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1 | <?php declare(strict_types=1); |
2 | |
3 | namespace Taproot\IndieAuth; |
4 | |
5 | use BadMethodCallException; |
6 | use BarnabyWalters\Mf2 as M; |
7 | use Exception; |
8 | use GuzzleHttp\Psr7\Header as HeaderParser; |
9 | use IndieAuth\Client as IndieAuthClient; |
10 | use Mf2; |
11 | use Nyholm\Psr7\Response; |
12 | use PDO; |
13 | use Psr\Http\Client\ClientExceptionInterface; |
14 | use Psr\Http\Client\NetworkExceptionInterface; |
15 | use Psr\Http\Client\RequestExceptionInterface; |
16 | use Psr\Http\Message\ResponseInterface; |
17 | use Psr\Http\Message\ServerRequestInterface; |
18 | use Psr\Http\Server\MiddlewareInterface; |
19 | use Psr\Log\LoggerInterface; |
20 | use Psr\Log\NullLogger; |
21 | use Taproot\IndieAuth\Callback\AuthorizationFormInterface; |
22 | use Taproot\IndieAuth\Callback\DefaultAuthorizationForm; |
23 | use Taproot\IndieAuth\Storage\TokenStorageInterface; |
24 | |
25 | /** |
26 | * IndieAuth Server |
27 | * |
28 | * A PSR-7-compatible implementation of the request-handling logic for IndieAuth authorization endpoints |
29 | * and token endpoints. |
30 | * |
31 | * Typical minimal usage looks something like this: |
32 | * |
33 | * // Somewhere in your app set-up code: |
34 | * $server = new Taproot\IndieAuth\Server([ |
35 | * // A secret key, >= 64 characters long. |
36 | * 'secret' => YOUR_APP_INDIEAUTH_SECRET, |
37 | * |
38 | * // A path to store token data, or an object implementing TokenStorageInterface. |
39 | * 'tokenStorage' => '/../data/auth_tokens/', |
40 | * |
41 | * // An authentication callback function, which either returns data about the current user, |
42 | * // or redirects to/implements an authentication flow. |
43 | * 'authenticationHandler' => function (ServerRequestInterface $request, string $authenticationRedirect, ?string $normalizedMeUrl) { |
44 | * // If the request is authenticated, return an array with a `me` key containing the |
45 | * // canonical URL of the currently logged-in user. |
46 | * if ($userUrl = getLoggedInUserUrl($request)) { |
47 | * return ['me' => $userUrl]; |
48 | * } |
49 | * |
50 | * // Otherwise, redirect the user to a login page, ensuring that they will be redirected |
51 | * // back to the IndieAuth flow with query parameters intact once logged in. |
52 | * return new Response('302', ['Location' => 'https://example.com/login?next=' . urlencode($authenticationRedirect)]); |
53 | * } |
54 | * ]); |
55 | * |
56 | * // In your authorization endpoint route: |
57 | * return $server->handleAuthorizationEndpointRequest($request); |
58 | * |
59 | * // In your token endpoint route: |
60 | * return $server->handleTokenEndpointRequest($request); |
61 | * |
62 | * // In another route (e.g. a micropub route), to authenticate the request: |
63 | * // (assuming $bearerToken is a token parsed from an “Authorization: Bearer XXXXXX” header |
64 | * // or access_token property from a request body) |
65 | * if ($accessToken = $server->getTokenStorage()->getAccessToken($bearerToken)) { |
66 | * // Request is authenticated as $accessToken['me'], and is allowed to |
67 | * // act according to the scopes listed in $accessToken['scope']. |
68 | * $scopes = explode(' ', $accessToken['scope']); |
69 | * } |
70 | * |
71 | * Refer to the `__construct` documentation for further configuration options, and to the |
72 | * documentation for both handling methods for further documentation about them. |
73 | * |
74 | * @link https://indieauth.spec.indieweb.org/ |
75 | * @link https://www.rfc-editor.org/rfc/rfc6749.html#section-5.2 |
76 | * @link https://github.com/indieweb/indieauth-client-php |
77 | * @link https://github.com/Zegnat/php-mindee/blob/development/index.php |
78 | */ |
79 | class Server { |
80 | const HANDLE_NON_INDIEAUTH_REQUEST = 'handleNonIndieAuthRequestCallback'; |
81 | const HANDLE_AUTHENTICATION_REQUEST = 'authenticationHandler'; |
82 | |
83 | /** |
84 | * The query string parameter key used for storing the hash used for validating authorization request parameters. |
85 | */ |
86 | const HASH_QUERY_STRING_KEY = 'taproot_indieauth_server_hash'; |
87 | |
88 | /** |
89 | * The key used to store the CSRF token everywhere it’s used: Request parameters, Request body, and Cookies. |
90 | */ |
91 | const DEFAULT_CSRF_KEY = 'taproot_indieauth_server_csrf'; |
92 | |
93 | /** |
94 | * The form data key used for identifying a request as an authorization (consent screen) form submissions. |
95 | */ |
96 | const APPROVE_ACTION_KEY = 'taproot_indieauth_action'; |
97 | |
98 | /** |
99 | * The form data value used for identifying a request as an authorization (consent screen) form submissions. |
100 | */ |
101 | const APPROVE_ACTION_VALUE = 'approve'; |
102 | |
103 | protected Storage\TokenStorageInterface $tokenStorage; |
104 | |
105 | protected AuthorizationFormInterface $authorizationForm; |
106 | |
107 | protected MiddlewareInterface $csrfMiddleware; |
108 | |
109 | protected LoggerInterface $logger; |
110 | |
111 | /** @var callable */ |
112 | protected $httpGetWithEffectiveUrl; |
113 | |
114 | /** @var callable */ |
115 | protected $handleAuthenticationRequestCallback; |
116 | |
117 | /** @var callable */ |
118 | protected $handleNonIndieAuthRequest; |
119 | |
120 | protected string $exceptionTemplatePath; |
121 | |
122 | protected string $secret; |
123 | |
124 | protected bool $requirePkce; |
125 | |
126 | /** |
127 | * Constructor |
128 | * |
129 | * Server instances are configured by passing a config array to the constructor. |
130 | * |
131 | * The following keys are required: |
132 | * |
133 | * * `authenticationHandler`: a callable with the signature |
134 | * `function (ServerRequestInterface $request, string $authenticationRedirect, ?string $normalizedMeUrl): array|ResponseInterface`. |
135 | * This function is called on IndieAuth authorization requests, after validating the query parameters. |
136 | * |
137 | * It should check to see if $request is authenticated, then: |
