extlib/Auth/OpenID/Server.php

   1 <?php
   2
   3 /**
   4  * OpenID server protocol and logic.
   5  *
   6  * Overview
   7  *
   8  * An OpenID server must perform three tasks:
   9  *
  10  *  1. Examine the incoming request to determine its nature and validity.
  11  *  2. Make a decision about how to respond to this request.
  12  *  3. Format the response according to the protocol.
  13  *
  14  * The first and last of these tasks may performed by the {@link
  15  * Auth_OpenID_Server::decodeRequest()} and {@link
  16  * Auth_OpenID_Server::encodeResponse} methods.  Who gets to do the
  17  * intermediate task -- deciding how to respond to the request -- will
  18  * depend on what type of request it is.
  19  *
  20  * If it's a request to authenticate a user (a 'checkid_setup' or
  21  * 'checkid_immediate' request), you need to decide if you will assert
  22  * that this user may claim the identity in question.  Exactly how you
  23  * do that is a matter of application policy, but it generally
  24  * involves making sure the user has an account with your system and
  25  * is logged in, checking to see if that identity is hers to claim,
  26  * and verifying with the user that she does consent to releasing that
  27  * information to the party making the request.
  28  *
  29  * Examine the properties of the {@link Auth_OpenID_CheckIDRequest}
  30  * object, and if and when you've come to a decision, form a response
  31  * by calling {@link Auth_OpenID_CheckIDRequest::answer()}.
  32  *
  33  * Other types of requests relate to establishing associations between
  34  * client and server and verifing the authenticity of previous
  35  * communications.  {@link Auth_OpenID_Server} contains all the logic
  36  * and data necessary to respond to such requests; just pass it to
  37  * {@link Auth_OpenID_Server::handleRequest()}.
  38  *
  39  * OpenID Extensions
  40  *
  41  * Do you want to provide other information for your users in addition
  42  * to authentication?  Version 1.2 of the OpenID protocol allows
  43  * consumers to add extensions to their requests.  For example, with
  44  * sites using the Simple Registration
  45  * Extension
  46  * (http://www.openidenabled.com/openid/simple-registration-extension/),
  47  * a user can agree to have their nickname and e-mail address sent to
  48  * a site when they sign up.
  49  *
  50  * Since extensions do not change the way OpenID authentication works,
  51  * code to handle extension requests may be completely separate from
  52  * the {@link Auth_OpenID_Request} class here.  But you'll likely want
  53  * data sent back by your extension to be signed.  {@link
  54  * Auth_OpenID_ServerResponse} provides methods with which you can add
  55  * data to it which can be signed with the other data in the OpenID
  56  * signature.
  57  *
  58  * For example:
  59  *
  60  * <pre>  // when request is a checkid_* request
  61  *  $response = $request->answer(true);
  62  *  // this will a signed 'openid.sreg.timezone' parameter to the response
  63  *  response.addField('sreg', 'timezone', 'America/Los_Angeles')</pre>
  64  *
  65  * Stores
  66  *
  67  * The OpenID server needs to maintain state between requests in order
  68  * to function.  Its mechanism for doing this is called a store.  The
  69  * store interface is defined in Interface.php.  Additionally, several
  70  * concrete store implementations are provided, so that most sites
  71  * won't need to implement a custom store.  For a store backed by flat
  72  * files on disk, see {@link Auth_OpenID_FileStore}.  For stores based
  73  * on MySQL, SQLite, or PostgreSQL, see the {@link
  74  * Auth_OpenID_SQLStore} subclasses.
  75  *
  76  * Upgrading
  77  *
  78  * The keys by which a server looks up associations in its store have
  79  * changed in version 1.2 of this library.  If your store has entries
  80  * created from version 1.0 code, you should empty it.
  81  *
  82  * PHP versions 4 and 5
  83  *
  84  * LICENSE: See the COPYING file included in this distribution.
  85  *
  86  * @package OpenID
  87  * @author JanRain, Inc. <openid@janrain.com>
  88  * @copyright 2005-2008 Janrain, Inc.
  89  * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
  90  */
  91
  92 /**
  93  * Required imports
  94  */
  95 require_once "Auth/OpenID.php";
  96 require_once "Auth/OpenID/Association.php";
  97 require_once "Auth/OpenID/CryptUtil.php";
  98 require_once "Auth/OpenID/BigMath.php";
  99 require_once "Auth/OpenID/DiffieHellman.php";
 100 require_once "Auth/OpenID/KVForm.php";
 101 require_once "Auth/OpenID/TrustRoot.php";
 102 require_once "Auth/OpenID/ServerRequest.php";
 103 require_once "Auth/OpenID/Message.php";
 104 require_once "Auth/OpenID/Nonce.php";
 105
 106 define('AUTH_OPENID_HTTP_OK', 200);
 107 define('AUTH_OPENID_HTTP_REDIRECT', 302);
 108 define('AUTH_OPENID_HTTP_ERROR', 400);
 109
 110 /**
 111  * @access private
 112  */
 113 global $_Auth_OpenID_Request_Modes;
 114 $_Auth_OpenID_Request_Modes = array('checkid_setup',
 115                                     'checkid_immediate');
 116
 117 /**
 118  * @access private
 119  */
 120 define('Auth_OpenID_ENCODE_KVFORM', 'kfvorm');
 121
 122 /**
 123  * @access private
 124  */
 125 define('Auth_OpenID_ENCODE_URL', 'URL/redirect');
 126
 127 /**
 128  * @access private
 129  */
 130 define('Auth_OpenID_ENCODE_HTML_FORM', 'HTML form');
 131
 132 /**
 133  * @access private
 134  */
 135 function Auth_OpenID_isError($obj, $cls = 'Auth_OpenID_ServerError')
 136 {
 137     return is_a($obj, $cls);
 138 }
 139
 140 /**
 141  * An error class which gets instantiated and returned whenever an
 142  * OpenID protocol error occurs.  Be prepared to use this in place of
 143  * an ordinary server response.
 144  *
 145  * @package OpenID
 146  */
 147 class Auth_OpenID_ServerError {
 148     /**
 149      * @access private
 150      */
 151     function Auth_OpenID_ServerError($message = null, $text = null,
 152                                      $reference = null, $contact = null)
 153     {
 154         $this->message = $message;
 155         $this->text = $text;
 156         $this->contact = $contact;
 157         $this->reference = $reference;
 158     }
 159
 160     function getReturnTo()
 161     {
 162         if ($this->message &&
 163             $this->message->hasKey(Auth_OpenID_OPENID_NS, 'return_to')) {
 164             return $this->message->getArg(Auth_OpenID_OPENID_NS,
 165                                           'return_to');
 166         } else {
 167             return null;
 168         }
 169     }
 170
 171     /**
 172      * Returns the return_to URL for the request which caused this
 173      * error.
 174      */
 175     function hasReturnTo()
 176     {
 177         return $this->getReturnTo() !== null;
 178     }
 179
 180     /**
 181      * Encodes this error's response as a URL suitable for
 182      * redirection.  If the response has no return_to, another
 183      * Auth_OpenID_ServerError is returned.
 184      */
 185     function encodeToURL()
 186     {
 187         if (!$this->message) {
 188             return null;
 189         }
 190
 191         $msg = $this->toMessage();
 192         return $msg->toURL($this->getReturnTo());
 193     }
 194
 195     /**
 196      * Encodes the response to key-value form.  This is a
 197      * machine-readable format used to respond to messages which came
 198      * directly from the consumer and not through the user-agent.  See
 199      * the OpenID specification.
