system/libraries/Session/drivers/Session_cookie.php - code-igniter-v3-giggi - Gitiles

 <?php
 /**
  * CodeIgniter
  *
  * An open source application development framework for PHP 5.2.4 or newer
  *
  * This content is released under the MIT License (MIT)
  *
  * Copyright (c) 2014, British Columbia Institute of Technology
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  *
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
  * @copyright	Copyright (c) 2014, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
  * @link	http://codeigniter.com
  * @since	Version 1.0.0
  * @filesource
  */
 defined('BASEPATH') OR exit('No direct script access allowed');

 /**
  * Cookie-based session management driver
  *
  * This is the classic CI_Session functionality, as written by EllisLab, abstracted out to a driver.
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
  * @category	Sessions
  * @author		EllisLab Dev Team
  * @link		http://codeigniter.com/user_guide/libraries/sessions.html
  */
 class CI_Session_cookie extends CI_Session_driver {

 	/**
 	 * Whether to encrypt the session cookie
 	 *
 	 * @var bool
 	 */
 	public $sess_encrypt_cookie		= FALSE;

 	/**
 	 * Whether to use to the database for session storage
 	 *
 	 * @var bool
 	 */
 	public $sess_use_database		= FALSE;

 	/**
 	 * Name of the database table in which to store sessions
 	 *
 	 * @var string
 	 */
 	public $sess_table_name			= '';

 	/**
 	 * Length of time (in seconds) for sessions to expire
 	 *
 	 * @var int
 	 */
 	public $sess_expiration			= 7200;

 	/**
 	 * Whether to kill session on close of browser window
 	 *
 	 * @var bool
 	 */
 	public $sess_expire_on_close	= FALSE;

 	/**
 	 * Whether to match session on ip address
 	 *
 	 * @var bool
 	 */
 	public $sess_match_ip			= FALSE;

 	/**
 	 * Whether to match session on user-agent
 	 *
 	 * @var bool
 	 */
 	public $sess_match_useragent	= TRUE;

 	/**
 	 * Name of session cookie
 	 *
 	 * @var string
 	 */
 	public $sess_cookie_name		= 'ci_session';

 	/**
 	 * Session cookie prefix
 	 *
 	 * @var string
 	 */
 	public $cookie_prefix			= '';

 	/**
 	 * Session cookie path
 	 *
 	 * @var string
 	 */
 	public $cookie_path				= '';

 	/**
 	 * Session cookie domain
 	 *
 	 * @var string
 	 */
 	public $cookie_domain			= '';

 	/**
 	 * Whether to set the cookie only on HTTPS connections
 	 *
 	 * @var bool
 	 */
 	public $cookie_secure			= FALSE;

 	/**
 	 * Whether cookie should be allowed only to be sent by the server
 	 *
 	 * @var bool
 	 */
 	public $cookie_httponly 		= FALSE;

 	/**
 	 * Interval at which to update session
 	 *
 	 * @var int
 	 */
 	public $sess_time_to_update		= 300;

 	/**
 	 * Key with which to encrypt the session cookie
 	 *
 	 * @var string
 	 */
 	public $encryption_key			= '';

 	/**
 	 * Timezone to use for the current time
 	 *
 	 * @var string
 	 */
 	public $time_reference			= 'local';

 	/**
 	 * Session data
 	 *
 	 * @var array
 	 */
 	public $userdata				= array();

 	/**
 	 * Current time
 	 *
 	 * @var int
 	 */
 	public $now;

 	// ------------------------------------------------------------------------

 	/**
 	 * Default userdata keys
 	 *
 	 * @var	array
 	 */
 	protected $defaults = array(
 		'session_id' => NULL,
 		'ip_address' => NULL,
 		'user_agent' => NULL,
 		'last_activity' => NULL
 	);

 	/**
 	 * Data needs DB update flag
 	 *
 	 * @var	bool
 	 */
 	protected $data_dirty = FALSE;

 	/**
 	 * Standardize newlines flag
 	 *
 	 * @var	bool
 	 */
 	protected $_standardize_newlines;

 	// ------------------------------------------------------------------------

 	/**
 	 * Initialize session driver object
 	 *
 	 * @return	void
 	 */
 	protected function initialize()
 	{
 		// Set all the session preferences, which can either be set
 		// manually via the $params array or via the config file
 		$prefs = array(
 			'sess_encrypt_cookie',
 			'sess_use_database',
 			'sess_table_name',
 			'sess_expiration',
 			'sess_expire_on_close',
 			'sess_match_ip',
 			'sess_match_useragent',
 			'sess_cookie_name',
 			'cookie_path',
 			'cookie_domain',
 			'cookie_secure',
 			'cookie_httponly',
 			'sess_time_to_update',
 			'time_reference',
 			'cookie_prefix',
 			'encryption_key',
 		);

