From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johan Hovold Subject: [PATCH 4.9 063/103] USB: serial: ftdi_sio: fix latency-timer error handling Date: Thu, 11 May 2017 16:12:32 +0200 Message-Id: <20170511141215.685277182@linuxfoundation.org> In-Reply-To: <20170511141210.778405364@linuxfoundation.org> References: <20170511141210.778405364@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit e3e574ad85a208cb179f33720bb5f12b453de33c upstream. Make sure to detect short responses when reading the latency timer to avoid using stale buffer data. Note that no heap data would currently leak through sysfs as ASYNC_LOW_LATENCY is set by default. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1439,10 +1439,13 @@ static int read_latency_timer(struct usb FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE, 0, priv->interface, buf, 1, WDR_TIMEOUT); - if (rv < 0) + if (rv < 1) { dev_err(&port->dev, "Unable to read latency timer: %i\n", rv); - else + if (rv >= 0) + rv = -EIO; + } else { priv->latency = buf[0]; + } kfree(buf);