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# $FreeBSD$ 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 stateful 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 if [ $ipv6_available -eq 0 ]; then 89 ${fwcmd} add 400 deny all from any to ::1 90 ${fwcmd} add 500 deny all from ::1 to any 91 fi 92} 93 94setup_ipv6_mandatory() { 95 [ $ipv6_available -eq 0 ] || return 0 96 97 ############ 98 # Only in rare cases do you want to change these rules 99 # 100 # ND 101 # 102 # DAD 103 ${fwcmd} add pass ipv6-icmp from :: to ff02::/16 104 # RS, RA, NS, NA, redirect... 105 ${fwcmd} add pass ipv6-icmp from fe80::/10 to fe80::/10 106 ${fwcmd} add pass ipv6-icmp from fe80::/10 to ff02::/16 107 108 # Allow ICMPv6 destination unreachable 109 ${fwcmd} add pass ipv6-icmp from any to any icmp6types 1 110 111 # Allow NS/NA/toobig (don't filter it out) 112 ${fwcmd} add pass ipv6-icmp from any to any icmp6types 2,135,136 113} 114 115. /etc/rc.subr 116. /etc/network.subr 117 118if [ -n "${1}" ]; then 119 firewall_type="${1}" 120fi 121if [ -z "${firewall_rc_config_load}" ]; then 122 load_rc_config ipfw 123else 124 for i in ${firewall_rc_config_load}; do 125 load_rc_config $i 126 done 127fi 128 129afexists inet6 130ipv6_available=$? 131 132############ 133# Set quiet mode if requested 134# 135case ${firewall_quiet} in 136[Yy][Ee][Ss]) 137 fwcmd="/sbin/ipfw -q" 138 ;; 139*) 140 fwcmd="/sbin/ipfw" 141 ;; 142esac 143 144############ 145# Flush out the list before we begin. 146# 147${fwcmd} -f flush 148 149setup_loopback 150setup_ipv6_mandatory 151 152############ 153# Network Address Translation. All packets are passed to natd(8) 154# before they encounter your remaining rules. The firewall rules 155# will then be run again on each packet after translation by natd 156# starting at the rule number following the divert rule. 157# 158# For ``simple'' firewall type the divert rule should be put to a 159# different place to not interfere with address-checking rules. 160# 161case ${firewall_type} in 162[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 163 case ${natd_enable} in 164 [Yy][Ee][Ss]) 165 if [ -n "${natd_interface}" ]; then 166 ${fwcmd} add 50 divert natd ip4 from any to any via ${natd_interface} 167 fi 168 ;; 169 esac 170 case ${firewall_nat_enable} in 171 [Yy][Ee][Ss]) 172 if [ -n "${firewall_nat_interface}" ]; then 173 if echo "${firewall_nat_interface}" | \ 174 grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then 175 firewall_nat_flags="ip ${firewall_nat_interface} ${firewall_nat_flags}" 176 else 177 firewall_nat_flags="if ${firewall_nat_interface} ${firewall_nat_flags}" 178 fi 179 ${fwcmd} nat 123 config log ${firewall_nat_flags} 180 ${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface} 181 fi 182 ;; 183 esac 184esac 185 186############ 187# If you just configured ipfw in the kernel as a tool to solve network 188# problems or you just want to disallow some particular kinds of traffic 189# then you will want to change the default policy to open. You can also 190# do this as your only action by setting the firewall_type to ``open''. 191# 192# ${fwcmd} add 65000 pass all from any to any 193 194 195# Prototype setups. 196# 197case ${firewall_type} in 198[Oo][Pp][Ee][Nn]) 199 ${fwcmd} add 65000 pass all from any to any 200 ;; 201 202[Cc][Ll][Ii][Ee][Nn][Tt]) 203 ############ 204 # This is a prototype setup that will protect your system somewhat 205 # against people from outside your own network. 