From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbdEAVcQ (ORCPT ); Mon, 1 May 2017 17:32:16 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57850 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752299AbdEAVcK (ORCPT ); Mon, 1 May 2017 17:32:10 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , "David S. Miller" Subject: [PATCH 4.9 10/54] l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6 Date: Mon, 1 May 2017 14:31:17 -0700 Message-Id: <20170501212632.190867086@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170501212631.798128131@linuxfoundation.org> References: <20170501212631.798128131@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault [ Upstream commit 94d7ee0baa8b764cf64ad91ed69464c1a6a0066b ] The code following l2tp_tunnel_find() expects that a new reference is held on sk. Either sk_receive_skb() or the discard_put error path will drop a reference from the tunnel's socket. This issue exists in both l2tp_ip and l2tp_ip6. Fixes: a3c18422a4b4 ("l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_ip.c | 5 +++-- net/l2tp/l2tp_ip6.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -178,9 +178,10 @@ pass_up: tunnel_id = ntohl(*(__be32 *) &skb->data[4]); tunnel = l2tp_tunnel_find(net, tunnel_id); - if (tunnel != NULL) + if (tunnel) { sk = tunnel->sock; - else { + sock_hold(sk); + } else { struct iphdr *iph = (struct iphdr *) skb_network_header(skb); read_lock_bh(&l2tp_ip_lock); --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -191,9 +191,10 @@ pass_up: tunnel_id = ntohl(*(__be32 *) &skb->data[4]); tunnel = l2tp_tunnel_find(net, tunnel_id); - if (tunnel != NULL) + if (tunnel) { sk = tunnel->sock; - else { + sock_hold(sk); + } else { struct ipv6hdr *iph = ipv6_hdr(skb); read_lock_bh(&l2tp_ip6_lock);