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See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

> use mod_quiz\local\access_rule_base; /** > use mod_quiz\quiz_attempt; * Implementation of the quizaccess_seb plugin. > use quizaccess_seb\seb_access_manager; * > use quizaccess_seb\seb_quiz_settings; * @package quizaccess_seb > use quizaccess_seb\settings_provider; * @author Andrew Madden <andrewmadden@catalyst-au.net> > use quizaccess_seb\event\access_prevented; * @author Dmitrii Metelkin <dmitriim@catalyst-au.net> >
* @copyright 2019 Catalyst IT * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */
> class quizaccess_seb extends access_rule_base {
< use quizaccess_seb\access_manager; < use quizaccess_seb\quiz_settings; < use quizaccess_seb\settings_provider; < use \quizaccess_seb\event\access_prevented; < < defined('MOODLE_INTERNAL') || die(); < < global $CFG; < require_once($CFG->dirroot . '/mod/quiz/accessrule/accessrulebase.php'); < < /** < * Implementation of the quizaccess_seb plugin. < * < * @copyright 2020 Catalyst IT < * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later < */ < class quizaccess_seb extends quiz_access_rule_base { < < /** @var access_manager $accessmanager Instance to manage the access to the quiz for this plugin. */
> /** @var seb_access_manager $accessmanager Instance to manage the access to the quiz for this plugin. */
private $accessmanager; /** * Create an instance of this rule for a particular quiz. *
< * @param quiz $quizobj information about the quiz in question.
> * @param \mod_quiz\quiz_settings $quizobj information about the quiz in question.
* @param int $timenow the time that should be considered as 'now'.
< * @param access_manager $accessmanager the quiz accessmanager.
> * @param seb_access_manager $accessmanager the quiz accessmanager.
*/
< public function __construct(quiz $quizobj, int $timenow, access_manager $accessmanager) {
> public function __construct(\mod_quiz\quiz_settings $quizobj, int $timenow, seb_access_manager $accessmanager) {
parent::__construct($quizobj, $timenow); $this->accessmanager = $accessmanager; } /** * Return an appropriately configured instance of this rule, if it is applicable * to the given quiz, otherwise return null. *
< * @param quiz $quizobj information about the quiz in question.
> * @param \mod_quiz\quiz_settings $quizobj information about the quiz in question.
* @param int $timenow the time that should be considered as 'now'. * @param bool $canignoretimelimits whether the current user is exempt from * time limits by the mod/quiz:ignoretimelimits capability.
< * @return quiz_access_rule_base|null the rule, if applicable, else null.
> * @return access_rule_base|null the rule, if applicable, else null.
*/
< public static function make (quiz $quizobj, $timenow, $canignoretimelimits) { < $accessmanager = new access_manager($quizobj);
> public static function make(\mod_quiz\quiz_settings $quizobj, $timenow, $canignoretimelimits) { > $accessmanager = new seb_access_manager($quizobj);
// If Safe Exam Browser is not required, this access rule is not applicable. if (!$accessmanager->seb_required()) { return null; } return new self($quizobj, $timenow, $accessmanager); } /** * Add any fields that this rule requires to the quiz settings form. This * method is called from {@link mod_quiz_mod_form::definition()}, while the * security section is being built. * * @param mod_quiz_mod_form $quizform the quiz settings form that is being built. * @param MoodleQuickForm $mform the wrapped MoodleQuickForm. */ public static function add_settings_form_fields(mod_quiz_mod_form $quizform, MoodleQuickForm $mform) { settings_provider::add_seb_settings_fields($quizform, $mform); } /** * Validate the data from any form fields added using {@link add_settings_form_fields()}. * * @param array $errors the errors found so far. * @param array $data the submitted form data. * @param array $files information about any uploaded files. * @param mod_quiz_mod_form $quizform the quiz form object. * @return array $errors the updated $errors array. */ public static function validate_settings_form_fields(array $errors, array $data, $files, mod_quiz_mod_form $quizform) : array { $quizid = $data['instance']; $cmid = $data['coursemodule']; $context = $quizform->get_context(); if (!settings_provider::can_configure_seb($context)) { return $errors; } if (settings_provider::is_seb_settings_locked($quizid)) { return $errors; } if (settings_provider::is_conflicting_permissions($context)) { return $errors; } $settings = settings_provider::filter_plugin_settings((object) $data); // Validate basic settings using persistent class.
