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 $ltimessagehintenc = optional_param('lti_message_hint', '', PARAM_TEXT);
  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($nonce);
  55
  56 if (!$ok) {
  57     $error = 'invalid_request';
  58 }
  59 $ltimessagehint = json_decode($ltimessagehintenc);
  60 $ok = $ok && isset($ltimessagehint->launchid);
  61 if (!$ok) {
  62     $error = 'invalid_request';
  63     $desc = 'No launch id in LTI hint';
  64 }
  65 if ($ok && ($scope !== 'openid')) {
  66     $ok = false;
  67     $error = 'invalid_scope';
  68 }
  69 if ($ok && ($responsetype !== 'id_token')) {
  70     $ok = false;
  71     $error = 'unsupported_response_type';
  72 }
  73 if ($ok) {
  74     $launchid = $ltimessagehint->launchid;
  75     list($courseid, $typeid, $id, $messagetype, $foruserid, $titleb64, $textb64) = explode(',', $SESSION->$launchid, 7);
  76     unset($SESSION->$launchid);
  77     $config = lti_get_type_type_config($typeid);
  78     $ok = ($clientid === $config->lti_clientid);
  79     if (!$ok) {
  80         $error = 'unauthorized_client';
  81     }
  82 }
  83 if ($ok && ($loginhint !== $USER->id)) {
  84     $ok = false;
  85     $error = 'access_denied';
  86 }
  87
  88 // If we're unable to load up config; we cannot trust the redirect uri for POSTing to.
  89 if (empty($config)) {
  90     throw new moodle_exception('invalidrequest', 'error');
  91 } else {
  92     $uris = array_map("trim", explode("\n", $config->lti_redirectionuris));
  93     if (!in_array($redirecturi, $uris)) {
  94         throw new moodle_exception('invalidrequest', 'error');
  95     }
  96 }
  97 if ($ok) {
  98     if (isset($responsemode)) {
  99         $ok = ($responsemode === 'form_post');
 100         if (!$ok) {
 101             $error = 'invalid_request';
 102             $desc = 'Invalid response_mode';
 103         }
 104     } else {
 105         $ok = false;
 106         $error = 'invalid_request';
 107         $desc = 'Missing response_mode';
 108     }
 109 }
 110 if ($ok && !empty($prompt) && ($prompt !== 'none')) {
 111     $ok = false;
 112     $error = 'invalid_request';
 113     $desc = 'Invalid prompt';
 114 }
 115
 116 if ($ok) {
 117     $course = $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST);
 118     if ($id) {
 119         $cm = get_coursemodule_from_id('lti', $id, 0, false, MUST_EXIST);
 120         $context = context_module::instance($cm->id);
 121         require_login($course, true, $cm);
 122         require_capability('mod/lti:view', $context);
 123         $lti = $DB->get_record('lti', array('id' => $cm->instance), '*', MUST_EXIST);
 124         $lti->cmid = $cm->id;
 125         list($endpoint, $params) = lti_get_launch_data($lti, $nonce, $messagetype, $foruserid);
 126     } else {
 127         require_login($course);
 128         $context = context_course::instance($courseid);
 129         require_capability('moodle/course:manageactivities', $context);
 130         require_capability('mod/lti:addcoursetool', $context);
 131         // Set the return URL. We send the launch container along to help us avoid frames-within-frames when the user returns.
 132         $returnurlparams = [
 133             'course' => $courseid,
 134             'id' => $typeid,
 135             'sesskey' => sesskey()
 136         ];
 137         $returnurl = new \moodle_url('/mod/lti/contentitem_return.php', $returnurlparams);
 138         // Prepare the request.
 139         $title = base64_decode($titleb64);
 140         $text = base64_decode($textb64);
 141         $request = lti_build_content_item_selection_request($typeid, $course, $returnurl, $title, $text,
 142                                                             [], [], false, true, false, false, false, $nonce);
 143         $endpoint = $request->url;
 144         $params = $request->params;
 145     }
 146 } else {
 147     $params['error'] = $error;
 148     if (!empty($desc)) {
 149         $params['error_description'] = $desc;
 150     }
 151 }
 152 if (isset($state)) {
 153     $params['state'] = $state;
 154 }
 155 unset($SESSION->lti_message_hint);
 156 $r = '<form action="' . $redirecturi . "\" name=\"ltiAuthForm\" id=\"ltiAuthForm\" " .
 157      "method=\"post\" enctype=\"application/x-www-form-urlencoded\">\n";
 158 if (!empty($params)) {
 159     foreach ($params as $key => $value) {
 160         $key = htmlspecialchars($key, ENT_COMPAT);
 161         $value = htmlspecialchars($value, ENT_COMPAT);
 162         $r .= "  <input type=\"hidden\" name=\"{$key}\" value=\"{$value}\"/>\n";
 163     }
 164 }
 165 $r .= "</form>\n";
 166 $r .= "<script type=\"text/javascript\">\n" .
 167     "//<![CDATA[\n" .
 168     "document.ltiAuthForm.submit();\n" .
 169     "//]]>\n" .
 170     "</script>\n";
 171 echo $r;