Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966356AbcDLSIX (ORCPT ); Tue, 12 Apr 2016 14:08:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:49103 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965625AbcDLSIV (ORCPT ); Tue, 12 Apr 2016 14:08:21 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Oliver Neukum , Greg Kroah-Hartman , Moritz Muehlenhoff , Luis Henriques Subject: [PATCH 3.16.y-ckt 11/17] USB: cdc-acm: more sanity checking Date: Tue, 12 Apr 2016 19:07:58 +0100 Message-Id: <1460484484-22395-12-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1460484484-22395-1-git-send-email-luis.henriques@canonical.com> References: <1460484484-22395-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1278 Lines: 35 3.16.7-ckt27 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Oliver Neukum commit 8835ba4a39cf53f705417b3b3a94eb067673f2c9 upstream. An attack has become available which pretends to be a quirky device circumventing normal sanity checks and crashes the kernel by an insufficient number of interfaces. This patch adds a check to the code path for quirky devices. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman Cc: Moritz Muehlenhoff Signed-off-by: Luis Henriques --- drivers/usb/class/cdc-acm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 332be4c5745c..54061a3bc5e9 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1104,6 +1104,9 @@ static int acm_probe(struct usb_interface *intf, if (quirks == NO_UNION_NORMAL) { data_interface = usb_ifnum_to_if(usb_dev, 1); control_interface = usb_ifnum_to_if(usb_dev, 0); + /* we would crash */ + if (!data_interface || !control_interface) + return -ENODEV; goto skip_normal_probe; }