diff --git a/application/common.php b/application/common.php
index 7951c8b..dd4dd2f 100755
--- a/application/common.php
+++ b/application/common.php
@@ -408,3 +408,13 @@ if (!function_exists('check_cors_request')) {
}
}
}
+
+if (!function_exists('xss_clean')) {
+ /**
+ * 清理XSS
+ */
+ function xss_clean($content, $is_image = false)
+ {
+ return \app\common\library\Security::instance()->xss_clean($content, $is_image);
+ }
+}
diff --git a/application/common/library/Security.php b/application/common/library/Security.php
new file mode 100644
index 0000000..6832325
--- /dev/null
+++ b/application/common/library/Security.php
@@ -0,0 +1,874 @@
+<?php
+
+namespace app\common\library;
+
+use Exception;
+
+/**
+ * 安全过滤类
+ *
+ * @category Security
+ * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
+ * @license https://opensource.org/licenses/MIT MIT License
+ * @link https://codeigniter.com
+ * @author EllisLab Dev Team
+ */
+class Security
+{
+
+ protected static $instance = null;
+
+ /**
+ * List of sanitize filename strings
+ *
+ * @var array
+ */
+ public $filename_bad_chars = array(
+ '../',
+ '<!--',
+ '-->',
+ '<',
+ '>',
+ "'",
+ '"',
+ '&',
+ '$',
+ '#',
+ '{',
+ '}',
+ '[',
+ ']',
+ '=',
+ ';',
+ '?',
+ '%20',
+ '%22',
+ '%3c', // <
+ '%253c', // <
+ '%3e', // >
+ '%0e', // >
+ '%28', // (
+ '%29', // )
+ '%2528', // (
+ '%26', // &
+ '%24', // $
+ '%3f', // ?
+ '%3b', // ;
+ '%3d' // =
+ );
+
+ /**
+ * Character set
+ *
+ * Will be overridden by the constructor.
+ *
+ * @var string
+ */
+ public $charset = 'UTF-8';
+
+ /**
+ * XSS Hash
+ *
+ * Random Hash for protecting URLs.
+ *
+ * @var string
+ */
+ protected $_xss_hash;
+
+ /**
+ * List of never allowed strings
+ *
+ * @var array
+ */
+ protected $_never_allowed_str = array(
+ 'document.cookie' => '[removed]',
+ '(document).cookie' => '[removed]',
+ 'document.write' => '[removed]',
+ '(document).write' => '[removed]',
+ '.parentNode' => '[removed]',
+ '.innerHTML' => '[removed]',
+ '-moz-binding' => '[removed]',
+ '<!--' => '<!--',
+ '-->' => '-->',
+ '<![CDATA[' => '<![CDATA[',
+ '<comment>' => '<comment>',
+ '<%' => '<%'
+ );
+
+ /**
+ * List of never allowed regex replacements
+ *
+ * @var array
+ */
+ protected $_never_allowed_regex = array(
+ 'javascript\s*:',
+ '(\(?document\)?|\(?window\)?(\.document)?)\.(location|on\w*)',
+ 'expression\s*(\(|&\#40;)', // CSS and IE
+ 'vbscript\s*:', // IE, surprise!
+ 'wscript\s*:', // IE
+ 'jscript\s*:', // IE
+ 'vbs\s*:', // IE
+ 'Redirect\s+30\d',
+ "([\"'])?data\s*:[^\\1]*?base64[^\\1]*?,[^\\1]*?\\1?"
+ );
+
+ protected $options = [
+ 'placeholder' => '[removed]'
+ ];
+
+ /**
+ * Class constructor
+ *
+ * @return void
+ */
+ public function __construct($options = [])
+ {
+ $this->options = array_merge($this->options, $options);
+ foreach ($this->_never_allowed_str as $index => &$item) {
+ $item = str_replace('[removed]', $this->options['placeholder'], $item);
+ }
+ }
+
+ /**
+ *
+ * @param array $options 参数
+ * @return Security
+ */
+ public static function instance($options = [])
+ {
+ if (is_null(self::$instance)) {
+ self::$instance = new static($options);
+ }
+
+ return self::$instance;
+ }
+
+ /**
+ * XSS Clean
+ *
+ * Sanitizes data so that Cross Site Scripting Hacks can be
+ * prevented. This method 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: Should only be used to deal with data upon submission.
