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<?php
/**
* Elgg session management
* Functions to manage logins
*
* @package Elgg
* @subpackage Core
* @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html GNU Public License version 2
* @author Curverider Ltd
* @copyright Curverider Ltd 2008
* @link http://elgg.org/
*/
/** Elgg magic session */
global $SESSION;
/**
* Magic session class.
* This class is intended to extend the $_SESSION magic variable by providing an API hook
* to plug in other values.
*
* Primarily this is intended to provide a way of supplying "logged in user" details without touching the session
* (which can cause problems when accessed server side).
*
* If a value is present in the session then that value is returned, otherwise a plugin hook 'session:get', '$var' is called,
* where $var is the variable being requested.
*
* Setting values will store variables in the session in the normal way.
*
* LIMITATIONS: You can not access multidimensional arrays
*
* This is EXPERIMENTAL.
*/
class ElggSession implements ArrayAccess
{
/** Local cache of trigger retrieved variables */
private static $__localcache;
function __isset($key) { return $this->offsetExists($key); }
/** Set a value, go straight to session. */
function offsetSet($key, $value) { $_SESSION[$key] = $value; }
/**
* Get a variable from either the session, or if its not in the session attempt to get it from
* an api call.
*/
function offsetGet($key)
{
if (!ElggSession::$__localcache)
ElggSession::$__localcache = array();
if (isset($_SESSION[$key]))
return $_SESSION[$key];
if (isset(ElggSession::$__localcache[$key]))
return ElggSession::$__localcache[$key];
$value = null;
$value = trigger_plugin_hook('session:get', $key, null, $value);
ElggSession::$__localcache[$key] = $value;
return ElggSession::$__localcache[$key];
}
/**
* Unset a value from the cache and the session.
*/
function offsetUnset($key)
{
unset(ElggSession::$__localcache[$key]);
unset($_SESSION[$key]);
}
/**
* Return whether the value is set in either the session or the cache.
*/
function offsetExists($offset) {
if (isset(ElggSession::$__localcache[$offset]))
return true;
if (isset($_SESSION[$offset]))
return true;
if ($this->offsetGet($offset)) return true;
}
}
/**
* Return the current logged in user, or null if no user is logged in.
*
* If no user can be found in the current session, a plugin hook - 'session:get' 'user' to give plugin
* authors another way to provide user details to the ACL system without touching the session.
*/
function get_loggedin_user()
{
global $SESSION;
return $SESSION['user'];
}
/**
* Return the current logged in user by id.
*
* @see get_loggedin_user()
* @return int
*/
function get_loggedin_userid()
{
$user = get_loggedin_user();
if ($user)
return $user->guid;
return 0;
}
/**
* Returns whether or not the user is currently logged in
*
* @return true|false
*/
function isloggedin() {
if (!is_installed()) return false;
$user = get_loggedin_user();
if ((isset($user)) && ($user->guid > 0))
return true;
return false;
}
/**
* Returns whether or not the user is currently logged in and that they are an admin user.
*
* @uses isloggedin()
* @return true|false
*/
function isadminloggedin()
{
if (!is_installed()) return false;
$user = get_loggedin_user();
if ((isloggedin()) && (($user->admin || $user->siteadmin)))
return true;
return false;
}
/**
* Perform standard authentication with a given username and password.
* Returns an ElggUser object for use with login.
*
* @see login
* @param string $username The username, optionally (for standard logins)
* @param string $password The password, optionally (for standard logins)
* @return ElggUser|false The authenticated user object, or false on failure.
*/
function authenticate($username, $password) {
if (pam_authenticate(array('username' => $username, 'password' => $password)))
return get_user_by_username($username);
return false;
}
/**
* Hook into the PAM system which accepts a username and password and attempts to authenticate
* it against a known user.
*
* @param array $credentials Associated array of credentials passed to pam_authenticate. This function expects
* 'username' and 'password' (cleartext).
*/
function pam_auth_userpass($credentials = NULL)
{
if (is_array($credentials) && ($credentials['username']) && ($credentials['password']))
{
//$dbpassword = md5($credentials['password']);
if ($user = get_user_by_username($credentials['username'])) {
// Let admins log in without validating their email, but normal users must have validated their email
if ((!$user->admin) && (!$user->validated) && (!$user->admin_created))
return false;
if ($user->password == generate_user_password($user, $credentials['password'])) {
return true;
}
}
}
return false;
}
/**
* Logs in a specified ElggUser. For standard registration, use in conjunction
* with authenticate.
