REST API: Don’t remove unregistered properties from objects in schema.

In r41727 the ability to sanitise and validate objects from JSON schema was added, with a whitelist approach. It was decided we should pass through all non-registered properties to reflect the behaviour of the root object in register_rest_route. To prevent arbitrary extra data via setting objects, we force additionalProperties to false in the settings endpoint.

See #38583.
Built from https://develop.svn.wordpress.org/trunk@42000


git-svn-id: http://core.svn.wordpress.org/trunk@41834 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api.php

@@ -1106,13 +1106,13 @@ function rest_validate_value_from_schema( $value, $args, $param = '' ) {
 		}
 
 		foreach ( $value as $property => $v ) {
-			if ( ! isset( $args['properties'][ $property ] ) ) {
-				continue;
-			}
-			$is_valid = rest_validate_value_from_schema( $v, $args['properties'][ $property ], $param . '[' . $property . ']' );
-
-			if ( is_wp_error( $is_valid ) ) {
-				return $is_valid;
+			if ( isset( $args['properties'][ $property ] ) ) {
+				$is_valid = rest_validate_value_from_schema( $v, $args['properties'][ $property ], $param . '[' . $property . ']' );
+				if ( is_wp_error( $is_valid ) ) {
+					return $is_valid;
+				}
+			} elseif ( isset( $args['additionalProperties'] ) && false === $args['additionalProperties'] ) {
+				return new WP_Error( 'rest_invalid_param', sprintf( __( '%1$s is not a valid property of Object.' ), $property ) );
 			}
 		}
 	}
@@ -1246,11 +1246,11 @@ function rest_sanitize_value_from_schema( $value, $args ) {
 		}
 
 		foreach ( $value as $property => $v ) {
-			if ( ! isset( $args['properties'][ $property ] ) ) {
+			if ( isset( $args['properties'][ $property ] ) ) {
+				$value[ $property ] = rest_sanitize_value_from_schema( $v, $args['properties'][ $property ] );
+			} elseif ( isset( $args['additionalProperties'] ) && false === $args['additionalProperties'] ) {
 				unset( $value[ $property ] );
-				continue;
 			}
-			$value[ $property ] = rest_sanitize_value_from_schema( $v, $args['properties'][ $property ] );
 		}
 
 		return $value;

wp-includes/rest-api/endpoints/class-wp-rest-controller.php

@@ -545,7 +545,7 @@ abstract class WP_REST_Controller {
 				$endpoint_args[ $field_id ]['required'] = true;
 			}
 
-			foreach ( array( 'type', 'format', 'enum', 'items', 'properties' ) as $schema_prop ) {
+			foreach ( array( 'type', 'format', 'enum', 'items', 'properties', 'additionalProperties' ) as $schema_prop ) {
 				if ( isset( $params[ $schema_prop ] ) ) {
 					$endpoint_args[ $field_id ][ $schema_prop ] = $params[ $schema_prop ];
 				}

wp-includes/rest-api/endpoints/class-wp-rest-settings-controller.php

@@ -248,6 +248,8 @@ class WP_REST_Settings_Controller extends WP_REST_Controller {
 				continue;
 			}
 
+			$rest_args['schema'] = $this->set_additional_properties_to_false( $rest_args['schema'] );
+
 			$rest_options[ $rest_args['name'] ] = $rest_args;
 		}
 
@@ -301,4 +303,32 @@ class WP_REST_Settings_Controller extends WP_REST_Controller {
 		}
 		return rest_parse_request_arg( $value, $request, $param );
 	}
+
+	/**
+	 * Recursively add additionalProperties = false to all objects in a schema.
+	 *
+	 * This is need to restrict properties of objects in settings values to only
+	 * registered items, as the REST API will allow additional properties by
+	 * default.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param array $schema The schema array.
+	 * @return array
+	 */
+	protected function set_additional_properties_to_false( $schema ) {
+		switch ( $schema['type'] ) {
+			case 'object':
+				foreach ( $schema['properties'] as $key => $child_schema ) {
+					$schema['properties'][ $key ] = $this->set_additional_properties_to_false( $child_schema );
+				}
+				$schema['additionalProperties'] = false;
+				break;
+			case 'array':
+				$schema['items'] = $this->set_additional_properties_to_false( $schema['items'] );
+				break;
+		}
+
+		return $schema;
+	}
 }

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-beta3-41999';
+$wp_version = '4.9-beta3-42000';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.