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<?php

/**
 * This file is concerned pretty entirely, as you see from its name, with
 * logging in and out members, and the validation of that.
 *
 * Simple Machines Forum (SMF)
 *
 * @package SMF
 * @author Simple Machines http://www.simplemachines.org
 * @copyright 2019 Simple Machines and individual contributors
 * @license http://www.simplemachines.org/about/smf/license.php BSD
 *
 * @version 2.1 RC1
 */

if (!defined('SMF'))
    die('No direct access...');

/**
 * Ask them for their login information. (shows a page for the user to type
 *  in their username and password.)
 *  It caches the referring URL in $_SESSION['login_url'].
 *  It is accessed from ?action=login.
 *
 * uses Login template and language file with the login sub-template.
 */
function Login()
{
    global $txt, $context, $scripturl, $user_info;

    // You are already logged in, go take a tour of the boards
    if (!empty($user_info['id']))
        redirectexit();

    // We need to load the Login template/language file.
    loadLanguage('Login');
    loadTemplate('Login');

    $context['sub_template'] = 'login';

    if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest')
    {
        $context['from_ajax'] = true;
        $context['template_layers'] = array();
    }

    // Get the template ready.... not really much else to do.
    $context['page_title'] = $txt['login'];
    $context['default_username'] = &$_REQUEST['u'];
    $context['default_password'] = '';
    $context['never_expire'] = false;

    // Add the login chain to the link tree.
    $context['linktree'][] = array(
        'url' => $scripturl . '?action=login',
        'name' => $txt['login'],
    );

    // Set the login URL - will be used when the login process is done (but careful not to send us to an attachment).
    if (isset($_SESSION['old_url']) && strpos($_SESSION['old_url'], 'dlattach') === false && preg_match('~(board|topic)[=,]~', $_SESSION['old_url']) != 0)
        $_SESSION['login_url'] = $_SESSION['old_url'];
    elseif (isset($_SESSION['login_url']) && strpos($_SESSION['login_url'], 'dlattach') !== false)
        unset($_SESSION['login_url']);

    // Create a one time token.
    createToken('login');
}

/**
 * Actually logs you in.
 * What it does:
 * - checks credentials and checks that login was successful.
 * - it employs protection against a specific IP or user trying to brute force
 *  a login to an account.
 * - upgrades password encryption on login, if necessary.
 * - after successful login, redirects you to $_SESSION['login_url'].
 * - accessed from ?action=login2, by forms.
 * On error, uses the same templates Login() uses.
 */
function Login2()
{
    global $txt, $scripturl, $user_info, $user_settings, $smcFunc;
    global $cookiename, $modSettings, $context, $sourcedir, $maintenance;

    // Check to ensure we're forcing SSL for authentication
    if (!empty($modSettings['force_ssl']) && empty($maintenance) && !httpsOn())
        fatal_lang_error('login_ssl_required', false);

    // Load cookie authentication stuff.
    require_once($sourcedir . '/Subs-Auth.php');

    if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest')
    {
        $context['from_ajax'] = true;
        $context['template_layers'] = array();
    }

    if (isset($_GET['sa']) && $_GET['sa'] == 'salt' && !$user_info['is_guest'])
    {
        // First check for 2.1 json-format cookie in $_COOKIE
        if (isset($_COOKIE[$cookiename]) && preg_match('~^{"0":\d+,"1":"[0-9a-f]*","2":\d+~', $_COOKIE[$cookiename]) === 1)
            list (,, $timeout) = $smcFunc['json_decode']($_COOKIE[$cookiename], true);

        // Try checking for 2.1 json-format cookie in $_SESSION
        elseif (isset($_SESSION['login_' . $cookiename]) && preg_match('~^{"0":\d+,"1":"[0-9a-f]*","2":\d+~', $_SESSION['login_' . $cookiename]) === 1)
            list (,, $timeout) = $smcFunc['json_decode']($_SESSION['login_' . $cookiename]);

        // Next, try checking for 2.0 serialized string cookie in $_COOKIE
        elseif (isset($_COOKIE[$cookiename]) && preg_match('~^a:[34]:\{i:0;i:\d+;i:1;s:(0|128):"([a-fA-F0-9]{128})?";i:2;[id]:\d+;~', $_COOKIE[$cookiename]) === 1)
            list (,, $timeout) = safe_unserialize($_COOKIE[$cookiename]);

