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media: rkvdec: fix use after free bug in rkvdec_remove

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[ Upstream commit 3228cec23b ]

In rkvdec_probe, rkvdec->watchdog_work is bound with
rkvdec_watchdog_func. Then rkvdec_vp9_run may
be called to start the work.

If we remove the module which will call rkvdec_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 rkvdec_remove.

CPU0                  CPU1

                    |rkvdec_watchdog_func
rkvdec_remove       |
 rkvdec_v4l2_cleanup|
  v4l2_m2m_release  |
    kfree(m2m_dev); |
                    |
                    | v4l2_m2m_get_curr_priv
                    |   m2m_dev->curr_ctx //use

Fixes: cd33c83044 ("media: rkvdec: Add the rkvdec driver")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zheng Wang
2023-03-13 16:42:20 +00:00
committed by Greg Kroah-Hartman
parent d991f6139f
commit cac0f4f36e
1 changed files with 2 additions and 0 deletions
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2
drivers/staging/media/rkvdec/rkvdec.c
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@@ -1042,6 +1042,8 @@ static int rkvdec_remove(struct platform_device *pdev)
{
struct rkvdec_dev *rkvdec = platform_get_drvdata(pdev);
cancel_delayed_work_sync(&rkvdec->watchdog_work);
rkvdec_v4l2_cleanup(rkvdec);
pm_runtime_disable(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);