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Long Term Support Release
<?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 auth_lti\local\ltiadvantage\entity\user_migration_claim; defined('MOODLE_INTERNAL') || die(); require_once($CFG->libdir.'/authlib.php'); require_once($CFG->libdir.'/accesslib.php'); /** * LTI Authentication plugin. * * @package auth_lti * @copyright 2016 Mark Nelson <markn@moodle.com> * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class auth_plugin_lti extends \auth_plugin_base { /** * @var int constant representing the automatic account provisioning mode. * On first launch, for a previously unbound user, this mode dictates that a new Moodle account will be created automatically * for the user and bound to their platform credentials {iss, sub}. */ public const PROVISIONING_MODE_AUTO_ONLY = 1; /** * @var int constant representing the prompt for new or existing provisioning mode. * On first launch, for a previously unbound user, the mode dictates that the launch user will be presented with an options * view, allowing them to select either 'link an existing account' or 'create a new account for me'. */ public const PROVISIONING_MODE_PROMPT_NEW_EXISTING = 2; /** * @var int constant representing the prompt for existing only provisioning mode. * On first launch, for a previously unbound user, the mode dictates that the launch user will be presented with a view allowing * them to link an existing account only. This is useful for situations like deep linking, where an existing account is needed. */ public const PROVISIONING_MODE_PROMPT_EXISTING_ONLY = 3; /** * Constructor. */ public function __construct() { $this->authtype = 'lti'; } /** * Users can not log in via the traditional login form. * * @param string $username The username * @param string $password The password * @return bool Authentication success or failure */ public function user_login($username, $password) { return false; } /** * Authenticate the user based on the unique {iss, sub} tuple present in the OIDC JWT. * * This method ensures a Moodle user account has been found or is created, that the user is linked to the relevant * LTI Advantage credentials (iss, sub) and that the user account is logged in. * * Launch code can therefore rely on this method to get a session before doing things like calling require_login(). * * This method supports two workflows: * 1. Automatic account provisioning - where the complete_login() call will ALWAYS create/find a user and return to * calling code directly. No user interaction is required. * * 2. Manual account provisioning - where the complete_login() call will redirect ONLY ONCE to a login page, * where the user can decide whether to use an automatically provisioned account, or bind an existing user account. * When the decision has been made, the relevant account is bound and the user is redirected back to $returnurl. * Once an account has been bound via this selection process, subsequent calls to complete_login() will return to * calling code directly. Any calling code must provide its $returnurl to support the return from the account * selection process and must also take care to cache any JWT data appropriately, since the return will not inlude * that information. * * Which workflow is chosen depends on the roles present in the JWT. * For teachers/admins, manual provisioning will take place. These user type are likely to have existing accounts. * For learners, automatic provisioning will take place. * * Migration of legacy users is supported, however, only for the Learner role (automatic provisioning). Admins and * teachers are likely to have existing accounts and we want them to be able to select and bind these, rather than * binding an automatically provisioned legacy account which doesn't represent their real user account. * * The JWT data must be verified elsewhere. The code here assumes its integrity/authenticity. * * @param array $launchdata the JWT data provided in the link launch. * @param moodle_url $returnurl the local URL to return to if authentication workflows are required. * @param int $provisioningmode the desired account provisioning mode, which controls the auth flow for unbound users. * @param array $legacyconsumersecrets an array of secrets used by the legacy consumer if a migration claim exists. * @throws coding_exception if the specified provisioning mode is invalid. */ public function complete_login(array $launchdata, moodle_url $returnurl, int $provisioningmode, array $legacyconsumersecrets = []): void { // The platform user is already linked with a user account. if ($this->get_user_binding($launchdata['iss'], $launchdata['sub'])) { // Always sync the PII, regardless of whether we're already authenticated as this user or not. $user = $this->find_or_create_user_from_launch($launchdata, true); if (isloggedin()) { // If a different user is currently logged in, authenticate the linked user instead. global $USER; if ((int) $USER->id !