        // Last, see if you need to fall back on checking for 2.0 serialized string cookie in $_SESSION
        elseif (isset($_SESSION['login_' . $cookiename]) && preg_match('~^a:[34]:\{i:0;i:\d+;i:1;s:(0|128):"([a-fA-F0-9]{128})?";i:2;[id]:\d+;~', $_SESSION['login_' . $cookiename]) === 1)
            list (,, $timeout) = safe_unserialize($_SESSION['login_' . $cookiename]);

        else
            trigger_error('Login2(): Cannot be logged in without a session or cookie', E_USER_ERROR);

        $user_settings['password_salt'] = substr(md5($smcFunc['random_int']()), 0, 4);
        updateMemberData($user_info['id'], array('password_salt' => $user_settings['password_salt']));

        // Preserve the 2FA cookie?
        if (!empty($modSettings['tfa_mode']) && !empty($_COOKIE[$cookiename . '_tfa']))
        {
            list (,, $exp) = $smcFunc['json_decode']($_COOKIE[$cookiename . '_tfa'], true);
            setTFACookie((int) $exp - time(), $user_info['password_salt'], hash_salt($user_settings['tfa_backup'], $user_settings['password_salt']));
        }

        setLoginCookie((int) $timeout - time(), $user_info['id'], hash_salt($user_settings['passwd'], $user_settings['password_salt']));

        redirectexit('action=login2;sa=check;member=' . $user_info['id'], $context['server']['needs_login_fix']);
    }
    // Double check the cookie...
    elseif (isset($_GET['sa']) && $_GET['sa'] == 'check')
    {
        // Strike!  You're outta there!
        if ($_GET['member'] != $user_info['id'])
            fatal_lang_error('login_cookie_error', false);

        $user_info['can_mod'] = allowedTo('access_mod_center') || (!$user_info['is_guest'] && ($user_info['mod_cache']['gq'] != '0=1' || $user_info['mod_cache']['bq'] != '0=1' || ($modSettings['postmod_active'] && !empty($user_info['mod_cache']['ap']))));

        // Some whitelisting for login_url...
        if (empty($_SESSION['login_url']))
            redirectexit(empty($user_settings['tfa_secret']) ? '' : 'action=logintfa');
        elseif (!empty($_SESSION['login_url']) && (strpos($_SESSION['login_url'], 'http://') === false && strpos($_SESSION['login_url'], 'https://') === false))
        {
            unset ($_SESSION['login_url']);
            redirectexit(empty($user_settings['tfa_secret']) ? '' : 'action=logintfa');
        }
        elseif (!empty($user_settings['tfa_secret']))
        {
            redirectexit('action=logintfa');
        }
        else
        {
            // Best not to clutter the session data too much...
            $temp = $_SESSION['login_url'];
            unset($_SESSION['login_url']);

            redirectexit($temp);
        }
    }

    // Beyond this point you are assumed to be a guest trying to login.
    if (!$user_info['is_guest'])
        redirectexit();

    // Are you guessing with a script?
    checkSession();
    validateToken('login');
    spamProtection('login');

    // Set the login_url if it's not already set (but careful not to send us to an attachment).
    if ((empty($_SESSION['login_url']) && isset($_SESSION['old_url']) && strpos($_SESSION['old_url'], 'dlattach') === false && preg_match('~(board|topic)[=,]~', $_SESSION['old_url']) != 0) || (isset($_GET['quicklogin']) && isset($_SESSION['old_url']) && strpos($_SESSION['old_url'], 'login') === false))
        $_SESSION['login_url'] = $_SESSION['old_url'];

    // Been guessing a lot, haven't we?
    if (isset($_SESSION['failed_login']) && $_SESSION['failed_login'] >= $modSettings['failed_login_threshold'] * 3)
        fatal_lang_error('login_threshold_fail', 'login');

    // Set up the cookie length.  (if it's invalid, just fall through and use the default.)
    if (isset($_POST['cookieneverexp']) || (!empty($_POST['cookielength']) && $_POST['cookielength'] == -1))
        $modSettings['cookieTime'] = 3153600;
    elseif (!empty($_POST['cookielength']) && ($_POST['cookielength'] >= 1 && $_POST['cookielength'] <= 3153600))
        $modSettings['cookieTime'] = (int) $_POST['cookielength'];

    loadLanguage('Login');
    // Load the template stuff.
    loadTemplate('Login');
    $context['sub_template'] = 'login';

