<?php /** * Session management class * * http://www.developpez.net/forums/d51943/php/langage/sessions/ * http://sebsauvage.net/wiki/doku.php?id=php:session * http://sebsauvage.net/wiki/doku.php?id=php:shaarli * * Features: * - Everything is stored on server-side (we do not trust client-side data, * such as cookie expiration) * - IP addresses are checked on each access to prevent session cookie hijacking * (such as Firesheep) * - Session expires on user inactivity (Session expiration date is * automatically updated everytime the user accesses a page.) * - A unique secret key is generated on server-side for this session * (and never sent over the wire) which can be used to sign forms (HMAC) * (See $_SESSION['uid']) * - Token management to prevent XSRF attacks * - Brute force protection with ban management * * TODOs * - Replace globals with variables in Session class * * How to use: * - http://tontof.net/kriss/php5/session */ class Session { // Personnalize PHP session name public static $sessionName = ''; // If the user does not access any page within this time, // his/her session is considered expired (3600 sec. = 1 hour) public static $inactivityTimeout = 3600; // If you get disconnected often or if your IP address changes often. // Let you disable session cookie hijacking protection public static $disableSessionProtection = false; // Ban IP after this many failures. public static $banAfter = 4; // Ban duration for IP address after login failures (in seconds). // (1800 sec. = 30 minutes) public static $banDuration = 1800; // File storage for failures and bans. If empty, no ban management. public static $banFile = ''; /** * Initialize session */ public static function init() { // Force cookie path (but do not change lifetime) $cookie = session_get_cookie_params(); // Default cookie expiration and path. $cookiedir = ''; if (dirname($_SERVER['SCRIPT_NAME'])!='/') { $cookiedir = dirname($_SERVER["SCRIPT_NAME"]).'/'; } $ssl = false; if (isset($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] == "on") { $ssl = true; } session_set_cookie_params($cookie['lifetime'], $cookiedir, $_SERVER['HTTP_HOST'], $ssl); // Use cookies to store session. ini_set('session.use_cookies', 1); // Force cookies for session (phpsessionID forbidden in URL) ini_set('session.use_only_cookies', 1); if (!session_id()) { // Prevent php to use sessionID in URL if cookies are disabled. ini_set('session.use_trans_sid', false); if (!empty(self::$sessionName)) { session_name(self::$sessionName); } session_start(); } } /** * Returns the IP address * (Used to prevent session cookie hijacking.) * * @return string IP addresses */ private static function _allIPs() { $ip = $_SERVER["REMOTE_ADDR"]; $ip.= isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? '_'.$_SERVER['HTTP_X_FORWARDED_FOR'] : ''; $ip.= isset($_SERVER['HTTP_CLIENT_IP']) ? '_'.$_SERVER['HTTP_CLIENT_IP'] : ''; return $ip; } /** * Check that user/password is correct and then init some SESSION variables. * * @param string $login Login reference * @param string $password Password reference * @param string $loginTest Login to compare with login reference * @param string $passwordTest Password to compare with password reference * @param array $pValues Array of variables to store in SESSION * * @return true|false True if login and password are correct, false * otherwise */ public static function login ( $login, $password, $loginTest, $passwordTest, $pValues = array()) { self::banInit(); if (self::banCanLogin()) { if ($login === $loginTest && $password === $passwordTest) { self::banLoginOk(); // Generate unique random number to sign forms (HMAC) $_SESSION['uid'] = sha1(uniqid('', true).'