From 8c2cc63acb78f8a169c53804d64304e8e954f7df Mon Sep 17 00:00:00 2001
From: Dan Connolly <connolly@agoric.com>
Date: Tue, 9 Feb 2021 12:35:57 -0600
Subject: [PATCH] fix(xsnap): freeze API surface

---
 packages/xsnap/src/xsnap.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/xsnap/src/xsnap.js b/packages/xsnap/src/xsnap.js
index 646cb2d1912..e5ad4e1942d 100644
--- a/packages/xsnap/src/xsnap.js
+++ b/packages/xsnap/src/xsnap.js
@@ -32,6 +32,8 @@ const importMetaUrl = `file://${__filename}`;
 const encoder = new TextEncoder();
 const decoder = new TextDecoder();
 
+const { freeze } = Object;
+
 /**
  * @param {Uint8Array} arg
  * @returns {Uint8Array}
@@ -276,7 +278,7 @@ export function xsnap(options) {
     return vatExit.promise.catch(() => {});
   }
 
-  return {
+  return freeze({
     issueCommand,
     issueStringCommand,
     close,
@@ -285,5 +287,5 @@ export function xsnap(options) {
     execute,
     import: importModule,
     snapshot: writeSnapshot,
-  };
+  });
 }