Re: [PATCH 03/14] media: ov6650: Fix unverified arguments used in .set_fmt()

Sakari Ailus
2019-04-30T13:58:21Z

Hi Janusz,

On Mon, Apr 08, 2019 at 11:42:31PM +0200, Janusz Krzysztofik wrote:
> Commit 717fd5b4907ad ("[media] v4l2: replace try_mbus_fmt by set_fmt")
> converted a former ov6650_try_fmt() video operation callback to an
> ov6650_set_fmt() pad operation callback. However, the function does not
> verify correctness of user provided format->which flag and pad config
> pointer arguments. Fix it.
>
> Fixes: 717fd5b4907ad ("[media] v4l2: replace try_mbus_fmt by set_fmt")
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/media/i2c/ov6650.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/media/i2c/ov6650.c b/drivers/media/i2c/ov6650.c
> index 007f0ca24913..3062c9a6c57b 100644
> --- a/drivers/media/i2c/ov6650.c
> +++ b/drivers/media/i2c/ov6650.c
> @@ -679,6 +679,17 @@ static int ov6650_set_fmt(struct v4l2_subdev *sd,
> if (format->pad)
> return -EINVAL;
>
> + switch (format->which) {
> + case V4L2_SUBDEV_FORMAT_ACTIVE:
> + break;
> + case V4L2_SUBDEV_FORMAT_TRY:
> + if (cfg)
> + break;
> + /* fall through */
> + default:
> + return -EINVAL;
> + }

For this to return an error, there would need to be a problem on the
caller's side. In other words, this isn't supposed to happen.

Instead of adding such checks to all drivers, I think they instead should
be added to the caller's side. The checks already exist for uAPI, but not
for other drivers.

The same applies to patches until 7th (including).

> +
> if (is_unscaled_ok(mf->width, mf->height, &priv->rect))
> v4l_bound_align_image(&mf->width, 2, W_CIF, 1,
> &mf->height, 2, H_CIF, 1, 0);

--
Kind regards,

Sakari Ailus