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