+ * It's not something that should be used for general
+ * runtime processing.
+ *
+ * @link http://channel.bitflux.ch/wiki/XSS_Prevention
+ * Based in part on some code and ideas from Bitflux.
+ *
+ * @link http://ha.ckers.org/xss.html
+ * 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.
+ *
+ * @param string|string[] $str Input data
+ * @param bool $is_image Whether the input is an image
+ * @return string
+ */
+ public function xss_clean($str, $is_image = false)
+ {
+ // Is the string an array?
+ if (is_array($str)) {
+ foreach ($str as $key => &$value) {
+ $str[$key] = $this->xss_clean($value);
+ }
+
+ return $str;
+ }
+
+ // Remove Invisible Characters
+ $str = $this->remove_invisible_characters($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
+ */
+ if (stripos($str, '%') !== false) {
+ do {
+ $oldstr = $str;
+ $str = rawurldecode($str);
+ $str = preg_replace_callback('#%(?:\s*[0-9a-f]){2,}#i', array($this, '_urldecodespaces'), $str);
+ } while ($oldstr !== $str);
+ unset($oldstr);
+ }
+
+ /*
+ * 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.
+ */
+ $str = preg_replace_callback("/[^a-z0-9>]+[a-z0-9]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);
+ $str = preg_replace_callback('/<\w+.*/si', array($this, '_decode_entity'), $str);
+
+ // Remove Invisible Characters Again!
+ $str = $this->remove_invisible_characters($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);
+
+ // Capture converted string for later comparison
+ $converted_string = $str;
+
+ // Remove Strings that are never allowed
+ $str = $this->_do_never_allowed($str);
+
+ /*
+ * Makes PHP tags safe
+ *
+ * Note: XML tags are inadvertently replaced too:
+ *
+ * <?xml
+ *
+ * But it doesn't seem to pose a problem.
+ */
+ if ($is_image === true) {
+ // Images have a tendency to have the PHP short opening and
+ // closing tags every so often so we skip those and only
+ // do the long opening tags.
+ $str = preg_replace('/<\?(php)/i', '<?\\1', $str);
+ } else {
+ $str = str_replace(array('<?', '?' . '>'), array('<?', '?>'), $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.
+ */
+ $words = array(
+ 'javascript',
+ 'expression',
+ 'vbscript',
+ 'jscript',
+ 'wscript',
+ 'vbs',
+ 'script',
+ 'base64',
+ 'applet',
+ 'alert',
+ 'document',
+ 'write',
+ 'cookie',
+ 'window',
+ 'confirm',
+ 'prompt',
+ 'eval'
+ );
+
+ foreach ($words as $word) {
+ $word = implode('\s*', str_split($word)) . '\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"
+ $str = preg_replace_callback('#(' . substr($word, 0, -3) . ')(\W)#is', array($this, '_compact_exploded_words'), $str);
+ }
+
+ /*
+ * Remove disallowed Javascript in links or img tags
+ * We used to do some version comparisons and use of stripos(),
+ * but it is dog slow compared to these simplified non-capturing
+ * preg_match(), especially if the pattern exists in the string
+ *
+ * Note: It was reported that not only space characters, but all in
+ * the following pattern can be parsed as separators between a tag name
+ * and its attributes: [\d\s"\'`;,\/\=\(\x00\x0B\x09\x0C]
+ * ... however, $this->remove_invisible_characters() above already strips the
+ * hex-encoded ones, so we'll skip them below.
