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Diffstat (limited to 'system/libraries/Input.php')
| -rw-r--r-- | system/libraries/Input.php | 585 |
1 files changed, 585 insertions, 0 deletions
diff --git a/system/libraries/Input.php b/system/libraries/Input.php new file mode 100644 index 000000000..6aba5dd43 --- /dev/null +++ b/system/libraries/Input.php @@ -0,0 +1,585 @@ +<?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); // <?php BBEdit bug fix + + /* + * 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 +?>
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