Changeset 48086

Timestamp:

06/18/2020 08:59:43 PM (4 years ago)

Author:

adamsilverstein

Message:

Formatting: new filter safecss_filter_attr_allow_css on css parts.

Enables developers to determine whether a section of CSS should be allowed or discarded. By default, the value will be false if the part contains \ ( & } = or comments. Returning true allows the CSS part to be included in the output.

Replaces the safe_style_disallowed_chars filter introduced in r47891.

Props azaozz.
Fixes #37134.

Location:

trunk

Files:

• src/wp-includes/kses.php (modified) (1 diff)
• tests/phpunit/tests/kses.php (modified) (3 diffs)

trunk/src/wp-includes/kses.php

@@ -2358 +2358 @@
 
         if ( $found ) {
+            // Check for any CSS containing \ ( & } = or comments, except for url() usage checked above.
+            $allow_css = ! preg_match( '%[\\\(&=}]|/\*%', $css_test_string );
+
             /**
-             * Filters the regex limiting the list of characters not allowed in CSS rules.
+             * Filters the check for unsafe CSS in `safecss_filter_attr`.
              *
-             * Default behaviour is to remove any CSS containing \ ( & } = or comments,
-             * except for url() usage.
+             * Enables developers to determine whether a section of CSS should be allowed or discarded.
+             * By default, the value will be false if the part contains \ ( & } = or comments.
+             * Return true to allow the CSS part to be included in the output.
              *
              * @since 5.5.0
              *
-             * @param string $regex           Regex pattern of disallowed characters in CSS rules.
-             *                                Default is '%[\\\(&=}]|/\*%'.
-             * @param string $css_test_string CSS value to test.
+             * @param bool   $allow_css       Whether the CSS in the test string is considered safe.
+             * @param string $css_test_string The css string to test.
              */
-            $disallowed_chars = apply_filters( 'safe_style_disallowed_chars', '%[\\\(&=}]|/\*%', $css_test_string );
-            if ( ! preg_match( $disallowed_chars, $css_test_string ) ) {
+            $allow_css = apply_filters( 'safecss_filter_attr_allow_css', $allow_css, $css_test_string );
+
+             // Only add the css part if it passes the regex check.
+            if ( $allow_css ) {
                 if ( '' !== $css ) {
                     $css .= ';';
                 }
+
                 $css .= $css_item;
             }

trunk/tests/phpunit/tests/kses.php

@@ -1264 +1264 @@
 
     /**
-     * Filter for disallowed characters never matches thus allowing all characters.
-     */
-    function _safe_style_disallowed_chars_filter( $regex ) {
-        return '%a^%'; // Regex with no matches.
-
-    }
-    /**
-     * Testing the safecss_filter_attr() function with the safe_style_disallowed_chars filter.
+     * Testing the safecss_filter_attr() function with the safecss_filter_attr_allow_css filter.
      *
      * @ticket 37134
@@ -1281 +1274 @@
      */
     public function test_safecss_filter_attr_filtered( $css, $expected ) {
-        add_filter( 'safe_style_disallowed_chars', array( $this, '_safe_style_disallowed_chars_filter' ) );
+        add_filter( 'safecss_filter_attr_allow_css', '__return_true' );
         $this->assertSame( $expected, safecss_filter_attr( $css ) );
-        remove_filter( 'safe_style_disallowed_chars', array( $this, '_safe_style_disallowed_chars_filter' ) );
+        remove_filter( 'safecss_filter_attr_allow_css', '__return_true' );
     }
 
@@ -1304 +1297 @@
                 'expected' => 'margin-top: 2px',
             ),
-            // Backslash \ can be allowed with the 'safe_style_disallowed_chars' filter.
+            // Backslash \ can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'margin-top: \2px',
                 'expected' => 'margin-top: \2px',
             ),
-            // Curly bracket } can be allowed with the 'safe_style_disallowed_chars' filter.
+            // Curly bracket } can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'margin-bottom: 2px}',
                 'expected' => 'margin-bottom: 2px}',
             ),
-            // Parenthesis ) can be allowed with the 'safe_style_disallowed_chars' filter.
+            // Parenthesis ) can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'margin-bottom: 2px)',
                 'expected' => 'margin-bottom: 2px)',
             ),
-            // Ampersand & can be allowed with the 'safe_style_disallowed_chars' filter.
+            // Ampersand & can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'margin-bottom: 2px&',
                 'expected' => 'margin-bottom: 2px&',
             ),
-            // Expressions can be allowed with the 'safe_style_disallowed_chars' filter.
+            // Expressions can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'height: expression( body.scrollTop + 50 + "px" )',
                 'expected' => 'height: expression( body.scrollTop + 50 + "px" )',
             ),
-            // RGB color values can be allowed with the 'safe_style_disallowed_chars' filter.
+            // RGB color values can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'color: rgb( 100, 100, 100 )',
                 'expected' => 'color: rgb( 100, 100, 100 )',
             ),
-            // RGBA color values can be allowed with the 'safe_style_disallowed_chars' filter.
+            // RGBA color values can be allowed with the 'safecss_filter_attr_allow_css' filter.
             array(
                 'css'      => 'color: rgb( 100, 100, 100, .4 )',