/auth/ldap/auth.php

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<?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/>.

/**
 * Authentication Plugin: LDAP Authentication
 * Authentication using LDAP (Lightweight Directory Access Protocol).
 *
 * @package auth_ldap
 * @author Martin Dougiamas
 * @author Iñaki Arenaza
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 */

defined('MOODLE_INTERNAL') || die();

// See http://support.microsoft.com/kb/305144 to interprete these values.
if (!defined('AUTH_AD_ACCOUNTDISABLE')) {
    define('AUTH_AD_ACCOUNTDISABLE', 0x0002);
}
if (!defined('AUTH_AD_NORMAL_ACCOUNT')) {
    define('AUTH_AD_NORMAL_ACCOUNT', 0x0200);
}
if (!defined('AUTH_NTLMTIMEOUT')) {  // timewindow for the NTLM SSO process, in secs...
    define('AUTH_NTLMTIMEOUT', 10);
}

// UF_DONT_EXPIRE_PASSWD value taken from MSDN directly
if (!defined('UF_DONT_EXPIRE_PASSWD')) {
    define ('UF_DONT_EXPIRE_PASSWD', 0x00010000);
}

// The Posix uid and gid of the 'nobody' account and 'nogroup' group.
if (!defined('AUTH_UID_NOBODY')) {
    define('AUTH_UID_NOBODY', -2);
}
if (!defined('AUTH_GID_NOGROUP')) {
    define('AUTH_GID_NOGROUP', -2);
}

// Regular expressions for a valid NTLM username and domain name.
if (!defined('AUTH_NTLM_VALID_USERNAME')) {
    define('AUTH_NTLM_VALID_USERNAME', '[^/\\\\\\\\\[\]:;|=,+*?<>@"]+');
}
if (!defined('AUTH_NTLM_VALID_DOMAINNAME')) {
    define('AUTH_NTLM_VALID_DOMAINNAME', '[^\\\\\\\\\/:*?"<>|]+');
}
// Default format for remote users if using NTLM SSO
if (!defined('AUTH_NTLM_DEFAULT_FORMAT')) {
    define('AUTH_NTLM_DEFAULT_FORMAT', '%domain%\\%username%');
}
if (!defined('AUTH_NTLM_FASTPATH_ATTEMPT')) {
    define('AUTH_NTLM_FASTPATH_ATTEMPT', 0);
}
if (!defined('AUTH_NTLM_FASTPATH_YESFORM')) {
    define('AUTH_NTLM_FASTPATH_YESFORM', 1);
}
if (!defined('AUTH_NTLM_FASTPATH_YESATTEMPT')) {
    define('AUTH_NTLM_FASTPATH_YESATTEMPT', 2);
}

// Allows us to retrieve a diagnostic message in case of LDAP operation error
if (!defined('LDAP_OPT_DIAGNOSTIC_MESSAGE')) {
    define('LDAP_OPT_DIAGNOSTIC_MESSAGE', 0x0032);
}

require_once($CFG->libdir.'/authlib.php');
require_once($CFG->libdir.'/ldaplib.php');
require_once($CFG->dirroot.'/user/lib.php');
require_once($CFG->dirroot.'/auth/ldap/locallib.php');

/**
 * LDAP authentication plugin.
 */
class auth_plugin_ldap extends auth_plugin_base {

    /**
     * Init plugin config from database settings depending on the plugin auth type.
     */
    function init_plugin($authtype) {
        $this->pluginconfig = 'auth_'.$authtype;
        $this->config = get_config($this->pluginconfig);
        if (empty($this->config->ldapencoding)) {
            $this->config->ldapencoding = 'utf-8';
        }
        if (empty($this->config->user_type)) {
            $this->config->user_type = 'default';
        }

        $ldap_usertypes = ldap_supported_usertypes();
        $this->config->user_type_name = $ldap_usertypes[$this->config->user_type];
        unset($ldap_usertypes);

        $default = ldap_getdefaults();

        // Use defaults if values not given
        foreach ($default as $key => $value) {
            // watch out - 0, false are correct values too
            if (!isset($this->config->{$key}) or $this->config->{$key} == '') {
                $this->config->{$key} = $value[$this->config->user_type];
            }
        }

        // Hack prefix to objectclass
        $this->config->objectclass = ldap_normalise_objectclass($this->config->objectclass);
    }

    /**
     * Constructor with initialisation.
     */
    public function __construct() {
        $this->authtype = 'ldap';
        $this->roleauth = 'auth_ldap';
        $this->errorlogtag = '[AUTH LDAP] ';
        $this->init_plugin($this->authtype);
    }

    /**
     * Old syntax of class constructor. Deprecated in PHP7.
     *
     * @deprecated since Moodle 3.1
     */
    public function auth_plugin_ldap() {
        debugging('Use of class name as constructor is deprecated', DEBUG_DEVELOPER);
        self::__construct();
    }

    /**
     * Returns true if the username and password work and false if they are
     * wrong or don't exist.
     *
     * @param string $username The username (without system magic quotes)
     * @param string $password The password (without system magic quotes)
     *
     * @return bool Authentication success or failure.
     */
    function user_login($username, $password) {
        if (! function_exists('ldap_bind')) {
            print_error('auth_ldapnotinstalled', 'auth_ldap');
            return false;
        }

        if (!$username or !$password) {    // Don't allow blank usernames or passwords
            return false;
        }

