Changeset 33360 for branches/4.2/src/wp-includes/kses.php

Timestamp:

07/22/2015 05:43:35 AM (9 years ago)

Author:

pento

Message:

Shortcodes: Improve the reliablity of shortcodes inside HTML tags.

Merge of [33359] to the 4.2 branch.

Props miqrogroove.

See #15694.

File:

• branches/4.2/src/wp-includes/kses.php (modified) (4 diffs)

branches/4.2/src/wp-includes/kses.php

@@ -530 +530 @@
 
 /**
+ * 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.
  *
@@ -749 +825 @@
     // in $attr2
     $attr2 = '';
-
-    $allowed_attr = $allowed_html[strtolower($element)];
-    foreach ($attrarr as $arreach) {
-        if ( ! isset( $allowed_attr[strtolower($arreach['name'])] ) )
-            continue; // the attribute is not allowed
-
-        $current = $allowed_attr[strtolower($arreach['name'])];
-        if ( $current == '' )
-            continue; // the attribute is not allowed
-
-        if ( strtolower( $arreach['name'] ) == 'style' ) {
-            $orig_value = $arreach['value'];
-            $value = safecss_filter_attr( $orig_value );
-
-            if ( empty( $value ) )
-                continue;
-
-            $arreach['value'] = $value;
-            $arreach['whole'] = str_replace( $orig_value, $value, $arreach['whole'] );
+    foreach ( $attrarr as $arreach ) {
+        if ( wp_kses_attr_check( $arreach['name'], $arreach['value'], $arreach['whole'], $arreach['vless'], $element, $allowed_html ) ) {
+            $attr2 .= ' '.$arreach['whole'];
         }
-
-        if ( ! is_array($current) ) {
-            $attr2 .= ' '.$arreach['whole'];
-        // there are no checks
-
-        } 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 ( $ok )
-                $attr2 .= ' '.$arreach['whole']; // it passed them
-        } // if !is_array($current)
-    } // foreach
+    }
 
     // Remove any "<" or ">" characters
@@ -793 +835 @@
 
     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;
 }
 
@@ -922 +1011 @@
 
     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;
+    }
 }