Added support for a Header to indicating the request has already been proxied though upward-php

Author: chorgues

Plugin/Magento/Framework/App/AreaList.php

@@ -1,4 +1,5 @@
 <?php
+
 /**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
@@ -10,10 +11,15 @@
 use Magento\Framework\App\Config\ScopeConfigInterface;
 use Magento\Framework\App\ObjectManager;
 use Magento\Store\Model\ScopeInterface;
+use Magento\Upward\Resolver\Proxy;
 use Magento\UpwardConnector\Api\UpwardPathManagerInterface;
 
 class AreaList
 {
+    public const UPWARD_HEADER = 'UpwardProxied';
+
+    public const UPWARD_ENV_HEADER = 'UPWARD_PHP_PROXY_HEADER';
+
     /**
      * @var ScopeConfigInterface
      */
@@ -56,7 +62,6 @@ public function afterGetCodeByFrontName(
         $result,
         $frontName
     ) {
-
         if ($result !== 'frontend') {
             return $result;
         }
@@ -73,6 +78,14 @@ public function afterGetCodeByFrontName(
             ) ?? ''
         );
 
+        $request = new \Laminas\Http\PhpEnvironment\Request();
+        $upwardProxyEnv = getenv(self::UPWARD_ENV_HEADER);
+
+        /** $upwardProxyEnv needs to be truthy because getenv returns "false" if it didn't find it */
+        if ($upwardProxyEnv && $request->getHeader(self::UPWARD_HEADER) === $upwardProxyEnv) {
+            return $result;
+        }
+
         if ($frontName && in_array($frontName, $frontNamesToSkip)) {
             return $result;
         }

README.md

@@ -19,6 +19,20 @@ The Magento 2 UPWARD connector has additional settings that can be configured in
 
 These are the configurations for the UPWARD process itself.
 
+#### UPWARD Environment variable
+
+This environment variable is meant to allow a secure way for Magento2 to distinguish a request which went through the UPWARD Proxy, and a "natural" request.
+
+```
+# bash
+export UPWARD_PHP_PROXY_HEADER='arbitrary_security_string' # preferably random, unique and longer than 16 characters
+
+# nginx conf
+fastcgi_param  UPWARD_PHP_PROXY_HEADER "arbitrary_security_string";
+
+```
+
+
 #### UPWARD Config File
 
 This configuration is the location of the UPWARD configuration file for the UPWARD-PHP server.