conf 348 # 349 # Note: We don't use keep-state as that would allow DoS of 350 # our statetable. 351 # You can add 'keep-state' to the lines for slightly 352 # better performance if you fell that DoS of your 353 # workstation won't be a problem. 354 # 355 for i in ${firewall_allowservices} ; do 356 for j in ${firewall_myservices} ; do 357 ${fwcmd} add pass tcp from $i to me $j 358 done 359 done 360 361 # Allow all connections from trusted IPs. 362 # Playing with the content of firewall_trusted could seriously 363 # degrade the level of protection provided by the firewall. 364 for i in ${firewall_trusted} ; do 365 ${fwcmd} add pass ip from $i to me 366 done 367 368 ${fwcmd} add 65000 count ip from any to any 369 370 # Drop packets to ports where we don't want logging 371 for i in ${firewall_nologports} ; do 372 ${fwcmd} add deny { tcp or udp } from any to any $i in 373 done 374 375 # Broadcasts and muticasts 376 ${fwcmd} add deny ip from any to 255.255.255.255 377 ${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX 378 379 # Noise from routers 380 ${fwcmd} add deny udp from any to any 520 in 381 382 # Noise from webbrowsing. 383 # The statefull filter is a bit agressive, and will cause some 384 # connection teardowns to be logged. 385 ${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in 386 387 # Deny and (if wanted) log the rest unconditionally. 388 log="" 389 if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then 390 log="log logamount 500" # The default of 100 is too low. 391 sysctl net.inet.ip.fw.verbose=1 >/dev/null 392 fi 393 ${fwcmd} add deny $log ip from any to any 394 ;; 395 396[Cc][Ll][Oo][Ss][Ee][Dd]) 397 ${fwcmd} add 65000 deny ip from any to any 398 ;; 399[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 400 ;; 401*) 402 if [ -r "${firewall_type}" ]; then 403 ${fwcmd} ${firewall_flags} ${firewall_type} 404 fi 405 ;; 406esac 407