Re: [PATCH 073/190] Revert "media: rcar_drif: fix a memory disclosure"

[Laurent Pinchart]

Hi Geert,

On Wed, Apr 21, 2021 at 08:58:22PM +0200, Geert Uytterhoeven wrote:
> On Wed, Apr 21, 2021 at 3:06 PM Greg Kroah-Hartman wrote:
> > This reverts commit d39083234c60519724c6ed59509a2129fd2aed41.
> >
> > Commits from @umn.edu addresses have been found to be submitted in "bad
> > faith" to try to test the kernel community's ability to review "known
> > malicious" changes.  The result of these submissions can be found in a
> > paper published at the 42nd IEEE Symposium on Security and Privacy
> > entitled, "Open Source Insecurity: Stealthily Introducing
> > Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> > of Minnesota) and Kangjie Lu (University of Minnesota).
> >
> > Because of this, all submissions from this group must be reverted from
> > the kernel tree and will need to be re-reviewed again to determine if
> > they actually are a valid fix.  Until that work is complete, remove this
> > change to ensure that no problems are being introduced into the
> > codebase.
> >
> > Cc: Kangjie Lu <kjlu@xxxxxxx>
> > Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> > Cc: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> > Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> Upon a second look, I still see nothing wrong with the original commit.
> However, as I'm no v4l expert, I'd like to defer to the experts for final
> judgement.

It seems fine to me, but it also seems unneeded, as the V4L2 core clears
the whole f->fmt union before calling this operation. The revert will
this improve performance very slightly.

> > --- a/drivers/media/platform/rcar_drif.c
> > +++ b/drivers/media/platform/rcar_drif.c
> > @@ -915,7 +915,6 @@ static int rcar_drif_g_fmt_sdr_cap(struct file *file, void *priv,
> >  {
> >         struct rcar_drif_sdr *sdr = video_drvdata(file);
> >
> > -       memset(f->fmt.sdr.reserved, 0, sizeof(f->fmt.sdr.reserved));
> >         f->fmt.sdr.pixelformat = sdr->fmt->pixelformat;
> >         f->fmt.sdr.buffersize = sdr->fmt->buffersize;
> >

-- 
Regards,

Laurent Pinchart