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             mcast
 114 defnetclass untrusted   scary untrusted trusted             mcast
 115 defnetclass trusted     scary untrusted trusted safe noloop mcast
 116 defnetclass safe                        trusted safe noloop mcast
 117 defnetclass noloop                      trusted safe        mcast
 118
 119 defnetclass link
 120 defnetclass mcast
 121 m4_divert(-1)
 122
 123 m4_divert(26)m4_dnl
 124 ###--------------------------------------------------------------------------
 125 ### Network layout.
 126
 127 ## House networks.
 128 defnet dmz trusted
 129         addr 81.2.113.195 81.187.238.128/28 2001:8b0:c92:fff::/64
 130         via unsafe untrusted
 131 defnet unsafe trusted
 132         addr 172.29.199.0/25 2001:8b0:c92:1::/64
 133         via househub
 134 defnet safe safe
 135         addr 172.29.199.192/27 2001:8b0:c92:4001::/64
 136         via househub
 137 defnet untrusted untrusted
 138         addr 172.29.198.0/25 2001:8b0:c92:8001::/64
 139         via househub
 140
 141 defnet househub virtual
 142         via housebdry dmz unsafe safe untrusted
 143 defnet housebdry virtual
 144         via househub hub
 145
 146 ## House hosts.
 147 defhost radius
 148         hosttype router
 149         iface eth0 dmz unsafe safe untrusted vpn sgo colobdry default
 150         iface eth1 dmz unsafe safe untrusted vpn sgo colobdry default
 151         iface eth2 dmz unsafe safe untrusted vpn sgo colobdry
 152         iface eth3 unsafe untrusted vpn default
 153         iface ppp0 default
 154         iface t6-he default
 155         iface vpn-precision colobdry vpn sgo
 156         iface vpn-chiark sgo
 157         iface vpn-+ vpn
 158 defhost roadstar
 159         iface eth0 dmz unsafe
 160         iface eth1 dmz unsafe
 161 defhost jem
 162         iface eth0 dmz unsafe
 163         iface eth1 dmz unsafe
 164 defhost universe
 165         iface eth0 dmz unsafe
 166         iface eth1 dmz unsafe
 167 defhost artist
 168         hosttype router
 169         iface eth0 dmz unsafe untrusted
 170         iface eth1 dmz unsafe untrusted
 171         iface eth3 unsafe untrusted
 172 defhost vampire
 173         hosttype router
 174         iface eth0.4 dmz unsafe untrusted safe vpn sgo colobdry
 175         iface eth0.5 dmz unsafe untrusted safe vpn sgo colobdry
 176         iface eth0.6 dmz unsafe safe untrusted vpn sgo colobdry
 177         iface eth0.7 unsafe untrusted vpn
 178         iface vpn-precision colobdry vpn sgo
 179         iface vpn-chiark sgo
 180         iface vpn-+ vpn
 181 defhost ibanez
 182         iface br-dmz dmz unsafe
 183         iface br-unsafe unsafe
 184 defhost orange
 185         iface wlan0 untrusted
 186         iface vpn-radius unsafe
 187 defhost groove
 188         iface eth0 unsafe
 189         iface wlan0 untrusted
 190         iface vpn-radius unsafe
 191
 192 defhost gibson
 193         hosttype client
 194         iface eth0 unsafe
 195
 196 ## Colocated networks.
 197 defnet jump trusted
 198         addr 212.13.198.64/28 2001:ba8:0:1d9::/64
 199         via colohub
 200 defnet colo trusted
 201         addr 172.29.199.176/28 2001:ba8:1d9:2::/64
 202         via colohub
 203 defnet colohub virtual
 204         via colobdry jump colo
 205 defnet colobdry virtual
 206         via colohub hub
 207 defnet iodine untrusted
 208         addr 172.29.198.128/28
 209         via colohub
 210 defnet hippotat untrusted
 211         addr 172.29.198.144/28
 212         via colohub
 213
 214 ## Colocated hosts.
 215 defhost fender
 216         iface br-jump jump colo
 217         iface br-colo jump colo
 218 defhost precision
 219         hosttype router
 220         iface eth0 jump colo vpn sgo
 221         iface eth1 jump colo vpn sgo
 222         iface vpn-mango binswood
 223         iface vpn-radius housebdry vpn sgo
 224         iface vpn-chiark sgo
 225         iface vpn-national upn
 226         iface vpn-+ vpn
 227 defhost telecaster
 228         iface eth0 jump colo
 229         iface eth1 jump colo
 230 defhost stratocaster
 231         iface eth0 jump colo
 232         iface eth1 jump colo
 233 defhost jazz
 234         hosttype router
 235         iface eth0 jump colo vpn
 236         iface eth1 jump colo vpn
 237         iface dns0 iodine
 238         iface hippo-svc hippotat
 239         iface vpn-+ vpn
 240
 241 ## Other networks.
 242 defnet hub virtual
 243         via housebdry colobdry
 244 defnet sgo noloop
 245         addr !172.29.198.0/23
 246         addr 10.0.0.0/8
 247         addr 172.16.0.0/12
 248         addr 192.168.0.0/16
 249         via househub colohub
 250 defnet vpn trusted
 251         addr 172.29.199.128/27 2001:ba8:1d9:6000::/64
 252         via househub colohub
 253         host crybaby 1 ::1:1
 254         host terror 2 ::2:1
 255         host orange 3 ::3:1
 256         host haze 4 ::4:1
 257         host groove 5 ::5:1
 258 defnet anycast trusted
 259         addr 172.29.199.224/27 2001:ba8:1d9:0::/64
 260         via dmz unsafe safe untrusted jump colo vpn
 261 defnet default scary
 262         addr 81.2.113.195 81.187.238.128/28 2001:8b0:c92::/48
 263         addr 212.13.198.64/28 2001:ba8:0:1d9::/64
 264         addr 2001:ba8:1d9::/48 #temporary
 265         via dmz unsafe untrusted jump colo
 266 defnet upn untrusted
 267         addr 172.29.198.160/27 2001:ba8:1d9:a000::/64
 268         via colohub
 269         host national 1 ::1:1
 270
 271 ## Linode hosts.
