feat(core)!: Introduce insecure mode in task runner (#16911)

docker/images/n8n/n8n-task-runners.json

@@ -23,7 +23,6 @@
 				"N8N_RUNNERS_HEALTH_CHECK_SERVER_PORT",
 				"NODE_FUNCTION_ALLOW_BUILTIN",
 				"NODE_FUNCTION_ALLOW_EXTERNAL",
-				"N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION",
 				"NODE_OPTIONS",
 				"NODE_PATH",
 				"N8N_SENTRY_DSN",

packages/@n8n/config/src/configs/runners.config.ts

@@ -62,4 +62,11 @@ export class TaskRunnersConfig {
 	/** How often (in seconds) the runner must send a heartbeat to the broker, else the task will be aborted. (In internal mode, the runner will also  be restarted.) Must be greater than 0. */
 	@Env('N8N_RUNNERS_HEARTBEAT_INTERVAL')
 	heartbeatInterval: number = 30;
+
+	/**
+	 * Whether to disable all security measures in the task runner. **Discouraged for production use.**
+	 * Set to `true` for compatibility with modules that rely on insecure JS features.
+	 */
+	@Env('N8N_RUNNERS_INSECURE_MODE')
+	insecureMode: boolean = false;
 }

packages/@n8n/config/test/config.test.ts

@@ -255,6 +255,7 @@ describe('GlobalConfig', () => {
 			maxConcurrency: 10,
 			taskTimeout: 300,
 			heartbeatInterval: 30,
+			insecureMode: false,
 		},
 		sentry: {
 			backendDsn: '',

packages/@n8n/task-runner/src/config/js-runner-config.ts

@@ -8,13 +8,6 @@ export class JsRunnerConfig {
 	@Env('NODE_FUNCTION_ALLOW_EXTERNAL')
 	allowedExternalModules: string = '';
 
-	/**
-	 * Whether to allow prototype mutation for external libraries. Set to `true`
-	 * to allow modules that rely on runtime prototype mutation, e.g. `puppeteer`,
-	 * at the cost of security.
-	 *
-	 * @default false
-	 */
-	@Env('N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION')
-	allowPrototypeMutation: boolean = false;
+	@Env('N8N_RUNNERS_INSECURE_MODE')
+	insecureMode: boolean = false;
 }

packages/@n8n/task-runner/src/js-task-runner/__tests__/js-task-runner.test.ts

@@ -38,7 +38,7 @@ const defaultConfig = new MainConfig();
 defaultConfig.jsRunnerConfig ??= {
 	allowedBuiltInModules: '',
 	allowedExternalModules: '',
-	allowPrototypeMutation: true, // needed for jest
+	insecureMode: false,
 };
 
 describe('JsTaskRunner', () => {
@@ -1455,9 +1455,9 @@ describe('JsTaskRunner', () => {
 			expect(Duration.fromObject({ hours: 1 }).maliciousKey).toBeUndefined();
 		});
 
-		it('should allow prototype mutation when `allowPrototypeMutation` is true', async () => {
+		it('should allow prototype mutation when `insecureMode` is true', async () => {
 			const runner = createRunnerWithOpts({
-				allowPrototypeMutation: true,
+				insecureMode: true,
 			});
 
 			const outcome = await executeForAllItems({

packages/@n8n/task-runner/src/js-task-runner/js-task-runner.ts

@@ -30,15 +30,15 @@ import { type Context, createContext, runInContext } from 'node:vm';
 
 import type { MainConfig } from '@/config/main-config';
 import { UnsupportedFunctionError } from '@/js-task-runner/errors/unsupported-function.error';
-import { EXPOSED_RPC_METHODS, UNSUPPORTED_HELPER_FUNCTIONS } from '@/runner-types';
 import type {
 	DataRequestResponse,
 	InputDataChunkDefinition,
 	PartialAdditionalData,
 	TaskResultData,
 } from '@/runner-types';
-import type { TaskParams } from '@/task-runner';
+import { EXPOSED_RPC_METHODS, UNSUPPORTED_HELPER_FUNCTIONS } from '@/runner-types';
 import { noOp, TaskRunner } from '@/task-runner';
+import type { TaskParams } from '@/task-runner';
 
 import { BuiltInsParser } from './built-ins-parser/built-ins-parser';
 import { BuiltInsParserState } from './built-ins-parser/built-ins-parser-state';
@@ -95,6 +95,8 @@ export class JsTaskRunner extends TaskRunner {
 
 	private readonly taskDataReconstruct = new DataRequestResponseReconstruct();
 
+	private readonly mode: 'secure' | 'insecure' = 'secure';
+
 	constructor(config: MainConfig, name = 'JS Task Runner') {
 		super({
 			taskType: 'javascript',
@@ -117,19 +119,17 @@ export class JsTaskRunner extends TaskRunner {
 		const allowedExternalModules = parseModuleAllowList(
 			jsRunnerConfig.allowedExternalModules ?? '',
 		);
+		this.mode = jsRunnerConfig.insecureMode ? 'insecure' : 'secure';
 
 		this.requireResolver = createRequireResolver({
 			allowedBuiltInModules,
 			allowedExternalModules,
 		});
 