138 | * * If it is authenticated, return an array which MUST have a `me` key, mapping to the |
139 | * canonical URL of the currently logged-in user. It may additionally have a `profile` key. These |
140 | * keys will be stored in the authorization code and sent to the client, if successful. |
141 | * * If it is not authenticated, either present or redirect to an authentication flow. This flow MUST |
142 | * redirect the logged-in used back to `$authenticationRedirect`. |
143 | * |
144 | * If the request has a valid `me` parameter, the canonicalized version of it is passed as |
145 | * `$normalizedMeUrl`. Otherwise, this parameter is null. This parameter can optionally be used |
146 | * as a suggestion for which user to log in as in a multi-user authentication flow, but should NOT |
147 | * be considered valid data. |
148 | * |
149 | * If redirecting to an existing authentication flow, this callable can usually be implemented as a |
150 | * closure. The callable may also implement its own authentication logic. For an example, see |
151 | * `Callback\SingleUserPasswordAuthenticationCallback`. |
152 | * * `secret`: A cryptographically random string with a minimum length of 64 characters. Used |
153 | * to hash and subsequently verify request query parameters which get passed around. |
154 | * * `tokenStorage`: Either an object implementing `Storage\TokenStorageInterface`, or a string path, |
155 | * which will be passed to `Storage\FilesystemJsonStorage`. This object handles persisting authorization |
156 | * codes and access tokens, as well as implementation-specific parts of the exchange process which are |
157 | * out of the scope of the Server class (e.g. lifetimes and expiry). Refer to the `Storage\TokenStorageInterface` |
158 | * documentation for more details. |
159 | * |
160 | * The following keys may be required depending on which packages you have installed: |
161 | * |
162 | * * `httpGetWithEffectiveUrl`: must be a callable with the following signature: |
163 | * `function (string $url): array [ResponseInterface $response, string $effectiveUrl]`, where |
164 | * `$effectiveUrl` is the final URL after following any redirects (unfortunately, neither the PSR-7 |
165 | * Response nor the PSR-18 Client interfaces offer a standard way of getting this very important |
166 | * data, hence the unusual return signature). If `guzzlehttp/guzzle` is installed, this parameter |
167 | * will be created automatically. Otherwise, the user must provide their own callable. |
168 | * |
169 | * The following keys are optional: |
170 | * |
171 | * * `authorizationForm`: an instance of `AuthorizationFormInterface`. Defaults to `DefaultAuthorizationForm`. |
172 | * Refer to that implementation if you wish to replace the consent screen/scope choosing/authorization form. |
173 | * * `csrfMiddleware`: an instance of `MiddlewareInterface`, which will be used to CSRF-protect the |
174 | * user-facing authorization flow. By default an instance of `DoubleSubmitCookieCsrfMiddleware`. |
175 | * Refer to that implementation if you want to replace it with your own middleware — you will |
176 | * likely have to either make sure your middleware sets the same request attribute, or alter your |
177 | * templates accordingly. |
178 | * * `exceptionTemplatePath`: string, path to a template which will be used for displaying user-facing |
179 | * errors. Defaults to `../templates/default_exception_response.html.php`, refer to that if you wish |
180 | * to write your own template. |
181 | * * `handleNonIndieAuthRequestCallback`: A callback with the following signature: |
182 | * `function (ServerRequestInterface $request): ?ResponseInterface` which will be called if the |
183 | * authorization endpoint gets a request which is not identified as an IndieAuth request or authorization |
184 | * form submission request. You could use this to handle various requests e.g. client-side requests |
185 | * made by your authentication or authorization pages, if it’s not convenient to put them elsewhere. |
186 | * Returning `null` will result in a standard `invalid_request` error being returned. |
187 | * * `logger`: An instance of `LoggerInterface`. Will be used for internal logging, and will also be set |
188 | * as the logger for any objects passed in config which implement `LoggerAwareInterface`. |
189 | * |
190 | * @param array $config An array of configuration variables |
191 | * @return self |
192 | */ |
193 | public function __construct(array $config) { |
194 | $config = array_merge([ |
195 | 'csrfMiddleware' => new Middleware\DoubleSubmitCookieCsrfMiddleware(self::DEFAULT_CSRF_KEY), |
196 | 'logger' => null, |
197 | self::HANDLE_NON_INDIEAUTH_REQUEST => function (ServerRequestInterface $request) { return null; }, // Default to no-op. |
198 | 'tokenStorage' => null, |
199 | 'httpGetWithEffectiveUrl' => null, |
200 | 'authorizationForm' => new DefaultAuthorizationForm(), |
201 | 'exceptionTemplatePath' => __DIR__ . '/../templates/default_exception_response.html.php', |
202 | 'requirePKCE' => true, |
203 | ], $config); |
204 | |
205 | $this->requirePkce = $config['requirePKCE']; |
206 | |
207 | if (!is_string($config['exceptionTemplatePath'])) { |
208 | throw new BadMethodCallException("\$config['exceptionTemplatePath'] must be a string (path)."); |
209 | } |
210 | $this->exceptionTemplatePath = $config['exceptionTemplatePath']; |
211 | |
212 | $secret = $config['secret'] ?? ''; |
213 | if (!is_string($secret) || strlen($secret) < 64) { |
214 | throw new BadMethodCallException("\$config['secret'] must be a string with a minimum length of 64 characters."); |
215 | } |
216 | $this->secret = $secret; |
217 | |
218 | if (!is_null($config['logger']) && !$config['logger'] instanceof LoggerInterface) { |
219 | throw new BadMethodCallException("\$config['logger'] must be an instance of \\Psr\\Log\\LoggerInterface or null."); |
220 | } |
221 | $this->logger = $config['logger'] ?? new NullLogger(); |
222 | |
