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 # 27 28 # 29 # Setup system for ipfw(4) firewall service. 30 # 31 32 # Suck in the configuration variables. 33 if [ -z "${source_rc_confs_defined}" ]; then 34 if [ -r /etc/defaults/rc.conf ]; then 35 . /etc/defaults/rc.conf 36 source_rc_confs 37 elif [ -r /etc/rc.conf ]; then 38 . /etc/rc.conf 39 fi 40 fi 41 42 ############ 43 # Define the firewall type in /etc/rc.conf. Valid values are: 44 # open - will allow anyone in 45 # client - will try to protect just this machine 46 # simple - will try to protect a whole network 47 # closed - totally disables IP services except via lo0 interface 48 # workstation - will try to protect just this machine using stateful 49 # firewalling. See below for rc.conf variables used 50 # UNKNOWN - disables the loading of firewall rules. 51 # filename - will load the rules in the given filename (full path required) 52 # 53 # For ``client'' and ``simple'' the entries below should be customized 54 # appropriately. 55 56 ############ 57 # 58 # If you don't know enough about packet filtering, we suggest that you 59 # take time to read this book: 60 # 61 # Building Internet Firewalls, 2nd Edition 62 # Brent Chapman and Elizabeth Zwicky 63 # 64 # O'Reilly & Associates, Inc 65 # ISBN 1-56592-871-7 66 # http://www.ora.com/ 67 # http://www.oreilly.com/catalog/fire2/ 68 # 69 # For a more advanced treatment of Internet Security read: 70 # 71 # Firewalls and Internet Security: Repelling the Wily Hacker, 2nd Edition 72 # William R. Cheswick, Steven M. Bellowin, Aviel D. Rubin 73 # 74 # Addison-Wesley / Prentice Hall 75 # ISBN 0-201-63466-X 76 # http://www.pearsonhighered.com/ 77 # http://www.pearsonhighered.com/educator/academic/product/0,3110,020163466X,00.html 78 # 79 80 setup_loopback() { 81 ############ 82 # Only in rare cases do you want to change these rules 83 # 84 ${fwcmd} add 100 pass all from any to any via lo0 85 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 86 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 87 if [ $ipv6_available -eq 0 ]; then 88 ${fwcmd} add 400 deny all from any to ::1 89 ${fwcmd} add 500 deny all from ::1 to any 90 fi 91 } 92 93 setup_ipv6_mandatory() { 94 [ $ipv6_available -eq 0 ] || return 0 95 96 ############ 97 # Only in rare cases do you want to change these rules 98 # 99 # ND 100 # 101 # DAD 102 ${fwcmd} add pass ipv6-icmp from :: to ff02::/16 103 # RS, RA, NS, NA, redirect... 104 ${fwcmd} add pass ipv6-icmp from fe80::/10 to fe80::/10 105 ${fwcmd} add pass ipv6-icmp from fe80::/10 to ff02::/16 106 107 # Allow ICMPv6 destination unreachable 108 ${fwcmd} add pass ipv6-icmp from any to any icmp6types 1 109 110 # Allow NS/NA/toobig (don't filter it out) 111 ${fwcmd} add pass ipv6-icmp from any to any icmp6types 2,135,136 112 } 113 114 . /etc/rc.subr 115 . /etc/network.subr 116 117 if [ -n "${1}" ]; then 118 firewall_type="${1}" 119 fi 120 if [ -z "${firewall_rc_config_load}" ]; then 121 load_rc_config ipfw 122 else 123 for i in ${firewall_rc_config_load}; do 124 load_rc_config $i 125 done 126 fi 127 128 afexists inet6 129 ipv6_available=$? 130 131 ############ 132 # Set quiet mode if requested 133 # 134 case ${firewall_quiet} in 135 [Yy][Ee][Ss]) 136 fwcmd="/sbin/ipfw -q" 137 ;; 138 *) 139 fwcmd="/sbin/ipfw" 140 ;; 141 esac 142 143 ############ 144 # Flush out the list before we begin. 145 # 146 ${fwcmd} -f flush 147 148 setup_loopback 149 setup_ipv6_mandatory 150 151 ############ 152 # Network Address Translation. All packets are passed to natd(8) 153 # before they encounter your remaining rules. The firewall rules 154 # will then be run again on each packet after translation by natd 155 # starting at the rule number following the divert rule. 156 # 157 # For ``simple'' firewall type the divert rule should be put to a 158 # different place to not interfere with address-checking rules. 