media: uvcvideo: Fix memory leak if uvc_ctrl_add_mapping fails

Move all the life cycle of the name to add_mapping. This simplifies
the error handling inside uvc_ioctl_ctrl_map and solves a memory leak
when kemmdup fails.

Also make sure that for custom controls, the user provides a valid name.

Fixes: 07adedb5c606 ("media: uvcvideo: Use control names from framework")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/usb/uvc/uvc_ctrl.c

@@ -2188,11 +2188,21 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
 	if (map == NULL)
 		return -ENOMEM;
 
+	/* For UVCIOC_CTRL_MAP custom control */
+	if (mapping->name) {
+		map->name = kstrdup(mapping->name, GFP_KERNEL);
+		if (!map->name) {
+			kfree(map);
+			return -ENOMEM;
+		}
+	}
+
 	INIT_LIST_HEAD(&map->ev_subs);
 
 	size = sizeof(*mapping->menu_info) * mapping->menu_count;
 	map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
 	if (map->menu_info == NULL) {
+		kfree(map->name);
 		kfree(map);
 		return -ENOMEM;
 	}

drivers/media/usb/uvc/uvc_v4l2.c

@@ -42,12 +42,12 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
 	map->id = xmap->id;
 	/* Non standard control id. */
 	if (v4l2_ctrl_get_name(map->id) == NULL) {
-		map->name = kmemdup(xmap->name, sizeof(xmap->name),
-				    GFP_KERNEL);
-		if (!map->name) {
-			ret = -ENOMEM;
+		if (xmap->name[0] == '\0') {
+			ret = -EINVAL;
 			goto free_map;
 		}
+		xmap->name[sizeof(xmap->name) - 1] = '\0';
+		map->name = xmap->name;
 	}
 	memcpy(map->entity, xmap->entity, sizeof(map->entity));
 	map->selector = xmap->selector;