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, 217.169.12.64/28
  43 ##              House border network (dmz).  We have all of these; the loose
  44 ##              address is for the router.
  45 ##
  46 ## The latter is the block 172.29.196.0/22.  Currently the low half is
  47 ## unallocated (and may be returned to the G-RIN); the remaining addresses
  48 ## are allocated as follows.
  49 ##
  50 ## 172.29.198.0/24  Untrusted networks.
  51 ##      .0/25           house wireless net
  52 ##      .128/28         iodine (IP-over-DNS) network
  53 ##      .144/28         hippotat (IP-over-HTTP) network
  54 ##      .160/27         untrusted virtual network
  55 ##
  56 ## 172.29.199.0/24  Trusted networks.
  57 ##      .0/25           house wired network
  58 ##      .128/27         mobile VPN hosts
  59 ##      .160/28         reserved, except .160/30 allocated for ITS
  60 ##      .176/28         internal colocated network
  61 ##      .192/27         house safe network
  62 ##      .224/27         anycast services
  63
  64 ## IPv6 addressing.
  65 ##
  66 ## There are five blocks of publicly routable IPv6 addresses, though some of
  67 ## them aren't very interesting.  The ranges are as follows.
  68 ##
  69 ## 2001:8b0:c92::/48
  70 ##              Main house range (aaisp).  See below for allocation policy.
  71 ##              There is no explicit DMZ allocation (and no need for one).
  72 ##
  73 ## Addresses in the /64 networks are simply allocated in ascending order.
  74 ## The /48s are split into /64s by appending a 16-bit network number.  The
  75 ## top nibble of the network number classifies the network, as follows.
  76 ##
  77 ## axxx         Virtual, untrusted
  78 ## 8xxx         Untrusted
  79 ## 6xxx         Virtual, safe
  80 ## 4xxx         Safe
  81 ## 0xxx         Unsafe, trusted
  82 ##
  83 ## These have been chosen so that network properties can be deduced by
  84 ## inspecting bits of the network number:
  85 ##
  86 ## Bit 15       If set, the network is untrusted; otherwise it is trusted.
  87 ## Bit 14       If set, the network is safe; otherwise it is unsafe.
  88 ##
  89 ## Finally, the low-order nibbles identify the site.
  90 ##
  91 ## 0            No specific site: mobile VPN endpoints or anycast addresses.
  92 ## 1            House.
  93 ## fff          Local border network.
  94
  95 ## Define the available network classes.
  96 m4_divert(42)m4_dnl
  97 defnetclass scary       scary           trusted             vpnnat mcast
  98 defnetclass untrusted   scary untrusted trusted                    mcast
  99 defnetclass trusted     scary untrusted trusted safe noloop vpnnat mcast
 100 defnetclass safe                        trusted safe noloop vpnnat mcast
 101 defnetclass noloop                      trusted safe               mcast
 102 defnetclass vpnnat      scary           trusted safe               mcast
 103
 104 defnetclass link
 105 defnetclass mcast
 106 m4_divert(-1)
 107
 108 m4_divert(26)m4_dnl
 109 ###--------------------------------------------------------------------------
 110 ### Network layout.
 111
 112 ## House networks.
 113 defnet dmz trusted
 114         addr 81.2.113.195 81.187.238.128/28 217.169.12.64/28 2001:8b0:c92:fff::/64
 115         via unsafe untrusted
 116 defnet unsafe trusted
 117         addr 172.29.199.0/25 2001:8b0:c92:1::/64
 118         via househub
 119 defnet safe safe
 120         addr 172.29.199.192/27 2001:8b0:c92:4001::/64
 121         via househub
 122 defnet untrusted untrusted
 123         addr 172.29.198.0/25 2001:8b0:c92:8001::/64
 124         via househub
 125
 126 defnet househub virtual
 127         via housebdry dmz unsafe safe untrusted
 128 defnet housebdry virtual
 129         via househub hub
 130
 131 ## House hosts.
 132 defhost radius
 133         hosttype router
 134         iface eth0 dmz unsafe safe untrusted vpn sgo default
 135         iface eth1 dmz unsafe safe untrusted vpn sgo default
 136         iface eth2 dmz unsafe safe untrusted vpn sgo
 137         iface eth3 unsafe untrusted vpn default
 138         iface ppp0 default
 139         iface t6-he default
 140         iface vpn-precision vpn sgo
 141         iface vpn-chiark sgo
 142         iface vpn-+ vpn
 143 defhost roadstar
 144         iface eth0 dmz unsafe
 145         iface eth1 dmz unsafe
 146 defhost jem
 147         iface eth0 dmz unsafe
 148         iface eth1 dmz unsafe
 149 defhost universe
 150         iface eth0 dmz unsafe
 151         iface eth1 dmz unsafe
 152 defhost artist
 153         hosttype router
 154         iface eth0 dmz unsafe untrusted
 155         iface eth1 dmz unsafe untrusted
 156         iface eth3 unsafe untrusted
 157 defhost vampire
 158         hosttype router
 159         iface eth0.4 dmz unsafe untrusted safe vpn sgo
 160         iface eth0.5 dmz unsafe untrusted safe vpn sgo
 161         iface eth0.6 dmz unsafe safe untrusted vpn sgo
 162         iface eth0.7 unsafe untrusted vpn
 163         iface vpn-precision vpn sgo
 164         iface vpn-chiark sgo
 165         iface vpn-+ vpn
 166 defhost ibanez
 167         iface br-dmz dmz unsafe
 168         iface br-unsafe unsafe
 169 defhost orange
 170         iface wlan0 untrusted
 171         iface vpn-radius unsafe
 172 defhost groove
 173         iface eth0 unsafe
 174         iface wlan0 untrusted
 175         iface vpn-radius unsafe
 176
 177 defhost gibson
 178         hosttype client
 179         iface eth0 unsafe
 180
 181 ## Formerly colocated hosts.