    // Set up the default/fallback stuff.
    $context['default_username'] = isset($_POST['user']) ? preg_replace('~&amp;#(\\d{1,7}|x[0-9a-fA-F]{1,6});~', '&#\\1;', $smcFunc['htmlspecialchars']($_POST['user'])) : '';
    $context['default_password'] = '';
    $context['never_expire'] = $modSettings['cookieTime'] <= 525600;
    $context['login_errors'] = array($txt['error_occured']);
    $context['page_title'] = $txt['login'];

    // Add the login chain to the link tree.
    $context['linktree'][] = array(
        'url' => $scripturl . '?action=login',
        'name' => $txt['login'],
    );

    // You forgot to type your username, dummy!
    if (!isset($_POST['user']) || $_POST['user'] == '')
    {
        $context['login_errors'] = array($txt['need_username']);
        return;
    }

    // Hmm... maybe 'admin' will login with no password. Uhh... NO!
    if (!isset($_POST['passwrd']) || $_POST['passwrd'] == '')
    {
        $context['login_errors'] = array($txt['no_password']);
        return;
    }

    // No funky symbols either.
    if (preg_match('~[<>&"\'=\\\]~', preg_replace('~(&#(\\d{1,7}|x[0-9a-fA-F]{1,6});)~', '', $_POST['user'])) != 0)
    {
        $context['login_errors'] = array($txt['error_invalid_characters_username']);
        return;
    }

    // And if it's too long, trim it back.
    if ($smcFunc['strlen']($_POST['user']) > 80)
    {
        $_POST['user'] = $smcFunc['substr']($_POST['user'], 0, 79);
        $context['default_username'] = preg_replace('~&amp;#(\\d{1,7}|x[0-9a-fA-F]{1,6});~', '&#\\1;', $smcFunc['htmlspecialchars']($_POST['user']));
    }

    // Are we using any sort of integration to validate the login?
    if (in_array('retry', call_integration_hook('integrate_validate_login', array($_POST['user'], isset($_POST['passwrd']) ? $_POST['passwrd'] : null, $modSettings['cookieTime'])), true))
    {
        $context['login_errors'] = array($txt['incorrect_password']);
        return;
    }

    // Load the data up!
    $request = $smcFunc['db_query']('', '
        SELECT passwd, id_member, id_group, lngfile, is_activated, email_address, additional_groups, member_name, password_salt,
            passwd_flood, tfa_secret
        FROM {db_prefix}members
        WHERE ' . ($smcFunc['db_case_sensitive'] ? 'LOWER(member_name) = LOWER({string:user_name})' : 'member_name = {string:user_name}') . '
        LIMIT 1',
        array(
            'user_name' => $smcFunc['db_case_sensitive'] ? strtolower($_POST['user']) : $_POST['user'],
        )
    );
    // Probably mistyped or their email, try it as an email address. (member_name first, though!)
    if ($smcFunc['db_num_rows']($request) == 0 && strpos($_POST['user'], '@') !== false)
    {
        $smcFunc['db_free_result']($request);

        $request = $smcFunc['db_query']('', '
            SELECT passwd, id_member, id_group, lngfile, is_activated, email_address, additional_groups, member_name, password_salt,
                passwd_flood, tfa_secret
            FROM {db_prefix}members
            WHERE email_address = {string:user_name}
            LIMIT 1',
            array(
                'user_name' => $_POST['user'],
            )
        );
    }

    // Let them try again, it didn't match anything...
    if ($smcFunc['db_num_rows']($request) == 0)
    {
        $context['login_errors'] = array($txt['username_no_exist']);
        return;
    }

    $user_settings = $smcFunc['db_fetch_assoc']($request);
    $smcFunc['db_free_result']($request);

    // Bad password!  Thought you could fool the database?!
    if (!hash_verify_password($user_settings['member_name'], un_htmlspecialchars($_POST['passwrd']), $user_settings['passwd']))
    {
        // Let's be cautious, no hacking please. thanx.
        validatePasswordFlood($user_settings['id_member'], $user_settings['member_name'], $user_settings['passwd_flood']);

        // Maybe we were too hasty... let's try some other authentication methods.
        $other_passwords = array();

