Re: [PATCH 1/7] Input: pegasus_notetaker: fix endpoint sanity check

[Martin Kepplinger]

On 10.12.19 12:37, Johan Hovold wrote:
> The driver was checking the number of endpoints of the first alternate
> setting instead of the current one, something which could be used by a
> malicious device (or USB descriptor fuzzer) to trigger a NULL-pointer
> dereference.
> 
> Fixes: 1afca2b66aac ("Input: add Pegasus Notetaker tablet driver")
> Cc: stable <stable@xxxxxxxxxxxxxxx>     # 4.8
> Cc: Martin Kepplinger <martink@xxxxxxxxx>
> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
> ---
>  drivers/input/tablet/pegasus_notetaker.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
> index a1f3a0cb197e..38f087404f7a 100644
> --- a/drivers/input/tablet/pegasus_notetaker.c
> +++ b/drivers/input/tablet/pegasus_notetaker.c
> @@ -275,7 +275,7 @@ static int pegasus_probe(struct usb_interface *intf,
>  		return -ENODEV;
>  
>  	/* Sanity check that the device has an endpoint */
> -	if (intf->altsetting[0].desc.bNumEndpoints < 1) {
> +	if (intf->cur_altsetting->desc.bNumEndpoints < 1) {
>  		dev_err(&intf->dev, "Invalid number of endpoints\n");
>  		return -EINVAL;
>  	}
> 

Acked-by: Martin Kepplinger <martink@xxxxxxxxx>