On Wed, May 5, 2021 at 2:42 PM Jiri Kosina <jikos@xxxxxxxxxx> wrote: > > 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? > I don't have a reproducer like syzbot has for the exact bug here, as I am relying on one real USB device to check if usbhid is not too broken. However, the test suite should catch if there is an error implied by the hid_report_len() change. Anyway, I manually started the job and will report when it is done. Cheers, Benjamin
