[Summary view]

Differences Between: [Versions 310 and 311] [Versions 311 and 401] [Versions 311 and 402] [Versions 311 and 403] [Versions 39 and 311]

   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       * Old syntax of class constructor. Deprecated in PHP7.
  35       *
  36       * @deprecated since Moodle 3.1
  37       */
  38      public function mnet_xmlrpc_client() {
  39          debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
  40          self::__construct();
  41      }
  42  
  43      /**
  44       * Allow users to override the default timeout
  45       * @param   int $timeout    Request timeout in seconds
  46       * $return  bool            True if param is an integer or integer string
  47       */
  48      function set_timeout($timeout) {
  49          if (!is_integer($timeout)) {
  50              if (is_numeric($timeout)) {
  51                  $this->timeout = (integer)$timeout;
  52                  return true;
  53              }
  54              return false;
  55          }
  56          $this->timeout = $timeout;
  57          return true;
  58      }
  59  
  60      /**
  61       * Set the path to the method or function we want to execute on the remote
  62       * machine. Examples:
  63       * mod/scorm/functionname
  64       * auth/mnet/methodname
  65       * In the case of auth and enrolment plugins, an object will be created and
  66       * the method on that object will be called
  67       */
  68      function set_method($xmlrpcpath) {
  69          if (is_string($xmlrpcpath)) {
  70              $this->method = $xmlrpcpath;
  71              $this->params = array();
  72              return true;
  73          }
  74          $this->method = '';
  75          $this->params = array();
  76          return false;
  77      }
  78  
  79      /**
  80       * Add a parameter to the array of parameters.
  81       *
  82       * @param  string  $argument    A transport ID, as defined in lib.php
  83       * @param  string  $type        The argument type, can be one of:
  84       *                              none
  85       *                              empty
  86       *                              base64
  87       *                              boolean
  88       *                              datetime
  89       *                              double
  90       *                              int
  91       *                              string
  92       *                              array
  93       *                              struct
  94       *                              In its weakly-typed wisdom, PHP will (currently)
  95       *                              ignore everything except datetime and base64
  96       * @return bool                 True on success
  97       */
  98      function add_param($argument, $type = 'string') {
  99  
 100          $allowed_types = array('none',
 101                                 'empty',
 102                                 'base64',
 103                                 'boolean',
 104                                 'datetime',
 105                                 'double',
 106                                 'int',
 107                                 'i4',
 108                                 'string',
 109                                 'array',
 110                                 'struct');
 111          if (!in_array($type, $allowed_types)) {
 112              return false;
 113          }
 114  
 115          if ($type != 'datetime' && $type != 'base64') {
 116              $this->params[] = $argument;
 117              return true;
 118          }
 119  
 120          // Note weirdness - The type of $argument gets changed to an object with
 121          // value and type properties.