159 # 160 case ${firewall_type} in 161 [Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 162 case ${natd_enable} in 163 [Yy][Ee][Ss]) 164 if [ -n "${natd_interface}" ]; then 165 ${fwcmd} add 50 divert natd ip4 from any to any via ${natd_interface} 166 fi 167 ;; 168 esac 169 case ${firewall_nat_enable} in 170 [Yy][Ee][Ss]) 171 if [ -n "${firewall_nat_interface}" ]; then 172 if echo "${firewall_nat_interface}" | \ 173 grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then 174 firewall_nat_flags="ip ${firewall_nat_interface} ${firewall_nat_flags}" 175 else 176 firewall_nat_flags="if ${firewall_nat_interface} ${firewall_nat_flags}" 177 fi 178 ${fwcmd} nat 123 config log ${firewall_nat_flags} 179 ${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface} 180 fi 181 ;; 182 esac 183 esac 184 185 ############ 186 # If you just configured ipfw in the kernel as a tool to solve network 187 # problems or you just want to disallow some particular kinds of traffic 188 # then you will want to change the default policy to open. You can also 189 # do this as your only action by setting the firewall_type to ``open''. 190 # 191 # ${fwcmd} add 65000 pass all from any to any 192 193 194 # Prototype setups. 195 # 196 case ${firewall_type} in 197 [Oo][Pp][Ee][Nn]) 198 ${fwcmd} add 65000 pass all from any to any 199 ;; 200 201 [Cc][Ll][Ii][Ee][Nn][Tt]) 202 ############ 203 # This is a prototype setup that will protect your system somewhat 204 # against people from outside your own network. 205 # 206 # Configuration: 207 # firewall_client_net: Network address of local IPv4 network. 208 # firewall_client_net_ipv6: Network address of local IPv6 network. 209 ############ 210 211 # set this to your local network 212 net="$firewall_client_net" 213 net6="$firewall_client_net_ipv6" 214 215 # Allow limited broadcast traffic from my own net. 216 ${fwcmd} add pass all from ${net} to 255.255.255.255 217 218 # Allow any traffic to or from my own net. 219 ${fwcmd} add pass all from me to ${net} 220 ${fwcmd} add pass all from ${net} to me 221 if [ -n "$net6" ]; then 222 ${fwcmd} add pass all from me to ${net6} 223 ${fwcmd} add pass all from ${net6} to me 224 # Allow any link-local multicast traffic 225 ${fwcmd} add pass all from fe80::/10 to ff02::/16 226 ${fwcmd} add pass all from ${net6} to ff02::/16 227 # Allow DHCPv6 228 ${fwcmd} add pass udp from fe80::/10 to me 546 229 fi 230 231 # Allow TCP through if setup succeeded 232 ${fwcmd} add pass tcp from any to any established 233 234 # Allow IP fragments to pass through 235 ${fwcmd} add pass all from any to any frag 236 237 # Allow setup of incoming email 238 ${fwcmd} add pass tcp from any to me 25 setup 239 240 # Allow setup of outgoing TCP connections only 241 ${fwcmd} add pass tcp from me to any setup 242 243 # Disallow setup of all other TCP connections 244 ${fwcmd} add deny tcp from any to any setup 245 246 # Allow DNS queries out in the world 247 ${fwcmd} add pass udp from me to any 53 keep-state 248 249 # Allow NTP queries out in the world 250 ${fwcmd} add pass udp from me to any 123 keep-state 251 252 # Everything else is denied by default, unless the 253 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 254 # config file. 255 ;; 256 257 [Ss][Ii][Mm][Pp][Ll][Ee]) 258 ############ 259 # This is a prototype setup for a simple firewall. Configure this 260 # machine as a DNS and NTP server, and point all the machines 261 # on the inside at this machine for those services. 262 # 263 # Configuration: 264 # firewall_simple_iif: Inside IPv4 network interface. 