On Tue, Jan 31, 2017 at 05:17:28PM +0100, Johan Hovold wrote:
> Make sure the received data has the required headers before parsing it.
> 
> Also drop the redundant urb-status check, which has already been handled
> by the caller.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Johan Hovold <[email protected]>
> ---
>  drivers/usb/serial/digi_acceleport.c | 38 
> ++++++++++++++++++++++--------------
>  1 file changed, 23 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/usb/serial/digi_acceleport.c 
> b/drivers/usb/serial/digi_acceleport.c
> index 3b610f1e3f7c..eb433922598c 100644
> --- a/drivers/usb/serial/digi_acceleport.c
> +++ b/drivers/usb/serial/digi_acceleport.c
> @@ -1398,25 +1398,30 @@ static int digi_read_inb_callback(struct urb *urb)
>  {
>       struct usb_serial_port *port = urb->context;
>       struct digi_port *priv = usb_get_serial_port_data(port);
> -     int opcode = ((unsigned char *)urb->transfer_buffer)[0];
> -     int len = ((unsigned char *)urb->transfer_buffer)[1];
> -     int port_status = ((unsigned char *)urb->transfer_buffer)[2];
> -     unsigned char *data = ((unsigned char *)urb->transfer_buffer) + 3;
> +     unsigned char *buf = urb->transfer_buffer;
> +     int opcode;
> +     int len;
> +     int port_status;
> +     unsigned char *data;
>       int flag, throttled;
> -     int status = urb->status;
> -
> -     /* do not process callbacks on closed ports */
> -     /* but do continue the read chain */
> -     if (urb->status == -ENOENT)
> -             return 0;
>  
>       /* short/multiple packet check */
> +     if (urb->actual_length < 2) {
> +             dev_warn(&port->dev, "short packet received\n");
> +             return -1;

Again, real error number?  -EINVAL?  -EIO?

> +     }
> +
> +     opcode = buf[0];
> +     len = buf[1];
> +
>       if (urb->actual_length != len + 2) {
> -             dev_err(&port->dev, "%s: INCOMPLETE OR MULTIPLE PACKET, "
> -                     "status=%d, port=%d, opcode=%d, len=%d, "
> -                     "actual_length=%d, status=%d\n", __func__, status,
> -                     priv->dp_port_num, opcode, len, urb->actual_length,
> -                     port_status);
> +             dev_err(&port->dev, "malformed packet received: port=%d, 
> opcode=%d, len=%d, actual_length=%u\n",
> +                     priv->dp_port_num, opcode, len, urb->actual_length);
> +             return -1;

Same here and elsewhere in this patch.

thanks,

greg k-h
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