From d6e4c7c1ea77af7423369da84e2848f98726bb04 Mon Sep 17 00:00:00 2001
From: Luka Jeran <lukaw3d@gmail.com>
Date: Fri, 15 Oct 2021 05:01:36 +0200
Subject: [PATCH] Ignore messages other than from iframe parent

---
 mitm.html | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mitm.html b/mitm.html
index 04450a9..f3141dd 100644
--- a/mitm.html
+++ b/mitm.html
@@ -60,6 +60,11 @@
 function onMessage (event) {
   let { data, ports, origin } = event
 
+  // Ignore messages other than from iframe parent (e.g. extensions)
+  if (event.source !== window.parent) {
+    return
+  }
+  
   // It's important to have a messageChannel, don't want to interfere
   // with other simultaneous downloads
   if (!ports || !ports.length) {