From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gao feng Subject: Re: [PATCH RESEND] netfilter: bridge: unshare bridge info before change it Date: Wed, 19 Nov 2014 10:11:25 +0800 Message-ID: <546BFC4D.7070203@cn.fujitsu.com> References: <1416203323-22745-1-git-send-email-gaofeng@cn.fujitsu.com> <20141118183419.GA5078@salvia> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Cc: To: Pablo Neira Ayuso Return-path: Received: from cn.fujitsu.com ([59.151.112.132]:25065 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753650AbaKSCLa (ORCPT ); Tue, 18 Nov 2014 21:11:30 -0500 In-Reply-To: <20141118183419.GA5078@salvia> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On 11/19/2014 02:34 AM, Pablo Neira Ayuso wrote: > On Mon, Nov 17, 2014 at 01:48:43PM +0800, Gao feng wrote: >> diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c >> index 1a4f32c..b4612b9 100644 >> --- a/net/bridge/br_netfilter.c >> +++ b/net/bridge/br_netfilter.c >> @@ -653,7 +643,11 @@ static int br_nf_forward_finish(struct sk_buff *skb) >> in = nf_bridge->physindev; >> if (nf_bridge->mask & BRNF_PKT_TYPE) { >> skb->pkt_type = PACKET_OTHERHOST; >> - nf_bridge->mask ^= BRNF_PKT_TYPE; >> + >> + if (!nf_bridge_unset_mask(skb, BRNF_PKT_TYPE)) { >> + kfree_skb(skb); >> + return 0; >> + } > > This can now release the packet and, thus, drop it. > > However, br_nf_forward_ip() always returns NF_STOLEN. > > Could you revisit the error paths and confirm they are correct? Since br_nf_forward_ip() returns NF_STOLEN, br_nf_forward_finish should make sure this skb will be released. if unser_mask for this skb is failed, we free it. if unset successed, the hooks on NF_BR_FORWARD or br_forward_finish will free this skb. I check the error paths again, find a missing null check of nf_bridge. I will post v2 patch.