twofactor/action/login.php

<?php

/**
 * Two Factor Action Plugin
 *
 * @author Mike Wilmes mwilmes@avc.edu
 * Big thanks to Daniel Popp and his Google 2FA code (authgoogle2fa) as a
 * starting reference.
 *
 * Overview:
 * The plugin provides for two opportunities to perform two factor
 * authentication. The first is on the main login page, via a code provided by
 * an external authenticator. The second is at a separate prompt after the
 * initial login. By default, all modules will process from the second login,
 * but a module can subscribe to accepting a password from the main login when
 * it makes sense, because the user has access to the code in advance.
 *
 * If a user only has configured modules that provide for login at the main
 * screen, the code will only be accepted at the main login screen for
 * security purposes.
 *
 * Modules will be called to render their configuration forms on the profile
 * page and to verify a user's submitted code. If any module accepts the
 * submitted code, then the user is granted access.
 *
 * Each module may be used to transmit a message to the user that their
 * account has been logged into. One module may be used as the default
 * transmit option. These options are handled by the parent module.
 */

// Create a definition for a 2FA cookie.
use dokuwiki\plugin\twofactor\Manager;

class action_plugin_twofactor_login extends DokuWiki_Action_Plugin
{
    const TWOFACTOR_COOKIE = '2FA' . DOKU_COOKIE;

    /** @var Manager */
    protected $manager;

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->manager = Manager::getInstance();
    }

    /**
     * Registers the event handlers.
     */
    public function register(Doku_Event_Handler $controller)
    {
        if (!(Manager::getInstance())->isReady()) return;

        // check 2fa requirements and either move to profile or login handling
        $controller->register_hook(
            'ACTION_ACT_PREPROCESS',
            'BEFORE',
            $this,
            'handleActionPreProcess',
            null,
            -999999
        );

        // display login form
        $controller->register_hook(
            'TPL_ACT_UNKNOWN',
            'BEFORE',
            $this,
            'handleLoginDisplay'
        );

        // FIXME disable user in all non-main screens (media, detail, ajax, ...)

        /*
        $controller->register_hook('HTML_LOGINFORM_OUTPUT', 'BEFORE', $this, 'twofactor_login_form');

        // Manage action flow around the twofactor authentication requirements.

        // Handle the twofactor login and profile actions.
        $controller->register_hook('TPL_ACT_UNKNOWN', 'BEFORE', $this, 'twofactor_handle_unknown_action');
        $controller->register_hook('TPL_ACTION_GET', 'BEFORE', $this, 'twofactor_get_unknown_action');

        // If the user supplies a token code at login, checks it before logging the user in.
        $controller->register_hook('AUTH_LOGIN_CHECK', 'BEFORE', $this, 'twofactor_before_auth_check', null,
            -999999);
        // Atempts to process the second login if the user hasn't done so already.
        $controller->register_hook('AUTH_LOGIN_CHECK', 'AFTER', $this, 'twofactor_after_auth_check');
        $this->log('register: Session: ' . print_r($_SESSION, true), self::LOGGING_DEBUGPLUS);
        */
    }

    /**
     * Decide if any 2fa handling needs to be done for the current user
     *
     * @param Doku_Event $event
     */
    public function handleActionPreProcess(Doku_Event $event)
    {
        if (!$this->manager->getUser()) return;

        global $INPUT;

        // already in a 2fa login?
        if ($event->data === 'twofactor_login') {
            if ($this->verify(
                $INPUT->str('2fa_code'),
                $INPUT->str('2fa_provider'),
                $INPUT->bool('sticky')
            )) {
                $event->data = 'show';
                return;
            } else {
                // show form
                $event->preventDefault();
                return;
            }
        }

        // authed already, continue
        if ($this->isAuthed()) {
            return;
        }

        if (count($this->manager->getUserProviders())) {
            // user has already 2fa set up - they need to authenticate before anything else
            $event->data = 'twofactor_login';
            $event->preventDefault();
            $event->stopPropagation();
            return;
        }

        if ($this->manager->isRequired()) {
            // 2fa is required - they need to set it up now
            // this will be handled by action/profile.php
            $event->data = 'twofactor_profile';
        }

        // all good. proceed
    }

    /**
     * Show a 2fa login screen
     *
     * @param Doku_Event $event
     */
    public function handleLoginDisplay(Doku_Event $event)
    {
        if ($event->data !== 'twofactor_login') return;
        $event->preventDefault();
        $event->stopPropagation();

        global $INPUT;
        $providerID = $INPUT->str('2fa_provider');
        $providers = $this->manager->getUserProviders();
        if (isset($providers[$providerID])) {
            $provider = $providers[$providerID];
            unset($providers[$providerID]);
        } else {
            $provider = array_shift($providers);
        }

        $form = new dokuwiki\Form\Form(['method' => 'POST']);
        $form->setHiddenField('do', 'twofactor_login');
        $form->setHiddenField('2fa_provider', $provider->getProviderID());
        $form->addFieldsetOpen($provider->getLabel());
        try {
            $code = $provider->generateCode();
            $info = $provider->transmitMessage($code);
            $form->addHTML('<p>' . hsc($info) . '</p>');
            $form->addTextInput('2fa_code', 'Your Code')->val('');
            $form->addCheckbox('sticky', 'Remember this browser'); // reuse same name as login
            $form->addButton('2fa', 'Submit')->attr('type', 'submit');
        } catch (\Exception $e) {
            msg(hsc($e->getMessage()), -1); // FIXME better handling
        }
        $form->addFieldsetClose();

        if (count($providers)) {
            $form->addFieldsetOpen('Alternative methods');
            foreach ($providers as $prov) {
                $link = $prov->getProviderID(); // FIXME build correct links