223 | if (!(array_key_exists(self::HANDLE_AUTHENTICATION_REQUEST, $config) and is_callable($config[self::HANDLE_AUTHENTICATION_REQUEST]))) { |
224 | throw new BadMethodCallException('$callbacks[\'' . self::HANDLE_AUTHENTICATION_REQUEST .'\'] must be present and callable.'); |
225 | } |
226 | $this->handleAuthenticationRequestCallback = $config[self::HANDLE_AUTHENTICATION_REQUEST]; |
227 | |
228 | if (!is_callable($config[self::HANDLE_NON_INDIEAUTH_REQUEST])) { |
229 | throw new BadMethodCallException("\$config['" . self::HANDLE_NON_INDIEAUTH_REQUEST . "'] must be callable"); |
230 | } |
231 | $this->handleNonIndieAuthRequest = $config[self::HANDLE_NON_INDIEAUTH_REQUEST]; |
232 | |
233 | $tokenStorage = $config['tokenStorage']; |
234 | if (!$tokenStorage instanceof Storage\TokenStorageInterface) { |
235 | if (is_string($tokenStorage)) { |
236 | // Create a default access token storage with a TTL of 7 days. |
237 | $tokenStorage = new Storage\FilesystemJsonStorage($tokenStorage, $this->secret); |
238 | } else { |
239 | throw new BadMethodCallException("\$config['tokenStorage'] parameter must be either a string (path) or an instance of Taproot\IndieAuth\TokenStorageInterface."); |
240 | } |
241 | } |
242 | trySetLogger($tokenStorage, $this->logger); |
243 | $this->tokenStorage = $tokenStorage; |
244 | |
245 | $csrfMiddleware = $config['csrfMiddleware']; |
246 | if (!$csrfMiddleware instanceof MiddlewareInterface) { |
247 | throw new BadMethodCallException("\$config['csrfMiddleware'] must be null or implement MiddlewareInterface."); |
248 | } |
249 | trySetLogger($csrfMiddleware, $this->logger); |
250 | $this->csrfMiddleware = $csrfMiddleware; |
251 | |
252 | $httpGetWithEffectiveUrl = $config['httpGetWithEffectiveUrl']; |
253 | if (is_null($httpGetWithEffectiveUrl)) { |
254 | if (class_exists('\GuzzleHttp\Client')) { |
255 | $httpGetWithEffectiveUrl = function (string $uri): array { |
256 | // This code can’t be tested, ignore it for coverage purposes. |
257 | // @codeCoverageIgnoreStart |
258 | $resp = (new \GuzzleHttp\Client([ |
259 | \GuzzleHttp\RequestOptions::ALLOW_REDIRECTS => [ |
260 | 'max' => 10, |
261 | 'strict' => true, |
262 | 'referer' => true, |
263 | 'track_redirects' => true |
264 | ] |
265 | ]))->get($uri); |
266 | |
267 | $rdh = $resp->getHeader('X-Guzzle-Redirect-History'); |
268 | $effectiveUrl = empty($rdh) ? $uri : array_values($rdh)[count($rdh) - 1]; |
269 | |
270 | return [$resp, $effectiveUrl]; |
271 | }; |
272 | } else { |
273 | throw new BadMethodCallException("\$config['httpGetWithEffectiveUrl'] was not provided, and guzzlehttp/guzzle was not installed. Either require guzzlehttp/guzzle, or provide a valid callable."); |
274 | // @codeCoverageIgnoreEnd |
275 | } |
276 | } else { |
277 | if (!is_callable($httpGetWithEffectiveUrl)) { |
278 | throw new BadMethodCallException("\$config['httpGetWithEffectiveUrl'] must be callable."); |
279 | } |
280 | } |
281 | trySetLogger($httpGetWithEffectiveUrl, $this->logger); |
282 | $this->httpGetWithEffectiveUrl = $httpGetWithEffectiveUrl; |
283 | |
284 | if (!$config['authorizationForm'] instanceof AuthorizationFormInterface) { |
285 | throw new BadMethodCallException("When provided, \$config['authorizationForm'] must implement Taproot\IndieAuth\Callback\AuthorizationForm."); |
286 | } |
287 | $this->authorizationForm = $config['authorizationForm']; |
288 | trySetLogger($this->authorizationForm, $this->logger); |
289 | } |
290 | |
291 | public function getTokenStorage(): TokenStorageInterface { |
292 | return $this->tokenStorage; |
293 | } |
294 | |
295 | /** |
296 | * Handle Authorization Endpoint Request |
297 | * |
298 | * This method handles all requests to your authorization endpoint, passing execution off to |
299 | * other callbacks when necessary. The logical flow can be summarised as follows: |
300 | * |
301 | * * If this request an **auth code exchange for profile information**, validate the request |
302 | * and return a response or error response. |
303 | * * Otherwise, proceed, wrapping all execution in CSRF-protection middleware. |
304 | * * Validate the request’s indieauth authorization code request parameters, returning an |
305 | * error response if any are missing or invalid. |
306 | * * Call the authentication callback |
307 | * * If the callback returned an instance of ResponseInterface, the user is not currently |
308 | * logged in. Return the Response, which will presumably start an authentication flow. |
309 | * * Otherwise, the callback returned information about the currently logged-in user. Continue. |
310 | * * If this request is an authorization form submission, validate the data, store and authorization |
311 | * code and return a redirect response to the client redirect_uri with code data. On an error, return |
312 | * an appropriate error response. |
313 | * * Otherwise, fetch the client_id, parse app data if present, validate the `redirect_uri` and present |
314 | * the authorization form/consent screen to the user. |
315 | * * If none of the above apply, try calling the non-indieauth request handler. If it returns a Response, |
316 | * return that, otherwise return an error response. |
317 | * |
318 | * This route should NOT be wrapped in additional CSRF-protection, due to the need to handle API |
319 | * POST requests from the client. Make sure you call it from a route which is excluded from any |
320 | * CSRF-protection you might be using. To customise the CSRF protection used internally, refer to the |
321 | * `__construct` config array documentation for the `csrfMiddleware` key. |
322 | * |
323 | * Most user-facing errors are thrown as instances of `IndieAuthException`, which are passed off to |
324 | * `handleException` to be turned into an instance of `ResponseInterface`. If you want to customise |
325 | * error behaviour, one way to do so is to subclass `Server` and override that method. |
326 | * |
327 | * @param ServerRequestInterface $request |
328 | * @return ResponseInterface |
329 | */ |
330 | public function handleAuthorizationEndpointRequest(ServerRequestInterface $request): ResponseInterface { |
