| @@ -1,17 +1,15 @@ | ||
| 1 | 1 | <?php |
| 2 | -/** | |
| 3 | - * Server REST-Class file. | |
| 4 | - * | |
| 5 | - * @package Activitypub | |
| 6 | - */ | |
| 7 | - | |
| 8 | 2 | namespace Activitypub\Rest; |
| 9 | 3 | |
| 4 | +use stdClass; | |
| 5 | +use WP_Error; | |
| 6 | +use WP_REST_Response; | |
| 10 | 7 | use Activitypub\Signature; |
| 8 | +use Activitypub\Model\Application; | |
| 11 | 9 | |
| 12 | 10 | /** |
| 13 | - * ActivityPub Server REST-Class. | |
| 11 | + * ActivityPub Server REST-Class | |
| 14 | 12 | * |
| 15 | 13 | * @author Django Doucet |
| 16 | 14 | * |
| 17 | 15 | * @see https://www.w3.org/TR/activitypub/#security-verification |
| @@ -17,286 +15,113 @@ | ||
| 17 | 15 | * @see https://www.w3.org/TR/activitypub/#security-verification |
| 18 | 16 | */ |
| 19 | 17 | class Server { |
| 20 | 18 | /** |
| 21 | - * Initialize the class, registering WordPress hooks. | |
| 19 | + * Initialize the class, registering WordPress hooks | |
| 22 | 20 | */ |
| 23 | 21 | public static function init() { |
| 24 | - \add_filter( 'rest_pre_dispatch', array( self::class, 'maybe_add_actor_from_signature' ), 10, 3 ); | |
| 25 | - \add_filter( 'rest_request_before_callbacks', array( self::class, 'validate_requests' ), 9, 3 ); | |
| 26 | - \add_filter( 'rest_request_parameter_order', array( self::class, 'request_parameter_order' ), 10, 2 ); | |
| 22 | + self::register_routes(); | |
| 27 | 23 | |
| 28 | - \add_filter( 'rest_post_dispatch', array( self::class, 'filter_output' ), 10, 3 ); | |
| 29 | - \add_filter( 'rest_post_dispatch', array( self::class, 'add_cors_headers' ), 10, 3 ); | |
| 30 | - \add_filter( 'rest_allowed_cors_headers', array( self::class, 'allow_cors_headers' ), 10, 2 ); | |
| 24 | + \add_filter( 'rest_request_before_callbacks', array( self::class, 'authorize_activitypub_requests' ), 10, 3 ); | |
| 31 | 25 | } |
| 32 | 26 | |
| 33 | 27 | /** |
| 34 | - * Callback function to validate incoming ActivityPub requests | |
| 35 | - * | |
| 36 | - * @param \WP_REST_Response|\WP_HTTP_Response|\WP_Error|mixed $response Result to send to the client. | |
| 37 | - * Usually a WP_REST_Response or WP_Error. | |
| 38 | - * @param array $handler Route handler used for the request. | |
| 39 | - * @param \WP_REST_Request $request Request used to generate the response. | |
| 40 | - * | |
| 41 | - * @return mixed|\WP_Error The response, error, or modified response. | |
| 28 | + * Register routes | |
| 42 | 29 | */ |
| 43 | - public static function validate_requests( $response, $handler, $request ) { | |
| 44 | - if ( 'HEAD' === $request->get_method() ) { | |
| 45 | - return $response; | |
| 46 | - } | |
| 47 | - | |
| 48 | - $route = $request->get_route(); | |
| 49 | - | |
| 50 | - if ( | |
| 51 | - \is_wp_error( $response ) || | |
| 52 | - ! \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE ) | |
| 53 | - ) { | |
| 54 | - return $response; | |
| 55 | - } | |
| 56 | - | |
| 57 | - $params = $request->get_json_params(); | |
| 58 | - | |
| 59 | - // Type is required for ActivityPub requests, so it fail later in the process. | |
| 60 | - if ( ! isset( $params['type'] ) ) { | |
| 61 | - return $response; | |
| 62 | - } | |
| 63 | - | |
| 64 | - if ( | |
| 65 | - ACTIVITYPUB_DISABLE_INCOMING_INTERACTIONS && | |
| 66 | - in_array( $params['type'], array( 'Create', 'Like', 'Announce' ), true ) | |
| 67 | - ) { | |
| 68 | - return new \WP_Error( | |
| 69 | - 'activitypub_server_does_not_accept_incoming_interactions', | |
| 70 | - \__( 'This server does not accept incoming interactions.', 'activitypub' ), | |
