Merge pull request #445 from XmiliaH/fix-444

Security fix for issue 444.

Author: XmiliaH

lib/setup-sandbox.js

@@ -51,7 +51,10 @@ const {
 	AsyncGeneratorFunction
 } = data;
 
-const localWeakMapGet = LocalWeakMap.prototype.get;
+const {
+	get: localWeakMapGet,
+	set: localWeakMapSet
+} = LocalWeakMap.prototype;
 
 function localUnexpected() {
 	return new VMError('Should not happen');
@@ -282,8 +285,8 @@ if (typeof OriginalCallSite === 'function') {
 				}
 				return value(error, sst);
 			};
-			wrappedPrepareStackTrace.set(value, newWrapped);
-			wrappedPrepareStackTrace.set(newWrapped, newWrapped);
+			localReflectApply(localWeakMapSet, wrappedPrepareStackTrace, [value, newWrapped]);
+			localReflectApply(localWeakMapSet, wrappedPrepareStackTrace, [newWrapped, newWrapped]);
 			currentPrepareStackTrace = newWrapped;
 		}
 	})) throw localUnexpected();

test/vm.js

@@ -1058,6 +1058,18 @@ describe('VM', () => {
 		const sst = vm2.run('Error.prepareStackTrace = (e,sst)=>sst;const sst = new Error().stack;Error.prepareStackTrace = undefined;sst');
 		assert.strictEqual(vm2.run('sst=>Object.getPrototypeOf(sst)')(sst), vm2.run('Array.prototype'));
 		assert.throws(()=>vm2.run('sst=>sst[0].getThis().constructor.constructor')(sst), /TypeError: Cannot read propert.*constructor/);
+		assert.throws(()=>vm2.run(`
+			const { set } = WeakMap.prototype;
+			WeakMap.prototype.set = function(v) {
+				return set.call(this, v, v);
+			};
+			Error.prepareStackTrace =
+			Error.prepareStackTrace =
+			(_, c) => c.map(c => c.getThis()).find(a => a);
+			const { stack } = new Error();
+			Error.prepareStackTrace = undefined;
+			stack.process
+		`));
 	});
 
 	it('Node internal prepareStackTrace attack', () => {