 122          // bool xmlrpc_set_type ( string &value, string type )
 123          xmlrpc_set_type($argument, $type);
 124          $this->params[] = $argument;
 125          return true;
 126      }
 127  
 128      /**
 129       * Send the request to the server - decode and return the response
 130       *
 131       * @param  object   $mnet_peer      A mnet_peer object with details of the
 132       *                                  remote host we're connecting to
 133       * @return mixed                    A PHP variable, as returned by the
 134       *                                  remote function
 135       */
 136      function send($mnet_peer) {
 137          global $CFG, $DB;
 138  
 139  
 140          if (!$this->permission_to_call($mnet_peer)) {
 141              mnet_debug("tried and wasn't allowed to call a method on $mnet_peer->wwwroot");
 142              return false;
 143          }
 144  
 145          $this->requesttext = xmlrpc_encode_request($this->method, $this->params, array("encoding" => "utf-8", "escaping" => "markup"));
 146          $this->signedrequest = mnet_sign_message($this->requesttext);
 147          $this->encryptedrequest = mnet_encrypt_message($this->signedrequest, $mnet_peer->public_key);
 148  
 149          $httprequest = $this->prepare_http_request($mnet_peer);
 150          curl_setopt($httprequest, CURLOPT_POSTFIELDS, $this->encryptedrequest);
 151  
 152          $timestamp_send    = time();
 153          mnet_debug("about to send the curl request");
 154          $this->rawresponse = curl_exec($httprequest);
 155          mnet_debug("managed to complete a curl request");
 156          $timestamp_receive = time();
 157  
 158          if ($this->rawresponse === false) {
 159              $this->error[] = curl_errno($httprequest) .':'. curl_error($httprequest);
 160              return false;
 161          }
 162          curl_close($httprequest);
 163  
 164          $this->rawresponse = trim($this->rawresponse);
 165  
 166          $mnet_peer->touch();
 167  
 168          $crypt_parser = new mnet_encxml_parser();
 169          $crypt_parser->parse($this->rawresponse);
 170  
 171          // If we couldn't parse the message, or it doesn't seem to have encrypted contents,
 172          // give the most specific error msg available & return
 173          if (!$crypt_parser->payload_encrypted) {
 174              if (! empty($crypt_parser->remoteerror)) {
 175                  $this->error[] = '4: remote server error: ' . $crypt_parser->remoteerror;
 176              } else if (! empty($crypt_parser->error)) {
 177                  $crypt_parser_error = $crypt_parser->error[0];
 178  
 179                  $message = '3:XML Parse error in payload: '.$crypt_parser_error['string']."\n";
 180                  if (array_key_exists('lineno', $crypt_parser_error)) {
 181                      $message .= 'At line number: '.$crypt_parser_error['lineno']."\n";
 182                  }
 183                  if (array_key_exists('line', $crypt_parser_error)) {
 184                      $message .= 'Which reads: '.$crypt_parser_error['line']."\n";
 185                  }
 186                  $this->error[] = $message;
 187              } else {
 188                  $this->error[] = '1:Payload not encrypted ';
 189              }
 190  
 191              $crypt_parser->free_resource();
 192              return false;
 193          }
 194  
 195          $key  = array_pop($crypt_parser->cipher);
 196          $data = array_pop($crypt_parser->cipher);
 197  
 198          $crypt_parser->free_resource();
 199  
 200          // Initialize payload var
 201          $decryptedenvelope = '';
 202  
 203          //                                          &$decryptedenvelope
 204          $isOpen = openssl_open(base64_decode($data), $decryptedenvelope, base64_decode($key),
 205              $this->mnet->get_private_key(), 'RC4');
 206  
 207          if (!$isOpen) {
 208              // Decryption failed... let's try our archived keys
 209              $openssl_history = get_config('mnet', 'openssl_history');
 210              if(empty($openssl_history)) {
 211                  $openssl_history = array();
 212                  set_config('openssl_history', serialize($openssl_history), 'mnet');
 213              } else {
 214                  $openssl_history = unserialize($openssl_history);
 215              }
 216              foreach($openssl_history as $keyset) {
 217                  $keyresource = openssl_pkey_get_private($keyset['keypair_PEM']);
 218                  $isOpen      = openssl_open(base64_decode($data), $decryptedenvelope, base64_decode($key), $keyresource, 'RC4');
 219                  if ($isOpen) {
 220                      // It's an older code, sir, but it checks out
 221                      break;
 222                  }
 223              }
 224          }
 225  
 226          if (!$isOpen) {
 227              trigger_error("None of our keys could open the payload from host {$mnet_peer->wwwroot} with id {$mnet_peer->id}.");
 228              $this->error[] = '3:No key match';
 229              return false;
 230          }
 231  
 232          if (strpos(substr($decryptedenvelope, 0, 100), '<signedMessage>')) {
 233              $sig_parser = new mnet_encxml_parser();
 234              $sig_parser->parse($decryptedenvelope);
 235          } else {
 236              $this->error[] = '2:Payload not signed: ' . $decryptedenvelope;
 237              return false;
 238          }
 239  
 240          // Margin of error is the time it took the request to complete.
