Jiri Pirko <jiri@xxxxxxxxxxx> wrote: > Currently, when ipv6 fragment goes through the netfilter, match > functions are called on them directly. This might cause match function > to fail. So benefit from the fact that nf_defrag_ipv6 constructs > reassembled skb for us and use this reassembled skb for matching. > > This patch fixes for example following situation: > On HOSTA do: > ip6tables -I INPUT -p icmpv6 -j DROP > ip6tables -I INPUT -p icmpv6 -m icmp6 --icmpv6-type 128 -j ACCEPT > > and on HOSTB you do: > ping6 HOSTA -s2000 (MTU is 1500) > > Incoming echo requests will be filtered out on HOSTA. This issue does > not occur with smaller packets than MTU (where fragmentation does not happen). [..] > diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c > index 44400c2..5421beb0 100644 > --- a/net/ipv6/netfilter/ip6_tables.c > +++ b/net/ipv6/netfilter/ip6_tables.c > @@ -328,6 +328,7 @@ ip6t_do_table(struct sk_buff *skb, > const struct xt_table_info *private; > struct xt_action_param acpar; > unsigned int addend; > + struct sk_buff *reasm = skb->nfct_reasm ? skb->nfct_reasm : skb; > > /* Initialization */ > indev = in ? in->name : nulldevname; > @@ -363,7 +364,7 @@ ip6t_do_table(struct sk_buff *skb, > > IP_NF_ASSERT(e); > acpar.thoff = 0; > - if (!ip6_packet_match(skb, indev, outdev, &e->ipv6, > + if (!ip6_packet_match(reasm, indev, outdev, &e->ipv6, > &acpar.thoff, &acpar.fragoff, &acpar.hotdrop)) { [..] This is a bit backwards, I think. - We gather frags - Then we invoke ip6t_do_table for each individual fragment So basically your patch is equivalent to for_each_frag( ) ip6t_do_table(reassembled_skb) Which makes no sense to me - why traverse the ruleset n times with the same packet? -- 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