        // None of the below cases will be used most of the time (because the salt is normally set.)
        if (!empty($modSettings['enable_password_conversion']) && $user_settings['password_salt'] == '')
        {
            // YaBB SE, Discus, MD5 (used a lot), SHA-1 (used some), SMF 1.0.x, IkonBoard, and none at all.
            $other_passwords[] = crypt($_POST['passwrd'], substr($_POST['passwrd'], 0, 2));
            $other_passwords[] = crypt($_POST['passwrd'], substr($user_settings['passwd'], 0, 2));
            $other_passwords[] = md5($_POST['passwrd']);
            $other_passwords[] = sha1($_POST['passwrd']);
            $other_passwords[] = md5_hmac($_POST['passwrd'], strtolower($user_settings['member_name']));
            $other_passwords[] = md5($_POST['passwrd'] . strtolower($user_settings['member_name']));
            $other_passwords[] = md5(md5($_POST['passwrd']));
            $other_passwords[] = $_POST['passwrd'];

            // This one is a strange one... MyPHP, crypt() on the MD5 hash.
            $other_passwords[] = crypt(md5($_POST['passwrd']), md5($_POST['passwrd']));

            // Snitz style - SHA-256.  Technically, this is a downgrade, but most PHP configurations don't support sha256 anyway.
            if (strlen($user_settings['passwd']) == 64 && function_exists('mhash') && defined('MHASH_SHA256'))
                $other_passwords[] = bin2hex(mhash(MHASH_SHA256, $_POST['passwrd']));

            // phpBB3 users new hashing.  We now support it as well ;).
            $other_passwords[] = phpBB3_password_check($_POST['passwrd'], $user_settings['passwd']);

            // APBoard 2 Login Method.
            $other_passwords[] = md5(crypt($_POST['passwrd'], 'CRYPT_MD5'));
        }
        // The hash should be 40 if it's SHA-1, so we're safe with more here too.
        elseif (!empty($modSettings['enable_password_conversion']) && strlen($user_settings['passwd']) == 32)
        {
            // vBulletin 3 style hashing?  Let's welcome them with open arms \o/.
            $other_passwords[] = md5(md5($_POST['passwrd']) . stripslashes($user_settings['password_salt']));

            // Hmm.. p'raps it's Invision 2 style?
            $other_passwords[] = md5(md5($user_settings['password_salt']) . md5($_POST['passwrd']));

            // Some common md5 ones.
            $other_passwords[] = md5($user_settings['password_salt'] . $_POST['passwrd']);
            $other_passwords[] = md5($_POST['passwrd'] . $user_settings['password_salt']);
        }
        elseif (strlen($user_settings['passwd']) == 40)
        {
            // Maybe they are using a hash from before the password fix.
            // This is also valid for SMF 1.1 to 2.0 style of hashing, changed to bcrypt in SMF 2.1
            $other_passwords[] = sha1(strtolower($user_settings['member_name']) . un_htmlspecialchars($_POST['passwrd']));

            // BurningBoard3 style of hashing.
            if (!empty($modSettings['enable_password_conversion']))
                $other_passwords[] = sha1($user_settings['password_salt'] . sha1($user_settings['password_salt'] . sha1($_POST['passwrd'])));

            // Perhaps we converted to UTF-8 and have a valid password being hashed differently.
            if ($context['character_set'] == 'UTF-8' && !empty($modSettings['previousCharacterSet']) && $modSettings['previousCharacterSet'] != 'utf8')
            {
                // Try iconv first, for no particular reason.
                if (function_exists('iconv'))
                    $other_passwords['iconv'] = sha1(strtolower(iconv('UTF-8', $modSettings['previousCharacterSet'], $user_settings['member_name'])) . un_htmlspecialchars(iconv('UTF-8', $modSettings['previousCharacterSet'], $_POST['passwrd'])));

                // Say it aint so, iconv failed!
                if (empty($other_passwords['iconv']) && function_exists('mb_convert_encoding'))
                    $other_passwords[] = sha1(strtolower(mb_convert_encoding($user_settings['member_name'], 'UTF-8', $modSettings['previousCharacterSet'])) . un_htmlspecialchars(mb_convert_encoding($_POST['passwrd'], 'UTF-8', $modSettings['previousCharacterSet'])));
            }
        }

        // SMF's sha1 function can give a funny result on Linux (Not our fault!). If we've now got the real one let the old one be valid!
        if (stripos(PHP_OS, 'win') !== 0 && strlen($user_settings['passwd']) < hash_length())
        {
            require_once($sourcedir . '/Subs-Compat.php');
            $other_passwords[] = sha1_smf(strtolower($user_settings['member_name']) . un_htmlspecialchars($_POST['passwrd']));
        }