265 # firewall_simple_inet: Inside IPv4 network address. 266 # firewall_simple_oif: Outside IPv4 network interface. 267 # firewall_simple_onet: Outside IPv4 network address. 268 # firewall_simple_iif_ipv6: Inside IPv6 network interface. 269 # firewall_simple_inet_ipv6: Inside IPv6 network prefix. 270 # firewall_simple_oif_ipv6: Outside IPv6 network interface. 271 # firewall_simple_onet_ipv6: Outside IPv6 network prefix. 272 ############ 273 BAD_ADDR_TBL=13 274 275 # set these to your outside interface network 276 oif="$firewall_simple_oif" 277 onet="$firewall_simple_onet" 278 oif6="${firewall_simple_oif_ipv6:-$firewall_simple_oif}" 279 onet6="$firewall_simple_onet_ipv6" 280 281 # set these to your inside interface network 282 iif="$firewall_simple_iif" 283 inet="$firewall_simple_inet" 284 iif6="${firewall_simple_iif_ipv6:-$firewall_simple_iif}" 285 inet6="$firewall_simple_inet_ipv6" 286 287 # Stop spoofing 288 ${fwcmd} add deny all from ${inet} to any in via ${oif} 289 ${fwcmd} add deny all from ${onet} to any in via ${iif} 290 if [ -n "$inet6" ]; then 291 ${fwcmd} add deny all from ${inet6} to any in via ${oif6} 292 if [ -n "$onet6" ]; then 293 ${fwcmd} add deny all from ${onet6} to any in \ 294 via ${iif6} 295 fi 296 fi 297 298 # Define stuff we should never send out or receive in. 299 # Stop RFC1918 nets on the outside interface 300 ${fwcmd} table ${BAD_ADDR_TBL} flush 301 ${fwcmd} table ${BAD_ADDR_TBL} add 10.0.0.0/8 302 ${fwcmd} table ${BAD_ADDR_TBL} add 172.16.0.0/12 303 ${fwcmd} table ${BAD_ADDR_TBL} add 192.168.0.0/16 304 305 # And stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 306 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 307 # on the outside interface 308 ${fwcmd} table ${BAD_ADDR_TBL} add 0.0.0.0/8 309 ${fwcmd} table ${BAD_ADDR_TBL} add 169.254.0.0/16 310 ${fwcmd} table ${BAD_ADDR_TBL} add 192.0.2.0/24 311 ${fwcmd} table ${BAD_ADDR_TBL} add 224.0.0.0/4 312 ${fwcmd} table ${BAD_ADDR_TBL} add 240.0.0.0/4 313 314 ${fwcmd} add deny all from any to "table($BAD_ADDR_TBL)" via ${oif} 315 316 # Network Address Translation. This rule is placed here deliberately 317 # so that it does not interfere with the surrounding address-checking 318 # rules. If for example one of your internal LAN machines had its IP 319 # address set to 192.0.2.1 then an incoming packet for it after being 320 # translated by natd(8) would match the `deny' rule above. Similarly 321 # an outgoing packet originated from it before being translated would 322 # match the `deny' rule below. 323 case ${natd_enable} in 324 [Yy][Ee][Ss]) 325 if [ -n "${natd_interface}" ]; then 326 ${fwcmd} add divert natd ip4 from any to any via ${natd_interface} 327 fi 328 ;; 329 esac 330 331 ${fwcmd} add deny all from "table($BAD_ADDR_TBL)" to any via ${oif} 332 if [ -n "$inet6" ]; then 333 # Stop unique local unicast address on the outside interface 334 ${fwcmd} add deny all from fc00::/7 to any via ${oif6} 335 ${fwcmd} add deny all from any to fc00::/7 via ${oif6} 336 337 # Stop site-local on the outside interface 338 ${fwcmd} add deny all from fec0::/10 to any via ${oif6} 339 ${fwcmd} add deny all from any to fec0::/10 via ${oif6} 340 341 # Disallow "internal" addresses to appear on the wire. 342 ${fwcmd} add deny all from ::ffff:0.0.0.0/96 to any \ 343 via ${oif6} 344 ${fwcmd} add deny all from any to ::ffff:0.0.0.0/96 \ 345 via ${oif6} 346 347 # Disallow packets to malicious IPv4 compatible prefix. 