 200      */
 201     function encodeToKVForm()
 202     {
 203         return Auth_OpenID_KVForm::fromArray(
 204                                       array('mode' => 'error',
 205                                             'error' => $this->toString()));
 206     }
 207
 208     function toFormMarkup($form_tag_attrs=null)
 209     {
 210         $msg = $this->toMessage();
 211         return $msg->toFormMarkup($this->getReturnTo(), $form_tag_attrs);
 212     }
 213
 214     function toHTML($form_tag_attrs=null)
 215     {
 216         return Auth_OpenID::autoSubmitHTML(
 217                       $this->toFormMarkup($form_tag_attrs));
 218     }
 219
 220     function toMessage()
 221     {
 222         // Generate a Message object for sending to the relying party,
 223         // after encoding.
 224         $namespace = $this->message->getOpenIDNamespace();
 225         $reply = new Auth_OpenID_Message($namespace);
 226         $reply->setArg(Auth_OpenID_OPENID_NS, 'mode', 'error');
 227         $reply->setArg(Auth_OpenID_OPENID_NS, 'error', $this->toString());
 228
 229         if ($this->contact !== null) {
 230             $reply->setArg(Auth_OpenID_OPENID_NS, 'contact', $this->contact);
 231         }
 232
 233         if ($this->reference !== null) {
 234             $reply->setArg(Auth_OpenID_OPENID_NS, 'reference',
 235                            $this->reference);
 236         }
 237
 238         return $reply;
 239     }
 240
 241     /**
 242      * Returns one of Auth_OpenID_ENCODE_URL,
 243      * Auth_OpenID_ENCODE_KVFORM, or null, depending on the type of
 244      * encoding expected for this error's payload.
 245      */
 246     function whichEncoding()
 247     {
 248         global $_Auth_OpenID_Request_Modes;
 249
 250         if ($this->hasReturnTo()) {
 251             if ($this->message->isOpenID2() &&
 252                 (strlen($this->encodeToURL()) >
 253                    Auth_OpenID_OPENID1_URL_LIMIT)) {
 254                 return Auth_OpenID_ENCODE_HTML_FORM;
 255             } else {
 256                 return Auth_OpenID_ENCODE_URL;
 257             }
 258         }
 259
 260         if (!$this->message) {
 261             return null;
 262         }
 263
 264         $mode = $this->message->getArg(Auth_OpenID_OPENID_NS,
 265                                        'mode');
 266
 267         if ($mode) {
 268             if (!in_array($mode, $_Auth_OpenID_Request_Modes)) {
 269                 return Auth_OpenID_ENCODE_KVFORM;
 270             }
 271         }
 272         return null;
 273     }
 274
 275     /**
 276      * Returns this error message.
 277      */
 278     function toString()
 279     {
 280         if ($this->text) {
 281             return $this->text;
 282         } else {
 283             return get_class($this) . " error";
 284         }
 285     }
 286 }
 287
 288 /**
 289  * Error returned by the server code when a return_to is absent from a
 290  * request.
 291  *
 292  * @package OpenID
 293  */
 294 class Auth_OpenID_NoReturnToError extends Auth_OpenID_ServerError {
 295     function Auth_OpenID_NoReturnToError($message = null,
 296                                          $text = "No return_to URL available")
 297     {
 298         parent::Auth_OpenID_ServerError($message, $text);
 299     }
 300
 301     function toString()
 302     {
 303         return "No return_to available";
 304     }
 305 }
 306
 307 /**
 308  * An error indicating that the return_to URL is malformed.
 309  *
 310  * @package OpenID
 311  */
 312 class Auth_OpenID_MalformedReturnURL extends Auth_OpenID_ServerError {
 313     function Auth_OpenID_MalformedReturnURL($message, $return_to)
 314     {
 315         $this->return_to = $return_to;
 316         parent::Auth_OpenID_ServerError($message, "malformed return_to URL");
 317     }
 318 }
 319
 320 /**
 321  * This error is returned when the trust_root value is malformed.
 322  *
 323  * @package OpenID
 324  */
 325 class Auth_OpenID_MalformedTrustRoot extends Auth_OpenID_ServerError {
 326     function Auth_OpenID_MalformedTrustRoot($message = null,
 327                                             $text = "Malformed trust root")
 328     {
 329         parent::Auth_OpenID_ServerError($message, $text);
 330     }
 331
 332     function toString()
 333     {
 334         return "Malformed trust root";
 335     }
 336 }
 337
 338 /**
 339  * The base class for all server request classes.
 340  *
 341  * @package OpenID
 342  */
 343 class Auth_OpenID_Request {
 344     var $mode = null;
 345 }
 346
 347 /**
 348  * A request to verify the validity of a previous response.
 349  *
 350  * @package OpenID
 351  */
 352 class Auth_OpenID_CheckAuthRequest extends Auth_OpenID_Request {
 353     var $mode = "check_authentication";
 354     var $invalidate_handle = null;
 355
 356     function Auth_OpenID_CheckAuthRequest($assoc_handle, $signed,
 357                                           $invalidate_handle = null)
 358     {
 359         $this->assoc_handle = $assoc_handle;
 360         $this->signed = $signed;
 361         if ($invalidate_handle !== null) {
 362             $this->invalidate_handle = $invalidate_handle;
 363         }
 364         $this->namespace = Auth_OpenID_OPENID2_NS;
 365         $this->message = null;
 366     }
 367
 368     function fromMessage($message, $server=null)
 369     {
 370         $required_keys = array('assoc_handle', 'sig', 'signed');
 371
 372         foreach ($required_keys as $k) {
 373             if (!$message->getArg(Auth_OpenID_OPENID_NS, $k)) {
 374                 return new Auth_OpenID_ServerError($message,
 375                     sprintf("%s request missing required parameter %s from \
 376                             query", "check_authentication", $k));
 377             }
 378         }
 379
 380         $assoc_handle = $message->getArg(Auth_OpenID_OPENID_NS, 'assoc_handle');
 381         $sig = $message->getArg(Auth_OpenID_OPENID_NS, 'sig');
 382
 383         $signed_list = $message->getArg(Auth_OpenID_OPENID_NS, 'signed');
 384         $signed_list = explode(",", $signed_list);
 385
 386         $signed = $message;
 387         if ($signed->hasKey(Auth_OpenID_OPENID_NS, 'mode')) {
 388             $signed->setArg(Auth_OpenID_OPENID_NS, 'mode', 'id_res');
 389         }
 390
 391         $result = new Auth_OpenID_CheckAuthRequest($assoc_handle, $signed);
 392         $result->message = $message;
 393         $result->sig = $sig;
 394         $result->invalidate_handle = $message->getArg(Auth_OpenID_OPENID_NS,
 395                                                       'invalidate_handle');
 396         return $result;
 397     }
 398
 399     function answer(&$signatory)
 400     {
 401         $is_valid = $signatory->verify($this->assoc_handle, $this->signed);
 402
 403         // Now invalidate that assoc_handle so it this checkAuth
 404         // message cannot be replayed.
 405         $signatory->invalidate($this->assoc_handle, true);
 406         $response = new Auth_OpenID_ServerResponse($this);
 407
 408         $response->fields->setArg(Auth_OpenID_OPENID_NS,
 409                                   'is_valid',
 410                                   ($is_valid ? "true" : "false"));
 411
 412         if ($this->invalidate_handle) {
 413             $assoc = $signatory->getAssociation($this->invalidate_handle,
 414                                                 false);
 415             if (!$assoc) {
 416                 $response->fields->setArg(Auth_OpenID_OPENID_NS,
 417                                           'invalidate_handle',
 418                                           $this->invalidate_handle);
 419             }
 420         }
 421         return $response;
 422     }
 423 }
 424
 425 /**
 426  * A class implementing plaintext server sessions.
 427  *
 428  * @package OpenID
 429  */
 430 class Auth_OpenID_PlainTextServerSession {
 431     /**
 432      * An object that knows how to handle association requests with no
 433      * session type.
