From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 164B5C169C4 for ; Tue, 29 Jan 2019 11:51:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB3922086C for ; Tue, 29 Jan 2019 11:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548762679; bh=K2j4/7t7OcYdQBRy6HtcnXkwGHHpzT54WmQpkhn/E50=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VWEERH5MsNtJsQxQR6N4hnY1dHNeui6FQw5ZE612hV7DKY+EprktF3iPBorPb/i8J 0mkaJMdbIMUcQsDH/gFAyrWYx7/pPmjvN6yROl/Gg1BUgj+rCC224BFmlmQPusnItz gLxcTQQjCMfA0NADpMotGWA2PxOPy1OoqsdA0b68= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731847AbfA2LvS (ORCPT ); Tue, 29 Jan 2019 06:51:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:42742 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731366AbfA2LvP (ORCPT ); Tue, 29 Jan 2019 06:51:15 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8FC0820882; Tue, 29 Jan 2019 11:51:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548762675; bh=K2j4/7t7OcYdQBRy6HtcnXkwGHHpzT54WmQpkhn/E50=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uGG3qsXlGq05lkRyvb5gYMvfRJkER48XzLxp2cPbOTlhqBEWHf3gO1U0n/AuZbe0U Od1+K6u+6NczHb6pdzb3gDkB0ke8jFG0F5IKCzz1fCZ8WcUnx8VaUstI5hWoCz27JL F2MJ7vvuHvhTk5Iv9SiHrrKg0lsrTSBFgEsWcsNE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Olsson , Jamal Hadi Salim , Jiri Pirko , Cong Wang , "David S. Miller" Subject: [PATCH 4.9 06/44] net_sched: refetch skb protocol for each filter Date: Tue, 29 Jan 2019 12:36:01 +0100 Message-Id: <20190129113140.567750587@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190129113139.826927690@linuxfoundation.org> References: <20190129113139.826927690@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang [ Upstream commit cd0c4e70fc0ccfa705cdf55efb27519ce9337a26 ] Martin reported a set of filters don't work after changing from reclassify to continue. Looking into the code, it looks like skb protocol is not always fetched for each iteration of the filters. But, as demonstrated by Martin, TC actions could modify skb->protocol, for example act_vlan, this means we have to refetch skb protocol in each iteration, rather than using the one we fetch in the beginning of the loop. This bug is _not_ introduced by commit 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}"), technically, if act_vlan is the only action that modifies skb protocol, then it is commit c7e2b9689ef8 ("sched: introduce vlan action") which introduced this bug. Reported-by: Martin Olsson Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_api.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1850,7 +1850,6 @@ done: int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp, struct tcf_result *res, bool compat_mode) { - __be16 protocol = tc_skb_protocol(skb); #ifdef CONFIG_NET_CLS_ACT const struct tcf_proto *old_tp = tp; int limit = 0; @@ -1858,6 +1857,7 @@ int tc_classify(struct sk_buff *skb, con reclassify: #endif for (; tp; tp = rcu_dereference_bh(tp->next)) { + __be16 protocol = tc_skb_protocol(skb); int err; if (tp->protocol != protocol && @@ -1884,7 +1884,6 @@ reset: } tp = old_tp; - protocol = tc_skb_protocol(skb); goto reclassify; #endif }