From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753764AbdCFJXB (ORCPT ); Mon, 6 Mar 2017 04:23:01 -0500 Received: from mx2.suse.de ([195.135.220.15]:37299 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752970AbdCFJOA (ORCPT ); Mon, 6 Mar 2017 04:14:00 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Johan Hovold , Jiri Slaby Subject: [PATCH 3.12 080/113] USB: serial: ftdi_sio: fix modem-status error handling Date: Mon, 6 Mar 2017 10:11:44 +0100 Message-Id: <164e029c1313e57dc7445abf2d38907e5a4612ca.1488791431.git.jslaby@suse.cz> X-Mailer: git-send-email 2.12.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 427c3a95e3e29e65f59d99aaf320d7506f3eed57 upstream. Make sure to detect short responses when fetching the modem status in order to avoid parsing uninitialised buffer data and having bits of it leak to user space. Note that we still allow for short 1-byte responses. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Jiri Slaby --- drivers/usb/serial/ftdi_sio.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index d1b76b0a67df..5ed104787474 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2465,8 +2465,12 @@ static int ftdi_get_modem_status(struct usb_serial_port *port, FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE, 0, priv->interface, buf, len, WDR_TIMEOUT); - if (ret < 0) { + + /* NOTE: We allow short responses and handle that below. */ + if (ret < 1) { dev_err(&port->dev, "failed to get modem status: %d\n", ret); + if (ret >= 0) + ret = -EIO; ret = usb_translate_errors(ret); goto out; } -- 2.12.0