                $form->addHTML($link);
            }
            $form->addFieldsetClose();
        }

        echo $form->toHTML();
    }

    /**
     * Has the user already authenticated with the second factor?
     * @return bool
     */
    protected function isAuthed()
    {
        if (!isset($_COOKIE[self::TWOFACTOR_COOKIE])) return false;
        $data = unserialize(base64_decode($_COOKIE[self::TWOFACTOR_COOKIE]));
        if (!is_array($data)) return false;
        list($providerID, $buid,) = $data;
        if (auth_browseruid() !== $buid) return false;

        try {
            // ensure it's a still valid provider
            $this->manager->getUserProvider($providerID);
            return true;
        } catch (\Exception $e) {
            return false;
        }
    }

    /**
     * Verify a given code
     *
     * @return bool
     * @throws Exception
     */
    protected function verify($code, $providerID, $sticky)
    {
        global $conf;

        if (!$code) return false;
        if (!$providerID) return false;
        $provider = $this->manager->getUserProvider($providerID);
        $ok = $provider->checkCode($code);
        if (!$ok) {
            msg('code was wrong', -1);
            return false;
        }

        // store cookie
        $data = base64_encode(serialize([$providerID, auth_browseruid(), time()]));
        $cookieDir = empty($conf['cookiedir']) ? DOKU_REL : $conf['cookiedir'];
        $time = $sticky ? (time() + 60 * 60 * 24 * 365) : 0; //one year
        setcookie(self::TWOFACTOR_COOKIE, $data, $time, $cookieDir, '', ($conf['securecookie'] && is_ssl()), true);

        return true;
    }


    // region old shit

    /**
     * Handles the login form rendering.
     */
    public function twofactor_login_form(&$event, $param)
    {
        $this->log('twofactor_login_form: start', self::LOGGING_DEBUG);
        $twofa_form = form_makeTextField('otp', '', $this->getLang('twofactor_login'), '', 'block',
            array('size' => '50', 'autocomplete' => 'off'));
        $pos = $event->data->findElementByAttribute('name', 'p');
        $event->data->insertElement($pos + 1, $twofa_form);
    }

    /**
     * Action process redirector.  If logging out, processes the logout
     * function.  If visiting the profile, sets a flag to confirm that the
     * profile is being viewed in order to enable OTP attribute updates.
     */
    public function twofactor_action_process_handler(&$event, $param)
    {
        global $USERINFO, $ID, $INFO, $INPUT;
        $this->log('twofactor_action_process_handler: start ' . $event->data, self::LOGGING_DEBUG);
        // Handle logout.
        if ($event->data == 'logout') {
            $this->_logout();
            return;
        }
        // Handle main login.
        if ($event->data == 'login') {
            // To support loglog or any other module that hooks login checking for success,
            // Confirm that the user is logged in.  If not, then redirect to twofactor_login
            // and fail the login.
            if ($USERINFO && !$this->get_clearance()) {
                // Hijack this event.  We need to resend it after 2FA is done.
                $event->stopPropagation();
                // Send loglog an event to show the user logged in but needs OTP code.
                $log = array('message' => 'logged in, ' . $this->getLang('requires_otp'), 'user' => $user);
                trigger_event('PLUGIN_LOGLOG_LOG', $log);
            }
            return;
        }

        // Check to see if we are heading to the twofactor login.
        if ($event->data == 'twofactor_login') {
            // Check if we already have clearance- just in case.
            if ($this->get_clearance()) {
                // Okay, this continues on with normal processing.
                return;
            }
            // We will be handling this action's permissions here.
            $event->preventDefault();
            $event->stopPropagation();
            // If not logged into the main auth plugin then send there.
            if (!$USERINFO) {
                $event->result = false;
                send_redirect(wl($ID, array('do' => 'login'), true, '&'));
                return;
            }
            if (count($this->otpMods) == 0) {
                $this->log('No available otp modules.', self::LOGGING_DEBUG);
                // There is no way to handle this login.
                msg($this->getLang('mustusetoken'), -1);
                $event->result = false;
                send_redirect(wl($ID, array('do' => 'logout'), true, '&'));
                return;
            }
            // Otherwise handle the action.
            $act = $this->_process_otp($event, $param);
            $event->result = true;
            if ($act) {
                send_redirect(wl($ID, array('do' => $act), true, '&'));
            }
            return;
        }

        // Is the user logged into the wiki?
        if (!$USERINFO) {
            // If not logged in, then do nothing.
            return;
        }

        // See if this user has any OTP methods configured.
        $available = count($this->tokenMods) + count($this->otpMods) > 0;
        // Check if this user needs to login with 2FA.
        // Wiki mandatory is on if user is logged in and config is mandatory
        $mandatory = $this->getConf("optinout") == 'mandatory' && $INPUT->server->str('REMOTE_USER', '');
        // User is NOT OPTED OUT if the optin setting is undefined and the wiki config is optout.
        $not_opted_out = $this->attribute->get("twofactor", "state") == '' && $this->getConf("optinout") == 'optout';
        // The user must login if wiki mandatory is on or if the user is logged in and user is opt in.
        $must_login = $mandatory || ($this->attribute->get("twofactor",
                    "state") == 'in' && $INPUT->server->str('REMOTE_USER', ''));
        $has_clearance = $this->get_clearance() === true;
        $this->log('twofactor_action_process_handler: USERINFO: ' . print_r($USERINFO, true), self::LOGGING_DEBUGPLUS);

        // Possible combination skipped- not logged in and 2FA is not requred for user {optout conf or (no selection and optin conf)}.

