Re: [PATCH] usb: gadget: uvc: Fix ERR_PTR dereference in uvc_v4l2.c

Laurent Pinchart
2024-08-02T18:38:11Z

Hi Abhishek,

(CC'ing Michael Grzeschik)

Thank you for the patch.

On Fri, Aug 02, 2024 at 11:32:47PM +0530, Abhishek Tamboli wrote:
> Fix potential dereferencing of ERR_PTR() in find_format_by_pix()
> and uvc_v4l2_enum_format().
>
> Fix the following smatch errors:
>
> drivers/usb/gadget/function/uvc_v4l2.c:124 find_format_by_pix()
> error: 'fmtdesc' dereferencing possible ERR_PTR()
> drivers/usb/gadget/function/uvc_v4l2.c:392 uvc_v4l2_enum_format()
> error: 'fmtdesc' dereferencing possible ERR_PTR()
>
> Signed-off-by: Abhishek Tamboli <abhishektamboli9@gmail.com>
> ---
> drivers/usb/gadget/function/uvc_v4l2.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index a024aecb76dc..9dd602a742c4 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -121,6 +121,9 @@ static struct uvcg_format *find_format_by_pix(struct uvc_device *uvc,
> list_for_each_entry(format, &uvc->header->formats, entry) {
> const struct uvc_format_desc *fmtdesc = to_uvc_format(format->fmt);
>
> + if (IS_ERR(fmtdesc))
> + continue;
> +
> if (fmtdesc->fcc == pixelformat) {
> uformat = format->fmt;
> break;
> @@ -389,6 +392,9 @@ uvc_v4l2_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
> return -EINVAL;
>
> fmtdesc = to_uvc_format(uformat);
> + if (IS_ERR(fmtdesc))
> + return -EINVAL;
> +
> f->pixelformat = fmtdesc->fcc;
>
> return 0;

Michael, you authored this, I'll let you review the patch and decide if
this is a false positive.

--
Regards,

Laurent Pinchart