From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 5/8] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len Date: Sat, 5 Apr 2014 18:03:47 +0200 Message-ID: <1396713830-4009-6-git-send-email-pablo@netfilter.org> References: <1396713830-4009-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:34340 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753015AbaDEQED (ORCPT ); Sat, 5 Apr 2014 12:04:03 -0400 In-Reply-To: <1396713830-4009-1-git-send-email-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Andrey Vagin "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. The right way to fix this problem is reducing the size of the ecache extension (4) and Florian is going to do this, but these changes will be quite large to be appropriate for a stable tree. Fixes: 5b423f6a40a0 (netfilter: nf_conntrack: fix racy timer handling with reliable) Cc: Pablo Neira Ayuso Cc: Patrick McHardy Cc: Jozsef Kadlecsik Cc: "David S. Miller" Signed-off-by: Andrey Vagin Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_extend.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h index 956b175..55d1504 100644 --- a/include/net/netfilter/nf_conntrack_extend.h +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -47,8 +47,8 @@ enum nf_ct_ext_id { /* Extensions: optional stuff which isn't permanently in struct. */ struct nf_ct_ext { struct rcu_head rcu; - u8 offset[NF_CT_EXT_NUM]; - u8 len; + u16 offset[NF_CT_EXT_NUM]; + u16 len; char data[0]; }; -- 1.7.10.4