        // Check to see if updating twofactor is required.
        // This happens if the wiki is mandatory, the user has not opted out of an opt-out wiki, or if the user has opted in, and if there are no available mods for use.
        // The user cannot have available mods without setting them up, and cannot unless the wiki is mandatory or the user has opted in.
        if (($must_login || $not_opted_out) && !$available) {
            // If the user has not been granted access at this point, do so or they will get booted after setting up 2FA.
            if (!$has_clearance) {
                $this->_grant_clearance();
            }
            // We need to go to the twofactor profile.
            // If we were setup properly, we would not be here in the code.
            $event->preventDefault();
            $event->stopPropagation();
            $event->result = false;
            // Send loglog an event to show the user aborted 2FA.
            $log = array('message' => 'logged in, ' . $this->getLang('2fa_mandatory'), 'user' => $user);
            trigger_event('PLUGIN_LOGLOG_LOG', $log);
            send_redirect(wl($ID, array('do' => 'twofactor_profile'), true, '&'));
            return;
        }

        // Now validate login before proceeding.
        if (!$has_clearance) {
            if ($must_login) {
                if (!in_array($event->data, array('login', 'twofactor_login'))) {
                    // If not logged in then force to the login page.
                    $event->preventDefault();
                    $event->stopPropagation();
                    $event->result = false;
                    // If there are OTP generators, then use them.
                    send_redirect(wl($ID, array('do' => 'twofactor_login'), true, '&'));
                    return;
                }
                // Otherwise go to where we are told.
                return;
            }
            // The user is not set with 2FA and is not required to.
            // Grant clearance and continue.
            $this->_grant_clearance();
        }
        // Otherwise everything is good!
        return;
    }

    public function twofactor_handle_unknown_action(Doku_Event $event, $param)
    {
        if ($event->data == 'twofactor_login') {
            $event->preventDefault();
            $event->stopPropagation();
            $event->result = $this->twofactor_otp_login($event, $param);
            return;
        }
    }

    public function twofactor_get_unknown_action(&$event, $param)
    {
        $this->log('start: twofactor_before_auth_check', self::LOGGING_DEBUG);
        switch ($event->data['type']) {
            case 'twofactor_profile':
                $event->data['params'] = array('do' => 'twofactor_profile');
                // Inject text into $lang.
                global $lang;
                $lang['btn_twofactor_profile'] = $this->getLang('btn_twofactor_profile');
                $event->preventDefault();
                $event->stopPropagation();
                $event->result = false;
                break;
        }
    }

    /**
     * Logout this session from two factor authentication.  Purge any existing
     * OTP from the user's attributes.
     */
    private function _logout()
    {
        global $conf, $INPUT;
        $this->log('_logout: start', self::LOGGING_DEBUG);
        $this->log(print_r(array($_SESSION, $_COOKIE), true), self::LOGGING_DEBUGPLUS);
        // No need to do this as long as no Cookie or session for login is present!
        if (empty($_SESSION[DOKU_COOKIE]['twofactor_clearance']) && empty($_COOKIE[TWOFACTOR_COOKIE])) {
            $this->log('_logout: quitting, no cookies', self::LOGGING_DEBUG);
            return;
        }
        // Audit log.
        $this->log("2FA Logout: " . $INPUT->server->str('REMOTE_USER', $_REQUEST['r']), self::LOGGING_AUDIT);
        if ($this->attribute) {
            // Purge outstanding OTPs.
            $this->attribute->del("twofactor", "otp");
            // Purge cookie and session ID relation.
            $key = $_COOKIE[TWOFACTOR_COOKIE];
            if (!empty($key) && substr($key, 0, 3) != 'id.') {
                $id = $this->attribute->del("twofactor", $key);
            }
            // Wipe out 2FA cookie.
            $this->log('del cookies: ' . TWOFACTOR_COOKIE . ' ' . print_r(headers_sent(), true),
                self::LOGGING_DEBUGPLUS);
            $cookie = '';
            $cookieDir = empty($conf['cookiedir']) ? DOKU_REL : $conf['cookiedir'];
            $time = time() - 600000; //many seconds ago
            setcookie(TWOFACTOR_COOKIE, $cookie, $time, $cookieDir, '', ($conf['securecookie'] && is_ssl()), true);
            unset($_COOKIE[TWOFACTOR_COOKIE]);
            // Just in case, unset the setTime flag so attributes will be saved again.
            $this->setTime = false;
        }
        // Before we get here, the session is closed. Reopen it to logout the user.
        if (!headers_sent()) {
            $session = session_status() != PHP_SESSION_NONE;
            if (!$session) {
                session_start();
            }
            $_SESSION[DOKU_COOKIE]['twofactor_clearance'] = false;
            unset($_SESSION[DOKU_COOKIE]['twofactor_clearance']);
            if (!$session) {
                session_write_close();
            }
        } else {
            msg("Error! You have not been logged off!!!", -1);
        }
    }

