From 2cdc8f729d953143b3bbdc56841bb6800752de7f Mon Sep 17 00:00:00 2001 From: Zheng Wang Date: Mon, 13 Mar 2023 16:31:20 +0000 Subject: [PATCH] media: cedrus: fix use after free bug in cedrus_remove due to race condition [ 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: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion") Signed-off-by: Zheng Wang Acked-by: Jernej Skrabec Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/staging/media/sunxi/cedrus/cedrus.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c index 55c54df..d241931 100644 --- a/drivers/staging/media/sunxi/cedrus/cedrus.c +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c @@ -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); -- 2.7.4