Re: [Linux-kernel-mentees] [PATCH net] xdp: Prevent kernel-infoleak in xsk_getsockopt()

[Peilin Ye <yepeilin.cs@gmail.com>]

On Mon, Jul 27, 2020 at 10:07:20PM -0700, Song Liu wrote:
> On Mon, Jul 27, 2020 at 7:30 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
> >
> > xsk_getsockopt() is copying uninitialized stack memory to userspace when
> > `extra_stats` is `false`. Fix it by initializing `stats` with memset().
> >
> > Cc: stable@vger.kernel.org
> 
> 8aa5a33578e9 is not in stable branches yet, so we don't need to Cc stable.
> 
> > Fixes: 8aa5a33578e9 ("xsk: Add new statistics")
> > Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> > ---
> >  net/xdp/xsk.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> > index 26e3bba8c204..acf001908a0d 100644
> > --- a/net/xdp/xsk.c
> > +++ b/net/xdp/xsk.c
> > @@ -844,6 +844,8 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
> >                 bool extra_stats = true;
> >                 size_t stats_size;
> >
> > +               memset(&stats, 0, sizeof(stats));
> > +
> 
> xsk.c doesn't include linux/string.h directly, so using memset may break
> build for some config combinations. We can probably just use
> 
> struct xdp_statistics stats = {};

I see. I will send v2 soon. Thank you for reviewing the patch!

Peilin Ye