    /**
     * See if the current session has passed two factor authentication.
     * @return bool - true if the session as successfully passed two factor
     *      authentication.
     */
    public function get_clearance($user = null)
    {
        global $INPUT;
        $this->log("get_clearance: start", self::LOGGING_DEBUG);
        $this->log("User:" . $INPUT->server->str('REMOTE_USER', null), self::LOGGING_DEBUGPLUS);
        # Get and correct the refresh expiry.
        # At least 5 min, at most 1440 min (1 day).
        $refreshexpiry = min(max($this->getConf('refreshexpiry'), 5), 1400) * 60;
        # First check if we have a key.  No key === no login.
        $key = $_COOKIE[TWOFACTOR_COOKIE];
        if (empty($key)) {
            $this->log("get_clearance: No cookie.", self::LOGGING_DEBUGPLUS);
            return false;
        }
        # If the key is not valid, logout.
        if (substr($key, 0, 3) != 'id.') {
            $this->log("get_clearance: BAD cookie.", self::LOGGING_DEBUGPLUS);
            // Purge the login data just in case.
            $this->_logout();
            return false;
        }
        # Load the expiry value from session.
        $expiry = $_SESSION[DOKU_COOKIE]['twofactor_clearance'];
        # Check if this time is valid.
        $clearance = (!empty($expiry) && $expiry + $refreshexpiry > time());
        if (!$clearance) {
            # First use this time to purge the old IDs from attribute.
            foreach (array_filter($this->attribute->enumerateAttributes("twofactor", $user), function ($key) {
                substr($key, 0, 3) == 'id.';
            }) as $attr) {
                if ($this->attribute->get("twofactor", $attr, $user) + $refreshexpiry < time()) {
                    $this->attribute->del("twofactor", $attr, $user);
                }
            }
            # Check if this key still exists.
            $clearance = $this->attribute->exists("twofactor", $key, $user);
            if ($clearance) {
                $this->log("get_clearance: 2FA revived by cookie. Expiry: " . print_r($expiry,
                        true) . " Session: " . print_r($_SESSION, true), self::LOGGING_DEBUGPLUS);
            }
        }
        if ($clearance && !$this->setTime) {
            $session = session_status() != PHP_SESSION_NONE;
            if (!$session) {
                session_start();
            }
            $_SESSION[DOKU_COOKIE]['twofactor_clearance'] = time();
            if (!$session) {
                session_write_close();
            }
            $this->attribute->set("twofactor", $key, $_SESSION[DOKU_COOKIE]['twofactor_clearance'], $user);
            // Set this flag to stop future updates.
            $this->setTime = true;
            $this->log("get_clearance: Session reset. Session: " . print_r($_SESSION, true), self::LOGGING_DEBUGPLUS);
        } elseif (!$clearance) {
            // Otherwise logout.
            $this->_logout();
        }
        return $clearance;
    }

    /**
     * Flags this session as having passed two factor authentication.
     * @return bool - returns true on successfully granting two factor clearance.
     */
    private function _grant_clearance($user = null)
    {
        global $conf, $INPUT;
        $this->log("_grant_clearance: start", self::LOGGING_DEBUG);
        $this->log('2FA Login: ' . $INPUT->server->str("REMOTE_USER", $user), self::LOGGING_AUDIT);
        if ($INPUT->server->str("REMOTE_USER", $user) == 1) {
            $this->log("_grant_clearance: start", self::LOGGING_DEBUGPLUS);
        }
        // Purge the otp code as a security measure.
        $this->attribute->del("twofactor", "otp", $user);
        if (!headers_sent()) {
            $session = session_status() != PHP_SESSION_NONE;
            if (!$session) {
                session_start();
            }
            $_SESSION[DOKU_COOKIE]['twofactor_clearance'] = time();
            // Set the notify flag if set or required by wiki.
            $this->log('_grant_clearance: conf:' . $this->getConf('loginnotice') . ' user:' . ($this->attribute->get("twofactor",
                    "loginnotice", $user) === true ? 'true' : 'false'), self::LOGGING_DEBUG);
            $send_wanted = $this->getConf('loginnotice') == 'always' || ($this->getConf('loginnotice') == 'user' && $this->attribute->get("twofactor",
                        "loginnotice", $user) == true);
            if ($send_wanted) {
                $_SESSION[DOKU_COOKIE]['twofactor_notify'] = true;
            }
            if (!$session) {
                session_write_close();
            }
        } else {
            msg("Error! You have not been logged in!!!", -1);
        }
        // Creating a cookie in case the session purges.
        $key = 'id.' . session_id();
        // Storing a timeout value.
        $this->attribute->set("twofactor", $key, $_SESSION[DOKU_COOKIE]['twofactor_clearance'], $user);
        // Set the 2FA cookie.
        $this->log('_grant_clearance: new cookies: ' . TWOFACTOR_COOKIE . ' ' . print_r(headers_sent(), true),
            self::LOGGING_DEBUGPLUS);
        $cookieDir = empty($conf['cookiedir']) ? DOKU_REL : $conf['cookiedir'];
        $time = time() + 60 * 60 * 24 * 365; //one year
        setcookie(TWOFACTOR_COOKIE, $key, $time, $cookieDir, '', ($conf['securecookie'] && is_ssl()), true);
        $_COOKIE[TWOFACTOR_COOKIE] = $key;
        return !empty($_SESSION[DOKU_COOKIE]['twofactor_clearance']);
    }