 241          $margin_of_error  = $timestamp_receive - $timestamp_send;
 242  
 243          // Guess the time gap between sending the request and the remote machine
 244          // executing the time() function. Marginally better than nothing.
 245          $hysteresis       = ($margin_of_error) / 2;
 246  
 247          $remote_timestamp = $sig_parser->remote_timestamp - $hysteresis;
 248          $time_offset      = $remote_timestamp - $timestamp_send;
 249          if ($time_offset > 0) {
 250              $threshold = get_config('mnet', 'drift_threshold');
 251              if(empty($threshold)) {
 252                  // We decided 15 seconds was a pretty good arbitrary threshold
 253                  // for time-drift between servers, but you can customize this in
 254                  // the config_plugins table. It's not advised though.
 255                  set_config('drift_threshold', 15, 'mnet');
 256                  $threshold = 15;
 257              }
 258              if ($time_offset > $threshold) {
 259                  $this->error[] = '6:Time gap with '.$mnet_peer->name.' ('.$time_offset.' seconds) is greater than the permitted maximum of '.$threshold.' seconds';
 260                  return false;
 261              }
 262          }
 263  
 264          $this->xmlrpcresponse = base64_decode($sig_parser->data_object);
 265          $this->response       = xmlrpc_decode($this->xmlrpcresponse);
 266  
 267          // xmlrpc errors are pushed onto the $this->error stack
 268          if (is_array($this->response) && array_key_exists('faultCode', $this->response)) {
 269              // The faultCode 7025 means we tried to connect with an old SSL key
 270              // The faultString is the new key - let's save it and try again
 271              // The re_key attribute stops us from getting into a loop
 272              if($this->response['faultCode'] == 7025 && empty($mnet_peer->re_key)) {
 273                  mnet_debug('recieved an old-key fault, so trying to get the new key and update our records');
 274                  // If the new certificate doesn't come thru clean_param() unmolested, error out
 275                  if($this->response['faultString'] != clean_param($this->response['faultString'], PARAM_PEM)) {
 276                      $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
 277                  }
 278                  $record                     = new stdClass();
 279                  $record->id                 = $mnet_peer->id;
 280                  $record->public_key         = $this->response['faultString'];
 281                  $details                    = openssl_x509_parse($record->public_key);
 282                  if(!isset($details['validTo_time_t'])) {
 283                      $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'];
 284                  }
 285                  $record->public_key_expires = $details['validTo_time_t'];
 286                  $DB->update_record('mnet_host', $record);
 287  
 288                  // Create a new peer object populated with the new info & try re-sending the request
 289                  $rekeyed_mnet_peer = new mnet_peer();
 290                  $rekeyed_mnet_peer->set_id($record->id);
 291                  $rekeyed_mnet_peer->re_key = true;
 292                  return $this->send($rekeyed_mnet_peer);
 293              }
 294              if (!empty($CFG->mnet_rpcdebug)) {
 295                  if (get_string_manager()->string_exists('error'.$this->response['faultCode'], 'mnet')) {
 296                      $guidance = get_string('error'.$this->response['faultCode'], 'mnet');
 297                  } else {
 298                      $guidance = '';
 299                  }
 300              } else {
 301                  $guidance = '';
 302              }
 303              $this->error[] = $this->response['faultCode'] . " : " . $this->response['faultString'] ."\n".$guidance;
 304          }
 305  
 306          // ok, it's signed, but is it signed with the right certificate ?