331 | $this->logger->info('Handling an IndieAuth Authorization Endpoint request.'); |
332 | |
333 | // If it’s a profile information request: |
334 | if (isIndieAuthAuthorizationCodeRedeemingRequest($request)) { |
335 | $this->logger->info('Handling a request to redeem an authorization code for profile information.'); |
336 | |
337 | $bodyParams = $request->getParsedBody(); |
338 | |
339 | if (!isset($bodyParams['code'])) { |
340 | $this->logger->warning('The exchange request was missing the code parameter. Returning an error response.'); |
341 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
342 | 'error' => 'invalid_request', |
343 | 'error_description' => 'The code parameter was missing.' |
344 | ])); |
345 | } |
346 | |
347 | // Attempt to internally exchange the provided auth code for an access token. |
348 | // We do this before anything else so that the auth code is invalidated as soon as the request starts, |
349 | // and the resulting access token is revoked if we encounter an error. This ends up providing a simpler |
350 | // and more flexible interface for TokenStorage implementors. |
351 | try { |
352 | // Call the token exchange method, passing in a callback which performs additional validation |
353 | // on the auth code before it gets exchanged. |
354 | $tokenData = $this->tokenStorage->exchangeAuthCodeForAccessToken($bodyParams['code'], function (array $authCode) use ($request, $bodyParams) { |
355 | // Verify that all required parameters are included. |
356 | $requiredParameters = ($this->requirePkce or !empty($authCode['code_challenge'])) ? ['client_id', 'redirect_uri', 'code_verifier'] : ['client_id', 'redirect_uri']; |
357 | $missingRequiredParameters = array_filter($requiredParameters, function ($p) use ($bodyParams) { |
358 | return !array_key_exists($p, $bodyParams) || empty($bodyParams[$p]); |
359 | }); |
360 | if (!empty($missingRequiredParameters)) { |
361 | $this->logger->warning('The exchange request was missing required parameters. Returning an error response.', ['missing' => $missingRequiredParameters]); |
362 | throw IndieAuthException::create(IndieAuthException::INVALID_REQUEST, $request); |
363 | } |
364 | |
365 | // Verify that it was issued for the same client_id and redirect_uri |
366 | if ($authCode['client_id'] !== $bodyParams['client_id'] |
367 | || $authCode['redirect_uri'] !== $bodyParams['redirect_uri']) { |
368 | $this->logger->error("The provided client_id and/or redirect_uri did not match those stored in the token."); |
369 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
370 | } |
371 | |
372 | // If the auth code was requested with no code_challenge, but the exchange request provides a |
373 | // code_verifier, return an error. |
374 | if (!empty($bodyParams['code_verifier']) && empty($authCode['code_challenge'])) { |
375 | $this->logger->error("A code_verifier was provided when trying to exchange an auth code requested without a code_challenge."); |
376 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
377 | } |
378 | |
379 | if ($this->requirePkce or !empty($authCode['code_challenge'])) { |
380 | // Check that the supplied code_verifier hashes to the stored code_challenge |
381 | // TODO: support method = plain as well as S256. |
382 | if (!hash_equals($authCode['code_challenge'], generatePKCECodeChallenge($bodyParams['code_verifier']))) { |
383 | $this->logger->error("The provided code_verifier did not hash to the stored code_challenge"); |
384 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
385 | } |
386 | } |
387 | |
388 | // Check that this token either grants at most the profile scope. |
389 | $requestedScopes = array_filter(explode(' ', $authCode['scope'] ?? '')); |
390 | if (!empty($requestedScopes) && $requestedScopes != ['profile']) { |
391 | $this->logger->error("An exchange request for a token granting scopes other than “profile” was sent to the authorization endpoint."); |
392 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
393 | } |
394 | }); |
395 | } catch (IndieAuthException $e) { |
396 | // If an exception was thrown, return a corresponding error response. |
397 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
398 | 'error' => $e->getInfo()['error'], |
399 | 'error_description' => $e->getMessage() |
400 | ])); |
401 | } |
402 | |
403 | if (is_null($tokenData)) { |
404 | $this->logger->error('Attempting to exchange an auth code for a token resulted in null.', $bodyParams); |
405 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
406 | 'error' => 'invalid_grant', |
407 | 'error_description' => 'The provided credentials were not valid.' |
408 | ])); |
409 | } |
410 | |
411 | // TODO: return an error if the token doesn’t contain a me key. |
412 | |
413 | // If everything checked out, return {"me": "https://example.com"} response |
414 | return new Response(200, [ |
415 | 'content-type' => 'application/json', |
416 | 'cache-control' => 'no-store', |
417 | ], json_encode(array_filter($tokenData, function (string $k) { |
418 | // Prevent codes exchanged at the authorization endpoint from returning any information other than |
419 | // me and profile. |
420 | return in_array($k, ['me', 'profile']); |
421 | }, ARRAY_FILTER_USE_KEY))); |
422 | } |
423 | |
424 | // Because the special case above isn’t allowed to be CSRF-protected, we have to do some rather silly |
425 | // closure gymnastics here to selectively-CSRF-protect requests which do need it. |
426 | return $this->csrfMiddleware->process($request, new Middleware\ClosureRequestHandler(function (ServerRequestInterface $request) { |
427 | // Wrap the entire user-facing handler in a try/catch block which catches any exception, converts it |
428 | // to IndieAuthException if necessary, then passes it to $this->handleException() to be turned into a |
429 | // response. |
430 | try { |
431 | $queryParams = $request->getQueryParams(); |
432 | |
433 | /** @var ResponseInterface|null $clientIdResponse */ |
434 | /** @var string|null $clientIdEffectiveUrl */ |
