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Differences Between: [Versions 310 and 402] [Versions 311 and 402] [Versions 39 and 402] [Versions 400 and 402] [Versions 401 and 402]

   1  <?php
   2  /**
   3   * An XML-RPC client
   4   *
   5   * @author  Donal McMullan  donal@catalyst.net.nz
   6   * @version 0.0.1
   7   * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
   8   * @package mnet
   9   */
  10  
  11  require_once $CFG->dirroot.'/mnet/lib.php';
  12  
  13  /**
  14   * Class representing an XMLRPC request against a remote machine
  15   */
  16  class mnet_xmlrpc_client {
  17  
  18      var $method   = '';
  19      var $params   = array();
  20      var $timeout  = 60;
  21      var $error    = array();
  22      var $response = '';
  23      var $mnet     = null;
  24  
  25      /**
  26       * Constructor
  27       */
  28      public function __construct() {
  29          // make sure we've got this set up before we try and do anything else
  30          $this->mnet = get_mnet_environment();
  31      }
  32  
  33      /**
  34       * Allow users to override the default timeout
  35       * @param   int $timeout    Request timeout in seconds
  36       * $return  bool            True if param is an integer or integer string
  37       */
  38      public function set_timeout($timeout) {
  39          if (!is_integer($timeout)) {
  40              if (is_numeric($timeout)) {
  41                  $this->timeout = (integer)$timeout;
  42                  return true;
  43              }
  44              return false;
  45          }
  46          $this->timeout = $timeout;
  47          return true;
  48      }
  49  
  50      /**
  51       * Set the path to the method or function we want to execute on the remote
  52       * machine. Examples:
  53       * mod/scorm/functionname
  54       * auth/mnet/methodname
  55       * In the case of auth and enrolment plugins, an object will be created and
  56       * the method on that object will be called
  57       */
  58      public function set_method($xmlrpcpath) {
  59          if (is_string($xmlrpcpath)) {
  60              $this->method = $xmlrpcpath;
  61              $this->params = array();
  62              return true;
  63          }
  64          $this->method = '';
  65          $this->params = array();
  66          return false;
  67      }
  68  
  69      /**
  70       * Add a parameter to the array of parameters.
  71       *
  72       * @param  string  $argument    A transport ID, as defined in lib.php
  73       * @param  string  $type        The argument type, can be one of:
  74       *                              i4
  75       *                              i8
  76       *                              int
  77       *                              double
  78       *                              string
  79       *                              boolean
  80       *                              datetime | dateTime.iso8601
  81       *                              base64
  82       *                              null
  83       *                              array
  84       *                              struct
  85       * @return bool                 True on success
  86       */
  87      public function add_param($argument, $type = 'string') {
  88  
  89          // Convert any use of the old 'datetime' to the correct 'dateTime.iso8601' one.
  90          $type = ($type === 'datetime' ? 'dateTime.iso8601' : $type);
  91  
  92          // BC fix, if some argument is array and comes as string, change type to array (sequentials)
  93          // or struct (associative).
  94          // This is the behavior of the encode_request() method from the xmlrpc extension.
  95          // Note that uses in core have been fixed, but there may be others using that.
  96          if (is_array($argument) && $type === 'string') {
  97              if (array_keys($argument) === range(0, count($argument) - 1)) {
  98                  $type = 'array';
  99              } else {
 100                  $type = 'struct';
 101              }
 102              mnet_debug('Incorrect ' . $type . ' param passed as string in mnet_xmlrpc_client->add_param(): ' .
 103                  json_encode($argument));
 104          }
 105  
 106          if (!isset(\PhpXmlRpc\Value::$xmlrpcTypes[$type])) { // Arrived here, still erong type? Let's stop.
 107              return false;
 108          }
 109  
 110          // If we are array or struct, we need to ensure that, recursively, all the elements are proper values.
 111          // or serialize, used later on send()  won't work with them. Encoder::encode() provides us with that.
 112          if ($type === 'array' || $type === 'struct') {
 113              $encoder = new \PhpXmlRpc\Encoder();
 114              $this->params[] = $encoder->encode($argument);
 115          } else {
 116              // Normal scalar case.
 117              $this->params[] = new \PhpXmlRpc\Value($argument, $type);
 118          }
 119          return true;
 120      }
 121  
 122      /**
 123       * Send the request to the server - decode and return the response
 124       *
 125       * @param  object   $mnet_peer      A mnet_peer object with details of the
 126       *                                  remote host we're connecting to
 127       * @param  bool     $rekey         The rekey attribute stops us from
 128       *                                  getting into a loop.
