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=-4.0 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 0BF11C43219 for ; Sat, 27 Apr 2019 15:20:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB392206A3 for ; Sat, 27 Apr 2019 15:20:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728173AbfD0PUx (ORCPT ); Sat, 27 Apr 2019 11:20:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33962 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727591AbfD0PPe (ORCPT ); Sat, 27 Apr 2019 11:15:34 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hKP35-0000zO-Ka; Sat, 27 Apr 2019 16:15:31 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hKP2j-0004UJ-RU; Sat, 27 Apr 2019 16:15:09 +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, Denis Kirjanov , "Jacob Wen" , "Guillaume Nault" , "David S. Miller" Date: Sat, 27 Apr 2019 16:13:09 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 080/202] l2tp: copy 4 more bytes to linear part if necessary In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 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 3.16.66-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jacob Wen commit 91c524708de6207f59dd3512518d8a1c7b434ee3 upstream. The size of L2TPv2 header with all optional fields is 14 bytes. l2tp_udp_recv_core only moves 10 bytes to the linear part of a skb. This may lead to l2tp_recv_common read data outside of a skb. This patch make sure that there is at least 14 bytes in the linear part of a skb to meet the maximum need of l2tp_udp_recv_core and l2tp_recv_common. The minimum size of both PPP HDLC-like frame and Ethernet frame is larger than 14 bytes, so we are safe to do so. Also remove L2TP_HDR_SIZE_NOSEQ, it is unused now. Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Suggested-by: Guillaume Nault Signed-off-by: Jacob Wen Acked-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -82,8 +82,7 @@ #define L2TP_SLFLAG_S 0x40000000 #define L2TP_SL_SEQ_MASK 0x00ffffff -#define L2TP_HDR_SIZE_SEQ 10 -#define L2TP_HDR_SIZE_NOSEQ 6 +#define L2TP_HDR_SIZE_MAX 14 /* Default trace flags */ #define L2TP_DEFAULT_DEBUG_FLAGS 0 @@ -897,7 +896,7 @@ static int l2tp_udp_recv_core(struct l2t __skb_pull(skb, sizeof(struct udphdr)); /* Short packet? */ - if (!pskb_may_pull(skb, L2TP_HDR_SIZE_SEQ)) { + if (!pskb_may_pull(skb, L2TP_HDR_SIZE_MAX)) { l2tp_info(tunnel, L2TP_MSG_DATA, "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);