media: media_device_enum_links32: clean a reserved field

[ Upstream commit f4930887 ]

In v4l2-compliance utility, test MEDIA_IOC_ENUM_ENTITIES
will check whether reserved field of media_links_enum filled
with zero.

However, for 32 bit program, the reserved field is missing
copy from kernel space to user space in media_device_enum_links32
function.

This patch adds the cleaning a reserved field logic in
media_device_enum_links32 function.
Signed-off-by: Jungo Lin <jungo.lin@mediatek.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/media/media-device.c

@@ -487,6 +487,7 @@ static long media_device_enum_links32(struct media_device *mdev,
 {
 	struct media_links_enum links;
 	compat_uptr_t pads_ptr, links_ptr;
+	int ret;
 
 	memset(&links, 0, sizeof(links));
 
@@ -498,7 +499,13 @@ static long media_device_enum_links32(struct media_device *mdev,
 	links.pads = compat_ptr(pads_ptr);
 	links.links = compat_ptr(links_ptr);
 
-	return media_device_enum_links(mdev, &links);
+	ret = media_device_enum_links(mdev, &links);
+	if (ret)
+		return ret;
+
+	memset(ulinks->reserved, 0, sizeof(ulinks->reserved));
+
+	return 0;
 }
 
 #define MEDIA_IOC_ENUM_LINKS32		_IOWR('|', 0x02, struct media_links_enum32)