| 71 | - // We have to use a 2XX status code here, because otherwise the response will be | |
| 72 | - // treated as an error and Mastodon might block this WordPress instance. | |
| 73 | - array( 'status' => 202 ) | |
| 74 | - ); | |
| 75 | - } | |
| 76 | - | |
| 77 | - return $response; | |
| 30 | + public static function register_routes() { | |
| 31 | + \register_rest_route( | |
| 32 | + ACTIVITYPUB_REST_NAMESPACE, | |
| 33 | + '/application', | |
| 34 | + array( | |
| 35 | + array( | |
| 36 | + 'methods' => \WP_REST_Server::READABLE, | |
| 37 | + 'callback' => array( self::class, 'application_actor' ), | |
| 38 | + 'permission_callback' => '__return_true', | |
| 39 | + ), | |
| 40 | + ) | |
| 41 | + ); | |
| 78 | 42 | } |
| 79 | 43 | |
| 80 | 44 | /** |
| 81 | - * Modify the parameter priority order for a REST API request. | |
| 45 | + * Render Application actor profile | |
| 82 | 46 | * |
| 83 | - * @param string[] $order Array of types to check, in order of priority. | |
| 84 | - * @param \WP_REST_Request $request The request object. | |
| 85 | - * | |
| 86 | - * @return string[] The modified order of types to check. | |
| 47 | + * @return WP_REST_Response The JSON profile of the Application Actor. | |
| 87 | 48 | */ |
| 88 | - public static function request_parameter_order( $order, $request ) { | |
| 89 | - $route = $request->get_route(); | |
| 49 | + public static function application_actor() { | |
| 50 | + $user = new Application(); | |
| 90 | 51 | |
| 91 | - // Check if it is an activitypub request and exclude webfinger and nodeinfo endpoints. | |
| 92 | - if ( ! \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE ) ) { | |
| 93 | - return $order; | |
| 94 | - } | |
| 52 | + $json = $user->to_array(); | |
| 95 | 53 | |
| 96 | - $method = $request->get_method(); | |
| 54 | + $rest_response = new WP_REST_Response( $json, 200 ); | |
| 55 | + $rest_response->header( 'Content-Type', 'application/activity+json; charset=' . get_option( 'blog_charset' ) ); | |
| 97 | 56 | |
| 98 | - if ( \WP_REST_Server::CREATABLE !== $method ) { | |
| 99 | - return $order; | |
| 100 | - } | |
| 101 | - | |
| 102 | - return array( | |
| 103 | - 'JSON', | |
| 104 | - 'POST', | |
| 105 | - 'URL', | |
| 106 | - 'defaults', | |
| 107 | - ); | |
| 57 | + return $rest_response; | |
| 108 | 58 | } |
| 109 | 59 | |
| 110 | 60 | /** |
| 111 | - * Backfill a missing `actor` on incoming FeatureRequest activities from the signature. | |
| 61 | + * Callback function to authorize each api requests | |
| 112 | 62 | * |
| 113 | - * Mastodon (FEP-7aa9) omits `actor` from the FeatureRequest body and conveys the | |
| 114 | - * requesting actor only through the HTTP signature keyId. Our inbox routes require | |
| 115 | - * `actor`, so such a request is rejected during parameter validation before it can | |
| 116 | - * reach the inbox or its handler, which is why no Accept is ever sent. | |
| 63 | + * @see WP_REST_Request | |
| 117 | 64 | * |
| 118 | - * Derive the actor from the keyId and add it as a request parameter. The actor is | |
| 119 | - * injected with `set_param()` rather than by rewriting the request body, so the raw | |
| 120 | - * body stays byte-identical and the signed `Digest` still verifies. Inbox POSTs read | |
| 121 | - * JSON parameters first (see `request_parameter_order()`), so the value is visible to | |
| 122 | - * both parameter validation and the handler via `get_json_params()`. | |
| 65 | + * @see https://www.w3.org/wiki/SocialCG/ActivityPub/Primer/Authentication_Authorization#Authorized_fetch | |
