From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932440Ab0LHBCW (ORCPT ); Tue, 7 Dec 2010 20:02:22 -0500 Received: from kroah.org ([198.145.64.141]:33416 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932345Ab0LHBCO (ORCPT ); Tue, 7 Dec 2010 20:02:14 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:57:38 2010 Message-Id: <20101208005738.371418861@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 16:59:06 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Paris , Patrick McHardy Subject: [169/289] netfilter: NF_HOOK_COND has wrong conditional In-Reply-To: <20101208005821.GA2922@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Eric Paris commit ac5aa2e3332ec04889074afdbd1479424d0227a5 upstream. The NF_HOOK_COND returns 0 when it shouldn't due to what I believe to be an error in the code as the order of operations is not what was intended. C will evalutate == before =. Which means ret is getting set to the bool result, rather than the return value of the function call. The code says if (ret = function() == 1) when it meant to say: if ((ret = function()) == 1) Normally the compiler would warn, but it doesn't notice it because its a actually complex conditional and so the wrong code is wrapped in an explict set of () [exactly what the compiler wants you to do if this was intentional]. Fixing this means that errors when netfilter denies a packet get propagated back up the stack rather than lost. Problem introduced by commit 2249065f (netfilter: get rid of the grossness in netfilter.h). Signed-off-by: Eric Paris Signed-off-by: Patrick McHardy Signed-off-by: Greg Kroah-Hartman --- include/linux/netfilter.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -215,7 +215,7 @@ NF_HOOK_COND(uint8_t pf, unsigned int ho int ret; if (!cond || - (ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN) == 1)) + ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) ret = okfn(skb); return ret; }