== $user->id) { complete_user_login($user); } // If the linked user is already logged in, skip the call to complete_user_login() because this affects deep linking // workflows on sites publishing and consuming resources on the same site, due to the regenerated sesskey. return; } else { complete_user_login($user); return; } } // The platform user is not bound to a user account, check provisioning mode now. if (!$this->is_valid_provisioning_mode($provisioningmode)) { throw new coding_exception('Invalid account provisioning mode provided to complete_login().'); } switch ($provisioningmode) { case self::PROVISIONING_MODE_AUTO_ONLY: // Automatic provisioning - this will create/migrate a user account and log the user in. complete_user_login($this->find_or_create_user_from_launch($launchdata, true, $legacyconsumersecrets)); break; case self::PROVISIONING_MODE_PROMPT_NEW_EXISTING: case self::PROVISIONING_MODE_PROMPT_EXISTING_ONLY: default: // Allow linking an existing account or creation of a new account via an intermediate account options page. // Cache the relevant data and take the user to the account options page. // Note: This mode also depends on the global auth config 'authpreventaccountcreation'. If set, only existing // accounts can be bound in this provisioning mode. global $SESSION; $SESSION->auth_lti = (object)[ 'launchdata' => $launchdata, 'returnurl' => $returnurl, 'provisioningmode' => $provisioningmode ]; redirect(new moodle_url('/auth/lti/login.php', [ 'sesskey' => sesskey(), ])); break; } } /** * Get a Moodle user account for the LTI user based on the user details returned by a NRPS 2 membership call. * * This method expects a single member structure, in array format, as defined here: * See: https://www.imsglobal.org/spec/lti-nrps/v2p0#membership-container-media-type. * * This method supports migration of user accounts used in legacy launches, provided the legacy consumerkey corresponding to * to the legacy consumer is provided. Calling code will have verified the migration claim during initial launches and should * have the consumer key mapped to the deployment, ready to pass in. * * @param array $member the member data, in array format. * @param string $iss the issuer to which the member relates. * @param string $legacyconsumerkey optional consumer key mapped to the deployment to facilitate user migration. * @return stdClass a Moodle user record. */ public function find_or_create_user_from_membership(array $member, string $iss, string $legacyconsumerkey = ''): stdClass { // Picture is not synced with membership-based auths because sync tasks may wish to perform slow operations like this a // different way. unset($member['picture']); if ($binduser = $this->get_user_binding($iss, $member['user_id'])) {< $user = \core_user::get_user((int) $binduser);> $user = \core_user::get_user($binduser);$this->update_user_account($user, $member, $iss); return \core_user::get_user($user->id); } else { if (!empty($legacyconsumerkey)) { // Consumer key is required to attempt user migration because legacy users were identified by a // username consisting of the consumer key and user id. // See the legacy \enrol_lti\helper::create_username() for details. $legacyuserid = $member['lti11_legacy_user_id'] ?? $member['user_id']; $username = 'enrol_lti' . sha1($legacyconsumerkey . '::' . $legacyconsumerkey . ':' . $legacyuserid); if ($user = \core_user::get_user_by_username($username)) { $this->create_user_binding($iss, $member['user_id'], $user->id); $this->update_user_account($user, $member, $iss); return \core_user::get_user($user->id); } } $user = $this->create_new_account($member, $iss); return \core_user::get_user($user->id); } } /** * Get a Moodle user account for the LTI user corresponding to the user defined in a link launch. * * This method supports migration of user accounts used in legacy launches, provided the legacy consumer secrets corresponding * to the legacy consumer are provided. If calling code wishes migration to be role-specific, it should check roles accordingly * itself and pass relevant data in - as auth_plugin_lti::complete_login() does. * * @param array $launchdata all data in the decoded JWT including iss and sub. * @param bool $syncpicture whether to sync the user's picture with the picture sent in the launch. * @param array $legacyconsumersecrets all secrets found for the legacy consumer, facilitating user migration. * @return stdClass the Moodle user who is mapped to the platform user identified in the JWT data. */ public function find_or_create_user_from_launch(array $launchdata, bool $syncpicture = false, array $legacyconsumersecrets = []): stdClass { if (!