Added Session driver with native PHP sessions and original-flavor CI cookie sessions

1 files changed, 583 insertions, 0 deletions

diff --git a/system/libraries/Session/drivers/Session_cookie.php b/system/libraries/Session/drivers/Session_cookie.php
new file mode 100755
index 000000000..0982b1e01
--- /dev/null
+++ b/system/libraries/Session/drivers/Session_cookie.php
@@ -0,0 +1,583 @@
+<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.1.6 or newer
+ *
+ * @package		CodeIgniter
+ * @author		ExpressionEngine Dev Team
+ * @copyright	Copyright (c) 2008 - 2010, EllisLab, Inc.
+ * @license		http://codeigniter.com/user_guide/license.html
+ * @link		http://codeigniter.com
+ * @since		Version 2.0
+ * @filesource
+ */
+
+
+/**
+ * Cookie-based session management driver
+ *
+ * This is the CI_Session functionality, as written by EllisLab, abstracted out to a driver.
+ * I have done a little updating for PHP5, and made minor changes to extract this functionality from
+ * the public interface (now in the Session Library), but effectively this code is unchanged.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Libraries
+ * @category	Sessions
+ * @author		ExpressionEngine Dev Team and Darren Hill (DChill42)
+ */
+class Session_Cookie extends SessionDriver {
+	private $sess_encrypt_cookie	= FALSE;
+	private $sess_use_database		= FALSE;
+	private $sess_table_name		= '';
+	private $sess_expiration		= 7200;
+	private $sess_expire_on_close	= FALSE;
+	private $sess_match_ip			= FALSE;
+	private $sess_match_useragent	= TRUE;
+	private $sess_cookie_name		= 'ci_session';
+	private $cookie_prefix			= '';
+	private $cookie_path			= '';
+	private $cookie_domain			= '';
+	private $sess_time_to_update	= 300;
+	private $encryption_key		 	= '';
+	private $time_reference		 	= 'time';
+	private $userdata				= array();
+	private $CI					 	= null;
+	private $now					= 0;
+
+	const gc_probability			= 5;
+
+	/**
+	 * Initialize session driver object
+	 *
+	 * @access	protected
+	 * @return	void
+	 */
+	protected function initialize()
+	{
+		// Set the super object to a local variable for use throughout the class
+		$this->CI =& get_instance();
+
+		// Set all the session preferences, which can either be set
+		// manually via the $params array above or via the config file
+		foreach (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', 'sess_time_to_update', 'time_reference', 'cookie_prefix', 'encryption_key') as $key)
+		{
+			$this->$key = (isset($this->parent->params[$key])) ? $this->parent->params[$key] : $this->CI->config->item($key);
+		}
+
+		if ($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.');
+		}
+
+		// Load the string helper so we can use the strip_slashes() function
+		$this->CI->load->helper('string');
+
+		// Do we need encryption? If so, load the encryption class
+		if ($this->sess_encrypt_cookie == TRUE)
+		{
+			$this->CI->load->library('encrypt');
+		}
+
+		// Are we using a database? If so, load it
+		if ($this->sess_use_database === TRUE && $this->sess_table_name != '')
+		{
+			$this->CI->load->database();
+		}
+
+		// 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
+		$this->_sess_gc();
+	}
+
+	/**
+	 * Write the session data
+	 *
+	 * @return	void
+	 */
+	public function sess_save()
+	{
+		// Are we saving custom data to the DB? If not, all we do is update the cookie
+		if ($this->sess_use_database === FALSE)
+		{
+			$this->_set_cookie();
+			return;
+		}
+
+		// set the custom userdata, the session data we will set in a second
+		$custom_userdata = $this->all_userdata();
+		$cookie_userdata = array();
+
+		// Before continuing, we need to determine if there is any custom data to deal with.
+		// Let's determine this by removing the default indexes to see if there's anything left in the array
+		// and set the session data while we're at it
+		foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
+		{
+			unset($custom_userdata[$val]);
+			$cookie_userdata[$val] = $this->userdata($val);
+		}
+
+		// Did we find any custom data? If not, we turn the empty array into a string
+		// since there's no reason to serialize and store an empty array in the DB
+		if (count($custom_userdata) === 0)
+		{
+			$custom_userdata = '';
+		}
+		else
+		{
+			// Serialize the custom data array so we can store it
+			$custom_userdata = $this->_serialize($custom_userdata);
+		}
+
+		// Run the update query
+		$this->CI->db->where('session_id', $this->userdata('session_id'));
+		$this->CI->db->update($this->sess_table_name,
+			array('last_activity' => $this->userdata('last_activity'), 'user_data' => $custom_userdata));
+
+		// Write the cookie. Notice that we manually pass the cookie data array to the
+		// _set_cookie() function. Normally that function will store $this->userdata, but
+		// in this case that array contains custom data, which we do not want in the cookie.