 		$this->_standardize_newlines = (bool) config_item('standardize_newlines');

 		foreach ($prefs as $key)
 		{
 			$this->$key = isset($this->_parent->params[$key])
 				? $this->_parent->params[$key]
 				: $this->CI->config->item($key);
 		}

 		if (empty($this->encryption_key))
 		{
 			show_error('In order to use the Cookie Session driver you are required to set an encryption key in your config file.');
 		}

 		// Do we need encryption? If so, load the encryption class
 		if ($this->sess_encrypt_cookie === TRUE)
 		{
 			$this->CI->load->library('encryption');
 		}

 		// Check for database
 		if ($this->sess_use_database === TRUE && $this->sess_table_name !== '')
 		{
 			// Load database driver
 			$this->CI->load->database();

 			// Register shutdown function
 			register_shutdown_function(array($this, '_update_db'));
 		}

 		// Set the "now" time. Can either be GMT or server time, based on the config prefs.
 		// We use this to set the "last activity" time
 		$this->now = $this->_get_time();

 		// Set the session length. If the session expiration is
 		// set to zero we'll set the expiration two years from now.
 		if ($this->sess_expiration === 0)
 		{
 			$this->sess_expiration = (60*60*24*365*2);
 		}

 		// Set the cookie name
 		$this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name;

 		// Run the Session routine. If a session doesn't exist we'll
 		// create a new one. If it does, we'll update it.
 		if ( ! $this->_sess_read())
 		{
 			$this->_sess_create();
 		}
 		else
 		{
 			$this->_sess_update();
 		}

 		// Delete expired sessions if necessary
 		$this->_sess_gc();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Write the session data
 	 *
 	 * @return	void
 	 */
 	public function sess_save()
 	{
 		// Check for database
 		if ($this->sess_use_database === TRUE)
 		{
 			// Mark custom data as dirty so we know to update the DB
 			$this->data_dirty = TRUE;
 		}

 		// Write the cookie
 		$this->_set_cookie();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Destroy the current session
 	 *
 	 * @return	void
 	 */
 	public function sess_destroy()
 	{
 		// Kill the session DB row
 		if ($this->sess_use_database === TRUE && isset($this->userdata['session_id']))
 		{
 			$this->CI->db->delete($this->sess_table_name, array('session_id' => $this->userdata['session_id']));
 			$this->data_dirty = FALSE;
 		}

 		// Kill the cookie
 		$this->_setcookie($this->sess_cookie_name, '', ($this->now - 31500000),
 			$this->cookie_path, $this->cookie_domain, 0);

 		// Kill session data
 		$this->userdata = array();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Regenerate the current session
 	 *
 	 * Regenerate the session id
 	 *
 	 * @param	bool	Destroy session data flag (default: false)
 	 * @return	void
 	 */
 	public function sess_regenerate($destroy = FALSE)
 	{
 		// Check destroy flag
 		if ($destroy)
 		{
 			// Destroy old session and create new one
 			$this->sess_destroy();
 			$this->_sess_create();
 		}
 		else
 		{
 			// Just force an update to recreate the id
 			$this->_sess_update(TRUE);
 		}
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Get a reference to user data array
 	 *
 	 * @return	array	Reference to userdata
 	 */
 	public function &get_userdata()
 	{
 		return $this->userdata;
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Fetch the current session data if it exists
 	 *
 	 * @return	bool
 	 */
 	protected function _sess_read()
 	{
 		// Fetch the cookie
 		$session = $this->CI->input->cookie($this->sess_cookie_name);

 		// No cookie? Goodbye cruel world!...
 		if ($session === NULL)
 		{
 			log_message('debug', 'A session cookie was not found.');
 			return FALSE;
 		}

 		if ($this->sess_encrypt_cookie === TRUE)
 		{
 			$session = $this->CI->encryption->decrypt($session);
 			if ($session === FALSE)
 			{
 				log_message('error', 'Session: Unable to decrypt the session cookie, possibly due to a HMAC mismatch.');
 				return FALSE;
 			}
 		}
 		else
 		{
 			if (($len = strlen($session) - 40) <= 0)
 			{
 				log_message('error', 'Session: The session cookie was not signed.');
 				return FALSE;
 			}

 			// Check cookie authentication
 			$hmac = substr($session, $len);
 			$session = substr($session, 0, $len);

 			// Time-attack-safe comparison
 			$hmac_check = hash_hmac('sha1', $session, $this->encryption_key);
 			$diff = 0;
 			for ($i = 0; $i < 40; $i++)
 			{
 				$diff |= ord($hmac[$i]) ^ ord($hmac_check[$i]);
 			}

 			if ($diff !== 0)
 			{
 				log_message('error', 'Session: HMAC mismatch. The session cookie data did not match what was expected.');
 				$this->sess_destroy();
 				return FALSE;
 			}
 		}

 		// Unserialize the session array
 		$session = @unserialize($session);

