From patchwork Wed Mar 9 00:30:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 594765 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 1469414031D; Wed, 9 Mar 2016 11:43:27 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1adSDk-0005JK-Bw; Wed, 09 Mar 2016 00:43:24 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1adS7u-0001HX-DE for kernel-team@lists.ubuntu.com; Wed, 09 Mar 2016 00:37:22 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1adS7t-0003xk-UI; Wed, 09 Mar 2016 00:37:22 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1adS7r-00089y-8j; Tue, 08 Mar 2016 16:37:19 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.19.y-ckt 168/196] flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen Date: Tue, 8 Mar 2016 16:30:26 -0800 Message-Id: <1457483454-30115-169-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457483454-30115-1-git-send-email-kamal@canonical.com> References: <1457483454-30115-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Cc: Kamal Mostafa , Alexander Duyck , "David S . Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.19.8-ckt16 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Alexander Duyck [ Upstream commit 461547f3158978c180d74484d58e82be9b8e7357, since we lack the flow dissector flags in this release we guard the flow label access using a test on 'skb' being NULL ] This patch fixes an issue with unaligned accesses when using eth_get_headlen on a page that was DMA aligned instead of being IP aligned. The fact is when trying to check the length we don't need to be looking at the flow label so we can reorder the checks to first check if we are supposed to gather the flow label and then make the call to actually get it. v2: Updated path so that either STOP_AT_FLOW_LABEL or KEY_FLOW_LABEL can cause us to check for the flow label. Reported-by: Sowmini Varadhan Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/core/flow_dissector.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 4508493..e36bd03 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -113,7 +113,6 @@ ip: case htons(ETH_P_IPV6): { const struct ipv6hdr *iph; struct ipv6hdr _iph; - __be32 flow_label; ipv6: iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph); @@ -130,8 +129,9 @@ ipv6: flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr); flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr); - flow_label = ip6_flowlabel(iph); - if (flow_label) { + if (skb && ip6_flowlabel(iph)) { + __be32 flow_label = ip6_flowlabel(iph); + /* Awesome, IPv6 packet has a flow label so we can * use that to represent the ports without any * further dissection.