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media: cedrus: fix use after free bug in cedrus_remove due to race condition

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[ Upstream commit 50d0a7aea4809cef87979d4669911276aa23b71f ]

In cedrus_probe, dev->watchdog_work is bound with cedrus_watchdog function.
In cedrus_device_run, it will started by schedule_delayed_work. If there is
an unfinished work in cedrus_remove, there may be a race condition and
trigger UAF bug.

CPU0                  CPU1

                    |cedrus_watchdog
cedrus_remove       |
  v4l2_m2m_release  |
  kfree(m2m_dev)    |
                    |
                    | v4l2_m2m_get_curr_priv
                    |   m2m_dev //use

Fix it by canceling the worker in cedrus_remove.

Fixes: 7c38a551bd ("media: cedrus: Add watchdog for job completion")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.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 16:31:20 +00:00 committed by Greg Kroah-Hartman
parent 231a6947ff
commit 2cdc8f729d
1 changed files with 1 additions and 0 deletions
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drivers/staging/media/sunxi/cedrus/cedrus.c
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@ -541,6 +541,7 @@ static int cedrus_remove(struct platform_device *pdev)
{
struct cedrus_dev *dev = platform_get_drvdata(pdev);
cancel_delayed_work_sync(&dev->watchdog_work);
if (media_devnode_is_registered(dev->mdev.devnode)) {
media_device_unregister(&dev->mdev);
v4l2_m2m_unregister_media_controller(dev->m2m_dev);