X-Git-Url: https://git.distorted.org.uk/~mdw/firewall/blobdiff_plain/e34a93c12d431953e694db44ef9df0bb79687726..HEAD:/classify.m4

diff --git a/classify.m4 b/classify.m4
index 5b6f209..98b9795 100644
--- a/classify.m4
+++ b/classify.m4
@@ -45,8 +45,9 @@ m4_divert(40)m4_dnl
 ###
 ### The mangle chains are arranged as follows.
 ###
-### The PREROUTING hook simply invokes in-classify and out-classify chains as
-### subroutines.  These will tail-call appropriate classification chains.
+### The INPUT and FORWARD hooks simply invoke in-classify and out-classify
+### chains as subroutines.  These will tail-call appropriate classification
+### chains.
 ###
 ### The in-classify chain is responsible for both source address
 ### classification and verifying that the packet arrived from the correct
@@ -56,11 +57,12 @@ m4_divert(40)m4_dnl
 ### goes to bad-source-address, which logs a message and drops the packet.
 ### The default interface is special.  If no explicit matches are found, it
 ### dispatches to in-default which forbids a few obviously evil things and
-### finally dispatches to mark-from-untrusted.
+### finally dispatches to mark-from-DEFAULT (usually `untrusted').
 ###
 ### The out-classify is simpler because it doesn't care about the interface.
 ### It simply checks each network range in turn, dispatching to mark-to-CLASS
-### on a match or mark-to-DEFAULT (probably untrusted) if there is no match.
+### on a match or mark-to-DEFAULT (probably `untrusted') if there is no
+### match.
 
 clearchain mangle:in-classify mangle:in-default mangle:out-classify
 clearchain mangle:local-source
@@ -94,7 +96,7 @@ run iptables -t mangle -A in-classify -j RETURN \
 ## over the loopback interface, I shouldn't see a packet from me over any
 ## other interface.  Except that I will if I sent a broadcast or multicast.
 ## Allow the broadcasts, and remember not to trust them.  There are no
-## broadcast addresses in IPv6 (only link-local multicast)m so we don't have
+## broadcast addresses in IPv6 (only link-local multicast) so we don't have
 ## to worry about that.
 run iptables -t mangle -A local-source -j RETURN \
 	-m addrtype --dst-type BROADCAST
@@ -129,7 +131,7 @@ run iptables -t mangle -A in-classify -g bad-source-address \
 run iptables -t mangle -A in-classify -g bad-source-address \
 	-m addrtype --src-type BROADCAST \
 
-## Special IPv6 addresses.  Format multicast sources, and mark zero and
+## Special IPv6 addresses.  Forbid multicast sources, and mark zero and
 ## link local addresses.
 for i in :: fe80::/10; do
   run ip6tables -t mangle -A in-classify -g mark-from-link -s $i
@@ -144,6 +146,7 @@ for i in 0.0.0.0 240.0.0.0/4; do
   run iptables -t mangle -A out-classify -g bad-destination-address -d $i
 done
 run iptables -t mangle -A out-classify -g mark-to-link -d 169.254.0.0/16
+run iptables -t mangle -A out-classify -g mark-to-link -d 255.255.255.255
 run iptables -t mangle -A out-classify -g mark-to-link \
 	-m addrtype --dst-type BROADCAST
 
@@ -319,7 +322,8 @@ for entry in $ifmap; do
 done
 
 ## Fill in the black holes in the network.  Some of these might actually be
-## known networks, so don't fill those in again.
+## known networks, so don't fill those in again.  See RFC5735 and RFC4291,
+## and their successors.
 for addr in \
 	10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 \
 	127.0.0.0/8 \
@@ -329,7 +333,8 @@ do
   run iptables -t mangle -A in-default -s $addr -g bad-source-address
 done
 for addr in \
-	fc00::/7 \
+	fc00::/7 fec0::/10 \
+	::0:0/96 ::ffff:0:0/96 \
 	2001:db8::/32
 do
   case $alladdrs in *!$addr!*) continue ;; esac
@@ -339,12 +344,16 @@ run ip46tables -t mangle -A in-default -g mark-from-$net_class_default
 
 m4_divert(92)m4_dnl
 ## Put the final default decision on the in-default chain, and attach the
-## classification chains to the PREROUTING hook.
+## classification chains to the INPUT and (maybe) FORWARD hooks.
 for iface in $defaultifaces; do
   run ip46tables -t mangle -A in-$iface -g in-default
 done
-run ip46tables -t mangle -A PREROUTING -j in-classify
-run ip46tables -t mangle -A PREROUTING -j out-classify
+chains="INPUT"
+case $forward in 1) chains="$chains FORWARD" ;; esac
+for c in $chains; do
+  run ip46tables -t mangle -A $c -j in-classify
+  run ip46tables -t mangle -A $c -j out-classify
+done
 
 ## Incoming stuff to or from a link-local address is OK.
 run ip46tables -t mangle -A INPUT \