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www.giggi.me / code-igniter-v3-giggi / 5583e1aae64ff7e902136c4ba610d438dc2015d4 / . / system / libraries / Input.php
blob: 9d64a2cb42b5edda10a26e4763f653c7283967e7 [file] [log] [blame]
<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 4.3.2 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2006, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
/**
* Input Class
*
* Pre-processes global input data for security
*
* @package CodeIgniter
* @subpackage Libraries
* @category Input
* @author ExpressionEngine Dev Team
* @link http://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()
{
log_message('debug', "Input Class Initialized");
$CFG =& load_class('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;
$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()
{
// Would kind of be "wrong" to unset any of these GLOBALS
$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST', '_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
'system_folder', 'application_folder', 'BM', 'EXT', 'CFG', 'URI', 'RTR', 'OUT', 'IN');
// Unset globals for security.
// This is effectively the same as register_globals = off
foreach (array($_GET, $_POST, $_COOKIE, $_SERVER, $_FILES, $_ENV, (isset($_SESSION) && is_array($_SESSION)) ? $_SESSION : array()) as $global)
{
if (! is_array($global))
{
if (! in_array($global, $protected))
{
unset($GLOBALS[$global]);
}
}
else
{
foreach ($global as $key => $val)
{
if (! in_array($key, $protected))
{
unset($GLOBALS[$key]);
}
if (is_array($val))
{
foreach($val as $k => $v)
{
if (! in_array($k, $protected))
{
unset($GLOBALS[$k]);
}
}
}
}
}
}
// 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 $this->ip_address;
}
// --------------------------------------------------------------------
/**
* Validate IP Address
*
* Updated version suggested by Geert De Deckere
*
* @access public
* @param string
* @return string
*/
function valid_ip($ip)
{
$ip_segments = explode('.', $ip);
// Always 4 segments needed
if (count($ip_segments) != 4)
{
return FALSE;
}
// IP can not start with 0
if (substr($ip_segments[0], 0, 1) == '0')
{
return FALSE;
}
// Check each segment
foreach ($ip_segments as $segment)
{
// IP segments must be digits and can not be
// longer than 3 digits or greater then 255
if (preg_match("/[^0-9]/", $segment) OR $segment > 255 OR strlen($segment) > 3)
{
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 $this->user_agent;
}
// --------------------------------------------------------------------
/**
* Filename Security
*
* @access public
* @param string
* @return string
*/
function filename_security($str)
{
$bad = array(
"../",
"./",
"<!--",
"-->",
"<",
">",
"'",
'"',
'&',
'$',
'#',
'{',
'}',
'[',
']',
'=',
';',
'?',
"%20",
"%22",
"%3c", // <
"%253c", // <
"%3e", // >
"%0e", // >
"%28", // (
"%29", // )
"%2528", // (
"%26", // &
"%24", // $
"%3f", // ?
"%3b", // ;
"%3d" // =
);
return stripslashes(str_replace($bad, '', $str));
}
// --------------------------------------------------------------------
/**
* XSS Clean
*
* Sanitizes data so that Cross Site Scripting Hacks can be
* prevented.  This function does a fair amount of work but
* it is extremely thorough, designed to prevent even the
* most obscure XSS attempts.  Nothing is ever 100% foolproof,
* of course, but I haven't been able to get anything passed
* the filter.
*
* Note: This function should only be used to deal with data
* upon submission.  It's not something that should
* be used for general runtime processing.
*
* This function was based in part on some code and ideas I
* got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention
*
* To help develop this script I used this great list of
* vulnerabilities along with a few other hacks I've
* harvested from examining vulnerabilities in other programs:
* http://ha.ckers.org/xss.html
*
* @access public
* @param string
* @return string
*/
function xss_clean($str)
{
/*
* 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('#(&\#?[0-9a-z]+)[\x00-\x20]*;?#i', "\\1;", $str);
/*
* Validate UTF16 two byte encoding (x00)
*
* Just as above, adds a semicolon if missing.
*
*/
$str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$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: Use rawurldecode() so it does not remove plus signs
*
*/
$str = rawurldecode($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.
*
*/
$str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_attribute_conversion'), $str);
$str = preg_replace_callback("/<([\w]+)[^>]*>/si", array($this, '_html_entity_decode_callback'), $str);
/*
Old Code that when modified to use preg_replace()'s above became more efficient memory-wise
if (preg_match_all("/[a-z]+=([\'\"]).*?\\1/si", $str, $matches))
{
for ($i = 0; $i < count($matches[0]); $i++)
{
if (stristr($matches[0][$i], '>'))
{
$str = str_replace( $matches['0'][$i],
str_replace('>', '&lt;', $matches[0][$i]),
$str);
}
}
}
if (preg_match_all("/<([\w]+)[^>]*>/si", $str, $matches))
{
for ($i = 0; $i < count($matches[0]); $i++)
{
$str = str_replace($matches[0][$i],
$this->_html_entity_decode($matches[0][$i], $charset),
$str);
}
}
*/
/*
* Convert all tabs to spaces
*
* This prevents strings like this: ja vascript
* NOTE: we deal with spaces between characters later.
* NOTE: preg_replace was found to be amazingly slow here on large blocks of data,
* so we use str_replace.
