session.php

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<?php
/* SVN FILE: $Id: session.php 8186 2009-06-03 16:22:00Z mark_story $ */
/**
 * Session class for Cake.
 *
 * Cake abstracts the handling of sessions.
 * There are several convenient methods to access session information.
 * This class is the implementation of those methods.
 * They are mostly used by the Session Component.
 *
 * PHP versions 4 and 5
 *
 * CakePHP(tm) :  Rapid Development Framework (http://www.cakephp.org)
 * Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @filesource
 * @copyright     Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 * @link          http://www.cakefoundation.org/projects/info/cakephp CakePHP(tm) Project
 * @package       cake
 * @subpackage    cake.cake.libs
 * @since         CakePHP(tm) v .0.10.0.1222
 * @version       $Revision: 8186 $
 * @modifiedby    $LastChangedBy: mark_story $
 * @lastmodified  $Date: 2009-06-03 12:22:00 -0400 (Wed, 03 Jun 2009) $
 * @license       http://www.opensource.org/licenses/mit-license.php The MIT License
 */
/**
 * Database name for cake sessions.
 *
 */
if (!class_exists('Set')) {
    require LIBS . 'set.php';
}
if (!class_exists('Security')) {
    require LIBS . 'security.php';
}
/**
 * Session class for Cake.
 *
 * Cake abstracts the handling of sessions. There are several convenient methods to access session information.
 * This class is the implementation of those methods. They are mostly used by the Session Component.
 *
 * @package       cake
 * @subpackage    cake.cake.libs
 */
class CakeSession extends Object {
/**
 * True if the Session is still valid
 *
 * @var boolean
 * @access public
 */
    var $valid = false;
/**
 * Error messages for this session
 *
 * @var array
 * @access public
 */
    var $error = false;
/**
 * User agent string
 *
 * @var string
 * @access protected
 */
    var $_userAgent = '';
/**
 * Path to where the session is active.
 *
 * @var string
 * @access public
 */
    var $path = '/';
/**
 * Error number of last occurred error
 *
 * @var integer
 * @access public
 */
    var $lastError = null;
/**
 * 'Security.level' setting, "high", "medium", or "low".
 *
 * @var string
 * @access public
 */
    var $security = null;
/**
 * Start time for this session.
 *
 * @var integer
 * @access public
 */
    var $time = false;
/**
 * Time when this session becomes invalid.
 *
 * @var integer
 * @access public
 */
    var $sessionTime = false;
/**
 * Keeps track of keys to watch for writes on
 *
 * @var array
 * @access public
 */
    var $watchKeys = array();
/**
 * Current Session id
 *
 * @var string
 * @access public
 */
    var $id = null;
/**
 * Constructor.
 *
 * @param string $base The base path for the Session
 * @param boolean $start Should session be started right now
 * @access public
 */
    function __construct($base = null, $start = true) {
        if (Configure::read('Session.save') === 'database' && !class_exists('ConnectionManager')) {
            App::import('Core', 'ConnectionManager');
        }

        if (Configure::read('Session.checkAgent') === true || Configure::read('Session.checkAgent') === null) {
            if (env('HTTP_USER_AGENT') != null) {
                $this->_userAgent = md5(env('HTTP_USER_AGENT') . Configure::read('Security.salt'));
            }
        }
        $this->time = time();

        if ($start === true) {
            if (!empty($base)) {
                $this->path = $base;
                if (strpos($base, 'index.php') !== false) {
                   $this->path = str_replace('index.php', '', $base);
                }
                if (strpos($base, '?') !== false) {
                   $this->path = str_replace('?', '', $base);
                }
            }
            $this->host = env('HTTP_HOST');

