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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 020/223] media: mc-device.c: dont memset __user pointer contents
Date:   Fri,  2 Aug 2019 11:34:05 +0200
Message-Id: <20190802092240.375444660@linuxfoundation.org>
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[ Upstream commit 518fa4e0e0da97ea2e17c95ab57647ce748a96e2 ]

You can't memset the contents of a __user pointer. Instead, call copy_to_user to
copy links.reserved (which is zeroed) to the user memory.

This fixes this sparse warning:

SPARSE:drivers/media/mc/mc-device.c drivers/media/mc/mc-device.c:521:16:  warning: incorrect type in argument 1 (different address spaces)

Fixes: f49308878d720 ("media: media_device_enum_links32: clean a reserved field")

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/media-device.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 6062c0cfa632..73a2dba475d0 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -490,8 +490,9 @@ static long media_device_enum_links32(struct media_device *mdev,
 	if (ret)
 		return ret;
 
-	memset(ulinks->reserved, 0, sizeof(ulinks->reserved));
-
+	if (copy_to_user(ulinks->reserved, links.reserved,
+			 sizeof(ulinks->reserved)))
+		return -EFAULT;
 	return 0;
 }
 
-- 
2.20.1