 434      */
 435     var $session_type = 'no-encryption';
 436     var $needs_math = false;
 437     var $allowed_assoc_types = array('HMAC-SHA1', 'HMAC-SHA256');
 438
 439     function fromMessage($unused_request)
 440     {
 441         return new Auth_OpenID_PlainTextServerSession();
 442     }
 443
 444     function answer($secret)
 445     {
 446         return array('mac_key' => base64_encode($secret));
 447     }
 448 }
 449
 450 /**
 451  * A class implementing DH-SHA1 server sessions.
 452  *
 453  * @package OpenID
 454  */
 455 class Auth_OpenID_DiffieHellmanSHA1ServerSession {
 456     /**
 457      * An object that knows how to handle association requests with
 458      * the Diffie-Hellman session type.
 459      */
 460
 461     var $session_type = 'DH-SHA1';
 462     var $needs_math = true;
 463     var $allowed_assoc_types = array('HMAC-SHA1');
 464     var $hash_func = 'Auth_OpenID_SHA1';
 465
 466     function Auth_OpenID_DiffieHellmanSHA1ServerSession($dh, $consumer_pubkey)
 467     {
 468         $this->dh = $dh;
 469         $this->consumer_pubkey = $consumer_pubkey;
 470     }
 471
 472     function getDH($message)
 473     {
 474         $dh_modulus = $message->getArg(Auth_OpenID_OPENID_NS, 'dh_modulus');
 475         $dh_gen = $message->getArg(Auth_OpenID_OPENID_NS, 'dh_gen');
 476
 477         if ((($dh_modulus === null) && ($dh_gen !== null)) ||
 478             (($dh_gen === null) && ($dh_modulus !== null))) {
 479
 480             if ($dh_modulus === null) {
 481                 $missing = 'modulus';
 482             } else {
 483                 $missing = 'generator';
 484             }
 485
 486             return new Auth_OpenID_ServerError($message,
 487                                 'If non-default modulus or generator is '.
 488                                 'supplied, both must be supplied.  Missing '.
 489                                 $missing);
 490         }
 491
 492         $lib =& Auth_OpenID_getMathLib();
 493
 494         if ($dh_modulus || $dh_gen) {
 495             $dh_modulus = $lib->base64ToLong($dh_modulus);
 496             $dh_gen = $lib->base64ToLong($dh_gen);
 497             if ($lib->cmp($dh_modulus, 0) == 0 ||
 498                 $lib->cmp($dh_gen, 0) == 0) {
 499                 return new Auth_OpenID_ServerError(
 500                   $message, "Failed to parse dh_mod or dh_gen");
 501             }
 502             $dh = new Auth_OpenID_DiffieHellman($dh_modulus, $dh_gen);
 503         } else {
 504             $dh = new Auth_OpenID_DiffieHellman();
 505         }
 506
 507         $consumer_pubkey = $message->getArg(Auth_OpenID_OPENID_NS,
 508                                             'dh_consumer_public');
 509         if ($consumer_pubkey === null) {
 510             return new Auth_OpenID_ServerError($message,
 511                                   'Public key for DH-SHA1 session '.
 512                                   'not found in query');
 513         }
 514
 515         $consumer_pubkey =
 516             $lib->base64ToLong($consumer_pubkey);
 517
 518         if ($consumer_pubkey === false) {
 519             return new Auth_OpenID_ServerError($message,
 520                                        "dh_consumer_public is not base64");
 521         }
 522
 523         return array($dh, $consumer_pubkey);
 524     }
 525
 526     function fromMessage($message)
 527     {
 528         $result = Auth_OpenID_DiffieHellmanSHA1ServerSession::getDH($message);
 529
 530         if (is_a($result, 'Auth_OpenID_ServerError')) {
 531             return $result;
 532         } else {
 533             list($dh, $consumer_pubkey) = $result;
 534             return new Auth_OpenID_DiffieHellmanSHA1ServerSession($dh,
 535                                                     $consumer_pubkey);
 536         }
 537     }
 538
 539     function answer($secret)
 540     {
 541         $lib =& Auth_OpenID_getMathLib();
 542         $mac_key = $this->dh->xorSecret($this->consumer_pubkey, $secret,
 543                                         $this->hash_func);
 544         return array(
 545            'dh_server_public' =>
 546                 $lib->longToBase64($this->dh->public),
 547            'enc_mac_key' => base64_encode($mac_key));
 548     }
 549 }
 550
 551 /**
 552  * A class implementing DH-SHA256 server sessions.
 553  *
 554  * @package OpenID
 555  */
 556 class Auth_OpenID_DiffieHellmanSHA256ServerSession
 557       extends Auth_OpenID_DiffieHellmanSHA1ServerSession {
 558
 559     var $session_type = 'DH-SHA256';
 560     var $hash_func = 'Auth_OpenID_SHA256';
 561     var $allowed_assoc_types = array('HMAC-SHA256');
 562
 563     function fromMessage($message)
 564     {
 565         $result = Auth_OpenID_DiffieHellmanSHA1ServerSession::getDH($message);
 566
 567         if (is_a($result, 'Auth_OpenID_ServerError')) {
 568             return $result;
 569         } else {
 570             list($dh, $consumer_pubkey) = $result;
 571             return new Auth_OpenID_DiffieHellmanSHA256ServerSession($dh,
 572                                                       $consumer_pubkey);
 573         }
 574     }
 575 }
 576
 577 /**
 578  * A request to associate with the server.
 579  *
 580  * @package OpenID
 581  */
 582 class Auth_OpenID_AssociateRequest extends Auth_OpenID_Request {
 583     var $mode = "associate";
 584
 585     function getSessionClasses()
 586     {
 587         return array(
 588           'no-encryption' => 'Auth_OpenID_PlainTextServerSession',
 589           'DH-SHA1' => 'Auth_OpenID_DiffieHellmanSHA1ServerSession',
 590           'DH-SHA256' => 'Auth_OpenID_DiffieHellmanSHA256ServerSession');
 591     }
 592
 593     function Auth_OpenID_AssociateRequest(&$session, $assoc_type)
 594     {
 595         $this->session =& $session;
 596         $this->namespace = Auth_OpenID_OPENID2_NS;
 597         $this->assoc_type = $assoc_type;
 598     }
 599
 600     function fromMessage($message, $server=null)
 601     {
 602         if ($message->isOpenID1()) {
 603             $session_type = $message->getArg(Auth_OpenID_OPENID_NS,
 604                                              'session_type');
 605
 606             if ($session_type == 'no-encryption') {
 607                 // oidutil.log('Received OpenID 1 request with a no-encryption '
 608                 //             'assocaition session type. Continuing anyway.')
 609             } else if (!$session_type) {
 610                 $session_type = 'no-encryption';
 611             }
 612         } else {
 613             $session_type = $message->getArg(Auth_OpenID_OPENID_NS,
 614                                              'session_type');
 615             if ($session_type === null) {
 616                 return new Auth_OpenID_ServerError($message,
 617                   "session_type missing from request");
 618             }
 619         }
 620
 621         $session_class = Auth_OpenID::arrayGet(
 622            Auth_OpenID_AssociateRequest::getSessionClasses(),
 623            $session_type);
 624
 625         if ($session_class === null) {
 626             return new Auth_OpenID_ServerError($message,
 627                                                "Unknown session type " .