            if (strpos($this->host, ':') !== false) {
                $this->host = substr($this->host, 0, strpos($this->host, ':'));
            }
            if (!class_exists('Security')) {
                App::import('Core', 'Security');
            }
            $this->sessionTime = $this->time + (Security::inactiveMins() * Configure::read('Session.timeout'));
            $this->security = Configure::read('Security.level');
        }
        parent::__construct();
    }
/**
 * Starts the Session.
 *
 * @param string $name Variable name to check for
 * @return boolean True if variable is there
 * @access public
 */
    function start() {
        if (function_exists('session_write_close')) {
            session_write_close();
        }
        $this->__initSession();
        return $this->__startSession();
    }
/**
 * Determine if Session has been started.
 *
 * @access public
 * @return boolean True if session has been started.
 */
    function started() {
        if (isset($_SESSION)) {
            return true;
        }
        return false;
    }
/**
 * Returns true if given variable is set in session.
 *
 * @param string $name Variable name to check for
 * @return boolean True if variable is there
 * @access public
 */
    function check($name) {
        $var = $this->__validateKeys($name);
        if (empty($var)) {
            return false;
        }
        $result = Set::extract($_SESSION, $var);
        return isset($result);
    }
/**
 * Returns the Session id
 *
 * @param id $name string
 * @return string Session id
 * @access public
 */
    function id($id = null) {
        if ($id) {
            $this->id = $id;
            session_id($this->id);
        }
        if (isset($_SESSION)) {
            return session_id();
        } else {
            return $this->id;
        }
    }
/**
 * Removes a variable from session.
 *
 * @param string $name Session variable to remove
 * @return boolean Success
 * @access public
 */
    function del($name) {
        if ($this->check($name)) {
            if ($var = $this->__validateKeys($name)) {
                if (in_array($var, $this->watchKeys)) {
                    trigger_error('Deleting session key {' . $var . '}', E_USER_NOTICE);
                }
                $this->__overwrite($_SESSION, Set::remove($_SESSION, $var));
                return ($this->check($var) == false);
            }
        }
        $this->__setError(2, "$name doesn't exist");
        return false;
    }
/**
 * Used to write new data to _SESSION, since PHP doesn't like us setting the _SESSION var itself
 *
 * @param array $old Set of old variables => values
 * @param array $new New set of variable => value
 * @access private
 */
    function __overwrite(&$old, $new) {
        if (!empty($old)) {
            foreach ($old as $key => $var) {
                if (!isset($new[$key])) {
                    unset($old[$key]);
                }
            }
        }
        foreach ($new as $key => $var) {
            $old[$key] = $var;
        }
    }
/**
 * Return error description for given error number.
 *
 * @param integer $errorNumber Error to set
 * @return string Error as string
 * @access private
 */
    function __error($errorNumber) {
        if (!is_array($this->error) || !array_key_exists($errorNumber, $this->error)) {
            return false;
        } else {
            return $this->error[$errorNumber];
        }
    }
/**
 * Returns last occurred error as a string, if any.
 *
 * @return mixed Error description as a string, or false.
 * @access public
 */
    function error() {
        if ($this->lastError) {
            return $this->__error($this->lastError);
        } else {
            return false;
        }
    }
/**
 * Returns true if session is valid.
 *
 * @return boolean Success
 * @access public
 */
    function valid() {
        if ($this->read('Config')) {
            if ((Configure::read('Session.checkAgent') === false || $this->_userAgent == $this->read('Config.userAgent')) && $this->time <= $this->read('Config.time')) {
                if ($this->error === false) {
                    $this->valid = true;
                }
            } else {
                $this->valid = false;
                $this->__setError(1, 'Session Highjacking Attempted !!!');
            }
        }
        return $this->valid;
    }
/**
 * Returns given session variable, or all of them, if no parameters given.
 *
 * @param mixed $name The name of the session variable (or a path as sent to Set.extract)
 * @return mixed The value of the session variable
 * @access public
 */
    function read($name = null) {
        if (is_null($name)) {
            return $this->__returnSessionVars();
        }
        if (empty($name)) {
            return false;
        }
        $result = Set::extract($_SESSION, $name);