    /**
     * Sends emails notifying user of successfult 2FA login.
     * @return mixed - returns true on successfully sending notification to all
     *     modules, false if no notifications were sent, or a number indicating
     *     the number of modules that suceeded.
     */
    private function _send_login_notification()
    {
        $this->log("_send_login_notification: start", self::LOGGING_DEBUG);
        // Send login notification.
        $module = $this->attribute->exists("twofactor", "defaultmod") ? $this->attribute->get("twofactor",
            "defaultmod") : null;
        $subject = $this->getConf('loginsubject');
        $time = date(DATE_RFC2822);
        $message = str_replace('$time', $time, $this->getConf('logincontent'));
        $result = $this->_send_message($subject, $message, $module);
        return $result;
    }

    /**
     * Handles the authentication check. Screens Google Authenticator OTP, if available.
     * NOTE: NOT LOGGED IN YET. Attribute requires user name.
     */
    function twofactor_before_auth_check(&$event, $param)
    {
        global $ACT, $INPUT;
        $this->log("twofactor_before_auth_check: start $ACT", self::LOGGING_DEBUG);
        $this->log("twofactor_before_auth_check: Cookie: " . print_r($_COOKIE, true), self::LOGGING_DEBUGPLUS);
        // Only operate if this is a login.
        if ($ACT !== 'login') {
            return;
        }
        // If there is no supplied username, then there is nothing to check at this time.
        if (!$event->data['user']) {
            return;
        }
        $user = $INPUT->server->str('REMOTE_USER', $event->data['user']);
        // Set helper variables here.
        $this->_setHelperVariables($user);
        // If the user still has clearance, then we can skip this.
        if ($this->get_clearance($user)) {
            return;
        }
        // Allow the user to try to use login tokens, even if the account cannot use them.
        $otp = $INPUT->str('otp', '');
        if ($otp !== '') {
            // Check for any modules that support OTP at login and are ready for use.
            foreach ($this->tokenMods as $mod) {
                $result = $mod->processLogin($otp, $user);
                if ($result) {
                    // The OTP code was valid.
                    $this->_grant_clearance($user);
                    // Send loglog an event to show the user logged in using a token.
                    $log = array('message' => 'logged in ' . $this->getLang('token_ok'), 'user' => $user);
                    trigger_event('PLUGIN_LOGLOG_LOG', $log);
                    return;
                }
            }
            global $lang;
            msg($lang['badlogin'], -1);
            $event->preventDefault();
            $event->result = false;
            // Send loglog an event to show the failure
            if (count($this->tokenMods) == 0) {
                $log = array('message' => 'failed ' . $this->getLang('no_tokens'), 'user' => $user);
            } else {
                $log = array('message' => 'failed ' . $this->getLang('token_mismatch'), 'user' => $user);
            }
            trigger_event('PLUGIN_LOGLOG_LOG', $log);
            return;
        }
        // No GA OTP was supplied.
        // If the user has no modules available, then grant access.
        // The action preprocessing will send the user to the profile if needed.
        $available = count($this->tokenMods) + count($this->otpMods) > 0;
        $this->log('twofactor_before_auth_check: Tokens:' . count($this->tokenMods) . ' Codes:' . count($this->otpMods) . " Available:" . (int)$available,
            self::LOGGING_DEBUGPLUS);
        if (!$available) {
            // The user could not authenticate if they wanted to.
            // Set this so they don't get auth prompted while setting up 2FA.
            $this->_grant_clearance($user);
            return;
        }
        // At this point, the user has a working module.
        // If the only working module is for a token, then fail.
        if (count($this->otpMods) == 0) {
            msg($this->getLang('mustusetoken'), -1);
            $event->preventDefault();
            return;
        }
        // The user is logged in to auth, but not into twofactor.
        // The redirection handler will send the user to the twofactor login.
        return;
    }

    /**
     * @param $event
     * @param $param
     */
    function twofactor_after_auth_check(&$event, $param)
    {
        global $ACT;
        global $INPUT;
        $this->log("twofactor_after_auth_check: start", self::LOGGING_DEBUG);
        // Check if the action was login.
        if ($ACT == 'login') {
            // If there *was* no one logged in, then purge 2FA tokens.
            if ($INPUT->server->str('REMOTE_USER', '') == '') {
                $this->_logout();
                // If someone *just* logged in, then fire off a log.
                if ($event->data['user']) {
                    // Send loglog an event to show the user logged in but needs OTP code.
                    $log = array(
                        'message' => 'logged in, ' . $this->getLang('requires_otp'),
                        'user' => $event->data['user'],
                    );
                    trigger_event('PLUGIN_LOGLOG_LOG', $log);
                }
                return;
            }
        }
        // Update helper variables here since we are logged in.
        $this->_setHelperVariables();
        // If set, then send login notification and clear flag.
        if ($_SESSION[DOKU_COOKIE]['twofactor_notify'] == true) {
            // Set the clear flag if no messages can be sent or if the result is not false.
            $clear = count($this_ > otpMods) > 0 || $this->_send_login_notification() !== false;
            if ($clear) {
                unset($_SESSION[DOKU_COOKIE]['twofactor_notify']);
            }
        }
        return;
    }