 628                                                $session_type);
 629         }
 630
 631         $session = call_user_func(array($session_class, 'fromMessage'),
 632                                   $message);
 633         if (is_a($session, 'Auth_OpenID_ServerError')) {
 634             return $session;
 635         }
 636
 637         $assoc_type = $message->getArg(Auth_OpenID_OPENID_NS,
 638                                        'assoc_type', 'HMAC-SHA1');
 639
 640         if (!in_array($assoc_type, $session->allowed_assoc_types)) {
 641             $fmt = "Session type %s does not support association type %s";
 642             return new Auth_OpenID_ServerError($message,
 643               sprintf($fmt, $session_type, $assoc_type));
 644         }
 645
 646         $obj = new Auth_OpenID_AssociateRequest($session, $assoc_type);
 647         $obj->message = $message;
 648         $obj->namespace = $message->getOpenIDNamespace();
 649         return $obj;
 650     }
 651
 652     function answer($assoc)
 653     {
 654         $response = new Auth_OpenID_ServerResponse($this);
 655         $response->fields->updateArgs(Auth_OpenID_OPENID_NS,
 656            array(
 657                  'expires_in' => sprintf('%d', $assoc->getExpiresIn()),
 658                  'assoc_type' => $this->assoc_type,
 659                  'assoc_handle' => $assoc->handle));
 660
 661         $response->fields->updateArgs(Auth_OpenID_OPENID_NS,
 662            $this->session->answer($assoc->secret));
 663
 664         if (! ($this->session->session_type == 'no-encryption'
 665                && $this->message->isOpenID1())) {
 666             $response->fields->setArg(Auth_OpenID_OPENID_NS,
 667                                       'session_type',
 668                                       $this->session->session_type);
 669         }
 670
 671         return $response;
 672     }
 673
 674     function answerUnsupported($text_message,
 675                                $preferred_association_type=null,
 676                                $preferred_session_type=null)
 677     {
 678         if ($this->message->isOpenID1()) {
 679             return new Auth_OpenID_ServerError($this->message);
 680         }
 681
 682         $response = new Auth_OpenID_ServerResponse($this);
 683         $response->fields->setArg(Auth_OpenID_OPENID_NS,
 684                                   'error_code', 'unsupported-type');
 685         $response->fields->setArg(Auth_OpenID_OPENID_NS,
 686                                   'error', $text_message);
 687
 688         if ($preferred_association_type) {
 689             $response->fields->setArg(Auth_OpenID_OPENID_NS,
 690                                       'assoc_type',
 691                                       $preferred_association_type);
 692         }
 693
 694         if ($preferred_session_type) {
 695             $response->fields->setArg(Auth_OpenID_OPENID_NS,
 696                                       'session_type',
 697                                       $preferred_session_type);
 698         }
 699
 700         return $response;
 701     }
 702 }
 703
 704 /**
 705  * A request to confirm the identity of a user.
 706  *
 707  * @package OpenID
 708  */
 709 class Auth_OpenID_CheckIDRequest extends Auth_OpenID_Request {
 710     /**
 711      * Return-to verification callback.  Default is
 712      * Auth_OpenID_verifyReturnTo from TrustRoot.php.
 713      */
 714     var $verifyReturnTo = 'Auth_OpenID_verifyReturnTo';
 715
 716     /**
 717      * The mode of this request.
 718      */
 719     var $mode = "checkid_setup"; // or "checkid_immediate"
 720
 721     /**
 722      * Whether this request is for immediate mode.
 723      */
 724     var $immediate = false;
 725
 726     /**
 727      * The trust_root value for this request.
 728      */
 729     var $trust_root = null;
 730
 731     /**
 732      * The OpenID namespace for this request.
 733      * deprecated since version 2.0.2
 734      */
 735     var $namespace;
 736
 737     function make(&$message, $identity, $return_to, $trust_root = null,
 738                   $immediate = false, $assoc_handle = null, $server = null)
 739     {
 740         if ($server === null) {
 741             return new Auth_OpenID_ServerError($message,
 742                                                "server must not be null");
 743         }
 744
 745         if ($return_to &&
 746             !Auth_OpenID_TrustRoot::_parse($return_to)) {
 747             return new Auth_OpenID_MalformedReturnURL($message, $return_to);
 748         }
 749
 750         $r = new Auth_OpenID_CheckIDRequest($identity, $return_to,
 751                                             $trust_root, $immediate,
 752                                             $assoc_handle, $server);
 753
 754         $r->namespace = $message->getOpenIDNamespace();
 755         $r->message =& $message;
 756
 757         if (!$r->trustRootValid()) {
 758             return new Auth_OpenID_UntrustedReturnURL($message,
 759                                                       $return_to,
 760                                                       $trust_root);
 761         } else {
 762             return $r;
 763         }
 764     }
 765
 766     function Auth_OpenID_CheckIDRequest($identity, $return_to,
 767                                         $trust_root = null, $immediate = false,
 768                                         $assoc_handle = null, $server = null)
 769     {
 770         $this->namespace = Auth_OpenID_OPENID2_NS;
 771         $this->assoc_handle = $assoc_handle;
 772         $this->identity = $identity;
 773         $this->claimed_id = $identity;
 774         $this->return_to = $return_to;
 775         $this->trust_root = $trust_root;
 776         $this->server =& $server;
 777
 778         if ($immediate) {
 779             $this->immediate = true;
 780             $this->mode = "checkid_immediate";
 781         } else {
 782             $this->immediate = false;
 783             $this->mode = "checkid_setup";
 784         }
 785     }
 786
 787     function equals($other)
 788     {
 789         return (
 790                 (is_a($other, 'Auth_OpenID_CheckIDRequest')) &&
 791                 ($this->namespace == $other->namespace) &&
 792                 ($this->assoc_handle == $other->assoc_handle) &&
 793                 ($this->identity == $other->identity) &&
 794                 ($this->claimed_id == $other->claimed_id) &&
 795                 ($this->return_to == $other->return_to) &&
 796                 ($this->trust_root == $other->trust_root));
 797     }
 798
 799     /*
 800      * Does the relying party publish the return_to URL for this
 801      * response under the realm? It is up to the provider to set a
 802      * policy for what kinds of realms should be allowed. This
 803      * return_to URL verification reduces vulnerability to data-theft
 804      * attacks based on open proxies, corss-site-scripting, or open
 805      * redirectors.
 806      *
 807      * This check should only be performed after making sure that the
 808      * return_to URL matches the realm.
 809      *
 810      * @return true if the realm publishes a document with the
 811      * return_to URL listed, false if not or if discovery fails
 812      */
 813     function returnToVerified()
 814     {
 815         return call_user_func_array($this->verifyReturnTo,
 816                                     array($this->trust_root, $this->return_to));
 817     }
 818
 819     function fromMessage(&$message, $server)
 820     {
 821         $mode = $message->getArg(Auth_OpenID_OPENID_NS, 'mode');
 822         $immediate = null;
 823
 824         if ($mode == "checkid_immediate") {
 825             $immediate = true;
 826             $mode = "checkid_immediate";
 827         } else {
 828             $immediate = false;
 829             $mode = "checkid_setup";
 830         }
 831
 832         $return_to = $message->getArg(Auth_OpenID_OPENID_NS,
 833                                       'return_to');
 834
 835         if (($message->isOpenID1()) &&
 836             (!$return_to)) {
 837             $fmt = "Missing required field 'return_to' from checkid request";
 838             return new Auth_OpenID_ServerError($message, $fmt);
 839         }
 840
 841         $identity = $message->getArg(Auth_OpenID_OPENID_NS,
 842                                      'identity');
 843         $claimed_id = $message->getArg(Auth_OpenID_OPENID_NS, 'claimed_id');
 844         if ($message->isOpenID1()) {
 845             if ($identity === null) {
 846                 $s = "OpenID 1 message did not contain openid.identity";
 847                 return new Auth_OpenID_ServerError($message, $s);
 848             }
 849         } else {
 850             if ($identity && !$claimed_id) {
 851                 $s = "OpenID 2.0 message contained openid.identity but not " .