$syncpicture) { unset($launchdata['picture']); } if ($binduser = $this->get_user_binding($launchdata['iss'], $launchdata['sub'])) {< $user = \core_user::get_user((int) $binduser);> $user = \core_user::get_user($binduser);$this->update_user_account($user, $launchdata, $launchdata['iss']); return \core_user::get_user($user->id); } else { // Is the intent to migrate a user account used in legacy launches? if (!empty($legacyconsumersecrets)) { try { // Validate the migration claim and try to find a legacy user. $usermigrationclaim = new user_migration_claim($launchdata, $legacyconsumersecrets); $username = 'enrol_lti' . sha1($usermigrationclaim->get_consumer_key() . '::' . $usermigrationclaim->get_consumer_key() .':' .$usermigrationclaim->get_user_id()); if ($user = \core_user::get_user_by_username($username)) { $this->create_user_binding($launchdata['iss'], $launchdata['sub'], $user->id); $this->update_user_account($user, $launchdata, $launchdata['iss']); return \core_user::get_user($user->id); } } catch (Exception $e) { // There was an issue validating the user migration claim. We don't want to fail auth entirely though. // Rather, we want to fall back to new account creation and log the attempt. debugging("There was a problem migrating the LTI user '{$launchdata['sub']}' on the platform " . "'{$launchdata['iss']}'. The migration claim could not be validated. A new account will be created."); } } $user = $this->create_new_account($launchdata, $launchdata['iss']); $this->update_user_account($user, $launchdata, $launchdata['iss']); return \core_user::get_user($user->id); } } /** * Create a binding between the LTI user, as identified by {iss, sub} tuple and the user id. * * @param string $iss the issuer URL identifying the platform to which to user belongs. * @param string $sub the sub string identifying the user on the platform. * @param int $userid the id of the Moodle user account to bind. */ public function create_user_binding(string $iss, string $sub, int $userid): void { global $DB; $timenow = time(); $issuer256 = hash('sha256', $iss); $sub256 = hash('sha256', $sub); if ($DB->record_exists('auth_lti_linked_login', ['issuer256' => $issuer256, 'sub256' => $sub256])) { return; } $rec = [ 'userid' => $userid, 'issuer' => $iss, 'issuer256' => $issuer256, 'sub' => $sub, 'sub256' => $sub256, 'timecreated' => $timenow, 'timemodified' => $timenow ]; $DB->insert_record('auth_lti_linked_login', $rec); } /** * Gets the id of the linked Moodle user account for an LTI user, or null if not found. * * @param string $issuer the issuer to which the user belongs. * @param string $sub the sub string identifying the user on the issuer. * @return int|null the id of the corresponding Moodle user record, or null if not found. */ public function get_user_binding(string $issuer, string $sub): ?int { global $DB; $issuer256 = hash('sha256', $issuer); $sub256 = hash('sha256', $sub); try { $binduser = $DB->get_field('auth_lti_linked_login', 'userid', ['issuer256' => $issuer256, 'sub256' => $sub256], MUST_EXIST); } catch (\dml_exception $e) { $binduser = null; } return $binduser; } /** * Check whether a provisioning mode is valid or not. * * @param int $mode the mode * @return bool true if valid for use, false otherwise. */ protected function is_valid_provisioning_mode(int $mode): bool { $validmodes = [ self::PROVISIONING_MODE_AUTO_ONLY, self::PROVISIONING_MODE_PROMPT_NEW_EXISTING, self::PROVISIONING_MODE_PROMPT_EXISTING_ONLY ]; return in_array($mode, $validmodes); } /** * Create a new user account based on the user data either in the launch JWT or from a membership call. * * @param array $userdata the user data coming from either a launch or membership service call. * @param string $iss the issuer to which the user belongs. * @return stdClass a complete Moodle user record. */ protected function create_new_account(array $userdata, string $iss): stdClass { global $CFG; require_once($CFG->dirroot.'