 129       * @return mixed                    A PHP variable, as returned by the
 130       */
 131      public function send($mnet_peer, bool $rekey = false) {
 132          global $CFG, $DB;
 133  
 134          if (!$this->permission_to_call($mnet_peer)) {
 135              mnet_debug("tried and wasn't allowed to call a method on $mnet_peer->wwwroot");
 136              return false;
 137          }
 138  
 139          $request = new \PhpXmlRpc\Request($this->method, $this->params);
 140          $requesttext = $request->serialize('utf-8');
 141  
 142          $signedrequest = mnet_sign_message($requesttext);
 143          $encryptedrequest = mnet_encrypt_message($signedrequest, $mnet_peer->public_key);
 144  
 145          $client = $this->prepare_http_request($mnet_peer);
 146  
 147          $timestamp_send    = time();
 148          mnet_debug("about to send the xmlrpc request");
 149          $response = $client->send($encryptedrequest, $this->timeout);
 150          mnet_debug("managed to complete a xmlrpc request");
 151          $timestamp_receive = time();
 152  
 153          if ($response->faultCode()) {
 154              $this->error[] = $response->faultCode() .':'. $response->faultString();
 155              return false;
 156          }
 157  
 158          $rawresponse = trim($response->value()); // Because MNet responses ARE NOT valid xmlrpc, don't try any PhpXmlRpc facility.
 159  
 160          $mnet_peer->touch();
 161  
 162          $crypt_parser = new mnet_encxml_parser();
 163          $crypt_parser->parse($rawresponse);
 164  
 165          // If we couldn't parse the message, or it doesn't seem to have encrypted contents,
 166          // give the most specific error msg available & return
 167          if (!$crypt_parser->payload_encrypted) {
 168              if (! empty($crypt_parser->remoteerror)) {
 169                  $this->error[] = '4: remote server error: ' . $crypt_parser->remoteerror;
 170              } else if (! empty($crypt_parser->error)) {
 171                  $crypt_parser_error = $crypt_parser->error[0];
 172  
 173                  $message = '3:XML Parse error in payload: '.$crypt_parser_error['string']."\n";
 174                  if (array_key_exists('lineno', $crypt_parser_error)) {
 175                      $message .= 'At line number: '.$crypt_parser_error['lineno']."\n";
 176                  }
 177                  if (array_key_exists('line', $crypt_parser_error)) {
 178                      $message .= 'Which reads: '.$crypt_parser_error['line']."\n";
 179                  }
 180                  $this->error[] = $message;
 181              } else {
 182                  $this->error[] = '1:Payload not encrypted ';
 183              }
 184  
 185              $crypt_parser->free_resource();
 186              return false;
 187          }
 188  
 189          $key  = array_pop($crypt_parser->cipher);
 190          $data = array_pop($crypt_parser->cipher);
 191  
 192          $crypt_parser->free_resource();
 193  
 194          // Initialize payload var
 195          $decryptedenvelope = '';
 196  
 197          //                                          &$decryptedenvelope
 198          $isOpen = openssl_open(base64_decode($data), $decryptedenvelope, base64_decode($key),
 199              $this->mnet->get_private_key(), 'RC4');
 200  
 201          if (!$isOpen) {
 202              // Decryption failed... let's try our archived keys
 203              $openssl_history = get_config('mnet', 'openssl_history');
 204              if(empty($openssl_history)) {
 205                  $openssl_history = array();
 206                  set_config('openssl_history', serialize($openssl_history), 'mnet');
 207              } else {
 208                  $openssl_history = unserialize($openssl_history);
 209              }
 210              foreach($openssl_history as $keyset) {
 211                  $keyresource = openssl_pkey_get_private($keyset['keypair_PEM']);
 212                  $isOpen      = openssl_open(base64_decode($data), $decryptedenvelope, base64_decode($key), $keyresource, 'RC4');
 213                  if ($isOpen) {
 214                      // It's an older code, sir, but it checks out
 215                      break;
 216                  }
 217              }
 218          }
 219  
 220          if (!$isOpen) {
 221              trigger_error("None of our keys could open the payload from host {$mnet_peer->wwwroot} with id {$mnet_peer->id}.");
 222              $this->error[] = '3:No key match';
 223              return false;
 224          }
 225  
 226          if (strpos(substr($decryptedenvelope, 0, 100), '<signedMessage>')) {
 227              $sig_parser = new mnet_encxml_parser();
 228              $sig_parser->parse($decryptedenvelope);
 229          } else {
 230              $this->error[] = '2:Payload not signed: ' . $decryptedenvelope;
 231              return false;
 232          }
 233  
 234          // Margin of error is the time it took the request to complete.