        // Allows mods to easily extend the $other_passwords array
        call_integration_hook('integrate_other_passwords', array(&$other_passwords));

        // Whichever encryption it was using, let's make it use SMF's now ;).
        if (in_array($user_settings['passwd'], $other_passwords))
        {
            $user_settings['passwd'] = hash_password($user_settings['member_name'], un_htmlspecialchars($_POST['passwrd']));
            $user_settings['password_salt'] = substr(md5($smcFunc['random_int']()), 0, 4);

            // Update the password and set up the hash.
            updateMemberData($user_settings['id_member'], array('passwd' => $user_settings['passwd'], 'password_salt' => $user_settings['password_salt'], 'passwd_flood' => ''));
        }
        // Okay, they for sure didn't enter the password!
        else
        {
            // They've messed up again - keep a count to see if they need a hand.
            $_SESSION['failed_login'] = isset($_SESSION['failed_login']) ? ($_SESSION['failed_login'] + 1) : 1;

            // Hmm... don't remember it, do you?  Here, try the password reminder ;).
            if ($_SESSION['failed_login'] >= $modSettings['failed_login_threshold'])
                redirectexit('action=reminder');
            // We'll give you another chance...
            else
            {
                // Log an error so we know that it didn't go well in the error log.
                log_error($txt['incorrect_password'] . ' - <span class="remove">' . $user_settings['member_name'] . '</span>', 'user');

                $context['login_errors'] = array($txt['incorrect_password']);
                return;
            }
        }
    }
    elseif (!empty($user_settings['passwd_flood']))
    {
        // Let's be sure they weren't a little hacker.
        validatePasswordFlood($user_settings['id_member'], $user_settings['member_name'], $user_settings['passwd_flood'], true);

        // If we got here then we can reset the flood counter.
        updateMemberData($user_settings['id_member'], array('passwd_flood' => ''));
    }

    // Correct password, but they've got no salt; fix it!
    if ($user_settings['password_salt'] == '')
    {
        $user_settings['password_salt'] = substr(md5($smcFunc['random_int']()), 0, 4);
        updateMemberData($user_settings['id_member'], array('password_salt' => $user_settings['password_salt']));
    }

    // Check their activation status.
    if (!checkActivation())
        return;

    DoLogin();
}

/**
 * Allows the user to enter their Two-Factor Authentication code
 */
function LoginTFA()
{
    global $sourcedir, $txt, $context, $user_info, $modSettings, $scripturl;

    if (!$user_info['is_guest'] || empty($context['tfa_member']) || empty($modSettings['tfa_mode']))
        fatal_lang_error('no_access', false);

    loadLanguage('Profile');
    require_once($sourcedir . '/Class-TOTP.php');

    $member = $context['tfa_member'];

    // Prevent replay attacks by limiting at least 2 minutes before they can log in again via 2FA
    if (time() - $member['last_login'] < 120)
        fatal_lang_error('tfa_wait', false);

    $totp = new \TOTP\Auth($member['tfa_secret']);
    $totp->setRange(1);

    if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest')
    {
        $context['from_ajax'] = true;
        $context['template_layers'] = array();
    }

    if (!empty($_POST['tfa_code']) && empty($_POST['tfa_backup']))
    {
        // Check to ensure we're forcing SSL for authentication
        if (!empty($modSettings['force_ssl']) && empty($maintenance) && !httpsOn())
            fatal_lang_error('login_ssl_required', false);

        $code = $_POST['tfa_code'];

        if (strlen($code) == $totp->getCodeLength() && $totp->validateCode($code))
        {
            updateMemberData($member['id_member'], array('last_login' => time()));

            setTFACookie(3153600, $member['id_member'], hash_salt($member['tfa_backup'], $member['password_salt']));
            redirectexit();
        }
        else
        {
            validatePasswordFlood($member['id_member'], $member['member_name'], $member['passwd_flood'], false, true);

            $context['tfa_error'] = true;
            $context['tfa_value'] = $_POST['tfa_code'];
        }
    }
    elseif (!empty($_POST['tfa_backup']))
    {
        // Check to ensure we're forcing SSL for authentication
        if (!empty($modSettings['force_ssl']) && empty($maintenance) && !httpsOn())
            fatal_lang_error('login_ssl_required', false);