| 66 | + * @see https://swicg.github.io/activitypub-http-signature/#authorized-fetch | |
| 123 | 67 | * |
| 124 | - * Scoped to FeatureRequest, the only activity type known to address this way. Runs on | |
| 125 | - * `rest_pre_dispatch` because that is the only hook that fires before required-parameter | |
| 126 | - * validation. Signature verification still runs afterwards and remains authoritative: | |
| 127 | - * the injected actor is derived from the very keyId the signature is checked against, so | |
| 128 | - * it cannot be used to impersonate another actor. | |
| 68 | + * @param WP_REST_Response|WP_HTTP_Response|WP_Error|mixed $response Result to send to the client. | |
| 69 | + * Usually a WP_REST_Response or WP_Error. | |
| 70 | + * @param array $handler Route handler used for the request. | |
| 71 | + * @param WP_REST_Request $request Request used to generate the response. | |
| 129 | 72 | * |
| 130 | - * @since 9.0.0 | |
| 131 | - * | |
| 132 | - * @param mixed $result Response to replace the request with, or null to continue. | |
| 133 | - * @param \WP_REST_Server $server Server instance. | |
| 134 | - * @param \WP_REST_Request $request The request object. | |
| 135 | - * | |
| 136 | - * @return mixed The unmodified `$result`. | |
| 73 | + * @return mixed|WP_Error The response, error, or modified response. | |
| 137 | 74 | */ |
| 138 | - public static function maybe_add_actor_from_signature( $result, $server, $request ) { | |
| 139 | - // Respect an earlier short-circuit. | |
| 140 | - if ( null !== $result ) { | |
| 141 | - return $result; | |
| 75 | + public static function authorize_activitypub_requests( $response, $handler, $request ) { | |
| 76 | + if ( 'HEAD' === $request->get_method() ) { | |
| 77 | + return $response; | |
| 142 | 78 | } |
| 143 | 79 | |
| 144 | - if ( \WP_REST_Server::CREATABLE !== $request->get_method() ) { | |
| 145 | - return $result; | |
| 146 | - } | |
| 80 | + $route = $request->get_route(); | |
| 147 | 81 | |
| 148 | - $route = $request->get_route(); | |
| 82 | + // check if it is an activitypub request and exclude webfinger and nodeinfo endpoints | |
| 149 | 83 | if ( |
| 150 | 84 | ! \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE ) || |
| 151 | - ! \str_ends_with( $route, '/inbox' ) | |
| 85 | + \str_starts_with( $route, '/' . \trailingslashit( ACTIVITYPUB_REST_NAMESPACE ) . 'webfinger' ) || | |
| 86 | + \str_starts_with( $route, '/' . \trailingslashit( ACTIVITYPUB_REST_NAMESPACE ) . 'nodeinfo' ) || | |
| 87 | + \str_starts_with( $route, '/' . \trailingslashit( ACTIVITYPUB_REST_NAMESPACE ) . 'application' ) | |
| 152 | 88 | ) { |
| 153 | - return $result; | |
| 154 | - } | |
| 155 | - | |
| 156 | - $json = $request->get_json_params(); | |
| 157 | - if ( ! \is_array( $json ) || 'FeatureRequest' !== ( $json['type'] ?? '' ) || ! empty( $json['actor'] ) ) { | |
| 158 | - return $result; | |
| 159 | - } | |
| 160 | - | |
| 161 | - $key_id = Signature::get_key_id( $request ); | |
| 162 | - if ( ! $key_id ) { | |
| 163 | - return $result; | |
| 164 | - } | |
| 165 | - | |
| 166 | - $request->set_param( 'actor', \strip_fragment_from_url( $key_id ) ); | |
| 167 | - | |
| 168 | - return $result; | |
| 169 | - } | |
| 170 | - | |
| 171 | - /** | |
| 172 | - * Filters the REST API response to properly handle the ActivityPub error formatting. | |
| 173 | - * | |
| 174 | - * @see https://codeberg.org/fediverse/fep/src/branch/main/fep/c180/fep-c180.md | |
| 175 | - * | |
| 176 | - * @param \WP_HTTP_Response $response Result to send to the client. Usually a `WP_REST_Response`. | |
| 177 | - * @param \WP_REST_Server $server Server instance. | |