 307          // do this *after* we check for an out of date key
 308          $verified = openssl_verify($this->xmlrpcresponse, base64_decode($sig_parser->signature), $mnet_peer->public_key);
 309          if ($verified != 1) {
 310              $this->error[] = 'Invalid signature';
 311          }
 312  
 313          return empty($this->error);
 314      }
 315  
 316      /**
 317       * Check that we are permitted to call method on specified peer
 318       *
 319       * @param object $mnet_peer A mnet_peer object with details of the remote host we're connecting to
 320       * @return bool True if we permit calls to method on specified peer, False otherwise.
 321       */
 322  
 323      function permission_to_call($mnet_peer) {
 324          global $DB, $CFG, $USER;
 325  
 326          // Executing any system method is permitted.
 327          $system_methods = array('system/listMethods', 'system/methodSignature', 'system/methodHelp', 'system/listServices');
 328          if (in_array($this->method, $system_methods) ) {
 329              return true;
 330          }
 331  
 332          $hostids = array($mnet_peer->id);
 333          if (!empty($CFG->mnet_all_hosts_id)) {
 334              $hostids[] = $CFG->mnet_all_hosts_id;
 335          }
 336          // At this point, we don't care if the remote host implements the
 337          // method we're trying to call. We just want to know that:
 338          // 1. The method belongs to some service, as far as OUR host knows
 339          // 2. We are allowed to subscribe to that service on this mnet_peer
 340  
 341          list($hostidsql, $hostidparams) = $DB->get_in_or_equal($hostids);
 342  
 343          $sql = "SELECT r.id
 344                    FROM {mnet_remote_rpc} r
 345              INNER JOIN {mnet_remote_service2rpc} s2r ON s2r.rpcid = r.id
 346              INNER JOIN {mnet_host2service} h2s ON h2s.serviceid = s2r.serviceid
 347                   WHERE r.xmlrpcpath = ?
 348                         AND h2s.subscribe = ?
 349                         AND h2s.hostid $hostidsql";
 350  
 351          $params = array($this->method, 1);
 352          $params = array_merge($params, $hostidparams);
 353  
 354          if ($DB->record_exists_sql($sql, $params)) {
 355              return true;
 356          }
 357  
 358          $this->error[] = '7:User with ID '. $USER->id .
 359                           ' attempted to call unauthorised method '.
 360                           $this->method.' on host '.
 361                           $mnet_peer->wwwroot;
 362          return false;
 363      }
 364  
 365      /**
 366       * Generate a curl handle and prepare it for sending to an mnet host
 367       *
 368       * @param object $mnet_peer A mnet_peer object with details of the remote host the request will be sent to
 369       * @return cURL handle - the almost-ready-to-send http request
 370       */
 371      function prepare_http_request ($mnet_peer) {
 372          $this->uri = $mnet_peer->wwwroot . $mnet_peer->application->xmlrpc_server_url;
 373  
 374          // Initialize request the target URL
 375          $httprequest = curl_init($this->uri);
 376          curl_setopt($httprequest, CURLOPT_TIMEOUT, $this->timeout);
 377          curl_setopt($httprequest, CURLOPT_RETURNTRANSFER, true);
 378          curl_setopt($httprequest, CURLOPT_POST, true);
 379          curl_setopt($httprequest, CURLOPT_USERAGENT, 'Moodle');
 380          curl_setopt($httprequest, CURLOPT_HTTPHEADER, array("Content-Type: text/xml charset=UTF-8"));
 381  
 382          $verifyhost = 0;
 383          $verifypeer = false;
 384          if ($mnet_peer->sslverification == mnet_peer::SSL_HOST_AND_PEER) {
 385              $verifyhost = 2;
 386              $verifypeer = true;
 387          } else if ($mnet_peer->sslverification == mnet_peer::SSL_HOST) {
 388              $verifyhost = 2;
 389          }
 390          curl_setopt($httprequest, CURLOPT_SSL_VERIFYHOST, $verifyhost);
 391          curl_setopt($httprequest, CURLOPT_SSL_VERIFYPEER, $verifypeer);
 392          return $httprequest;
 393      }
 394  }