 852                   "claimed_id";
 853                 return new Auth_OpenID_ServerError($message, $s);
 854             } else if ($claimed_id && !$identity) {
 855                 $s = "OpenID 2.0 message contained openid.claimed_id " .
 856                   "but not identity";
 857                 return new Auth_OpenID_ServerError($message, $s);
 858             }
 859         }
 860
 861         // There's a case for making self.trust_root be a TrustRoot
 862         // here.  But if TrustRoot isn't currently part of the
 863         // "public" API, I'm not sure it's worth doing.
 864         if ($message->isOpenID1()) {
 865             $trust_root_param = 'trust_root';
 866         } else {
 867             $trust_root_param = 'realm';
 868         }
 869         $trust_root = $message->getArg(Auth_OpenID_OPENID_NS,
 870                                        $trust_root_param);
 871         if (! $trust_root) {
 872             $trust_root = $return_to;
 873         }
 874
 875         if (! $message->isOpenID1() &&
 876             ($return_to === null) &&
 877             ($trust_root === null)) {
 878             return new Auth_OpenID_ServerError($message,
 879               "openid.realm required when openid.return_to absent");
 880         }
 881
 882         $assoc_handle = $message->getArg(Auth_OpenID_OPENID_NS,
 883                                          'assoc_handle');
 884
 885         $obj = Auth_OpenID_CheckIDRequest::make($message,
 886                                                 $identity,
 887                                                 $return_to,
 888                                                 $trust_root,
 889                                                 $immediate,
 890                                                 $assoc_handle,
 891                                                 $server);
 892
 893         if (is_a($obj, 'Auth_OpenID_ServerError')) {
 894             return $obj;
 895         }
 896
 897         $obj->claimed_id = $claimed_id;
 898
 899         return $obj;
 900     }
 901
 902     function idSelect()
 903     {
 904         // Is the identifier to be selected by the IDP?
 905         // So IDPs don't have to import the constant
 906         return $this->identity == Auth_OpenID_IDENTIFIER_SELECT;
 907     }
 908
 909     function trustRootValid()
 910     {
 911         if (!$this->trust_root) {
 912             return true;
 913         }
 914
 915         $tr = Auth_OpenID_TrustRoot::_parse($this->trust_root);
 916         if ($tr === false) {
 917             return new Auth_OpenID_MalformedTrustRoot($this->message,
 918                                                       $this->trust_root);
 919         }
 920
 921         if ($this->return_to !== null) {
 922             return Auth_OpenID_TrustRoot::match($this->trust_root,
 923                                                 $this->return_to);
 924         } else {
 925             return true;
 926         }
 927     }
 928
 929     /**
 930      * Respond to this request.  Return either an
 931      * {@link Auth_OpenID_ServerResponse} or
 932      * {@link Auth_OpenID_ServerError}.
 933      *
 934      * @param bool $allow Allow this user to claim this identity, and
 935      * allow the consumer to have this information?
 936      *
 937      * @param string $server_url DEPRECATED.  Passing $op_endpoint to
 938      * the {@link Auth_OpenID_Server} constructor makes this optional.
 939      *
 940      * When an OpenID 1.x immediate mode request does not succeed, it
 941      * gets back a URL where the request may be carried out in a
 942      * not-so-immediate fashion.  Pass my URL in here (the fully
 943      * qualified address of this server's endpoint, i.e.
 944      * http://example.com/server), and I will use it as a base for the
 945      * URL for a new request.
 946      *
 947      * Optional for requests where {@link $immediate} is false or
 948      * $allow is true.
 949      *
 950      * @param string $identity The OP-local identifier to answer with.
 951      * Only for use when the relying party requested identifier
 952      * selection.
 953      *
 954      * @param string $claimed_id The claimed identifier to answer
 955      * with, for use with identifier selection in the case where the
 956      * claimed identifier and the OP-local identifier differ,
 957      * i.e. when the claimed_id uses delegation.
 958      *
 959      * If $identity is provided but this is not, $claimed_id will
 960      * default to the value of $identity.  When answering requests
 961      * that did not ask for identifier selection, the response
 962      * $claimed_id will default to that of the request.
 963      *
 964      * This parameter is new in OpenID 2.0.
 965      *
 966      * @return mixed
 967      */
 968     function answer($allow, $server_url = null, $identity = null,
 969                     $claimed_id = null)
 970     {
 971         if (!$this->return_to) {
 972             return new Auth_OpenID_NoReturnToError();
 973         }
 974
 975         if (!$server_url) {
 976             if ((!$this->message->isOpenID1()) &&
 977                 (!$this->server->op_endpoint)) {
 978                 return new Auth_OpenID_ServerError(null,
 979                   "server should be constructed with op_endpoint to " .
 980                   "respond to OpenID 2.0 messages.");
 981             }
 982
 983             $server_url = $this->server->op_endpoint;
 984         }
 985
 986         if ($allow) {
 987             $mode = 'id_res';
 988         } else if ($this->message->isOpenID1()) {
 989             if ($this->immediate) {
 990                 $mode = 'id_res';
 991             } else {
 992                 $mode = 'cancel';
 993             }
 994         } else {
 995             if ($this->immediate) {
 996                 $mode = 'setup_needed';
 997             } else {
 998                 $mode = 'cancel';
 999             }
1000         }
1001
1002         if (!$this->trustRootValid()) {
1003             return new Auth_OpenID_UntrustedReturnURL(null,
1004                                                       $this->return_to,
1005                                                       $this->trust_root);
1006         }
1007
1008         $response = new Auth_OpenID_ServerResponse($this);
1009
1010         if ($claimed_id &&
1011             ($this->message->isOpenID1())) {
1012             return new Auth_OpenID_ServerError(null,
1013               "claimed_id is new in OpenID 2.0 and not " .
1014               "available for ".$this->namespace);
1015         }
1016
1017         if ($identity && !$claimed_id) {
1018             $claimed_id = $identity;
1019         }
1020
1021         if ($allow) {
1022
1023             if ($this->identity == Auth_OpenID_IDENTIFIER_SELECT) {
1024                 if (!$identity) {
1025                     return new Auth_OpenID_ServerError(null,
1026                       "This request uses IdP-driven identifier selection.  " .
1027                       "You must supply an identifier in the response.");
1028                 }
1029
1030                 $response_identity = $identity;
1031                 $response_claimed_id = $claimed_id;
1032
1033             } else if ($this->identity) {
1034                 if ($identity &&
1035                     ($this->identity != $identity)) {
1036                     $fmt = "Request was for %s, cannot reply with identity %s";
1037                     return new Auth_OpenID_ServerError(null,
1038                       sprintf($fmt, $this->identity, $identity));
1039                 }
1040
1041                 $response_identity = $this->identity;
1042                 $response_claimed_id = $this->claimed_id;
1043             } else {
1044                 if ($identity) {
1045                     return new Auth_OpenID_ServerError(null,
1046                       "This request specified no identity and " .
1047                       "you supplied ".$identity);
1048                 }
1049
1050                 $response_identity = null;
1051             }
1052
1053             if (($this->message->isOpenID1()) &&
1054                 ($response_identity === null)) {
1055                 return new Auth_OpenID_ServerError(null,
1056                   "Request was an OpenID 1 request, so response must " .
