Hi Pablo, On Fri, Jan 9, 2015 at 5:35 AM, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> wrote: > 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. I already had nf_defrag_ipv6 installed when the issue occured. But I see ip6table_raw_hook returning NF_DROP for the second fragment. Thanks, Rahul -- 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