 		// Is the session data we unserialized an array with the correct format?
 		if ( ! is_array($session) OR ! isset($session['session_id'], $session['ip_address'], $session['user_agent'], $session['last_activity']))
 		{
 			log_message('debug', 'Session: Wrong cookie data format');
 			$this->sess_destroy();
 			return FALSE;
 		}

 		// Is the session current?
 		if (($session['last_activity'] + $this->sess_expiration) < $this->now OR $session['last_activity'] > $this->now)
 		{
 			log_message('debug', 'Session: Expired');
 			$this->sess_destroy();
 			return FALSE;
 		}

 		// Does the IP match?
 		if ($this->sess_match_ip === TRUE && $session['ip_address'] !== $this->CI->input->ip_address())
 		{
 			log_message('debug', 'Session: IP address mismatch');
 			$this->sess_destroy();
 			return FALSE;
 		}

 		// Does the User Agent Match?
 		if ($this->sess_match_useragent === TRUE &&
 			trim($session['user_agent']) !== trim(substr($this->CI->input->user_agent(), 0, 120)))
 		{
 			log_message('debug', 'Session: User Agent string mismatch');
 			$this->sess_destroy();
 			return FALSE;
 		}

 		// Is there a corresponding session in the DB?
 		if ($this->sess_use_database === TRUE)
 		{
 			$this->CI->db->where('session_id', $session['session_id']);

 			if ($this->sess_match_ip === TRUE)
 			{
 				$this->CI->db->where('ip_address', $session['ip_address']);
 			}

 			if ($this->sess_match_useragent === TRUE)
 			{
 				$this->CI->db->where('user_agent', $session['user_agent']);
 			}

 			// Is caching in effect? Turn it off
 			$db_cache = $this->CI->db->cache_on;
 			$this->CI->db->cache_off();

 			$query = $this->CI->db->limit(1)->get($this->sess_table_name);

 			// Was caching in effect?
 			if ($db_cache)
 			{
 				// Turn it back on
 				$this->CI->db->cache_on();
 			}

 			// No result? Kill it!
 			if (empty($query) OR $query->num_rows() === 0)
 			{
 				log_message('debug', 'Session: No match found in our database');
 				$this->sess_destroy();
 				return FALSE;
 			}

 			// Is there custom data? If so, add it to the main session array
 			$row = $query->row();
 			if ( ! empty($row->user_data))
 			{
 				$custom_data = unserialize(trim($row->user_data));

 				if (is_array($custom_data))
 				{
 					$session = $session + $custom_data;
 				}
 			}
 		}

 		// Session is valid!
 		$this->userdata = $session;
 		return TRUE;
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Create a new session
 	 *
 	 * @return	void
 	 */
 	protected function _sess_create()
 	{
 		// Initialize userdata
 		$this->userdata = array(
 			'session_id'	=> $this->_make_sess_id(),
 			'ip_address'	=> $this->CI->input->ip_address(),
 			'user_agent'	=> trim(substr($this->CI->input->user_agent(), 0, 120)),
 			'last_activity'	=> $this->now,
 		);

 		log_message('debug', 'Session: Creating new session ('.$this->userdata['session_id'].')');

 		// Check for database
 		if ($this->sess_use_database === TRUE)
 		{
 			// Add empty user_data field and save the data to the DB
 			$this->CI->db->set('user_data', '')->insert($this->sess_table_name, $this->userdata);
 		}

 		// Write the cookie
 		$this->_set_cookie();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Update an existing session
 	 *
 	 * @param	bool	Force update flag (default: false)
 	 * @return	void
 	 */
 	protected function _sess_update($force = FALSE)
 	{
 		// We only update the session every five minutes by default (unless forced)
 		if ( ! $force && ($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)
 		{
 			return;
 		}

 		// Update last activity to now
 		$this->userdata['last_activity'] = $this->now;

 		// Save the old session id so we know which DB record to update
 		$old_sessid = $this->userdata['session_id'];

 		// Changing the session ID during an AJAX call causes problems
 		if ( ! $this->CI->input->is_ajax_request())
 		{
 			// Get new id
 			$this->userdata['session_id'] = $this->_make_sess_id();

 			log_message('debug', 'Session: Regenerate ID');
 		}

 		// Check for database
 		if ($this->sess_use_database === TRUE)
 		{
 			$this->CI->db->where('session_id', $old_sessid);

 			if ($this->sess_match_ip === TRUE)
 			{
 				$this->CI->db->where('ip_address', $this->CI->input->ip_address());
 			}

 			if ($this->sess_match_useragent === TRUE)
 			{
 				$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
 			}

 			// Update the session ID and last_activity field in the DB
 			$this->CI->db->update($this->sess_table_name,
 				array(
 					'last_activity' => $this->now,
 					'session_id' => $this->userdata['session_id']
 				)
 			);
 		}