 182 defhost fender
 183         iface br-dmz dmz unsafe
 184         iface br-unsafe dmz unsafe
 185 defhost precision
 186         hosttype router
 187         iface eth0 dmz unsafe vpn sgo
 188         iface eth1 dmz unsafe vpn sgo
 189         iface vpn-mango binswood
 190         iface vpn-chiark sgo
 191         iface vpn-national upn
 192         iface vpn-mdwdev upn
 193         iface vpn-+ vpn
 194 defhost telecaster
 195         iface eth0 dmz unsafe vpn sgo
 196         iface eth1 dmz unsafe vpn sgo
 197 defhost stratocaster
 198         iface eth0 dmz unsafe vpn sgo
 199         iface eth1 dmz unsafe vpn sgo
 200 defhost jazz
 201         hosttype router
 202         iface eth0 dmz unsafe vpn sgo
 203         iface eth1 dmz unsafe vpn sgo
 204         iface dns0 iodine
 205         iface hippo-svc hippotat
 206         iface vpn-+ vpn
 207
 208 ## Stunt connectivity networks.
 209 defnet iodine untrusted
 210         addr 172.29.198.128/28
 211         via colohub
 212 defnet hippotat untrusted
 213         addr 172.29.198.144/28
 214         via colohub
 215
 216
 217 ## Other networks.
 218 defnet hub virtual
 219         via housebdry
 220 defnet sgo noloop
 221         addr !172.29.198.0/23
 222         addr !10.165.27.0/24
 223         addr 10.0.0.0/8
 224         addr 172.16.0.0/12
 225         addr 192.168.0.0/16
 226         via househub
 227 defnet vpn trusted
 228         addr 172.29.199.128/27 2001:8b0:c92:6000::/64
 229         via househub
 230         host crybaby 1 ::1:1
 231         host terror 2 ::2:1
 232         host orange 3 ::3:1
 233         host haze 4 ::4:1
 234         host spirit 9 ::9:1
 235         host groove 10 ::10:1
 236 defnet anycast trusted
 237         addr 172.29.199.224/27 2001:8b0:c92:0::/64
 238         via dmz unsafe safe untrusted vpn nvpn
 239 defnet default scary
 240         addr 81.2.113.195 81.187.238.128/28 217.169.12.64/28 \
 241                 2001:8b0:c92::/48
 242         via dmz unsafe untrusted
 243 defnet upn untrusted
 244         addr 172.29.198.160/27 2001:8b0:c92:a000::/64
 245         via househub
 246         host national 1 ::1:1
 247         host mdwdev 2 ::2:1
 248
 249 ## Linode hosts.
 250 defhost national
 251         iface eth0 default
 252         iface vpn-precision househub
 253
 254 ## Satellite networks.
 255 defnet binswood vpnnat
 256         addr 10.165.27.0/24
 257         via househub
 258 defhost mango
 259         hosttype router
 260         iface eth0 binswood default
 261         iface vpn-precision dmz default
 262
 263 m4_divert(80)m4_dnl
 264 ###--------------------------------------------------------------------------
 265 ### Connection tracking helper modules.
 266
 267 for i in ftp; do
 268   modprobe nf_conntrack_$i
 269 done
 270
 271 m4_divert(80)m4_dnl
 272 ###--------------------------------------------------------------------------
 273 ### Special forwarding exemptions.
 274
 275 case $forward in
 276   1)
 277
 278     ## Only allow these packets if they're not fragmented.  (Don't trust safe
 279     ## hosts's fragment reassembly to be robust against malicious fragments.)
 280     ## There's a hideous bug in iptables 1.4.11.1 which botches the meaning
 281     ## of `! -f', so we do the negation using early return from a subchain.
 282     clearchain fwd-spec-nofrag
 283     run iptables -A fwd-spec-nofrag -j RETURN --fragment
 284     run ip6tables -A fwd-spec-nofrag -j RETURN \
 285             -m ipv6header --soft --header frag
 286     run ip46tables -A FORWARD -j fwd-spec-nofrag
 287
 288     ## Allow ping from safe/noloop to untrusted networks.
