private
*
* @global array $pass_allowed_html
* @global array $pass_allowed_protocols
*
* @return string
*/
function _wp_kses_split_callback( $match ) {
global $pass_allowed_html, $pass_allowed_protocols;
return wp_kses_split2( $match[0], $pass_allowed_html, $pass_allowed_protocols );
}
/**
* Callback for wp_kses_split for fixing malformed HTML tags.
*
* This function does a lot of work. It rejects some very malformed things like
* <:::>. It returns an empty string, if the element isn't allowed (look ma, no
* strip_tags()!). Otherwise it splits the tag into an element and an attribute
* list.
*
* After the tag is split into an element and an attribute list, it is run
* through another filter which will remove illegal attributes and once that is
* completed, will be returned.
*
* @access private
* @since 1.0.0
*
* @param string $string Content to filter
* @param array $allowed_html Allowed HTML elements
* @param array $allowed_protocols Allowed protocols to keep
* @return string Fixed HTML element
*/
function wp_kses_split2($string, $allowed_html, $allowed_protocols) {
$string = wp_kses_stripslashes($string);
if (substr($string, 0, 1) != '<')
return '>';
// It matched a ">" character
if ( ''), '', $string );
while ( $string != ($newstring = wp_kses($string, $allowed_html, $allowed_protocols)) )
$string = $newstring;
if ( $string == '' )
return '';
// prevent multiple dashes in comments
$string = preg_replace('/--+/', '-', $string);
// prevent three dashes closing a comment
$string = preg_replace('/-$/', '', $string);
return "";
}
// Allow HTML comments
if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9-]+)([^>]*)>?$%', $string, $matches))
return '';
// It's seriously malformed
$slash = trim($matches[1]);
$elem = $matches[2];
$attrlist = $matches[3];
if ( ! is_array( $allowed_html ) )
$allowed_html = wp_kses_allowed_html( $allowed_html );
if ( ! isset($allowed_html[strtolower($elem)]) )
return '';
// They are using a not allowed HTML element
if ($slash != '')
return "$elem>";
// No attributes are allowed for closing elements
return wp_kses_attr( $elem, $attrlist, $allowed_html, $allowed_protocols );
}
/**
* Removes all attributes, if none are allowed for this element.
*
* If some are allowed it calls wp_kses_hair() to split them further, and then
* it builds up new HTML code from the data that kses_hair() returns. It also
* removes "<" and ">" characters, if there are any left. One more thing it does
* is to check if the tag has a closing XHTML slash, and if it does, it puts one
* in the returned code as well.
*
* @since 1.0.0
*
* @param string $element HTML element/tag
* @param string $attr HTML attributes from HTML element to closing HTML element tag
* @param array $allowed_html Allowed HTML elements
* @param array $allowed_protocols Allowed protocols to keep
* @return string Sanitized HTML element
*/
function wp_kses_attr($element, $attr, $allowed_html, $allowed_protocols) {
if ( ! is_array( $allowed_html ) )
$allowed_html = wp_kses_allowed_html( $allowed_html );
// Is there a closing XHTML slash at the end of the attributes?
$xhtml_slash = '';
if (preg_match('%\s*/\s*$%', $attr))
$xhtml_slash = ' /';
// Are any attributes allowed at all for this element?
$element_low = strtolower( $element );
if ( empty( $allowed_html[ $element_low ] ) || true === $allowed_html[ $element_low ] ) {
return "<$element$xhtml_slash>";
}
// Split it
$attrarr = wp_kses_hair($attr, $allowed_protocols);
// Go through $attrarr, and save the allowed attributes for this element
// in $attr2
$attr2 = '';
foreach ( $attrarr as $arreach ) {
if ( wp_kses_attr_check( $arreach['name'], $arreach['value'], $arreach['whole'], $arreach['vless'], $element, $allowed_html ) ) {
$attr2 .= ' '.$arreach['whole'];
}
}
// Remove any "<" or ">" characters
$attr2 = preg_replace('/[<>]/', '', $attr2);
return "<$element$attr2$xhtml_slash>";
}
/**
* Determine whether an attribute is allowed.
*
* @since 4.2.3
*
* @param string $name The attribute name. Returns empty string when not allowed.
* @param string $value The attribute value. Returns a filtered value.
* @param string $whole The name=value input. Returns filtered input.
* @param string $vless 'y' when attribute like "enabled", otherwise 'n'.
* @param string $element The name of the element to which this attribute belongs.
* @param array $allowed_html The full list of allowed elements and attributes.
* @return bool Is the attribute allowed?
