Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757689AbdLVIxl (ORCPT ); Fri, 22 Dec 2017 03:53:41 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34754 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757621AbdLVIxg (ORCPT ); Fri, 22 Dec 2017 03:53:36 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 017/104] sch_dsmark: fix invalid skb_cow() usage Date: Fri, 22 Dec 2017 09:45:43 +0100 Message-Id: <20171222084610.788252470@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084609.262099650@linuxfoundation.org> References: <20171222084609.262099650@linuxfoundation.org> User-Agent: quilt/0.65 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 Content-Length: 1702 Lines: 53 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit aea92fb2e09e29653b023d4254ac9fbf94221538 ] skb_cow(skb, sizeof(ip header)) is not very helpful in this context. First we need to use pskb_may_pull() to make sure the ip header is in skb linear part, then use skb_try_make_writable() to address clones issues. Fixes: 4c30719f4f55 ("[PKT_SCHED] dsmark: handle cloned and non-linear skb's") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_dsmark.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/net/sched/sch_dsmark.c +++ b/net/sched/sch_dsmark.c @@ -200,9 +200,13 @@ static int dsmark_enqueue(struct sk_buff pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p); if (p->set_tc_index) { + int wlen = skb_network_offset(skb); + switch (tc_skb_protocol(skb)) { case htons(ETH_P_IP): - if (skb_cow_head(skb, sizeof(struct iphdr))) + wlen += sizeof(struct iphdr); + if (!pskb_may_pull(skb, wlen) || + skb_try_make_writable(skb, wlen)) goto drop; skb->tc_index = ipv4_get_dsfield(ip_hdr(skb)) @@ -210,7 +214,9 @@ static int dsmark_enqueue(struct sk_buff break; case htons(ETH_P_IPV6): - if (skb_cow_head(skb, sizeof(struct ipv6hdr))) + wlen += sizeof(struct ipv6hdr); + if (!pskb_may_pull(skb, wlen) || + skb_try_make_writable(skb, wlen)) goto drop; skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))