348 ${fwcmd} add deny all from ::224.0.0.0/100 to any via ${oif6} 349 ${fwcmd} add deny all from any to ::224.0.0.0/100 via ${oif6} 350 ${fwcmd} add deny all from ::127.0.0.0/104 to any via ${oif6} 351 ${fwcmd} add deny all from any to ::127.0.0.0/104 via ${oif6} 352 ${fwcmd} add deny all from ::0.0.0.0/104 to any via ${oif6} 353 ${fwcmd} add deny all from any to ::0.0.0.0/104 via ${oif6} 354 ${fwcmd} add deny all from ::255.0.0.0/104 to any via ${oif6} 355 ${fwcmd} add deny all from any to ::255.0.0.0/104 via ${oif6} 356 357 ${fwcmd} add deny all from ::0.0.0.0/96 to any via ${oif6} 358 ${fwcmd} add deny all from any to ::0.0.0.0/96 via ${oif6} 359 360 # Disallow packets to malicious 6to4 prefix. 361 ${fwcmd} add deny all from 2002:e000::/20 to any via ${oif6} 362 ${fwcmd} add deny all from any to 2002:e000::/20 via ${oif6} 363 ${fwcmd} add deny all from 2002:7f00::/24 to any via ${oif6} 364 ${fwcmd} add deny all from any to 2002:7f00::/24 via ${oif6} 365 ${fwcmd} add deny all from 2002:0000::/24 to any via ${oif6} 366 ${fwcmd} add deny all from any to 2002:0000::/24 via ${oif6} 367 ${fwcmd} add deny all from 2002:ff00::/24 to any via ${oif6} 368 ${fwcmd} add deny all from any to 2002:ff00::/24 via ${oif6} 369 370 ${fwcmd} add deny all from 2002:0a00::/24 to any via ${oif6} 371 ${fwcmd} add deny all from any to 2002:0a00::/24 via ${oif6} 372 ${fwcmd} add deny all from 2002:ac10::/28 to any via ${oif6} 373 ${fwcmd} add deny all from any to 2002:ac10::/28 via ${oif6} 374 ${fwcmd} add deny all from 2002:c0a8::/32 to any via ${oif6} 375 ${fwcmd} add deny all from any to 2002:c0a8::/32 via ${oif6} 376 377 ${fwcmd} add deny all from ff05::/16 to any via ${oif6} 378 ${fwcmd} add deny all from any to ff05::/16 via ${oif6} 379 fi 380 381 # Allow TCP through if setup succeeded 382 ${fwcmd} add pass tcp from any to any established 383 384 # Allow IP fragments to pass through 385 ${fwcmd} add pass all from any to any frag 386 387 # Allow setup of incoming email 388 ${fwcmd} add pass tcp from any to me 25 setup 389 390 # Allow access to our DNS 391 ${fwcmd} add pass tcp from any to me 53 setup 392 ${fwcmd} add pass udp from any to me 53 393 ${fwcmd} add pass udp from me 53 to any 394 395 # Allow access to our WWW 396 ${fwcmd} add pass tcp from any to me 80 setup 397 398 # Reject&Log all setup of incoming connections from the outside 399 ${fwcmd} add deny log ip4 from any to any in via ${oif} setup proto tcp 400 if [ -n "$inet6" ]; then 401 ${fwcmd} add deny log ip6 from any to any in via ${oif6} \ 402 setup proto tcp 403 fi 404 405 # Allow setup of any other TCP connection 406 ${fwcmd} add pass tcp from any to any setup 407 408 # Allow DNS queries out in the world 409 ${fwcmd} add pass udp from me to any 53 keep-state 410 411 # Allow NTP queries out in the world 412 ${fwcmd} add pass udp from me to any 123 keep-state 413 414 # Everything else is denied by default, unless the 415 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 416 # config file. 417 ;; 418 419 [Ww][Oo][Rr][Kk][Ss][Tt][Aa][Tt][Ii][Oo][Nn]) 420 # Configuration: 421 # firewall_myservices: List of ports/protocols on which this 422 # host offers services. 423 # firewall_allowservices: List of IPv4 and/or IPv6 addresses 424 # that have access to 425 # $firewall_myservices. 426 # firewall_trusted: List of IPv4 and/or IPv6 addresses 427 # that have full access to this host. 428 # Be very careful when setting this. 429 # This option can seriously degrade 430 # the level of protection provided by 431 # the firewall. 432 # firewall_logdeny: Boolean (YES/NO) specifying if the 433 # default denied packets should be 434 # logged (in /var/log/security). 435 # firewall_nologports: List of TCP/UDP ports for which 436 # denied incoming packets are not 437 # logged. 438 439 # Allow packets for which a state has been built. 440 ${fwcmd} add check-state 441 442 # For services permitted below. 