[PATCH 4.19 064/421] media: v4l2-core: Avoid the dangling pointer in v4l2_fh_release

Greg Kroah-Hartman
2021-07-19T16:07:55Z

From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

[ Upstream commit 7dd0c9e547b6924e18712b6b51aa3cba1896ee2c ]

A use after free bug caused by the dangling pointer
filp->privitate_data in v4l2_fh_release.
See https://lore.kernel.org/patchwork/patch/1419058/.

My patch sets the dangling pointer to NULL to provide
robust.

Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/v4l2-core/v4l2-fh.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/media/v4l2-core/v4l2-fh.c b/drivers/media/v4l2-core/v4l2-fh.c
index c91a7bd3ecfc..ac8282d059fc 100644
--- a/drivers/media/v4l2-core/v4l2-fh.c
+++ b/drivers/media/v4l2-core/v4l2-fh.c
@@ -104,6 +104,7 @@ int v4l2_fh_release(struct file *filp)
v4l2_fh_del(fh);
v4l2_fh_exit(fh);
kfree(fh);
+ filp->private_data = NULL;
}
return 0;
}
--
2.30.2