Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753547AbdFSTI4 (ORCPT + 2 others); Mon, 19 Jun 2017 15:08:56 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:52430 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751761AbdFSSg4 (ORCPT ); Mon, 19 Jun 2017 14:36:56 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: =?latin1?q?Paul=20H=FCber?= , "David S . Miller" , Willy Tarreau Subject: [PATCH 3.10 178/268] l2tp: avoid use-after-free caused by l2tp_ip_backlog_recv Date: Mon, 19 Jun 2017 20:31:17 +0200 Message-Id: <1497897167-14556-179-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1497897167-14556-1-git-send-email-w@1wt.eu> References: <1497897167-14556-1-git-send-email-w@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=latin1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Paul H?ber commit 51fb60eb162ab84c5edf2ae9c63cf0b878e5547e upstream. l2tp_ip_backlog_recv may not return -1 if the packet gets dropped. The return value is passed up to ip_local_deliver_finish, which treats negative values as an IP protocol number for resubmission. Signed-off-by: Paul H?ber Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau --- net/l2tp/l2tp_ip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c index f4d30b5..1f65095 100644 --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -382,7 +382,7 @@ static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb) drop: IP_INC_STATS(sock_net(sk), IPSTATS_MIB_INDISCARDS); kfree_skb(skb); - return -1; + return 0; } /* Userspace will call sendmsg() on the tunnel socket to send L2TP -- 2.8.0.rc2.1.gbe9624a