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@xxxxxxxxxxxxxxxxxxxxxxxxx
> Tested-by: syzbot+6bf9606ee955b646c0e1@xxxxxxxxxxxxxxxxxxxxxxxxx
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@xxxxxxxxx>
> ---
> 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?
Thanks
Sean
> u8 b[4] = { 0 };
> + int ret;
>
> *event = 0;
> *state = REMOTE_NO_KEY_PRESSED;
>
> - digitv_ctrl_msg(d,USB_READ_REMOTE,0,NULL,0,&key[1],4);
> -
> + ret = digitv_ctrl_msg(d, USB_READ_REMOTE, 0, NULL, 0, &key[1], 4);
> + if (ret < 0)
> + return ret;
> /* Tell the device we've read the remote. Not sure how necessary
> this is, but the Nebula SDK does it. */
> - digitv_ctrl_msg(d,USB_WRITE_REMOTE,0,b,4,NULL,0);
> + ret = digitv_ctrl_msg(d, USB_WRITE_REMOTE, 0, b, 4, NULL, 0);
> + if (ret < 0)
> + return ret;
>
> /* if something is inside the buffer, simulate key press */
> if (key[1] != 0)
> --
> 2.20.1
