return wp_kses_split($string, $allowed_html, $allowed_protocols);
}
+/**
+ * Filters one attribute only and ensures its value is allowed.
+ *
+ * This function has the advantage of being more secure than esc_attr() and can
+ * escape data in some situations where wp_kses() must strip the whole attribute.
+ *
+ * @since 4.2.3
+ *
+ * @param string $string The 'whole' attribute, including name and value.
+ * @param string $element The element name to which the attribute belongs.
+ * @return string Filtered attribute.
+ */
+function wp_kses_one_attr( $string, $element ) {
+ $uris = array('xmlns', 'profile', 'href', 'src', 'cite', 'classid', 'codebase', 'data', 'usemap', 'longdesc', 'action');
+ $allowed_html = wp_kses_allowed_html( 'post' );
+ $allowed_protocols = wp_allowed_protocols();
+ $string = wp_kses_no_null( $string, array( 'slash_zero' => 'keep' ) );
+ $string = wp_kses_js_entities( $string );
+ $string = wp_kses_normalize_entities( $string );
+
+ // Preserve leading and trailing whitespace.
+ $matches = array();
+ preg_match('/^\s*/', $string, $matches);
+ $lead = $matches[0];
+ preg_match('/\s*$/', $string, $matches);
+ $trail = $matches[0];
+ if ( empty( $trail ) ) {
+ $string = substr( $string, strlen( $lead ) );
+ } else {
+ $string = substr( $string, strlen( $lead ), -strlen( $trail ) );
+ }
+
+ // Parse attribute name and value from input.
+ $split = preg_split( '/\s*=\s*/', $string, 2 );
+ $name = $split[0];
+ if ( count( $split ) == 2 ) {
+ $value = $split[1];
+
+ // Remove quotes surrounding $value.
+ // Also guarantee correct quoting in $string for this one attribute.
+ if ( '' == $value ) {
+ $quote = '';
+ } else {
+ $quote = $value[0];
+ }
+ if ( '"' == $quote || "'" == $quote ) {
+ if ( substr( $value, -1 ) != $quote ) {
+ return '';
+ }
+ $value = substr( $value, 1, -1 );
+ } else {
+ $quote = '"';
+ }
+
+ // Sanitize quotes and angle braces.
+ $value = htmlspecialchars( $value, ENT_QUOTES, null, false );
+
+ // Sanitize URI values.
+ if ( in_array( strtolower( $name ), $uris ) ) {
+ $value = wp_kses_bad_protocol( $value, $allowed_protocols );
+ }
+
+ $string = "$name=$quote$value$quote";
+ $vless = 'n';
+ } else {
+ $value = '';
+ $vless = 'y';
+ }
+
+ // Sanitize attribute by name.
+ wp_kses_attr_check( $name, $value, $string, $vless, $element, $allowed_html );
+
+ // Restore whitespace.
+ return $lead . $string . $trail;
+}
+
/**
* Return a list of allowed tags and attributes for a given context.
*
// 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'];
+ }
+ }
- $allowed_attr = $allowed_html[strtolower($element)];
- foreach ($attrarr as $arreach) {
- if ( ! isset( $allowed_attr[strtolower($arreach['name'])] ) )
- continue; // the attribute is not allowed
+ // Remove any "<" or ">" characters
+ $attr2 = preg_replace('/[<>]/', '', $attr2);
- $current = $allowed_attr[strtolower($arreach['name'])];
- if ( $current == '' )
- continue; // the attribute is not allowed
+ return "<$element$attr2$xhtml_slash>";
+}
- if ( strtolower( $arreach['name'] ) == 'style' ) {
- $orig_value = $arreach['value'];
- $value = safecss_filter_attr( $orig_value );
+/**
+ * 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 )];
- if ( empty( $value ) )
- continue;
+ $name_low = strtolower( $name );
+ if ( ! isset( $allowed_attr[$name_low] ) || '' == $allowed_attr[$name_low] ) {
+ $name = $value = $whole = '';
+ return false;
+ }
- $arreach['value'] = $value;
- $arreach['whole'] = str_replace( $orig_value, $value, $arreach['whole'] );
+ if ( 'style' == $name_low ) {
+ $new_value = safecss_filter_attr( $value );
+
+ if ( empty( $new_value ) ) {
+ $name = $value = $whole = '';
+ return false;
}
- if ( ! is_array($current) ) {
- $attr2 .= ' '.$arreach['whole'];
- // there are no checks
+ $whole = str_replace( $value, $new_value, $whole );
+ $value = $new_value;
+ }
- } else {
- // there are some checks
- $ok = true;
- foreach ($current as $currkey => $currval) {
- if ( ! wp_kses_check_attr_val($arreach['value'], $arreach['vless'], $currkey, $currval) ) {
- $ok = false;
- break;
- }
+ 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;
}
+ }
+ }
- if ( $ok )
- $attr2 .= ' '.$arreach['whole']; // it passed them
- } // if !is_array($current)
- } // foreach
-
- // Remove any "<" or ">" characters
- $attr2 = preg_replace('/[<>]/', '', $attr2);
-
- return "<$element$attr2$xhtml_slash>";
+ return true;
}
/**
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.
*
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