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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  //
  17  // This file is part of BasicLTI4Moodle
  18  //
  19  // BasicLTI4Moodle is an IMS BasicLTI (Basic Learning Tools for Interoperability)
  20  // consumer for Moodle 1.9 and Moodle 2.0. BasicLTI is a IMS Standard that allows web
  21  // based learning tools to be easily integrated in LMS as native ones. The IMS BasicLTI
  22  // specification is part of the IMS standard Common Cartridge 1.1 Sakai and other main LMS
  23  // are already supporting or going to support BasicLTI. This project Implements the consumer
  24  // for Moodle. Moodle is a Free Open source Learning Management System by Martin Dougiamas.
  25  // BasicLTI4Moodle is a project iniciated and leaded by Ludo(Marc Alier) and Jordi Piguillem
  26  // at the GESSI research group at UPC.
  27  // SimpleLTI consumer for Moodle is an implementation of the early specification of LTI
  28  // by Charles Severance (Dr Chuck) htp://dr-chuck.com , developed by Jordi Piguillem in a
  29  // Google Summer of Code 2008 project co-mentored by Charles Severance and Marc Alier.
  30  //
  31  // BasicLTI4Moodle is copyright 2009 by Marc Alier Forment, Jordi Piguillem and Nikolas Galanis
  32  // of the Universitat Politecnica de Catalunya http://www.upc.edu
  33  // Contact info: Marc Alier Forment granludo @ gmail.com or marc.alier @ upc.edu.
  34  
  35  namespace moodle\mod\lti; // Using a namespace as the basicLTI module imports classes with the same names.
  36  
  37  defined('MOODLE_INTERNAL') || die;
  38  
  39  require_once($CFG->dirroot . '/mod/lti/OAuth.php');
  40  require_once($CFG->dirroot . '/mod/lti/TrivialStore.php');
  41  
  42  function get_oauth_key_from_headers() {
  43      $requestheaders = OAuthUtil::get_headers();
  44  
  45      if (@substr($requestheaders['Authorization'], 0, 6) == "OAuth ") {
  46          $headerparameters = OAuthUtil::split_header($requestheaders['Authorization']);
  47  
  48          return format_string($headerparameters['oauth_consumer_key']);
  49      }
  50      return false;
  51  }
  52  
  53  function handle_oauth_body_post($oauthconsumerkey, $oauthconsumersecret, $body, $requestheaders = null) {
  54  
  55      if ($requestheaders == null) {
  56          $requestheaders = OAuthUtil::get_headers();
  57      }
  58  
  59      // Must reject application/x-www-form-urlencoded.
  60      if (isset($requestheaders['Content-type'])) {
  61          if ($requestheaders['Content-type'] == 'application/x-www-form-urlencoded' ) {
  62              throw new OAuthException("OAuth request body signing must not use application/x-www-form-urlencoded");
  63          }
  64      }
  65  
  66      if (@substr($requestheaders['Authorization'], 0, 6) == "OAuth ") {
  67          $headerparameters = OAuthUtil::split_header($requestheaders['Authorization']);
  68          $oauthbodyhash = $headerparameters['oauth_body_hash'];
  69      }
  70  
  71      if ( ! isset($oauthbodyhash)  ) {
  72          throw new OAuthException("OAuth request body signing requires oauth_body_hash body");
  73      }
  74  
  75      // Verify the message signature.
  76      $store = new TrivialOAuthDataStore();
  77      $store->add_consumer($oauthconsumerkey, $oauthconsumersecret);
  78  
  79      $server = new OAuthServer($store);
  80  
  81      $method = new OAuthSignatureMethod_HMAC_SHA1();
  82      $server->add_signature_method($method);
  83      $request = OAuthRequest::from_request();
  84  
  85      try {
  86          $server->verify_request($request);
  87      } catch (\Exception $e) {
  88          $message = $e->getMessage();
  89          throw new OAuthException("OAuth signature failed: " . $message);
  90      }
  91  
  92      $postdata = $body;
  93  
  94      $hash = base64_encode(sha1($postdata, true));
  95  
  96      if ( $hash != $oauthbodyhash ) {
  97          throw new OAuthException("OAuth oauth_body_hash mismatch");
  98      }
  99  
 100      return $postdata;
 101  }