File Source for Input.php

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
* Code Igniter
*
* An open source application development framework for PHP 4.3.2 or newer
*
* @package CodeIgniter
* @author Rick Ellis
* @copyright Copyright (c) 2006, pMachine, Inc.
* @license http://www.codeignitor.com/user_guide/license.html
* @link http://www.codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Input Class
*
* Pre-processes global input data for security
*
* @package CodeIgniter
* @subpackage Libraries
* @category Input
* @author Rick Ellis
* @link http://www.codeigniter.com/user_guide/libraries/input.html
*/
class CI_Input {
var $use_xss_clean = FALSE;
var $ip_address = FALSE;
var $user_agent = FALSE;
var $allow_get_array = FALSE;
/**
* Constructor
*
* Sets whether to globally enable the XSS processing
* and whether to allow the $_GET array
*
* @access public
*/
function CI_Input()
{
$CFG =& _load_class('CI_Config');
$this->use_xss_clean = ($CFG->item('global_xss_filtering') === TRUE) ? TRUE : FALSE;
$this->allow_get_array = ($CFG->item('enable_query_strings') === TRUE) ? TRUE : FALSE;
log_message('debug', "Input Class Initialized");
$this->_sanitize_globals();
}
// END CI_Input()
// --------------------------------------------------------------------
/**
* Sanitize Globals
*
* This function does the folowing:
*
* Unsets $_GET data (if query strings are not enabled)
*
* Unsets all globals if register_globals is enabled
*
* Standardizes newline characters to \n
*
* @access private
* @return void
*/
function _sanitize_globals()
{
// Unset globals. This is effectively the same as register_globals = off
foreach (array($_GET, $_POST, $_COOKIE) as $global)
{
if ( ! is_array($global))
{
unset($$global);
}
else
{
foreach ($global as $key => $val)
{
unset($$key);
}
}
}
// Is $_GET data allowed?
if ($this->allow_get_array == FALSE)
{
$_GET = array();
}
// Clean $_POST Data
if (is_array($_POST) AND count($_POST) > 0)
{
foreach($_POST as $key => $val)
{
if (is_array($val))
{
foreach($val as $k => $v)
{
$_POST[$this->_clean_input_keys($key)][$this->_clean_input_keys($k)] = $this->_clean_input_data($v);
}
}
else
{
$_POST[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}
}
// Clean $_COOKIE Data
if (is_array($_COOKIE) AND count($_COOKIE) > 0)
{
foreach($_COOKIE as $key => $val)
{
$_COOKIE[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}
log_message('debug', "Global POST and COOKIE data sanitized");
}
// END _sanitize_globals()
// --------------------------------------------------------------------
/**
* Clean Intput Data
*
* This is a helper function. It escapes data and
* standardizes newline characters to \n
*
* @access private
* @param string
* @return string
*/
function _clean_input_data($str)
{
if (is_array($str))
{
$new_array = array();
foreach ($str as $key => $val)
{
$new_array[$key] = $this->_clean_input_data($val);
}
return $new_array;
}
if ($this->use_xss_clean === TRUE)
{
$str = $this->xss_clean($str);
}
return preg_replace("/\015\012|\015|\012/", "\n", $str);
}
// END _clean_input_data()
// --------------------------------------------------------------------
/**
* Clean Keys
*
* This is a helper function. To prevent malicious users
* from trying to exploit keys we make sure that keys are
* only named with alpha-numeric text and a few other items.