        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);
        $extpassword = core_text::convert($password, 'utf-8', $this->config->ldapencoding);

        // Before we connect to LDAP, check if this is an AD SSO login
        // if we succeed in this block, we'll return success early.
        //
        $key = sesskey();
        if (!empty($this->config->ntlmsso_enabled) && $key === $password) {
            $sessusername = get_cache_flag($this->pluginconfig.'/ntlmsess', $key);
            // We only get the cache flag if we retrieve it before
            // it expires (AUTH_NTLMTIMEOUT seconds).
            if (empty($sessusername)) {
                return false;
            }

            if ($username === $sessusername) {
                unset($sessusername);

                // Check that the user is inside one of the configured LDAP contexts
                $validuser = false;
                $ldapconnection = $this->ldap_connect();
                // if the user is not inside the configured contexts,
                // ldap_find_userdn returns false.
                if ($this->ldap_find_userdn($ldapconnection, $extusername)) {
                    $validuser = true;
                }
                $this->ldap_close();

                // Shortcut here - SSO confirmed
                return $validuser;
            }
        } // End SSO processing
        unset($key);

        $ldapconnection = $this->ldap_connect();
        $ldap_user_dn = $this->ldap_find_userdn($ldapconnection, $extusername);

        // If ldap_user_dn is empty, user does not exist
        if (!$ldap_user_dn) {
            $this->ldap_close();
            return false;
        }

        // Try to bind with current username and password
        $ldap_login = @ldap_bind($ldapconnection, $ldap_user_dn, $extpassword);

        // If login fails and we are using MS Active Directory, retrieve the diagnostic
        // message to see if this is due to an expired password, or that the user is forced to
        // change the password on first login. If it is, only proceed if we can change
        // password from Moodle (otherwise we'll get stuck later in the login process).
        if (!$ldap_login && ($this->config->user_type == 'ad')
            && $this->can_change_password()
            && (!empty($this->config->expiration) and ($this->config->expiration == 1))) {

            // We need to get the diagnostic message right after the call to ldap_bind(),
            // before any other LDAP operation.
            ldap_get_option($ldapconnection, LDAP_OPT_DIAGNOSTIC_MESSAGE, $diagmsg);

            if ($this->ldap_ad_pwdexpired_from_diagmsg($diagmsg)) {
                // If login failed because user must change the password now or the
                // password has expired, let the user in. We'll catch this later in the
                // login process when we explicitly check for expired passwords.
                $ldap_login = true;
            }
        }
        $this->ldap_close();
        return $ldap_login;
    }

    /**
     * Reads user information from ldap and returns it in array()
     *
     * Function should return all information available. If you are saving
     * this information to moodle user-table you should honor syncronization flags
     *
     * @param string $username username
     *
     * @return mixed array with no magic quotes or false on error
     */
    function get_userinfo($username) {
        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();
        if(!($user_dn = $this->ldap_find_userdn($ldapconnection, $extusername))) {
            $this->ldap_close();
            return false;
        }

        $search_attribs = array();
        $attrmap = $this->ldap_attributes();
        foreach ($attrmap as $key => $values) {
            if (!is_array($values)) {
                $values = array($values);
            }
            foreach ($values as $value) {
                if (!in_array($value, $search_attribs)) {
                    array_push($search_attribs, $value);
                }
            }
        }

        if (!$user_info_result = ldap_read($ldapconnection, $user_dn, '(objectClass=*)', $search_attribs)) {
            $this->ldap_close();
            return false; // error!
        }

        $user_entry = ldap_get_entries_moodle($ldapconnection, $user_info_result);
        if (empty($user_entry)) {
            $this->ldap_close();
            return false; // entry not found
        }

        $result = array();
        foreach ($attrmap as $key => $values) {
            if (!is_array($values)) {
                $values = array($values);
            }
            $ldapval = NULL;
            foreach ($values as $value) {
                $entry = $user_entry[0];
                if (($value == 'dn') || ($value == 'distinguishedname')) {
                    $result[$key] = $user_dn;
                    continue;
                }
                if (!array_key_exists($value, $entry)) {
                    continue; // wrong data mapping!
                }
                if (is_array($entry[$value])) {
                    $newval = core_text::convert($entry[$value][0], $this->config->ldapencoding, 'utf-8');
                } else {
                    $newval = core_text::convert($entry[$value], $this->config->ldapencoding, 'utf-8');
                }
                if (!empty($newval)) { // favour ldap entries that are set
                    $ldapval = $newval;
                }
            }
            if (!is_null($ldapval)) {
                $result[$key] = $ldapval;
            }
        }

        $this->ldap_close();
        return $result;
    }

    /**
     * Reads user information from ldap and returns it in an object
     *
     * @param string $username username (with system magic quotes)
     * @return mixed object or false on error
     */
    function get_userinfo_asobj($username) {
        $user_array = $this->get_userinfo($username);
        if ($user_array == false) {
            return false; //error or not found
        }
        $user_array = truncate_userinfo($user_array);
        $user = new stdClass();
        foreach ($user_array as $key=>$value) {
            $user->{$key} = $value;
        }
        return $user;
    }

    /**
     * Returns all usernames from LDAP
     *
     * get_userlist returns all usernames from LDAP
     *
     * @return array
     */
    function get_userlist() {
        return $this->ldap_get_userlist("({$this->config->user_attribute}=*)");
    }