435 | /** @var array|null $clientIdMf2 */ |
436 | list($clientIdResponse, $clientIdEffectiveUrl, $clientIdMf2) = [null, null, null]; |
437 | |
438 | // If this is an authorization or approval request (allowing POST requests as well to accommodate |
439 | // approval requests and custom auth form submission. |
440 | if (isIndieAuthAuthorizationRequest($request, ['get', 'post'])) { |
441 | $this->logger->info('Handling an authorization request', ['method' => $request->getMethod()]); |
442 | |
443 | // Validate the Client ID. |
444 | if (!isset($queryParams['client_id']) || false === filter_var($queryParams['client_id'], FILTER_VALIDATE_URL) || !isClientIdentifier($queryParams['client_id'])) { |
445 | $this->logger->warning("The client_id provided in an authorization request was not valid.", $queryParams); |
446 | throw IndieAuthException::create(IndieAuthException::INVALID_CLIENT_ID, $request); |
447 | } |
448 | |
449 | // Validate the redirect URI. |
450 | if (!isset($queryParams['redirect_uri']) || false === filter_var($queryParams['redirect_uri'], FILTER_VALIDATE_URL)) { |
451 | $this->logger->warning("The client_id provided in an authorization request was not valid.", $queryParams); |
452 | throw IndieAuthException::create(IndieAuthException::INVALID_REDIRECT_URI, $request); |
453 | } |
454 | |
455 | // How most errors are handled depends on whether or not the request has a valid redirect_uri. In |
456 | // order to know that, we need to also validate, fetch and parse the client_id. |
457 | // If the request lacks a hash, or if the provided hash was invalid, perform the validation. |
458 | $currentRequestHash = hashAuthorizationRequestParameters($request, $this->secret, null, null, $this->requirePkce); |
459 | if (!isset($queryParams[self::HASH_QUERY_STRING_KEY]) or is_null($currentRequestHash) or !hash_equals($currentRequestHash, $queryParams[self::HASH_QUERY_STRING_KEY])) { |
460 | |
461 | // All we need to know at this stage is whether the redirect_uri is valid. If it |
462 | // sufficiently matches the client_id, we don’t (yet) need to fetch the client_id. |
463 | if (!urlComponentsMatch($queryParams['client_id'], $queryParams['redirect_uri'], [PHP_URL_SCHEME, PHP_URL_HOST, PHP_URL_PORT])) { |
464 | // If we do need to fetch the client_id, store the response and effective URL in variables |
465 | // we defined earlier, so they’re available to the approval request code path, which additionally |
466 | // needs to parse client_id for h-app markup. |
467 | try { |
468 | list($clientIdResponse, $clientIdEffectiveUrl) = call_user_func($this->httpGetWithEffectiveUrl, $queryParams['client_id']); |
469 | $clientIdMf2 = Mf2\parse((string) $clientIdResponse->getBody(), $clientIdEffectiveUrl); |
470 | } catch (ClientExceptionInterface | RequestExceptionInterface | NetworkExceptionInterface $e) { |
471 | $this->logger->error("Caught an HTTP exception while trying to fetch the client_id. Returning an error response.", [ |
472 | 'client_id' => $queryParams['client_id'], |
473 | 'exception' => $e->__toString() |
474 | ]); |
475 | |
476 | throw IndieAuthException::create(IndieAuthException::HTTP_EXCEPTION_FETCHING_CLIENT_ID, $request, $e); |
477 | } catch (Exception $e) { |
478 | $this->logger->error("Caught an unknown exception while trying to fetch the client_id. Returning an error response.", [ |
479 | 'exception' => $e->__toString() |
480 | ]); |
481 | |
482 | throw IndieAuthException::create(IndieAuthException::INTERNAL_EXCEPTION_FETCHING_CLIENT_ID, $request, $e); |
483 | } |
484 | |
485 | // Search for all link@rel=redirect_uri at the client_id. |
486 | $clientIdRedirectUris = []; |
487 | if (array_key_exists('redirect_uri', $clientIdMf2['rels'])) { |
488 | $clientIdRedirectUris = array_merge($clientIdRedirectUris, $clientIdMf2['rels']['redirect_uri']); |
489 | } |
490 | |
491 | foreach (HeaderParser::parse($clientIdResponse->getHeader('Link')) as $link) { |
492 | if (array_key_exists('rel', $link) && mb_strpos(" {$link['rel']} ", " redirect_uri ") !== false) { |
493 | // Strip off the < > which surround the link URL for some reason. |
494 | $clientIdRedirectUris[] = substr($link[0], 1, strlen($link[0]) - 2); |
495 | } |
496 | } |
497 | |
498 | // If the authority of the redirect_uri does not match the client_id, or exactly match one of their redirect URLs, return an error. |
499 | if (!in_array($queryParams['redirect_uri'], $clientIdRedirectUris)) { |
500 | $this->logger->warning("The provided redirect_uri did not match either the client_id, nor the discovered redirect URIs.", [ |
501 | 'provided_redirect_uri' => $queryParams['redirect_uri'], |
502 | 'provided_client_id' => $queryParams['client_id'], |
503 | 'discovered_redirect_uris' => $clientIdRedirectUris |
504 | ]); |
505 | |
506 | throw IndieAuthException::create(IndieAuthException::INVALID_REDIRECT_URI, $request); |
507 | } |
508 | } |
509 | } |
510 | |
511 | // From now on, we can assume that redirect_uri is valid. Any IndieAuth-related errors should be |
512 | // reported by redirecting to redirect_uri with error parameters. |
513 | |
514 | // Validate the state parameter. |
515 | if (!isset($queryParams['state']) or !isValidState($queryParams['state'])) { |
516 | $this->logger->warning("The state provided in an authorization request was not valid.", $queryParams); |
517 | throw IndieAuthException::create(IndieAuthException::INVALID_STATE, $request); |
518 | } |
519 | // From now on, any redirect error responses should include the state parameter. |
520 | // This is handled automatically in `handleException()` and is only noted here |
521 | // for reference. |
522 | |
523 | // If either PKCE parameter is present, validate both. |
524 | if (isset($queryParams['code_challenge']) or isset($queryParams['code_challenge_method'])) { |
525 | if (!isset($queryParams['code_challenge']) or !isValidCodeChallenge($queryParams['code_challenge'])) { |
526 | $this->logger->warning("The code_challenge provided in an authorization request was not valid.", $queryParams); |
