On Thu, Jan 08, 2015 at 11:39:16PM +0100, Hannes Frederic Sowa wrote: > Hi Pablo, > > On Thu, Jan 8, 2015, at 21:53, Pablo Neira Ayuso wrote: > > I'm afraid we cannot just get rid of that !ipv6_ext_hdr() check. The > > ipv6_find_hdr() function is designed to return the transport protocol. > > After the proposed change, it will return extension header numbers. > > This will break existing ip6tables rulesets since the `-p' option > > relies on this function to match the transport protocol. > > > > Note that the AH header is skipped (see code a bit below this > > problematic fragmentation handling) so the follow up header after the > > AH header is returned as the transport header. > > > > We can probably return the AH protocol number for non-1st fragments. > > However, that would be something new to ip6tables since nobody has > > ever seen packet matching `-p ah' rules. Thus, we restore control to > > the user to allow this, but we would accept all kind of fragmented AH > > traffic through the firewall since we cannot know what transport > > protocol contains from non-1st fragments (unless I'm missing anything, > > I need to have a closer look at this again tomorrow with fresher > > mind). > > The code in question is guarded by (_frag_off != 0), so we are > definitely processing a non-1st fragment currently. The -p match would > happen at the time when the packet is reassembled and thus ipv6_find_hdr > will find the real transport (final) header at this point (I hope I > followed the code correctly here). Then, Rahul should get things working by modprobing nf_defrag_ipv6. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
