Re: [PATCH] usbhid: fix info leak in hid_submit_ctrl

[Jiri Kosina]

On Sun, 25 Apr 2021, Anirudh Rayabharam wrote:

> In hid_submit_ctrl(), the way of calculating the report length doesn't
> take into account that report->size can be zero. When running the
> syzkaller reproducer, a report of size 0 causes hid_submit_ctrl) to
> calculate transfer_buffer_length as 16384. When this urb is passed to
> the usb core layer, KMSAN reports an info leak of 16384 bytes.
> 
> To fix this, first modify hid_report_len() to account for the zero
> report size case by using DIV_ROUND_UP for the division. Then, call it
> from hid_submit_ctrl().
> 
> Reported-by: syzbot+7c2bb71996f95a82524c@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Anirudh Rayabharam <mail@xxxxxxxxxxxxx>

Benjamin, could you please run this one through your regression testing 
machinery before we send it upstream?

Thanks,

-- 
Jiri Kosina
SUSE Labs