+		$this->_set_cookie($cookie_userdata);
+	}
+
+	/**
+	 * Destroy the current session
+	 *
+	 * @return	void
+	 */
+	public function sess_destroy()
+	{
+		// Kill the session DB row
+		if ($this->sess_use_database === TRUE && $this->has_userdata('session_id'))
+		{
+			$this->CI->db->where('session_id', $this->userdata['session_id']);
+			$this->CI->db->delete($this->sess_table_name);
+		}
+
+		// Kill the cookie
+		setcookie($this->sess_cookie_name, addslashes(serialize(array())), ($this->now - 31500000),
+			$this->cookie_path, $this->cookie_domain, 0);
+	}
+
+	/**
+	 * Regenerate the current session
+	 *
+	 * Regenerate the session id
+	 *
+	 * @param	boolean	Destroy session data flag (default: false)
+	 * @return	void
+	 */
+	public function sess_regenerate($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 reference to array
+		return $this->userdata;
+	}
+
+	/**
+	 * Fetch the current session data if it exists
+	 *
+	 * @access	private
+	 * @return	bool
+	 */
+	private function _sess_read()
+	{
+		// Fetch the cookie
+		$session = $this->CI->input->cookie($this->sess_cookie_name);
+
+		// No cookie? Goodbye cruel world!...
+		if ($session === FALSE)
+		{
+			log_message('debug', 'A session cookie was not found.');
+			return FALSE;
+		}
+
+		// Decrypt the cookie data
+		if ($this->sess_encrypt_cookie == TRUE)
+		{
+			$session = $this->CI->encrypt->decode($session);
+		}
+		else
+		{
+			// encryption was not used, so we need to check the md5 hash
+			$hash	= substr($session, strlen($session)-32); // get last 32 chars
+			$session = substr($session, 0, strlen($session)-32);
+
+			// Does the md5 hash match? This is to prevent manipulation of session data in userspace
+			if ($hash !== md5($session.$this->encryption_key))
+			{
+				log_message('error', 'The session cookie data did not match what was expected. '.
+					'This could be a possible hacking attempt.');
+				$this->sess_destroy();
+				return FALSE;
+			}
+		}
+
+		// Unserialize the session array
+		$session = $this->_unserialize($session);
+
+		// Is the session data we unserialized an array with the correct format?
+		if ( ! is_array($session) || ! isset($session['session_id']) || ! isset($session['ip_address']) ||
+		! isset($session['user_agent']) || ! isset($session['last_activity']))
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Is the session current?
+		if (($session['last_activity'] + $this->sess_expiration) < $this->now())
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Does the IP Match?
+		if ($this->sess_match_ip == TRUE && $session['ip_address'] != $this->CI->input->ip_address())
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Does the User Agent Match?
+		if ($this->sess_match_useragent == TRUE &&
+		trim($session['user_agent']) != trim(substr($this->CI->input->user_agent(), 0, 50)))
+		{
+			$this->sess_destroy();
+			return FALSE;
+		}
+
+		// Is there a corresponding session in the DB?
+		if ($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']);
+			}
+
+			$query = $this->CI->db->get($this->sess_table_name);
+
+			// No result? Kill it!
+			if ($query->num_rows() == 0)
+			{
+				$this->sess_destroy();
+				return FALSE;
+			}
+
+			// Is there custom data? If so, add it to the main session array
+			$row = $query->row();
+			if (isset($row->user_data) && $row->user_data != '')
+			{
+				$custom_data = $this->_unserialize($row->user_data);
+
+				if (is_array($custom_data))
+				{
+					foreach ($custom_data as $key => $val)
+					{
+						$session[$key] = $val;
+					}
+				}
+			}
+		}
+
+		// Session is valid!
+		$this->userdata = $session;
+		unset($session);
+
+		return TRUE;
+	}
+
+	/**
+	 * Create a new session
+	 *
+	 * @access	private
+	 * @return	void
+	 */
+	private function _sess_create()
+	{
+		$sessid = '';
+		while (strlen($sessid) < 32)
+		{
+			$sessid .= mt_rand(0, mt_getrandmax());
+		}
+
+		// To make the session ID even more secure we'll combine it with the user's IP
+		$sessid .= $this->CI->input->ip_address();
+
+		$this->set_userdata('session_id', md5(uniqid($sessid, TRUE)));
+		$this->set_userdata('ip_address', $this->CI->input->ip_address());
+		$this->set_userdata('user_agent', substr($this->CI->input->user_agent(), 0, 50));
+		$this->set_userdata('last_activity',$this->now());
+
+
+		// Save the data to the DB if needed
+		if ($this->sess_use_database === TRUE)
+		{
+			$this->CI->db->query($this->CI->db->insert_string($this->sess_table_name, $this->all_userdata()));
+		}
+
+		// Write the cookie
+		$this->_set_cookie();
+	}
+
+	/**
+	 * Update an existing session
+	 *
+	 * @access	private
+	 * @param	boolean	Force update flag (default: false)
+	 * @return	void
+	 */
+	private function _sess_update($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;
+		}
+
+		// Save the old session id so we know which record to
+		// update in the database if we need it
+		$old_sessid = $this->userdata['session_id'];
+		$new_sessid = '';
+		while (strlen($new_sessid) < 32)
+		{
+			$new_sessid .= mt_rand(0, mt_getrandmax());
+		}
+
+		// 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
+		$new_sessid = md5(uniqid($new_sessid, TRUE));
+
+		// Update the session data in the session data array
+		$this->set_userdata('session_id', $new_sessid);
+		$this->set_userdata('last_activity', $this->now());
+
+		// _set_cookie() will handle this for us if we aren't using database sessions
+		// by pushing all userdata to the cookie.
