From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Date: Sun, 9 May 2021 08:24:02 +0000 (+0200)
Subject: media: v4l2-core: Avoid the dangling pointer in v4l2_fh_release
X-Git-Tag: v4.19.198~357
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7c1d06ec164d1e05635eafddf1594eda86d6b9a;p=thirdparty%2Fkernel%2Fstable.git

media: v4l2-core: Avoid the dangling pointer in v4l2_fh_release

[ 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>
---

diff --git a/drivers/media/v4l2-core/v4l2-fh.c b/drivers/media/v4l2-core/v4l2-fh.c
index c91a7bd3ecfc7..ac8282d059fca 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;
 }