| 178 | - * @param \WP_REST_Request $request Request used to generate the response. | |
| 179 | - * | |
| 180 | - * @return \WP_HTTP_Response The filtered response. | |
| 181 | - */ | |
| 182 | - public static function filter_output( $response, $server, $request ) { | |
| 183 | - $route = $request->get_route(); | |
| 184 | - | |
| 185 | - // Check if it is an activitypub request and exclude webfinger and nodeinfo endpoints. | |
| 186 | - if ( ! \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE ) ) { | |
| 187 | 89 | return $response; |
| 188 | 90 | } |
| 189 | 91 | |
| 190 | - // Exclude OAuth endpoints - they have their own error format per RFC 6749. | |
| 191 | - if ( \str_starts_with( $route, '/' . ACTIVITYPUB_REST_NAMESPACE . '/oauth' ) ) { | |
| 192 | - return $response; | |
| 193 | - } | |
| 92 | + /** | |
| 93 | + * Filter to defer signature verification | |
| 94 | + * | |
| 95 | + * Skip signature verification for debugging purposes or to reduce load for | |
| 96 | + * certain Activity-Types, like "Delete". | |
| 97 | + * | |
| 98 | + * @param bool $defer Whether to defer signature verification. | |
| 99 | + * @param WP_REST_Request $request The request used to generate the response. | |
| 100 | + * | |
| 101 | + * @return bool Whether to defer signature verification. | |
| 102 | + */ | |
| 103 | + $defer = \apply_filters( 'activitypub_defer_signature_verification', false, $request ); | |
| 194 | 104 | |
| 195 | - // Only alter responses that return an error status code. | |
| 196 | - if ( $response->get_status() < 400 ) { | |
| 105 | + if ( $defer ) { | |
| 197 | 106 | return $response; |
| 198 | 107 | } |
| 199 | 108 | |
| 200 | - $data = $response->get_data(); | |
| 201 | - | |
| 202 | - // Ensure that `$data` was already converted to a response. | |
| 203 | - if ( \is_wp_error( $data ) ) { | |
| 204 | - $response = \rest_convert_error_to_response( $data ); | |
| 205 | - $data = $response->get_data(); | |
| 109 | + if ( | |
| 110 | + // POST-Requests are always signed | |
| 111 | + 'GET' !== $request->get_method() || | |
| 112 | + // GET-Requests only require a signature in secure mode | |
| 113 | + ( 'GET' === $request->get_method() && ACTIVITYPUB_AUTHORIZED_FETCH ) | |
| 114 | + ) { | |
| 115 | + $verified_request = Signature::verify_http_signature( $request ); | |
| 116 | + if ( \is_wp_error( $verified_request ) ) { | |
| 117 | + return new WP_Error( | |
| 118 | + 'activitypub_signature_verification', | |
| 119 | + $verified_request->get_error_message(), | |
| 120 | + array( 'status' => 401 ) | |
| 121 | + ); | |
| 122 | + } | |
| 206 | 123 | } |
| 207 | 124 | |
| 208 | - $error = array( | |
| 209 | - 'type' => 'about:blank', | |
| 210 | - 'title' => $data['code'] ?? '', | |
| 211 | - 'detail' => $data['message'] ?? '', | |
| 212 | - 'status' => $response->get_status(), | |
| 213 | - | |
| 214 | - /* | |
| 215 | - * Provides the unstructured error data. | |
| 216 | - * | |
| 217 | - * @see https://nodeinfo.diaspora.software/schema.html#metadata. | |
| 218 | - */ | |
| 219 | - 'metadata' => $data, | |
| 220 | - ); | |
| 221 | - | |
| 222 | - $response->set_data( $error ); | |
| 223 | - | |
| 224 | 125 | return $response; |
| 225 | - } | |
| 226 | - | |
| 227 | - /** | |
| 228 | - * Add CORS headers to ActivityPub REST responses. | |
| 229 | - * | |
| 230 | - * @param \WP_REST_Response $response The REST response. | |
| 231 | - * @param \WP_REST_Server $server The REST server instance. | |
| 232 | - * @param \WP_REST_Request $request The request object. | |
| 233 | - * | |