+ */
+ do {
+ $original = $str;
+
+ if (preg_match('/<a/i', $str)) {
+ $str = preg_replace_callback('#<a(?:rea)?[^a-z0-9>]+([^>]*?)(?:>|$)#si', array($this, '_js_link_removal'), $str);
+ }
+
+ if (preg_match('/<img/i', $str)) {
+ $str = preg_replace_callback('#<img[^a-z0-9]+([^>]*?)(?:\s?/?>|$)#si', array($this, '_js_img_removal'), $str);
+ }
+
+ if (preg_match('/script|xss/i', $str)) {
+ $str = preg_replace('#</*(?:script|xss).*?>#si', $this->options['placeholder'], $str);
+ }
+ } while ($original !== $str);
+ unset($original);
+
+ /*
+ * 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>
+ */
+ $pattern = '#'
+ . '<((?<slash>/*\s*)((?<tagName>[a-z0-9]+)(?=[^a-z0-9]|$)|.+)' // tag start and name, followed by a non-tag character
+ . '[^\s\042\047a-z0-9>/=]*' // a valid attribute character immediately after the tag would count as a separator
+ // optional attributes
+ . '(?<attributes>(?:[\s\042\047/=]*' // non-attribute characters, excluding > (tag close) for obvious reasons
+ . '[^\s\042\047>/=]+' // attribute characters
+ // optional attribute-value
+ . '(?:\s*=' // attribute-value separator
+ . '(?:[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*))' // single, double or non-quoted value
+ . ')?' // end optional attribute-value group
+ . ')*)' // end optional attributes group
+ . '[^>]*)(?<closeTag>\>)?#isS';
+
+ // Note: It would be nice to optimize this for speed, BUT
+ // only matching the naughty elements here results in
+ // false positives and in turn - vulnerabilities!
+ do {
+ $old_str = $str;
+ $str = preg_replace_callback($pattern, array($this, '_sanitize_naughty_html'), $str);
+ } while ($old_str !== $str);
+ unset($old_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('some code')
+ */
+ $str = preg_replace(
+ '#(alert|prompt|confirm|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si',
+ '\\1\\2(\\3)',
+ $str
+ );
+
+ // Same thing, but for "tag functions" (e.g. eval`some code`)
+ $str = preg_replace(
+ '#(alert|prompt|confirm|cmd|passthru|eval|exec|expression|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
+ $str = $this->_do_never_allowed($str);
+
+ /*
+ * Images are Handled in a Special Way
+ * - Essentially, we want to know that after all of the character
+ * conversion is done whether any unwanted, likely XSS, code was found.
+ * If not, we return TRUE, as the image is clean.
+ * However, if the string post-conversion does not matched the
+ * string post-removal of XSS, then it fails, as there was unwanted XSS
+ * code found and removed/changed during processing.
+ */
+ if ($is_image === true) {
+ return ($str === $converted_string);
+ }
+
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * XSS Hash
+ *
+ * Generates the XSS hash if needed and returns it.
+ *
+ * @return string XSS hash
+ */
+ public function xss_hash()
+ {
+ if ($this->_xss_hash === null) {
+ $rand = $this->get_random_bytes(16);
+ $this->_xss_hash = ($rand === false)
+ ? md5(uniqid(mt_rand(), true))
+ : bin2hex($rand);
+ }
+
+ return $this->_xss_hash;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Get random bytes
+ *
+ * @param int $length Output length
+ * @return string
+ */
+ public function get_random_bytes($length)
+ {
+ if (empty($length) OR !ctype_digit((string)$length)) {
+ return false;
+ }
+
+ if (function_exists('random_bytes')) {
+ try {
+ // The cast is required to avoid TypeError
+ return random_bytes((int)$length);
+ } catch (Exception $e) {
+ // If random_bytes() can't do the job, we can't either ...
+ // There's no point in using fallbacks.
+ return false;
+ }
+ }
+
+ // Unfortunately, none of the following PRNGs is guaranteed to exist ...
