feat(ses): harden some Node.js intrinsics

packages/ses/src/lockdown.js

@@ -26,6 +26,7 @@ import {
   stringSplit,
   noEvalEvaluate,
   getOwnPropertyNames,
+  getPrototypeOf,
 } from './commons.js';
 import { makeHardener } from './make-hardener.js';
 import { makeIntrinsicsCollector } from './intrinsics.js';
@@ -281,6 +282,14 @@ export const repairIntrinsics = (options = {}) => {
 
   const intrinsics = finalIntrinsics();
 
+  const hostIntrinsics = { __proto__: null };
+
+  // The Node.js Buffer is a derived class of Uint8Array, and as such is often
+  // passed around where a Uint8Array is expected.
+  if (typeof globalThis.Buffer === 'function') {
+    hostIntrinsics.Buffer = globalThis.Buffer;
+  }
+
   /**
    * Wrap console unless suppressed.
    * At the moment, the console is considered a host power in the start
@@ -301,6 +310,19 @@ export const repairIntrinsics = (options = {}) => {
   );
   globalThis.console = /** @type {Console} */ (consoleRecord.console);
 
+  // The untamed Node.js console cannot itself be hardened as it has mutable
+  // internal properties, but some of these properties expose internal versions
+  // of classes from node's "primordials" concept.
+  // eslint-disable-next-line no-underscore-dangle
+  if (typeof (/** @type {any} */ (consoleRecord.console)._times) === 'object') {
+    // SafeMap is a derived Map class used internally by Node
+    // There doesn't seem to be a cleaner way to reach it.
+    hostIntrinsics.SafeMap = getPrototypeOf(
+      // eslint-disable-next-line no-underscore-dangle
+      /** @type {any} */ (consoleRecord.console)._times,
+    );
+  }
+
   // @ts-ignore assert is absent on globalThis type def.
   if (errorTaming === 'unsafe' && globalThis.assert === assert) {
     // If errorTaming is 'unsafe' we replace the global assert with
@@ -390,6 +412,7 @@ export const repairIntrinsics = (options = {}) => {
     // must be the operation that modifies the intrinsics.
     const toHarden = {
       intrinsics,
+      hostIntrinsics,
       globals: {
         // Harden evaluators
         Function: globalThis.Function,