Re: [PATCH] USB: serial: option: add interface-number sanity check to flag handling

[Greg KH]

On Wed, Dec 09, 2020 at 11:42:21AM +0100, Johan Hovold wrote:
> Add an interface-number sanity check before testing the device flags to
> avoid relying on undefined behaviour when left shifting in case a device
> uses an interface number greater than or equal to BITS_PER_LONG (i.e. 64
> or 32).
> 
> Reported-by: syzbot+8881b478dad0a7971f79@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: c3a65808f04a ("USB: serial: option: reimplement interface masking")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>