*/
function wp_kses_attr_check( &$name, &$value, &$whole, $vless, $element, $allowed_html ) {
$allowed_attr = $allowed_html[strtolower( $element )];
$name_low = strtolower( $name );
if ( ! isset( $allowed_attr[$name_low] ) || '' == $allowed_attr[$name_low] ) {
$name = $value = $whole = '';
return false;
}
if ( 'style' == $name_low ) {
$new_value = safecss_filter_attr( $value );
if ( empty( $new_value ) ) {
$name = $value = $whole = '';
return false;
}
$whole = str_replace( $value, $new_value, $whole );
$value = $new_value;
}
if ( is_array( $allowed_attr[$name_low] ) ) {
// there are some checks
foreach ( $allowed_attr[$name_low] as $currkey => $currval ) {
if ( ! wp_kses_check_attr_val( $value, $vless, $currkey, $currval ) ) {
$name = $value = $whole = '';
return false;
}
}
}
return true;
}
/**
* Builds an attribute list from string containing attributes.
*
* This function does a lot of work. It parses an attribute list into an array
* with attribute data, and tries to do the right thing even if it gets weird
* input. It will add quotes around attribute values that don't have any quotes
* or apostrophes around them, to make it easier to produce HTML code that will
* conform to W3C's HTML specification. It will also remove bad URL protocols
* from attribute values. It also reduces duplicate attributes by using the
* attribute defined first (foo='bar' foo='baz' will result in foo='bar').
*
* @since 1.0.0
*
* @param string $attr Attribute list from HTML element to closing HTML element tag
* @param array $allowed_protocols Allowed protocols to keep
* @return array List of attributes after parsing
*/
function wp_kses_hair($attr, $allowed_protocols) {
$attrarr = array();
$mode = 0;
$attrname = '';
$uris = wp_kses_uri_attributes();
// Loop through the whole attribute list
while (strlen($attr) != 0) {
$working = 0; // Was the last operation successful?
switch ($mode) {
case 0 : // attribute name, href for instance
if ( preg_match('/^([-a-zA-Z:]+)/', $attr, $match ) ) {
$attrname = $match[1];
$working = $mode = 1;
$attr = preg_replace( '/^[-a-zA-Z:]+/', '', $attr );
}
break;
case 1 : // equals sign or valueless ("selected")
if (preg_match('/^\s*=\s*/', $attr)) // equals sign
{
$working = 1;
$mode = 2;
$attr = preg_replace('/^\s*=\s*/', '', $attr);
break;
}
if (preg_match('/^\s+/', $attr)) // valueless
{
$working = 1;
$mode = 0;
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y');
}
$attr = preg_replace('/^\s+/', '', $attr);
}
break;
case 2 : // attribute value, a URL after href= for instance
if (preg_match('%^"([^"]*)"(\s+|/?$)%', $attr, $match))
// "value"
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n');
}
$working = 1;
$mode = 0;
$attr = preg_replace('/^"[^"]*"(\s+|$)/', '', $attr);
break;
}
if (preg_match("%^'([^']*)'(\s+|/?$)%", $attr, $match))
// 'value'
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname='$thisval'", 'vless' => 'n');
}
$working = 1;
$mode = 0;
$attr = preg_replace("/^'[^']*'(\s+|$)/", '', $attr);
break;
}
if (preg_match("%^([^\s\"']+)(\s+|/?$)%", $attr, $match))
// value
{
$thisval = $match[1];
if ( in_array(strtolower($attrname), $uris) )
$thisval = wp_kses_bad_protocol($thisval, $allowed_protocols);
if(false === array_key_exists($attrname, $attrarr)) {
$attrarr[$attrname] = array ('name' => $attrname, 'value' => $thisval, 'whole' => "$attrname=\"$thisval\"", 'vless' => 'n');
}
// We add quotes to conform to W3C's HTML spec.
$working = 1;
$mode = 0;
$attr = preg_replace("%^[^\s\"']+(\s+|$)%", '', $attr);
}
break;
} // switch
if ($working == 0) // not well formed, remove and try again
{
$attr = wp_kses_html_error($attr);
$mode = 0;
}
} // while
if ($mode == 1 && false === array_key_exists($attrname, $attrarr))
// special case, for when the attribute list ends with a valueless
// attribute like "selected"
$attrarr[$attrname] = array ('name' => $attrname, 'value' => '', 'whole' => $attrname, 'vless' => 'y');
return $attrarr;
}
/**
* Finds all attributes of an HTML element.
*
* Does not modify input. May return "evil" output.
