From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753600AbdKFXYw (ORCPT ); Mon, 6 Nov 2017 18:24:52 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51661 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223AbdKFXXv (ORCPT ); Mon, 6 Nov 2017 18:23:51 -0500 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, "Guillaume Nault" , "David S. Miller" Date: Mon, 06 Nov 2017 23:03:07 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 057/147] l2tp: initialise session's refcount before making it reachable In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.95-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault commit 9ee369a405c57613d7c83a3967780c3e30c52ecc upstream. Sessions must be fully initialised before calling l2tp_session_add_to_tunnel(). Otherwise, there's a short time frame where partially initialised sessions can be accessed by external users. Fixes: dbdbc73b4478 ("l2tp: fix duplicate session creation") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller [bwh: Backported to 3.2: keep using l2tp_session_inc_refcount()] Signed-off-by: Ben Hutchings --- net/l2tp/l2tp_core.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1715,6 +1715,8 @@ struct l2tp_session *l2tp_session_create l2tp_session_set_header_len(session, tunnel->version); + l2tp_session_inc_refcount(session); + err = l2tp_session_add_to_tunnel(tunnel, session); if (err) { kfree(session); @@ -1722,10 +1724,6 @@ struct l2tp_session *l2tp_session_create return ERR_PTR(err); } - /* Bump the reference count. The session context is deleted - * only when this drops to zero. - */ - l2tp_session_inc_refcount(session); l2tp_tunnel_inc_refcount(tunnel); /* Ensure tunnel socket isn't deleted */