Ticket #37134: 37134.7.diff

src/wp-includes/kses.php

@@ -2301 +2301 @@
                         }
                 }
 
-                // Remove any CSS containing containing \ ( & } = or comments, except for url() useage checked above.
-                if ( $found && ! preg_match( '%[\\\(&=}]|/\*%', $css_test_string ) ) {
-                        if ( '' !== $css ) {
-                                $css .= ';';
+                if ( $found ) {
+                        /**
+                         * Filters the regex limiting the list of characters not allowed in CSS rules.
+                         *
+                         * Default behaviour is to remove any css containing \ ( & } = or comments, except for url() usage.
+                         *
+                         * @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.
+                         */
+                        $disallowed_chars = apply_filters( 'safe_style_disallowed_chars', '%[\\\(&=}]|/\*%', $css_test_string );
+                        if ( ! preg_match( $disallowed_chars, $css_test_string ) ) {
+                                if ( '' !== $css ) {
+                                        $css .= ';';
+                                }
+                                $css .= $css_item;
                         }
-
-                        $css .= $css_item;
                 }
         }
 

tests/phpunit/tests/kses.php

@@ -1002 +1002 @@
                                 'css'      => 'background: conic-gradient(at 0% 30%, red 10%, yellow 30%, #1e90ff 50%)',
                                 'expected' => 'background: conic-gradient(at 0% 30%, red 10%, yellow 30%, #1e90ff 50%)',
                         ),
-
+                        // Expressions are not allowed.
+                        array(
+                                'css'      => 'height: expression( body.scrollTop + 50 + "px" )',
+                                'expected' => '',
+                        ),
+                        // RGB color values are not allowed.
+                        array(
+                                'css'      => 'color: rgb( 100, 100, 100 )',
+                                'expected' => '',
+                        ),
+                        // RGBA color values are not allowed.
+                        array(
+                                'css'      => 'color: rgb( 100, 100, 100, .4 )',
+                                'expected' => '',
+                        ),
                 );
         }
 
@@ -1247 +1261 @@
                         ),
                 );
         }
+
+        /**
+         * 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.
+         *
+         * @ticket 37134
+         *
+         * @dataProvider data_test_safecss_filter_attr_filtered
+         *
+         * @param string $css      A string of CSS rules.
+         * @param string $expected Expected string of CSS rules.
+         */
+        public function test_safecss_filter_attr_filtered( $css, $expected ) {
+                add_filter( 'safe_style_disallowed_chars', array( $this, '_safe_style_disallowed_chars_filter' ) );
+                $this->assertSame( $expected, safecss_filter_attr( $css ) );
+                remove_filter( 'safe_style_disallowed_chars', array( $this, '_safe_style_disallowed_chars_filter' ) );
+        }
+
+        /**
+         * Data Provider for test_safecss_filter_attr_filtered().
+         *
+         * @return array {
+         *     @type array {
+         *         @string string $css      A string of CSS rules.
+         *         @string string $expected Expected string of CSS rules.
+         *     }
+         * }
+         */
+        public function data_test_safecss_filter_attr_filtered() {
+                return array(
+
+                        // A single attribute name, with a single value.
+                        array(
+                                'css'      => 'margin-top: 2px',
+                                'expected' => 'margin-top: 2px',
+                        ),
+                        // Backslash \ can be allowed with the 'safe_style_disallowed_chars' filter.
+                        array(
+                                'css'      => 'margin-top: \2px',
+                                'expected' => 'margin-top: \2px',
+                        ),
+                        // Curly bracket } can be allowed with the 'safe_style_disallowed_chars' filter.
+                        array(
+                                'css'      => 'margin-bottom: 2px}',
+                                'expected' => 'margin-bottom: 2px}',
+                        ),
+                        // Parenthesis ) can be allowed with the 'safe_style_disallowed_chars' filter.
+                        array(
+                                'css'      => 'margin-bottom: 2px)',
+                                'expected' => 'margin-bottom: 2px)',
+                        ),
+                        // Ampersand & can be allowed with the 'safe_style_disallowed_chars' filter.
+                        array(
+                                'css'      => 'margin-bottom: 2px&',
+                                'expected' => 'margin-bottom: 2px&',
+                        ),
+                        // Expressions can be allowed with the 'safe_style_disallowed_chars' 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.
+                        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.
+                        array(
+                                'css'      => 'color: rgb( 100, 100, 100, .4 )',
+                                'expected' => 'color: rgb( 100, 100, 100, .4 )',
+                        ),
+                );
+        }
 }