use_xss_clean = ($CFG->item('global_xss_filtering') === TRUE) ? TRUE : FALSE;
$this->allow_get_array = ($CFG->item('enable_query_strings') === TRUE) ? TRUE : FALSE;
$this->_sanitize_globals();
}
// --------------------------------------------------------------------
/**
* Sanitize Globals
*
* This function does the following:
*
* Unsets $_GET data (if query strings are not enabled)
*
* Unsets all globals if register_globals is enabled
*
* Standardizes newline characters to \n
*
* @access private
* @return void
*/
function _sanitize_globals()
{
// Unset globals for securiy.
// This is effectively the same as register_globals = off
foreach (array($_GET, $_POST, $_COOKIE) as $global)
{
if ( ! is_array($global))
{
global $global;
$$global = NULL;
}
else
{
foreach ($global as $key => $val)
{
global $$key;
$$key = NULL;
}
}
}
// Is $_GET data allowed? If not we'll set the $_GET to an empty array
if ($this->allow_get_array == FALSE)
{
$_GET = array();
}
else
{
if (is_array($_GET) AND count($_GET) > 0)
{
foreach($_GET as $key => $val)
{
$_GET[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
}
}
// Clean $_POST Data
if (is_array($_POST) AND count($_POST) > 0)
{
foreach($_POST as $key => $val)
{
$_POST[$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");
}
// --------------------------------------------------------------------
/**
* Clean Input 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)
{
$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
}
return $new_array;
}
// We strip slashes if magic quotes is on to keep things consistent
if (get_magic_quotes_gpc())
{
$str = stripslashes($str);
}
// Should we filter the input data?
if ($this->use_xss_clean === TRUE)
{
$str = $this->xss_clean($str);
}
// Standardize newlines
return preg_replace("/\015\012|\015|\012/", "\n", $str);
}
// --------------------------------------------------------------------
/**
* Clean Keys
*
* This is a helper function. To prevent malicious users
* from trying to exploit keys we make sure that keys are
* only named with alpha-numeric text and a few other items.
*
* @access private
* @param string
* @return string
*/
function _clean_input_keys($str)
{
if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))
{
exit('Disallowed Key Characters.');
}
return $str;
}
// --------------------------------------------------------------------
/**
* Fetch an item from the GET array
*
* @access public
* @param string
* @param bool
* @return string
*/
function get($index = '', $xss_clean = FALSE)
{
if ( ! isset($_GET[$index]))
{
return FALSE;
}
if ($xss_clean === TRUE)
{
if (is_array($_GET[$index]))
{
foreach($_GET[$index] as $key => $val)
{
$_GET[$index][$key] = $this->xss_clean($val);
}
}
else
{
return $this->xss_clean($_GET[$index]);
}
}
return $_GET[$index];
}
// --------------------------------------------------------------------
/**
* Fetch an item from the POST array
*
* @access public
* @param string
* @param bool
* @return string
*/
function post($index = '', $xss_clean = FALSE)
{
if ( ! isset($_POST[$index]))
{
return FALSE;
}
if ($xss_clean === TRUE)
{
if (is_array($_POST[$index]))
{
foreach($_POST[$index] as $key => $val)
{
$_POST[$index][$key] = $this->xss_clean($val);
}
}
else
{
return $this->xss_clean($_POST[$index]);
}
}
return $_POST[$index];
}
// --------------------------------------------------------------------
/**
* Fetch an item from the COOKIE array
*
* @access public
* @param string
* @param bool
* @return string
*/
function cookie($index = '', $xss_clean = FALSE)
{
if ( ! isset($_COOKIE[$index]))
{
return FALSE;
}
if ($xss_clean === TRUE)
{
if (is_array($_COOKIE[$index]))
{
$cookie = array();
foreach($_COOKIE[$index] as $key => $val)
{
$cookie[$key] = $this->xss_clean($val);
}
return $cookie;
}
else
{
return $this->xss_clean($_COOKIE[$index]);
}
}
else
{
return $_COOKIE[$index];
}
}
// --------------------------------------------------------------------
/**
* Fetch an item from the SERVER array
*
* @access public
* @param string
* @param bool
* @return string
*/
function server($index = '', $xss_clean = FALSE)
{
if ( ! isset($_SERVER[$index]))
{
return FALSE;
}
if ($xss_clean === TRUE)
{
return $this->xss_clean($_SERVER[$index]);
}
return $_SERVER[$index];
}
// --------------------------------------------------------------------
/**
