From 8c7b4391a7ec6497710bb45665f97d020c4a8a7b Mon Sep 17 00:00:00 2001
From: hackademix <giorgio@maone.net>
Date: Mar 27 2023 20:45:35 +0000
Subject: Bug 41: Prevent NBS from leaking IPs through DNS for proxy requests.


---

diff --git a/firefox/http_shield_firefox.js b/firefox/http_shield_firefox.js
index 56e5459..4b3bf69 100644
--- a/firefox/http_shield_firefox.js
+++ b/firefox/http_shield_firefox.js
@@ -65,6 +65,9 @@ async function beforeSendHeadersListener(requestDetail)
 	var sourceResolution = "";
 	var blockNotifications = false;
 
+	const {proxyInfo} = requestDetail; // see https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/proxy/ProxyInfo
+	const dnsAllowed = !(proxyInfo && (proxyInfo.type && proxyInfo.type.startsWith("http") || proxyInfo.proxyDNS));
+
 	//Host found among user's trusted hosts, allow it right away
 	if (isNbsWhitelisted(sourceDomain))
 	{
@@ -90,9 +93,9 @@ async function beforeSendHeadersListener(requestDetail)
 			isSourcePrivate = true;
 		}
 	}
-	else //SOURCE is hostname
-	{
-		//Resoluting DNS query for source domain
+	else if (dnsAllowed) //SOURCE is hostname
+ 	{
+		//Resolving DNS query for source domain
 		sourceResolution = browser.dns.resolve(fullSourceDomain).then((val) =>
 		{
 			//Assigning source IPs
@@ -143,9 +146,9 @@ async function beforeSendHeadersListener(requestDetail)
 			}
 		}
 	}
-	else //Target is hostname
+	else if (dnsAllowed) //Target is hostname
 	{
-		//Resoluting DNS query for destination domain
+		//Resolving DNS query for destination domain
 		destinationResolution = browser.dns.resolve(fullTargetDomain).then((val) =>
 		{
 			//Assigning source IPs