From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:45749 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932464AbbJZNo6 (ORCPT ); Mon, 26 Oct 2015 09:44:58 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Alexander Couzens , "David S. Miller" , Luis Henriques Subject: [PATCH 3.16.y-ckt 093/104] l2tp: protect tunnel->del_work by ref_count Date: Mon, 26 Oct 2015 13:43:15 +0000 Message-Id: <1445867006-18048-94-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1445867006-18048-1-git-send-email-luis.henriques@canonical.com> References: <1445867006-18048-1-git-send-email-luis.henriques@canonical.com> Sender: stable-owner@vger.kernel.org List-ID: 3.16.7-ckt19 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Couzens commit 06a15f51cf3618e32a73871ee6a547ef7fd902b5 upstream. There is a small chance that tunnel_free() is called before tunnel->del_work scheduled resulting in a zero pointer dereference. Signed-off-by: Alexander Couzens Acked-by: James Chapman Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- net/l2tp/l2tp_core.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index bea259043205..0c6a8f18b0fc 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1318,7 +1318,7 @@ static void l2tp_tunnel_del_work(struct work_struct *work) tunnel = container_of(work, struct l2tp_tunnel, del_work); sk = l2tp_tunnel_sock_lookup(tunnel); if (!sk) - return; + goto out; sock = sk->sk_socket; @@ -1339,6 +1339,8 @@ static void l2tp_tunnel_del_work(struct work_struct *work) } l2tp_tunnel_sock_put(sk); +out: + l2tp_tunnel_dec_refcount(tunnel); } /* Create a socket for the tunnel, if one isn't set up by @@ -1673,8 +1675,13 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create); */ int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) { + l2tp_tunnel_inc_refcount(tunnel); l2tp_tunnel_closeall(tunnel); - return (false == queue_work(l2tp_wq, &tunnel->del_work)); + if (false == queue_work(l2tp_wq, &tunnel->del_work)) { + l2tp_tunnel_dec_refcount(tunnel); + return 1; + } + return 0; } EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);