 		// Write the cookie
 		$this->_set_cookie();
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Update database with current data
 	 *
 	 * This gets called from the shutdown function and also
 	 * registered with PHP to run at the end of the request
 	 * so it's guaranteed to update even when a fatal error
 	 * occurs. The first call makes the update and clears the
 	 * dirty flag so it won't happen twice.
 	 *
 	 * @return	void
 	 */
 	public function _update_db()
 	{
 		// Check for database and dirty flag and unsaved
 		if ($this->sess_use_database === TRUE && $this->data_dirty === TRUE)
 		{
 			// Set up activity and data fields to be set
 			// If we don't find custom data, user_data will remain an empty string
 			$set = array(
 				'last_activity' => $this->userdata['last_activity'],
 				'user_data' => ''
 			);

 			// Get the custom userdata, leaving out the defaults
 			// (which get stored in the cookie)
 			$userdata = array_diff_key($this->userdata, $this->defaults);

 			// Did we find any custom data?
 			if ( ! empty($userdata))
 			{
 				// Serialize the custom data array so we can store it
 				$set['user_data'] = serialize($userdata);
 			}

 			// Reset query builder values.
 			$this->CI->db->reset_query();

 			// Run the update query
 			// Any time we change the session id, it gets updated immediately,
 			// so our where clause below is always safe
 			$this->CI->db->where('session_id', $this->userdata['session_id']);

 			if ($this->sess_match_ip === TRUE)
 			{
 				$this->CI->db->where('ip_address', $this->CI->input->ip_address());
 			}

 			if ($this->sess_match_useragent === TRUE)
 			{
 				$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
 			}

 			$this->CI->db->update($this->sess_table_name, $set);

 			// Clear dirty flag to prevent double updates
 			$this->data_dirty = FALSE;

 			log_message('debug', 'CI_Session Data Saved To DB');
 		}
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Generate a new session id
 	 *
 	 * @return	string	Hashed session id
 	 */
 	protected function _make_sess_id()
 	{
 		$new_sessid = '';
 		do
 		{
 			$new_sessid .= mt_rand();
 		}
 		while (strlen($new_sessid) < 32);

 		// To make the session ID even more secure we'll combine it with the user's IP
 		$new_sessid .= $this->CI->input->ip_address();

 		// Turn it into a hash and return
 		return md5(uniqid($new_sessid, TRUE));
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Get the "now" time
 	 *
 	 * @return	int	 Time
 	 */
 	protected function _get_time()
 	{
 		if ($this->time_reference === 'local' OR $this->time_reference === date_default_timezone_get())
 		{
 			return time();
 		}

 		$datetime = new DateTime('now', new DateTimeZone($this->time_reference));
 		sscanf($datetime->format('j-n-Y G:i:s'), '%d-%d-%d %d:%d:%d', $day, $month, $year, $hour, $minute, $second);

 		return mktime($hour, $minute, $second, $month, $day, $year);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Write the session cookie
 	 *
 	 * @return	void
 	 */
 	protected function _set_cookie()
 	{
 		// Get userdata (only defaults if database)
 		$cookie_data = ($this->sess_use_database === TRUE)
 				? array_intersect_key($this->userdata, $this->defaults)
 				: $this->userdata;

 		// The Input class will do this and since we use HMAC verification,
 		// unless we standardize here as well, the hash won't match.
 		if ($this->_standardize_newlines)
 		{
 			foreach (array_keys($this->userdata) as $key)
 			{
 				$this->userdata[$key] = preg_replace('/(?:\r\n|[\r\n])/', PHP_EOL, $this->userdata[$key]);
 			}
 		}

 		// Serialize the userdata for the cookie
 		$cookie_data = serialize($cookie_data);

 		if ($this->sess_encrypt_cookie === TRUE)
 		{
 			$cookie_data = $this->CI->encryption->encrypt($cookie_data);
 		}
 		else
 		{
 			// Require message authentication
 			$cookie_data .= hash_hmac('sha1', $cookie_data, $this->encryption_key);
 		}

 		$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();

 		// Set the cookie
 		$this->_setcookie($this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain,
 			$this->cookie_secure, $this->cookie_httponly);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Set a cookie with the system
 	 *
 	 * This abstraction of the setcookie call allows overriding for unit testing
 	 *
 	 * @param	string	Cookie name
 	 * @param	string	Cookie value
 	 * @param	int	Expiration time
 	 * @param	string	Cookie path
 	 * @param	string	Cookie domain
 	 * @param	bool	Secure connection flag
 	 * @param	bool	HTTP protocol only flag
 	 * @return	void
 	 */
 	protected function _setcookie($name, $value = '', $expire = 0, $path = '', $domain = '', $secure = FALSE, $httponly = FALSE)
 	{
 		setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
 	}

 	// ------------------------------------------------------------------------

 	/**
 	 * Garbage collection
 	 *
 	 * This deletes expired session rows from database
 	 * if the probability percentage is met
 	 *
 	 * @return	void
 	 */
 	protected function _sess_gc()
 	{
 		if ($this->sess_use_database !== TRUE)
 		{
 			return;
 		}