 235          $margin_of_error  = $timestamp_receive - $timestamp_send;
 236  
 237          // Guess the time gap between sending the request and the remote machine
 238          // executing the time() function. Marginally better than nothing.
 239          $hysteresis       = ($margin_of_error) / 2;
 240  
 241          $remote_timestamp = $sig_parser->remote_timestamp - $hysteresis;
 242          $time_offset      = $remote_timestamp - $timestamp_send;
 243          if ($time_offset > 0) {
 244              $threshold = get_config('mnet', 'drift_threshold');
 245              if(empty($threshold)) {
 246                  // We decided 15 seconds was a pretty good arbitrary threshold
 247                  // for time-drift between servers, but you can customize this in
 248                  // the config_plugins table. It's not advised though.
 249                  set_config('drift_threshold', 15, 'mnet');
 250                  $threshold = 15;
 251              }
 252              if ($time_offset > $threshold) {
 253                  $this->error[] = '6:Time gap with '.$mnet_peer->name.' ('.$time_offset.' seconds) is greater than the permitted maximum of '.$threshold.' seconds';
 254                  return false;
 255              }
 256          }
 257  
 258          $xmlrpcresponse = base64_decode($sig_parser->data_object);
 259          // Let's convert the xmlrpc back to PHP structure.
 260          $response = null;
 261          $encoder = new \PhpXmlRpc\Encoder();
 262          $oresponse = $encoder->decodeXML($xmlrpcresponse); // First, to internal PhpXmlRpc\Response structure.
 263          if ($oresponse instanceof \PhpXmlRpc\Response) {
 264              // Special handling of fault responses (because value() doesn't handle them properly).
 265              if ($oresponse->faultCode()) {
 266                  $response = ['faultCode' => $oresponse->faultCode(), 'faultString' => $oresponse->faultString()];
 267              } else {
 268                  $response = $encoder->decode($oresponse->value()); // Normal Response conversion to PHP.
 269              }
 270          } else {
 271              // Maybe this is just a param, let's convert it too.
 272              $response = $encoder->decode($oresponse);
 273          }
 274          $this->response = $response;
 275  
 276          // xmlrpc errors are pushed onto the $this->error stack
 277          if (is_array($this->response) && array_key_exists('faultCode', $this->response)) {
 278              // The faultCode 7025 means we tried to connect with an old SSL key
 279              // The faultString is the new key - let's save it and try again
 280              // The rekey attribute stops us from getting into a loop
 281              if($this->response['faultCode'] == 7025 && empty($rekey)) {
 282                  mnet_debug('recieved an old-key fault, so trying to get the new key and update our records');
 283                  // If the new certificate doesn't come thru clean_param() unmolested, error out
 284                  if($this->response['faultString'] != clean_param($this->response['faultString'], PARAM_PEM)) {
 285                      $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
 286                  }
 287                  $record                     = new stdClass();
 288                  $record->id                 = $mnet_peer->id;
 289                  $record->public_key         = $this->response['faultString'];
 290                  $details                    = openssl_x509_parse($record->public_key);
 291                  if(!isset($details['validTo_time_t'])) {
 292                      $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
 293                  }
 294                  $record->public_key_expires = $details['validTo_time_t'];
 295                  $DB->update_record('mnet_host', $record);
 296  
 297                  // Create a new peer object populated with the new info & try re-sending the request
 298                  $rekeyed_mnet_peer = new mnet_peer();
 299                  $rekeyed_mnet_peer->set_id($record->id);
 300                  return $this->send($rekeyed_mnet_peer, true); // Re-send mnet_peer with the new key.
 301              }
 302              if (!empty($CFG->mnet_rpcdebug)) {
 303                  if (get_string_manager()->string_exists('error'.$this->response['faultCode'], 'mnet')) {
 304                      $guidance = get_string('error'.$this->response['faultCode'], 'mnet');
 305                  } else {
 306                      $guidance = '';
 307                  }
 308              } else {
 309                  $guidance = '';
 310              }
 311              $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'] ."\n".$guidance;
 312          }
 313  
 314          // ok, it's signed, but is it signed with the right certificate ?
