"len" contains sizeof(nf_ct_ext) and size of extensions. In a worst case it can contain all extensions. Bellow you can find sizes for all types of extensions. Their sum is definitely bigger than 256. nf_ct_ext_types[0]->len = 24 nf_ct_ext_types[1]->len = 32 nf_ct_ext_types[2]->len = 24 nf_ct_ext_types[3]->len = 32 nf_ct_ext_types[4]->len = 152 nf_ct_ext_types[5]->len = 2 nf_ct_ext_types[6]->len = 16 nf_ct_ext_types[7]->len = 8 I have seen "len" up to 280 and my host has crashes w/o this patch. Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Cc: Patrick McHardy <kaber@xxxxxxxxx> Cc: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx> --- include/net/netfilter/nf_conntrack_extend.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index 956b175..36fd6bf 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -48,7 +48,7 @@ enum nf_ct_ext_id { struct nf_ct_ext { struct rcu_head rcu; u8 offset[NF_CT_EXT_NUM]; - u8 len; + u16 len; char data[0]; }; -- 1.8.5.3 -- 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