On Fri, Aug 04, 2017 at 11:09:24AM +0200, Thomas Huth wrote:
> Hi,
>
> On 03.08.2017 15:59, sohu0106 wrote:
> >
> > The stack object "kbdiacr" has a total size of 4 bytes. Its last 1 bytes
> > are padding bytes after "result" which are not initialized and leaked to
> > userland via "copy_to_user".
> >
> >
> > diff --git a/keyboard.c b/keyboard.c
> > index ba0e4f9..76a6d35 100644
> > --- a/keyboard.c
> > +++ b/keyboard.c
> > @@ -480,6 +480,8 @@ int kbd_ioctl(struct kbd_data *kbd, unsigned int cmd,
> > unsigned long arg)
> > struct kbdiacr diacr;
> > int i;
> >
> > + memset( &diacr, 0, sizeof(struct kbdiacr) );
> > +
>
> I think it would be nicer to simply init the struct with "= {}"
> directly, i.e.:
>
> struct kbdiacr diacr = {};
>
> And by the way, please have a look at the kernel patch submission
> guidelines first, especially the COO part here:
The patch doesn't make sense. There is no padding and therefore no
information leak.