/user/lib.php'); // Launches and membership calls handle the user id differently. // Launch uses 'sub', whereas member uses 'user_id'. $userid = !empty($userdata['sub']) ? $userdata['sub'] : $userdata['user_id']; $user = new stdClass(); $user->username = 'enrol_lti_13_' . sha1($iss . '_' . $userid); // If the email was stripped/not set then fill it with a default one. // This stops the user from being redirected to edit their profile page. $email = !empty($userdata['email']) ? $userdata['email'] : 'enrol_lti_13_' . sha1($iss . '_' . $userid) . "@example.com"; $email = \core_user::clean_field($email, 'email'); $user->email = $email; $user->auth = 'lti'; $user->mnethostid = $CFG->mnet_localhost_id; $user->firstname = $userdata['given_name'] ?? $userid; $user->lastname = $userdata['family_name'] ?? $iss; $user->password = ''; $user->confirmed = 1; $user->id = user_create_user($user, false); // Link this user with the LTI credentials for future use. $this->create_user_binding($iss, $userid, $user->id); return (object) get_complete_user_data('id', $user->id); } /** * Update the personal fields of the user account, based on data present in either a launch of member sync call. * * @param stdClass $user the Moodle user account to update. * @param array $userdata the user data coming from either a launch or membership service call. * @param string $iss the issuer to which the user belongs. */ protected function update_user_account(stdClass $user, array $userdata, string $iss): void { global $CFG; require_once($CFG->dirroot.'/user/lib.php'); if ($user->auth !== 'lti') { return; } // Launches and membership calls handle the user id differently. // Launch uses 'sub', whereas member uses 'user_id'. $platformuserid = !empty($userdata['sub']) ? $userdata['sub'] : $userdata['user_id']; $email = !empty($userdata['email']) ? $userdata['email'] : 'enrol_lti_13_' . sha1($iss . '_' . $platformuserid) . "@example.com"; $email = \core_user::clean_field($email, 'email'); $update = [ 'id' => $user->id, 'firstname' => $userdata['given_name'] ?? $platformuserid, 'lastname' => $userdata['family_name'] ?? $iss, 'email' => $email ]; $userfieldstocompare = array_intersect_key((array) $user, $update); if (!empty(array_diff($update, $userfieldstocompare))) { user_update_user($update); // Only update if there's a change. } if (!empty($userdata['picture'])) { try { $this->update_user_picture($user->id, $userdata['picture']); } catch (Exception $e) { debugging("Error syncing the profile picture for user '$user->id' during LTI authentication."); } } } /** * Update the user's picture with the image stored at $url. * * @param int $userid the id of the user to update. * @param string $url the string URL where the new image can be found. * @throws moodle_exception if there were any problems updating the picture. */ protected function update_user_picture(int $userid, string $url): void { global $CFG, $DB; require_once($CFG->libdir . '/filelib.php'); require_once($CFG->libdir . '/gdlib.php'); $fs = get_file_storage(); $context = \context_user::instance($userid, MUST_EXIST); $fs->delete_area_files($context->id, 'user', 'newicon'); $filerecord = array( 'contextid' => $context->id, 'component' => 'user', 'filearea' => 'newicon', 'itemid' => 0, 'filepath' => '/' ); $urlparams = array( 'calctimeout' => false, 'timeout' => 5, 'skipcertverify' => true, 'connecttimeout' => 5 ); try { $fs->create_file_from_url($filerecord, $url, $urlparams); } catch (\file_exception $e) { throw new moodle_exception(get_string($e->errorcode, $e->module, $e->a)); } $iconfile = $fs->get_area_files($context->id, 'user', 'newicon', false, 'itemid', false); // There should only be one. $iconfile = reset($iconfile); // Something went wrong while creating temp file - remove the uploaded file. if (!$iconfile = $iconfile->copy_content_to_temp()) { $fs->delete_area_files($context->id, 'user', 'newicon'); throw new moodle_exception('There was a problem copying the profile picture to temp.'); } // Copy file to temporary location and the send it for processing icon. $newpicture = (int) process_new_icon($context, 'user', 'icon', 0, $iconfile); // Delete temporary file. @unlink($iconfile); // Remove uploaded file. $fs->delete_area_files($context->id, 'user', 'newicon'); // Set the user's picture. $DB->set_field('user', 'picture', $newpicture, array('id' => $userid)); } }