 		$probability = ini_get('session.gc_probability');
 		$divisor = ini_get('session.gc_divisor');

 		if (mt_rand(1, $divisor) <= $probability)
 		{
 			$expire = $this->now - $this->sess_expiration;
 			$this->CI->db->delete($this->sess_table_name, 'last_activity < '.$expire);

 			log_message('debug', 'Session garbage collection performed.');
 		}
 	}

 }

 /* End of file Session_cookie.php */
 /* Location: ./system/libraries/Session/drivers/Session_cookie.php */
	<?php
	/**
	* CodeIgniter
	*
	* An open source application development framework for PHP 5.2.4 or newer
	*
	* This content is released under the MIT License (MIT)
	*
	* Copyright (c) 2014, British Columbia Institute of Technology
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*
	* @package CodeIgniter
	* @author EllisLab Dev Team
	* @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
	* @copyright Copyright (c) 2014, British Columbia Institute of Technology (http://bcit.ca/)
	* @license http://opensource.org/licenses/MIT MIT License
	* @link http://codeigniter.com
	* @since Version 1.0.0
	* @filesource
	*/
	defined('BASEPATH') OR exit('No direct script access allowed');

	/**
	* Cookie-based session management driver
	*
	* This is the classic CI_Session functionality, as written by EllisLab, abstracted out to a driver.
	*
	* @package CodeIgniter
	* @subpackage Libraries
	* @category Sessions
	* @author EllisLab Dev Team
	* @link http://codeigniter.com/user_guide/libraries/sessions.html
	*/
	class CI_Session_cookie extends CI_Session_driver {

	/**
	* Whether to encrypt the session cookie
	*
	* @var bool
	*/
	public $sess_encrypt_cookie = FALSE;

	/**
	* Whether to use to the database for session storage
	*
	* @var bool
	*/
	public $sess_use_database = FALSE;

	/**
	* Name of the database table in which to store sessions
	*
	* @var string
	*/
	public $sess_table_name = '';

	/**
	* Length of time (in seconds) for sessions to expire
	*
	* @var int
	*/
	public $sess_expiration = 7200;

	/**
	* Whether to kill session on close of browser window
	*
	* @var bool
	*/
	public $sess_expire_on_close = FALSE;

	/**
	* Whether to match session on ip address
	*
	* @var bool
	*/
	public $sess_match_ip = FALSE;

	/**
	* Whether to match session on user-agent
	*
	* @var bool
	*/
	public $sess_match_useragent = TRUE;

	/**
	* Name of session cookie
	*
	* @var string
	*/
	public $sess_cookie_name = 'ci_session';

	/**
	* Session cookie prefix
	*
	* @var string
	*/
	public $cookie_prefix = '';

	/**
	* Session cookie path
	*
	* @var string
	*/
	public $cookie_path = '';

	/**
	* Session cookie domain
	*
	* @var string
	*/
	public $cookie_domain = '';

	/**
	* Whether to set the cookie only on HTTPS connections
	*
	* @var bool
	*/
	public $cookie_secure = FALSE;

	/**
	* Whether cookie should be allowed only to be sent by the server
	*
	* @var bool
	*/
	public $cookie_httponly = FALSE;

	/**
	* Interval at which to update session
	*
	* @var int
	*/
	public $sess_time_to_update = 300;

	/**
	* Key with which to encrypt the session cookie
	*
	* @var string
	*/
	public $encryption_key = '';

	/**
	* Timezone to use for the current time
	*
	* @var string
	*/
	public $time_reference = 'local';

	/**
	* Session data
	*
	* @var array
	*/
	public $userdata = array();

	/**
	* Current time
	*
	* @var int
	*/
	public $now;

	// ------------------------------------------------------------------------

	/**
	* Default userdata keys
	*
	* @var array
	*/
	protected $defaults = array(
	'session_id' => NULL,
	'ip_address' => NULL,
	'user_agent' => NULL,
	'last_activity' => NULL
	);

	/**
	* Data needs DB update flag
	*
	* @var bool
	*/
	protected $data_dirty = FALSE;

	/**
	* Standardize newlines flag
	*
	* @var bool
	*/
	protected $_standardize_newlines;

	// ------------------------------------------------------------------------

	/**
	* Initialize session driver object
	*
	* @return void
	*/
	protected function initialize()
	{
	// Set all the session preferences, which can either be set
	// manually via the $params array or via the config file
	$prefs = array(
	'sess_encrypt_cookie',
	'sess_use_database',
	'sess_table_name',
	'sess_expiration',
	'sess_expire_on_close',
	'sess_match_ip',
	'sess_match_useragent',
	'sess_cookie_name',
	'cookie_path',
	'cookie_domain',
	'cookie_secure',
	'cookie_httponly',
	'sess_time_to_update',
	'time_reference',
	'cookie_prefix',
	'encryption_key',
	);