1057                   "include an identifier.");
1058             }
1059
1060             $response->fields->updateArgs(Auth_OpenID_OPENID_NS,
1061                    array('mode' => $mode,
1062                          'return_to' => $this->return_to,
1063                          'response_nonce' => Auth_OpenID_mkNonce()));
1064
1065             if (!$this->message->isOpenID1()) {
1066                 $response->fields->setArg(Auth_OpenID_OPENID_NS,
1067                                           'op_endpoint', $server_url);
1068             }
1069
1070             if ($response_identity !== null) {
1071                 $response->fields->setArg(
1072                                           Auth_OpenID_OPENID_NS,
1073                                           'identity',
1074                                           $response_identity);
1075                 if ($this->message->isOpenID2()) {
1076                     $response->fields->setArg(
1077                                               Auth_OpenID_OPENID_NS,
1078                                               'claimed_id',
1079                                               $response_claimed_id);
1080                 }
1081             }
1082
1083         } else {
1084             $response->fields->setArg(Auth_OpenID_OPENID_NS,
1085                                       'mode', $mode);
1086
1087             if ($this->immediate) {
1088                 if (($this->message->isOpenID1()) &&
1089                     (!$server_url)) {
1090                     return new Auth_OpenID_ServerError(null,
1091                                  'setup_url is required for $allow=false \
1092                                   in OpenID 1.x immediate mode.');
1093                 }
1094
1095                 $setup_request =& new Auth_OpenID_CheckIDRequest(
1096                                                 $this->identity,
1097                                                 $this->return_to,
1098                                                 $this->trust_root,
1099                                                 false,
1100                                                 $this->assoc_handle,
1101                                                 $this->server);
1102                 $setup_request->message = $this->message;
1103
1104                 $setup_url = $setup_request->encodeToURL($server_url);
1105
1106                 if ($setup_url === null) {
1107                     return new Auth_OpenID_NoReturnToError();
1108                 }
1109
1110                 $response->fields->setArg(Auth_OpenID_OPENID_NS,
1111                                           'user_setup_url',
1112                                           $setup_url);
1113             }
1114         }
1115
1116         return $response;
1117     }
1118
1119     function encodeToURL($server_url)
1120     {
1121         if (!$this->return_to) {
1122             return new Auth_OpenID_NoReturnToError();
1123         }
1124
1125         // Imported from the alternate reality where these classes are
1126         // used in both the client and server code, so Requests are
1127         // Encodable too.  That's right, code imported from alternate
1128         // realities all for the love of you, id_res/user_setup_url.
1129
1130         $q = array('mode' => $this->mode,
1131                    'identity' => $this->identity,
1132                    'claimed_id' => $this->claimed_id,
1133                    'return_to' => $this->return_to);
1134
1135         if ($this->trust_root) {
1136             if ($this->message->isOpenID1()) {
1137                 $q['trust_root'] = $this->trust_root;
1138             } else {
1139                 $q['realm'] = $this->trust_root;
1140             }
1141         }
1142
1143         if ($this->assoc_handle) {
1144             $q['assoc_handle'] = $this->assoc_handle;
1145         }
1146
1147         $response = new Auth_OpenID_Message(
1148             $this->message->getOpenIDNamespace());
1149         $response->updateArgs(Auth_OpenID_OPENID_NS, $q);
1150         return $response->toURL($server_url);
1151     }
1152
1153     function getCancelURL()
1154     {
1155         if (!$this->return_to) {
1156             return new Auth_OpenID_NoReturnToError();
1157         }
1158
1159         if ($this->immediate) {
1160             return new Auth_OpenID_ServerError(null,
1161                                                "Cancel is not an appropriate \
1162                                                response to immediate mode \
1163                                                requests.");
1164         }
1165
1166         $response = new Auth_OpenID_Message(
1167             $this->message->getOpenIDNamespace());
1168         $response->setArg(Auth_OpenID_OPENID_NS, 'mode', 'cancel');
1169         return $response->toURL($this->return_to);
1170     }
1171 }
1172
1173 /**
1174  * This class encapsulates the response to an OpenID server request.
1175  *
1176  * @package OpenID
1177  */
1178 class Auth_OpenID_ServerResponse {
1179
1180     function Auth_OpenID_ServerResponse(&$request)
1181     {
1182         $this->request =& $request;
1183         $this->fields = new Auth_OpenID_Message($this->request->namespace);
1184     }
1185
1186     function whichEncoding()
1187     {
1188       global $_Auth_OpenID_Request_Modes;
1189
1190         if (in_array($this->request->mode, $_Auth_OpenID_Request_Modes)) {
1191             if ($this->fields->isOpenID2() &&
1192                 (strlen($this->encodeToURL()) >
1193                    Auth_OpenID_OPENID1_URL_LIMIT)) {
1194                 return Auth_OpenID_ENCODE_HTML_FORM;
1195             } else {
1196                 return Auth_OpenID_ENCODE_URL;
1197             }
1198         } else {
1199             return Auth_OpenID_ENCODE_KVFORM;
1200         }
1201     }
1202
1203     /*
1204      * Returns the form markup for this response.
1205      *
1206      * @return str
1207      */
1208     function toFormMarkup($form_tag_attrs=null)
1209     {
1210         return $this->fields->toFormMarkup($this->request->return_to,
1211                                            $form_tag_attrs);
1212     }
1213
1214     /*
1215      * Returns an HTML document containing the form markup for this
1216      * response that autosubmits with javascript.
1217      */
1218     function toHTML()
1219     {
1220         return Auth_OpenID::autoSubmitHTML($this->toFormMarkup());
1221     }
1222
1223     /*
1224      * Returns True if this response's encoding is ENCODE_HTML_FORM.
1225      * Convenience method for server authors.
1226      *
1227      * @return bool
1228      */
1229     function renderAsForm()
1230     {
1231         return $this->whichEncoding() == Auth_OpenID_ENCODE_HTML_FORM;
1232     }
1233
1234
1235     function encodeToURL()
1236     {
1237         return $this->fields->toURL($this->request->return_to);
1238     }
1239
1240     function addExtension($extension_response)
1241     {
1242         $extension_response->toMessage($this->fields);
1243     }
1244
1245     function needsSigning()
1246     {
1247         return $this->fields->getArg(Auth_OpenID_OPENID_NS,
1248                                      'mode') == 'id_res';
1249     }
1250
1251     function encodeToKVForm()
1252     {
1253         return $this->fields->toKVForm();
1254     }
1255 }
1256
1257 /**
1258  * A web-capable response object which you can use to generate a
1259  * user-agent response.
1260  *
1261  * @package OpenID
1262  */
1263 class Auth_OpenID_WebResponse {
1264     var $code = AUTH_OPENID_HTTP_OK;
1265     var $body = "";
1266
1267     function Auth_OpenID_WebResponse($code = null, $headers = null,
1268                                      $body = null)
1269     {
1270         if ($code) {
1271             $this->code = $code;
1272         }
1273
1274         if ($headers !== null) {
1275             $this->headers = $headers;
1276         } else {
1277             $this->headers = array();
1278         }
1279
1280         if ($body !== null) {
1281             $this->body = $body;
1282         }
1283     }
1284 }
1285
1286 /**
1287  * Responsible for the signature of query data and the verification of
1288  * OpenID signature values.
1289  *
1290  * @package OpenID
1291  */
1292 class Auth_OpenID_Signatory {
1293
1294     // = 14 * 24 * 60 * 60; # 14 days, in seconds
1295     var $SECRET_LIFETIME = 1209600;
1296
1297     // keys have a bogus server URL in them because the filestore
1298     // really does expect that key to be a URL.  This seems a little
1299     // silly for the server store, since I expect there to be only one
1300     // server URL.
1301     var $normal_key = 'http://localhost/|normal';
1302     var $dumb_key = 'http://localhost/|dumb';
1303
1304     /**
1305      * Create a new signatory using a given store.
1306      */
1307     function Auth_OpenID_Signatory(&$store)
1308     {
1309         // assert store is not None
1310         $this->store =& $store;
1311     }
1312
1313     /**
1314      * Verify, using a given association handle, a signature with
1315      * signed key-value pairs from an HTTP request.
