Replaced PHP strip_tags with D7 filter_xss. Good thing we cache this..
Frank Ronny Larsen
parent
7af599ae0d
commit
706c61bfe8
326
h5p.classes.php
326
h5p.classes.php
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@ -1208,11 +1208,8 @@ class H5PContentValidator {
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if (in_array('ul', $tags) || in_array('ol', $tags) && ! in_array('li', $tags)) {
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if (in_array('ul', $tags) || in_array('ol', $tags) && ! in_array('li', $tags)) {
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$tags[] = 'li';
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$tags[] = 'li';
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}
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}
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// Convert array of tagNames to string of bracketed tags
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$allowedtags = implode('', array_map(array($this, 'bracketTags'), $tags));
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// Strip invalid HTML tags.
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// Strip invalid HTML tags.
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$text = strip_tags($text, $allowedtags);
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$text = $this->filter_xss($text, $tags);
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}
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}
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else {
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else {
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// Filter text to plain text.
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// Filter text to plain text.
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@ -1440,5 +1437,326 @@ class H5PContentValidator {
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$this->h5pF->setErrorMessage($this->h5pF->t('Library used in content is not a valid library according to semantics'));
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$this->h5pF->setErrorMessage($this->h5pF->t('Library used in content is not a valid library according to semantics'));
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}
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}
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}
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}
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// XSS filters copied from drupal 7 common.inc. Some modifications done to
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// replace Drupal one-liner functions with corresponding flat PHP.
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/**
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* Filters HTML to prevent cross-site-scripting (XSS) vulnerabilities.
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*
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* Based on kses by Ulf Harnhammar, see http://sourceforge.net/projects/kses.
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* For examples of various XSS attacks, see: http://ha.ckers.org/xss.html.
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*
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* This code does four things:
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* - Removes characters and constructs that can trick browsers.
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* - Makes sure all HTML entities are well-formed.
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* - Makes sure all HTML tags and attributes are well-formed.
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* - Makes sure no HTML tags contain URLs with a disallowed protocol (e.g.
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* javascript:).
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*
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* @param $string
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* The string with raw HTML in it. It will be stripped of everything that can
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* cause an XSS attack.
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* @param $allowed_tags
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* An array of allowed tags.
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*
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* @return
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* An XSS safe version of $string, or an empty string if $string is not
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* valid UTF-8.
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*
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* @ingroup sanitization
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*/
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private function filter_xss($string, $allowed_tags = array('a', 'em', 'strong', 'cite', 'blockquote', 'code', 'ul', 'ol', 'li', 'dl', 'dt', 'dd')) {
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if (strlen($string) == 0) {
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return $string;
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}
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// Only operate on valid UTF-8 strings. This is necessary to prevent cross
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// site scripting issues on Internet Explorer 6. (Line copied from
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// drupal_validate_utf8)
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if (preg_match('/^./us', $string) != 1) {
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return '';
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}
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// Store the text format.
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$this->_filter_xss_split($allowed_tags, TRUE);
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// Remove NULL characters (ignored by some browsers).
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$string = str_replace(chr(0), '', $string);
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// Remove Netscape 4 JS entities.
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$string = preg_replace('%&\s*\{[^}]*(\}\s*;?|$)%', '', $string);
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// Defuse all HTML entities.
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$string = str_replace('&', '&', $string);
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// Change back only well-formed entities in our whitelist:
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// Decimal numeric entities.
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$string = preg_replace('/&#([0-9]+;)/', '&#\1', $string);
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// Hexadecimal numeric entities.
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$string = preg_replace('/&#[Xx]0*((?:[0-9A-Fa-f]{2})+;)/', '&#x\1', $string);
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// Named entities.
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$string = preg_replace('/&([A-Za-z][A-Za-z0-9]*;)/', '&\1', $string);
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return preg_replace_callback('%
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(
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<(?=[^a-zA-Z!/]) # a lone <
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| # or
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<!--.*?--> # a comment
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| # or
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<[^>]*(>|$) # a string that starts with a <, up until the > or the end of the string
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| # or
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> # just a >
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)%x', array($this, '_filter_xss_split'), $string);
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}
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/**
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* Processes an HTML tag.