	$this->_standardize_newlines = (bool) config_item('standardize_newlines');

	foreach ($prefs as $key)
	{
	$this->$key = isset($this->_parent->params[$key])
	? $this->_parent->params[$key]
	: $this->CI->config->item($key);
	}

	if (empty($this->encryption_key))
	{
	show_error('In order to use the Cookie Session driver you are required to set an encryption key in your config file.');
	}

	// Do we need encryption? If so, load the encryption class
	if ($this->sess_encrypt_cookie === TRUE)
	{
	$this->CI->load->library('encryption');
	}

	// Check for database
	if ($this->sess_use_database === TRUE && $this->sess_table_name !== '')
	{
	// Load database driver
	$this->CI->load->database();

	// Register shutdown function
	register_shutdown_function(array($this, '_update_db'));
	}

	// Set the "now" time. Can either be GMT or server time, based on the config prefs.
	// We use this to set the "last activity" time
	$this->now = $this->_get_time();

	// Set the session length. If the session expiration is
	// set to zero we'll set the expiration two years from now.
	if ($this->sess_expiration === 0)
	{
	$this->sess_expiration = (6060243652);
	}

	// Set the cookie name
	$this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name;

	// Run the Session routine. If a session doesn't exist we'll
	// create a new one. If it does, we'll update it.
	if ( ! $this->_sess_read())
	{
	$this->_sess_create();
	}
	else
	{
	$this->_sess_update();
	}

	// Delete expired sessions if necessary
	$this->_sess_gc();
	}

	// ------------------------------------------------------------------------

	/**
	* Write the session data
	*
	* @return void
	*/
	public function sess_save()
	{
	// Check for database
	if ($this->sess_use_database === TRUE)
	{
	// Mark custom data as dirty so we know to update the DB
	$this->data_dirty = TRUE;
	}

	// Write the cookie
	$this->_set_cookie();
	}

	// ------------------------------------------------------------------------

	/**
	* Destroy the current session
	*
	* @return void
	*/
	public function sess_destroy()
	{
	// Kill the session DB row
	if ($this->sess_use_database === TRUE && isset($this->userdata['session_id']))
	{
	$this->CI->db->delete($this->sess_table_name, array('session_id' => $this->userdata['session_id']));
	$this->data_dirty = FALSE;
	}

	// Kill the cookie
	$this->_setcookie($this->sess_cookie_name, '', ($this->now - 31500000),
	$this->cookie_path, $this->cookie_domain, 0);

	// Kill session data
	$this->userdata = array();
	}

	// ------------------------------------------------------------------------

	/**
	* Regenerate the current session
	*
	* Regenerate the session id
	*
	* @param bool Destroy session data flag (default: false)
	* @return void
	*/
	public function sess_regenerate($destroy = FALSE)
	{
	// Check destroy flag
	if ($destroy)
	{
	// Destroy old session and create new one
	$this->sess_destroy();
	$this->_sess_create();
	}
	else
	{
	// Just force an update to recreate the id
	$this->_sess_update(TRUE);
	}
	}

	// ------------------------------------------------------------------------

	/**
	* Get a reference to user data array
	*
	* @return array Reference to userdata
	*/
	public function &get_userdata()
	{
	return $this->userdata;
	}

	// ------------------------------------------------------------------------

	/**
	* Fetch the current session data if it exists
	*
	* @return bool
	*/
	protected function _sess_read()
	{
	// Fetch the cookie
	$session = $this->CI->input->cookie($this->sess_cookie_name);

	// No cookie? Goodbye cruel world!...
	if ($session === NULL)
	{
	log_message('debug', 'A session cookie was not found.');
	return FALSE;
	}

	if ($this->sess_encrypt_cookie === TRUE)
	{
	$session = $this->CI->encryption->decrypt($session);
	if ($session === FALSE)
	{
	log_message('error', 'Session: Unable to decrypt the session cookie, possibly due to a HMAC mismatch.');
	return FALSE;
	}
	}
	else
	{
	if (($len = strlen($session) - 40) <= 0)
	{
	log_message('error', 'Session: The session cookie was not signed.');
	return FALSE;
	}

	// Check cookie authentication
	$hmac = substr($session, $len);
	$session = substr($session, 0, $len);

	// Time-attack-safe comparison
	$hmac_check = hash_hmac('sha1', $session, $this->encryption_key);
	$diff = 0;
	for ($i = 0; $i < 40; $i++)
	{
	$diff \|= ord($hmac[$i]) ^ ord($hmac_check[$i]);
	}

	if ($diff !== 0)
	{
	log_message('error', 'Session: HMAC mismatch. The session cookie data did not match what was expected.');
	$this->sess_destroy();
	return FALSE;
	}
	}

	// Unserialize the session array
	$session = @unserialize($session);

	// Is the session data we unserialized an array with the correct format?
	if ( ! is_array($session) OR ! isset($session['session_id'], $session['ip_address'], $session['user_agent'], $session['last_activity']))
	{
	log_message('debug', 'Session: Wrong cookie data format');
	$this->sess_destroy();
	return FALSE;
	}

