Ticket #42609: 42609.1.patch

wp-admin/includes/file.php

@@ -385 +385 @@
                         return new WP_Error( 'invalid_plugin' );
                 }
 
-                if ( 0 !== validate_file( $file, get_plugin_files( $plugin ) ) ) {
+                if ( ! in_array( validate_file( $file, get_plugin_files( $plugin ) ), array( 0, 2 ) ) ) {
                         return new WP_Error( 'bad_plugin_file_path', __( 'Sorry, that file cannot be edited.' ) );
                 }
 
@@ -445 +445 @@
                         }
                 }
 
-                if ( 0 !== validate_file( $real_file, $allowed_files ) ) {
+                if ( ! in_array( validate_file( $real_file, $allowed_files ), array( 0, 2 ) ) ) {
                         return new WP_Error( 'disallowed_theme_file', __( 'Sorry, that file cannot be edited.' ) );
                 }