From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933535AbcGGBWB (ORCPT ); Wed, 6 Jul 2016 21:22:01 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50278 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933425AbcGGBU2 (ORCPT ); Wed, 6 Jul 2016 21:20:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , WANG Cong , Jamal Hadi Salim , Stephen Hemminger , "David S. Miller" Subject: [PATCH 4.4 05/32] netem: fix a use after free Date: Wed, 6 Jul 2016 18:19:15 -0700 Message-Id: <20160707011626.702862240@linuxfoundation.org> X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160707011626.475554429@linuxfoundation.org> References: <20160707011626.475554429@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 21de12ee5568fd1aec47890c72967abf791ac80a ] If the packet was dropped by lower qdisc, then we must not access it later. Save qdisc_pkt_len(skb) in a temp variable. Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too") Signed-off-by: Eric Dumazet Cc: WANG Cong Cc: Jamal Hadi Salim Cc: Stephen Hemminger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_netem.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -650,14 +650,14 @@ deliver: #endif if (q->qdisc) { + unsigned int pkt_len = qdisc_pkt_len(skb); int err = qdisc_enqueue(skb, q->qdisc); - if (unlikely(err != NET_XMIT_SUCCESS)) { - if (net_xmit_drop_count(err)) { - qdisc_qstats_drop(sch); - qdisc_tree_reduce_backlog(sch, 1, - qdisc_pkt_len(skb)); - } + if (err != NET_XMIT_SUCCESS && + net_xmit_drop_count(err)) { + qdisc_qstats_drop(sch); + qdisc_tree_reduce_backlog(sch, 1, + pkt_len); } goto tfifo_dequeue; }