From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbdEAVqb (ORCPT ); Mon, 1 May 2017 17:46:31 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58338 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbdEAVfl (ORCPT ); Mon, 1 May 2017 17:35:41 -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 4.10 11/62] l2tp: purge socket queues in the .destruct() callback Date: Mon, 1 May 2017 14:34:24 -0700 Message-Id: <20170501212731.224015090@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170501212730.774855694@linuxfoundation.org> References: <20170501212730.774855694@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 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault [ Upstream commit e91793bb615cf6cdd59c0b6749fe173687bb0947 ] The Rx path may grab the socket right before pppol2tp_release(), but nothing guarantees that it will enqueue packets before skb_queue_purge(). Therefore, the socket can be destroyed without its queues fully purged. Fix this by purging queues in pppol2tp_session_destruct() where we're guaranteed nothing is still referencing the socket. Fixes: 9e9cb6221aa7 ("l2tp: fix userspace reception on plain L2TP sockets") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_ppp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -450,6 +450,10 @@ static void pppol2tp_session_close(struc static void pppol2tp_session_destruct(struct sock *sk) { struct l2tp_session *session = sk->sk_user_data; + + skb_queue_purge(&sk->sk_receive_queue); + skb_queue_purge(&sk->sk_write_queue); + if (session) { sk->sk_user_data = NULL; BUG_ON(session->magic != L2TP_SESSION_MAGIC); @@ -488,9 +492,6 @@ static int pppol2tp_release(struct socke l2tp_session_queue_purge(session); sock_put(sk); } - skb_queue_purge(&sk->sk_receive_queue); - skb_queue_purge(&sk->sk_write_queue); - release_sock(sk); /* This will delete the session context via