*
* @access private
* @param string
* @return string
*/
function _clean_input_keys($str)
{
if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))
{
exit('Disallowed Key Characters: '.$str);
}
if ( ! get_magic_quotes_gpc())
{
return addslashes($str);
}
return $str;
}
// END _clean_input_keys()
// --------------------------------------------------------------------
/**
* Fetch an item from the POST array
*
* @access public
* @param string
* @return string
*/
function post($index = '', $xss_clean = FALSE)
{
if ( ! isset($_POST[$index]))
{
return FALSE;
}
else
{
if ($xss_clean === TRUE)
{
return $this->xss_clean($_POST[$index]);
}
else
{
return $_POST[$index];
}
}
}
// END post()
// --------------------------------------------------------------------
/**
* Fetch an item from the COOKIE array
*
* @access public
* @param string
* @return string
*/
function cookie($index = '', $xss_clean = FALSE)
{
if ( ! isset($_COOKIE[$index]))
{
return FALSE;
}
else
{
if ($xss_clean === TRUE)
{
return $this->xss_clean($_COOKIE[$index]);
}
else
{
return $_COOKIE[$index];
}
}
}
// END cookie()
// --------------------------------------------------------------------
/**
* Fetch the IP Address
*
* @access public
* @return string
*/
function ip_address()
{
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}
$cip = (isset($_SERVER['HTTP_CLIENT_IP']) AND $_SERVER['HTTP_CLIENT_IP'] != "") ? $_SERVER['HTTP_CLIENT_IP'] : FALSE;
$rip = (isset($_SERVER['REMOTE_ADDR']) AND $_SERVER['REMOTE_ADDR'] != "") ? $_SERVER['REMOTE_ADDR'] : FALSE;
$fip = (isset($_SERVER['HTTP_X_FORWARDED_FOR']) AND $_SERVER['HTTP_X_FORWARDED_FOR'] != "") ? $_SERVER['HTTP_X_FORWARDED_FOR'] : FALSE;
if ($cip && $rip) $this->ip_address = $cip;
elseif ($rip) $this->ip_address = $rip;
elseif ($cip) $this->ip_address = $cip;
elseif ($fip) $this->ip_address = $fip;
if (strstr($this->ip_address, ','))
{
$x = explode(',', $this->ip_address);
$this->ip_address = end($x);
}
if ( ! $this->valid_ip($this->ip_address))
{
$this->ip_address = '0.0.0.0';
}
unset($cip);
unset($rip);
unset($fip);
return $this->ip_address;
}
// END ip_address()
// --------------------------------------------------------------------
/**
* Validate IP Address
*
* @access public
* @param string
* @return string
*/
function valid_ip($ip)
{
return ( ! preg_match( "/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/", $ip)) ? FALSE : TRUE;
}
// END valid_ip()
// --------------------------------------------------------------------
/**
* User Agent
*
* @access public
* @return string
*/
function user_agent()
{
if ($this->user_agent !== FALSE)
{
return $this->user_agent;
}
$this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];
return $this->user_agent;
}
// END user_agent()
// --------------------------------------------------------------------
/**
* XSS Clean
*
* Sanitizes data so that Cross Site Scripting Hacks can be
* prevented.Ê This function does a fair amount of work but
* it is extremely thorough, designed to prevent even the
* most obscure XSS attempts.Ê Nothing is ever 100% foolproof,
* of course, but I haven't been able to get anything passed
* the filter.
*
* Note: This function should only be used to deal with data
* upon submission.Ê It's not something that should
* be used for general runtime processing.
*
* This function was based in part on some code and ideas I
* got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention
*
* To help develop this script I used this great list of
* vulnerabilities along with a few other hacks I've
* harvested from examining vulnerabilities in other programs:
* http://ha.ckers.org/xss.html
*
* @access public
* @param string
* @return string
*/
function xss_clean($str, $charset = 'ISO-8859-1')
{
/*
* Remove Null Characters
*
* This prevents sandwiching null characters
* between ascii characters, like Java\0script.
*
*/
$str = preg_replace('/\0+/', '', $str);
$str = preg_replace('/(\\\\0)+/', '', $str);
/*
* Validate standard character entites
*
* Add a semicolon if missing. We do this to enable
* the conversion of entities to ASCII later.
*
*/
$str = preg_replace('#(&\#*\w+)[\x00-\x20]+;#u',"\\1;",$str);
/*
* Validate UTF16 two byte encodeing (x00)
*
* Just as above, adds a semicolon if missing.
*
*/
$str = preg_replace('#(&\#x*)([0-9A-F]+);*#iu',"\\1\\2;",$str);
/*
* URL Decode
*
* Just in case stuff like this is submitted:
*
* <a href="http://%77%77%77%2E%67%6F%6F%67%6C%65%2E%63%6F%6D">Google</a>
*
* Note: Normally urldecode() would be easier but it removes plus signs
*
*/
$str = preg_replace("/%u0([a-z0-9]{3})/i", "&#x\\1;", $str);
$str = preg_replace("/%([a-z0-9]{2})/i", "&#x\\1;", $str);
/*
* Convert character entities to ASCII
*
* This permits our tests below to work reliably.
* We only convert entities that are within tags since
* these are the ones that will pose security problems.
*
*/
if (preg_match_all("/<(.+?)>/si", $str, $matches))
{
for ($i = 0; $i < count($matches['0']); $i++)
{
$str = str_replace($matches['1'][$i],
$this->_html_entity_decode($matches['1'][$i], $charset),
$str);
}
}
/*
* Convert all tabs to spaces
*
* This prevents strings like this: ja vascript
* Note: we deal with spaces between characters later.