527 | throw IndieAuthException::create(IndieAuthException::INVALID_CODE_CHALLENGE, $request); |
528 | } |
529 | |
530 | if (!isset($queryParams['code_challenge_method']) or !in_array($queryParams['code_challenge_method'], ['S256', 'plain'])) { |
531 | $this->logger->error("The code_challenge_method parameter was missing or invalid.", $queryParams); |
532 | throw IndieAuthException::create(IndieAuthException::INVALID_CODE_CHALLENGE, $request); |
533 | } |
534 | } else { |
535 | // If neither PKCE parameter is defined, and PKCE is required, throw an error. Otherwise, proceed. |
536 | if ($this->requirePkce) { |
537 | $this->logger->warning("PKCE is required, and both code_challenge and code_challenge_method were missing."); |
538 | throw IndieAuthException::create(IndieAuthException::INVALID_REQUEST_REDIRECT, $request); |
539 | } |
540 | } |
541 | |
542 | // Validate the scope parameter, if provided. |
543 | if (array_key_exists('scope', $queryParams) && !isValidScope($queryParams['scope'])) { |
544 | $this->logger->warning("The scope provided in an authorization request was not valid.", $queryParams); |
545 | throw IndieAuthException::create(IndieAuthException::INVALID_SCOPE, $request); |
546 | } |
547 | |
548 | // Normalise the me parameter, if it exists. |
549 | if (array_key_exists('me', $queryParams)) { |
550 | $queryParams['me'] = IndieAuthClient::normalizeMeURL($queryParams['me']); |
551 | // If the me parameter is not a valid profile URL, ignore it. |
552 | if (false === $queryParams['me'] || !isProfileUrl($queryParams['me'])) { |
553 | $queryParams['me'] = null; |
554 | } |
555 | } |
556 | |
557 | // Build a URL containing the indieauth authorization request parameters, hashing them |
558 | // to protect them from being changed. |
559 | // Make a hash of the protected indieauth-specific parameters. If PKCE is in use, include |
560 | // the PKCE parameters in the hash. Otherwise, leave them out. |
561 | $hash = hashAuthorizationRequestParameters($request, $this->secret, null, null, $this->requirePkce); |
562 | // Operate on a copy of $queryParams, otherwise requests will always have a valid hash! |
563 | $redirectQueryParams = $queryParams; |
564 | $redirectQueryParams[self::HASH_QUERY_STRING_KEY] = $hash; |
565 | $authenticationRedirect = $request->getUri()->withQuery(buildQueryString($redirectQueryParams))->__toString(); |
566 | |
567 | // User-facing requests always start by calling the authentication request callback. |
568 | $this->logger->info('Calling handle_authentication_request callback'); |
569 | $authenticationResult = call_user_func($this->handleAuthenticationRequestCallback, $request, $authenticationRedirect, $queryParams['me'] ?? null); |
570 | |
571 | // If the authentication handler returned a Response, return that as-is. |
572 | if ($authenticationResult instanceof ResponseInterface) { |
573 | return $authenticationResult; |
574 | } elseif (is_array($authenticationResult)) { |
575 | // Check the resulting array for errors. |
576 | if (!array_key_exists('me', $authenticationResult)) { |
577 | $this->logger->error('The handle_authentication_request callback returned an array with no me key.', ['array' => $authenticationResult]); |
578 | throw IndieAuthException::create(IndieAuthException::AUTHENTICATION_CALLBACK_MISSING_ME_PARAM, $request); |
579 | } |
580 | |
581 | // If this is a POST request sent from the authorization (i.e. scope-choosing) form: |
582 | if (isAuthorizationApprovalRequest($request)) { |
583 | // Authorization approval requests MUST include a hash protecting the sensitive IndieAuth |
584 | // authorization request parameters from being changed, e.g. by a malicious script which |
585 | // found its way onto the authorization form. |
586 | if (!array_key_exists(self::HASH_QUERY_STRING_KEY, $queryParams)) { |
587 | $this->logger->warning("An authorization approval request did not have a " . self::HASH_QUERY_STRING_KEY . " parameter."); |
588 | throw IndieAuthException::create(IndieAuthException::AUTHORIZATION_APPROVAL_REQUEST_MISSING_HASH, $request); |
589 | } |
590 | |
591 | $expectedHash = hashAuthorizationRequestParameters($request, $this->secret, null, null, $this->requirePkce); |
592 | if (!isset($queryParams[self::HASH_QUERY_STRING_KEY]) or is_null($expectedHash) or !hash_equals($expectedHash, $queryParams[self::HASH_QUERY_STRING_KEY])) { |
593 | $this->logger->warning("The hash provided in the URL was invalid!", [ |
594 | 'expected' => $expectedHash, |
595 | 'actual' => $queryParams[self::HASH_QUERY_STRING_KEY] |
596 | ]); |
597 | throw IndieAuthException::create(IndieAuthException::AUTHORIZATION_APPROVAL_REQUEST_INVALID_HASH, $request); |
598 | } |
599 | |
600 | // Assemble the data for the authorization code, store it somewhere persistent. |
601 | $code = array_merge($authenticationResult, [ |
602 | 'client_id' => $queryParams['client_id'], |
603 | 'redirect_uri' => $queryParams['redirect_uri'], |
604 | 'state' => $queryParams['state'], |
605 | 'code_challenge' => $queryParams['code_challenge'] ?? null, |
606 | 'code_challenge_method' => $queryParams['code_challenge_method'] ?? null, |
607 | 'requested_scope' => $queryParams['scope'] ?? '', |
608 | ]); |
609 | |
610 | // Pass it to the auth code customisation callback. |
611 | $code = $this->authorizationForm->transformAuthorizationCode($request, $code); |
612 | |
613 | // Store the authorization code. |
614 | $authCode = $this->tokenStorage->createAuthCode($code); |
615 | if (is_null($authCode)) { |
616 | // If saving the authorization code failed silently, there isn’t much we can do about it, |
617 | // but should at least log and return an error. |
618 | $this->logger->error("Saving the authorization code failed and returned false without raising an exception."); |
619 | throw IndieAuthException::create(IndieAuthException::INTERNAL_ERROR_REDIRECT, $request); |
620 | } |
621 | |
622 | // Return a redirect to the client app. |
623 | return new Response(302, [ |
