mdw@git.distorted.org.uk Git - firewall/blob - local.m4

   1 ### -*-sh-*-
   2 ###
   3 ### Local firewall configuration
   4 ###
   5 ### (c) 2008 Mark Wooding
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This program is free software; you can redistribute it and/or modify
  11 ### it under the terms of the GNU General Public License as published by
  12 ### the Free Software Foundation; either version 2 of the License, or
  13 ### (at your option) any later version.
  14 ###
  15 ### This program is distributed in the hope that it will be useful,
  16 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ### GNU General Public License for more details.
  19 ###
  20 ### You should have received a copy of the GNU General Public License
  21 ### along with this program; if not, write to the Free Software Foundation,
  22 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23
  24 ###--------------------------------------------------------------------------
  25 ### Local configuration.
  26
  27 m4_divert(6)m4_dnl
  28 ## Default NTP servers.
  29 defconf(ntp_servers,
  30         "158.152.1.76 158.152.1.204 194.159.253.2 195.173.57.232")
  31
  32 m4_divert(-1)
  33 ###--------------------------------------------------------------------------
  34 ### Packet classification.
  35
  36 ## IPv4 addressing.
  37 ##
  38 ## There are two small blocks of publicly routable IPv4 addresses, and a
  39 ## block of RFC1918 private-use addresses allocated from the Cambridge G-RIN.
  40 ## The former are as follows.
  41 ##
  42 ## 81.2.113.195, 81.187.238.128/28
  43 ##              House border network (dmz).  We have all of these; the loose
  44 ##              address is for the router.
  45 ##
  46 ## 212.13.18.64/28
  47 ##              Jump colocated network (jump).  .65--68 are used by Jump
  48 ##              network infrastructure; we get the rest.
  49 ##
  50 ## The latter is the block 172.29.196.0/22.  Currently the low half is
  51 ## unallocated (and may be returned to the G-RIN); the remaining addresses
  52 ## are allocated as follows.
  53 ##
  54 ## 172.29.198.0/24  Untrusted networks.
  55 ##      .0/25           house wireless net
  56 ##      .128/28         iodine (IP-over-DNS) network
  57 ##      .144/28         hippotat (IP-over-HTTP) network
  58 ##      .160/27         untrusted virtual network
  59 ##
  60 ## 172.29.199.0/24  Trusted networks.
  61 ##      .0/25           house wired network
  62 ##      .128/27         mobile VPN hosts
  63 ##      .160/28         reserved, except .160/30 allocated for ITS
  64 ##      .176/28         internal colocated network
  65 ##      .192/27         house safe network
  66 ##      .224/27         anycast services
  67
  68 ## IPv6 addressing.
  69 ##
  70 ## There are five blocks of publicly routable IPv6 addresses, though some of
  71 ## them aren't very interesting.  The ranges are as follows.
  72 ##
  73 ## 2001:8b0:c92::/48
  74 ##              Main house range (aaisp).  See below for allocation policy.
  75 ##              There is no explicit DMZ allocation (and no need for one).
  76 ##
  77 ## 2001:ba8:0:1d9::/64
  78 ##              Jump border network (jump): :1 is the router (supplied by
  79 ##              Jump); other addresses are ours.
  80 ##
  81 ## 2001:ba8:1d9::/48
  82 ##              Main colocated range.  See below for allocation policy.
  83 ##
  84 ## Addresses in the /64 networks are simply allocated in ascending order.
  85 ## The /48s are split into /64s by appending a 16-bit network number.  The
  86 ## top nibble of the network number classifies the network, as follows.
  87 ##
  88 ## axxx         Virtual, untrusted
  89 ## 8xxx         Untrusted
  90 ## 6xxx         Virtual, safe
  91 ## 4xxx         Safe
  92 ## 0xxx         Unsafe, trusted
  93 ##
  94 ## These have been chosen so that network properties can be deduced by
  95 ## inspecting bits of the network number:
  96 ##
  97 ## Bit 15       If set, the network is untrusted; otherwise it is trusted.
  98 ## Bit 14       If set, the network is safe; otherwise it is unsafe.
  99 ##
 100 ## Finally, the low-order nibbles identify the site.
 101 ##
 102 ## 0            No specific site: mobile VPN endpoints or anycast addresses.