206 # 207 # Configuration: 208 # firewall_client_net: Network address of local IPv4 network. 209 # firewall_client_net_ipv6: Network address of local IPv6 network. 210 ############ 211 212 # set this to your local network 213 net="$firewall_client_net" 214 net6="$firewall_client_net_ipv6" 215 216 # Allow limited broadcast traffic from my own net. 217 ${fwcmd} add pass all from ${net} to 255.255.255.255 218 219 # Allow any traffic to or from my own net. 220 ${fwcmd} add pass all from me to ${net} 221 ${fwcmd} add pass all from ${net} to me 222 if [ -n "$net6" ]; then 223 ${fwcmd} add pass all from me to ${net6} 224 ${fwcmd} add pass all from ${net6} to me 225 # Allow any link-local multicast traffic 226 ${fwcmd} add pass all from fe80::/10 to ff02::/16 227 ${fwcmd} add pass all from ${net6} to ff02::/16 228 # Allow DHCPv6 229 ${fwcmd} add pass udp from fe80::/10 to me 546 230 fi 231 232 # Allow TCP through if setup succeeded 233 ${fwcmd} add pass tcp from any to any established 234 235 # Allow IP fragments to pass through 236 ${fwcmd} add pass all from any to any frag 237 238 # Allow setup of incoming email 239 ${fwcmd} add pass tcp from any to me 25 setup 240 241 # Allow setup of outgoing TCP connections only 242 ${fwcmd} add pass tcp from me to any setup 243 244 # Disallow setup of all other TCP connections 245 ${fwcmd} add deny tcp from any to any setup 246 247 # Allow DNS queries out in the world 248 ${fwcmd} add pass udp from me to any 53 keep-state 249 250 # Allow NTP queries out in the world 251 ${fwcmd} add pass udp from me to any 123 keep-state 252 253 # Everything else is denied by default, unless the 254 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 255 # config file. 256 ;; 257 258[Ss][Ii][Mm][Pp][Ll][Ee]) 259 ############ 260 # This is a prototype setup for a simple firewall. Configure this 261 # machine as a DNS and NTP server, and point all the machines 262 # on the inside at this machine for those services. 263 # 264 # Configuration: 265 # firewall_simple_iif: Inside IPv4 network interface. 266 # firewall_simple_inet: Inside IPv4 network address. 267 # firewall_simple_oif: Outside IPv4 network interface. 268 # firewall_simple_onet: Outside IPv4 network address. 269 # firewall_simple_iif_ipv6: Inside IPv6 network interface. 270 # firewall_simple_inet_ipv6: Inside IPv6 network prefix. 271 # firewall_simple_oif_ipv6: Outside IPv6 network interface. 272 # firewall_simple_onet_ipv6: Outside IPv6 network prefix. 273 ############ 274 BAD_ADDR_TBL=13 275 276 # set these to your outside interface network 277 oif="$firewall_simple_oif" 278 onet="$firewall_simple_onet" 279 oif6="${firewall_simple_oif_ipv6:-$firewall_simple_oif}" 280 onet6="$firewall_simple_onet_ipv6" 281 282 # set these to your inside interface network 283 iif="$firewall_simple_iif" 284 inet="$firewall_simple_inet" 285 iif6="${firewall_simple_iif_ipv6:-$firewall_simple_iif}" 286 inet6="$firewall_simple_inet_ipv6" 287 288 # Stop spoofing 289 ${fwcmd} add deny all from ${inet} to any in via ${oif} 290 ${fwcmd} add deny all from ${onet} to any in via ${iif} 291 if [ -n "$inet6" ]; then 292 ${fwcmd} add deny all from ${inet6} to any in via ${oif6} 293 if [ -n "$onet6" ]; then 294 ${fwcmd} add deny all from ${onet6} to any in \ 295 via ${iif6} 296 fi 297 fi 298 299 # Define stuff we should never send out or receive in. 300 # Stop RFC1918 nets on the outside interface 301 ${fwcmd} table ${BAD_ADDR_TBL} flush 302 ${fwcmd} table ${BAD_ADDR_TBL} add 10.0.0.0/8 303 ${fwcmd} table ${BAD_ADDR_TBL} add 172.16.0.0/12 304 ${fwcmd} table ${BAD_ADDR_TBL} add 192.168.0.0/16 305 306 # And stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 307 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 308 # on the outside interface 309 ${fwcmd} table ${BAD_ADDR_TBL} add 0.0.0.0/8 310 ${fwcmd} table ${BAD_ADDR_TBL} add 169.254.0.0/16 311 ${fwcmd} table ${BAD_ADDR_TBL} add 192.0.2.0/24 312 ${fwcmd} table ${BAD_ADDR_TBL} add 224.0.0.0/4 313 ${fwcmd} table ${BAD_ADDR_TBL} add 240.0.0.0/4 314 315 ${fwcmd} add deny all from any to "table($BAD_ADDR_TBL)" via ${oif} 316 317 # Network Address Translation. This rule is placed here deliberately 318 # so that it does not interfere with the surrounding address-checking 319 # rules. If for example one of your internal LAN machines had its IP 320 # address set to 192.0.2.1 then an incoming packet for it after being 321 # translated by natd(8) would match the `deny' rule above. Similarly 322 # an outgoing packet originated from it before being translated would 323 # match the `deny' rule below. 324 case ${natd_enable} in 325 [Yy][Ee][Ss]) 326 if [ -n "${natd_interface}" ]; then 327 ${fwcmd} add divert natd ip4 from any to any via ${natd_interface} 328 fi 329 ;; 330 esac 331 332 ${fwcmd} add deny all from "table($BAD_ADDR_TBL)" to any via ${oif} 333 if [ -n "$inet6" ]; then 334 # Stop unique local unicast address on the outside interface 335 ${fwcmd} add deny all from fc00::/7 to any via ${oif6} 336 ${fwcmd} add deny all from any to fc00::/7 via ${oif6} 337 338 # Stop site-local on the outside interface 339 ${fwcmd} add deny all from fec0::/10 to any via ${oif6} 340 ${fwcmd} add deny all from any to fec0::/10 via ${oif6} 341 342 # Disallow "internal" addresses to appear on the wire. 343 ${fwcmd} add deny all from ::ffff:0.0.0.0/96 to any \ 344 via ${oif6} 345 ${fwcmd} add deny all from any to ::ffff:0.0.0.0/96 \ 346 via ${oif6} 347 348 # Disallow packets to malicious IPv4 compatible prefix. 349 ${fwcmd} add deny all from ::224.0.0.0/100 to any via ${oif6} 350 ${fwcmd} add deny all from any to ::224.0.0.0/100 via ${oif6} 351 ${fwcmd} add deny all from ::127.0.0.0/104 to any via ${oif6} 352 ${fwcmd} add deny all from any to ::127.0.0.0/104 via ${oif6} 353 ${fwcmd} add deny all from ::0.0.0.0/104 to any via ${oif6} 354 ${fwcmd} add deny all from any to ::0.0.0.0/104 via ${oif6} 355 ${fwcmd} add deny all from ::255.0.0.0/104 to any via ${oif6} 356 ${fwcmd} add deny all from any to ::255.0.0.0/104 via ${oif6} 357 358 ${fwcmd} add deny all from ::0.0.0.0/96 to any via ${oif6} 359 ${fwcmd} add deny all from any to ::0.0.0.0/96 via ${oif6} 360 361 # Disallow packets to malicious 6to4 prefix. 