< $quizsettings = (new quiz_settings())->from_record($settings);
> $quizsettings = (new seb_quiz_settings())->from_record($settings);
// Set non-form fields. $quizsettings->set('quizid', $quizid); $quizsettings->set('cmid', $cmid); $quizsettings->validate(); // Add any errors to list. foreach ($quizsettings->get_errors() as $name => $error) { $name = settings_provider::add_prefix($name); // Re-add prefix to match form element. $errors[$name] = $error->out(); } // Edge case for filemanager_sebconfig. if ($quizsettings->get('requiresafeexambrowser') == settings_provider::USE_SEB_UPLOAD_CONFIG) { $errorvalidatefile = settings_provider::validate_draftarea_configfile($data['filemanager_sebconfigfile']); if (!empty($errorvalidatefile)) { $errors['filemanager_sebconfigfile'] = $errorvalidatefile; } } // Edge case to force user to select a template. if ($quizsettings->get('requiresafeexambrowser') == settings_provider::USE_SEB_TEMPLATE) { if (empty($data['seb_templateid'])) { $errors['seb_templateid'] = get_string('invalidtemplate', 'quizaccess_seb'); } } if ($quizsettings->get('requiresafeexambrowser') != settings_provider::USE_SEB_NO) { // Global settings may be active which require a quiz password to be set if using SEB. if (!empty(get_config('quizaccess_seb', 'quizpasswordrequired')) && empty($data['quizpassword'])) { $errors['quizpassword'] = get_string('passwordnotset', 'quizaccess_seb'); } } return $errors; } /** * Save any submitted settings when the quiz settings form is submitted. This * is called from {@link quiz_after_add_or_update()} in lib.php. *
< * @param object $quiz the data from the quiz form, including $quiz->id
> * @param stdClass $quiz the data from the quiz form, including $quiz->id
* which is the id of the quiz being saved. */ public static function save_settings($quiz) { $context = context_module::instance($quiz->coursemodule); if (!settings_provider::can_configure_seb($context)) { return; } if (settings_provider::is_seb_settings_locked($quiz->id)) { return; } if (settings_provider::is_conflicting_permissions($context)) { return; } $cm = get_coursemodule_from_instance('quiz', $quiz->id, $quiz->course, false, MUST_EXIST); $settings = settings_provider::filter_plugin_settings($quiz); $settings->quizid = $quiz->id; $settings->cmid = $cm->id; // Get existing settings or create new settings if none exist.
< $quizsettings = quiz_settings::get_by_quiz_id($quiz->id);
> $quizsettings = seb_quiz_settings::get_by_quiz_id($quiz->id);
if (empty($quizsettings)) {
< $quizsettings = new quiz_settings(0, $settings);
> $quizsettings = new seb_quiz_settings(0, $settings);
} else { $settings->id = $quizsettings->get('id'); $quizsettings->from_record($settings); } // Process uploaded files if required. if ($quizsettings->get('requiresafeexambrowser') == settings_provider::USE_SEB_UPLOAD_CONFIG) { $draftitemid = file_get_submitted_draft_itemid('filemanager_sebconfigfile'); settings_provider::save_filemanager_sebconfigfile_draftarea($draftitemid, $cm->id); } else { settings_provider::delete_uploaded_config_file($cm->id); } // Save or delete settings. if ($quizsettings->get('requiresafeexambrowser') != settings_provider::USE_SEB_NO) { $quizsettings->save(); } else if ($quizsettings->get('id')) { $quizsettings->delete(); } } /** * Delete any rule-specific settings when the quiz is deleted. This is called * from {@link quiz_delete_instance()} in lib.php. *
< * @param object $quiz the data from the database, including $quiz->id
> * @param stdClass $quiz the data from the database, including $quiz->id
* which is the id of the quiz being deleted. */ public static function delete_settings($quiz) {
< $quizsettings = quiz_settings::get_by_quiz_id($quiz->id);
> $quizsettings = seb_quiz_settings::get_by_quiz_id($quiz->id);
// Check that there are existing settings. if ($quizsettings !== false) { $quizsettings->delete(); } } /** * Return the bits of SQL needed to load all the settings from all the access * plugins in one DB query. The easiest way to understand what you need to do
< * here is probalby to read the code of {@link quiz_access_manager::load_settings()}.