    /**
     * Checks if user exists on LDAP
     *
     * @param string $username
     */
    function user_exists($username) {
        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        // Returns true if given username exists on ldap
        $users = $this->ldap_get_userlist('('.$this->config->user_attribute.'='.ldap_filter_addslashes($extusername).')');
        return count($users);
    }

    /**
     * Creates a new user on LDAP.
     * By using information in userobject
     * Use user_exists to prevent duplicate usernames
     *
     * @param mixed $userobject  Moodle userobject
     * @param mixed $plainpass   Plaintext password
     */
    function user_create($userobject, $plainpass) {
        $extusername = core_text::convert($userobject->username, 'utf-8', $this->config->ldapencoding);
        $extpassword = core_text::convert($plainpass, 'utf-8', $this->config->ldapencoding);

        switch ($this->config->passtype) {
            case 'md5':
                $extpassword = '{MD5}' . base64_encode(pack('H*', md5($extpassword)));
                break;
            case 'sha1':
                $extpassword = '{SHA}' . base64_encode(pack('H*', sha1($extpassword)));
                break;
            case 'plaintext':
            default:
                break; // plaintext
        }

        $ldapconnection = $this->ldap_connect();
        $attrmap = $this->ldap_attributes();

        $newuser = array();

        foreach ($attrmap as $key => $values) {
            if (!is_array($values)) {
                $values = array($values);
            }
            foreach ($values as $value) {
                if (!empty($userobject->$key) ) {
                    $newuser[$value] = core_text::convert($userobject->$key, 'utf-8', $this->config->ldapencoding);
                }
            }
        }

        //Following sets all mandatory and other forced attribute values
        //User should be creted as login disabled untill email confirmation is processed
        //Feel free to add your user type and send patches to paca@sci.fi to add them
        //Moodle distribution

        switch ($this->config->user_type)  {
            case 'edir':
                $newuser['objectClass']   = array('inetOrgPerson', 'organizationalPerson', 'person', 'top');
                $newuser['uniqueId']      = $extusername;
                $newuser['logindisabled'] = 'TRUE';
                $newuser['userpassword']  = $extpassword;
                $uadd = ldap_add($ldapconnection, $this->config->user_attribute.'='.ldap_addslashes($extusername).','.$this->config->create_context, $newuser);
                break;
            case 'rfc2307':
            case 'rfc2307bis':
                // posixAccount object class forces us to specify a uidNumber
                // and a gidNumber. That is quite complicated to generate from
                // Moodle without colliding with existing numbers and without
                // race conditions. As this user is supposed to be only used
                // with Moodle (otherwise the user would exist beforehand) and
                // doesn't need to login into a operating system, we assign the
                // user the uid of user 'nobody' and gid of group 'nogroup'. In
                // addition to that, we need to specify a home directory. We
                // use the root directory ('/') as the home directory, as this
                // is the only one can always be sure exists. Finally, even if
                // it's not mandatory, we specify '/bin/false' as the login
                // shell, to prevent the user from login in at the operating
                // system level (Moodle ignores this).

                $newuser['objectClass']   = array('posixAccount', 'inetOrgPerson', 'organizationalPerson', 'person', 'top');
                $newuser['cn']            = $extusername;
                $newuser['uid']           = $extusername;
                $newuser['uidNumber']     = AUTH_UID_NOBODY;
                $newuser['gidNumber']     = AUTH_GID_NOGROUP;
                $newuser['homeDirectory'] = '/';
                $newuser['loginShell']    = '/bin/false';

                // IMPORTANT:
                // We have to create the account locked, but posixAccount has
                // no attribute to achive this reliably. So we are going to
                // modify the password in a reversable way that we can later
                // revert in user_activate().
                //
                // Beware that this can be defeated by the user if we are not
                // using MD5 or SHA-1 passwords. After all, the source code of
                // Moodle is available, and the user can see the kind of
                // modification we are doing and 'undo' it by hand (but only
                // if we are using plain text passwords).
                //
                // Also bear in mind that you need to use a binding user that
                // can create accounts and has read/write privileges on the
                // 'userPassword' attribute for this to work.

                $newuser['userPassword']  = '*'.$extpassword;
                $uadd = ldap_add($ldapconnection, $this->config->user_attribute.'='.ldap_addslashes($extusername).','.$this->config->create_context, $newuser);
                break;
            case 'ad':
                // User account creation is a two step process with AD. First you
                // create the user object, then you set the password. If you try
                // to set the password while creating the user, the operation
                // fails.

                // Passwords in Active Directory must be encoded as Unicode
                // strings (UCS-2 Little Endian format) and surrounded with
                // double quotes. See http://support.microsoft.com/?kbid=269190
                if (!function_exists('mb_convert_encoding')) {
                    print_error('auth_ldap_no_mbstring', 'auth_ldap');
                }

                // Check for invalid sAMAccountName characters.
                if (preg_match('#[/\\[\]:;|=,+*?<>@"]#', $extusername)) {
                    print_error ('auth_ldap_ad_invalidchars', 'auth_ldap');
                }

