Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752269AbdFAQ0W (ORCPT ); Thu, 1 Jun 2017 12:26:22 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33393 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbdFAPot (ORCPT ); Thu, 1 Jun 2017 11:44:49 -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" , "Greg Kroah-Hartman" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 090/212] USB: serial: digi_acceleport: fix OOB data sanity check 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: 1802 Lines: 51 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 2d380889215fe20b8523345649dee0579821800c upstream. Make sure to check for short transfers to avoid underflow in a loop condition when parsing the receive buffer. Also fix an off-by-one error in the incomplete sanity check which could lead to invalid data being parsed. Fixes: 8c209e6782ca ("USB: make actual_length in struct urb field u32") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Ben Hutchings --- drivers/usb/serial/digi_acceleport.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/drivers/usb/serial/digi_acceleport.c +++ b/drivers/usb/serial/digi_acceleport.c @@ -1484,16 +1484,20 @@ static int digi_read_oob_callback(struct struct usb_serial *serial = port->serial; struct tty_struct *tty; struct digi_port *priv = usb_get_serial_port_data(port); + unsigned char *buf = urb->transfer_buffer; int opcode, line, status, val; int i; unsigned int rts; + if (urb->actual_length < 4) + return -1; + /* handle each oob command */ - for (i = 0; i < urb->actual_length - 3;) { - opcode = ((unsigned char *)urb->transfer_buffer)[i++]; - line = ((unsigned char *)urb->transfer_buffer)[i++]; - status = ((unsigned char *)urb->transfer_buffer)[i++]; - val = ((unsigned char *)urb->transfer_buffer)[i++]; + for (i = 0; i < urb->actual_length - 4; i += 4) { + opcode = buf[i]; + line = buf[i + 1]; + status = buf[i + 2]; + val = buf[i + 3]; dev_dbg(&port->dev, "digi_read_oob_callback: opcode=%d, line=%d, status=%d, val=%d\n", opcode, line, status, val);