362 ${fwcmd} add deny all from 2002:e000::/20 to any via ${oif6} 363 ${fwcmd} add deny all from any to 2002:e000::/20 via ${oif6} 364 ${fwcmd} add deny all from 2002:7f00::/24 to any via ${oif6} 365 ${fwcmd} add deny all from any to 2002:7f00::/24 via ${oif6} 366 ${fwcmd} add deny all from 2002:0000::/24 to any via ${oif6} 367 ${fwcmd} add deny all from any to 2002:0000::/24 via ${oif6} 368 ${fwcmd} add deny all from 2002:ff00::/24 to any via ${oif6} 369 ${fwcmd} add deny all from any to 2002:ff00::/24 via ${oif6} 370 371 ${fwcmd} add deny all from 2002:0a00::/24 to any via ${oif6} 372 ${fwcmd} add deny all from any to 2002:0a00::/24 via ${oif6} 373 ${fwcmd} add deny all from 2002:ac10::/28 to any via ${oif6} 374 ${fwcmd} add deny all from any to 2002:ac10::/28 via ${oif6} 375 ${fwcmd} add deny all from 2002:c0a8::/32 to any via ${oif6} 376 ${fwcmd} add deny all from any to 2002:c0a8::/32 via ${oif6} 377 378 ${fwcmd} add deny all from ff05::/16 to any via ${oif6} 379 ${fwcmd} add deny all from any to ff05::/16 via ${oif6} 380 fi 381 382 # Allow TCP through if setup succeeded 383 ${fwcmd} add pass tcp from any to any established 384 385 # Allow IP fragments to pass through 386 ${fwcmd} add pass all from any to any frag 387 388 # Allow setup of incoming email 389 ${fwcmd} add pass tcp from any to me 25 setup 390 391 # Allow access to our DNS 392 ${fwcmd} add pass tcp from any to me 53 setup 393 ${fwcmd} add pass udp from any to me 53 394 ${fwcmd} add pass udp from me 53 to any 395 396 # Allow access to our WWW 397 ${fwcmd} add pass tcp from any to me 80 setup 398 399 # Reject&Log all setup of incoming connections from the outside 400 ${fwcmd} add deny log ip4 from any to any in via ${oif} setup proto tcp 401 if [ -n "$inet6" ]; then 402 ${fwcmd} add deny log ip6 from any to any in via ${oif6} \ 403 setup proto tcp 404 fi 405 406 # Allow setup of any other TCP connection 407 ${fwcmd} add pass tcp from any to any setup 408 409 # Allow DNS queries out in the world 410 ${fwcmd} add pass udp from me to any 53 keep-state 411 412 # Allow NTP queries out in the world 413 ${fwcmd} add pass udp from me to any 123 keep-state 414 415 # Everything else is denied by default, unless the 416 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 417 # config file. 418 ;; 419 420[Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn]) 421 # Configuration: 422 # firewall_myservices: List of ports/protocols on which this 423 # host offers services. 424 # firewall_allowservices: List of IPv4 and/or IPv6 addresses 425 # that have access to 426 # $firewall_myservices. 427 # firewall_trusted: List of IPv4 and/or IPv6 addresses 428 # that have full access to this host. 429 # Be very careful when setting this. 430 # This option can seriously degrade 431 # the level of protection provided by 432 # the firewall. 433 # firewall_logdeny: Boolean (YES/NO) specifying if the 434 # default denied packets should be 435 # logged (in /var/log/security). 436 # firewall_nologports: List of TCP/UDP ports for which 437 # denied incoming packets are not 438 # logged. 439 440 # Allow packets for which a state has been built. 441 ${fwcmd} add check-state 442 443 # For services permitted below. 