From 594c9b4b0acb9e3091c583958ee144b58d0e7bdd 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 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(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 99a0a5f1b400..d8d13eede6d9 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);