[RESEND PATCH v2] media: mtk-jpeg: Fix use after free bug due to uncanceled work

[Zheng Hacker]

Friendly ping

Zheng Hacker <hackerzheng666 at gmail.com> 于2023年7月16日周日 00:08写道：
>
> Hi,
>
> This issue has not been resolved for a long time. Is there anyone who can help?
>
> Best regards,
> Zheng
>
> Alexandre Mergnat <amergnat at baylibre.com> 于2023年7月7日周五 22:11写道：
> >
> >
> >
> > 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 at baylibre.com>
> >
> > --
> > Regards,
> > Alexandre