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*
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* @param $m
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* An array with various meaning depending on the value of $store.
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* If $store is TRUE then the array contains the allowed tags.
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* If $store is FALSE then the array has one element, the HTML tag to process.
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* @param $store
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* Whether to store $m.
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*
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* @return
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* If the element isn't allowed, an empty string. Otherwise, the cleaned up
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* version of the HTML element.
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*/
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private function _filter_xss_split($m, $store = FALSE) {
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static $allowed_html;
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if ($store) {
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$allowed_html = array_flip($m);
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return;
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}
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$string = $m[1];
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if (substr($string, 0, 1) != '<') {
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// We matched a lone ">" character.
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return '>';
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}
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elseif (strlen($string) == 1) {
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// We matched a lone "<" character.
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return '<';
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}
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if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9]+)([^>]*)>?|(<!--.*?-->)$%', $string, $matches)) {
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// Seriously malformed.
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return '';
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}
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$slash = trim($matches[1]);
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$elem = &$matches[2];
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$attrlist = &$matches[3];
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$comment = &$matches[4];
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if ($comment) {
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$elem = '!--';
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}
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if (!isset($allowed_html[strtolower($elem)])) {
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// Disallowed HTML element.
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return '';
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}
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if ($comment) {
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return $comment;
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}
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if ($slash != '') {
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return "</$elem>";
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}
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// Is there a closing XHTML slash at the end of the attributes?
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$attrlist = preg_replace('%(\s?)/\s*$%', '\1', $attrlist, -1, $count);
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$xhtml_slash = $count ? ' /' : '';
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// Clean up attributes.
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$attr2 = implode(' ', $this->_filter_xss_attributes($attrlist));
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$attr2 = preg_replace('/[<>]/', '', $attr2);
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$attr2 = strlen($attr2) ? ' ' . $attr2 : '';
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return "<$elem$attr2$xhtml_slash>";
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}
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/**
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* Processes a string of HTML attributes.
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*
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* @return
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* Cleaned up version of the HTML attributes.
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*/
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private function _filter_xss_attributes($attr) {
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$attrarr = array();
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$mode = 0;
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$attrname = '';
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while (strlen($attr) != 0) {
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// Was the last operation successful?
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$working = 0;
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switch ($mode) {
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case 0:
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// Attribute name, href for instance.
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if (preg_match('/^([-a-zA-Z]+)/', $attr, $match)) {
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$attrname = strtolower($match[1]);
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$skip = ($attrname == 'style' || substr($attrname, 0, 2) == 'on');
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$working = $mode = 1;
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$attr = preg_replace('/^[-a-zA-Z]+/', '', $attr);
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}
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break;
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case 1:
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// Equals sign or valueless ("selected").
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if (preg_match('/^\s*=\s*/', $attr)) {
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$working = 1; $mode = 2;
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$attr = preg_replace('/^\s*=\s*/', '', $attr);
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break;
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}
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if (preg_match('/^\s+/', $attr)) {
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$working = 1; $mode = 0;
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if (!$skip) {
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$attrarr[] = $attrname;
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}
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$attr = preg_replace('/^\s+/', '', $attr);
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}
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break;
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case 2:
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// Attribute value, a URL after href= for instance.
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if (preg_match('/^"([^"]*)"(\s+|$)/', $attr, $match)) {
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$thisval = $this->filter_xss_bad_protocol($match[1]);
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if (!$skip) {
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$attrarr[] = "$attrname=\"$thisval\"";
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}
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$working = 1;
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$mode = 0;
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$attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr);
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break;
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}
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if (preg_match("/^'([^']*)'(\s+|$)/", $attr, $match)) {
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$thisval = $this->filter_xss_bad_protocol($match[1]);
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if (!$skip) {
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$attrarr[] = "$attrname='$thisval'";
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}
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$working = 1; $mode = 0;
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$attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr);
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break;
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}
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if (preg_match("%^([^\s\"']+)(\s+|$)%", $attr, $match)) {
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$thisval = $this->filter_xss_bad_protocol($match[1]);
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if (!$skip) {
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$attrarr[] = "$attrname=\"$thisval\"";
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}
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$working = 1; $mode = 0;
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$attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
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}
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break;
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}
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if ($working == 0) {
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// Not well formed; remove and try again.
