<?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 $this->user_agent; } // END user_agent() // -------------------------------------------------------------------- /** * XSS Clean * * Sanitizes data so that Cross Site Scripting Hacks can be * prevented.� This function does a fair amount of work but * it is extremely thorough, designed to prevent even the * most obscure XSS attempts.� Nothing is ever 100% foolproof, * of course, but I haven't been able to get anything passed * the filter. * * Note: This function should only be used to deal with data * upon submission.� It's not something that should * be used for general runtime processing. * * This function was based in part on some code and ideas I * got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention * * To help develop this script I used this great list of * vulnerabilities along with a few other hacks I've * harvested from examining vulnerabilities in other programs: * http://ha.ckers.org/xss.html * * @access public * @param string * @return string */ function xss_clean($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 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, 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 ?>