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")
Signed-off-by: Johan Hovold <[email protected]>
---
 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);
 
-- 
2.10.2

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to