443 ${fwcmd} add pass tcp from me to any established 444 445 # Allow any connection out, adding state for each. 446 ${fwcmd} add pass tcp from me to any setup keep-state 447 ${fwcmd} add pass udp from me to any keep-state 448 ${fwcmd} add pass icmp from me to any keep-state 449 if [ $ipv6_available -eq 0 ]; then 450 ${fwcmd} add pass ipv6-icmp from me to any keep-state 451 fi 452 453 # Allow DHCP. 454 ${fwcmd} add pass udp from 0.0.0.0 68 to 255.255.255.255 67 out 455 ${fwcmd} add pass udp from any 67 to me 68 in 456 ${fwcmd} add pass udp from any 67 to 255.255.255.255 68 in 457 if [ $ipv6_available -eq 0 ]; then 458 ${fwcmd} add pass udp from fe80::/10 to me 546 in 459 fi 460 # Some servers will ping the IP while trying to decide if it's 461 # still in use. 462 ${fwcmd} add pass icmp from any to any icmptype 8 463 if [ $ipv6_available -eq 0 ]; then 464 ${fwcmd} add pass ipv6-icmp from any to any icmp6type 128,129 465 fi 466 467 # Allow "mandatory" ICMP in. 468 ${fwcmd} add pass icmp from any to any icmptype 3,4,11 469 if [ $ipv6_available -eq 0 ]; then 470 ${fwcmd} add pass ipv6-icmp from any to any icmp6type 3 471 fi 472 473 # Add permits for this workstations published services below 474 # Only IPs and nets in firewall_allowservices is allowed in. 475 # If you really wish to let anyone use services on your 476 # workstation, then set "firewall_allowservices='any'" in /etc/rc.conf 477 # 478 # Note: We don't use keep-state as that would allow DoS of 479 # our statetable. 480 # You can add 'keep-state' to the lines for slightly 481 # better performance if you fell that DoS of your 482 # workstation won't be a problem. 483 # 484 for i in ${firewall_allowservices} ; do 485 for j in ${firewall_myservices} ; do 486 case $j in 487 [0-9A-Za-z]*/[Pp][Rr][Oo][Tt][Oo]) 488 ${fwcmd} add pass ${j%/[Pp][Rr][Oo][Tt][Oo]} from $i to me 489 ;; 490 [0-9A-Za-z]*/[Tt][Cc][Pp]) 491 ${fwcmd} add pass tcp from $i to me ${j%/[Tt][Cc][Pp]} 492 ;; 493 [0-9A-Za-z]*/[Uu][Dd][Pp]) 494 ${fwcmd} add pass udp from $i to me ${j%/[Uu][Dd][Pp]} 495 ;; 496 *[0-9A-Za-z]) 497 echo "Consider using ${j}/tcp in firewall_myservices." \ 498 > /dev/stderr 499 ${fwcmd} add pass tcp from $i to me $j 500 ;; 501 *) 502 echo "Invalid port in firewall_myservices: $j" > /dev/stderr 503 ;; 504 esac 505 done 506 done 507 508 # Allow all connections from trusted IPs. 509 # Playing with the content of firewall_trusted could seriously 510 # degrade the level of protection provided by the firewall. 511 for i in ${firewall_trusted} ; do 512 ${fwcmd} add pass ip from $i to me 513 done 514 515 ${fwcmd} add 65000 count ip from any to any 516 517 # Drop packets to ports where we don't want logging 518 for i in ${firewall_nologports} ; do 519 ${fwcmd} add deny { tcp or udp } from any to any $i in 520 done 521 522 # Broadcasts and multicasts 523 ${fwcmd} add deny ip from any to 255.255.255.255 524 ${fwcmd} add deny ip from any to 224.0.0.0/24 in # XXX 525 526 # Noise from routers 527 ${fwcmd} add deny udp from any to any 520 in 528 529 # Noise from webbrowsing. 530 # The stateful filter is a bit aggressive, and will cause some 531 # connection teardowns to be logged. 532 ${fwcmd} add deny tcp from any 80,443 to any 1024-65535 in 533 534 # Deny and (if wanted) log the rest unconditionally. 535 log="" 536 if [ ${firewall_logdeny:-x} = "YES" -o ${firewall_logdeny:-x} = "yes" ] ; then 537 log="log logamount 500" # The default of 100 is too low. 538 sysctl net.inet.ip.fw.verbose=1 >/dev/null 539 fi 540 ${fwcmd} add deny $log ip from any to any 541 ;; 542 543 [Cc][Ll][Oo][Ss][Ee][Dd]) 544 ${fwcmd} add 65000 deny ip from any to any 545 ;; 546 [Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 547 ;; 548 *) 549 if [ -r "${firewall_type}" ]; then 550 ${fwcmd} ${firewall_flags} ${firewall_type} 551 fi 552 ;; 553 esac 554