+ if (defined('MCRYPT_DEV_URANDOM') && ($output = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM)) !== false) {
+ return $output;
+ }
+
+
+ if (is_readable('/dev/urandom') && ($fp = fopen('/dev/urandom', 'rb')) !== false) {
+ // Try not to waste entropy ...
+ stream_set_chunk_size($fp, $length);
+ $output = fread($fp, $length);
+ fclose($fp);
+ if ($output !== false) {
+ return $output;
+ }
+ }
+
+ if (function_exists('openssl_random_pseudo_bytes')) {
+ return openssl_random_pseudo_bytes($length);
+ }
+
+ return false;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entities Decode
+ *
+ * A replacement for html_entity_decode()
+ *
+ * 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.
+ *
+ * @link https://secure.php.net/html-entity-decode
+ *
+ * @param string $str Input
+ * @param string $charset Character set
+ * @return string
+ */
+ public function entity_decode($str, $charset = null)
+ {
+ if (strpos($str, '&') === false) {
+ return $str;
+ }
+
+ static $_entities;
+
+ isset($charset) OR $charset = $this->charset;
+ isset($_entities) OR $_entities = array_map('strtolower', get_html_translation_table(HTML_ENTITIES, ENT_COMPAT | ENT_HTML5, $charset));
+
+ do {
+ $str_compare = $str;
+
+ // Decode standard entities, avoiding false positives
+ if (preg_match_all('/&[a-z]{2,}(?![a-z;])/i', $str, $matches)) {
+ $replace = array();
+ $matches = array_unique(array_map('strtolower', $matches[0]));
+ foreach ($matches as &$match) {
+ if (($char = array_search($match . ';', $_entities, true)) !== false) {
+ $replace[$match] = $char;
+ }
+ }
+
+ $str = str_replace(array_keys($replace), array_values($replace), $str);
+ }
+
+ // Decode numeric & UTF16 two byte entities
+ $str = html_entity_decode(
+ preg_replace('/(&#(?:x0*[0-9a-f]{2,5}(?![0-9a-f;])|(?:0*\d{2,4}(?![0-9;]))))/iS', '$1;', $str),
+ ENT_COMPAT | ENT_HTML5,
+ $charset
+ );
+ } while ($str_compare !== $str);
+ return $str;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Sanitize Filename
+ *
+ * @param string $str Input file name
+ * @param bool $relative_path Whether to preserve paths
+ * @return string
+ */
+ public function sanitize_filename($str, $relative_path = false)
+ {
+ $bad = $this->filename_bad_chars;
+
+ if (!$relative_path) {
+ $bad[] = './';
+ $bad[] = '/';
+ }
+
+ $str = $this->remove_invisible_characters($str, false);
+
+ do {
+ $old = $str;
+ $str = str_replace($bad, '', $str);
+ } while ($old !== $str);
+
+ return stripslashes($str);
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * Strip Image Tags
+ *
+ * @param string $str
+ * @return string
+ */
+ public function strip_image_tags($str)
+ {
+ return preg_replace(
+ array(
+ '#<img[\s/]+.*?src\s*=\s*(["\'])([^\\1]+?)\\1.*?\>#i',
+ '#<img[\s/]+.*?src\s*=\s*?(([^\s"\'=<>`]+)).*?\>#i'
+ ),
+ '\\2',
+ $str
+ );
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * URL-decode taking spaces into account
+ *
+ * @param array $matches
+ * @return string
+ */
+ protected function _urldecodespaces($matches)
+ {
+ $input = $matches[0];
+ $nospaces = preg_replace('#\s+#', '', $input);
+ return ($nospaces === $input)
+ ? $input
+ : rawurldecode($nospaces);
+ }
+
+ // ----------------------------------------------------------------
+
+ /**
+ * Compact Exploded Words
+ *
+ * Callback method for xss_clean() to remove whitespace from
+ * things like 'j a v a s c r i p t'.
