1 files changed, 82 insertions, 25 deletions

diff --git a/system/libraries/Session/Session.php b/system/libraries/Session/Session.php
index 3b391a8ef..3e4865cd1 100644
--- a/system/libraries/Session/Session.php
+++ b/system/libraries/Session/Session.php
@@ -6,7 +6,7 @@
  *
  * This content is released under the MIT License (MIT)
  *
- * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
+ * Copyright (c) 2014 - 2017, 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
@@ -29,7 +29,7 @@
  * @package	CodeIgniter
  * @author	EllisLab Dev Team
  * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
- * @copyright	Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
+ * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
  * @license	http://opensource.org/licenses/MIT	MIT License
  * @link	https://codeigniter.com
  * @since	Version 2.0.0
@@ -57,6 +57,7 @@ class CI_Session {
 
 	protected $_driver = 'files';
 	protected $_config;
+	protected $_sid_regexp;
 
 	// ------------------------------------------------------------------------
 
@@ -99,27 +100,12 @@ class CI_Session {
 
 		// Configuration ...
 		$this->_configure($params);
+		$this->_config['_sid_regexp'] = $this->_sid_regexp;
 
 		$class = new $class($this->_config);
 		if ($class instanceof SessionHandlerInterface)
 		{
-			if (is_php('5.4'))
-			{
-				session_set_save_handler($class, TRUE);
-			}
-			else
-			{
-				session_set_save_handler(
-					array($class, 'open'),
-					array($class, 'close'),
-					array($class, 'read'),
-					array($class, 'write'),
-					array($class, 'destroy'),
-					array($class, 'gc')
-				);
-
-				register_shutdown_function('session_write_close');
-			}
+			session_set_save_handler($class, TRUE);
 		}
 		else
 		{
@@ -131,7 +117,7 @@ class CI_Session {
 		if (isset($_COOKIE[$this->_config['cookie_name']])
 			&& (
 				! is_string($_COOKIE[$this->_config['cookie_name']])
-				OR ! preg_match('/^[0-9a-f]{40}$/', $_COOKIE[$this->_config['cookie_name']])
+				OR ! preg_match('#\A'.$this->_sid_regexp.'\z#', $_COOKIE[$this->_config['cookie_name']])
 			)
 		)
 		{
@@ -188,9 +174,6 @@ class CI_Session {
 	 */
 	protected function _ci_load_classes($driver)
 	{
-		// PHP 5.4 compatibility
-		interface_exists('SessionHandlerInterface', FALSE) OR require_once(BASEPATH.'libraries/Session/SessionHandlerInterface.php');
-
 		$prefix = config_item('subclass_prefix');
 
 		if ( ! class_exists('CI_Session_driver', FALSE))
@@ -315,8 +298,82 @@ class CI_Session {
 		ini_set('session.use_strict_mode', 1);
 		ini_set('session.use_cookies', 1);
 		ini_set('session.use_only_cookies', 1);
-		ini_set('session.hash_function', 1);
-		ini_set('session.hash_bits_per_character', 4);
+
+		$this->_configure_sid_length();
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
+	 * Configure session ID length
+	 *
+	 * To make life easier, we used to force SHA-1 and 4 bits per
+	 * character on everyone. And of course, someone was unhappy.
+	 *
+	 * Then PHP 7.1 broke backwards-compatibility because ext/session
+	 * is such a mess that nobody wants to touch it with a pole stick,
+	 * and the one guy who does, nobody has the energy to argue with.
+	 *
+	 * So we were forced to make changes, and OF COURSE something was
+	 * going to break and now we have this pile of shit. -- Narf
+	 *
+	 * @return	void
+	 */
+	protected function _configure_sid_length()
+	{
+		if (PHP_VERSION_ID < 70100)
+		{
+			$hash_function = ini_get('session.hash_function');
+			if (ctype_digit($hash_function))
+			{
+				if ($hash_function !== '1')
+				{
+					ini_set('session.hash_function', 1);
+				}
+
+				$bits = 160;
+			}
+			elseif ( ! in_array($hash_function, hash_algos(), TRUE))
+			{
+				ini_set('session.hash_function', 1);
+				$bits = 160;
+			}
+			elseif (($bits = strlen(hash($hash_function, 'dummy', false)) * 4) < 160)
+			{
+				ini_set('session.hash_function', 1);
+				$bits = 160;
+			}
+
+			$bits_per_character = (int) ini_get('session.hash_bits_per_character');
+			$sid_length         = (int) ceil($bits / $bits_per_character);
+		}
+		else
+		{
+			$bits_per_character = (int) ini_get('session.sid_bits_per_character');
+			$sid_length         = (int) ini_get('session.sid_length');
+			if (($bits = $sid_length * $bits_per_character) < 160)
+			{
+				// Add as many more characters as necessary to reach at least 160 bits
+				$sid_length += (int) ceil((160 % $bits) / $bits_per_character);
+				ini_set('session.sid_length', $sid_length);
+			}
+		}
+
+		// Yes, 4,5,6 are the only known possible values as of 2016-10-27
+		switch ($bits_per_character)
+		{
+			case 4:
+				$this->_sid_regexp = '[0-9a-f]';
+				break;
+			case 5:
+				$this->_sid_regexp = '[0-9a-v]';
+				break;
+			case 6:
+				$this->_sid_regexp = '[0-9a-zA-Z,-]';
+				break;
+		}
+
+		$this->_sid_regexp .= '{'.$sid_length.'}';
 	}
 
 	// ------------------------------------------------------------------------