1 files changed, 84 insertions, 0 deletions
diff --git a/lib/internal/bootstrap/primordials.js b/lib/internal/bootstrap/primordials.js
new file mode 100644
index 0000000000..2a97e74542
--- /dev/null
+++ b/lib/internal/bootstrap/primordials.js
@@ -0,0 +1,84 @@
+'use strict';
+
+/* global breakAtBootstrap, primordials */
+
+// This file subclasses and stores the JS builtins that come from the VM
+// so that Node.js's builtin modules do not need to later look these up from
+// the global proxy, which can be mutated by users.
+
+// TODO(joyeecheung): we can restrict access to these globals in builtin
+// modules through the JS linter, for example: ban access such as `Object`
+// (which falls back to a lookup in the global proxy) in favor of
+// `primordials.Object` where `primordials` is a lexical variable passed
+// by the native module compiler.
+
+if (breakAtBootstrap) {
+  debugger;  // eslint-disable-line no-debugger
+}
+
+function copyProps(src, dest) {
+  for (const key of Reflect.ownKeys(src)) {
+    if (!Reflect.getOwnPropertyDescriptor(dest, key)) {
+      Reflect.defineProperty(
+        dest,
+        key,
+        Reflect.getOwnPropertyDescriptor(src, key));
+    }
+  }
+}
+
+function makeSafe(unsafe, safe) {
+  copyProps(unsafe.prototype, safe.prototype);
+  copyProps(unsafe, safe);
+  Object.setPrototypeOf(safe.prototype, null);
+  Object.freeze(safe.prototype);
+  Object.freeze(safe);
+  return safe;
+}
+
+// Subclass the constructors because we need to use their prototype
+// methods later.
+primordials.SafeMap = makeSafe(
+  Map,
+  class SafeMap extends Map {}
+);
+primordials.SafeWeakMap = makeSafe(
+  WeakMap,
+  class SafeWeakMap extends WeakMap {}
+);
+primordials.SafeSet = makeSafe(
+  Set,
+  class SafeSet extends Set {}
+);
+primordials.SafePromise = makeSafe(
+  Promise,
+  class SafePromise extends Promise {}
+);
+
+// Create copies of the namespace objects
+[
+  'JSON',
+  'Math',
+  'Reflect'
+].forEach((name) => {
+  const target = primordials[name] = Object.create(null);
+  copyProps(global[name], target);
+});
+
+// Create copies of intrinsic objects
+[
+  'Array',
+  'Date',
+  'Function',
+  'Object',
+  'RegExp',
+  'String'
+].forEach((name) => {
+  const target = primordials[name] = Object.create(null);
+  copyProps(global[name], target);
+  const proto = primordials[name + 'Prototype'] = Object.create(null);
+  copyProps(global[name].prototype, proto);
+});
+
+Object.setPrototypeOf(primordials, null);
+Object.freeze(primordials);