Sanitize connCheck URL

Author: ruihildt

src/helpers/socksProxy/socksProxy.ts

@@ -50,10 +50,12 @@ export const handleProxyRequest = async (details: browser.proxy._OnRequestDetail
 
     // 3. When the request if a conncheck/DNS check originating from the extension,
     // we want to use the same proxy as the active tab, to get a consistent conncheck result
-    const isExtensionRequest = details.documentUrl?.startsWith('moz-extension://');
-    const isConnCheck = details.url?.endsWith('am.i.mullvad.net/json');
-    const isDNSCheck = details.url?.endsWith('dnsleak.am.i.mullvad.net/');
+    const { domain: maybeMullvadDomain } = checkDomain(details.url);
+    const isMullvadNet = maybeMullvadDomain === 'mullvad.net';
 
+    const isExtensionRequest = details.documentUrl?.startsWith('moz-extension://');
+    const isConnCheck = isMullvadNet && details.url?.endsWith('am.i.mullvad.net/json');
+    const isDNSCheck = isMullvadNet && details.url?.endsWith('dnsleak.am.i.mullvad.net/');
     const isExtConnCheck = isExtensionRequest && (isConnCheck || isDNSCheck);
 
     if (isExtConnCheck) {