624 | 'Location' => appendQueryParams($queryParams['redirect_uri'], [ |
625 | 'code' => $authCode, |
626 | 'state' => $code['state'] |
627 | ]), |
628 | 'Cache-control' => 'no-cache' |
629 | ]); |
630 | } |
631 | |
632 | // Otherwise, the user is authenticated and needs to authorize the client app + choose scopes. |
633 | |
634 | // Fetch the client_id URL to find information about the client to present to the user. |
635 | // TODO: in order to comply with https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.2.1, |
636 | // it may be necessary to do this before returning any other kind of error response, as, per |
637 | // the spec, errors should only be shown to the user if the client_id and redirect_uri parameters |
638 | // are missing or invalid. Otherwise, they should be sent back to the client with an error |
639 | // redirect response. |
640 | if (is_null($clientIdResponse) || is_null($clientIdEffectiveUrl) || is_null($clientIdMf2)) { |
641 | try { |
642 | /** @var ResponseInterface $clientIdResponse */ |
643 | list($clientIdResponse, $clientIdEffectiveUrl) = call_user_func($this->httpGetWithEffectiveUrl, $queryParams['client_id']); |
644 | $clientIdMf2 = Mf2\parse((string) $clientIdResponse->getBody(), $clientIdEffectiveUrl); |
645 | } catch (ClientExceptionInterface | RequestExceptionInterface | NetworkExceptionInterface $e) { |
646 | $this->logger->error("Caught an HTTP exception while trying to fetch the client_id. Returning an error response.", [ |
647 | 'client_id' => $queryParams['client_id'], |
648 | 'exception' => $e->__toString() |
649 | ]); |
650 | |
651 | // At this point in the flow, we’ve already guaranteed that the redirect_uri is valid, |
652 | // so in theory we should report these errors by redirecting there. |
653 | throw IndieAuthException::create(IndieAuthException::INTERNAL_ERROR_REDIRECT, $request, $e); |
654 | } catch (Exception $e) { |
655 | $this->logger->error("Caught an unknown exception while trying to fetch the client_id. Returning an error response.", [ |
656 | 'exception' => $e->__toString() |
657 | ]); |
658 | |
659 | throw IndieAuthException::create(IndieAuthException::INTERNAL_ERROR_REDIRECT, $request, $e); |
660 | } |
661 | } |
662 | |
663 | // Search for an h-app with u-url matching the client_id. |
664 | $clientHApps = M\findMicroformatsByProperty(M\findMicroformatsByType($clientIdMf2, 'h-app'), 'url', $queryParams['client_id']); |
665 | $clientHApp = empty($clientHApps) ? null : $clientHApps[0]; |
666 | |
667 | // Present the authorization UI. |
668 | return $this->authorizationForm->showForm($request, $authenticationResult, $authenticationRedirect, $clientHApp) |
669 | ->withAddedHeader('Cache-control', 'no-cache'); |
670 | } |
671 | } |
672 | |
673 | // If the request isn’t an IndieAuth Authorization or Code-redeeming request, it’s either an invalid |
674 | // request or something to do with a custom auth handler (e.g. sending a one-time code in an email.) |
675 | $nonIndieAuthRequestResult = call_user_func($this->handleNonIndieAuthRequest, $request); |
676 | if ($nonIndieAuthRequestResult instanceof ResponseInterface) { |
677 | return $nonIndieAuthRequestResult; |
678 | } else { |
679 | // In this code path we have not validated the redirect_uri, so show a regular error page |
680 | // rather than returning a redirect error. |
681 | throw IndieAuthException::create(IndieAuthException::INTERNAL_ERROR, $request); |
682 | } |
683 | } catch (IndieAuthException $e) { |
684 | // All IndieAuthExceptions will already have been logged. |
685 | return $this->handleException($e); |
686 | } catch (Exception $e) { |
687 | // Unknown exceptions will not have been logged; do so now. |
688 | $this->logger->error("Caught unknown exception: {$e}"); |
689 | return $this->handleException(IndieAuthException::create(0, $request, $e)); |
690 | } |
691 | })); |
692 | } |
693 | |
694 | /** |
695 | * Handle Token Endpoint Request |
696 | * |
697 | * Handles requests to the IndieAuth token endpoint. The logical flow can be summarised as follows: |
698 | * |
699 | * * Check that the request is a code redeeming request. Return an error if not. |
700 | * * Ensure that all required parameters are present. Return an error if not. |
701 | * * Attempt to exchange the `code` parameter for an access token. Return an error if it fails. |
702 | * * Make sure the client_id and redirect_uri request parameters match those stored in the auth code. If not, revoke the access token and return an error. |
703 | * * Make sure the provided code_verifier hashes to the code_challenge stored in the auth code. If not, revoke the access token and return an error. |
704 | * * Make sure the granted scope stored in the auth code is not empty. If it is, revoke the access token and return an error. |
705 | * * Otherwise, return a success response containing information about the issued access token. |
706 | * |
707 | * This method must NOT be CSRF-protected as it accepts external requests from client apps. |
708 | * |
709 | * @param ServerRequestInterface $request |
710 | * @return ResponseInterface |
711 | */ |
712 | public function handleTokenEndpointRequest(ServerRequestInterface $request): ResponseInterface { |
713 | if (isIndieAuthAuthorizationCodeRedeemingRequest($request)) { |
714 | $this->logger->info('Handling a request to redeem an authorization code for profile information.'); |
715 | |
716 | $bodyParams = $request->getParsedBody(); |
717 | |
718 | if (!isset($bodyParams['code'])) { |
719 | $this->logger->warning('The exchange request was missing the code parameter. Returning an error response.'); |
720 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
721 | 'error' => 'invalid_request', |
722 | 'error_description' => 'The code parameter was missing.' |
723 | ])); |
724 | } |
725 | |
726 | // Attempt to internally exchange the provided auth code for an access token. |
727 | // We do this before anything else so that the auth code is invalidated as soon as the request starts, |
