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SubjectRe: [PATCH] media: dvb: check return value digitv_ctrl_msg
On Wed, Jan 15, 2020 at 05:32:26PM +0000, Sean Young wrote:
> Hello,
>
> On Tue, Dec 03, 2019 at 07:41:38AM +0700, Phong Tran wrote:
> > For fixing syzbot "KMSAN: uninit-value in digitv_rc_query"
> >
> > In scenario testing for syzbot, failure reading from
> > digitv_ctrl_msg() [1].
> >
> > Eg:
> > [ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0)
> >
> > digitv_rc_query() always return 0. But in this case a wrong thing happens.
> >
> > Reported-by: syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com
> > Tested-by: syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com
>
> A fix for this was already merged I'm afraid, see commit eecc70d22ae5
> ("media: digitv: don't continue if remote control state can't be read").
>
> > [1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000
> > [2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ
> >
> > Signed-off-by: Phong Tran <tranmanphong@gmail.com>
> > ---
> > drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c
> > index dd5bb230cec1..61bc8945e6b9 100644
> > --- a/drivers/media/usb/dvb-usb/digitv.c
> > +++ b/drivers/media/usb/dvb-usb/digitv.c
> > @@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = {
> > static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
> > {
> > int i;
> > - u8 key[5];
> > + u8 key[5] = { 0 };
>
> The merged commit does not change this line. Why was this changed?
>

It would fix the problem that key[0] is never initialized... But the
correct fix is to make key 4 elements long and delete key[0].

regards,
dan carpenter

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