1316      */
1317     function verify($assoc_handle, $message)
1318     {
1319         $assoc = $this->getAssociation($assoc_handle, true);
1320         if (!$assoc) {
1321             // oidutil.log("failed to get assoc with handle %r to verify sig %r"
1322             //             % (assoc_handle, sig))
1323             return false;
1324         }
1325
1326         return $assoc->checkMessageSignature($message);
1327     }
1328
1329     /**
1330      * Given a response, sign the fields in the response's 'signed'
1331      * list, and insert the signature into the response.
1332      */
1333     function sign($response)
1334     {
1335         $signed_response = $response;
1336         $assoc_handle = $response->request->assoc_handle;
1337
1338         if ($assoc_handle) {
1339             // normal mode
1340             $assoc = $this->getAssociation($assoc_handle, false, false);
1341             if (!$assoc || ($assoc->getExpiresIn() <= 0)) {
1342                 // fall back to dumb mode
1343                 $signed_response->fields->setArg(Auth_OpenID_OPENID_NS,
1344                              'invalidate_handle', $assoc_handle);
1345                 $assoc_type = ($assoc ? $assoc->assoc_type : 'HMAC-SHA1');
1346
1347                 if ($assoc && ($assoc->getExpiresIn() <= 0)) {
1348                     $this->invalidate($assoc_handle, false);
1349                 }
1350
1351                 $assoc = $this->createAssociation(true, $assoc_type);
1352             }
1353         } else {
1354             // dumb mode.
1355             $assoc = $this->createAssociation(true);
1356         }
1357
1358         $signed_response->fields = $assoc->signMessage(
1359                                       $signed_response->fields);
1360         return $signed_response;
1361     }
1362
1363     /**
1364      * Make a new association.
1365      */
1366     function createAssociation($dumb = true, $assoc_type = 'HMAC-SHA1')
1367     {
1368         $secret = Auth_OpenID_CryptUtil::getBytes(
1369                     Auth_OpenID_getSecretSize($assoc_type));
1370
1371         $uniq = base64_encode(Auth_OpenID_CryptUtil::getBytes(4));
1372         $handle = sprintf('{%s}{%x}{%s}', $assoc_type, intval(time()), $uniq);
1373
1374         $assoc = Auth_OpenID_Association::fromExpiresIn(
1375                       $this->SECRET_LIFETIME, $handle, $secret, $assoc_type);
1376
1377         if ($dumb) {
1378             $key = $this->dumb_key;
1379         } else {
1380             $key = $this->normal_key;
1381         }
1382
1383         $this->store->storeAssociation($key, $assoc);
1384         return $assoc;
1385     }
1386
1387     /**
1388      * Given an association handle, get the association from the
1389      * store, or return a ServerError or null if something goes wrong.
1390      */
1391     function getAssociation($assoc_handle, $dumb, $check_expiration=true)
1392     {
1393         if ($assoc_handle === null) {
1394             return new Auth_OpenID_ServerError(null,
1395                                      "assoc_handle must not be null");
1396         }
1397
1398         if ($dumb) {
1399             $key = $this->dumb_key;
1400         } else {
1401             $key = $this->normal_key;
1402         }
1403
1404         $assoc = $this->store->getAssociation($key, $assoc_handle);
1405
1406         if (($assoc !== null) && ($assoc->getExpiresIn() <= 0)) {
1407             if ($check_expiration) {
1408                 $this->store->removeAssociation($key, $assoc_handle);
1409                 $assoc = null;
1410             }
1411         }
1412
1413         return $assoc;
1414     }
1415
1416     /**
1417      * Invalidate a given association handle.
1418      */
1419     function invalidate($assoc_handle, $dumb)
1420     {
1421         if ($dumb) {
1422             $key = $this->dumb_key;
1423         } else {
1424             $key = $this->normal_key;
1425         }
1426         $this->store->removeAssociation($key, $assoc_handle);
1427     }
1428 }
1429
1430 /**
1431  * Encode an {@link Auth_OpenID_ServerResponse} to an
1432  * {@link Auth_OpenID_WebResponse}.
1433  *
1434  * @package OpenID
1435  */
1436 class Auth_OpenID_Encoder {
1437
1438     var $responseFactory = 'Auth_OpenID_WebResponse';
1439
1440     /**
1441      * Encode an {@link Auth_OpenID_ServerResponse} and return an
1442      * {@link Auth_OpenID_WebResponse}.
1443      */
1444     function encode(&$response)
1445     {
1446         $cls = $this->responseFactory;
1447
1448         $encode_as = $response->whichEncoding();
1449         if ($encode_as == Auth_OpenID_ENCODE_KVFORM) {
1450             $wr = new $cls(null, null, $response->encodeToKVForm());
1451             if (is_a($response, 'Auth_OpenID_ServerError')) {
1452                 $wr->code = AUTH_OPENID_HTTP_ERROR;
1453             }
1454         } else if ($encode_as == Auth_OpenID_ENCODE_URL) {
1455             $location = $response->encodeToURL();
1456             $wr = new $cls(AUTH_OPENID_HTTP_REDIRECT,
1457                            array('location' => $location));
1458         } else if ($encode_as == Auth_OpenID_ENCODE_HTML_FORM) {
1459           $wr = new $cls(AUTH_OPENID_HTTP_OK, array(),
1460                          $response->toFormMarkup());
1461         } else {
1462             return new Auth_OpenID_EncodingError($response);
1463         }
1464         return $wr;
1465     }
1466 }
1467
1468 /**
1469  * An encoder which also takes care of signing fields when required.
1470  *
1471  * @package OpenID
1472  */
1473 class Auth_OpenID_SigningEncoder extends Auth_OpenID_Encoder {
1474
1475     function Auth_OpenID_SigningEncoder(&$signatory)
1476     {
1477         $this->signatory =& $signatory;
1478     }
1479
1480     /**
1481      * Sign an {@link Auth_OpenID_ServerResponse} and return an
1482      * {@link Auth_OpenID_WebResponse}.
1483      */
1484     function encode(&$response)
1485     {
1486         // the isinstance is a bit of a kludge... it means there isn't
1487         // really an adapter to make the interfaces quite match.
1488         if (!is_a($response, 'Auth_OpenID_ServerError') &&
1489             $response->needsSigning()) {
1490
1491             if (!$this->signatory) {
1492                 return new Auth_OpenID_ServerError(null,
1493                                        "Must have a store to sign request");
1494             }
1495
1496             if ($response->fields->hasKey(Auth_OpenID_OPENID_NS, 'sig')) {
1497                 return new Auth_OpenID_AlreadySigned($response);
1498             }
1499             $response = $this->signatory->sign($response);
1500         }
1501
1502         return parent::encode($response);
1503     }
1504 }
1505
1506 /**
1507  * Decode an incoming query into an Auth_OpenID_Request.
1508  *
1509  * @package OpenID
1510  */
1511 class Auth_OpenID_Decoder {
1512
1513     function Auth_OpenID_Decoder(&$server)
1514     {
1515         $this->server =& $server;
1516
1517         $this->handlers = array(
1518             'checkid_setup' => 'Auth_OpenID_CheckIDRequest',
1519             'checkid_immediate' => 'Auth_OpenID_CheckIDRequest',
1520             'check_authentication' => 'Auth_OpenID_CheckAuthRequest',
1521             'associate' => 'Auth_OpenID_AssociateRequest'
1522             );
1523     }
1524
1525     /**
1526      * Given an HTTP query in an array (key-value pairs), decode it
1527      * into an Auth_OpenID_Request object.
