media: info leak in __media_device_enum_links()

commit c88e739b upstream.

These structs have holes and reserved struct members which aren't
cleared.  I've added a memset() so we don't leak stack information.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/media/media-device.c

@@ -142,6 +142,8 @@ static long media_device_enum_links(struct media_device *mdev,
 
 		for (p = 0; p < entity->num_pads; p++) {
 			struct media_pad_desc pad;
+
+			memset(&pad, 0, sizeof(pad));
 			media_device_kpad_to_upad(&entity->pads[p], &pad);
 			if (copy_to_user(&links.pads[p], &pad, sizeof(pad)))
 				return -EFAULT;
@@ -159,6 +161,7 @@ static long media_device_enum_links(struct media_device *mdev,
 			if (entity->links[l].source->entity != entity)
 				continue;
 
+			memset(&link, 0, sizeof(link));
 			media_device_kpad_to_upad(entity->links[l].source,
 						  &link.source);
 			media_device_kpad_to_upad(entity->links[l].sink,