*
* @see authenticate
* @param ElggUser $user A valid Elgg user object
* @param boolean $persistent Should this be a persistent login?
* @return true|false Whether login was successful
*/
function login(ElggUser $user, $persistent = false) {
global $CONFIG;
$_SESSION['user'] = $user;
$_SESSION['guid'] = $user->getGUID();
$_SESSION['id'] = $_SESSION['guid'];
$_SESSION['username'] = $user->username;
$_SESSION['name'] = $user->name;
$code = (md5($user->name . $user->username . time() . rand()));
$user->code = md5($code);
$_SESSION['code'] = $code;
if (($persistent))
setcookie("elggperm", $code, (time()+(86400 * 30)),"/");
if (!$user->save() || !trigger_elgg_event('login','user',$user)) {
unset($_SESSION['username']);
unset($_SESSION['name']);
unset($_SESSION['code']);
unset($_SESSION['guid']);
unset($_SESSION['id']);
unset($_SESSION['user']);
setcookie("elggperm", "", (time()-(86400 * 30)),"/");
return false;
}
// Users privilege has been elevated, so change the session id (help prevent session hijacking)
session_regenerate_id();
// Update statistics
set_last_login($_SESSION['guid']);
return true;
}
/**
* Log the current user out
*
* @return true|false
*/
function logout() {
global $CONFIG;
if (isset($_SESSION['user'])) {
if (!trigger_elgg_event('logout','user',$_SESSION['user'])) return false;
$_SESSION['user']->code = "";
$_SESSION['user']->save();
}
unset($_SESSION['username']);
unset($_SESSION['name']);
unset($_SESSION['code']);
unset($_SESSION['guid']);
unset($_SESSION['id']);
unset($_SESSION['user']);
setcookie("elggperm", "", (time()-(86400 * 30)),"/");
session_destroy();
return true;
}
function get_session_fingerprint()
{
global $CONFIG;
return md5($_SERVER['HTTP_USER_AGENT'] . get_site_secret());
}
/**
* Initialises the system session and potentially logs the user in
*
* This function looks for:
*
* 1. $_SESSION['id'] - if not present, we're logged out, and this is set to 0
* 2. The cookie 'elggperm' - if present, checks it for an authentication token, validates it, and potentially logs the user in
*
* @uses $_SESSION
* @param unknown_type $event
* @param unknown_type $object_type
* @param unknown_type $object
*/
function session_init($event, $object_type, $object) {
global $DB_PREFIX, $CONFIG;
if (!is_db_installed()) return false;
// Use database for sessions
$DB_PREFIX = $CONFIG->dbprefix; // HACK to allow access to prefix after object distruction
session_set_save_handler("__elgg_session_open", "__elgg_session_close", "__elgg_session_read", "__elgg_session_write", "__elgg_session_destroy", "__elgg_session_gc");
session_name('Elgg');
session_start();
// Do some sanity checking by generating a fingerprint (makes some XSS attacks harder)
if (isset($_SESSION['__elgg_fingerprint']))
{
if ($_SESSION['__elgg_fingerprint'] != get_session_fingerprint())
{
session_destroy();
return false;
}
}
else
{
$_SESSION['__elgg_fingerprint'] = get_session_fingerprint();
}
// Generate a simple token
if (!isset($_SESSION['__elgg_session'])) $_SESSION['__elgg_session'] = md5(microtime().rand());
if (empty($_SESSION['guid'])) {
if (isset($_COOKIE['elggperm'])) {
$code = $_COOKIE['elggperm'];
$code = md5($code);
unset($_SESSION['guid']);//$_SESSION['guid'] = 0;
unset($_SESSION['id']);//$_SESSION['id'] = 0;
if ($user = get_user_by_code($code)) {
$_SESSION['user'] = $user;
$_SESSION['id'] = $user->getGUID();
$_SESSION['guid'] = $_SESSION['id'];
$_SESSION['code'] = $_COOKIE['elggperm'];
}
} else {
unset($_SESSION['id']); //$_SESSION['id'] = 0;
unset($_SESSION['guid']);//$_SESSION['guid'] = 0;
unset($_SESSION['code']);//$_SESSION['code'] = "";
}
} else {
if (!empty($_SESSION['code'])) {
$code = md5($_SESSION['code']);
if ($user = get_user_by_code($code)) {
$_SESSION['user'] = $user;
$_SESSION['id'] = $user->getGUID();
$_SESSION['guid'] = $_SESSION['id'];
} else {
unset($_SESSION['user']);
unset($_SESSION['id']); //$_SESSION['id'] = 0;
unset($_SESSION['guid']);//$_SESSION['guid'] = 0;
unset($_SESSION['code']);//$_SESSION['code'] = "";
}
} else {
//$_SESSION['user'] = new ElggDummy();
unset($_SESSION['id']); //$_SESSION['id'] = 0;
unset($_SESSION['guid']);//$_SESSION['guid'] = 0;
unset($_SESSION['code']);//$_SESSION['code'] = "";
}
}
if ($_SESSION['id'] > 0) {
set_last_action($_SESSION['id']);
}
register_action("login",true);
register_action("logout");
// Register a default PAM handler
register_pam_handler('pam_auth_userpass');
// Initialise the magic session
global $SESSION;
$SESSION = new ElggSession();
return true;
}
/**
* Used at the top of a page to mark it as logged in users only.
