Ticket #43187: 42770.diff

src/wp-includes/default-filters.php

@@ -118 +118 @@
         add_filter( $filter, 'balanceTags', 50 );
 }
 
+// Add proper rel values for links with target.
+foreach ( array(
+        'title_save_pre',
+        'content_save_pre',
+        'excerpt_save_pre',
+        'content_filtered_save_pre',
+        'pre_comment_content',
+        'pre_term_description',
+        'pre_link_description',
+        'pre_link_notes',
+        'pre_user_description',
+) as $filter ) {
+        add_filter( $filter, 'wp_targeted_link_rel' );
+};
+
 // Format strings for display.
 foreach ( array( 'comment_author', 'term_name', 'link_name', 'link_description', 'link_notes', 'bloginfo', 'wp_title', 'widget_title' ) as $filter ) {
         add_filter( $filter, 'wptexturize'   );

src/wp-includes/formatting.php

@@ -2773 +2773 @@
         return "<a $text rel=\"$rel\">";
 }
 
+/**
+ * Adds rel noreferrer and noopener to all HTML A elements that have a target.
+ *
+ * @param string $text Content that may contain HTML A elements.
+ * @return string Converted content.
+ */
+function wp_targeted_link_rel( $text ) {
+        // Don't run (more expensive) regex if no links with targets.
+        if ( stripos( $text, 'target' ) !== false && stripos( $text, '<a ' ) !== false ) {
+                $text = preg_replace_callback( '|<a\s([^>]*target\s*=[^>]*)>|i', 'wp_targeted_link_rel_callback', $text );
+        }
+
+        return $text;
+}
+
+/**
+ * Callback to add rel="noreferrer noopener" string to HTML A element.
+ *
+ * Will not duplicate existing noreferrer and noopener values
+ * to prevent from invalidating the HTML.
+ *
+ * @param array $matches Single Match
+ * @return string HTML A Element with rel noreferrer noopener in addition to any existing values
+ */
+function wp_targeted_link_rel_callback( $matches ) {
+        $link_html = $matches[1];
+        $rel_match = array();
+
+        /**
+         * Filters the rel values that are added to links with `target` attribute.
+         *
+         * @since 5.0.0
+         *
+         * @param string The rel values.
+         * @param string $link_html The matched content of the link tag including all HTML attributes.
+         */
+        $rel = apply_filters( 'wp_targeted_link_rel', 'noopener noreferrer', $link_html );
+
+        // Value with delimiters, spaces around are optional.
+        $attr_regex = '|rel\s*=\s*?(\\\\{0,1}["\'])(.*?)\\1|i';
+        preg_match( $attr_regex, $link_html, $rel_match );
+
+        if ( empty( $rel_match[0] ) ) {
+                // No delimiters, try with a single value and spaces, because `rel =  va"lue` is totally fine...
+                $attr_regex = '|rel\s*=(\s*)([^\s]*)|i';
+                preg_match( $attr_regex, $link_html, $rel_match );
+        }
+
+        if ( ! empty( $rel_match[0] ) ) {
+                $parts = preg_split( '|\s+|', strtolower( $rel_match[2] ) );
+                $parts = array_map( 'esc_attr', $parts );
+                $needed = explode( ' ', $rel );
+                $parts = array_unique( array_merge( $parts, $needed ) );
+                $delimiter = trim( $rel_match[1] ) ? $rel_match[1] : '"';
+                $rel = 'rel=' . $delimiter . trim( implode( ' ', $parts ) ) . $delimiter;
+                $link_html = str_replace( $rel_match[0], $rel, $link_html );
+        } else {
+                $link_html .= " rel=\"$rel\"";
+        }
+
+        return "<a $link_html>";
+}
+
 /**
  * Convert one smiley code to the icon graphic file equivalent.
  *

tests/phpunit/tests/rest-api/rest-attachments-controller.php

@@ -939 +939 @@
                                                 'rendered' => '<a href="#">link</a>',
                                         ),
                                         'description' => array(
-                                                'raw'      => '<a href="#" target="_blank">link</a>',
-                                                'rendered' => '<p><a href="#" target="_blank">link</a></p>',
+                                                'raw'      => '<a href="#" target="_blank" rel="noopener noreferrer">link</a>',
+                                                'rendered' => '<p><a href="#" target="_blank" rel="noopener noreferrer">link</a></p>',
                                         ),
                                         'caption' => array(
-                                                'raw'      => '<a href="#" target="_blank">link</a>',
-                                                'rendered' => '<p><a href="#" target="_blank">link</a></p>',
+                                                'raw'      => '<a href="#" target="_blank" rel="noopener noreferrer">link</a>',
+                                                'rendered' => '<p><a href="#" target="_blank" rel="noopener noreferrer">link</a></p>',
                                         ),
                                 )
                         ),

tests/phpunit/tests/rest-api/rest-posts-controller.php

@@ -2924 +2924 @@
                                                 'rendered' => '<a href="#">link</a>',
                                         ),
                                         'content' => array(
-                                                'raw'      => '<a href="#" target="_blank">link</a>',
-                                                'rendered' => '<p><a href="#" target="_blank">link</a></p>',
+                                                'raw'      => '<a href="#" target="_blank" rel="noopener noreferrer">link</a>',
+                                                'rendered' => '<p><a href="#" target="_blank" rel="noopener noreferrer">link</a></p>',
                                         ),
                                         'excerpt' => array(
-                                                'raw'      => '<a href="#" target="_blank">link</a>',
-                                                'rendered' => '<p><a href="#" target="_blank">link</a></p>',
+                                                'raw'      => '<a href="#" target="_blank" rel="noopener noreferrer">link</a>',
+                                                'rendered' => '<p><a href="#" target="_blank" rel="noopener noreferrer">link</a></p>',
                                         ),
                                 )
                         ),