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From:   Fabrizio Castro <fabrizio.castro.jz@renesas.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Kangjie Lu <kjlu@umn.edu>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        =?iso-8859-1?Q?Niklas_S=F6derlund?= 
        <niklas.soderlund+renesas@ragnatech.se>,
        Chris Paterson <Chris.Paterson2@renesas.com>,
        Biju Das <biju.das.jz@bp.renesas.com>,
        Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Phil Edworthy <phil.edworthy@renesas.com>
Subject: RE: [PATCH 073/190] Revert "media: rcar_drif: fix a memory
 disclosure"
Thread-Topic: [PATCH 073/190] Revert "media: rcar_drif: fix a memory
 disclosure"
Thread-Index: AQHXNq+r2FQrjpIKCESqwpCja0Wk4aq/UzoAgAAoHoCAAKDbgIAACOsAgAAaRACAAAQ7MA==
Date:   Thu, 22 Apr 2021 09:21:13 +0000
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References: <20210421130105.1226686-1-gregkh@linuxfoundation.org>
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        <c8dbe373-8910-5b34-ce71-cad1bcab2d71@xs4all.nl>
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Dear All,

> From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Sent: 22 April 2021 10:04
> Subject: Re: [PATCH 073/190] Revert "media: rcar_drif: fix a memory
> disclosure"
>=20
> Em Thu, 22 Apr 2021 09:29:36 +0200
> Hans Verkuil <hverkuil-cisco@xs4all.nl> escreveu:
>=20
> > On 22/04/2021 08:57, Geert Uytterhoeven wrote:
> > > Hi Laurent,
> > >
> > > On Wed, Apr 21, 2021 at 11:22 PM Laurent Pinchart
> > > <laurent.pinchart@ideasonboard.com> wrote:
> > >> 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, remov=
e
> this
> > >>>> change to ensure that no problems are being introduced into the
> > >>>> codebase.
> > >>>>
> > >>>> Cc: Kangjie Lu <kjlu@umn.edu>
> > >>>> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> > >>>> Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> > >>>> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> > >>>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > >>>
> > >>> 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 wil=
l
> > >> this improve performance very slightly.
> > >
> > > Hmm, that means very recent commit f12b81e47f48940a ("media: core
> > > headers: fix kernel-doc warnings") is not fully correct, as it added
> > > kerneldoc stating this is the responsibility of the driver:
> > >
> > > + * @reserved:          drivers and applications must zero this array
> >
> > Actually, it is the V4L2 core used by the driver that zeroes this. So
> > drivers don't need to do this, it's done for them. It used to be the
> > responsibility of the driver itself, but this was all moved to the core
> > framework a long time ago since, duh!, drivers always forgot this :-)
> >
> > >
> > > Anyway, it doesn't look like this umn.edu patch introduced a bug.
> >
> > I haven't seen any bugs introduced by the media patches from umn.edu.
>=20
> Hi Greg,
>=20
> I also double-checked all media revert patches from:
>=20
> 	git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
> umn.edu-reverts
>=20
> currently on this patch:
> 	6f4747a872ad Revert "ethtool: fix a potential missing-check bug"
>=20
> That's a summary of what I found:
>=20
> All of those should be dropped from your tree:
>=20
> 	84fdb5856edd	Revert "media: si2165: fix a missing check of
> return value"
> 	867043f2206e	Revert "media: video-mux: fix null pointer
> dereferences"
> 	78ae4b621297	Revert "media: cx231xx: replace BUG_ON with
> recovery code"
> 	5be328a55817	Revert "media: saa7146: Avoid using BUG_ON as an
> assertion"
> 	81ce83158d22	Revert "media: davinci/vpfe_capture.c: Avoid
> BUG_ON for register failure"
> 	3319b39504b8	Revert "media: media/saa7146: fix incorrect
> assertion in saa7146_buffer_finish"
> 	b393f7cb29a2	Revert "media: rcar-vin: Fix a reference count
> leak."
> 	197bc5d03682	Revert "media: rcar-vin: Fix a reference count
> leak."
> 	2fd9cf68bbb6	Revert "media: rockchip/rga: Fix a reference count
> leak."
> 	d1e4614eca24	Revert "media: platform: fcp: Fix a reference
> count leak."
> 	416e8a6ae07f	Revert "media: camss: Fix a reference count leak."
> 	06b793ae497b	Revert "media: s5p-mfc: Fix a reference count
> leak"
> 	8f9fc14a7cc9	Revert "media: stm32-dcmi: Fix a reference count
> leak"
> 	556e1f86ba24	Revert "media: ti-vpe: Fix a missing check and
> reference count leak"
> 	5f5b1722ad0d	Revert "media: exynos4-is: Fix a reference count
> leak"
> 	f4c758c6c1cb	Revert "media: exynos4-is: Fix a reference count
> leak due to pm_runtime_get_sync"
> 	beb717878c73	Revert "media: exynos4-is: Fix several reference
> count leaks due to pm_runtime_get_sync
> 	7066ec748bfd	Revert "media: sti: Fix reference count leaks"
> 	cdd117093b19	Revert "media: st-delta: Fix reference count leak
> in delta_run_work"
>=20
> As, after my re-check, they all seem to be addressing real issues. So,
> NACK on those.
>=20
> This patch (073/190):
>=20
> 	899ab4671bc0	Revert "media: rcar_drif: fix a memory disclosure"
>=20
> While it doesn't hurt, it is useless, as the media core already
> prevents memory disclosure. So, it should be reverted.
>=20
> So, for patch 073/190:
>=20
> Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

I agree, this patch should be reverted.

Reviewed-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>

>=20
> Thanks,
> Mauro