Re: [PATCH] media:usb:cpia2: Properly check framebuffer mmap offsets

From: Hans Verkuil
Date: Sat Nov 09 2019 - 06:39:51 EST


Hi Greg,

On 11/8/19 9:49 PM, Greg Kroah-Hartman wrote:
> On Fri, Nov 08, 2019 at 09:50:36PM +0000, Omer Shalev wrote:
>> The cpai2 driver's mmap implementation wasn't properly check for all
>> possible offset values. Given a huge offset value , the calculation
>> start_offset + size can wrap around to a low value and pass the check
>
> I thought we checked that in the core of the kernel now, to keep all
> drivers from not having to do this type of thing (as they obviously all
> forgot to.) Why is this still needed here as well?

Where is that checked in the core? I couldn't find anything, but I might
have been looking in the wrong place.

Regards,

Hans

>
> thanks,
>
> greg k-h
>