+ *
+ * @param array $matches
+ * @return string
+ */
+ protected function _compact_exploded_words($matches)
+ {
+ return preg_replace('/\s+/s', '', $matches[1]) . $matches[2];
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Sanitize Naughty HTML
+ *
+ * Callback method for xss_clean() to remove naughty HTML elements.
+ *
+ * @param array $matches
+ * @return string
+ */
+ protected function _sanitize_naughty_html($matches)
+ {
+ static $naughty_tags = array(
+ 'alert',
+ 'area',
+ 'prompt',
+ 'confirm',
+ 'applet',
+ 'audio',
+ 'basefont',
+ 'base',
+ 'behavior',
+ 'bgsound',
+ 'blink',
+ 'body',
+ 'embed',
+ 'expression',
+ 'form',
+ 'frameset',
+ 'frame',
+ 'head',
+ 'html',
+ 'ilayer',
+ 'iframe',
+ 'input',
+ 'button',
+ 'select',
+ 'isindex',
+ 'layer',
+ 'link',
+ 'meta',
+ 'keygen',
+ 'object',
+ 'plaintext',
+ 'style',
+ 'script',
+ 'textarea',
+ 'title',
+ 'math',
+ 'video',
+ 'svg',
+ 'xml',
+ 'xss'
+ );
+
+ static $evil_attributes = array(
+ 'on\w+',
+ 'style',
+ 'xmlns',
+ 'formaction',
+ 'form',
+ 'xlink:href',
+ 'FSCommand',
+ 'seekSegmentTime'
+ );
+
+ // First, escape unclosed tags
+ if (empty($matches['closeTag'])) {
+ return '<' . $matches[1];
+ } // Is the element that we caught naughty? If so, escape it
+ elseif (in_array(strtolower($matches['tagName']), $naughty_tags, true)) {
+ return '<' . $matches[1] . '>';
+ } // For other tags, see if their attributes are "evil" and strip those
+ elseif (isset($matches['attributes'])) {
+ // We'll store the already filtered attributes here
+ $attributes = array();
+
+ // Attribute-catching pattern
+ $attributes_pattern = '#'
+ . '(?<name>[^\s\042\047>/=]+)' // attribute characters
+ // optional attribute-value
+ . '(?:\s*=(?<value>[^\s\042\047=><`]+|\s*\042[^\042]*\042|\s*\047[^\047]*\047|\s*(?U:[^\s\042\047=><`]*)))' // attribute-value separator
+ . '#i';
+
+ // Blacklist pattern for evil attribute names
+ $is_evil_pattern = '#^(' . implode('|', $evil_attributes) . ')$#i';
+
+ // Each iteration filters a single attribute
+ do {
+ // Strip any non-alpha characters that may precede an attribute.
+ // Browsers often parse these incorrectly and that has been a
+ // of numerous XSS issues we've had.
+ $matches['attributes'] = preg_replace('#^[^a-z]+#i', '', $matches['attributes']);
+
+ if (!preg_match($attributes_pattern, $matches['attributes'], $attribute, PREG_OFFSET_CAPTURE)) {
+ // No (valid) attribute found? Discard everything else inside the tag
+ break;
+ }
+
+ if (
+ // Is it indeed an "evil" attribute?
+ preg_match($is_evil_pattern, $attribute['name'][0])
+ // Or does it have an equals sign, but no value and not quoted? Strip that too!
+ OR (trim($attribute['value'][0]) === '')
+ ) {
+ $attributes[] = 'xss=removed';
+ } else {
+ $attributes[] = $attribute[0][0];
+ }
+
+ $matches['attributes'] = substr($matches['attributes'], $attribute[0][1] + strlen($attribute[0][0]));
+ } while ($matches['attributes'] !== '');
+
+ $attributes = empty($attributes)
+ ? ''
+ : ' ' . implode(' ', $attributes);
+ return '<' . $matches['slash'] . $matches['tagName'] . $attributes . '>';
+ }
+
+ return $matches[0];
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * JS Link Removal
+ *
+ * Callback method 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.
