numbers.m4, gibson.m4: Allow gibson public SIP access.

[firewall] / local.m4

diff --git a/local.m4 b/local.m4
index 4123a77..2d880b9 100644 (file)
--- a/local.m4
+++ b/local.m4
@@ -38,6 +38,14 @@ m4_divert(-1)m4_dnl
 m4_divert(46)m4_dnl
 ## Networks and routing.
 
+defiface $if_dmz \
+       trusted:62.49.204.144/28 \
+       trusted:172.29.199.0/25 \
+       untrusted:default
+defiface $if_trusted \
+       trusted:172.29.199.0/25 \
+       untrusted:default
+defiface $if_safe safe:172.29.199.192/26
 defiface $if_untrusted \
        untrusted:172.29.198.0/25
 defvpn $if_vpn safe 172.29.199.128/27 \
@@ -46,10 +54,6 @@ defvpn $if_vpn safe 172.29.199.128/27 \
 defiface $if_iodine untrusted:172.29.198.128/28
 defiface $if_its_mz safe:172.29.199.160/30
 defiface $if_its_pi safe:192.168.0.0/24
-defiface $if_trusted \
-       trusted:172.29.199.0/26 \
-       safe:172.29.199.64/27 \
-       untrusted:default
 
 ## Default NTP servers.
 ntp_servers="158.152.1.76 158.152.1.204 194.159.253.2 195.173.57.232"
@@ -58,39 +62,45 @@ m4_divert(60)m4_dnl
 ###--------------------------------------------------------------------------
 ### Special forwarding exemptions.
 
+## Only allow these packets if they're not fragmented.  (Don't trust safe
+## hosts's fragment reassembly to be robust against malicious fragments.)
+## There's a hideous bug in iptables 1.4.11.1 which botches the meaning of
+## `! -f', so we do the negation using early return from a subchain.
+clearchain fwd-spec-nofrag
+run iptables -A fwd-spec-nofrag -j RETURN --fragment
+run ip6tables -A fwd-spec-nofrag -j RETURN \
+       -m ipv6header --soft --header frag
+run iptables -A FORWARD -j fwd-spec-nofrag
+
 ## Allow ping from safe/noloop to untrusted networks.
-run iptables -A FORWARD -j ACCEPT \
-       -p icmp ! -f --icmp-type echo-request \
+run iptables -A fwd-spec-nofrag -j ACCEPT \
+       -p icmp --icmp-type echo-request \
        -m mark --mark $to_untrusted/$MASK_TO
-run iptables -A FORWARD -j ACCEPT \
-       -p icmp ! -f --icmp-type echo-reply \
+run iptables -A fwd-spec-nofrag -j ACCEPT \
+       -p icmp --icmp-type echo-reply \
        -m mark --mark $from_untrusted/$MASK_FROM \
        -m state --state ESTABLISHED
-run ip6tables -A FORWARD -j ACCEPT \
+run ip6tables -A fwd-spec-nofrag -j ACCEPT \
        -p ipv6-icmp --icmpv6-type echo-request \
-       -m ipv6header --soft ! --header frag \
        -m mark --mark $to_untrusted/$MASK_TO
-run ip6tables -A FORWARD -j ACCEPT \
+run ip6tables -A fwd-spec-nofrag -j ACCEPT \
        -p ipv6-icmp --icmpv6-type echo-reply \
-       -m ipv6header --soft ! --header frag \
        -m mark --mark $from_untrusted/$MASK_FROM \
        -m state --state ESTABLISHED
 
 ## Allow SSH from safe/noloop to untrusted networks.
-run iptables -A FORWARD -j ACCEPT \
-       -p tcp ! -f --destination-port $port_ssh \
+run iptables -A fwd-spec-nofrag -j ACCEPT \
+       -p tcp --destination-port $port_ssh \
        -m mark --mark $to_untrusted/$MASK_TO
-run iptables -A FORWARD -j ACCEPT \
-       -p tcp ! -f --source-port $port_ssh \
+run iptables -A fwd-spec-nofrag -j ACCEPT \
+       -p tcp --source-port $port_ssh \
        -m mark --mark $from_untrusted/$MASK_FROM \
        -m state --state ESTABLISHED
-run ip6tables -A FORWARD -j ACCEPT \
+run ip6tables -A fwd-spec-nofrag -j ACCEPT \
        -p tcp --destination-port $port_ssh \
-       -m ipv6header --soft ! --header frag \
        -m mark --mark $to_untrusted/$MASK_TO
-run ip6tables -A FORWARD -j ACCEPT \
+run ip6tables -A fwd-spec-nofrag -j ACCEPT \
        -p tcp --source-port $port_ssh \
-       -m ipv6header --soft ! --header frag \
        -m mark --mark $from_untrusted/$MASK_FROM \
        -m state --state ESTABLISHED
 
@@ -128,12 +138,21 @@ run iptables -A inbound -j ACCEPT \
        -s 172.29.198.0/23 \
        -p udp --source-port $port_bootpc --destination-port $port_bootps
 
-## Incoming broadcast multicast on a network interface associated with the
-## trusted network is OK, since it must have originated there (or been
-## forwarded, but we don't do that yet).
-run iptables -A inbound -j ACCEPT \
+## Incoming multicast on a network interface associated with a trusted
+## network is OK, since it must have originated there (or been forwarded, but
+## we don't do that yet).
+for i in $(echo $if_trusted $if_dmz $if_safe | sed 'y/,/ /'); do
+  echo $i
+done | {
+  seen=:
+  while read i; do
+    case "$seen" in *:$i:*) continue ;; esac
+    seen=$seen$i:
+    run iptables -A inbound -j ACCEPT \
        -s 0.0.0.0 -d 224.0.0.0/24 \
-       -i $if_trusted
+       -i $i
+  done
+}
 
 ## Allow incoming ping.  This is the only ICMP left.
 run ip46tables -A inbound -j ACCEPT -p icmp