rc.firewall revision 165648
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 165648 2006-12-29 21:59:17Z piso $ 27# 28 29# 30# Setup system for 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 & Internet Security 73# Repelling the wily hacker 74# William R. Cheswick, Steven M. Bellowin 75# 76# Addison-Wesley 77# ISBN 0-201-63357-4 78# http://www.awl.com/ 79# http://www.awlonline.com/product/0%2C2627%2C0201633574%2C00.html 80# 81 82setup_loopback () { 83 ############ 84 # Only in rare cases do you want to change these rules 85 # 86 ${fwcmd} add 100 pass all from any to any via lo0 87 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 88 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 89} 90 91if [ -n "${1}" ]; then 92 firewall_type="${1}" 93fi 94 95############ 96# Set quiet mode if requested 97# 98case ${firewall_quiet} in 99[Yy][Ee][Ss]) 100 fwcmd="/sbin/ipfw -q" 101 ;; 102*) 103 fwcmd="/sbin/ipfw" 104 ;; 105esac 106 107############ 108# Flush out the list before we begin. 109# 110${fwcmd} -f flush 111 112setup_loopback 113 114############ 115# Network Address Translation. All packets are passed to natd(8) 116# before they encounter your remaining rules. The firewall rules 117# will then be run again on each packet after translation by natd 118# starting at the rule number following the divert rule. 119# 120# For ``simple'' firewall type the divert rule should be put to a 121# different place to not interfere with address-checking rules. 122# 123case ${firewall_type} in 124[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 125 case ${natd_enable} in 126 [Yy][Ee][Ss]) 127 if [ -n "${natd_interface}" ]; then 128 ${fwcmd} add 50 divert natd ip4 from any to any via ${natd_interface} 129 fi 130 ;; 131 esac 132 case ${firewall_nat_enable} in 133 [Yy][Ee][Ss]) 134 if [ -n "${firewall_nat_interface}" ]; then 135 ${fwcmd} nat 123 config if ${firewall_nat_interface} log 136 ${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface} 137 fi 138 ;; 139 esac 140esac 141 142############ 143# If you just configured ipfw in the kernel as a tool to solve network 144# problems or you just want to disallow some particular kinds of traffic 145# then you will want to change the default policy to open. You can also 146# do this as your only action by setting the firewall_type to ``open''. 147# 148# ${fwcmd} add 65000 pass all from any to any 149 150 151# Prototype setups. 152# 153case ${firewall_type} in 154[Oo][Pp][Ee][Nn]) 155 ${fwcmd} add 65000 pass all from any to any 156 ;; 157 158[Cc][Ll][Ii][Ee][Nn][Tt]) 159 ############ 160 # This is a prototype setup that will protect your system somewhat 161 # against people from outside your own network. 162 ############ 163 164 # set these to your network and netmask and ip 165 net="192.0.2.0" 166 mask="255.255.255.0" 167 ip="192.0.2.1" 168 169 # Allow any traffic to or from my own net. 170 ${fwcmd} add pass all from ${ip} to ${net}:${mask} 171 ${fwcmd} add pass all from ${net}:${mask} to ${ip} 172 173 # Allow TCP through if setup succeeded 174 ${fwcmd} add pass tcp from any to any established 175 176 # Allow IP fragments to pass through 177 ${fwcmd} add pass all from any to any frag 178 179 # Allow setup of incoming email 180 ${fwcmd} add pass tcp from any to me 25 setup 181 182 # Allow setup of outgoing TCP connections only 183 ${fwcmd} add pass tcp from me to any setup 184 185 # Disallow setup of all other TCP connections 186 ${fwcmd} add deny tcp from any to any setup 187 188 # Allow DNS queries out in the world 189 ${fwcmd} add pass udp from me to any 53 keep-state 190 191 # Allow NTP queries out in the world 192 ${fwcmd} add pass udp from me to any 123 keep-state 193 194 # Everything else is denied by default, unless the 195 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 196 # config file. 197 ;; 198 199[Ss][Ii][Mm][Pp][Ll][Ee]) 200 ############ 201 # This is a prototype setup for a simple firewall. Configure this 202 # machine as a DNS and NTP server, and point all the machines 203 # on the inside at this machine for those services. 204 ############ 205 206 # set these to your outside interface network and netmask and ip 207 oif="ed0" 208 onet="192.0.2.0" 209 omask="255.255.255.240" 210 oip="192.0.2.1" 211 212 # set these to your inside interface network and netmask and ip 213 iif="ed1" 214 inet="192.0.2.16" 215 imask="255.255.255.240" 216 iip="192.0.2.17" 217 218 # Stop spoofing 219 ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif} 220 ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif} 221 222 # Stop RFC1918 nets on the outside interface 223 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 224 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 225 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 226 227 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 228 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 229 # on the outside interface 230 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 231 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 232 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 233 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 234 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 235 236 # Network Address Translation. This rule is placed here deliberately 237 # so that it does not interfere with the surrounding address-checking 238 # rules. If for example one of your internal LAN machines had its IP 239 # address set to 192.0.2.1 then an incoming packet for it after being 240 # translated by natd(8) would match the `deny' rule above. Similarly 241 # an outgoing packet originated from it before being translated would 242 # match the `deny' rule below. 