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References: <20230717-uvc-oob-v2-1-c7745a8d5847@chromium.org> <20230725213451.GU31069@pendragon.ideasonboard.com>
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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Wed, 26 Jul 2023 08:24:50 +0200
Message-ID: <CANiDSCttkqows7PZS823Jpk-CqK9Gz2rujF_R4SPDi=wcPJ2LA@mail.gmail.com>
Subject: Re: [PATCH v2] media: uvcvideo: Fix OOB read
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        stable@kernel.org, Zubin Mithra <zsm@chromium.org>
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Hi Laurent

Thanks for the review!

On Tue, 25 Jul 2023 at 23:34, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Thu, Jul 20, 2023 at 05:46:54PM +0000, Ricardo Ribalda wrote:
> > If the index provided by the user is bigger than the mask size, we might do an
> > out of bound read.
> >
> > CC: stable@kernel.org
> > Fixes: 40140eda661e ("media: uvcvideo: Implement mask for V4L2_CTRL_TYPE_MENU")
> > Reported-by: Zubin Mithra <zsm@chromium.org>
>
> checkpatch now requests a Reported-by tag to be immediately followed by
> a Closes tag that contains the URL to the report. Could you please
> provide that ?
>
I saw that, but the URL is kind of private:

Closes: http://issuetracker.google.com/issues/289975230

> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> > Avoid reading index >= 31
> > ---
> > Changes in v2:
> > - Use BITS_PER_TYPE instead of 32 (thanks Sergey).
> > - Add Reported-by tag.
> > - Link to v1: https://lore.kernel.org/r/20230717-uvc-oob-v1-1-f5b9b4aba3b4@chromium.org
> > ---
> >  drivers/media/usb/uvc/uvc_ctrl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 5e9d3da862dd..e59a463c2761 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -1402,6 +1402,9 @@ int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> >       query_menu->id = id;
> >       query_menu->index = index;
> >
> > +     if (index >= BITS_PER_TYPE(mapping->menu_mask))
> > +             return -EINVAL;
> > +
>
> I'd move this a few lines up, before setting query_menu.
>

SGTM, I just wanted to clear all the fields to mimic the other error
paths of the function.

> With those minor changes,
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> There's no need for a v3, I can handle the changes locally, but I need
> the URL for the Closes tag.
>
> >       ret = mutex_lock_interruptible(&chain->ctrl_mutex);
> >       if (ret < 0)
> >               return -ERESTARTSYS;
> >
> > ---
> > base-commit: fdf0eaf11452d72945af31804e2a1048ee1b574c
> > change-id: 20230717-uvc-oob-4b0148a00417
>
> --
> Regards,
>
> Laurent Pinchart


-- 
Ricardo Ribalda