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

[AngeloGioacchino Del Regno]

Il 07/07/23 11:24, Zheng Wang ha scritto:
> 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
> Fixes: b2f0d2724ba4 ("[media] vcodec: mediatek: Add Mediatek JPEG Decoder Driver")
> Signed-off-by: Zheng Wang <zyytlz.wz at 163.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>