243 case ${natd_enable} in 244 [Yy][Ee][Ss]) 245 if [ -n "${natd_interface}" ]; then 246 ${fwcmd} add divert natd all from any to any via ${natd_interface} 247 fi 248 ;; 249 esac 250 251 # Stop RFC1918 nets on the outside interface 252 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 253 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 254 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 255 256 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 257 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 258 # on the outside interface 259 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 260 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 261 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 262 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 263 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 264 265 # Allow TCP through if setup succeeded 266 ${fwcmd} add pass tcp from any to any established 267 268 # Allow IP fragments to pass through 269 ${fwcmd} add pass all from any to any frag 270 271 # Allow setup of incoming email 272 ${fwcmd} add pass tcp from any to ${oip} 25 setup 273 274 # Allow access to our DNS 275 ${fwcmd} add pass tcp from any to ${oip} 53 setup 276 ${fwcmd} add pass udp from any to ${oip} 53 277 ${fwcmd} add pass udp from ${oip} 53 to any 278 279 # Allow access to our WWW 280 ${fwcmd} add pass tcp from any to ${oip} 80 setup 281 282 # Reject&Log all setup of incoming connections from the outside 283 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 284 285 # Allow setup of any other TCP connection 286 ${fwcmd} add pass tcp from any to any setup 287 288 # Allow DNS queries out in the world 289 ${fwcmd} add pass udp from ${oip} to any 53 keep-state 290 291 # Allow NTP queries out in the world 292 ${fwcmd} add pass udp from ${oip} to any 123 keep-state 293 294 # Everything else is denied by default, unless the 295 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 296 # config file. 297 ;; 298 299[Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn]) 300 # Configuration: 301 # firewall_myservices: List of TCP ports on which this host 302 # offers services. 303 # firewall_allowservices: List of IPs which has access to 304 # $firewall_myservices. 305 # firewall_trusted: List of IPs which has full access 306 # to this host. Be very carefull 307 # when setting this. This option can 308 # seriously degrade the level of 309 # protection provided by the firewall. 310 # firewall_logdeny: Boolean (YES/NO) specifying if the 311 # default denied packets should be 312 # logged (in /var/log/security). 313 # firewall_nologports: List of TCP/UDP ports for which 314 # denied incomming packets are not 315 # logged. 316 317 # Allow packets for which a state has been built. 318 ${fwcmd} add check-state 319 320 # For services permitted below. 321 ${fwcmd} add pass tcp from me to any established 322 323 # Allow any connection out, adding state for each. 324 ${fwcmd} add pass tcp from me to any setup keep-state 325 ${fwcmd} add pass udp from me to any keep-state 326 ${fwcmd} add pass icmp from me to any keep-state 327 328 # Allow DHCP. 329 ${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out 330 ${fwcmd} add pass udp from any 67 to me 68 in 331 ${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in 332 # Some servers will ping the IP while trying to decide if it's 333 # still in use. 334 ${fwcmd} add pass icmp from any to any icmptype 8 335 336 # Allow "mandatory" ICMP in. 337 ${fwcmd} add pass icmp from any to any icmptype 3,4,11 338 339 # Add permits for this workstations published services below 340 # Only IPs and nets in firewall_allowservices is allowed in. 341 # If you really wish to let anyone use services on your 342 # workstation, then set "firewall_allowservices='any'" in /etc/rc.conf 343 # 344 # Note: We don't use keep-state as that would allow DoS of 345 # our statetable. 346 # You can add 'keep-state' to the lines for slightly 347 # better performance if you fell that DoS of your 348 # workstation won't be a problem. 349 # 350 for i in ${firewall_allowservices} ; do 351 for j in ${firewall_myservices} ; do 352 ${fwcmd} add pass tcp from $i to me $j 353 done 354 done 355 356 # Allow all connections from trusted IPs. 357 # Playing with the content of firewall_trusted could seriously 358 # degrade the level of protection provided by the firewall. 359 for i in ${firewall_trusted} ; do 360 ${fwcmd} add pass ip from $i to me 361 done 362 363 ${fwcmd} add 65000 count ip from any to any 364 365 # Drop packets to ports where we don't want logging 366 for i in ${firewall_nologports} ; do 367 ${fwcmd} add deny { tcp or udp } from any to any $i in 368 done 369 370 # Broadcasts and muticasts 371 ${fwcmd} add deny ip from any to 255.255.255.255 372 ${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX 373 374 # Noise from routers 375 ${fwcmd} add deny udp from any to any 520 in 376 377 # Noise from webbrowsing. 378 # The statefull filter is a bit agressive, and will cause some 379 # connection teardowns to be logged. 380 ${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in 381 382 # Deny and (if wanted) log the rest unconditionally. 383 log="" 384 if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then 385 log="log logamount 500" # The default of 100 is too low. 386 sysctl net.inet.ip.fw.verbose=1 >/dev/null 387 fi 388 ${fwcmd} add deny $log ip from any to any 389 ;; 390 391[Cc][Ll][Oo][Ss][Ee][Dd]) 392 ${fwcmd} add 65000 deny ip from any to any 393 ;; 394[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 395 ;; 396*) 397 if [ -r "${firewall_type}" ]; then 398 ${fwcmd} ${firewall_flags} ${firewall_type} 399 fi 400 ;; 401esac 402