From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753335AbaD1Ba3 (ORCPT ); Sun, 27 Apr 2014 21:30:29 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43062 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752843AbaD1B3X (ORCPT ); Sun, 27 Apr 2014 21:29:23 -0400 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, "Nicholas Bellinger" , "Andy Grover" Date: Mon, 28 Apr 2014 02:11:22 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 87/94] target/tcm_fc: Fix use-after-free of ft_tpg In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 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 3.2.58-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andy Grover commit 2c42be2dd4f6586728dba5c4e197afd5cfaded78 upstream. ft_del_tpg checks tpg->tport is set before unlinking the tpg from the tport when the tpg is being removed. Set this pointer in ft_tport_create, or the unlinking won't happen in ft_del_tpg and tport->tpg will reference a deleted object. This patch sets tpg->tport in ft_tport_create, because that's what ft_del_tpg checks, and is the only way to get back to the tport to clear tport->tpg. The bug was occuring when: - lport created, tport (our per-lport, per-provider context) is allocated. tport->tpg = NULL - tpg created - a PRLI is received. ft_tport_create is called, tpg is found and tport->tpg is set - tpg removed. ft_tpg is freed in ft_del_tpg. Since tpg->tport was not set, tport->tpg is not cleared and points at freed memory - Future calls to ft_tport_create return tport via first conditional, instead of searching for new tpg by calling ft_lport_find_tpg. tport->tpg is still invalid, and will access freed memory. see https://bugzilla.redhat.com/show_bug.cgi?id=1071340 Signed-off-by: Andy Grover Signed-off-by: Nicholas Bellinger Signed-off-by: Ben Hutchings --- drivers/target/tcm_fc/tfc_sess.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/target/tcm_fc/tfc_sess.c +++ b/drivers/target/tcm_fc/tfc_sess.c @@ -72,6 +72,7 @@ static struct ft_tport *ft_tport_create( if (tport) { tport->tpg = tpg; + tpg->tport = tport; return tport; }