 103 ## 1            House.
 104 ## 2            Jump colocation.
 105 ## fff          Local border network.
 106 ##
 107 ## Usually site-0 networks are allocated from the Jump range to improve
 108 ## expected performance from/to external sites which don't engage in our
 109 ## dynamic routing protocols.
 110
 111 ## Define the available network classes.
 112 m4_divert(42)m4_dnl
 113 defnetclass scary       scary           trusted             vpnnat mcast
 114 defnetclass untrusted   scary untrusted trusted                    mcast
 115 defnetclass trusted     scary untrusted trusted safe noloop vpnnat mcast
 116 defnetclass safe                        trusted safe noloop vpnnat mcast
 117 defnetclass noloop                      trusted safe               mcast
 118 defnetclass vpnnat      scary           trusted safe               mcast
 119
 120 defnetclass link
 121 defnetclass mcast
 122 m4_divert(-1)
 123
 124 m4_divert(26)m4_dnl
 125 ###--------------------------------------------------------------------------
 126 ### Network layout.
 127
 128 ## House networks.
 129 defnet dmz trusted
 130         addr 81.2.113.195 81.187.238.128/28 2001:8b0:c92:fff::/64
 131         via unsafe untrusted
 132 defnet unsafe trusted
 133         addr 172.29.199.0/25 2001:8b0:c92:1::/64
 134         via househub
 135 defnet safe safe
 136         addr 172.29.199.192/27 2001:8b0:c92:4001::/64
 137         via househub
 138 defnet untrusted untrusted
 139         addr 172.29.198.0/25 2001:8b0:c92:8001::/64
 140         via househub
 141
 142 defnet househub virtual
 143         via housebdry dmz unsafe safe untrusted
 144 defnet housebdry virtual
 145         via househub hub
 146
 147 ## House hosts.
 148 defhost radius
 149         hosttype router
 150         iface eth0 dmz unsafe safe untrusted vpn sgo colobdry default
 151         iface eth1 dmz unsafe safe untrusted vpn sgo colobdry default
 152         iface eth2 dmz unsafe safe untrusted vpn sgo colobdry
 153         iface eth3 unsafe untrusted vpn default
 154         iface ppp0 default
 155         iface t6-he default
 156         iface vpn-precision colobdry vpn sgo
 157         iface vpn-chiark sgo
 158         iface vpn-+ vpn
 159 defhost roadstar
 160         iface eth0 dmz unsafe
 161         iface eth1 dmz unsafe
 162 defhost jem
 163         iface eth0 dmz unsafe
 164         iface eth1 dmz unsafe
 165 defhost universe
 166         iface eth0 dmz unsafe
 167         iface eth1 dmz unsafe
 168 defhost artist
 169         hosttype router
 170         iface eth0 dmz unsafe untrusted
 171         iface eth1 dmz unsafe untrusted
 172         iface eth3 unsafe untrusted
 173 defhost vampire
 174         hosttype router
 175         iface eth0.4 dmz unsafe untrusted safe vpn sgo colobdry
 176         iface eth0.5 dmz unsafe untrusted safe vpn sgo colobdry
 177         iface eth0.6 dmz unsafe safe untrusted vpn sgo colobdry
 178         iface eth0.7 unsafe untrusted vpn
 179         iface vpn-precision colobdry vpn sgo
 180         iface vpn-chiark sgo
 181         iface vpn-+ vpn
 182 defhost ibanez
 183         iface br-dmz dmz unsafe
 184         iface br-unsafe unsafe
 185 defhost orange
 186         iface wlan0 untrusted
 187         iface vpn-radius unsafe
 188 defhost groove
 189         iface eth0 unsafe
 190         iface wlan0 untrusted
 191         iface vpn-radius unsafe
 192
 193 defhost gibson
 194         hosttype client
 195         iface eth0 unsafe
 196
 197 ## Colocated networks.
 198 defnet jump trusted
 199         addr 212.13.198.64/28 2001:ba8:0:1d9::/64
 200         via colohub
 201 defnet colo trusted
 202         addr 172.29.199.176/28 2001:ba8:1d9:2::/64
 203         via colohub
 204 defnet colohub virtual
 205         via colobdry jump colo
 206 defnet colobdry virtual
 207         via colohub hub
 208 defnet iodine untrusted
 209         addr 172.29.198.128/28
 210         via colohub
 211 defnet hippotat untrusted
 212         addr 172.29.198.144/28
 213         via colohub
 214
 215 ## Colocated hosts.