        $backup = $_POST['tfa_backup'];

        if (hash_verify_password($member['member_name'], $backup, $member['tfa_backup']))
        {
            // Get rid of their current TFA settings
            updateMemberData($member['id_member'], array(
                'tfa_secret' => '',
                'tfa_backup' => '',
                'last_login' => time(),
            ));
            setTFACookie(3153600, $member['id_member'], hash_salt($member['tfa_backup'], $member['password_salt']));
            redirectexit('action=profile;area=tfasetup;backup');
        }
        else
        {
            validatePasswordFlood($member['id_member'], $member['member_name'], $member['passwd_flood'], false, true);

            $context['tfa_backup_error'] = true;
            $context['tfa_value'] = $_POST['tfa_code'];
            $context['tfa_backup_value'] = $_POST['tfa_backup'];
        }
    }

    loadTemplate('Login');
    $context['sub_template'] = 'login_tfa';
    $context['page_title'] = $txt['login'];
    $context['tfa_url'] = $scripturl . '?action=logintfa';
}

/**
 * Check activation status of the current user.
 */
function checkActivation()
{
    global $context, $txt, $scripturl, $user_settings, $modSettings;

    if (!isset($context['login_errors']))
        $context['login_errors'] = array();

    // What is the true activation status of this account?
    $activation_status = $user_settings['is_activated'] > 10 ? $user_settings['is_activated'] - 10 : $user_settings['is_activated'];

    // Check if the account is activated - COPPA first...
    if ($activation_status == 5)
    {
        $context['login_errors'][] = $txt['coppa_no_concent'] . ' <a href="' . $scripturl . '?action=coppa;member=' . $user_settings['id_member'] . '">' . $txt['coppa_need_more_details'] . '</a>';
        return false;
    }
    // Awaiting approval still?
    elseif ($activation_status == 3)
        fatal_lang_error('still_awaiting_approval', 'user');
    // Awaiting deletion, changed their mind?
    elseif ($activation_status == 4)
    {
        if (isset($_REQUEST['undelete']))
        {
            updateMemberData($user_settings['id_member'], array('is_activated' => 1));
            updateSettings(array('unapprovedMembers' => ($modSettings['unapprovedMembers'] > 0 ? $modSettings['unapprovedMembers'] - 1 : 0)));
        }
        else
        {
            $context['disable_login_hashing'] = true;
            $context['login_errors'][] = $txt['awaiting_delete_account'];
            $context['login_show_undelete'] = true;
            return false;
        }
    }
    // Standard activation?
    elseif ($activation_status != 1)
    {
        log_error($txt['activate_not_completed1'] . ' - <span class="remove">' . $user_settings['member_name'] . '</span>', false);

        $context['login_errors'][] = $txt['activate_not_completed1'] . ' <a href="' . $scripturl . '?action=activate;sa=resend;u=' . $user_settings['id_member'] . '">' . $txt['activate_not_completed2'] . '</a>';
        return false;
    }
    return true;
}

/**
 * Perform the logging in. (set cookie, call hooks, etc)
 */
function DoLogin()
{
    global $user_info, $user_settings, $smcFunc;
    global $maintenance, $modSettings, $context, $sourcedir;

    // Load cookie authentication stuff.
    require_once($sourcedir . '/Subs-Auth.php');

    // Call login integration functions.
    call_integration_hook('integrate_login', array($user_settings['member_name'], null, $modSettings['cookieTime']));

    // Get ready to set the cookie...
    $user_info['id'] = $user_settings['id_member'];

    // Bam!  Cookie set.  A session too, just in case.
    setLoginCookie(60 * $modSettings['cookieTime'], $user_settings['id_member'], hash_salt($user_settings['passwd'], $user_settings['password_salt']));

    // Reset the login threshold.
    if (isset($_SESSION['failed_login']))
        unset($_SESSION['failed_login']);

    $user_info['is_guest'] = false;
    $user_settings['additional_groups'] = explode(',', $user_settings['additional_groups']);
    $user_info['is_admin'] = $user_settings['id_group'] == 1 || in_array(1, $user_settings['additional_groups']);

    // Are you banned?
    is_not_banned(true);

    // Don't stick the language or theme after this point.
    unset($_SESSION['language'], $_SESSION['id_theme']);