*
* Based on wp_kses_split2() and wp_kses_attr()
*
* @since 4.2.3
*
* @param string $element HTML element/tag
* @return array|bool List of attributes found in $element. Returns false on failure.
*/
function wp_kses_attr_parse( $element ) {
$valid = preg_match('%^(<\s*)(/\s*)?([a-zA-Z0-9]+\s*)([^>]*)(>?)$%', $element, $matches);
if ( 1 !== $valid ) {
return false;
}
$begin = $matches[1];
$slash = $matches[2];
$elname = $matches[3];
$attr = $matches[4];
$end = $matches[5];
if ( '' !== $slash ) {
// Closing elements do not get parsed.
return false;
}
// Is there a closing XHTML slash at the end of the attributes?
if ( 1 === preg_match( '%\s*/\s*$%', $attr, $matches ) ) {
$xhtml_slash = $matches[0];
$attr = substr( $attr, 0, -strlen( $xhtml_slash ) );
} else {
$xhtml_slash = '';
}
// Split it
$attrarr = wp_kses_hair_parse( $attr );
if ( false === $attrarr ) {
return false;
}
// Make sure all input is returned by adding front and back matter.
array_unshift( $attrarr, $begin . $slash . $elname );
array_push( $attrarr, $xhtml_slash . $end );
return $attrarr;
}
/**
* Builds an attribute list from string containing attributes.
*
* Does not modify input. May return "evil" output.
* In case of unexpected input, returns false instead of stripping things.
*
* Based on wp_kses_hair() but does not return a multi-dimensional array.
*
* @since 4.2.3
*
* @param string $attr Attribute list from HTML element to closing HTML element tag
* @return array|bool List of attributes found in $attr. Returns false on failure.
*/
function wp_kses_hair_parse( $attr ) {
if ( '' === $attr ) {
return array();
}
$regex =
'(?:'
. '[-a-zA-Z:]+' // Attribute name.
. '|'
. '\[\[?[^\[\]]+\]\]?' // Shortcode in the name position implies unfiltered_html.
. ')'
. '(?:' // Attribute value.
. '\s*=\s*' // All values begin with '='
. '(?:'
. '"[^"]*"' // Double-quoted
. '|'
. "'[^']*'" // Single-quoted
. '|'
. '[^\s"\']+' // Non-quoted
. '(?:\s|$)' // Must have a space
. ')'
. '|'
. '(?:\s|$)' // If attribute has no value, space is required.
. ')'
. '\s*'; // Trailing space is optional except as mentioned above.
// Although it is possible to reduce this procedure to a single regexp,
// we must run that regexp twice to get exactly the expected result.
$validation = "%^($regex)+$%";
$extraction = "%$regex%";
if ( 1 === preg_match( $validation, $attr ) ) {
preg_match_all( $extraction, $attr, $attrarr );
return $attrarr[0];
} else {
return false;
}
}
/**
* Performs different checks for attribute values.
*
* The currently implemented checks are "maxlen", "minlen", "maxval", "minval"
* and "valueless".
*
* @since 1.0.0
*
* @param string $value Attribute value
* @param string $vless Whether the value is valueless. Use 'y' or 'n'
* @param string $checkname What $checkvalue is checking for.
* @param mixed $checkvalue What constraint the value should pass
* @return bool Whether check passes
*/
function wp_kses_check_attr_val($value, $vless, $checkname, $checkvalue) {
$ok = true;
switch (strtolower($checkname)) {
case 'maxlen' :
// The maxlen check makes sure that the attribute value has a length not
// greater than the given value. This can be used to avoid Buffer Overflows
// in WWW clients and various Internet servers.
if (strlen($value) > $checkvalue)
$ok = false;
break;
case 'minlen' :
// The minlen check makes sure that the attribute value has a length not
// smaller than the given value.
if (strlen($value) < $checkvalue)
$ok = false;
break;
case 'maxval' :
// The maxval check does two things: it checks that the attribute value is
// an integer from 0 and up, without an excessive amount of zeroes or
// whitespace (to avoid Buffer Overflows). It also checks that the attribute
// value is not greater than the given value.
// This check can be used to avoid Denial of Service attacks.
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
$ok = false;
if ($value > $checkvalue)
$ok = false;
break;
case 'minval' :
// The minval check makes sure that the attribute value is a positive integer,
// and that it is not smaller than the given value.
if (!preg_match('/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value))
$ok = false;
if ($value < $checkvalue)
$ok = false;
break;
case 'valueless' :
// The valueless check makes sure if the attribute has a value
// (like ) or not (