 216 defhost fender
 217         iface br-jump jump colo
 218         iface br-colo jump colo
 219 defhost precision
 220         hosttype router
 221         iface eth0 jump colo vpn sgo
 222         iface eth1 jump colo vpn sgo
 223         iface vpn-mango binswood
 224         iface vpn-radius housebdry vpn sgo
 225         iface vpn-chiark sgo
 226         iface vpn-national upn
 227         iface vpn-+ vpn
 228 defhost telecaster
 229         iface eth0 jump colo
 230         iface eth1 jump colo
 231 defhost stratocaster
 232         iface eth0 jump colo
 233         iface eth1 jump colo
 234 defhost jazz
 235         hosttype router
 236         iface eth0 jump colo vpn
 237         iface eth1 jump colo vpn
 238         iface dns0 iodine
 239         iface hippo-svc hippotat
 240         iface vpn-+ vpn
 241
 242 ## Other networks.
 243 defnet hub virtual
 244         via housebdry colobdry
 245 defnet sgo noloop
 246         addr !172.29.198.0/23
 247         addr !10.165.27.0/24
 248         addr 10.0.0.0/8
 249         addr 172.16.0.0/12
 250         addr 192.168.0.0/16
 251         via househub colohub
 252 defnet vpn trusted
 253         addr 172.29.199.128/27 2001:ba8:1d9:6000::/64
 254         via househub colohub
 255         host crybaby 1 ::1:1
 256         host terror 2 ::2:1
 257         host orange 3 ::3:1
 258         host haze 4 ::4:1
 259         host groove 5 ::5:1
 260 defnet anycast trusted
 261         addr 172.29.199.224/27 2001:ba8:1d9:0::/64
 262         via dmz unsafe safe untrusted jump colo vpn
 263 defnet default scary
 264         addr 81.2.113.195 81.187.238.128/28 2001:8b0:c92::/48
 265         addr 212.13.198.64/28 2001:ba8:0:1d9::/64
 266         addr 2001:ba8:1d9::/48 #temporary
 267         via dmz unsafe untrusted jump colo
 268 defnet upn untrusted
 269         addr 172.29.198.160/27 2001:ba8:1d9:a000::/64
 270         via colohub
 271         host national 1 ::1:1
 272
 273 ## Linode hosts.
 274 defhost national
 275         iface eth0 default
 276         iface vpn-precision colohub
 277
 278 ## Satellite networks.
 279 defnet binswood vpnnat
 280         addr 10.165.27.0/24
 281         via colohub
 282 defhost mango
 283         hosttype router
 284         iface eth0 binswood default
 285         iface vpn-precision colo default
 286
 287 m4_divert(80)m4_dnl
 288 ###--------------------------------------------------------------------------
 289 ### Connection tracking helper modules.
 290
 291 for i in ftp; do
 292   modprobe nf_conntrack_$i
 293 done
 294
 295 m4_divert(80)m4_dnl
 296 ###--------------------------------------------------------------------------
 297 ### Special forwarding exemptions.
 298
 299 case $forward in
 300   1)
 301
 302     ## Only allow these packets if they're not fragmented.  (Don't trust safe
 303     ## hosts's fragment reassembly to be robust against malicious fragments.)
 304     ## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
 305     ## of `! -f', so we do the negation using early return from a subchain.
 306     clearchain fwd-spec-nofrag
 307     run iptables -A fwd-spec-nofrag -j RETURN --fragment
 308     run ip6tables -A fwd-spec-nofrag -j RETURN \
 309             -m ipv6header --soft --header frag
 310     run ip46tables -A FORWARD -j fwd-spec-nofrag
 311
 312     ## Allow ping from safe/noloop to untrusted networks.
