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         "81.187.26.174 90.155.23.205 2001:8b0:0:23::205 185.73.44.6 2001:ba8:0:2c06::")
  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         host spirit 9 ::9:1
 261 defnet anycast trusted
 262         addr 172.29.199.224/27 2001:ba8:1d9:0::/64
 263         via dmz unsafe safe untrusted jump colo vpn
 264 defnet default scary
 265         addr 81.2.113.195 81.187.238.128/28 2001:8b0:c92::/48
 266         addr 212.13.198.64/28 2001:ba8:0:1d9::/64
 267         addr 2001:ba8:1d9::/48 #temporary
 268         via dmz unsafe untrusted jump colo
 269 defnet upn untrusted
 270         addr 172.29.198.160/27 2001:ba8:1d9:a000::/64
 271         via colohub
 272         host national 1 ::1:1
 273
 274 ## Linode hosts.
 275 defhost national
 276         iface eth0 default
 277         iface vpn-precision colohub
 278
 279 ## Satellite networks.
 280 defnet binswood vpnnat
 281         addr 10.165.27.0/24
 282         via colohub
 283 defhost mango
 284         hosttype router
 285         iface eth0 binswood default
 286         iface vpn-precision colo default
 287
 288 m4_divert(80)m4_dnl
 289 ###--------------------------------------------------------------------------
 290 ### Connection tracking helper modules.
 291
 292 for i in ftp; do
 293   modprobe nf_conntrack_$i
 294 done
 295
 296 m4_divert(80)m4_dnl
 297 ###--------------------------------------------------------------------------
 298 ### Special forwarding exemptions.
 299
 300 case $forward in
 301   1)
 302
 303     ## Only allow these packets if they're not fragmented.  (Don't trust safe
 304     ## hosts's fragment reassembly to be robust against malicious fragments.)
 305     ## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
 306     ## of `! -f', so we do the negation using early return from a subchain.
 307     clearchain fwd-spec-nofrag
 308     run iptables -A fwd-spec-nofrag -j RETURN --fragment
 309     run ip6tables -A fwd-spec-nofrag -j RETURN \
 310             -m ipv6header --soft --header frag
 311     run ip46tables -A FORWARD -j fwd-spec-nofrag
 312
 313     ## Allow ping from safe/noloop to untrusted networks.
 314     run iptables -A fwd-spec-nofrag -j ACCEPT \
 315             -p icmp --icmp-type echo-request \
 316             -m mark --mark $to_untrusted/$MASK_TO
 317     run iptables -A fwd-spec-nofrag -j ACCEPT \
 318             -p icmp --icmp-type echo-reply \
 319             -m mark --mark $from_untrusted/$MASK_FROM \
 320             -m state --state ESTABLISHED
 321     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 322             -p icmpv6 --icmpv6-type echo-request \
 323             -m mark --mark $to_untrusted/$MASK_TO
 324     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 325             -p icmpv6 --icmpv6-type echo-reply \
 326             -m mark --mark $from_untrusted/$MASK_FROM \
 327             -m state --state ESTABLISHED
 328
 329     ## Allow SSH from safe/noloop to untrusted networks.
 330     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 331             -p tcp --destination-port $port_ssh \
 332             -m mark --mark $to_untrusted/$MASK_TO
 333     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 334             -p tcp --source-port $port_ssh \
 335             -m mark --mark $from_untrusted/$MASK_FROM \
 336             -m state --state ESTABLISHED
 337
 338     ;;
 339 esac
 340
 341 m4_divert(80)m4_dnl
 342 ###--------------------------------------------------------------------------
 343 ### Kill things we don't understand properly.
 344 ###
 345 ### I don't like having to do this, but since I don't know how to do proper
 346 ### multicast filtering, I'm just going to ban it from being forwarded.
 347
 348 errorchain poorly-understood REJECT
 349
 350 ## Ban multicast destination addresses in forwarding.
 351 case $forward in
 352   1)
 353     run iptables -A FORWARD -g poorly-understood \
 354             -d 224.0.0.0/4
 355     run ip6tables -A FORWARD -g poorly-understood \
 356             -d ff::/8
 357     ;;
 358 esac
 359
 360 m4_divert(82)m4_dnl
 361 ###--------------------------------------------------------------------------
 362 ### Check for source routing.
 363
 364 clearchain check-srcroute
 365
 366 run iptables -A check-srcroute -g forbidden \
 367     -m ipv4options --any --flags lsrr,ssrr
 368 run ip6tables -A check-srcroute -g forbidden \
 369     -m rt
 370
 371 for c in INPUT FORWARD; do
 372   for m in $from_scary $from_untrusted; do
 373     run ip46tables -A $c -m mark --mark $m/$MASK_FROM -j check-srcroute
 374   done
 375 done
 376
 377 m4_divert(84)m4_dnl
 378 ###--------------------------------------------------------------------------
 379 ### Locally-bound packet inspection.
 380
 381 clearchain inbound
 382
 383 ## Track connections.
 384 commonrules inbound
 385 conntrack inbound
 386
 387 ## Allow incoming bootp.  Bootp won't be forwarded, so this is obviously a
 388 ## local request.
 389 run iptables -A inbound -j ACCEPT \
 390         -s 0.0.0.0 -d 255.255.255.255 \
 391         -p udp --source-port $port_bootpc --destination-port $port_bootps
 392 run iptables -A inbound -j ACCEPT \
 393         -s 172.29.198.0/23 \
 394         -p udp --source-port $port_bootpc --destination-port $port_bootps
 395
 396 ## Allow incoming ping.  This is the only ICMP left.
 397 run iptables -A inbound -j ACCEPT -p icmp
 398 run ip6tables -A inbound -j ACCEPT -p icmpv6
 399
 400 m4_divert(88)m4_dnl
 401 ## Allow unusual things.
 402 openports inbound
 403
 404 ## Inspect inbound packets from untrusted sources.
 405 run ip46tables -A inbound -g forbidden
 406 run ip46tables -A INPUT -m mark --mark $from_scary/$MASK_FROM -g inbound
 407 run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound
 408
 409 ## Allow responses from the scary outside world into the untrusted net, but
 410 ## don't let untrusted things run services.
 411 case $forward in
 412   1)
 413     run ip46tables -A FORWARD -j ACCEPT \
 414         -m mark --mark $(( $from_scary | $to_untrusted ))/$(( $MASK_FROM | $MASK_TO )) \
 415         -m state --state ESTABLISHED,RELATED
 416     ;;
 417 esac
 418
 419 ## Otherwise process as indicated by the mark.
 420 for i in $inchains; do
 421   run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
 422 done
 423
 424 m4_divert(-1)
 425 ###----- That's all, folks --------------------------------------------------