| 234 | - * @return \WP_REST_Response The modified response. | |
| 235 | - */ | |
| 236 | - public static function add_cors_headers( $response, $server, $request ) { | |
| 237 | - $route = $request->get_route(); | |
| 238 | - $namespace = '/' . ACTIVITYPUB_REST_NAMESPACE; | |
| 239 | - | |
| 240 | - // Only add CORS to ActivityPub endpoints, except the interactive OAuth authorize endpoint. | |
| 241 | - if ( ! \str_starts_with( $route, $namespace ) || \str_starts_with( $route, $namespace . '/oauth/authorize' ) ) { | |
| 242 | - return $response; | |
| 243 | - } | |
| 244 | - | |
| 245 | - /* | |
| 246 | - * ActivityPub data is meant to be publicly readable by federation peers | |
| 247 | - * and browser-side clients. We do not enable credentialed cross-origin | |
| 248 | - * access: cookie auth would still be rejected by WordPress core's | |
| 249 | - * REST nonce check, and OAuth Bearer tokens travel in the | |
| 250 | - * Authorization header — which is permitted via Allow-Headers and | |
| 251 | - * does not require Allow-Credentials. | |
| 252 | - * | |
| 253 | - * Allow-Headers is contributed by core (which already lists `X-WP-Nonce`, | |
| 254 | - * `Authorization`, `Content-Type`, `Content-Disposition`, and `Content-MD5`) | |
| 255 | - * and extended for ActivityPub via the `rest_allowed_cors_headers` filter | |
| 256 | - * in self::allow_cors_headers(). | |
| 257 | - */ | |
| 258 | - $response->header( 'Access-Control-Allow-Origin', '*' ); | |
| 259 | - $response->header( 'Access-Control-Allow-Methods', 'GET, POST, OPTIONS' ); | |
| 260 | - | |
| 261 | - return $response; | |
| 262 | - } | |
| 263 | - | |
| 264 | - /** | |
| 265 | - * Extend the CORS Allow-Headers list for ActivityPub REST endpoints. | |
| 266 | - * | |
| 267 | - * Adds the headers ActivityPub clients need on top of WordPress core's | |
| 268 | - * defaults: `Accept` for content negotiation and `Last-Event-ID` for | |
| 269 | - * Server-Sent Events resume. | |
| 270 | - * | |
| 271 | - * @since 8.3.0 | |
| 272 | - * | |
| 273 | - * @param string[] $allow_headers Headers core currently permits in CORS requests. | |
| 274 | - * @param \WP_REST_Request $request The current REST request. | |
| 275 | - * | |
| 276 | - * @return string[] The (possibly extended) list of allowed headers. | |
| 277 | - */ | |
| 278 | - public static function allow_cors_headers( $allow_headers, $request ) { | |
| 279 | - $route = $request->get_route(); | |
| 280 | - $namespace = '/' . ACTIVITYPUB_REST_NAMESPACE; | |
| 281 | - | |
| 282 | - if ( ! \str_starts_with( $route, $namespace ) || \str_starts_with( $route, $namespace . '/oauth/authorize' ) ) { | |
| 283 | - return $allow_headers; | |
| 284 | - } | |
| 285 | - | |
| 286 | - return \array_values( \array_unique( \array_merge( (array) $allow_headers, array( 'Accept', 'Last-Event-ID' ) ) ) ); | |
| 287 | - } | |
| 288 | - | |
| 289 | - /** | |
| 290 | - * Send CORS headers directly via header(). | |
| 291 | - * | |
| 292 | - * Use this for endpoints that bypass the REST response flow | |
| 293 | - * (e.g. SSE streams that call exit() instead of returning a WP_REST_Response). | |
| 294 | - * | |
| 295 | - * @since 8.1.0 | |
| 296 | - */ | |
| 297 | - public static function send_cors_headers() { | |
| 298 | - \header( 'Access-Control-Allow-Origin: *' ); | |
| 299 | - \header( 'Access-Control-Allow-Methods: GET, POST, OPTIONS' ); | |
| 300 | - \header( 'Access-Control-Allow-Headers: Authorization, X-WP-Nonce, Content-Disposition, Content-MD5, Content-Type, Accept, Last-Event-ID' ); | |
| 301 | 126 | } |
| 302 | 127 | } |
