| From bda209b5a7d4dba97c37b3050c59794c02ad9e87 Mon Sep 17 00:00:00 2001 |
| From: Johan Hovold <johan@kernel.org> |
| 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 <gregkh@linuxfoundation.org> |
| Signed-off-by: Johan Hovold <johan@kernel.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| 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); |
| |
| -- |
| 2.12.0 |
| |