From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len Date: Thu, 27 Mar 2014 15:45:05 +0000 Message-ID: <20140327154504.GC31944@macbook.localnet> References: <1395934354-13226-1-git-send-email-avagin@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, vvs@parallels.com, Pablo Neira Ayuso , Jozsef Kadlecsik , "David S. Miller" To: Andrey Vagin Return-path: Content-Disposition: inline In-Reply-To: <1395934354-13226-1-git-send-email-avagin@openvz.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Thu, Mar 27, 2014 at 07:32:34PM +0400, Andrey Vagin wrote: > "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. Very nice catch. I suppose we also need to either increase the size of offset[] or rearrange the extension so 4 (ECACHE) comes last. > > Cc: Pablo Neira Ayuso > Cc: Patrick McHardy > Cc: Jozsef Kadlecsik > Cc: "David S. Miller" > Signed-off-by: Andrey Vagin > --- > 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@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html