Ticket #35274: 35274.2.diff

src/wp-admin/includes/network.php

@@ -27 +27 @@
 }
 
 /**
- * Allow subdomain install
+ * Allow subdomain install.
  *
  * @since 3.0.0
- * @return bool Whether subdomain install is allowed
+ *
+ * @return bool Whether a subdomain install is allowed.
  */
 function allow_subdomain_install() {
-        $domain = preg_replace( '|https?://([^/]+)|', '$1', get_option( 'home' ) );
-        if ( parse_url( get_option( 'home' ), PHP_URL_PATH ) || 'localhost' == $domain || preg_match( '|^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$|', $domain ) )
+        $home   = get_option( 'home' );
+        $domain = preg_replace( '|^https?://([^/]+)|', '$1', $home );
+
+        // The site isn't at the root of the domain.
+        if ( parse_url( $home, PHP_URL_PATH ) ) {
                 return false;
 
+        // "localhost" is a reserved domain.
+        } elseif ( 'localhost' === $domain ) {
+                return false;
+
+        // IP addresses do not permit subdomains.
+        } elseif ( preg_match( '|^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$|', $domain ) ) {
+                return false;
+        }
+
         return true;
 }
 
@@ -159 +172 @@
                 $subdomain_install = true;
         } else {
                 $subdomain_install = false;
-                if ( $got_mod_rewrite = got_mod_rewrite() ) { // dangerous assumptions 
+                if ( $got_mod_rewrite = got_mod_rewrite() ) { // dangerous assumptions
                         echo '<div class="updated inline"><p><strong>' . __( 'Note:' ) . '</strong> ';
                         /* translators: %s: mod_rewrite */
                         printf( __( 'Please make sure the Apache %s module is installed as it will be used at the end of this installation.' ),

tests/phpunit/tests/multisite/allowSubdomainInstall.php

@@ +1 @@
+<?php
+
+// This file is not normally loaded for unit tests.
+require_once ABSPATH . '/wp-admin/includes/network.php';
+
+/**
+ * @group multisite
+ */
+class Tests_Multisite_AllowSubdomainInstall extends WP_UnitTestCase {
+
+        public function test_allow_subdomain_install_with_regular_domain() {
+                update_option( 'home', 'http://example.com' );
+
+                $this->assertTrue( allow_subdomain_install() );
+        }
+
+        public function test_allow_subdomain_install_with_https_domain() {
+                update_option( 'home', 'https://example.com' );
+
+                $this->assertTrue( allow_subdomain_install() );
+        }
+
+        public function test_allow_subdomain_install_within_remote_path() {
+                update_option( 'home', 'http://example.com/mysite' );
+
+                $this->assertFalse( allow_subdomain_install() );
+        }
+
+        public function test_allow_subdomain_install_with_localhost() {
+                update_option( 'home', 'http://localhost' );
+
+                $this->assertFalse( allow_subdomain_install() );
+        }
+
+        public function test_allow_subdomain_install_with_ip_address() {
+                update_option( 'home', 'http://192.168.1.1' );
+
+                $this->assertFalse( allow_subdomain_install() );
+        }
+}