Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754267AbdCPPJP (ORCPT ); Thu, 16 Mar 2017 11:09:15 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60168 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbdCPOcq (ORCPT ); Thu, 16 Mar 2017 10:32:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold Subject: [PATCH 4.4 23/35] USB: serial: safe_serial: fix information leak in completion handler Date: Thu, 16 Mar 2017 23:29:42 +0900 Message-Id: <20170316142908.256103666@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170316142906.685052998@linuxfoundation.org> References: <20170316142906.685052998@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1032 Lines: 37 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 8c76d7cd520ebffc1ea9ea0850d87a224a50c7f2 upstream. Add missing sanity check to the bulk-in completion handler to avoid an integer underflow that could be triggered by a malicious device. This avoids leaking up to 56 bytes from after the URB transfer buffer to user space. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/safe_serial.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/usb/serial/safe_serial.c +++ b/drivers/usb/serial/safe_serial.c @@ -205,6 +205,11 @@ static void safe_process_read_urb(struct if (!safe) goto out; + if (length < 2) { + dev_err(&port->dev, "malformed packet\n"); + return; + } + fcs = fcs_compute10(data, length, CRC10_INITFCS); if (fcs) { dev_err(&port->dev, "%s - bad CRC %x\n", __func__, fcs);