        if (!is_null($result)) {
            return $result;
        }
        $this->__setError(2, "$name doesn't exist");
        return null;
    }
/**
 * Returns all session variables.
 *
 * @return mixed Full $_SESSION array, or false on error.
 * @access private
 */
    function __returnSessionVars() {
        if (!empty($_SESSION)) {
            return $_SESSION;
        }
        $this->__setError(2, "No Session vars set");
        return false;
    }
/**
 * Tells Session to write a notification when a certain session path or subpath is written to
 *
 * @param mixed $var The variable path to watch
 * @return void
 * @access public
 */
    function watch($var) {
        $var = $this->__validateKeys($var);
        if (empty($var)) {
            return false;
        }
        if (!in_array($var, $this->watchKeys, true)) {
            $this->watchKeys[] = $var;
        }
    }
/**
 * Tells Session to stop watching a given key path
 *
 * @param mixed $var The variable path to watch
 * @return void
 * @access public
 */
    function ignore($var) {
        $var = $this->__validateKeys($var);
        if (!in_array($var, $this->watchKeys)) {
            return;
        }
        foreach ($this->watchKeys as $i => $key) {
            if ($key == $var) {
                unset($this->watchKeys[$i]);
                $this->watchKeys = array_values($this->watchKeys);
                return;
            }
        }
    }
/**
 * Writes value to given session variable name.
 *
 * @param mixed $name Name of variable
 * @param string $value Value to write
 * @return boolean True if the write was successful, false if the write failed
 * @access public
 */
    function write($name, $value) {
        $var = $this->__validateKeys($name);

        if (empty($var)) {
            return false;
        }
        if (in_array($var, $this->watchKeys)) {
            trigger_error('Writing session key {' . $var . '}: ' . Debugger::exportVar($value), E_USER_NOTICE);
        }
        $this->__overwrite($_SESSION, Set::insert($_SESSION, $var, $value));
        return (Set::extract($_SESSION, $var) === $value);
    }
/**
 * Helper method to destroy invalid sessions.
 *
 * @return void
 * @access public
 */
    function destroy() {
        $_SESSION = array();
        $this->__construct($this->path);
        $this->start();
        $this->renew();
        $this->_checkValid();
    }
/**
 * Helper method to initialize a session, based on Cake core settings.
 *
 * @access private
 */
    function __initSession() {
        $iniSet = function_exists('ini_set');

        if ($iniSet && env('HTTPS')) {
            ini_set('session.cookie_secure', 1);
        }

        switch ($this->security) {
            case 'high':
                $this->cookieLifeTime = 0;
                if ($iniSet) {
                    ini_set('session.referer_check', $this->host);
                }
            break;
            case 'medium':
                $this->cookieLifeTime = 7 * 86400;
                if ($iniSet) {
                    ini_set('session.referer_check', $this->host);
                }
            break;
            case 'low':
            default:
                $this->cookieLifeTime = 788940000;
            break;
        }

        switch (Configure::read('Session.save')) {
            case 'cake':
                if (empty($_SESSION)) {
                    if ($iniSet) {
                        ini_set('session.use_trans_sid', 0);
                        ini_set('url_rewriter.tags', '');
                        ini_set('session.serialize_handler', 'php');
                        ini_set('session.use_cookies', 1);
                        ini_set('session.name', Configure::read('Session.cookie'));
                        ini_set('session.cookie_lifetime', $this->cookieLifeTime);
                        ini_set('session.cookie_path', $this->path);
                        ini_set('session.auto_start', 0);
                        ini_set('session.save_path', TMP . 'sessions');
                    }
                }
            break;
            case 'database':
                if (empty($_SESSION)) {
                    if (Configure::read('Session.table') === null) {
                        trigger_error(__("You must set the all Configure::write('Session.*') in core.php to use database storage"), E_USER_WARNING);
                        exit();
                    } elseif (Configure::read('Session.database') === null) {
                        Configure::write('Session.database', 'default');
                    }
                    if ($iniSet) {
                        ini_set('session.use_trans_sid', 0);
                        ini_set('url_rewriter.tags', '');
                        ini_set('session.save_handler', 'user');
                        ini_set('session.serialize_handler', 'php');
                        ini_set('session.use_cookies', 1);
                        ini_set('session.name', Configure::read('Session.cookie'));
                        ini_set('session.cookie_lifetime', $this->cookieLifeTime);
                        ini_set('session.cookie_path', $this->path);
                        ini_set('session.auto_start', 0);
                    }
                }
                session_set_save_handler(array('CakeSession','__open'),
                                                    array('CakeSession', '__close'),
                                                    array('CakeSession', '__read'),
                                                    array('CakeSession', '__write'),
                                                    array('CakeSession', '__destroy'),
                                                    array('CakeSession', '__gc'));
            break;
            case 'php':
                if (empty($_SESSION)) {
                    if ($iniSet) {
                        ini_set('session.use_trans_sid', 0);
                        ini_set('session.name', Configure::read('Session.cookie'));
                        ini_set('session.cookie_lifetime', $this->cookieLifeTime);
                        ini_set('session.cookie_path', $this->path);
                    }
                }
            break;
            case 'cache':
                if (empty($_SESSION)) {
                    if (!class_exists('Cache')) {
                        uses('Cache');
                    }
                    if ($iniSet) {
                        ini_set('session.use_trans_sid', 0);
                        ini_set('url_rewriter.tags', '');
                        ini_set('session.save_handler', 'user');
                        ini_set('session.use_cookies', 1);
                        ini_set('session.name', Configure::read('Session.cookie'));
                        ini_set('session.cookie_lifetime', $this->cookieLifeTime);
                        ini_set('session.cookie_path', $this->path);
                    }
                }
                session_set_save_handler(array('CakeSession','__open'),
                                                    array('CakeSession', '__close'),
                                                    array('Cache', 'read'),
                                                    array('Cache', 'write'),
                                                    array('Cache', 'delete'),
                                                    array('Cache', 'gc'));
            break;
            default:
                if (empty($_SESSION)) {
                    $config = CONFIGS . Configure::read('Session.save') . '.php';

