From c143ded7584d4af739ae410a793d33e087745dcc Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Sun, 11 Dec 2022 11:30:09 -0500
Subject: [PATCH] Improve same-origin test for CNAME-uncloaking purpose

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1062

Related feedback:
- https://github.com/gorhill/uBlock/commit/161a175bb0596ed6b7734dd7ff77e85204603e96#commitcomment-90926455
---
 platform/firefox/vapi-background-ext.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/platform/firefox/vapi-background-ext.js b/platform/firefox/vapi-background-ext.js
index b4569f41c..6ec1a0108 100644
--- a/platform/firefox/vapi-background-ext.js
+++ b/platform/firefox/vapi-background-ext.js
@@ -256,13 +256,14 @@ vAPI.Net = class extends vAPI.Net {
                 return r;
             }
         }
-        const isRootDocument = details.type === 'main_frame' &&
-            this.cnameIgnoreRootDocument;
         const hn = hostnameFromNetworkURL(details.url);
         const cnRecord = this.cnames.get(hn);
         if ( cnRecord !== undefined ) {
             return this.processCanonicalName(hn, cnRecord, details);
         }
+        const documentUrl = details.documentUrl || details.url;
+        const isRootDocument = this.cnameIgnoreRootDocument &&
+            hn === hostnameFromNetworkURL(documentUrl);
         return browser.dns.resolve(hn, [ 'canonical_name' ]).then(
             rec => {
                 const cnRecord = this.recordCanonicalName(hn, rec, isRootDocument);