444 ${fwcmd} add pass tcp from me to any established 445 446 # Allow any connection out, adding state for each. 447 ${fwcmd} add pass tcp from me to any setup keep-state 448 ${fwcmd} add pass udp from me to any keep-state 449 ${fwcmd} add pass icmp from me to any keep-state 450 if [ $ipv6_available -eq 0 ]; then 451 ${fwcmd} add pass ipv6-icmp from me to any keep-state 452 fi 453 454 # Allow DHCP. 455 ${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out 456 ${fwcmd} add pass udp from any 67 to me 68 in 457 ${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in 458 if [ $ipv6_available -eq 0 ]; then 459 ${fwcmd} add pass udp from fe80::/10 to me 546 in 460 fi 461 # Some servers will ping the IP while trying to decide if it's 462 # still in use. 463 ${fwcmd} add pass icmp from any to any icmptype 8 464 if [ $ipv6_available -eq 0 ]; then 465 ${fwcmd} add pass ipv6-icmp from any to any icmp6type 128,129 466 fi 467 468 # Allow "mandatory" ICMP in. 469 ${fwcmd} add pass icmp from any to any icmptype 3,4,11 470 if [ $ipv6_available -eq 0 ]; then 471 ${fwcmd} add pass ipv6-icmp from any to any icmp6type 3 472 fi 473 474 # Add permits for this workstations published services below 475 # Only IPs and nets in firewall_allowservices is allowed in. 476 # If you really wish to let anyone use services on your 477 # workstation, then set "firewall_allowservices='any'" in /etc/rc.conf 478 # 479 # Note: We don't use keep-state as that would allow DoS of 480 # our statetable. 481 # You can add 'keep-state' to the lines for slightly 482 # better performance if you fell that DoS of your 483 # workstation won't be a problem. 484 # 485 for i in ${firewall_allowservices} ; do 486 for j in ${firewall_myservices} ; do 487 case $j in 488 [0-9A-Za-z]*/[Pp][Rr][Oo][Tt][Oo]) 489 ${fwcmd} add pass ${j%/[Pp][Rr][Oo][Tt][Oo]} from $i to me 490 ;; 491 [0-9A-Za-z]*/[Tt][Cc][Pp]) 492 ${fwcmd} add pass tcp from $i to me ${j%/[Tt][Cc][Pp]} 493 ;; 494 [0-9A-Za-z]*/[Uu][Dd][Pp]) 495 ${fwcmd} add pass udp from $i to me ${j%/[Uu][Dd][Pp]} 496 ;; 497 *[0-9A-Za-z]) 498 echo "Consider using ${j}/tcp in firewall_myservices." \ 499 > /dev/stderr 500 ${fwcmd} add pass tcp from $i to me $j 501 ;; 502 *) 503 echo "Invalid port in firewall_myservices: $j" > /dev/stderr 504 ;; 505 esac 506 done 507 done 508 509 # Allow all connections from trusted IPs. 510 # Playing with the content of firewall_trusted could seriously 511 # degrade the level of protection provided by the firewall. 512 for i in ${firewall_trusted} ; do 513 ${fwcmd} add pass ip from $i to me 514 done 515 516 ${fwcmd} add 65000 count ip from any to any 517 518 # Drop packets to ports where we don't want logging 519 for i in ${firewall_nologports} ; do 520 ${fwcmd} add deny { tcp or udp } from any to any $i in 521 done 522 523 # Broadcasts and multicasts 524 ${fwcmd} add deny ip from any to 255.255.255.255 525 ${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX 526 527 # Noise from routers 528 ${fwcmd} add deny udp from any to any 520 in 529 530 # Noise from webbrowsing. 531 # The stateful filter is a bit aggressive, and will cause some 532 # connection teardowns to be logged. 533 ${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in 534 535 # Deny and (if wanted) log the rest unconditionally. 536 log="" 537 if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then 538 log="log logamount 500" # The default of 100 is too low. 539 sysctl net.inet.ip.fw.verbose=1 >/dev/null 540 fi 541 ${fwcmd} add deny $log ip from any to any 542 ;; 543 544[Cc][Ll][Oo][Ss][Ee][Dd]) 545 ${fwcmd} add 65000 deny ip from any to any 546 ;; 547[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 548 ;; 549*) 550 if [ -r "${firewall_type}" ]; then 551 ${fwcmd} ${firewall_flags} ${firewall_type} 552 fi 553 ;; 554esac 555