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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 47F98C7112A for ; Sun, 14 Oct 2018 15:55:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B19020645 for ; Sun, 14 Oct 2018 15:55:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B19020645 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729435AbeJNXgY (ORCPT ); Sun, 14 Oct 2018 19:36:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36036 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727712AbeJNXLz (ORCPT ); Sun, 14 Oct 2018 19:11:55 -0400 Received: from [2a02:8011:400e:2:cbab:f00:c93f:614] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1gBiLh-0004cg-Qr; Sun, 14 Oct 2018 16:30:34 +0100 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gBiLa-0000ih-7o; Sun, 14 Oct 2018 16:30:26 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Eric Dumazet" , "David S. Miller" , "Willem de Bruijn" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 331/366] net: test tailroom before appending to linear skb In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:cbab:f00:c93f:614 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn commit 113f99c3358564a0647d444c2ae34e8b1abfd5b9 upstream. Device features may change during transmission. In particular with corking, a device may toggle scatter-gather in between allocating and writing to an skb. Do not unconditionally assume that !NETIF_F_SG at write time implies that the same held at alloc time and thus the skb has sufficient tailroom. This issue predates git history. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Eric Dumazet Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/ipv4/ip_output.c | 3 ++- net/ipv6/ip6_output.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1025,7 +1025,8 @@ alloc_new_skb: if (copy > length) copy = length; - if (!(rt->dst.dev->features&NETIF_F_SG)) { + if (!(rt->dst.dev->features&NETIF_F_SG) && + skb_tailroom(skb) >= copy) { unsigned int off; off = skb->len; --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1453,7 +1453,8 @@ alloc_new_skb: if (copy > length) copy = length; - if (!(rt->dst.dev->features&NETIF_F_SG)) { + if (!(rt->dst.dev->features&NETIF_F_SG) && + skb_tailroom(skb) >= copy) { unsigned int off; off = skb->len;