 315          // do this *after* we check for an out of date key
 316          $verified = openssl_verify($xmlrpcresponse, base64_decode($sig_parser->signature), $mnet_peer->public_key);
 317          if ($verified != 1) {
 318              $this->error[] = 'Invalid signature';
 319          }
 320  
 321          return empty($this->error);
 322      }
 323  
 324      /**
 325       * Check that we are permitted to call method on specified peer
 326       *
 327       * @param object $mnet_peer A mnet_peer object with details of the remote host we're connecting to
 328       * @return bool True if we permit calls to method on specified peer, False otherwise.
 329       */
 330      public function permission_to_call($mnet_peer) {
 331          global $DB, $CFG, $USER;
 332  
 333          // Executing any system method is permitted.
 334          $system_methods = array('system/listMethods', 'system/methodSignature', 'system/methodHelp', 'system/listServices');
 335          if (in_array($this->method, $system_methods) ) {
 336              return true;
 337          }
 338  
 339          $hostids = array($mnet_peer->id);
 340          if (!empty($CFG->mnet_all_hosts_id)) {
 341              $hostids[] = $CFG->mnet_all_hosts_id;
 342          }
 343          // At this point, we don't care if the remote host implements the
 344          // method we're trying to call. We just want to know that:
 345          // 1. The method belongs to some service, as far as OUR host knows
 346          // 2. We are allowed to subscribe to that service on this mnet_peer
 347  
 348          list($hostidsql, $hostidparams) = $DB->get_in_or_equal($hostids);
 349  
 350          $sql = "SELECT r.id
 351                    FROM {mnet_remote_rpc} r
 352              INNER JOIN {mnet_remote_service2rpc} s2r ON s2r.rpcid = r.id
 353              INNER JOIN {mnet_host2service} h2s ON h2s.serviceid = s2r.serviceid
 354                   WHERE r.xmlrpcpath = ?
 355                         AND h2s.subscribe = ?
 356                         AND h2s.hostid $hostidsql";
 357  
 358          $params = array($this->method, 1);
 359          $params = array_merge($params, $hostidparams);
 360  
 361          if ($DB->record_exists_sql($sql, $params)) {
 362              return true;
 363          }
 364  
 365          $this->error[] = '7:User with ID '. $USER->id .
 366                           ' attempted to call unauthorised method '.
 367                           $this->method.' on host '.
 368                           $mnet_peer->wwwroot;
 369          return false;
 370      }
 371  
 372      /**
 373       * Generate a \PhpXmlRpc\Client handle and prepare it for sending to an mnet host
 374       *
 375       * @param object $mnet_peer A mnet_peer object with details of the remote host the request will be sent to
 376       * @return \PhpXmlRpc\Client handle - the almost-ready-to-send http request
 377       */
 378      public function prepare_http_request ($mnet_peer) {
 379          $uri = $mnet_peer->wwwroot . $mnet_peer->application->xmlrpc_server_url;
 380  
 381          // Instantiate the xmlrpc client to be used for the client request
 382          // and configure it the way we want.
 383          $client = new \PhpXmlRpc\Client($uri);
 384          $client->setUseCurl(\PhpXmlRpc\Client::USE_CURL_ALWAYS);
 385          $client->setUserAgent('Moodle');
 386          $client->return_type = 'xml'; // Because MNet responses ARE NOT valid xmlrpc, don't try any validation.
 387  
 388          // TODO: Link this to DEBUG DEVELOPER or with MNET debugging...
 389          // $client->setdebug(1); // See a good number of complete requests and responses.
 390  
 391          $verifyhost = 0;
 392          $verifypeer = false;
 393          if ($mnet_peer->sslverification == mnet_peer::SSL_HOST_AND_PEER) {
 394              $verifyhost = 2;
 395              $verifypeer = true;
 396          } else if ($mnet_peer->sslverification == mnet_peer::SSL_HOST) {
 397              $verifyhost = 2;
 398          }
 399          $client->setSSLVerifyHost($verifyhost);
 400          $client->setSSLVerifyPeer($verifypeer);
 401  
 402          return $client;
 403      }
 404  }