> * here is probably to read the code of {@see \mod_quiz\access_manager::load_settings()}.
* * If you have some settings that cannot be loaded in this way, then you can * use the {@link get_extra_settings()} method instead, but that has * performance implications. * * @param int $quizid the id of the quiz we are loading settings for. This * can also be accessed as quiz.id in the SQL. (quiz is a table alisas for {quiz}.) * @return array with three elements: * 1. fields: any fields to add to the select list. These should be alised * if neccessary so that the field name starts the name of the plugin. * 2. joins: any joins (should probably be LEFT JOINS) with other tables that * are needed. * 3. params: array of placeholder values that are needed by the SQL. You must * used named placeholders, and the placeholder names should start with the * plugin name, to avoid collisions. */ public static function get_settings_sql($quizid) : array { return [ 'seb.requiresafeexambrowser AS seb_requiresafeexambrowser, ' . 'seb.showsebtaskbar AS seb_showsebtaskbar, ' . 'seb.showwificontrol AS seb_showwificontrol, ' . 'seb.showreloadbutton AS seb_showreloadbutton, ' . 'seb.showtime AS seb_showtime, ' . 'seb.showkeyboardlayout AS seb_showkeyboardlayout, ' . 'seb.allowuserquitseb AS seb_allowuserquitseb, ' . 'seb.quitpassword AS seb_quitpassword, ' . 'seb.linkquitseb AS seb_linkquitseb, ' . 'seb.userconfirmquit AS seb_userconfirmquit, ' . 'seb.enableaudiocontrol AS seb_enableaudiocontrol, ' . 'seb.muteonstartup AS seb_muteonstartup, ' . 'seb.allowspellchecking AS seb_allowspellchecking, ' . 'seb.allowreloadinexam AS seb_allowreloadinexam, ' . 'seb.activateurlfiltering AS seb_activateurlfiltering, ' . 'seb.filterembeddedcontent AS seb_filterembeddedcontent, ' . 'seb.expressionsallowed AS seb_expressionsallowed, ' . 'seb.regexallowed AS seb_regexallowed, ' . 'seb.expressionsblocked AS seb_expressionsblocked, ' . 'seb.regexblocked AS seb_regexblocked, ' . 'seb.allowedbrowserexamkeys AS seb_allowedbrowserexamkeys, ' . 'seb.showsebdownloadlink AS seb_showsebdownloadlink, ' . 'sebtemplate.id AS seb_templateid ' , 'LEFT JOIN {quizaccess_seb_quizsettings} seb ON seb.quizid = quiz.id ' . 'LEFT JOIN {quizaccess_seb_template} sebtemplate ON seb.templateid = sebtemplate.id ' , [] ]; } /** * Whether the user should be blocked from starting a new attempt or continuing * an attempt now. * * @return string false if access should be allowed, a message explaining the * reason if access should be prevented. */ public function prevent_access() { global $PAGE; if (!$this->accessmanager->seb_required()) { return false; } if ($this->accessmanager->can_bypass_seb()) { return false; } // If the rule is active, enforce a secure view whilst taking the quiz. $PAGE->set_pagelayout('secure'); $this->prevent_display_blocks();
< if ($this->accessmanager->should_validate_basic_header() && !$this->accessmanager->validate_basic_header()) {
> // Access has previously been validated for this session and quiz. > if ($this->accessmanager->validate_session_access()) { > return false; > } > > if (!$this->accessmanager->validate_basic_header()) {
access_prevented::create_strict($this->accessmanager, $this->get_reason_text('not_seb'))->trigger(); return $this->get_require_seb_error_message(); }
< if ($this->accessmanager->should_validate_config_key() && !$this->accessmanager->validate_config_key()) { < if ($this->should_redirect_to_seb_config_link()) { < $this->redirect_to_seb_config_link();
> if (!$this->accessmanager->validate_config_key()) { > if ($this->accessmanager->should_redirect_to_seb_config_link()) { > $this->accessmanager->redirect_to_seb_config_link();
} access_prevented::create_strict($this->accessmanager, $this->get_reason_text('invalid_config_key'))->trigger(); return $this->get_invalid_key_error_message(); }
< if ($this->accessmanager->should_validate_browser_exam_key() && !$this->accessmanager->validate_browser_exam_keys()) {
> if (!$this->accessmanager->validate_browser_exam_key()) {
access_prevented::create_strict($this->accessmanager, $this->get_reason_text('invalid_browser_key'))->trigger(); return $this->get_invalid_key_error_message(); }
> // Set the state of the access for this Moodle session. return false; > $this->accessmanager->set_session_access(true); } >