    /* Returns action to take. */
    private function _process_otp(&$event, $param)
    {
        global $ACT, $ID, $INPUT;
        $this->log("_process_otp: start", self::LOGGING_DEBUG);
        // Get the logged in user.
        $user = $INPUT->server->str('REMOTE_USER');
        // See if the user is quitting OTP.  We don't call it logoff because we don't want the user to think they are logged in!
        // This has to be checked before the template is started.
        if ($INPUT->has('otpquit')) {
            // Send loglog an event to show the user aborted 2FA.
            $log = array('message' => 'logged off, ' . $this->getLang('quit_otp'), 'user' => $user);
            trigger_event('PLUGIN_LOGLOG_LOG', $log);
            // Redirect to logout.
            return 'logout';
        }
        // Check if the user asked to generate and resend the OTP.
        if ($INPUT->has('resend')) {
            if ($INPUT->has('useall')) {
                $defaultMod = null;
            } else {
                $defaultMod = $this->attribute->exists("twofactor", "defaultmod") ? $this->attribute->get("twofactor",
                    "defaultmod") : null;
            }
            // At this point, try to send the OTP.
            $mod = array_key_exists($defaultMod, $this->otpMods) ? $this->otpMods[$defaultMod] : null;
            $this->_send_otp($mod);
            return;
        }
        // If a OTP has been submitted by the user, then verify the OTP.
        // If verified, then grant clearance and continue normally.
        $otp = $INPUT->str('otpcode');
        if ($otp) {
            foreach ($this->otpMods as $mod) {
                $result = $mod->processLogin($otp);
                if ($result) {
                    // The OTP code was valid.
                    $this->_grant_clearance();
                    // Send loglog an event to show the user passed 2FA.
                    $log = array('message' => 'logged in ' . $this->getLang('otp_ok'), 'user' => $user);
                    trigger_event('PLUGIN_LOGLOG_LOG', $log);
                    /*
                    // This bypasses sending any further events to other modules for the login we stole earlier.
                    return 'show';
                    */
                    // This will trigger the login events again.  However, this is to ensure
                    // that other modules work correctly because we hijacked this event earlier.
                    return 'login';
                }
            }
            // Send loglog an event to show the user entered the wrong OTP code.
            $log = array('message' => 'failed OTP login, ' . $this->getLang('otp_mismatch'), 'user' => $user);
            trigger_event('PLUGIN_LOGLOG_LOG', $log);
            msg($this->getLang('twofactor_invalidotp'), -1);
        }
        return;
    }

    /**
     * Process any updates to two factor settings.
     */
    private function _process_changes(&$event, $param)
    {
        // If the plugin is disabled, then exit.
        $this->log("_process_changes: start", self::LOGGING_DEBUG);
        $changed = false;
        global $INPUT, $USERINFO, $conf, $auth, $lang, $ACT;
        if (!$INPUT->has('save')) {
            return;
        }
        // In needed, verify password.
        if ($conf['profileconfirm']) {
            if (!$auth->checkPass($INPUT->server->str('REMOTE_USER'), $INPUT->post->str('oldpass'))) {
                msg($lang['badpassconfirm'], -1);
                return;
            }
        }
        // Process opt in/out.
        if ($this->getConf("optinout") != 'mandatory') {
            $oldoptinout = $this->attribute->get("twofactor", "state");
            $optinout = $INPUT->bool('optinout', false) ? 'in' : 'out';
            if ($oldoptinout != $optinout) {
                $this->attribute->set("twofactor", "state", $optinout);
                $changed = true;
            }
        }
        // Process notifications.
        if ($this->getConf("loginnotice") == 'user') {
            $oldloginnotice = $this->attribute->get("twofactor", "loginnotice");
            $loginnotice = $INPUT->bool('loginnotice', false);
            if ($oldloginnotice != $loginnotice) {
                $this->attribute->set("twofactor", "loginnotice", $loginnotice);
                $changed = true;
            }
        }
        // Process default module.
        $defaultmodule = $INPUT->str('default_module', '');
        if ($defaultmodule) {
            if ($defaultmodule === $this->getLang('useallotp')) {
                // Set to use ALL OTP channels.
                $this->attribute->set("twofactor", "defaultmod", null);
                $changed = true;
            } else {
                $useableMods = array();
                foreach ($this->modules as $name => $mod) {
                    if (!$mod->canAuthLogin() && $mod->canUse()) {
                        $useableMods[$mod->getLang("name")] = $mod;
                    }
                }
                if (array_key_exists($defaultmodule, $useableMods)) {
                    $this->attribute->set("twofactor", "defaultmod", $defaultmodule);
                    $changed = true;
                }
            }
        }
        // Update module settings.
        $sendotp = null;
        foreach ($this->modules as $name => $mod) {
            $this->log('_process_changes: processing ' . get_class($mod) . '::processProfileForm()',
                self::LOGGING_DEBUG);
            $result = $mod->processProfileForm();
            $this->log('_process_changes: processing ' . get_class($mod) . '::processProfileForm() == ' . $result,
                self::LOGGING_DEBUGPLUS);
            // false:change failed  'failed':OTP failed  null: no change made
            $changed |= $result !== false && $result !== 'failed' && $result !== null;
            switch ((string)$result) {
                case 'verified':
                    // Remove used OTP.
                    $this->attribute->del("twofactor", "otp");
                    msg($mod->getLang('passedsetup'), 1);
                    // Reset helper variables.
                    $this->_setHelperVariables();
                    $this->log("2FA Added: " . $INPUT->server->str('REMOTE_USER', '') . ' ' . get_class($mod),
                        self::LOGGING_AUDIT);
                    break;
                case 'failed':
                    msg($mod->getLang('failedsetup'), -1);
                    break;
                case 'otp':
                    if (!$sendotp) {
                        $sendotp = $mod;
                    }
                    break;
                case 'deleted':
                    $this->log("2FA Removed: " . $INPUT->server->str('REMOTE_USER', '') . ' ' . get_class($mod),
                        self::LOGGING_AUDIT);
                    // Reset helper variables.
                    $this->_setHelperVariables();
                    break;
            }
        }
        // Send OTP if requested.
        if (is_object($sendotp)) {
            // Force the message since it will fail the canUse function.
            if ($this->_send_otp($sendotp, true)) {
                msg($sendotp->getLang('needsetup'), 1);
            } else {
                msg("Could not send message using " . get_class($sendotp), -1);
            }
        }
        // Update change status if changed.
        if ($changed) {
            // If there were any changes, update the available tokens accordingly.
            $this->_setHelperVariables();
            msg($this->getLang('updated'), 1);
        }
        return true;
    }