+ *
+ * @param array $match
+ * @return string
+ */
+ protected function _js_link_removal($match)
+ {
+ return str_replace(
+ $match[1],
+ preg_replace(
+ '#href=.*?(?:(?:alert|prompt|confirm)(?:\(|&\#40;|`|&\#96;)|javascript:|livescript:|mocha:|charset=|window\.|\(?document\)?\.|\.cookie|<script|<xss|d\s*a\s*t\s*a\s*:)#si',
+ '',
+ $this->_filter_attributes($match[1])
+ ),
+ $match[0]
+ );
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * JS Image Removal
+ *
+ * Callback method 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.
+ *
+ * @param array $match
+ * @return string
+ */
+ protected function _js_img_removal($match)
+ {
+ return str_replace(
+ $match[1],
+ preg_replace(
+ '#src=.*?(?:(?:alert|prompt|confirm|eval)(?:\(|&\#40;|`|&\#96;)|javascript:|livescript:|mocha:|charset=|window\.|\(?document\)?\.|\.cookie|<script|<xss|base64\s*,)#si',
+ '',
+ $this->_filter_attributes($match[1])
+ ),
+ $match[0]
+ );
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Attribute Conversion
+ *
+ * @param array $match
+ * @return string
+ */
+ protected function _convert_attribute($match)
+ {
+ return str_replace(array('>', '<', '\\'), array('>', '<', '\\\\'), $match[0]);
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Filter Attributes
+ *
+ * Filters tag attributes for consistency and safety.
+ *
+ * @param string $str
+ * @return string
+ */
+ protected function _filter_attributes($str)
+ {
+ $out = '';
+ if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches)) {
+ foreach ($matches[0] as $match) {
+ $out .= preg_replace('#/\*.*?\*/#s', '', $match);
+ }
+ }
+
+ return $out;
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * HTML Entity Decode Callback
+ *
+ * @param array $match
+ * @return string
+ */
+ protected function _decode_entity($match)
+ {
+ // Protect GET variables in URLs
+ // 901119URL5918AMP18930PROTECT8198
+ $match = preg_replace('|\&([a-z\_0-9\-]+)\=([a-z\_0-9\-/]+)|i', $this->xss_hash() . '\\1=\\2', $match[0]);
+
+ // Decode, then un-protect URL GET vars
+ return str_replace(
+ $this->xss_hash(),
+ '&',
+ $this->entity_decode($match, $this->charset)
+ );
+ }
+
+ // --------------------------------------------------------------------
+
+ /**
+ * Do Never Allowed
+ *
+ * @param string
+ * @return string
+ */
+ protected function _do_never_allowed($str)
+ {
+ $str = str_replace(array_keys($this->_never_allowed_str), $this->_never_allowed_str, $str);
+
+ foreach ($this->_never_allowed_regex as $regex) {
+ $str = preg_replace('#' . $regex . '#is', $this->options['placeholder'], $str);
+ }
+
+ return $str;
+ }
+
+ /**
+ * Remove Invisible Characters
+ */
+ public function remove_invisible_characters($str, $url_encoded = true)
+ {
+ $non_displayables = array();
+
+ // every control character except newline (dec 10),
+ // carriage return (dec 13) and horizontal tab (dec 09)
+ if ($url_encoded) {
+ $non_displayables[] = '/%0[0-8bcef]/i'; // url encoded 00-08, 11, 12, 14, 15
+ $non_displayables[] = '/%1[0-9a-f]/i'; // url encoded 16-31
+ $non_displayables[] = '/%7f/i'; // url encoded 127
+ }
+
+ $non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S'; // 00-08, 11, 12, 14-31, 127
+
+ do {
+ $str = preg_replace($non_displayables, '', $str, -1, $count);
+ } while ($count);
+
+ return $str;
+ }
+
+}