    // First login?
    $request = $smcFunc['db_query']('', '
        SELECT last_login
        FROM {db_prefix}members
        WHERE id_member = {int:id_member}
            AND last_login = 0',
        array(
            'id_member' => $user_info['id'],
        )
    );
    if ($smcFunc['db_num_rows']($request) == 1)
        $_SESSION['first_login'] = true;
    else
        unset($_SESSION['first_login']);
    $smcFunc['db_free_result']($request);

    // You've logged in, haven't you?
    $update = array('member_ip' => $user_info['ip'], 'member_ip2' => $_SERVER['BAN_CHECK_IP']);
    if (empty($user_settings['tfa_secret']))
        $update['last_login'] = time();
    updateMemberData($user_info['id'], $update);

    // Get rid of the online entry for that old guest....
    $smcFunc['db_query']('', '
        DELETE FROM {db_prefix}log_online
        WHERE session = {string:session}',
        array(
            'session' => 'ip' . $user_info['ip'],
        )
    );
    $_SESSION['log_time'] = 0;

    // Log this entry, only if we have it enabled.
    if (!empty($modSettings['loginHistoryDays']))
        $smcFunc['db_insert']('insert',
            '{db_prefix}member_logins',
            array(
                'id_member' => 'int', 'time' => 'int', 'ip' => 'inet', 'ip2' => 'inet',
            ),
            array(
                $user_info['id'], time(), $user_info['ip'], $user_info['ip2']
            ),
            array(
                'id_member', 'time'
            )
        );

    // Just log you back out if it's in maintenance mode and you AREN'T an admin.
    if (empty($maintenance) || allowedTo('admin_forum'))
        redirectexit('action=login2;sa=check;member=' . $user_info['id'], $context['server']['needs_login_fix']);
    else
        redirectexit('action=logout;' . $context['session_var'] . '=' . $context['session_id'], $context['server']['needs_login_fix']);
}

/**
 * Logs the current user out of their account.
 * It requires that the session hash is sent as well, to prevent automatic logouts by images or javascript.
 * It redirects back to $_SESSION['logout_url'], if it exists.
 * It is accessed via ?action=logout;session_var=...
 *
 * @param bool $internal If true, it doesn't check the session
 * @param bool $redirect Whether or not to redirect the user after they log out
 */
function Logout($internal = false, $redirect = true)
{
    global $sourcedir, $user_info, $user_settings, $context, $smcFunc, $cookiename, $modSettings;

    // Make sure they aren't being auto-logged out.
    if (!$internal)
        checkSession('get');

    require_once($sourcedir . '/Subs-Auth.php');

    if (isset($_SESSION['pack_ftp']))
        $_SESSION['pack_ftp'] = null;

    // It won't be first login anymore.
    unset($_SESSION['first_login']);

    // Just ensure they aren't a guest!
    if (!$user_info['is_guest'])
    {
        // Pass the logout information to integrations.
        call_integration_hook('integrate_logout', array($user_settings['member_name']));

        // If you log out, you aren't online anymore :P.
        $smcFunc['db_query']('', '
            DELETE FROM {db_prefix}log_online
            WHERE id_member = {int:current_member}',
            array(
                'current_member' => $user_info['id'],
            )
        );
    }

    $_SESSION['log_time'] = 0;

    // Empty the cookie! (set it in the past, and for id_member = 0)
    setLoginCookie(-3600, 0);

    // And some other housekeeping while we're at it.
    $salt = substr(md5($smcFunc['random_int']()), 0, 4);
    if (!empty($user_info['id']))
        updateMemberData($user_info['id'], array('password_salt' => $salt));

    if (!empty($modSettings['tfa_mode']) && !empty($user_info['id']) && !empty($_COOKIE[$cookiename . '_tfa']))
    {
        list (,, $exp) = $smcFunc['json_decode']($_COOKIE[$cookiename . '_tfa'], true);
        setTFACookie((int) $exp - time(), $salt, hash_salt($user_settings['tfa_backup'], $salt));
    }

    session_destroy();

