[patch 2/2] staging: line6: use after free bug requesting version

[Stefan Hajnoczi]

On Wed, Dec 5, 2012 at 7:44 PM, Dan Carpenter <dan.carpenter at oracle.com> wrote:
> diff --git a/drivers/staging/line6/driver.c b/drivers/staging/line6/driver.c
> index 8a5d89e..884e0d8 100644
> --- a/drivers/staging/line6/driver.c
> +++ b/drivers/staging/line6/driver.c
> @@ -110,7 +110,7 @@ struct message {
>  */
>  static void line6_data_received(struct urb *urb);
>  static int line6_send_raw_message_async_part(struct message *msg,
> -                                            struct urb *urb);
> +                                            struct urb *urb, int free);

s/int/bool/

>
>  /*
>         Start to listen on endpoint.
> @@ -219,24 +219,42 @@ static void line6_async_request_sent(struct urb *urb)
>                 usb_free_urb(urb);
>                 kfree(msg);
>         } else
> -               line6_send_raw_message_async_part(msg, urb);
> +               line6_send_raw_message_async_part(msg, urb, 0);
> +}

I'd add a bool free_buffer field to struct message and simply modify
line6_async_request_sent() to do:

if (msg->free_buffer)
         kfree(msg->buffer);

Then you don't need line6_async_request_sent_free_buffer() and
line6_send_raw_message_async_part() doesn't need to take a bool free
argument since struct message already contains that information.  It
would make the code simpler.