From fae8ab9c7ce18b280c1d304112e11fa13166d195 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Gon=C3=A7alves?=
 <ricardobrg@users.noreply.github.com>
Date: Wed, 22 Aug 2018 01:22:01 -0300
Subject: [PATCH] Fix #1349 relative path issue in action

Detect if action URL in the form is relative and format it properly
---
 includes/sanitizers/class-amp-form-sanitizer.php | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/includes/sanitizers/class-amp-form-sanitizer.php b/includes/sanitizers/class-amp-form-sanitizer.php
index 05c6252f0cc..223cb826042 100644
--- a/includes/sanitizers/class-amp-form-sanitizer.php
+++ b/includes/sanitizers/class-amp-form-sanitizer.php
@@ -67,6 +67,11 @@ public function sanitize() {
 				$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . wp_unslash( $_SERVER['REQUEST_URI'] ) ); // WPCS: ignore. input var okay, sanitization ok.
 			} else {
 				$action_url = $node->getAttribute( 'action' );
+				//check if action_url is a relative path and add the host to it
+				preg_match('(^\/?[^\/].*)',$action_url,$matches);
+				if ($matches){
+					$action_url = '//' . $_SERVER['HTTP_HOST'] . $action_url;
+				}
 			}
 			$xhr_action = $node->getAttribute( 'action-xhr' );