* Fetch the IP Address
*
* @access public
* @return string
*/
function ip_address()
{
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}
if ($this->server('REMOTE_ADDR') AND $this->server('HTTP_CLIENT_IP'))
{
$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
}
elseif ($this->server('REMOTE_ADDR'))
{
$this->ip_address = $_SERVER['REMOTE_ADDR'];
}
elseif ($this->server('HTTP_CLIENT_IP'))
{
$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
}
elseif ($this->server('HTTP_X_FORWARDED_FOR'))
{
$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
}
if ($this->ip_address === FALSE)
{
$this->ip_address = '0.0.0.0';
return $this->ip_address;
}
if (strstr($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';
}
return $this->ip_address;
}
// --------------------------------------------------------------------
/**
* Validate IP Address
*
* @access public
* @param string
* @return string
*/
function valid_ip($ip)
{
if ( ! preg_match( "/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/", $ip))
{
return FALSE;
}
$octets = explode('.', $ip);
for ($i = 1; $i <= 4; $i++)
{
$octet = intval($octets[($i-1)]);
if ($i === 1)
{
if ($octet > 223 OR $octet < 1)
return FALSE;
}
elseif ($i === 4)
{
if ($octet < 1)
return FALSE;
}
else
{
if ($octet > 254)
return FALSE;
}
}
return TRUE;
}
// --------------------------------------------------------------------
/**
* 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 $this->user_agent;
}
// --------------------------------------------------------------------
/**
* XSS Clean
*
* Sanitizes data so that Cross Site Scripting Hacks can be
* prevented. This function does a fair amount of work but
* it is extremely thorough, designed to prevent even the
* most obscure XSS attempts. Nothing is ever 100% foolproof,
* of course, but I haven't been able to get anything passed
* the filter.
*
* Note: This function should only be used to deal with data
* upon submission. It's not something that should
* be used for general runtime processing.
*
* This function was based in part on some code and ideas I
* got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention
*
* To help develop this script I used this great list of
* vulnerabilities along with a few other hacks I've
* harvested from examining vulnerabilities in other programs:
* http://ha.ckers.org/xss.html
*
* @access public
* @param string
* @return string
*/
function xss_clean($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 entities
*
* 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 encoding (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:
*
* Google
*
* Note: Normally urldecode() would be easier but it removes plus signs
*
*/
$str = preg_replace("/(%20)+/", '9u3iovBnRThju941s89rKozm', $str);
$str = preg_replace("/%u0([a-z0-9]{3})/i", "&#x\\1;", $str);
$str = preg_replace("/%([a-z0-9]{2})/i", "&#x\\1;", $str);
$str = str_replace('9u3iovBnRThju941s89rKozm', "%20", $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);
}
}
/*
* Not Allowed Under Any Conditions
*/
$bad = array(
'document.cookie' => '[removed]',
'document.write' => '[removed]',
'window.location' => '[removed]',
"javascript\s*:" => '[removed]',
"Redirect\s+302" => '[removed]',
'' => '-->'
);
foreach ($bad as $key => $val)
{
$str = preg_replace("#".$key."#i", $val, $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:
*
* '), 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*";
}
// We only want to do this when it is followed by a non-word character
// That way valid stuff like "dealer to" does not become "dealerto"
$str = preg_replace('#('.substr($temp, 0, -3).')(\W)#ise', "preg_replace('/\s+/s', '', '\\1').'\\2'", $str);
}
/*
* Remove disallowed Javascript in links or img tags
*/
$str = preg_replace_callback("##si", array($this, '_js_link_removal'), $str);
$str = preg_replace_callback("##si", array($this, '_js_img_removal'), $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 unlikely to be a problem.
*
*/
$event_handlers = array('onblur','onchange','onclick','onfocus','onload','onmouseover','onmouseup','onmousedown','onselect','onsubmit','onunload','onkeypress','onkeydown','onkeyup','onresize', 'xmlns');
$str = preg_replace("#<([^>]+)(".implode('|', $event_handlers).")([^>]*)>#iU", "<\\1\\2\\3>", $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: