Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752542AbcDVLUt (ORCPT ); Fri, 22 Apr 2016 07:20:49 -0400 Received: from mx2.suse.de ([195.135.220.15]:43943 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483AbcDVLGS (ORCPT ); Fri, 22 Apr 2016 07:06:18 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Haishuang Yan , "David S . Miller" , Jiri Slaby Subject: [PATCH 3.12 34/78] ipv4: l2tp: fix a potential issue in l2tp_ip_recv Date: Fri, 22 Apr 2016 13:05:17 +0200 Message-Id: <4a05fe250a8195d5568d91e926b0800eca9e35f2.1461323133.git.jslaby@suse.cz> X-Mailer: git-send-email 2.8.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 49 From: Haishuang Yan 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit 5745b8232e942abd5e16e85fa9b27cc21324acf0 ] pskb_may_pull() can change skb->data, so we have to load ptr/optr at the right place. Signed-off-by: Haishuang Yan Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- net/l2tp/l2tp_ip.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index da1a1cee1a08..07f8b97f9ae9 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -123,12 +123,11 @@ static int l2tp_ip_recv(struct sk_buff *skb) struct l2tp_tunnel *tunnel = NULL; int length; - /* Point to L2TP header */ - optr = ptr = skb->data; - if (!pskb_may_pull(skb, 4)) goto discard; + /* Point to L2TP header */ + optr = ptr = skb->data; session_id = ntohl(*((__be32 *) ptr)); ptr += 4; @@ -156,6 +155,9 @@ static int l2tp_ip_recv(struct sk_buff *skb) if (!pskb_may_pull(skb, length)) goto discard; + /* Point to L2TP header */ + optr = ptr = skb->data; + ptr += 4; pr_debug("%s: ip recv\n", tunnel->name); print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length); } -- 2.8.1