On Mon, Jul 27, 2020 at 09:25:16AM +0200, Arnd Bergmann wrote: > On Mon, Jul 27, 2020 at 12:28 AM Peilin Ye <yepeilin.cs@xxxxxxxxx> wrote: > > > > video_put_user() is copying uninitialized stack memory to userspace due > > to the compiler not initializing holes in the structures declared on the > > stack. Fix it by initializing `ev32` and `vb32` using memset(). > > > > Reported-and-tested-by: syzbot+79d751604cb6f29fbf59@xxxxxxxxxxxxxxxxxxxxxxxxx > > Link: https://syzkaller.appspot.com/bug?extid=79d751604cb6f29fbf59 > > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > Signed-off-by: Peilin Ye <yepeilin.cs@xxxxxxxxx> > > Thanks a lot for addressing this! I now see that I actually created a similar > bugfix for it back in January, but for some reason that got stuck in my > backlog and I never wrote a proper description for it or sent it out to the > list, sorry about that. I would hope we could find a way to have either > the compiler or sparse warn if we copy uninitialized data to user space, > but we now don't even check for that within the kernel any more. I am glad to be of help! > I would suggest adding these tags to the patch, to ensure it gets backported > to stable kernels as needed: > > Cc: stable@xxxxxxxxxxxxxxx > Fixes: 1a6c0b36dd19 ("media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI") > Fixes: 577c89b0ce72 ("media: v4l2-core: fix v4l2_buffer handling for > time64 ABI") > > In addition to > > Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx> Sure, I will send a v4 soon. Thank you for reviewing the patch. Peilin Ye