                    if (is_file($config)) {
                        require_once ($config);
                    }
                }
            break;
        }
    }
/**
 * Helper method to start a session
 *
 * @access private
 */
    function __startSession() {
        if (headers_sent()) {
            if (empty($_SESSION)) {
                $_SESSION = array();
            }
            return false;
        } elseif (!isset($_SESSION)) {
            session_cache_limiter ("must-revalidate");
            session_start();
            header ('P3P: CP="NOI ADM DEV PSAi COM NAV OUR OTRo STP IND DEM"');
            return true;
        } else {
            session_start();
            return true;
        }
    }
/**
 * Helper method to create a new session.
 *
 * @return void
 * @access protected
 */
    function _checkValid() {
        if ($this->read('Config')) {
            if ((Configure::read('Session.checkAgent') === false || $this->_userAgent == $this->read('Config.userAgent')) && $this->time <= $this->read('Config.time')) {
                $time = $this->read('Config.time');
                $this->write('Config.time', $this->sessionTime);

                if (Configure::read('Security.level') === 'high') {
                    $check = $this->read('Config.timeout');
                    $check = $check - 1;
                    $this->write('Config.timeout', $check);

                    if (time() > ($time - (Security::inactiveMins() * Configure::read('Session.timeout')) + 2) || $check < 1) {
                        $this->renew();
                        $this->write('Config.timeout', 10);
                    }
                }
                $this->valid = true;
            } else {
                $this->destroy();
                $this->valid = false;
                $this->__setError(1, 'Session Highjacking Attempted !!!');
            }
        } else {
            $this->write('Config.userAgent', $this->_userAgent);
            $this->write('Config.time', $this->sessionTime);
            $this->write('Config.timeout', 10);
            $this->valid = true;
            $this->__setError(1, 'Session is valid');
        }
    }
/**
 * Helper method to restart a session.
 *
 * @return void
 * @access private
 */
    function __regenerateId() {
        $oldSessionId = session_id();
        if ($oldSessionId) {
            $sessionpath = session_save_path();
            if (empty($sessionpath)) {
                $sessionpath = "/tmp";
            }
            if (session_id() != "" || isset($_COOKIE[session_name()])) {
                setcookie(Configure::read('Session.cookie'), '', time() - 42000, $this->path);
            }
            session_regenerate_id(true);
            if (PHP_VERSION < 5.1) {
                $newSessid = session_id();

