From 2e9ed4340092ab9a879d2e07b4ad8e52be31188f Mon Sep 17 00:00:00 2001
From: Joao Moreno <joao.moreno@microsoft.com>
Date: Tue, 8 Feb 2022 08:53:36 +0100
Subject: [PATCH] safeguard init exthost message

---
 .../workbench/api/worker/extensionHostWorker.ts | 17 +++++++++++++++--
 .../browser/webWorkerExtensionHost.ts           |  2 +-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/vs/workbench/api/worker/extensionHostWorker.ts b/src/vs/workbench/api/worker/extensionHostWorker.ts
index 676722cea9721..f439c2929ff5e 100644
--- a/src/vs/workbench/api/worker/extensionHostWorker.ts
+++ b/src/vs/workbench/api/worker/extensionHostWorker.ts
@@ -215,12 +215,25 @@ function connectToRenderer(protocol: IMessagePassingProtocol): Promise<IRenderer
 
 let onTerminate = (reason: string) => nativeClose();
 
+interface IInitMessage {
+	readonly type: 'vscode.init';
+	readonly data: ReadonlyMap<string, MessagePort>;
+}
+
+function isInitMessage(a: any): a is IInitMessage {
+	return !!a && typeof a === 'object' && a.type === 'vscode.init' && a.data instanceof Map;
+}
+
 export function create(): { onmessage: (message: any) => void } {
 	performance.mark(`code/extHost/willConnectToRenderer`);
 	const res = new ExtensionWorker();
 
 	return {
-		onmessage(messagePorts: ReadonlyMap<string, MessagePort>) {
+		onmessage(message: any) {
+			if (!isInitMessage(message)) {
+				return; // silently ignore foreign messages
+			}
+
 			connectToRenderer(res.protocol).then(data => {
 				performance.mark(`code/extHost/didWaitForInitData`);
 				const extHostMain = new ExtensionHostMain(
@@ -228,7 +241,7 @@ export function create(): { onmessage: (message: any) => void } {
 					data.initData,
 					hostUtil,
 					null,
-					messagePorts
+					message.data
 				);
 
 				onTerminate = (reason: string) => extHostMain.terminate(reason);
diff --git a/src/vs/workbench/services/extensions/browser/webWorkerExtensionHost.ts b/src/vs/workbench/services/extensions/browser/webWorkerExtensionHost.ts
index b33a75f0b0aaa..55ee8c884d5ec 100644
--- a/src/vs/workbench/services/extensions/browser/webWorkerExtensionHost.ts
+++ b/src/vs/workbench/services/extensions/browser/webWorkerExtensionHost.ts
@@ -188,7 +188,7 @@ export class WebWorkerExtensionHost extends Disposable implements IExtensionHost
 
 		// Send over message ports for extension API
 		const messagePorts = this._environmentService.options?.messagePorts ?? new Map();
-		iframe.contentWindow!.postMessage(messagePorts, '*', [...messagePorts.values()]);
+		iframe.contentWindow!.postMessage({ type: 'vscode.init', data: messagePorts }, '*', [...messagePorts.values()]);
 
 		port.onmessage = (event) => {
 			const { data } = event;