                // First create the user account, and mark it as disabled.
                $newuser['objectClass'] = array('top', 'person', 'user', 'organizationalPerson');
                $newuser['sAMAccountName'] = $extusername;
                $newuser['userAccountControl'] = AUTH_AD_NORMAL_ACCOUNT |
                                                 AUTH_AD_ACCOUNTDISABLE;
                $userdn = 'cn='.ldap_addslashes($extusername).','.$this->config->create_context;
                if (!ldap_add($ldapconnection, $userdn, $newuser)) {
                    print_error('auth_ldap_ad_create_req', 'auth_ldap');
                }

                // Now set the password
                unset($newuser);
                $newuser['unicodePwd'] = mb_convert_encoding('"' . $extpassword . '"',
                                                             'UCS-2LE', 'UTF-8');
                if(!ldap_modify($ldapconnection, $userdn, $newuser)) {
                    // Something went wrong: delete the user account and error out
                    ldap_delete ($ldapconnection, $userdn);
                    print_error('auth_ldap_ad_create_req', 'auth_ldap');
                }
                $uadd = true;
                break;
            default:
               print_error('auth_ldap_unsupportedusertype', 'auth_ldap', '', $this->config->user_type_name);
        }
        $this->ldap_close();
        return $uadd;
    }

    /**
     * Returns true if plugin allows resetting of password from moodle.
     *
     * @return bool
     */
    function can_reset_password() {
        return !empty($this->config->stdchangepassword);
    }

    /**
     * Returns true if plugin can be manually set.
     *
     * @return bool
     */
    function can_be_manually_set() {
        return true;
    }

    /**
     * Returns true if plugin allows signup and user creation.
     *
     * @return bool
     */
    function can_signup() {
        return (!empty($this->config->auth_user_create) and !empty($this->config->create_context));
    }

    /**
     * Sign up a new user ready for confirmation.
     * Password is passed in plaintext.
     *
     * @param object $user new user object
     * @param boolean $notify print notice with link and terminate
     * @return boolean success
     */
    function user_signup($user, $notify=true) {
        global $CFG, $DB, $PAGE, $OUTPUT;

        require_once($CFG->dirroot.'/user/profile/lib.php');
        require_once($CFG->dirroot.'/user/lib.php');

        if ($this->user_exists($user->username)) {
            print_error('auth_ldap_user_exists', 'auth_ldap');
        }

        $plainslashedpassword = $user->password;
        unset($user->password);

        if (! $this->user_create($user, $plainslashedpassword)) {
            print_error('auth_ldap_create_error', 'auth_ldap');
        }

        $user->id = user_create_user($user, false, false);

        user_add_password_history($user->id, $plainslashedpassword);

        // Save any custom profile field information
        profile_save_data($user);

        $userinfo = $this->get_userinfo($user->username);
        $this->update_user_record($user->username, false, false, $this->is_user_suspended((object) $userinfo));

        // This will also update the stored hash to the latest algorithm
        // if the existing hash is using an out-of-date algorithm (or the
        // legacy md5 algorithm).
        update_internal_user_password($user, $plainslashedpassword);

        $user = $DB->get_record('user', array('id'=>$user->id));

        \core\event\user_created::create_from_userid($user->id)->trigger();

        if (! send_confirmation_email($user)) {
            print_error('noemail', 'auth_ldap');
        }

        if ($notify) {
            $emailconfirm = get_string('emailconfirm');
            $PAGE->set_url('/auth/ldap/auth.php');
            $PAGE->navbar->add($emailconfirm);
            $PAGE->set_title($emailconfirm);
            $PAGE->set_heading($emailconfirm);
            echo $OUTPUT->header();
            notice(get_string('emailconfirmsent', '', $user->email), "{$CFG->wwwroot}/index.php");
        } else {
            return true;
        }
    }

    /**
     * Returns true if plugin allows confirming of new users.
     *
     * @return bool
     */
    function can_confirm() {
        return $this->can_signup();
    }

    /**
     * Confirm the new user as registered.
     *
     * @param string $username
     * @param string $confirmsecret
     */
    function user_confirm($username, $confirmsecret) {
        global $DB;

        $user = get_complete_user_data('username', $username);

        if (!empty($user)) {
            if ($user->auth != $this->authtype) {
                return AUTH_CONFIRM_ERROR;

            } else if ($user->secret == $confirmsecret && $user->confirmed) {
                return AUTH_CONFIRM_ALREADY;

            } else if ($user->secret == $confirmsecret) {   // They have provided the secret key to get in
                if (!$this->user_activate($username)) {
                    return AUTH_CONFIRM_FAIL;
                }
                $user->confirmed = 1;
                user_update_user($user, false);
                return AUTH_CONFIRM_OK;
            }
        } else {
            return AUTH_CONFIRM_ERROR;
        }
    }

    /**
     * Return number of days to user password expires
     *
     * If userpassword does not expire it should return 0. If password is already expired
     * it should return negative value.
     *
     * @param mixed $username username
     * @return integer
     */
    function password_expire($username) {
        $result = 0;