 289     run iptables -A fwd-spec-nofrag -j ACCEPT \
 290             -p icmp --icmp-type echo-request \
 291             -m mark --mark $to_untrusted/$MASK_TO
 292     run iptables -A fwd-spec-nofrag -j ACCEPT \
 293             -p icmp --icmp-type echo-reply \
 294             -m mark --mark $from_untrusted/$MASK_FROM \
 295             -m state --state ESTABLISHED
 296     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 297             -p icmpv6 --icmpv6-type echo-request \
 298             -m mark --mark $to_untrusted/$MASK_TO
 299     run ip6tables -A fwd-spec-nofrag -j ACCEPT \
 300             -p icmpv6 --icmpv6-type echo-reply \
 301             -m mark --mark $from_untrusted/$MASK_FROM \
 302             -m state --state ESTABLISHED
 303
 304     ## Allow SSH from safe/noloop to untrusted networks.
 305     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 306             -p tcp --destination-port $port_ssh \
 307             -m mark --mark $to_untrusted/$MASK_TO
 308     run ip46tables -A fwd-spec-nofrag -j ACCEPT \
 309             -p tcp --source-port $port_ssh \
 310             -m mark --mark $from_untrusted/$MASK_FROM \
 311             -m state --state ESTABLISHED
 312
 313     ;;
 314 esac
 315
 316 m4_divert(80)m4_dnl
 317 ###--------------------------------------------------------------------------
 318 ### Kill things we don't understand properly.
 319 ###
 320 ### I don't like having to do this, but since I don't know how to do proper
 321 ### multicast filtering, I'm just going to ban it from being forwarded.
 322
 323 errorchain poorly-understood REJECT
 324
 325 ## Ban multicast destination addresses in forwarding.
 326 case $forward in
 327   1)
 328     run iptables -A FORWARD -g poorly-understood \
 329             -d 224.0.0.0/4
 330     run ip6tables -A FORWARD -g poorly-understood \
 331             -d ff::/8
 332     ;;
 333 esac
 334
 335 m4_divert(82)m4_dnl
 336 ###--------------------------------------------------------------------------
 337 ### Check for source routing.
 338
 339 clearchain check-srcroute
 340
 341 run iptables -A check-srcroute -g forbidden \
 342     -m ipv4options --any --flags lsrr,ssrr
 343 run ip6tables -A check-srcroute -g forbidden \
 344     -m rt
 345
 346 for c in INPUT FORWARD; do
 347   for m in $from_scary $from_untrusted; do
 348     run ip46tables -A $c -m mark --mark $m/$MASK_FROM -j check-srcroute
 349   done
 350 done
 351
 352 m4_divert(84)m4_dnl
 353 ###--------------------------------------------------------------------------
 354 ### Locally-bound packet inspection.
 355
 356 clearchain inbound
 357 clearchain inbound-untrusted
 358
 359 ## Track connections.
 360 commonrules inbound
 361 conntrack inbound
 362
 363 ## Allow incoming bootp.  Bootp won't be forwarded, so this is obviously a
 364 ## local request.
 365 run iptables -A inbound -j ACCEPT \
 366         -s 0.0.0.0 -d 255.255.255.255 \
 367         -p udp --source-port $port_bootpc --destination-port $port_bootps
 368 run iptables -A inbound -j ACCEPT \
 369         -s 172.29.198.0/23 \
 370         -p udp --source-port $port_bootpc --destination-port $port_bootps
 371
 372 ## Allow incoming ping.  This is the only ICMP left.
 373 run iptables -A inbound -j ACCEPT -p icmp
 374 run ip6tables -A inbound -j ACCEPT -p icmpv6
 375
 376 m4_divert(88)m4_dnl
 377 ## Allow unusual things.
 378 openports inbound
 379
 380 ## Inspect inbound packets from untrusted sources.
 381 run iptables -A inbound -s 172.29.198.0/24 -g inbound-untrusted
 382 run ip6tables -A inbound -s 2001:8b0:c92:8000::/49 -g inbound-untrusted
 383 run ip46tables -A inbound-untrusted -g forbidden
 384 run ip46tables -A inbound -g forbidden
 385 run ip46tables -A INPUT -m mark --mark $from_scary/$MASK_FROM -g inbound
 386 run ip46tables -A INPUT -m mark --mark $from_untrusted/$MASK_FROM -g inbound
 387
 388 ## Allow responses from the scary outside world into the untrusted net, but
 389 ## don't let untrusted things run services.
 390 case $forward in
 391   1)
 392     run ip46tables -A FORWARD -j ACCEPT \
 393         -m mark --mark $(( $from_scary | $to_untrusted ))/$(( $MASK_FROM | $MASK_TO )) \
 394         -m state --state ESTABLISHED,RELATED
 395     ;;
 396 esac
 397
 398 ## Otherwise process as indicated by the mark.
 399 for i in $inchains; do
 400   run ip46tables -A $i -m mark ! --mark 0/$MASK_MASK -j ACCEPT
 401 done
 402
 403 m4_divert(-1)
 404 ###----- That's all, folks --------------------------------------------------