 313     run iptables -A fwd-spec-nofrag -j ACCEPT \
 314             -p icmp --icmp-type echo-request \
 315             -m mark --mark $to_untrusted/$MASK_TO
 316     run iptables -A fwd-spec-nofrag -j ACCEPT \
 317             -p icmp --icmp-type echo-reply \
 318             -m mark --mark $from_untrusted/$MASK_FROM \
 319             -m state --state ESTABLISHED
 320     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 321             -p icmpv6 --icmpv6-type echo-request \
 322             -m mark --mark $to_untrusted/$MASK_TO
 323     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 324             -p icmpv6 --icmpv6-type echo-reply \
 325             -m mark --mark $from_untrusted/$MASK_FROM \
 326             -m state --state ESTABLISHED
 327
 328     ## Allow SSH from safe/noloop to untrusted networks.
 329     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 330             -p tcp --destination-port $port_ssh \
 331             -m mark --mark $to_untrusted/$MASK_TO
 332     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 333             -p tcp --source-port $port_ssh \
 334             -m mark --mark $from_untrusted/$MASK_FROM \
 335             -m state --state ESTABLISHED
 336
 337     ;;
 338 esac
 339
 340 m4_divert(80)m4_dnl
 341 ###--------------------------------------------------------------------------
 342 ### Kill things we don't understand properly.
 343 ###
 344 ### I don't like having to do this, but since I don't know how to do proper
 345 ### multicast filtering, I'm just going to ban it from being forwarded.
 346
 347 errorchain poorly-understood REJECT
 348
 349 ## Ban multicast destination addresses in forwarding.
 350 case $forward in
 351   1)
 352     run iptables -A FORWARD -g poorly-understood \
 353             -d 224.0.0.0/4
 354     run ip6tables -A FORWARD -g poorly-understood \
 355             -d ff::/8
 356     ;;
 357 esac
 358
 359 m4_divert(82)m4_dnl
 360 ###--------------------------------------------------------------------------
 361 ### Check for source routing.
 362
 363 clearchain check-srcroute
 364
 365 run iptables -A check-srcroute -g forbidden \
 366     -m ipv4options --any --flags lsrr,ssrr
 367 run ip6tables -A check-srcroute -g forbidden \
 368     -m rt
 369
 370 for c in INPUT FORWARD; do
 371   for m in $from_scary $from_untrusted; do
 372     run ip46tables -A $c -m mark --mark $m/$MASK_FROM -j check-srcroute
 373   done
 374 done
 375
 376 m4_divert(84)m4_dnl
 377 ###--------------------------------------------------------------------------
 378 ### Locally-bound packet inspection.
 379
 380 clearchain inbound
 381
 382 ## Track connections.
 383 commonrules inbound
 384 conntrack inbound
 385
 386 ## Allow incoming bootp.  Bootp won't be forwarded, so this is obviously a
 387 ## local request.
 388 run iptables -A inbound -j ACCEPT \
 389         -s 0.0.0.0 -d 255.255.255.255 \
 390         -p udp --source-port $port_bootpc --destination-port $port_bootps
 391 run iptables -A inbound -j ACCEPT \
 392         -s 172.29.198.0/23 \
 393         -p udp --source-port $port_bootpc --destination-port $port_bootps
 394
 395 ## Allow incoming ping.  This is the only ICMP left.
 396 run iptables -A inbound -j ACCEPT -p icmp
 397 run ip6tables -A inbound -j ACCEPT -p icmpv6
 398
 399 m4_divert(88)m4_dnl
 400 ## Allow unusual things.
 401 openports inbound
 402
 403 ## Inspect inbound packets from untrusted sources.
 404 run ip46tables -A inbound -g forbidden
 405 run ip46tables -A INPUT -m mark --mark $from_scary/$MASK_FROM -g inbound
 406 run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound
 407
 408 ## Allow responses from the scary outside world into the untrusted net, but
 409 ## don't let untrusted things run services.
 410 case $forward in
 411   1)
 412     run ip46tables -A FORWARD -j ACCEPT \
 413         -m mark --mark $(( $from_scary | $to_untrusted ))/$(( $MASK_FROM | $MASK_TO )) \
 414         -m state --state ESTABLISHED,RELATED
 415     ;;
 416 esac
 417
 418 ## Otherwise process as indicated by the mark.
 419 for i in $inchains; do
 420   run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
 421 done
 422
 423 m4_divert(-1)
 424 ###----- That's all, folks --------------------------------------------------