1528      */
1529     function decode($query)
1530     {
1531         if (!$query) {
1532             return null;
1533         }
1534
1535         $message = Auth_OpenID_Message::fromPostArgs($query);
1536
1537         if ($message === null) {
1538             /*
1539              * It's useful to have a Message attached to a
1540              * ProtocolError, so we override the bad ns value to build
1541              * a Message out of it.  Kinda kludgy, since it's made of
1542              * lies, but the parts that aren't lies are more useful
1543              * than a 'None'.
1544              */
1545             $old_ns = $query['openid.ns'];
1546
1547             $query['openid.ns'] = Auth_OpenID_OPENID2_NS;
1548             $message = Auth_OpenID_Message::fromPostArgs($query);
1549             return new Auth_OpenID_ServerError(
1550                   $message,
1551                   sprintf("Invalid OpenID namespace URI: %s", $old_ns));
1552         }
1553
1554         $mode = $message->getArg(Auth_OpenID_OPENID_NS, 'mode');
1555         if (!$mode) {
1556             return new Auth_OpenID_ServerError($message,
1557                                                "No mode value in message");
1558         }
1559
1560         if (Auth_OpenID::isFailure($mode)) {
1561             return new Auth_OpenID_ServerError($message,
1562                                                $mode->message);
1563         }
1564
1565         $handlerCls = Auth_OpenID::arrayGet($this->handlers, $mode,
1566                                             $this->defaultDecoder($message));
1567
1568         if (!is_a($handlerCls, 'Auth_OpenID_ServerError')) {
1569             return call_user_func_array(array($handlerCls, 'fromMessage'),
1570                                         array($message, $this->server));
1571         } else {
1572             return $handlerCls;
1573         }
1574     }
1575
1576     function defaultDecoder($message)
1577     {
1578         $mode = $message->getArg(Auth_OpenID_OPENID_NS, 'mode');
1579
1580         if (Auth_OpenID::isFailure($mode)) {
1581             return new Auth_OpenID_ServerError($message,
1582                                                $mode->message);
1583         }
1584
1585         return new Auth_OpenID_ServerError($message,
1586                        sprintf("Unrecognized OpenID mode %s", $mode));
1587     }
1588 }
1589
1590 /**
1591  * An error that indicates an encoding problem occurred.
1592  *
1593  * @package OpenID
1594  */
1595 class Auth_OpenID_EncodingError {
1596     function Auth_OpenID_EncodingError(&$response)
1597     {
1598         $this->response =& $response;
1599     }
1600 }
1601
1602 /**
1603  * An error that indicates that a response was already signed.
1604  *
1605  * @package OpenID
1606  */
1607 class Auth_OpenID_AlreadySigned extends Auth_OpenID_EncodingError {
1608     // This response is already signed.
1609 }
1610
1611 /**
1612  * An error that indicates that the given return_to is not under the
1613  * given trust_root.
1614  *
1615  * @package OpenID
1616  */
1617 class Auth_OpenID_UntrustedReturnURL extends Auth_OpenID_ServerError {
1618     function Auth_OpenID_UntrustedReturnURL($message, $return_to,
1619                                             $trust_root)
1620     {
1621         parent::Auth_OpenID_ServerError($message, "Untrusted return_to URL");
1622         $this->return_to = $return_to;
1623         $this->trust_root = $trust_root;
1624     }
1625
1626     function toString()
1627     {
1628         return sprintf("return_to %s not under trust_root %s",
1629                        $this->return_to, $this->trust_root);
1630     }
1631 }
1632
1633 /**
1634  * I handle requests for an OpenID server.
1635  *
1636  * Some types of requests (those which are not checkid requests) may
1637  * be handed to my {@link handleRequest} method, and I will take care
1638  * of it and return a response.
1639  *
1640  * For your convenience, I also provide an interface to {@link
1641  * Auth_OpenID_Decoder::decode()} and {@link
1642  * Auth_OpenID_SigningEncoder::encode()} through my methods {@link
1643  * decodeRequest} and {@link encodeResponse}.
1644  *
1645  * All my state is encapsulated in an {@link Auth_OpenID_OpenIDStore}.
1646  *
1647  * Example:
1648  *
1649  * <pre> $oserver = new Auth_OpenID_Server(Auth_OpenID_FileStore($data_path),
1650  *                                   "http://example.com/op");
1651  * $request = $oserver->decodeRequest();
1652  * if (in_array($request->mode, array('checkid_immediate',
1653  *                                    'checkid_setup'))) {
1654  *     if ($app->isAuthorized($request->identity, $request->trust_root)) {
1655  *         $response = $request->answer(true);
1656  *     } else if ($request->immediate) {
1657  *         $response = $request->answer(false);
1658  *     } else {
1659  *         $app->showDecidePage($request);
1660  *         return;
1661  *     }
1662  * } else {
1663  *     $response = $oserver->handleRequest($request);
1664  * }
1665  *
1666  * $webresponse = $oserver->encode($response);</pre>
1667  *
1668  * @package OpenID
1669  */
1670 class Auth_OpenID_Server {
1671     function Auth_OpenID_Server(&$store, $op_endpoint=null)
1672     {
1673         $this->store =& $store;
1674         $this->signatory =& new Auth_OpenID_Signatory($this->store);
1675         $this->encoder =& new Auth_OpenID_SigningEncoder($this->signatory);
1676         $this->decoder =& new Auth_OpenID_Decoder($this);
1677         $this->op_endpoint = $op_endpoint;
1678         $this->negotiator =& Auth_OpenID_getDefaultNegotiator();
1679     }
1680
1681     /**
1682      * Handle a request.  Given an {@link Auth_OpenID_Request} object,
1683      * call the appropriate {@link Auth_OpenID_Server} method to
1684      * process the request and generate a response.
1685      *
1686      * @param Auth_OpenID_Request $request An {@link Auth_OpenID_Request}
1687      * returned by {@link Auth_OpenID_Server::decodeRequest()}.
1688      *
1689      * @return Auth_OpenID_ServerResponse $response A response object
1690      * capable of generating a user-agent reply.
1691      */
1692     function handleRequest($request)
1693     {
1694         if (method_exists($this, "openid_" . $request->mode)) {
1695             $handler = array($this, "openid_" . $request->mode);
1696             return call_user_func($handler, $request);
1697         }
1698         return null;
1699     }
1700
1701     /**
1702      * The callback for 'check_authentication' messages.
1703      */
1704     function openid_check_authentication(&$request)
1705     {
1706         return $request->answer($this->signatory);
1707     }
1708
1709     /**
1710      * The callback for 'associate' messages.
1711      */
1712     function openid_associate(&$request)
1713     {
1714         $assoc_type = $request->assoc_type;
1715         $session_type = $request->session->session_type;
1716         if ($this->negotiator->isAllowed($assoc_type, $session_type)) {
1717             $assoc = $this->signatory->createAssociation(false,
1718                                                          $assoc_type);
1719             return $request->answer($assoc);
1720         } else {
1721             $message = sprintf('Association type %s is not supported with '.
1722                                'session type %s', $assoc_type, $session_type);
1723             list($preferred_assoc_type, $preferred_session_type) =
1724                 $this->negotiator->getAllowedType();
1725             return $request->answerUnsupported($message,
1726                                                $preferred_assoc_type,
1727                                                $preferred_session_type);
1728         }
1729     }
1730
1731     /**
1732      * Encodes as response in the appropriate format suitable for
1733      * sending to the user agent.
1734      */
1735     function encodeResponse(&$response)
1736     {
1737         return $this->encoder->encode($response);
1738     }
1739
1740     /**
1741      * Decodes a query args array into the appropriate
1742      * {@link Auth_OpenID_Request} object.
1743      */
1744     function decodeRequest($query=null)
1745     {
1746         if ($query === null) {
1747             $query = Auth_OpenID::getQuery();
1748         }
1749
1750         return $this->decoder->decode($query);
1751     }
1752 }
1753
1754 ?>