                if (function_exists('session_write_close')) {
                    session_write_close();
                }
                $this->__initSession();
                session_id($oldSessionId);
                session_start();
                session_destroy();
                $file = $sessionpath . DS . "sess_$oldSessionId";
                @unlink($file);
                $this->__initSession();
                session_id($newSessid);
                session_start();
            }
        }
    }
/**
 * Restarts this session.
 *
 * @access public
 */
    function renew() {
        $this->__regenerateId();
    }
/**
 * Validate that the $name is in correct dot notation
 * example: $name = 'ControllerName.key';
 *
 * @param string $name Session key names as string.
 * @return mixed false is $name is not correct format, or $name if it is correct
 * @access private
 */
    function __validateKeys($name) {
        if (is_string($name) && preg_match("/^[ 0-9a-zA-Z._-]*$/", $name)) {
            return $name;
        }
        $this->__setError(3, "$name is not a string");
        return false;
    }
/**
 * Helper method to set an internal error message.
 *
 * @param integer $errorNumber Number of the error
 * @param string $errorMessage Description of the error
 * @return void
 * @access private
 */
    function __setError($errorNumber, $errorMessage) {
        if ($this->error === false) {
            $this->error = array();
        }
        $this->error[$errorNumber] = $errorMessage;
        $this->lastError = $errorNumber;
    }
/**
 * Method called on open of a database session.
 *
 * @return boolean Success
 * @access private
 */
    function __open() {
        return true;
    }
/**
 * Method called on close of a database session.
 *
 * @return boolean Success
 * @access private
 */
    function __close() {
        $probability = mt_rand(1, 150);
        if ($probability <= 3) {
            switch (Configure::read('Session.save')) {
                case 'cache':
                    Cache::gc();
                break;
                default:
                    CakeSession::__gc();
                break;
            }
        }
        return true;
    }
/**
 * Method used to read from a database session.
 *
 * @param mixed $key The key of the value to read
 * @return mixed The value of the key or false if it does not exist
 * @access private
 */
    function __read($key) {
        $db =& ConnectionManager::getDataSource(Configure::read('Session.database'));
        $table = $db->fullTableName(Configure::read('Session.table'), false);
        $row = $db->query("SELECT " . $db->name($table.'.data') . " FROM " . $db->name($table) . " WHERE " . $db->name($table.'.id') . " = " . $db->value($key), false);

        if ($row && !isset($row[0][$table]) && isset($row[0][0])) {
            $table = 0;
        }

        if ($row && $row[0][$table]['data']) {
            return $row[0][$table]['data'];
        } else {
            return false;
        }
    }
/**
 * Helper function called on write for database sessions.
 *
 * @param mixed $key The name of the var
 * @param mixed $value The value of the var
 * @return boolean Success
 * @access private
 */
    function __write($key, $value) {
        $db =& ConnectionManager::getDataSource(Configure::read('Session.database'));
        $table = $db->fullTableName(Configure::read('Session.table'));

        switch (Configure::read('Security.level')) {
            case 'high':
                $factor = 10;
            break;
            case 'medium':
                $factor = 100;
            break;
            case 'low':
                $factor = 300;
            break;
            default:
                $factor = 10;
            break;
        }
        $expires = time() +  Configure::read('Session.timeout') * $factor;
        $row = $db->query("SELECT COUNT(id) AS count FROM " . $db->name($table) . " WHERE "
                                 . $db->name('id') . " = "
                                 . $db->value($key), false);

        if ($row[0][0]['count'] > 0) {
            $db->execute("UPDATE " . $db->name($table) . " SET " . $db->name('data') . " = "
                                . $db->value($value) . ", " . $db->name('expires') . " = "
                                . $db->value($expires) . " WHERE " . $db->name('id') . " = "
                                . $db->value($key));
        } else {
            $db->execute("INSERT INTO " . $db->name($table) . " (" . $db->name('data') . ","
                                . $db->name('expires') . "," . $db->name('id')
                                . ") VALUES (" . $db->value($value) . ", " . $db->value($expires) . ", "
                                . $db->value($key) . ")");
        }
        return true;
    }
/**
 * Method called on the destruction of a database session.
 *
 * @param integer $key Key that uniquely identifies session in database
 * @return boolean Success
 * @access private
 */
    function __destroy($key) {
        $db =& ConnectionManager::getDataSource(Configure::read('Session.database'));
        $table = $db->fullTableName(Configure::read('Session.table'));
        $db->execute("DELETE FROM " . $db->name($table) . " WHERE " . $db->name($table.'.id') . " = " . $db->value($key));
        return true;
    }
/**
 * Helper function called on gc for database sessions.
 *
 * @param integer $expires Timestamp (defaults to current time)
 * @return boolean Success
 * @access private
 */
    function __gc($expires = null) {
        $db =& ConnectionManager::getDataSource(Configure::read('Session.database'));
        $table = $db->fullTableName(Configure::read('Session.table'));
        $db->execute("DELETE FROM " . $db->name($table) . " WHERE " . $db->name($table.'.expires') . " < ". $db->value(time()));
        return true;
     }
}
?>

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