Ticket #33121: 33121.5.diff

src/wp-includes/kses.php

@@ -864 +864 @@
  * @return bool Is the attribute allowed?
  */
 function wp_kses_attr_check( &$name, &$value, &$whole, $vless, $element, $allowed_html ) {
-        $allowed_attr = $allowed_html[strtolower( $element )];
+        $allowed_attr = $allowed_html[ strtolower( $element ) ];
 
         $name_low = strtolower( $name );
+
         if ( ! isset( $allowed_attr[$name_low] ) || '' == $allowed_attr[$name_low] ) {
-                $name = $value = $whole = '';
-                return false;
+                // Allow `data-*` attributes.
+                // When specifying `$allowed_html`, the attribute name should be set as `data-*`
+                // (not to be mixed with the HTML 4.0 `data` attribute, see https://www.w3.org/TR/html40/struct/objects.html#adef-data).
+                // Note: the attribute name should only contain `A-Za-z0-9_-` chars.
+                if ( strpos( $name_low, 'data-' ) === 0 && ! empty( $allowed_attr['data-*'] ) && preg_match( '/^data(?:-[a-z0-9_]+)+$/', $name_low, $match ) ) {
+                        // Add the whole attribute name to the allowed attributes and set any restrictions
+                        // for the `data-*` attribute values for the current element.
+                        $allowed_attr[ $match[0] ] = $allowed_attr['data-*'];
+                } else {
+                        $name = $value = $whole = '';
+                        return false;
+                }
         }
 
         if ( 'style' == $name_low ) {
@@ -884 +895 @@
                 $value = $new_value;
         }
 
-        if ( is_array( $allowed_attr[$name_low] ) ) {
+        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 ) ) {
@@ -1820 +1831 @@
                 'style' => true,
                 'title' => true,
                 'role' => true,
+                'data-*' => true,
         );
 
         if ( true === $value )

tests/phpunit/tests/kses.php

@@ -718 +718 @@
 
                 $this->assertEquals( "<{$element}>", wp_kses_attr( $element, $attribute, array( 'foo' => false ), array() ) );
         }
+
+        /**
+         * Data attributes are globally accepted.
+         *
+         * @ticket 33121
+         */
+        function test_wp_kses_attr_data_attribute_is_allowed() {
+                $test = '<div data-foo="foo" data-bar="bar" datainvalid="gone" data--invaild="gone"  data-also-invaild-="gone" data-two-hyphens="remains">Pens and pencils</div>';
+                $expected = '<div data-foo="foo" data-bar="bar" data-two-hyphens="remains">Pens and pencils</div>';
+
+                $this->assertEquals( $expected, wp_kses_post( $test ) );
+        }
+
+        /**
+         * Ensure wildcard attributes block unprefixed wildcard uses.
+         *
+         * @ticket 33121
+         */
+        function test_wildcard_requires_hyphen_after_prefix() {
+                $allowed_html = array(
+                        'div' => array(
+                                'data-*' => true,
+                                'on-*' => true,
+                        ),
+                );
+
+                $string = '<div datamelformed-prefix="gone" data="gone" data-="gone" onclick="alert(1)">Malformed attributes</div>';
+                $expected = '<div>Malformed attributes</div>';
+
+                $actual = wp_kses( $string, $allowed_html );
+
+                $this->assertSame( $expected, $actual );
+        }
+
+        /**
+         * Ensure wildcard allows two hyphen.
+         *
+         * @ticket 33121
+         */
+        function test_wildcard_allows_two_hyphens() {
+                $allowed_html = array(
+                        'div' => array(
+                                'data-*' => true,
+                        ),
+                );
+
+                $string = '<div data-wp-id="pens-and-pencils">Well formed attribute</div>';
+                $expected = '<div data-wp-id="pens-and-pencils">Well formed attribute</div>';
+
+                $actual = wp_kses( $string, $allowed_html );
+
+                $this->assertSame( $expected, $actual );
+        }
+
+        /**
+         * Ensure wildcard attributes only support valid prefixes.
+         *
+         * @dataProvider data_wildcard_attribute_prefixes
+         *
+         * @ticket 33121
+         */
+        function test_wildcard_attribute_prefixes( $wildcard_attribute, $expected ) {
+                $allowed_html = array(
+                        'div' => array(
+                                $wildcard_attribute => true,
+                        ),
+                );
+
+                $name = str_replace( '*', strtolower( __FUNCTION__ ), $wildcard_attribute );
+                $value = __FUNCTION__;
+                $whole = "{$name}=\"{$value}\"";
+
+                $actual = wp_kses_attr_check( $name, $value, $whole, 'n', 'div', $allowed_html );
+
+                $this->assertSame( $expected, $actual );
+        }
+
+        /**
+         * @return array Array of arguments for wildcard testing
+         *               [0] The prefix being tested.
+         *               [1] The outcome of `wp_kses_attr_check` for the prefix.
+         */
+        function data_wildcard_attribute_prefixes() {
+                return array(
+                        // Ends correctly
+                        array( 'data-*', true ),
+
+                        // Does not end with trialing `-`.
+                        array( '33121*', false ),
+
+                        // Multiple wildcards.
+                        array( '3*121-*', false ),
+                        array( '33121**', false ),
+                );
+        }
 }