 272 defhost national
 273         iface eth0 default
 274         iface vpn-precision colohub
 275
 276 ## Satellite networks.
 277 defnet binswood noloop
 278         addr 10.165.27.0/24
 279         via colohub
 280 defhost mango
 281         hosttype router
 282         iface eth0 binswood default
 283         iface vpn-precision colo
 284
 285 m4_divert(80)m4_dnl
 286 ###--------------------------------------------------------------------------
 287 ### Connection tracking helper modules.
 288
 289 for i in ftp; do
 290   modprobe nf_conntrack_$i
 291 done
 292
 293 m4_divert(80)m4_dnl
 294 ###--------------------------------------------------------------------------
 295 ### Special forwarding exemptions.
 296
 297 case $forward in
 298   1)
 299
 300     ## Only allow these packets if they're not fragmented.  (Don't trust safe
 301     ## hosts's fragment reassembly to be robust against malicious fragments.)
 302     ## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
 303     ## of `! -f', so we do the negation using early return from a subchain.
 304     clearchain fwd-spec-nofrag
 305     run iptables -A fwd-spec-nofrag -j RETURN --fragment
 306     run ip6tables -A fwd-spec-nofrag -j RETURN \
 307             -m ipv6header --soft --header frag
 308     run ip46tables -A FORWARD -j fwd-spec-nofrag
 309
 310     ## Allow ping from safe/noloop to untrusted networks.
 311     run iptables -A fwd-spec-nofrag -j ACCEPT \
 312             -p icmp --icmp-type echo-request \
 313             -m mark --mark $to_untrusted/$MASK_TO
 314     run iptables -A fwd-spec-nofrag -j ACCEPT \
 315             -p icmp --icmp-type echo-reply \
 316             -m mark --mark $from_untrusted/$MASK_FROM \
 317             -m state --state ESTABLISHED
 318     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 319             -p icmpv6 --icmpv6-type echo-request \
 320             -m mark --mark $to_untrusted/$MASK_TO
 321     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 322             -p icmpv6 --icmpv6-type echo-reply \
 323             -m mark --mark $from_untrusted/$MASK_FROM \
 324             -m state --state ESTABLISHED
 325
 326     ## Allow SSH from safe/noloop to untrusted networks.
 327     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 328             -p tcp --destination-port $port_ssh \
 329             -m mark --mark $to_untrusted/$MASK_TO
 330     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 331             -p tcp --source-port $port_ssh \
 332             -m mark --mark $from_untrusted/$MASK_FROM \
 333             -m state --state ESTABLISHED
 334
 335     ;;
 336 esac
 337
 338 m4_divert(80)m4_dnl
 339 ###--------------------------------------------------------------------------
 340 ### Kill things we don't understand properly.
 341 ###
 342 ### I don't like having to do this, but since I don't know how to do proper
 343 ### multicast filtering, I'm just going to ban it from being forwarded.
 344
 345 errorchain poorly-understood REJECT
 346
 347 ## Ban multicast destination addresses in forwarding.
 348 case $forward in
 349   1)
 350     run iptables -A FORWARD -g poorly-understood \
 351             -d 224.0.0.0/4
 352     run ip6tables -A FORWARD -g poorly-understood \
 353             -d ff::/8
 354     ;;
 355 esac
 356
 357 m4_divert(84)m4_dnl
 358 ###--------------------------------------------------------------------------
 359 ### Locally-bound packet inspection.
 360
 361 clearchain inbound
 362
 363 ## Track connections.
 364 commonrules inbound
 365 conntrack inbound
 366
 367 ## Allow incoming bootp.  Bootp won't be forwarded, so this is obviously a
 368 ## local request.
 369 run iptables -A inbound -j ACCEPT \
 370         -s 0.0.0.0 -d 255.255.255.255 \
 371         -p udp --source-port $port_bootpc --destination-port $port_bootps
 372 run iptables -A inbound -j ACCEPT \
 373         -s 172.29.198.0/23 \
 374         -p udp --source-port $port_bootpc --destination-port $port_bootps
 375
 376 ## Allow incoming ping.  This is the only ICMP left.
 377 run iptables -A inbound -j ACCEPT -p icmp
 378 run ip6tables -A inbound -j ACCEPT -p icmpv6
 379
 380 m4_divert(88)m4_dnl
 381 ## Allow unusual things.
 382 openports inbound
 383
 384 ## Inspect inbound packets from untrusted sources.
 385 run ip46tables -A inbound -g forbidden
 386 run ip46tables -A INPUT -m mark --mark $from_scary/$MASK_FROM -g inbound
 387 run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound
 388
 389 ## Allow responses from the scary outside world into the untrusted net, but
 390 ## don't let untrusted things run services.
 391 case $forward in
 392   1)
 393     run ip46tables -A FORWARD -j ACCEPT \
 394         -m mark --mark $(( $from_scary | $to_untrusted ))/$(( $MASK_FROM | $MASK_TO )) \
 395         -m state --state ESTABLISHED,RELATED
 396     ;;
 397 esac
 398
 399 ## Otherwise process as indicated by the mark.
 400 for i in $inchains; do
 401   run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
 402 done
 403
 404 m4_divert(-1)
 405 ###----- That's all, folks --------------------------------------------------