mod/lti/auth.php

   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 /**
  18  * This file responds to a login authentication request
  19  *
  20  * @package    mod_lti
  21  * @copyright  2019 Stephen Vickers
  22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 require_once(__DIR__ . '/../../config.php');
  26 require_once($CFG->dirroot . '/mod/lti/locallib.php');
  27 global $_POST, $_SERVER;
  28
  29 if (!isloggedin() && empty($_POST['repost'])) {
  30     header_remove("Set-Cookie");
  31     $PAGE->set_pagelayout('popup');
  32     $PAGE->set_context(context_system::instance());
  33     $output = $PAGE->get_renderer('mod_lti');
  34     $page = new \mod_lti\output\repost_crosssite_page($_SERVER['REQUEST_URI'], $_POST);
  35     echo $output->header();
  36     echo $output->render($page);
  37     echo $output->footer();
  38     return;
  39 }
  40
  41 $scope = optional_param('scope', '', PARAM_TEXT);
  42 $responsetype = optional_param('response_type', '', PARAM_TEXT);
  43 $clientid = optional_param('client_id', '', PARAM_TEXT);
  44 $redirecturi = optional_param('redirect_uri', '', PARAM_URL);
  45 $loginhint = optional_param('login_hint', '', PARAM_TEXT);
  46 $ltimessagehint = optional_param('lti_message_hint', 0, PARAM_INT);
  47 $state = optional_param('state', '', PARAM_TEXT);
  48 $responsemode = optional_param('response_mode', '', PARAM_TEXT);
  49 $nonce = optional_param('nonce', '', PARAM_TEXT);
  50 $prompt = optional_param('prompt', '', PARAM_TEXT);
  51
  52 $ok = !empty($scope) && !empty($responsetype) && !empty($clientid) &&
  53       !empty($redirecturi) && !empty($loginhint) &&
  54       !empty($nonce) && !empty($SESSION->lti_message_hint);
  55
  56 if (!$ok) {
  57     $error = 'invalid_request';
  58 }
  59 if ($ok && ($scope !== 'openid')) {
  60     $ok = false;
  61     $error = 'invalid_scope';
  62 }
  63 if ($ok && ($responsetype !== 'id_token')) {
  64     $ok = false;
  65     $error = 'unsupported_response_type';
  66 }
  67 if ($ok) {
  68     list($courseid, $typeid, $id, $titleb64, $textb64) = explode(',', $SESSION->lti_message_hint, 5);
  69     $ok = ($id !== $ltimessagehint);
  70     if (!$ok) {
  71         $error = 'invalid_request';
  72     } else {
  73         $config = lti_get_type_type_config($typeid);
  74         $ok = ($clientid === $config->lti_clientid);
  75         if (!$ok) {
  76             $error = 'unauthorized_client';
  77         }
  78     }
  79 }
  80 if ($ok && ($loginhint !== $USER->id)) {
  81     $ok = false;
  82     $error = 'access_denied';
  83 }
  84
  85 // If we're unable to load up config; we cannot trust the redirect uri for POSTing to.
  86 if (empty($config)) {
  87     throw new moodle_exception('invalidrequest', 'error');
  88 } else {
  89     $uris = array_map("trim", explode("\n", $config->lti_redirectionuris));
  90     if (!in_array($redirecturi, $uris)) {
  91         throw new moodle_exception('invalidrequest', 'error');
  92     }
  93 }
  94 if ($ok) {
  95     if (isset($responsemode)) {
  96         $ok = ($responsemode === 'form_post');
  97         if (!$ok) {
  98             $error = 'invalid_request';
  99             $desc = 'Invalid response_mode';
 100         }
 101     } else {
 102         $ok = false;
 103         $error = 'invalid_request';
 104         $desc = 'Missing response_mode';
 105     }
 106 }
 107 if ($ok && !empty($prompt) && ($prompt !== 'none')) {
 108     $ok = false;
 109     $error = 'invalid_request';
 110     $desc = 'Invalid prompt';
 111 }
 112
 113 if ($ok) {
 114     $course = $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST);
 115     if ($id) {
 116         $cm = get_coursemodule_from_id('lti', $id, 0, false, MUST_EXIST);
 117         $context = context_module::instance($cm->id);
 118         require_login($course, true, $cm);
 119         require_capability('mod/lti:view', $context);
 120         $lti = $DB->get_record('lti', array('id' => $cm->instance), '*', MUST_EXIST);
 121         $lti->cmid = $cm->id;
 122         list($endpoint, $params) = lti_get_launch_data($lti, $nonce);
 123     } else {
 124         require_login($course);
 125         $context = context_course::instance($courseid);
 126         require_capability('moodle/course:manageactivities', $context);
 127         require_capability('mod/lti:addcoursetool', $context);
 128         // Set the return URL. We send the launch container along to help us avoid frames-within-frames when the user returns.
 129         $returnurlparams = [
 130             'course' => $courseid,
 131             'id' => $typeid,
 132             'sesskey' => sesskey()
 133         ];
 134         $returnurl = new \moodle_url('/mod/lti/contentitem_return.php', $returnurlparams);
 135         // Prepare the request.
 136         $title = base64_decode($titleb64);
 137         $text = base64_decode($textb64);
 138         $request = lti_build_content_item_selection_request($typeid, $course, $returnurl, $title, $text,
 139                                                             [], [], false, true, false, false, false, $nonce);
 140         $endpoint = $request->url;
 141         $params = $request->params;
 142     }
 143 } else {
 144     $params['error'] = $error;
 145     if (!empty($desc)) {
 146         $params['error_description'] = $desc;
 147     }
 148 }
 149 if (isset($state)) {
 150     $params['state'] = $state;
 151 }
 152 unset($SESSION->lti_message_hint);
 153 $r = '<form action="' . $redirecturi . "\" name=\"ltiAuthForm\" id=\"ltiAuthForm\" " .
 154      "method=\"post\" enctype=\"application/x-www-form-urlencoded\">\n";
 155 if (!empty($params)) {
 156     foreach ($params as $key => $value) {
 157         $key = htmlspecialchars($key);
 158         $value = htmlspecialchars($value);
 159         $r .= "  <input type=\"hidden\" name=\"{$key}\" value=\"{$value}\"/>\n";
 160     }
 161 }
 162 $r .= "</form>\n";
 163 $r .= "<script type=\"text/javascript\">\n" .
 164     "//<![CDATA[\n" .
 165     "document.ltiAuthForm.submit();\n" .
 166     "//]]>\n" .
 167     "</script>\n";
 168 echo $r;