    /**
     * Handles the email and text OTP options.
     * NOTE: The user will be technically logged in at this point.  This module will rewrite the
     * page with the prompt for the OTP until validated or the user logs out.
     */
    function twofactor_otp_login(&$event, $param)
    {
        $this->log("twofactor_otp_login: start", self::LOGGING_DEBUG);
        // Skip this if not logged in or already two factor authenticated.
        // Ensure the OTP exists and is still valid. If we need to, send a OTP.
        $otpQuery = $this->get_otp_code();
        if ($otpQuery == false) {
            $useableMods = array();
            foreach ($this->modules as $name => $mod) {
                if (!$mod->canAuthLogin() && $mod->canUse()) {
                    $useableMods[$mod->getLang("name")] = $mod;
                }
            }
            $defaultMod = $this->attribute->exists("twofactor", "defaultmod") ? $this->attribute->get("twofactor",
                "defaultmod") : null;
            $mod = array_key_exists($defaultMod, $useableMods) ? $useableMods[$defaultMod] : null;
            $this->_send_otp($mod);
        }
        // Generate the form to login.
        // If we are here, then only provide options to accept the OTP or to logout.
        global $lang;
        $form = new Doku_Form(array('id' => 'otp_setup'));
        $form->startFieldset($this->getLang('twofactor_otplogin'));
        $form->addElement(form_makeTextField('otpcode', '', $this->getLang('twofactor_otplogin'), '', 'block',
            array('size' => '50', 'autocomplete' => 'off')));
        $form->addElement(form_makeButton('submit', '', $this->getLang('btn_login')));
        $form->addElement(form_makeTag('br'));
        $form->addElement(form_makeCheckboxField('useall', '1', $this->getLang('twofactor_useallmods'), '', 'block'));
        $form->addElement(form_makeTag('br'));
        $form->addElement(form_makeButton('submit', '', $this->getLang('btn_resend'), array('name' => 'resend')));
        $form->addElement(form_makeButton('submit', '', $this->getLang('btn_quit'), array('name' => 'otpquit')));
        $form->endFieldset();
        echo '<div class="centeralign">' . NL . $form->getForm() . '</div>' . NL;
    }

    /**
     * Sends a message using configured modules.
     * If $module is set to a specific instance, that instance will be used to
     * send the message. If not supplied or null, then all configured modules
     * will be used to send the message. $module can also be an array of
     * selected modules.
     * If $force is true, then will try to send the message even if the module
     * has not been validated.
     * @return array(array, mixed) - The first item in the array is an array
     *     of all modules that the message was successfully sent by.  The
     *     second item is true if successfull to all attempted tramsmission
     *     modules, false if all failed, and a number of how many successes
     *     if only some modules failed.
     */
    private function _send_message($subject, $message, $module = null, $force = false)
    {
        global $INPUT;
        $this->log("_send_message: start", self::LOGGING_DEBUG);
        if ($module === null) {
            $module = $this->otpMods;
        }
        if (!is_array($module)) {
            $module = array($module);
        }
        if (count($module) >= 1) {
            $modulekeys = array_keys($module);
            $modulekey = $modulekeys[0];
            $modname = get_class($module[$modulekey]);
        } else {
            $modname = null;
        }
        // Attempt to deliver messages.
        $user = $INPUT->server->str('REMOTE_USER', '*unknown*');
        $success = 0;
        $modname = array();
        foreach ($module as $mod) {
            if ($mod->canTransmitMessage()) {
                $worked = $mod->transmitMessage($subject, $message, $force);
                if ($worked) {
                    $success += 1;
                    $modname[] = get_class($mod);
                }
                $this->log("Message " . ($worked ? '' : 'not ') . "sent to $user via " . get_class($mod),
                    self::LOGGING_AUDITPLUS);
            }
        }
        return array($modname, $success == 0 ? false : ($success == count($module) ? true : $success));
    }

