Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S937591AbdCJNzE (ORCPT <rfc822;w@1wt.eu>);
        Fri, 10 Mar 2017 08:55:04 -0500
Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42774 "EHLO
        shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK)
        by vger.kernel.org with ESMTP id S934115AbdCJLwF (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 10 Mar 2017 06:52:05 -0500
Content-Type: text/plain; charset="UTF-8"
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC: akpm@linux-foundation.org, "Johan Hovold" <johan@kernel.org>
Date: Fri, 10 Mar 2017 11:46:22 +0000
Message-ID: <lsq.1489146382.760513259@decadent.org.uk>
X-Mailer: LinuxStableQueue (scripts by bwh)
Subject: [PATCH 3.16 158/370] USB: serial: io_ti: fix NULL-deref at open
In-Reply-To: <lsq.1489146380.780052105@decadent.org.uk>
X-SA-Exim-Connect-IP: 82.70.136.246
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: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1559
Lines: 41

3.16.42-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit a323fefc6f5079844dc62ffeb54f491d0242ca35 upstream.

Fix NULL-pointer dereference when clearing halt at open should a
malicious device lack the expected endpoints when in download mode.

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
[<bf011ed8>] (edge_open [io_ti]) from [<bf000118>] (serial_port_activate+0x68/0x98 [usbserial])
[<bf000118>] (serial_port_activate [usbserial]) from [<c0470ca4>] (tty_port_open+0x9c/0xe8)
[<c0470ca4>] (tty_port_open) from [<bf000da0>] (serial_open+0x48/0x6c [usbserial])
[<bf000da0>] (serial_open [usbserial]) from [<c0469178>] (tty_open+0xcc/0x5cc)

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/usb/serial/io_ti.c | 7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2383,6 +2383,13 @@ static int edge_startup(struct usb_seria
 	struct edgeport_serial *edge_serial;
 	int status;
 
+	/* Make sure we have the required endpoints when in download mode. */
+	if (serial->interface->cur_altsetting->desc.bNumEndpoints > 1) {
+		if (serial->num_bulk_in < serial->num_ports ||
+				serial->num_bulk_out < serial->num_ports)
+			return -ENODEV;
+	}
+
 	/* create our private serial structure */
 	edge_serial = kzalloc(sizeof(struct edgeport_serial), GFP_KERNEL);
 	if (!edge_serial)