From e3e574ad85a208cb179f33720bb5f12b453de33c Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 12 Jan 2017 14:56:12 +0100 Subject: [PATCH] USB: serial: ftdi_sio: fix latency-timer error handling 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 --- drivers/usb/serial/ftdi_sio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 6dee20fc7e45..b064fad8e3ee 100644 --- 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_serial_port *port) 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);