    /**
     * Transmits a One-Time Password (OTP) using configured modules.
     * If $module is set to a specific instance, that instance will be used to
     * send the OTP. If not supplied or null, then all configured modules will
     * be used to send the OTP. $module can also be an array of selected
     * modules.
     * If $force is true, then will try to send the message even if the module
     * has not been validated.
     * @return mixed - true if successfull to all attempted tramsmission
     *     modules, false if all failed, and a number of how many successes
     *     if only some modules failed.
     */
    private function _send_otp($module = null, $force = false)
    {
        $this->log("_send_otp: start", self::LOGGING_DEBUG);
        // Generate the OTP code.
        $characters = '0123456789';
        $otp = '';
        for ($index = 0; $index < $this->getConf('otplength'); ++$index) {
            $otp .= $characters[rand(0, strlen($characters) - 1)];
        }
        // Create the subject.
        $subject = $this->getConf('otpsubject');
        // Create the message.
        $message = str_replace('$otp', $otp, $this->getConf('otpcontent'));
        // Attempt to deliver the message.
        list($modname, $result) = $this->_send_message($subject, $message, $module, $force);
        // If partially successful, store the OTP code and the timestamp the OTP expires at.
        if ($result) {
            $otpData = array($otp, time() + $this->getConf('sentexpiry') * 60, $modname);
            if (!$this->attribute->set("twofactor", "otp", $otpData)) {
                msg("Unable to record OTP for later use.", -1);
            }
        }
        return $result;
    }

    /**
     * Returns the OTP code sent to the user, if it has not expired.
     * @return mixed - false if there is no unexpired OTP, otherwise
     *     array of the OTP and the modules that successfully sent it.
     */
    public function get_otp_code()
    {
        $this->log("get_otp_code: start", self::LOGGING_DEBUG);
        $otpQuery = $this->attribute->get("twofactor", "otp", $success);
        if (!$success) {
            return false;
        }
        list($otp, $expiry, $modname) = $otpQuery;
        if (time() > $expiry) {
            $this->attribute->del("twofactor", "otp");
            return false;
        }
        return array($otp, $modname);
    }

    private function _setHelperVariables($user = null)
    {
        $this->log("_setHelperVariables: start", self::LOGGING_DEBUGPLUS);
        $tokenMods = array();
        $otpMods = array();
        $state = $this->attribute->get("twofactor", "state");
        $optinout = $this->getConf("optinout");
        $enabled = $optinout == 'mandatory' || ($state == '' ? $optinout == 'optin' : $state == 'in');
        $this->log("_setHelperVariables: " . print_r(array($optinout, $state, $enabled), true), self::LOGGING_DEBUG);
        // Skip if not enabled for user
        if ($enabled) {
            // List all working token modules (GA, RSA, etc.).
            foreach ($this->modules as $name => $mod) {
                if ($mod->canAuthLogin() && $mod->canUse($user)) {
                    $this->log('Can use ' . get_class($mod) . ' for tokens', self::LOGGING_DEBUG);
                    $tokenMods[$mod->getLang("name")] = $mod;
                } else {
                    $this->log('Can NOT use ' . get_class($mod) . ' for tokens', self::LOGGING_DEBUG);
                }
            }
            // List all working OTP modules (SMS, Twilio, etc.).
            foreach ($this->modules as $name => $mod) {
                if (!$mod->canAuthLogin() && $mod->canUse($user)) {
                    $this->log('Can use ' . get_class($mod) . ' for otp', self::LOGGING_DEBUG);
                    $otpMods[$mod->getLang("name")] = $mod;
                } else {
                    $this->log('Can NOT use ' . get_class($mod) . ' for otp', self::LOGGING_DEBUG);
                }
            }
        }
        $this->tokenMods = $tokenMods;
        $this->otpMods = $otpMods;
    }

    const LOGGING_AUDIT = 1;     // Audit records 2FA login and logout activity.
    const LOGGING_AUDITPLUS = 2; // Audit+ also records sending of notifications.
    const LOGGING_DEBUG = 3;     // Debug provides detailed workflow data.
    const LOGGING_DEBUGPLUS = 4; // Debug+ also includes variables passed to and from functions.

    public function log($message, $level = 1)
    {
        // If the log level requested is below audit or greater than what is permitted in the configuration, then exit.
        if ($level < self::LOGGING_AUDIT || $level > $this->getConf('logging_level')) {
            return;
        }
        global $conf;
        // Always purge line containing "[pass]".
        $message = implode("\n", array_filter(explode("\n", $message), function ($x) {
            return !strstr($x, '[pass]');
        }));
        // If DEBUGPLUS, then append the trace log.
        if ($level == self::LOGGING_DEBUGPLUS) {
            $e = new Exception();
            $message .= "\n" . print_r(str_replace(DOKU_REL, '', $e->getTraceAsString()), true);
        }
        $logfile = $this->getConf('logging_path');
        $logfile = substr($logfile, 0, 1) == '/' ? $logfile : DOKU_INC . $conf['savedir'] . '/' . $logfile;
        io_lock($logfile);
        #open for append logfile
        $handle = @fopen($logfile, 'at');
        if ($handle) {
            $date = date(DATE_RFC2822);
            $IP = $_SERVER["REMOTE_ADDR"];
            $id = session_id();
            fwrite($handle, "$date,$id,$IP,$level,\"$message\"\n");
            fclose($handle);
        }
        #write "date level message"
        io_unlock($logfile);
    }

    // endregion
}