+		$cookie_data = NULL;
+
+		// Update the session ID and last_activity field in the DB if needed
+		if ($this->sess_use_database === TRUE)
+		{
+			// set cookie explicitly to only have our session data
+			$cookie_data = array();
+			foreach (array('session_id','ip_address','user_agent','last_activity') as $val)
+			{
+				$cookie_data[$val] = $this->userdata[$val];
+			}
+
+			$this->CI->db->query($this->CI->db->update_string($this->sess_table_name,
+				array('last_activity' => $this->now(), 'session_id' => $new_sessid),
+				array('session_id' => $old_sessid)));
+		}
+
+		// Write the cookie
+		$this->_set_cookie($cookie_data);
+	}
+
+	/**
+	 * Get the "now" time
+	 *
+	 * @access	private
+	 * @return	int
+	 */
+	private function _get_time()
+	{
+		if (strtolower($this->time_reference) == 'gmt')
+		{
+			$now = time();
+			$time = mktime(gmdate('H', $now), gmdate('i', $now), gmdate('s', $now), gmdate('m', $now),
+				gmdate('d', $now), gmdate('Y', $now));
+		}
+		else
+		{
+			$time = time();
+		}
+
+		return $time;
+	}
+
+	/**
+	 * Write the session cookie
+	 *
+	 * @access	private
+	 * @param	array	Cookie name/value pairs
+	 * @return	void
+	 */
+	private function _set_cookie(array $cookie_data = NULL)
+	{
+		if (is_null($cookie_data))
+		{
+			$cookie_data = $this->all_userdata();
+		}
+
+		// Serialize the userdata for the cookie
+		$cookie_data = $this->_serialize($cookie_data);
+
+		if ($this->sess_encrypt_cookie == TRUE)
+		{
+			$cookie_data = $this->CI->encrypt->encode($cookie_data);
+		}
+		else
+		{
+			// if encryption is not used, we provide an md5 hash to prevent userside tampering
+			$cookie_data = $cookie_data.md5($cookie_data.$this->encryption_key);
+		}
+
+		$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();
+
+		// Set the cookie
+		setcookie($this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain, 0);
+	}
+
+	/**
+	 * Serialize an array
+	 *
+	 * This function first converts any slashes found in the array to a temporary
+	 * marker, so when it gets unserialized the slashes will be preserved
+	 *
+	 * @access	private
+	 * @param	mixed	Data to serialize
+	 * @return	string
+	 */
+	private function _serialize($data)
+	{
+		if (is_array($data))
+		{
+			foreach ($data as $key => $val)
+			{
+				if (is_string($val))
+				{
+					$data[$key] = str_replace('\\', '{{slash}}', $val);
+				}
+			}
+		}
+		else
+		{
+			if (is_string($data))
+			{
+				$data = str_replace('\\', '{{slash}}', $data);
+			}
+		}
+
+		return serialize($data);
+	}
+
+	/**
+	 * Unserialize
+	 *
+	 * This function unserializes a data string, then converts any
+	 * temporary slash markers back to actual slashes
+	 *
+	 * @access	private
+	 * @param	string	Data to unserialize
+	 * @return	mixed
+	 */
+	private function _unserialize($data)
+	{
+		$data = @unserialize(strip_slashes($data));
+
+		if (is_array($data))
+		{
+			foreach ($data as $key => $val)
+			{
+				if (is_string($val))
+				{
+					$data[$key] = str_replace('{{slash}}', '\\', $val);
+				}
+			}
+
+			return $data;
+		}
+
+		return (is_string($data)) ? str_replace('{{slash}}', '\\', $data) : $data;
+	}
+
+	/**
+	 * Garbage collection
+	 *
+	 * This deletes expired session rows from database
+	 * if the probability percentage is met
+	 *
+	 * @access	private
+	 * @return	void
+	 */
+	private function _sess_gc()
+	{
+		if ($this->sess_use_database != TRUE)
+		{
+			return;
+		}
+
+		srand(time());
+		if ((rand() % 100) < self::gc_probability)
+		{
+			$expire = $this->now() - $this->sess_expiration;
+
+			$this->CI->db->where('last_activity < '.$expire);
+			$this->CI->db->delete($this->sess_table_name);
+
+			log_message('debug', 'Session garbage collection performed.');
+		}
+	}
+}
+// END Session_Cookie Class
+
+/* End of file Session_cookie.php */
+/* Location: ./system/libraries/Session/Session.php */
+?>