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$attr = preg_replace('/
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^
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(
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"[^"]*("|$) # - a string that starts with a double quote, up until the next double quote or the end of the string
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| # or
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\'[^\']*(\'|$)| # - a string that starts with a quote, up until the next quote or the end of the string
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| # or
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\S # - a non-whitespace character
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)* # any number of the above three
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\s* # any number of whitespaces
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/x', '', $attr);
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$mode = 0;
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}
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}
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// The attribute list ends with a valueless attribute like "selected".
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if ($mode == 1 && !$skip) {
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$attrarr[] = $attrname;
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}
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return $attrarr;
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}
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/**
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* Processes an HTML attribute value and strips dangerous protocols from URLs.
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*
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* @param $string
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* The string with the attribute value.
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* @param $decode
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* (deprecated) Whether to decode entities in the $string. Set to FALSE if the
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* $string is in plain text, TRUE otherwise. Defaults to TRUE. This parameter
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* is deprecated and will be removed in Drupal 8. To process a plain-text URI,
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* call _strip_dangerous_protocols() or check_url() instead.
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*
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* @return
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* Cleaned up and HTML-escaped version of $string.
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*/
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private function filter_xss_bad_protocol($string, $decode = TRUE) {
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// Get the plain text representation of the attribute value (i.e. its meaning).
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// @todo Remove the $decode parameter in Drupal 8, and always assume an HTML
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// string that needs decoding.
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if ($decode) {
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$string = html_entity_decode($string, ENT_QUOTES, 'UTF-8');
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}
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return check_plain($this->_strip_dangerous_protocols($string));
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}
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/**
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* Strips dangerous protocols (e.g. 'javascript:') from a URI.
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*
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* This function must be called for all URIs within user-entered input prior
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* to being output to an HTML attribute value. It is often called as part of
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* check_url() or filter_xss(), but those functions return an HTML-encoded
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* string, so this function can be called independently when the output needs to
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* be a plain-text string for passing to t(), l(), drupal_attributes(), or
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* another function that will call check_plain() separately.
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*
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* @param $uri
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* A plain-text URI that might contain dangerous protocols.
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*
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* @return
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* A plain-text URI stripped of dangerous protocols. As with all plain-text
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* strings, this return value must not be output to an HTML page without
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* check_plain() being called on it. However, it can be passed to functions
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* expecting plain-text strings.
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*
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* @see check_url()
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*/
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private function _strip_dangerous_protocols($uri) {
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static $allowed_protocols;
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if (!isset($allowed_protocols)) {
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$allowed_protocols = array_flip(array('ftp', 'http', 'https', 'mailto'));
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}
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// Iteratively remove any invalid protocol found.
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do {
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$before = $uri;
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$colonpos = strpos($uri, ':');
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if ($colonpos > 0) {
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// We found a colon, possibly a protocol. Verify.
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$protocol = substr($uri, 0, $colonpos);
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// If a colon is preceded by a slash, question mark or hash, it cannot
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// possibly be part of the URL scheme. This must be a relative URL, which
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// inherits the (safe) protocol of the base document.
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if (preg_match('![/?#]!', $protocol)) {
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break;
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}
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// Check if this is a disallowed protocol. Per RFC2616, section 3.2.3
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// (URI Comparison) scheme comparison must be case-insensitive.
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if (!isset($allowed_protocols[strtolower($protocol)])) {
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$uri = substr($uri, $colonpos + 1);
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}
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}
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} while ($before != $uri);
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return $uri;
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}
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}
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}
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?>
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?>
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