Re: [patch] gru: info leak in gru_get_config_info()

Robin Holt
2013-04-21T13:19:02Z

On Sun, Apr 21, 2013 at 01:56:57PM +0200, walter harms wrote:
>
>
> Am 21.04.2013 13:10, schrieb Dan Carpenter:
> > The "info.fill" array isn't initialized so it can leak uninitialized
> > stack information to user space.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >
> > diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
> > index 44d273c..ed5fc43 100644
> > --- a/drivers/misc/sgi-gru/grufile.c
> > +++ b/drivers/misc/sgi-gru/grufile.c
> > @@ -176,6 +176,7 @@ static long gru_get_config_info(unsigned long arg)
> > info.nodes = num_online_nodes();
> > info.blades = info.nodes / nodesperblade;
> > info.chiplets = GRU_CHIPLETS_PER_BLADE * info.blades;
> > + memset(&info.fill, 0, sizeof(info.fill));
> >
>
> the other way around (clear first all bytes) looks more easy
> in case someone will add more elements to the struct.
>
> memset(&info, 0, sizeof(info));
> info.nodes = num_online_nodes();
> info.blades = info.nodes / nodesperblade;

That does seem more safe.

Robin