*
*/
$str = preg_replace("#\t+#", " ", $str);
/*
* Makes PHP tags safe
*
* Note: XML tags are inadvertently replaced too:
*
* <?xml
*
* But it doesn't seem to pose a problem.
*
*/
$str = str_replace(array('<?php', '<?PHP', '<?', '?>'), array('<?php', '<?PHP', '<?', '?>'), $str);
/*
* Compact any exploded words
*
* This corrects words like: j a v a s c r i p t
* These words are compacted back to their correct state.
*
*/
$words = array('javascript', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');
foreach ($words as $word)
{
$temp = '';
for ($i = 0; $i < strlen($word); $i++)
{
$temp .= substr($word, $i, 1)."\s*";
}
$temp = substr($temp, 0, -3);
$str = preg_replace('#'.$temp.'#s', $word, $str);
$str = preg_replace('#'.ucfirst($temp).'#s', ucfirst($word), $str);
}
/*
* Remove disallowed Javascript in links or img tags
*/
$str = preg_replace("#<a.+?href=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>.*?</a>#si", "", $str);
$str = preg_replace("#<img.+?src=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>#si", "", $str);
$str = preg_replace("#<(script|xss).*?\>#si", "", $str);
/*
* Remove JavaScript Event Handlers
*
* Note: This code is a little blunt. It removes
* the event handler and anything up to the closing >,
* but it's unlkely to be a problem.
*
*/
$str = preg_replace('#(<[^>]+.*?)(onblur|onchange|onclick|onfocus|onload|onmouseover|onmouseup|onmousedown|onselect|onsubmit|onunload|onkeypress|onkeydown|onkeyup|onresize)[^>]*>#iU',"\\1>",$str);
/*
* Sanitize naughty HTML elements
*
* If a tag containing any of the words in the list
* below is found, the tag gets converted to entities.
*
* So this: <blink>
* Becomes: <blink>
*
*/
$str = preg_replace('#<(/*\s*)(alert|applet|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|layer|link|meta|object|plaintext|style|script|textarea|title|xml|xss)([^>]*)>#is', "<\\1\\2\\3>", $str);
/*
* Sanitize naughty scripting elements
*
* Similar to above, only instead of looking for
* tags it looks for PHP and JavaScript commands
* that are disallowed. Rather than removing the
* code, it simply converts the parenthesis to entities
* rendering the code unexecutable.
*
* For example: eval('some code')
* Becomes: eval('some code')
*
*/
$str = preg_replace('#(alert|cmd|passthru|eval|exec|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)$(.*?)$#si', "\\1\\2(\\3)", $str);
/*
* Final clean up
*
* This adds a bit of extra precaution in case
* something got through the above filters
*
*/
$bad = array(
'document.cookie' => '',
'document.write' => '',
'window.location' => '',
"javascript\s*:" => '',
"Redirect\s+302" => '',
'<!--' => '<!--',
'-->' => '-->'
);
foreach ($bad as $key => $val)
{
$str = preg_replace("#".$key."#i", $val, $str);
}
log_message('debug', "XSS Filtering completed");
return $str;
}
// END xss_clean()
/**
* HTML Entities Decode
*
* This function is a replacement for html_entity_decode()
*
* In some versions of PHP the native function does not work
* when UTF-8 is the specified character set, so this gives us
* a work-around. More info here:
* http://bugs.php.net/bug.php?id=25670
*
* @access private
* @param string
* @param string
* @return string
*/
/* -------------------------------------------------
/* Replacement for html_entity_decode()
/* -------------------------------------------------*/
/*
NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
character set, and the PHP developers said they were not back porting the
fix to versions other than PHP 5.x.
*/
function _html_entity_decode($str, $charset='ISO-8859-1')
{
if (stristr($str, '&') === FALSE) return $str;
// The reason we are not using html_entity_decode() by itself is because
// while it is not technically correct to leave out the semicolon
// at the end of an entity most browsers will still interpret the entity
// correctly. html_entity_decode() does not convert entities without
// semicolons, so we are left with our own little solution here. Bummer.
if (function_exists('html_entity_decode') && (strtolower($charset) != 'utf-8' OR version_compare(phpversion(), '5.0.0', '>=')))
{
$str = html_entity_decode($str,

Source for file Input.php