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From:   Zheng Hacker <hackerzheng666@gmail.com>
Date:   Tue, 18 Jul 2023 11:07:01 +0800
Message-ID: <CAJedcCyKv-hdDhWcogDZrC-kY6qtO-H1fDYqjTXMJvCR19MxYg@mail.gmail.com>
Subject: Re: [RESEND PATCH v2] media: mtk-jpeg: Fix use after free bug due to
 uncanceled work
To:     Alexandre Mergnat <amergnat@baylibre.com>
Cc:     Zheng Wang <zyytlz.wz@163.com>, Kyrie.Wu@mediatek.com,
        bin.liu@mediatek.com, mchehab@kernel.org, matthias.bgg@gmail.com,
        angelogioacchino.delregno@collabora.com,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, Irui.Wang@mediatek.com,
        security@kernel.org, 1395428693sheep@gmail.com,
        alex000young@gmail.com
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Friendly ping

Zheng Hacker <hackerzheng666@gmail.com> =E4=BA=8E2023=E5=B9=B47=E6=9C=8816=
=E6=97=A5=E5=91=A8=E6=97=A5 00:08=E5=86=99=E9=81=93=EF=BC=9A
>
> Hi,
>
> This issue has not been resolved for a long time. Is there anyone who can=
 help?
>
> Best regards,
> Zheng
>
> Alexandre Mergnat <amergnat@baylibre.com> =E4=BA=8E2023=E5=B9=B47=E6=9C=
=887=E6=97=A5=E5=91=A8=E4=BA=94 22:11=E5=86=99=E9=81=93=EF=BC=9A
> >
> >
> >
> > On 07/07/2023 11:24, Zheng Wang wrote:
> > > In mtk_jpeg_probe, &jpeg->job_timeout_work is bound with
> > > mtk_jpeg_job_timeout_work. Then mtk_jpeg_dec_device_run
> > > and mtk_jpeg_enc_device_run may be called to start the
> > > work.
> > > If we remove the module which will call mtk_jpeg_remove
> > > to make cleanup, there may be a unfinished work. The
> > > possible sequence is as follows, which will cause a
> > > typical UAF bug.
> > >
> > > Fix it by canceling the work before cleanup in the mtk_jpeg_remove
> > >
> > > CPU0                  CPU1
> > >
> > >                      |mtk_jpeg_job_timeout_work
> > > mtk_jpeg_remove     |
> > >    v4l2_m2m_release  |
> > >      kfree(m2m_dev); |
> > >                      |
> > >                      | v4l2_m2m_get_curr_priv
> > >                      |   m2m_dev->curr_ctx //use
> >
> > Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
> >
> > --
> > Regards,
> > Alexandre