    // Off to the merry board index we go!
    if ($redirect)
    {
        if (empty($_SESSION['logout_url']))
            redirectexit('', $context['server']['needs_login_fix']);
        elseif (!empty($_SESSION['logout_url']) && (strpos($_SESSION['logout_url'], 'http://') === false && strpos($_SESSION['logout_url'], 'https://') === false))
        {
            unset ($_SESSION['logout_url']);
            redirectexit();
        }
        else
        {
            $temp = $_SESSION['logout_url'];
            unset($_SESSION['logout_url']);

            redirectexit($temp, $context['server']['needs_login_fix']);
        }
    }
}

/**
 * MD5 Encryption used for older passwords. (SMF 1.0.x/YaBB SE 1.5.x hashing)
 *
 * @param string $data The data
 * @param string $key The key
 * @return string The HMAC MD5 of data with key
 */
function md5_hmac($data, $key)
{
    $key = str_pad(strlen($key) <= 64 ? $key : pack('H*', md5($key)), 64, chr(0x00));
    return md5(($key ^ str_repeat(chr(0x5c), 64)) . pack('H*', md5(($key ^ str_repeat(chr(0x36), 64)) . $data)));
}

/**
 * Custom encryption for phpBB3 based passwords.
 *
 * @param string $passwd The raw (unhashed) password
 * @param string $passwd_hash The hashed password
 * @return string The hashed version of $passwd
 */
function phpBB3_password_check($passwd, $passwd_hash)
{
    // Too long or too short?
    if (strlen($passwd_hash) != 34)
        return;

    // Range of characters allowed.
    $range = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

    // Tests
    $strpos = strpos($range, $passwd_hash[3]);
    $count = 1 << $strpos;
    $salt = substr($passwd_hash, 4, 8);

    $hash = md5($salt . $passwd, true);
    for (; $count != 0; --$count)
        $hash = md5($hash . $passwd, true);

    $output = substr($passwd_hash, 0, 12);
    $i = 0;
    while ($i < 16)
    {
        $value = ord($hash[$i++]);
        $output .= $range[$value & 0x3f];

        if ($i < 16)
            $value |= ord($hash[$i]) << 8;

        $output .= $range[($value >> 6) & 0x3f];

        if ($i++ >= 16)
            break;

        if ($i < 16)
            $value |= ord($hash[$i]) << 16;

        $output .= $range[($value >> 12) & 0x3f];

        if ($i++ >= 16)
            break;

        $output .= $range[($value >> 18) & 0x3f];
    }

    // Return now.
    return $output;
}

/**
 * This protects against brute force attacks on a member's password.
 * Importantly, even if the password was right we DON'T TELL THEM!
 *
 * @param int $id_member The ID of the member
 * @param string $member_name The name of the member.
 * @param bool|string $password_flood_value False if we don't have a flood value, otherwise a string with a timestamp and number of tries separated by a |
 * @param bool $was_correct Whether or not the password was correct
 * @param bool $tfa Whether we're validating for two-factor authentication
 */
function validatePasswordFlood($id_member, $member_name, $password_flood_value = false, $was_correct = false, $tfa = false)
{
    global $cookiename, $sourcedir;

    // As this is only brute protection, we allow 5 attempts every 10 seconds.

    // Destroy any session or cookie data about this member, as they validated wrong.
    // Only if they're not validating for 2FA
    if (!$tfa)
    {
        require_once($sourcedir . '/Subs-Auth.php');
        setLoginCookie(-3600, 0);

        if (isset($_SESSION['login_' . $cookiename]))
            unset($_SESSION['login_' . $cookiename]);
    }

    // We need a member!
    if (!$id_member)
    {
        // Redirect back!
        redirectexit();

        // Probably not needed, but still make sure...
        fatal_lang_error('no_access', false);
    }

    // Right, have we got a flood value?
    if ($password_flood_value !== false)
        @list ($time_stamp, $number_tries) = explode('|', $password_flood_value);

    // Timestamp or number of tries invalid?
    if (empty($number_tries) || empty($time_stamp))
    {
        $number_tries = 0;
        $time_stamp = time();
    }

    // They've failed logging in already
    if (!empty($number_tries))
    {
        // Give them less chances if they failed before
        $number_tries = $time_stamp < time() - 20 ? 2 : $number_tries;

        // They are trying too fast, make them wait longer
        if ($time_stamp < time() - 10)
            $time_stamp = time();
    }

    $number_tries++;

    // Broken the law?
    if ($number_tries > 5)
        fatal_lang_error('login_threshold_brute_fail', 'login', [$member_name]);

    // Otherwise set the members data. If they correct on their first attempt then we actually clear it, otherwise we set it!
    updateMemberData($id_member, array('passwd_flood' => $was_correct && $number_tries == 1 ? '' : $time_stamp . '|' . $number_tries));

}

?>