/** * Returns a list of finished attempts for the current user. * * @return array */ private function get_user_finished_attempts() : array { global $USER; return quiz_get_user_attempts( $this->quizobj->get_quizid(), $USER->id, quiz_attempt::FINISHED, false ); } /** * Prevent block displaying as configured. */ private function prevent_display_blocks() { global $PAGE; if ($PAGE->has_set_url() && $PAGE->url == $this->quizobj->view_url()) { $attempts = $this->get_user_finished_attempts(); // Don't display blocks before starting an attempt. if (empty($attempts) && !get_config('quizaccess_seb', 'displayblocksbeforestart')) { $PAGE->blocks->show_only_fake_blocks(); } // Don't display blocks after finishing an attempt. if (!empty($attempts) && !get_config('quizaccess_seb', 'displayblockswhenfinished')) { $PAGE->blocks->show_only_fake_blocks(); } } } /** * Returns reason for access prevention as a text. * * @param string $identifier Reason string identifier. * @return string */ private function get_reason_text(string $identifier) : string { if (in_array($identifier, ['not_seb', 'invalid_config_key', 'invalid_browser_key'])) { return get_string($identifier, 'quizaccess_seb'); } return get_string('unknown_reason', 'quizaccess_seb'); } /** * Return error message when a SEB key is not valid. * * @return string */ private function get_invalid_key_error_message() : string { // Return error message with download link and links to get the seb config. return get_string('invalidkeys', 'quizaccess_seb') . $this->display_buttons($this->get_action_buttons()); } /** * Return error message when a SEB browser is not used. * * @return string */ private function get_require_seb_error_message() : string { $message = get_string('clientrequiresseb', 'quizaccess_seb'); if ($this->should_display_download_seb_link()) { $message .= $this->display_buttons($this->get_download_seb_button()); } // Return error message with download link. return $message; } /** * Helper function to display an Exit Safe Exam Browser button if configured to do so and attempts are > 0. * * @return string empty or a button which has the configured seb quit link. */ private function get_quit_button() : string { $quitbutton = ''; if (empty($this->get_user_finished_attempts())) { return $quitbutton; } // Only display if the link has been configured and attempts are greater than 0. if (!empty($this->quiz->seb_linkquitseb)) { $quitbutton = html_writer::link( $this->quiz->seb_linkquitseb, get_string('exitsebbutton', 'quizaccess_seb'), ['class' => 'btn btn-secondary'] ); } return $quitbutton; } /** * Information, such as might be shown on the quiz view page, relating to this restriction. * There is no obligation to return anything. If it is not appropriate to tell students * about this rule, then just return ''. * * @return mixed a message, or array of messages, explaining the restriction * (may be '' if no message is appropriate). */ public function description() : array {
> global $PAGE; $messages = [get_string('sebrequired', 'quizaccess_seb')]; >
// Display download SEB config link for those who can bypass using SEB. if ($this->accessmanager->can_bypass_seb() && $this->accessmanager->should_validate_config_key()) { $messages[] = $this->display_buttons($this->get_download_config_button()); } // Those with higher level access will be able to see the button if they've made an attempt. if (!$this->prevent_access()) { $messages[] = $this->display_buttons($this->get_quit_button());
> } else { } > $PAGE->requires->js_call_amd('quizaccess_seb/validate_quiz_access', 'init', > [$this->quiz->cmid, (bool)get_config('quizaccess_seb', 'autoreconfigureseb')]);
return $messages; } /** * Sets up the attempt (review or summary) page with any special extra * properties required by this rule. * * @param moodle_page $page the page object to initialise. */ public function setup_attempt_page($page) { $page->set_title($this->quizobj->get_course()->shortname . ': ' . $page->title); $page->set_popup_notification_allowed(false); // Prevent message notifications. $page->set_heading($page->title); $page->set_pagelayout('secure'); } /**