        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();
        $user_dn = $this->ldap_find_userdn($ldapconnection, $extusername);
        $search_attribs = array($this->config->expireattr);
        $sr = ldap_read($ldapconnection, $user_dn, '(objectClass=*)', $search_attribs);
        if ($sr)  {
            $info = ldap_get_entries_moodle($ldapconnection, $sr);
            if (!empty ($info)) {
                $info = $info[0];
                if (isset($info[$this->config->expireattr][0])) {
                    $expiretime = $this->ldap_expirationtime2unix($info[$this->config->expireattr][0], $ldapconnection, $user_dn);
                    if ($expiretime != 0) {
                        $now = time();
                        if ($expiretime > $now) {
                            $result = ceil(($expiretime - $now) / DAYSECS);
                        } else {
                            $result = floor(($expiretime - $now) / DAYSECS);
                        }
                    }
                }
            }
        } else {
            error_log($this->errorlogtag.get_string('didtfindexpiretime', 'auth_ldap'));
        }

        return $result;
    }

    /**
     * Syncronizes user fron external LDAP server to moodle user table
     *
     * Sync is now using username attribute.
     *
     * Syncing users removes or suspends users that dont exists anymore in external LDAP.
     * Creates new users and updates coursecreator status of users.
     *
     * @param bool $do_updates will do pull in data updates from LDAP if relevant
     */
    function sync_users($do_updates=true) {
        global $CFG, $DB;

        require_once($CFG->dirroot . '/user/profile/lib.php');

        print_string('connectingldap', 'auth_ldap');
        $ldapconnection = $this->ldap_connect();

        $dbman = $DB->get_manager();

    /// Define table user to be created
        $table = new xmldb_table('tmp_extuser');
        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('username', XMLDB_TYPE_CHAR, '100', null, XMLDB_NOTNULL, null, null);
        $table->add_field('mnethostid', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        $table->add_index('username', XMLDB_INDEX_UNIQUE, array('mnethostid', 'username'));

        print_string('creatingtemptable', 'auth_ldap', 'tmp_extuser');
        $dbman->create_temp_table($table);

        ////
        //// get user's list from ldap to sql in a scalable fashion
        ////
        // prepare some data we'll need
        $filter = '(&('.$this->config->user_attribute.'=*)'.$this->config->objectclass.')';
        $servercontrols = array();

        $contexts = explode(';', $this->config->contexts);

        if (!empty($this->config->create_context)) {
            array_push($contexts, $this->config->create_context);
        }

        $ldappagedresults = ldap_paged_results_supported($this->config->ldap_version, $ldapconnection);
        $ldapcookie = '';
        foreach ($contexts as $context) {
            $context = trim($context);
            if (empty($context)) {
                continue;
            }

            do {
                if ($ldappagedresults) {
                    // TODO: Remove the old branch of code once PHP 7.3.0 becomes required (Moodle 4.1).
                    if (version_compare(PHP_VERSION, '7.3.0', '<')) {
                        // Before 7.3, use this function that was deprecated in PHP 7.4.
                        ldap_control_paged_result($ldapconnection, $this->config->pagesize, true, $ldapcookie);
                    } else {
                        // PHP 7.3 and up, use server controls.
                        $servercontrols = array(array(
                            'oid' => LDAP_CONTROL_PAGEDRESULTS, 'value' => array(
                                'size' => $this->config->pagesize, 'cookie' => $ldapcookie)));
                    }
                }
                if ($this->config->search_sub) {
                    // Use ldap_search to find first user from subtree.
                    // TODO: Remove the old branch of code once PHP 7.3.0 becomes required (Moodle 4.1).
                    if (version_compare(PHP_VERSION, '7.3.0', '<')) {
                        $ldapresult = ldap_search($ldapconnection, $context, $filter, array($this->config->user_attribute));
                    } else {
                        $ldapresult = ldap_search($ldapconnection, $context, $filter, array($this->config->user_attribute),
                            0, -1, -1, LDAP_DEREF_NEVER, $servercontrols);
                    }
                } else {
                    // Search only in this context.
                    // TODO: Remove the old branch of code once PHP 7.3.0 becomes required (Moodle 4.1).
                    if (version_compare(PHP_VERSION, '7.3.0', '<')) {
                        $ldapresult = ldap_list($ldapconnection, $context, $filter, array($this->config->user_attribute));
                    } else {
                        $ldapresult = ldap_list($ldapconnection, $context, $filter, array($this->config->user_attribute),
                            0, -1, -1, LDAP_DEREF_NEVER, $servercontrols);
                    }
                }
                if (!$ldapresult) {
                    continue;
                }
                if ($ldappagedresults) {
                    // Get next server cookie to know if we'll need to continue searching.
                    $ldapcookie = '';
                    // TODO: Remove the old branch of code once PHP 7.3.0 becomes required (Moodle 4.1).
                    if (version_compare(PHP_VERSION, '7.3.0', '<')) {
                        // Before 7.3, use this function that was deprecated in PHP 7.4.
                        $pagedresp = ldap_control_paged_result_response($ldapconnection, $ldapresult, $ldapcookie);
                        // Function ldap_control_paged_result_response() does not overwrite $ldapcookie if it fails, by
                        // setting this to null we avoid an infinite loop.
                        if ($pagedresp === false) {
                            $ldapcookie = null;
                        }
                    } else {
                        // Get next cookie from controls.
                        ldap_parse_result($ldapconnection, $ldapresult, $errcode, $matcheddn,
                            $errmsg, $referrals, $controls);
                        if (isset($controls[LDAP_CONTROL_PAGEDRESULTS]['value']['cookie'])) {
                            $ldapcookie = $controls[LDAP_CONTROL_PAGEDRESULTS]['value']['cookie'];
                        }
                    }
                }
                if ($entry = @ldap_first_entry($ldapconnection, $ldapresult)) {
                    do {
                        $value = ldap_get_values_len($ldapconnection, $entry, $this->config->user_attribute);
                        $value = core_text::convert($value[0], $this->config->ldapencoding, 'utf-8');
                        $value = trim($value);
                        $this->ldap_bulk_insert($value);
                    } while ($entry = ldap_next_entry($ldapconnection, $entry));
                }
                unset($ldapresult); // Free mem.
            } while ($ldappagedresults && $ldapcookie !== null && $ldapcookie != '');
        }