728 | // and the resulting access token is revoked if we encounter an error. This ends up providing a simpler |
729 | // and more flexible interface for TokenStorage implementors. |
730 | try { |
731 | // Call the token exchange method, passing in a callback which performs additional validation |
732 | // on the auth code before it gets exchanged. |
733 | $tokenData = $this->tokenStorage->exchangeAuthCodeForAccessToken($bodyParams['code'], function (array $authCode) use ($request, $bodyParams) { |
734 | // Verify that all required parameters are included. |
735 | $requiredParameters = ($this->requirePkce or !empty($authCode['code_challenge'])) ? ['client_id', 'redirect_uri', 'code_verifier'] : ['client_id', 'redirect_uri']; |
736 | $missingRequiredParameters = array_filter($requiredParameters, function ($p) use ($bodyParams) { |
737 | return !array_key_exists($p, $bodyParams) || empty($bodyParams[$p]); |
738 | }); |
739 | if (!empty($missingRequiredParameters)) { |
740 | $this->logger->warning('The exchange request was missing required parameters. Returning an error response.', ['missing' => $missingRequiredParameters]); |
741 | throw IndieAuthException::create(IndieAuthException::INVALID_REQUEST, $request); |
742 | } |
743 | |
744 | // Verify that it was issued for the same client_id and redirect_uri |
745 | if ($authCode['client_id'] !== $bodyParams['client_id'] |
746 | || $authCode['redirect_uri'] !== $bodyParams['redirect_uri']) { |
747 | $this->logger->error("The provided client_id and/or redirect_uri did not match those stored in the token."); |
748 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
749 | } |
750 | |
751 | // If the auth code was requested with no code_challenge, but the exchange request provides a |
752 | // code_verifier, return an error. |
753 | if (!empty($bodyParams['code_verifier']) && empty($authCode['code_challenge'])) { |
754 | $this->logger->error("A code_verifier was provided when trying to exchange an auth code requested without a code_challenge."); |
755 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
756 | } |
757 | |
758 | if ($this->requirePkce or !empty($authCode['code_challenge'])) { |
759 | // Check that the supplied code_verifier hashes to the stored code_challenge |
760 | // TODO: support method = plain as well as S256. |
761 | if (!hash_equals($authCode['code_challenge'], generatePKCECodeChallenge($bodyParams['code_verifier']))) { |
762 | $this->logger->error("The provided code_verifier did not hash to the stored code_challenge"); |
763 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
764 | } |
765 | } |
766 | |
767 | // Check that scope is not empty. |
768 | if (empty($authCode['scope'])) { |
769 | $this->logger->error("An exchange request for a token with an empty scope was sent to the token endpoint."); |
770 | throw IndieAuthException::create(IndieAuthException::INVALID_GRANT, $request); |
771 | } |
772 | }); |
773 | } catch (IndieAuthException $e) { |
774 | // If an exception was thrown, return a corresponding error response. |
775 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
776 | 'error' => $e->getInfo()['error'], |
777 | 'error_description' => $e->getMessage() |
778 | ])); |
779 | } |
780 | |
781 | if (is_null($tokenData)) { |
782 | $this->logger->error('Attempting to exchange an auth code for a token resulted in null.', $bodyParams); |
783 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
784 | 'error' => 'invalid_grant', |
785 | 'error_description' => 'The provided credentials were not valid.' |
786 | ])); |
787 | } |
788 | |
789 | // TODO: return an error if the token doesn’t contain a me key. |
790 | |
791 | // If everything checked out, return {"me": "https://example.com"} response |
792 | return new Response(200, [ |
793 | 'content-type' => 'application/json', |
794 | 'cache-control' => 'no-store', |
795 | ], json_encode(array_merge([ |
796 | // Ensure that the token_type key is present, if tokenStorage doesn’t include it. |
797 | 'token_type' => 'Bearer' |
798 | ], array_filter($tokenData, function (string $k) { |
799 | // We should be able to trust the return data from tokenStorage, but there’s no harm in |
800 | // preventing code_challenges from leaking, per OAuth2. |
801 | return !in_array($k, ['code_challenge', 'code_challenge_method']); |
802 | }, ARRAY_FILTER_USE_KEY)))); |
803 | } |
804 | |
805 | return new Response(400, ['content-type' => 'application/json'], json_encode([ |
806 | 'error' => 'invalid_request', |
807 | 'error_description' => 'Request to token endpoint was not a valid code exchange request.' |
808 | ])); |
809 | } |
810 | |
811 | /** |
812 | * Handle Exception |
813 | * |
814 | * Turns an instance of `IndieAuthException` into an appropriate instance of `ResponseInterface`. |
815 | */ |
816 | protected function handleException(IndieAuthException $exception): ResponseInterface { |
817 | $exceptionData = $exception->getInfo(); |
818 | |
819 | if ($exceptionData['statusCode'] == 302) { |
820 | // This exception is handled by redirecting to the redirect_uri with error parameters. |
821 | $redirectQueryParams = [ |
822 | 'error' => $exceptionData['error'] ?? 'invalid_request', |
823 | 'error_description' => (string) $exception |
824 | ]; |
825 | |
826 | // If the state parameter was valid, include it in the error redirect. |
827 | if ($exception->getCode() !== IndieAuthException::INVALID_STATE) { |
828 | $redirectQueryParams['state'] = $exception->getRequest()->getQueryParams()['state']; |
829 | } |
830 | |
831 | return new Response($exceptionData['statusCode'], [ |
832 | 'Location' => appendQueryParams((string) $exception->getRequest()->getQueryParams()['redirect_uri'], $redirectQueryParams) |
833 | ]); |
834 | } else { |
835 | // This exception should be shown to the user. |
836 | return new Response($exception->getStatusCode(), ['content-type' => 'text/html'], renderTemplate($this->exceptionTemplatePath, [ |
837 | 'request' => $exception->getRequest(), |
838 | 'exception' => $exception |
839 | ])); |
840 | } |
841 | } |
842 | } |