> * This is called when the current attempt at the quiz is finished. * Prepare buttons HTML code for being displayed on the screen. > */ * > public function current_attempt_finished() { * @param string $buttonshtml Html string of the buttons. > $this->accessmanager->clear_session_access(); * @param string $class Optional CSS class (or classes as space-separated list) > } * @param array $attributes Optional other attributes as array > * > /**
* @return string HTML code of the provided buttons. */ private function display_buttons(string $buttonshtml, $class = '', array $attributes = null) : string { $html = ''; if (!empty($buttonshtml)) { $html = html_writer::div($buttonshtml, $class, $attributes); } return $html; } /** * Get buttons to prompt user to download SEB or config file or launch SEB. * * @return string Html block of all action buttons. */ private function get_action_buttons() : string { $buttons = ''; if ($this->should_display_download_seb_link()) { $buttons .= $this->get_download_seb_button(); } // Get config for displaying links. $linkconfig = explode(',', get_config('quizaccess_seb', 'showseblinks')); // Display links to download config/launch SEB only if required. if ($this->accessmanager->should_validate_config_key()) { if (in_array('seb', $linkconfig)) { $buttons .= $this->get_launch_seb_button(); } if (in_array('http', $linkconfig)) { $buttons .= $this->get_download_config_button(); } } return $buttons; } /** * Get a button to download SEB. * * @return string A link to download SafeExam Browser. */ private function get_download_seb_button() : string { global $OUTPUT; $button = ''; if (!empty($this->get_seb_download_url())) { $button = $OUTPUT->single_button($this->get_seb_download_url(), get_string('sebdownloadbutton', 'quizaccess_seb')); } return $button; } /** * Get a button to launch Safe Exam Browser. * * @return string A link to launch Safe Exam Browser. */ private function get_launch_seb_button() : string { // Rendering as a href and not as button in a form to circumvent browser warnings for sending to URL with unknown protocol. $seblink = \quizaccess_seb\link_generator::get_link($this->quiz->cmid, true, is_https());
< $buttonlink = html_writer::start_tag('div', array('class' => 'singlebutton'));
> $buttonlink = html_writer::start_tag('div', ['class' => 'singlebutton']);
$buttonlink .= html_writer::link($seblink, get_string('seblinkbutton', 'quizaccess_seb'), ['class' => 'btn btn-secondary', 'title' => get_string('seblinkbutton', 'quizaccess_seb')]); $buttonlink .= html_writer::end_tag('div'); return $buttonlink; } /** * Get a button to download Safe Exam Browser config. * * @return string A link to launch Safe Exam Browser. */ private function get_download_config_button() : string { // Rendering as a href and not as button in a form to circumvent browser warnings for sending to URL with unknown protocol. $httplink = \quizaccess_seb\link_generator::get_link($this->quiz->cmid, false, is_https());
< $buttonlink = html_writer::start_tag('div', array('class' => 'singlebutton'));
> $buttonlink = html_writer::start_tag('div', ['class' => 'singlebutton']);
$buttonlink .= html_writer::link($httplink, get_string('httplinkbutton', 'quizaccess_seb'), ['class' => 'btn btn-secondary', 'title' => get_string('httplinkbutton', 'quizaccess_seb')]); $buttonlink .= html_writer::end_tag('div'); return $buttonlink; } /** * Returns SEB download URL. * * @return string */ private function get_seb_download_url() : string { return get_config('quizaccess_seb', 'downloadlink'); } /** * Check if we should display a link to download Safe Exam Browser. * * @return bool */ private function should_display_download_seb_link() : bool { return !empty($this->quiz->seb_showsebdownloadlink); }
< < /** < * Redirect to SEB config link. This will force Safe Exam Browser to be reconfigured. < */ < private function redirect_to_seb_config_link() { < global $PAGE; < < $seblink = \quizaccess_seb\link_generator::get_link($this->quiz->cmid, true, is_https()); < $PAGE->requires->js_amd_inline("document.location.replace('" . $seblink . "')"); < } < < /** < * Check if we need to redirect to SEB config link. < * @return bool < */ < private function should_redirect_to_seb_config_link() : bool { < return $this->accessmanager->is_using_seb() && get_config('quizaccess_seb', 'autoreconfigureseb'); < } <
}