drm_lease.c: copy user-array safely

Currently, there is no overflow-check with memdup_user().

Use the new function memdup_array_user() instead of memdup_user() for
duplicating the user-space array safely.

Suggested-by: David Airlie <[email protected]>
Signed-off-by: Philipp Stanner <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Zack Rusin <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Philipp Stanner

drivers/gpu/drm/drm_lease.c

@@ -510,8 +510,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	/* Handle leased objects, if any */
 	idr_init(&leases);
 	if (object_count != 0) {
-		object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
-					 array_size(object_count, sizeof(__u32)));
+		object_ids = memdup_array_user(u64_to_user_ptr(cl->object_ids),
+					       object_count, sizeof(__u32));
 		if (IS_ERR(object_ids)) {
 			ret = PTR_ERR(object_ids);
 			idr_destroy(&leases);