Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752515AbdFAP7Q (ORCPT ); Thu, 1 Jun 2017 11:59:16 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33913 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752284AbdFAPpP (ORCPT ); Thu, 1 Jun 2017 11:45:15 -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, "Johan Hovold" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 206/212] USB: serial: io_ti: fix information leak in completion handler In-Reply-To: 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: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1151 Lines: 33 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 654b404f2a222f918af9b0cd18ad469d0c941a8e upstream. Add missing sanity check to the bulk-in completion handler to avoid an integer underflow that can be triggered by a malicious device. This avoids leaking 128 kB of memory content from after the URB transfer buffer to user space. Fixes: 8c209e6782ca ("USB: make actual_length in struct urb field u32") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Johan Hovold Signed-off-by: Ben Hutchings --- drivers/usb/serial/io_ti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/serial/io_ti.c +++ b/drivers/usb/serial/io_ti.c @@ -1630,7 +1630,7 @@ static void edge_bulk_in_callback(struct port_number = edge_port->port->port_number; - if (edge_port->lsr_event) { + if (urb->actual_length > 0 && edge_port->lsr_event) { edge_port->lsr_event = 0; dev_dbg(dev, "%s ===== Port %u LSR Status = %02x, Data = %02x ======\n", __func__, port_number, edge_port->lsr_mask, *data);