*
*/
function gatekeeper() {
if (!isloggedin()) {
$_SESSION['last_forward_from'] = current_page_url();
forward();
}
}
/**
* Used at the top of a page to mark it as logged in admin or siteadmin only.
*
*/
function admin_gatekeeper()
{
gatekeeper();
if (!isadminloggedin()) {
$_SESSION['last_forward_from'] = current_page_url();
forward();
}
}
/**
* DB Based session handling code.
*/
function __elgg_session_open($save_path, $session_name)
{
global $sess_save_path;
$sess_save_path = $save_path;
return true;
}
/**
* DB Based session handling code.
*/
function __elgg_session_close()
{
return true;
}
/**
* DB Based session handling code.
*/
function __elgg_session_read($id)
{
global $DB_PREFIX;
$id = sanitise_string($id);
try {
$result = get_data_row("SELECT * from {$DB_PREFIX}users_sessions where session='$id'");
if ($result)
return (string)$result->data;
} catch (DatabaseException $e) {
// Fall back to file store in this case, since this likely means that the database hasn't been upgraded
global $sess_save_path;
$sess_file = "$sess_save_path/sess_$id";
return (string) @file_get_contents($sess_file);
}
return '';
}
/**
* DB Based session handling code.
*/
function __elgg_session_write($id, $sess_data)
{
global $DB_PREFIX;
$id = sanitise_string($id);
$time = time();
try {
$sess_data_sanitised = sanitise_string($sess_data);
if (insert_data("REPLACE INTO {$DB_PREFIX}users_sessions (session, ts, data) VALUES ('$id', '$time', '$sess_data_sanitised')")!==false)
return true;
} catch (DatabaseException $e) {
// Fall back to file store in this case, since this likely means that the database hasn't been upgraded
global $sess_save_path;
$sess_file = "$sess_save_path/sess_$id";
if ($fp = @fopen($sess_file, "w")) {
$return = fwrite($fp, $sess_data);
fclose($fp);
return $return;
}
else
error_log('marcus FAILED TO WRITe ' . print_r($CONFIG, true));
}
return false;
}
/**
* DB Based session handling code.
*/
function __elgg_session_destroy($id)
{
global $DB_PREFIX;
$id = sanitise_string($id);
try {
return (bool)delete_data("DELETE from {$DB_PREFIX}users_sessions where session='$id'");
} catch (DatabaseException $e) {
// Fall back to file store in this case, since this likely means that the database hasn't been upgraded
global $sess_save_path;
$sess_file = "$sess_save_path/sess_$id";
return(@unlink($sess_file));
}
return false;
}
/**
* DB Based session handling code.
*/
function __elgg_session_gc($maxlifetime)
{
global $DB_PREFIX;
$life = time()-$maxlifetime;
try {
return (bool)delete_data("DELETE from {$DB_PREFIX}users_sessions where ts<'$life'");
} catch (DatabaseException $e) {
// Fall back to file store in this case, since this likely means that the database hasn't been upgraded
global $sess_save_path;
foreach (glob("$sess_save_path/sess_*") as $filename) {
if (filemtime($filename) < $life) {
@unlink($filename);
}
}
}
return true;
}
register_elgg_event_handler("boot","system","session_init",1);
?>
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