_'.mt_rand()); $_SESSION['ip'] = self::_allIPs(); $_SESSION['username'] = $login; // Set session expiration. $_SESSION['expires_on'] = time() + self::$inactivityTimeout; foreach ($pValues as $key => $value) { $_SESSION[$key] = $value; } return true; } self::banLoginFailed(); } return false; } /** * Unset SESSION variable to force logout */ public static function logout() { unset($_SESSION['uid'],$_SESSION['ip'],$_SESSION['expires_on'],$_SESSION['tokens'], $_SESSION['login'], $_SESSION['pass'], $_SESSION['poche_user']); } /** * Make sure user is logged in. * * @return true|false True if user is logged in, false otherwise */ public static function isLogged() { if (!isset ($_SESSION['uid']) || (self::$disableSessionProtection === false && $_SESSION['ip'] !== self::_allIPs()) || time() >= $_SESSION['expires_on']) { self::logout(); return false; } // User accessed a page : Update his/her session expiration date. $_SESSION['expires_on'] = time() + self::$inactivityTimeout; if (!empty($_SESSION['longlastingsession'])) { $_SESSION['expires_on'] += $_SESSION['longlastingsession']; } return true; } /** * Create a token, store it in SESSION and return it * * @param string $salt to prevent birthday attack * * @return string Token created */ public static function getToken($salt = '') { if (!isset($_SESSION['tokens'])) { $_SESSION['tokens']=array(); } // We generate a random string and store it on the server side. $rnd = sha1(uniqid('', true).'_'.mt_rand().$salt); $_SESSION['tokens'][$rnd]=1; return $rnd; } /** * Tells if a token is ok. Using this function will destroy the token. * * @param string $token Token to test * * @return true|false True if token is correct, false otherwise */ public static function isToken($token) { if (isset($_SESSION['tokens'][$token])) { unset($_SESSION['tokens'][$token]); // Token is used: destroy it. return true; // Token is ok. } return false; // Wrong token, or already used. } /** * Signal a failed login. Will ban the IP if too many failures: */ public static function banLoginFailed() { if (self::$banFile !== '') { $ip = $_SERVER["REMOTE_ADDR"]; $gb = $GLOBALS['IPBANS']; if (!isset($gb['FAILURES'][$ip])) { $gb['FAILURES'][$ip] = 0; } $gb['FAILURES'][$ip]++; if ($gb['FAILURES'][$ip] > (self::$banAfter - 1)) { $gb['BANS'][$ip]= time() + self::$banDuration; } $GLOBALS['IPBANS'] = $gb; file_put_contents(self::$banFile, "<?php\n\$GLOBALS['IPBANS']=".var_export($gb, true).";\n?>"); } } /** * Signals a successful login. Resets failed login counter. */ public static function banLoginOk() { if (self::$banFile !== '') { $ip = $_SERVER["REMOTE_ADDR"]; $gb = $GLOBALS['IPBANS']; unset($gb['FAILURES'][$ip]); unset($gb['BANS'][$ip]); $GLOBALS['IPBANS'] = $gb; file_put_contents(self::$banFile, "<?php\n\$GLOBALS['IPBANS']=".var_export($gb, true).";\n?>"); } } /** * Ban init */ public static function banInit() { if (self::$banFile !== '') { if (!is_file(self::$banFile)) { file_put_contents(self::$banFile, "<?php\n\$GLOBALS['IPBANS']=".var_export(array('FAILURES'=>array(), 'BANS'=>array()), true).";\n?>"); } include self::$banFile; } } /** * Checks if the user CAN login. If 'true', the user can try to login. * * @return boolean true if user is banned, false otherwise */ public static function banCanLogin() { if (self::$banFile !== '') { $ip = $_SERVER["REMOTE_ADDR"]; $gb = $GLOBALS['IPBANS']; if (isset($gb['BANS'][$ip])) { // User is banned. Check if the ban has expired: if ($gb['BANS'][$ip] <= time()) { // Ban expired, user can try to login again. unset($gb['FAILURES'][$ip]); unset($gb['BANS'][$ip]); file_put_contents(self::$banFile, "<?php\n\$GLOBALS['IPBANS']=".var_export($gb, true).";\n?>"); return true; // Ban has expired, user can login. } return false; // User is banned. } } return true; // User is not banned. } }