        // If LDAP paged results were used, the current connection must be completely
        // closed and a new one created, to work without paged results from here on.
        if ($ldappagedresults) {
            $this->ldap_close(true);
            $ldapconnection = $this->ldap_connect();
        }

        /// preserve our user database
        /// if the temp table is empty, it probably means that something went wrong, exit
        /// so as to avoid mass deletion of users; which is hard to undo
        $count = $DB->count_records_sql('SELECT COUNT(username) AS count, 1 FROM {tmp_extuser}');
        if ($count < 1) {
            print_string('didntgetusersfromldap', 'auth_ldap');
            $dbman->drop_table($table);
            $this->ldap_close();
            return false;
        } else {
            print_string('gotcountrecordsfromldap', 'auth_ldap', $count);
        }


/// User removal
        // Find users in DB that aren't in ldap -- to be removed!
        // this is still not as scalable (but how often do we mass delete?)

        if ($this->config->removeuser == AUTH_REMOVEUSER_FULLDELETE) {
            $sql = "SELECT u.*
                      FROM {user} u
                 LEFT JOIN {tmp_extuser} e ON (u.username = e.username AND u.mnethostid = e.mnethostid)
                     WHERE u.auth = :auth
                           AND u.deleted = 0
                           AND e.username IS NULL";
            $remove_users = $DB->get_records_sql($sql, array('auth'=>$this->authtype));

            if (!empty($remove_users)) {
                print_string('userentriestoremove', 'auth_ldap', count($remove_users));
                foreach ($remove_users as $user) {
                    if (delete_user($user)) {
                        echo "\t"; print_string('auth_dbdeleteuser', 'auth_db', array('name'=>$user->username, 'id'=>$user->id)); echo "\n";
                    } else {
                        echo "\t"; print_string('auth_dbdeleteusererror', 'auth_db', $user->username); echo "\n";
                    }
                }
            } else {
                print_string('nouserentriestoremove', 'auth_ldap');
            }
            unset($remove_users); // Free mem!

        } else if ($this->config->removeuser == AUTH_REMOVEUSER_SUSPEND) {
            $sql = "SELECT u.*
                      FROM {user} u
                 LEFT JOIN {tmp_extuser} e ON (u.username = e.username AND u.mnethostid = e.mnethostid)
                     WHERE u.auth = :auth
                           AND u.deleted = 0
                           AND u.suspended = 0
                           AND e.username IS NULL";
            $remove_users = $DB->get_records_sql($sql, array('auth'=>$this->authtype));

            if (!empty($remove_users)) {
                print_string('userentriestoremove', 'auth_ldap', count($remove_users));

                foreach ($remove_users as $user) {
                    $updateuser = new stdClass();
                    $updateuser->id = $user->id;
                    $updateuser->suspended = 1;
                    user_update_user($updateuser, false);
                    echo "\t"; print_string('auth_dbsuspenduser', 'auth_db', array('name'=>$user->username, 'id'=>$user->id)); echo "\n";
                    \core\session\manager::kill_user_sessions($user->id);
                }
            } else {
                print_string('nouserentriestoremove', 'auth_ldap');
            }
            unset($remove_users); // Free mem!
        }

/// Revive suspended users
        if (!empty($this->config->removeuser) and $this->config->removeuser == AUTH_REMOVEUSER_SUSPEND) {
            $sql = "SELECT u.id, u.username
                      FROM {user} u
                      JOIN {tmp_extuser} e ON (u.username = e.username AND u.mnethostid = e.mnethostid)
                     WHERE (u.auth = 'nologin' OR (u.auth = ? AND u.suspended = 1)) AND u.deleted = 0";
            // Note: 'nologin' is there for backwards compatibility.
            $revive_users = $DB->get_records_sql($sql, array($this->authtype));

            if (!empty($revive_users)) {
                print_string('userentriestorevive', 'auth_ldap', count($revive_users));

                foreach ($revive_users as $user) {
                    $updateuser = new stdClass();
                    $updateuser->id = $user->id;
                    $updateuser->auth = $this->authtype;
                    $updateuser->suspended = 0;
                    user_update_user($updateuser, false);
                    echo "\t"; print_string('auth_dbreviveduser', 'auth_db', array('name'=>$user->username, 'id'=>$user->id)); echo "\n";
                }
            } else {
                print_string('nouserentriestorevive', 'auth_ldap');
            }

            unset($revive_users);
        }


/// User Updates - time-consuming (optional)
        if ($do_updates) {
            // Narrow down what fields we need to update
            $updatekeys = $this->get_profile_keys();

        } else {
            print_string('noupdatestobedone', 'auth_ldap');
        }
        if ($do_updates and !empty($updatekeys)) { // run updates only if relevant
            $users = $DB->get_records_sql('SELECT u.username, u.id
                                             FROM {user} u
                                            WHERE u.deleted = 0 AND u.auth = ? AND u.mnethostid = ?',
                                          array($this->authtype, $CFG->mnet_localhost_id));
            if (!empty($users)) {
                print_string('userentriestoupdate', 'auth_ldap', count($users));

