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authoradmin <devnull@localhost>2006-08-25 19:25:49 +0200
committeradmin <devnull@localhost>2006-08-25 19:25:49 +0200
commitb0dd10f8171945e0c1f3527dd1e9d18b043e01a7 (patch)
treec3583ba09e72217683c4304f4690df6ce39ba731 /system/libraries/Input.php
Initial Import
Diffstat (limited to 'system/libraries/Input.php')
-rw-r--r--system/libraries/Input.php585
1 files changed, 585 insertions, 0 deletions
diff --git a/system/libraries/Input.php b/system/libraries/Input.php
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+<?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('&lt;?php', '&lt;?PHP', '&lt;?', '?&gt;'), $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: &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 unexecutable.
+ *
+ * For example: eval('some code')
+ * Becomes: eval&#40;'some code'&#41;
+ *
+ */
+ $str = preg_replace('#(alert|cmd|passthru|eval|exec|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
+ *
+ */
+ $bad = array(
+ 'document.cookie' => '',
+ 'document.write' => '',
+ 'window.location' => '',
+ "javascript\s*:" => '',
+ "Redirect\s+302" => '',
+ '<!--' => '&lt;!--',
+ '-->' => '--&gt;'
+ );
+
+ foreach ($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
+?> \ No newline at end of file