*
*/
$str = str_replace("\t", " ", $str);
/*
* Not Allowed Under Any Conditions
*/
$bad = array(
'document.cookie' => '[removed]',
'document.write' => '[removed]',
'.parentNode' => '[removed]',
'.innerHTML' => '[removed]',
'window.location' => '[removed]',
'-moz-binding' => '[removed]',
'<!--' => '&lt;!--',
'-->' => '--&gt;',
'<!CDATA[' => '&lt;![CDATA['
);
foreach ($bad as $key => $val)
{
$str = str_replace($key, $val, $str);
}
$bad = array(
"javascript\s*:" => '[removed]',
"expression\s*\(" => '[removed]', // CSS and IE
"Redirect\s+302" => '[removed]'
);
foreach ($bad as $key => $val)
{
$str = preg_replace("#".$key."#i", $val, $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('&lt;?php', '&lt;?PHP', '&lt;?', '?&gt;'), $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.
*
*/
$words = array('javascript', 'expression', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');
foreach ($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
*/
do
{
$original = $str;
if ((version_compare(PHP_VERSION, '5.0', '>=') === TRUE && stripos($str, '</a>') !== FALSE) OR
preg_match("/<\/a>/i", $str))
{
$str = preg_replace_callback("#<a.*?</a>#si", array($this, '_js_link_removal'), $str);
}
if ((version_compare(PHP_VERSION, '5.0', '>=') === TRUE && stripos($str, '<img') !== FALSE) OR
preg_match("/img/i", $str))
{
$str = preg_replace_callback("#<img.*?".">#si", array($this, '_js_img_removal'), $str);
}
if ((version_compare(PHP_VERSION, '5.0', '>=') === TRUE && (stripos($str, 'script') !== FALSE OR stripos($str, 'xss') !== FALSE)) OR
preg_match("/(script|xss)/i", $str))
{
$str = preg_replace("#</*(script|xss).*?\>#si", "", $str);
}
}
while($original != $str);
unset($original);
/*
* 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", "&lt;\\1\\2\\3&gt;", $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: &lt;blink&gt;
*
*/
$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', "&lt;\\1\\2\\3&gt;", $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 un-executable.
*
* For example: eval('some code')
* Becomes: eval&#40;'some code'&#41;
*
*/
$str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);
/*
* Final clean up
*
* This adds a bit of extra precaution in case
* something got through the above filters
*
*/
$bad = array(
'document.cookie' => '[removed]',
'document.write' => '[removed]',
'.parentNode' => '[removed]',
'.innerHTML' => '[removed]',
'window.location' => '[removed]',
'-moz-binding' => '[removed]',
'<!--' => '&lt;!--',
'-->' => '--&gt;',
'<!CDATA[' => '&lt;![CDATA['
);
foreach ($bad as $key => $val)
{
$str = str_replace($key, $val, $str);
}
$bad = array(
"javascript\s*:" => '[removed]',
"expression\s*\(" => '[removed]', // CSS and IE
"Redirect\s+302" => '[removed]'
);
foreach ($bad as $key => $val)
{
$str = preg_replace("#".$key."#i", $val, $str);
}
log_message('debug', "XSS Filtering completed");
return $str;
}
// --------------------------------------------------------------------
/**
* JS Link Removal
*
* Callback function for xss_clean() to sanitize links
* This limits the PCRE backtracks, making it more performance friendly
* and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
* PHP 5.2+ on link-heavy strings
*
* @access private
* @param array
* @return string
*/
function _js_link_removal($match)
{
return preg_replace("#<a.+?href=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>.*?</a>#si", "", $match[0]);
}
/**
* JS Image Removal
*
* Callback function for xss_clean() to sanitize image tags
* This limits the PCRE backtracks, making it more performance friendly
* and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
* PHP 5.2+ on image tag heavy strings
*
* @access private
* @param array
* @return string
*/
function _js_img_removal($match)
{
return preg_replace("#<img.+?src=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>#si", "", $match[0]);
}
// --------------------------------------------------------------------
/**
* Attribute Conversion
*
* Used as a callback for XSS Clean
*
* @access public
* @param array
* @return string
*/
function _attribute_conversion($match)
{
return str_replace('>', '&lt;', $match[0]);
}
// --------------------------------------------------------------------
/**
* HTML Entity Decode Callback
*
* Used as a callback for XSS Clean
*
* @access public
* @param array
* @return string
*/
function _html_entity_decode_callback($match)
{
global $CFG;
$charset = $CFG->item('charset');
return $this->_html_entity_decode($match[0], strtoupper($charset));
}
// --------------------------------------------------------------------
/**
* HTML Entities Decode
*
* This function is a replacement for html_entity_decode()
*
* In some versions of PHP the native function does not work
* when UTF-8 is the specified character set, so this gives us
* a work-around. More info here:
* http://bugs.php.net/bug.php?id=25670
*
* @access private
* @param string
* @param string
* @return string
*/
/* -------------------------------------------------
/* Replacement for html_entity_decode()
/* -------------------------------------------------*/
/*
NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
character set, and the PHP developers said they were not back porting the
fix to versions other than PHP 5.x.
*/
function _html_entity_decode($str, $charset='UTF-8')
{
if (stristr($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, ENT_COMPAT, $charset);
$str = preg_replace('~&#x([0-9a-f]{2,5})~ei', 'chr(hexdec("\\1"))', $str);
return preg_replace('~&#([0-9]{2,4})~e', 'chr(\\1)', $str);
}
// Numeric Entities
$str = preg_replace('~&#x([0-9a-f]{2,5});{0,1}~ei', 'chr(hexdec("\\1"))', $str);
$str = preg_replace('~&#([0-9]{2,4});{0,1}~e', 'chr(\\1)', $str);
// Literal Entities - Slightly slow so we do another check
if (stristr($str, '&') === FALSE)
{
$str = strtr($str, array_flip(get_html_translation_table(HTML_ENTITIES)));
}
return $str;
}
}
// END Input class