                $transaction = $DB->start_delegated_transaction();
                $xcount = 0;
                $maxxcount = 100;

                foreach ($users as $user) {
                    echo "\t"; print_string('auth_dbupdatinguser', 'auth_db', array('name'=>$user->username, 'id'=>$user->id));
                    $userinfo = $this->get_userinfo($user->username);
                    if (!$this->update_user_record($user->username, $updatekeys, true,
                            $this->is_user_suspended((object) $userinfo))) {
                        echo ' - '.get_string('skipped');
                    }
                    echo "\n";
                    $xcount++;

                    // Update system roles, if needed.
                    $this->sync_roles($user);
                }
                $transaction->allow_commit();
                unset($users); // free mem
            }
        } else { // end do updates
            print_string('noupdatestobedone', 'auth_ldap');
        }

/// User Additions
        // Find users missing in DB that are in LDAP
        // and gives me a nifty object I don't want.
        // note: we do not care about deleted accounts anymore, this feature was replaced by suspending to nologin auth plugin
        $sql = 'SELECT e.id, e.username
                  FROM {tmp_extuser} e
                  LEFT JOIN {user} u ON (e.username = u.username AND e.mnethostid = u.mnethostid)
                 WHERE u.id IS NULL';
        $add_users = $DB->get_records_sql($sql);

        if (!empty($add_users)) {
            print_string('userentriestoadd', 'auth_ldap', count($add_users));

            $transaction = $DB->start_delegated_transaction();
            foreach ($add_users as $user) {
                $user = $this->get_userinfo_asobj($user->username);

                // Prep a few params
                $user->modified   = time();
                $user->confirmed  = 1;
                $user->auth       = $this->authtype;
                $user->mnethostid = $CFG->mnet_localhost_id;
                // get_userinfo_asobj() might have replaced $user->username with the value
                // from the LDAP server (which can be mixed-case). Make sure it's lowercase
                $user->username = trim(core_text::strtolower($user->username));
                // It isn't possible to just rely on the configured suspension attribute since
                // things like active directory use bit masks, other things using LDAP might
                // do different stuff as well.
                //
                // The cast to int is a workaround for MDL-53959.
                $user->suspended = (int)$this->is_user_suspended($user);
                if (empty($user->lang)) {
                    $user->lang = $CFG->lang;
                }
                if (empty($user->calendartype)) {
                    $user->calendartype = $CFG->calendartype;
                }

                $id = user_create_user($user, false);
                echo "\t"; print_string('auth_dbinsertuser', 'auth_db', array('name'=>$user->username, 'id'=>$id)); echo "\n";
                $euser = $DB->get_record('user', array('id' => $id));

                if (!empty($this->config->forcechangepassword)) {
                    set_user_preference('auth_forcepasswordchange', 1, $id);
                }

                // Save custom profile fields.
                $this->update_user_record($user->username, $this->get_profile_keys(true), false);

                // Add roles if needed.
                $this->sync_roles($euser);

            }
            $transaction->allow_commit();
            unset($add_users); // free mem
        } else {
            print_string('nouserstobeadded', 'auth_ldap');
        }

        $dbman->drop_table($table);
        $this->ldap_close();

        return true;
    }

    /**
     * Bulk insert in SQL's temp table
     */
    function ldap_bulk_insert($username) {
        global $DB, $CFG;

        $username = core_text::strtolower($username); // usernames are __always__ lowercase.
        $DB->insert_record_raw('tmp_extuser', array('username'=>$username,
                                                    'mnethostid'=>$CFG->mnet_localhost_id), false, true);
        echo '.';
    }

    /**
     * Activates (enables) user in external LDAP so user can login
     *
     * @param mixed $username
     * @return boolean result
     */
    function user_activate($username) {
        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();

        $userdn = $this->ldap_find_userdn($ldapconnection, $extusername);
        switch ($this->config->user_type)  {
            case 'edir':
                $newinfo['loginDisabled'] = 'FALSE';
                break;
            case 'rfc2307':
            case 'rfc2307bis':
                // Remember that we add a '*' character in front of the
                // external password string to 'disable' the account. We just
                // need to remove it.
                $sr = ldap_read($ldapconnection, $userdn, '(objectClass=*)',
                                array('userPassword'));
                $info = ldap_get_entries($ldapconnection, $sr);
                $info[0] = array_change_key_case($info[0], CASE_LOWER);
                $newinfo['userPassword'] = ltrim($info[0]['userpassword'][0], '*');
                break;
            case 'ad':
                // We need to unset the ACCOUNTDISABLE bit in the
                // userAccountControl attribute ( see
                // http://support.microsoft.com/kb/305144 )
                $sr = ldap_read($ldapconnection, $userdn, '(objectClass=*)',
                                array('userAccountControl'));
                $info = ldap_get_entries($ldapconnection, $sr);
                $info[0] = array_change_key_case($info[0], CASE_LOWER);
                $newinfo['userAccountControl'] = $info[0]['useraccountcontrol'][0]
                                                 & (~AUTH_AD_ACCOUNTDISABLE);
                break;
            default:
                print_error('user_activatenotsupportusertype', 'auth_ldap', '', $this->config->user_type_name);
        }
        $result = ldap_modify($ldapconnection, $userdn, $newinfo);
        $this->ldap_close();
        return $result;
    }