	// Is the session current?
	if (($session['last_activity'] + $this->sess_expiration) < $this->now OR $session['last_activity'] > $this->now)
	{
	log_message('debug', 'Session: Expired');
	$this->sess_destroy();
	return FALSE;
	}

	// Does the IP match?
	if ($this->sess_match_ip === TRUE && $session['ip_address'] !== $this->CI->input->ip_address())
	{
	log_message('debug', 'Session: IP address mismatch');
	$this->sess_destroy();
	return FALSE;
	}

	// Does the User Agent Match?
	if ($this->sess_match_useragent === TRUE &&
	trim($session['user_agent']) !== trim(substr($this->CI->input->user_agent(), 0, 120)))
	{
	log_message('debug', 'Session: User Agent string mismatch');
	$this->sess_destroy();
	return FALSE;
	}

	// Is there a corresponding session in the DB?
	if ($this->sess_use_database === TRUE)
	{
	$this->CI->db->where('session_id', $session['session_id']);

	if ($this->sess_match_ip === TRUE)
	{
	$this->CI->db->where('ip_address', $session['ip_address']);
	}

	if ($this->sess_match_useragent === TRUE)
	{
	$this->CI->db->where('user_agent', $session['user_agent']);
	}

	// Is caching in effect? Turn it off
	$db_cache = $this->CI->db->cache_on;
	$this->CI->db->cache_off();

	$query = $this->CI->db->limit(1)->get($this->sess_table_name);

	// Was caching in effect?
	if ($db_cache)
	{
	// Turn it back on
	$this->CI->db->cache_on();
	}

	// No result? Kill it!
	if (empty($query) OR $query->num_rows() === 0)
	{
	log_message('debug', 'Session: No match found in our database');
	$this->sess_destroy();
	return FALSE;
	}

	// Is there custom data? If so, add it to the main session array
	$row = $query->row();
	if ( ! empty($row->user_data))
	{
	$custom_data = unserialize(trim($row->user_data));

	if (is_array($custom_data))
	{
	$session = $session + $custom_data;
	}
	}
	}

	// Session is valid!
	$this->userdata = $session;
	return TRUE;
	}

	// ------------------------------------------------------------------------

	/**
	* Create a new session
	*
	* @return void
	*/
	protected function _sess_create()
	{
	// Initialize userdata
	$this->userdata = array(
	'session_id' => $this->_make_sess_id(),
	'ip_address' => $this->CI->input->ip_address(),
	'user_agent' => trim(substr($this->CI->input->user_agent(), 0, 120)),
	'last_activity' => $this->now,
	);

	log_message('debug', 'Session: Creating new session ('.$this->userdata['session_id'].')');

	// Check for database
	if ($this->sess_use_database === TRUE)
	{
	// Add empty user_data field and save the data to the DB
	$this->CI->db->set('user_data', '')->insert($this->sess_table_name, $this->userdata);
	}

	// Write the cookie
	$this->_set_cookie();
	}

	// ------------------------------------------------------------------------

	/**
	* Update an existing session
	*
	* @param bool Force update flag (default: false)
	* @return void
	*/
	protected function _sess_update($force = FALSE)
	{
	// We only update the session every five minutes by default (unless forced)
	if ( ! $force && ($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)
	{
	return;
	}

	// Update last activity to now
	$this->userdata['last_activity'] = $this->now;

	// Save the old session id so we know which DB record to update
	$old_sessid = $this->userdata['session_id'];

	// Changing the session ID during an AJAX call causes problems
	if ( ! $this->CI->input->is_ajax_request())
	{
	// Get new id
	$this->userdata['session_id'] = $this->_make_sess_id();

	log_message('debug', 'Session: Regenerate ID');
	}

	// Check for database
	if ($this->sess_use_database === TRUE)
	{
	$this->CI->db->where('session_id', $old_sessid);

	if ($this->sess_match_ip === TRUE)
	{
	$this->CI->db->where('ip_address', $this->CI->input->ip_address());
	}

	if ($this->sess_match_useragent === TRUE)
	{
	$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
	}

	// Update the session ID and last_activity field in the DB
	$this->CI->db->update($this->sess_table_name,
	array(
	'last_activity' => $this->now,
	'session_id' => $this->userdata['session_id']
	)
	);
	}

	// Write the cookie
	$this->_set_cookie();
	}

	// ------------------------------------------------------------------------

	/**
	* Update database with current data
	*
	* This gets called from the shutdown function and also
	* registered with PHP to run at the end of the request
	* so it's guaranteed to update even when a fatal error
	* occurs. The first call makes the update and clears the
	* dirty flag so it won't happen twice.
	*
	* @return void
	*/
	public function _update_db()
	{
	// Check for database and dirty flag and unsaved
	if ($this->sess_use_database === TRUE && $this->data_dirty === TRUE)
	{
	// Set up activity and data fields to be set
	// If we don't find custom data, user_data will remain an empty string
	$set = array(
	'last_activity' => $this->userdata['last_activity'],
	'user_data' => ''
	);

	// Get the custom userdata, leaving out the defaults
	// (which get stored in the cookie)
	$userdata = array_diff_key($this->userdata, $this->defaults);

	// Did we find any custom data?
	if ( ! empty($userdata))
	{
	// Serialize the custom data array so we can store it
	$set['user_data'] = serialize($userdata);
	}

	// Reset query builder values.
	$this->CI->db->reset_query();

	// Run the update query
	// Any time we change the session id, it gets updated immediately,
	// so our where clause below is always safe
	$this->CI->db->where('session_id', $this->userdata['session_id']);

	if ($this->sess_match_ip === TRUE)
	{
	$this->CI->db->where('ip_address', $this->CI->input->ip_address());
	}

	if ($this->sess_match_useragent === TRUE)
	{
	$this->CI->db->where('user_agent', trim(substr($this->CI->input->user_agent(), 0, 120)));
	}

	$this->CI->db->update($this->sess_table_name, $set);

	// Clear dirty flag to prevent double updates
	$this->data_dirty = FALSE;

	log_message('debug', 'CI_Session Data Saved To DB');
	}
	}

	// ------------------------------------------------------------------------

	/**
	* Generate a new session id
	*
	* @return string Hashed session id
	*/
	protected function _make_sess_id()
	{
	$new_sessid = '';
	do
	{
	$new_sessid .= mt_rand();
	}
	while (strlen($new_sessid) < 32);

	// To make the session ID even more secure we'll combine it with the user's IP
	$new_sessid .= $this->CI->input->ip_address();

	// Turn it into a hash and return
	return md5(uniqid($new_sessid, TRUE));
	}

	// ------------------------------------------------------------------------

	/**
	* Get the "now" time
	*
	* @return int Time
	*/
	protected function _get_time()
	{
	if ($this->time_reference === 'local' OR $this->time_reference === date_default_timezone_get())
	{
	return time();
	}

	$datetime = new DateTime('now', new DateTimeZone($this->time_reference));
	sscanf($datetime->format('j-n-Y G:i:s'), '%d-%d-%d %d:%d:%d', $day, $month, $year, $hour, $minute, $second);

	return mktime($hour, $minute, $second, $month, $day, $year);
	}

	// ------------------------------------------------------------------------

	/**
	* Write the session cookie
	*
	* @return void
	*/
	protected function _set_cookie()
	{
	// Get userdata (only defaults if database)
	$cookie_data = ($this->sess_use_database === TRUE)
	? array_intersect_key($this->userdata, $this->defaults)
	: $this->userdata;

	// The Input class will do this and since we use HMAC verification,
	// unless we standardize here as well, the hash won't match.
	if ($this->_standardize_newlines)
	{
	foreach (array_keys($this->userdata) as $key)
	{
	$this->userdata[$key] = preg_replace('/(?:\r\n\|[\r\n])/', PHP_EOL, $this->userdata[$key]);
	}
	}

	// Serialize the userdata for the cookie
	$cookie_data = serialize($cookie_data);

	if ($this->sess_encrypt_cookie === TRUE)
	{
	$cookie_data = $this->CI->encryption->encrypt($cookie_data);
	}
	else
	{
	// Require message authentication
	$cookie_data .= hash_hmac('sha1', $cookie_data, $this->encryption_key);
	}

	$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();

	// Set the cookie
	$this->_setcookie($this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain,
	$this->cookie_secure, $this->cookie_httponly);
	}

	// ------------------------------------------------------------------------

	/**
	* Set a cookie with the system
	*
	* This abstraction of the setcookie call allows overriding for unit testing
	*
	* @param string Cookie name
	* @param string Cookie value
	* @param int Expiration time
	* @param string Cookie path
	* @param string Cookie domain
	* @param bool Secure connection flag
	* @param bool HTTP protocol only flag
	* @return void
	*/
	protected function _setcookie($name, $value = '', $expire = 0, $path = '', $domain = '', $secure = FALSE, $httponly = FALSE)
	{
	setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
	}

	// ------------------------------------------------------------------------

	/**
	* Garbage collection
	*
	* This deletes expired session rows from database
	* if the probability percentage is met
	*
	* @return void
	*/
	protected function _sess_gc()
	{
	if ($this->sess_use_database !== TRUE)
	{
	return;
	}

	$probability = ini_get('session.gc_probability');
	$divisor = ini_get('session.gc_divisor');

	if (mt_rand(1, $divisor) <= $probability)
	{
	$expire = $this->now - $this->sess_expiration;
	$this->CI->db->delete($this->sess_table_name, 'last_activity < '.$expire);

	log_message('debug', 'Session garbage collection performed.');
	}
	}

	}

	/* End of file Session_cookie.php */
	/* Location: ./system/libraries/Session/drivers/Session_cookie.php */