From patchwork Tue Oct 30 00:35:15 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cong Wang X-Patchwork-Id: 990629 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="B84VZ0NZ"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42kXFw6WKQz9s2P for ; Tue, 30 Oct 2018 11:21:40 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725911AbeJ3JMo (ORCPT ); Tue, 30 Oct 2018 05:12:44 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:36738 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725840AbeJ3JMo (ORCPT ); Tue, 30 Oct 2018 05:12:44 -0400 Received: by mail-pg1-f194.google.com with SMTP id z17-v6so4714386pgv.3 for ; Mon, 29 Oct 2018 17:21:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=NVeX0UCCsQspC3x10yXmlRJtr6qCbYizDzgdUKfAvyE=; b=B84VZ0NZI3rzWDH8z15UvgTmdpKEUXA2aUlD2YMwRjx6HReAd32neVh5+PxwyYzYpd 0NrnJr/ZyAibDtLNalfDaDs8cu/dW9kpknlkp4S5hR9sIzZ7gtU+2ChnvESZenAchBC7 WNmd/v7TXo4oyDgPXdTIQx2vwXNIdVXcNNZcrOypgqQTVY87B+xm4jZqf94YU5jkmYlP T68OsnRytuNmKLPAzn2bmVcqS2kMlTQVzk61bB1zRbDHKi9W5QuLMgUF4SaqzBNpb3bZ ukvFInGoMXVhxiQLSPECffdWlmTT1k0cmWY6uQuaqS4ZgUIN9E9kQs6ky/tBiT+XICru qd1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=NVeX0UCCsQspC3x10yXmlRJtr6qCbYizDzgdUKfAvyE=; b=XuTdyAmPsaJ4/0QAzKyG0TNfIUq35jYHJFOfmTu91+5BlsvxrGTPbeugznb4+u//gs nr7atO2we338Xqb6iN+QqnVE8VXei6JJpNvjDOHi5R4Ly9HhNx0Mpvgxb4Z83ktDJlU7 iLbS1qn0CAC6mB6iOfTyk82VtOaVqKyzmp0LigQE22rUl2zznc7VrKKMwEg68preu4u5 tZ/2hVl9CECVpnaYBHy5vsstGCLwsO+hspooU6yyCo1QqE/njFnkWMJ/pJGz/ViUm1Dg GWRsa72GjHHJpT4NCS4IswJ6aD+Y50snOiOAl36F6wWpuZZ+UQ1GrEyOwSfbAIPNgS3E vmbA== X-Gm-Message-State: AGRZ1gL+eUqPTzTSj9h42L2P9pXBBDLnRA8nSHCX/+7ea0N/984bIMsI HNx5Bcb1vtJT+sqLA0dUN5KNXuS2 X-Google-Smtp-Source: AJdET5f+inGiyXr8LYrv7BUZrgsCgBWxo/lK8lDt/eyhgREZKwDiP3qZg0Y03QFaA9J0qLw+sD+ONw== X-Received: by 2002:a62:5547:: with SMTP id j68-v6mr602598pfb.166.1540858896421; Mon, 29 Oct 2018 17:21:36 -0700 (PDT) Received: from linux-6brj.site (c-24-5-243-68.hsd1.ca.comcast.net. [24.5.243.68]) by smtp.gmail.com with ESMTPSA id u7-v6sm23875744pfl.34.2018.10.29.17.21.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Oct 2018 17:21:35 -0700 (PDT) From: Cong Wang To: netdev@vger.kernel.org Cc: Cong Wang , Eric Dumazet Subject: [Patch net] net: make pskb_trim_rcsum_slow() robust Date: Mon, 29 Oct 2018 17:35:15 -0700 Message-Id: <20181030003515.12075-1-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 2.16.4 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Most callers of pskb_trim_rcsum() simply drops the skb when it fails, however, ip_check_defrag() still continues to pass the skb up to stack. In that case, we should restore its previous csum if __pskb_trim() fails. Found this during code review. Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends") Cc: Eric Dumazet Signed-off-by: Cong Wang --- net/core/skbuff.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 946de0e24c87..5decd6e6d2b6 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1843,6 +1843,9 @@ EXPORT_SYMBOL(___pskb_trim); */ int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) { + __wsum old_csum = skb->csum; + int ret; + if (skb->ip_summed == CHECKSUM_COMPLETE) { int delta = skb->len - len; @@ -1850,7 +1853,10 @@ int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) skb_checksum(skb, len, delta, 0), len); } - return __pskb_trim(skb, len); + ret = __pskb_trim(skb, len); + if (unlikely(ret)) + skb->csum = old_csum; + return ret; } EXPORT_SYMBOL(pskb_trim_rcsum_slow);