    /**
     * Returns true if user should be coursecreator.
     *
     * @param mixed $username    username (without system magic quotes)
     * @return mixed result      null if course creators is not configured, boolean otherwise.
     *
     * @deprecated since Moodle 3.4 MDL-30634 - please do not use this function any more.
     */
    function iscreator($username) {
        debugging('iscreator() is deprecated. Please use auth_plugin_ldap::is_role() instead.', DEBUG_DEVELOPER);

        if (empty($this->config->creators) or empty($this->config->memberattribute)) {
            return null;
        }

        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();

        if ($this->config->memberattribute_isdn) {
            if(!($userid = $this->ldap_find_userdn($ldapconnection, $extusername))) {
                return false;
            }
        } else {
            $userid = $extusername;
        }

        $group_dns = explode(';', $this->config->creators);
        $creator = ldap_isgroupmember($ldapconnection, $userid, $group_dns, $this->config->memberattribute);

        $this->ldap_close();

        return $creator;
    }

    /**
     * Check if user has LDAP group membership.
     *
     * Returns true if user should be assigned role.
     *
     * @param mixed $username username (without system magic quotes).
     * @param array $role Array of role's shortname, localname, and settingname for the config value.
     * @return mixed result null if role/LDAP context is not configured, boolean otherwise.
     */
    private function is_role($username, $role) {
        if (empty($this->config->{$role['settingname']}) or empty($this->config->memberattribute)) {
            return null;
        }

        $extusername = core_text::convert($username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();

        if ($this->config->memberattribute_isdn) {
            if (!($userid = $this->ldap_find_userdn($ldapconnection, $extusername))) {
                return false;
            }
        } else {
            $userid = $extusername;
        }

        $groupdns = explode(';', $this->config->{$role['settingname']});
        $isrole = ldap_isgroupmember($ldapconnection, $userid, $groupdns, $this->config->memberattribute);

        $this->ldap_close();

        return $isrole;
    }

    /**
     * Called when the user record is updated.
     *
     * Modifies user in external LDAP server. It takes olduser (before
     * changes) and newuser (after changes) compares information and
     * saves modified information to external LDAP server.
     *
     * @param mixed $olduser     Userobject before modifications    (without system magic quotes)
     * @param mixed $newuser     Userobject new modified userobject (without system magic quotes)
     * @return boolean result
     *
     */
    function user_update($olduser, $newuser) {
        global $CFG;

        require_once($CFG->dirroot . '/user/profile/lib.php');

        if (isset($olduser->username) and isset($newuser->username) and $olduser->username != $newuser->username) {
            error_log($this->errorlogtag.get_string('renamingnotallowed', 'auth_ldap'));
            return false;
        }

        if (isset($olduser->auth) and $olduser->auth != $this->authtype) {
            return true; // just change auth and skip update
        }

        $attrmap = $this->ldap_attributes();
        // Before doing anything else, make sure we really need to update anything
        // in the external LDAP server.
        $update_external = false;
        foreach ($attrmap as $key => $ldapkeys) {
            if (!empty($this->config->{'field_updateremote_'.$key})) {
                $update_external = true;
                break;
            }
        }
        if (!$update_external) {
            return true;
        }

        $extoldusername = core_text::convert($olduser->username, 'utf-8', $this->config->ldapencoding);

        $ldapconnection = $this->ldap_connect();

        $search_attribs = array();
        foreach ($attrmap as $key => $values) {
            if (!is_array($values)) {
                $values = array($values);
            }
            foreach ($values as $value) {
                if (!in_array($value, $search_attribs)) {
                    array_push($search_attribs, $value);
                }
            }
        }

        if(!($user_dn = $this->ldap_find_userdn($ldapconnection, $extoldusername))) {
            return false;
        }

        // Load old custom fields.
        $olduserprofilefields = (array) profile_user_record($olduser->id, false);

        $fields = array();
        foreach (profile_get_custom_fields(false) as $field) {
            $fields[$field->shortname] = $field;
        }

        $success = true;
        $user_info_result = ldap_read($ldapconnection, $user_dn, '(objectClass=*)', $search_attribs);
        if ($user_info_result) {
            $user_entry = ldap_get_entries_moodle($ldapconnection, $user_info_result);
            if (empty($user_entry)) {
                $attribs = join (', ', $search_attribs);
                error_log($this->errorlogtag.get_string('updateusernotfound', 'auth_ldap',
                                                          array('userdn'=>$user_dn,
                                                                'attribs'=>$attribs)));
                return false; // old user not found!
            } else if (count($user_entry) > 1) {
                error_log($this->errorlogtag.get_string('morethanoneuser', 'auth_ldap'));
                return false;
            }

            $user_entry = $user_entry[0];

            foreach ($attrmap as $key => $ldapkeys) {
                if (preg_match('/^profile_field_(.*)$/', $key, $match)) {
                    // Custom field.
                    $fieldname = $match[1];
                    if (isset($fields[$fieldname])) {
                        $class = 'profile_field_' . $fields[$fieldname]->datatype;
                        $formfield = new $class($fields[$fieldname]->id, $olduser->id);
                        $oldvalue = isset($olduserprofilefields[$fieldname]) ? $olduserprofilefields[$fieldname] : null;
                    } else {
                        $oldvalue = null;
                    }
                    $newvalue = $…