Ticket #15706: 15706.diff

wp-includes/ms-functions.php

@@ -504 +504 @@
         $limited_email_domains = get_site_option( 'limited_email_domains' );
         if ( is_array( $limited_email_domains ) && empty( $limited_email_domains ) == false ) {
                 $emaildomain = substr( $user_email, 1 + strpos( $user_email, '@' ) );
-                if ( in_array( $emaildomain, $limited_email_domains ) == false )
+                if ( ! apply_filters( 'limited_email_domains_check', in_array( $emaildomain, $limited_email_domains ), $emaildomain, $limited_email_domains )  )
                         $errors->add('user_email', __('Sorry, that email address is not allowed!'));
         }