Ticket #27317: 27317.7.patch

src/wp-admin/includes/user.php

@@ -142 +142 @@
         if ( !$update && username_exists( $user->user_login ) )
                 $errors->add( 'user_login', __( '<strong>ERROR</strong>: This username is already registered. Please choose another one.' ));
 
+        /** This filter is documented in wp-includes/user-functions.php */
+        $usernames = apply_filters( 'illegal_user_logins', array() );
+        if ( in_array( $user->user_login, $usernames ) ) {
+                $errors->add( 'illegal_user_login', __( '<strong>ERROR</strong>: Sorry, that username is not allowed.' ) );
+        }
+
         /* checking email address */
         if ( empty( $user->user_email ) ) {
                 $errors->add( 'empty_email', __( '<strong>ERROR</strong>: Please enter an email address.' ), array( 'form-field' => 'email' ) );

src/wp-includes/ms-functions.php

@@ -427 +427 @@
                 $illegal_names = array(  'www', 'web', 'root', 'admin', 'main', 'invite', 'administrator' );
                 add_site_option( 'illegal_names', $illegal_names );
         }
-        if ( in_array( $user_name, $illegal_names ) )
-                $errors->add('user_name',  __( 'That username is not allowed.' ) );
+        if ( in_array( $user_name, $illegal_names ) ) {
+                $errors->add( 'user_name',  __( 'Sorry, that username is not allowed.' ) );
+        }
 
+        /** This filter is documented in wp-includes/user-functions.php */
+        if ( in_array( $user_name, apply_filters( 'illegal_user_logins', array() ) ) ) {
+                $errors->add( 'user_name',  __( 'Sorry, that username is not allowed.' ) );
+        }
+
         if ( is_email_address_unsafe( $user_email ) )
                 $errors->add('user_email',  __('You cannot use that email address to signup. We are having problems with them blocking some of our email. Please use another email provider.'));
 

src/wp-includes/user-functions.php

@@ -1315 +1315 @@
                 return new WP_Error( 'existing_user_login', __( 'Sorry, that username already exists!' ) );
         }
 
+        /**
+         * Filter the list of blacklisted usernames.
+         *
+         * @since 4.4.0
+         *
+         * @param array $usernames Array of blacklisted usernames.
+         */
+        if ( in_array( $user_login, apply_filters( 'illegal_user_logins', array() ) ) ) {
+                return new WP_Error( 'illegal_user_login', __( 'Sorry, that username is not allowed.' ) );
+        }       
+
         /*
          * If a nicename is provided, remove unsafe user characters before using it.
          * Otherwise build a nicename from the user_login.

tests/phpunit/tests/user.php

@@ -600 +600 @@
         }
 
         /**
+         * @ticket 27317
+         */
+        function test_illegal_user_logins_single() {
+                $user_data = array(
+                        'user_login' => 'testuser',
+                        'user_email' => 'testuser@example.com',
+                        'user_pass'  => wp_generate_password(),
+                );
+
+                add_filter( 'illegal_user_logins', array( $this, '_illegal_user_logins' ) );
+
+                $response = wp_insert_user( $user_data );
+                $this->assertInstanceOf( 'WP_Error', $response );
+                $this->assertEquals( 'illegal_user_login', $response->get_error_code() );
+
+                remove_filter( 'illegal_user_logins', array( $this, '_illegal_user_logins' ) );
+
+                $user_id = wp_insert_user( $user_data );
+                $user = get_user_by( 'id', $user_id );
+                $this->assertInstanceOf( 'WP_User', $user );
+        }
+
+        /**
+         * @ticket 27317
+         */
+        function test_illegal_user_logins_multisite() {
+                if ( ! is_multisite() ) {
+                        return;
+                }
+
+                $user_data = array(
+                        'user_login' => 'testuser',
+                        'user_email' => 'testuser@example.com',
+                );
+
+                add_filter( 'illegal_user_logins', array( $this, '_illegal_user_logins' ) );
+
+                $response = wpmu_validate_user_signup( $user_data['user_login'], $user_data['user_email'] );
+                $this->assertInstanceOf( 'WP_Error', $response['errors'] );
+                $this->assertEquals( 'user_name', $response['errors']->get_error_code() );
+
+                remove_filter( 'illegal_user_logins', array( $this, '_illegal_user_logins' ) );
+
+                $response = wpmu_validate_user_signup( $user_data['user_login'], $user_data['user_email'] );
+                $this->assertInstanceOf( 'WP_Error', $response['errors'] );
+                $this->assertEquals( 0, count( $response['errors']->get_error_codes() ) );
+        }
+
+        function _illegal_user_logins() {
+                return array( 'testuser' );     
+        }
+
+        /**
          * @ticket 24618
          */
         public function test_validate_username_string() {