-		this.preventPrototypePollution(allowedExternalModules, jsRunnerConfig.allowPrototypeMutation);
+		if (this.mode === 'secure') this.preventPrototypePollution(allowedExternalModules);
 	}
 
-	private preventPrototypePollution(
-		allowedExternalModules: Set<string> | '*',
-		allowPrototypeMutation: boolean,
-	) {
+	private preventPrototypePollution(allowedExternalModules: Set<string> | '*') {
 		if (allowedExternalModules instanceof Set) {
 			// This is a workaround to enable the allowed external libraries to mutate
 			// prototypes directly. For example momentjs overrides .toString() directly
@@ -141,11 +141,11 @@ export class JsTaskRunner extends TaskRunner {
 			}
 		}
 
-		// Freeze globals if needed
-		if (!allowPrototypeMutation) {
+		// Freeze globals, except in tests because Jest needs to be able to mutate prototypes
+		if (process.env.NODE_ENV !== 'test') {
 			Object.getOwnPropertyNames(globalThis)
 				// @ts-expect-error globalThis does not have string in index signature
-				// eslint-disable-next-line @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-member-access
+				// eslint-disable-next-line @typescript-eslint/no-unsafe-return
 				.map((name) => globalThis[name])
 				.filter((value) => typeof value === 'function')
 				// eslint-disable-next-line @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-member-access
@@ -256,9 +256,15 @@ export class JsTaskRunner extends TaskRunner {
 
 				signal.addEventListener('abort', abortHandler, { once: true });
 
-				const taskResult = runInContext(this.createVmExecutableCode(settings.code), context, {
-					timeout: this.taskTimeout * 1000,
-				}) as Promise<TaskResultData['result']>;
+				let taskResult: Promise<TaskResultData['result']>;
+
+				if (this.mode === 'secure') {
+					taskResult = runInContext(this.createVmExecutableCode(settings.code), context, {
+						timeout: this.taskTimeout * 1000,
+					}) as Promise<TaskResultData['result']>;
+				} else {
+					taskResult = this.runDirectly<TaskResultData['result']>(settings.code, context);
+				}
 
 				void taskResult
 					.then(resolve)
@@ -319,9 +325,15 @@ export class JsTaskRunner extends TaskRunner {
 
 					signal.addEventListener('abort', abortHandler);
 
-					const taskResult = runInContext(this.createVmExecutableCode(settings.code), context, {
-						timeout: this.taskTimeout * 1000,
-					}) as Promise<INodeExecutionData>;
+					let taskResult: Promise<INodeExecutionData>;
+
+					if (this.mode === 'secure') {
+						taskResult = runInContext(this.createVmExecutableCode(settings.code), context, {
+							timeout: this.taskTimeout * 1000,
+						}) as Promise<INodeExecutionData>;
+					} else {
+						taskResult = this.runDirectly<INodeExecutionData>(settings.code, context);
+					}
 
 					void taskResult
 						.then(resolve)
@@ -551,4 +563,14 @@ export class JsTaskRunner extends TaskRunner {
 			`module.exports = async function VmCodeWrapper() {${code}\n}()`,
 		].join('; ');
 	}
+
+	private async runDirectly<T>(code: string, context: Context): Promise<T> {
+		// eslint-disable-next-line @typescript-eslint/no-implied-eval
+		const fn = new Function(
+			'context',
+			`with(context) { return (async function() {${code}\n})(); }`,
+		);
+		// eslint-disable-next-line @typescript-eslint/no-unsafe-call, @typescript-eslint/no-unsafe-return
+		return await fn(context);
+	}
 }

packages/cli/BREAKING-CHANGES.md

@@ -2,6 +2,20 @@
 
 This list shows all the versions which include breaking changes and how to upgrade.
 
+## 1.102.0
+
+### What changed?
+
+The `N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION` flag has been replaced with `N8N_RUNNERS_INSECURE_MODE`. The new flag
+disables all task runner security measures and is intended as an escape hatch for users who value compatibility
+with libraries like `puppeteer` at the cost of security.
+
+### When is action necessary?
+
+If you are using the `N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION` flag, or if you find that the task runner does not 
+currently support an external module that you rely on, then consider setting `N8N_RUNNERS_INSECURE_MODE=true`, 
+at your own risk.
+
 ## 1.98.0
 
 ### What changed?

packages/cli/src/commands/base-command.ts

@@ -138,7 +138,15 @@ export abstract class BaseCommand<F = never> {
 			await Container.get(CommunityPackagesService).init();
 		}
 
-		if (this.needsTaskRunner && this.globalConfig.taskRunners.enabled) {
+		const taskRunnersConfig = this.globalConfig.taskRunners;
+
+		if (this.needsTaskRunner && taskRunnersConfig.enabled) {
+			if (taskRunnersConfig.insecureMode) {
+				this.logger.warn(
+					'TASK RUNNER CONFIGURED TO START IN INSECURE MODE. This is discouraged for production use. Please consider using secure mode instead.',
+				);
+			}
+
 			const { TaskRunnerModule } = await import('@/task-runners/task-runner-module');
 			await Container.get(TaskRunnerModule).start();
 		}

packages/cli/src/task-runners/__tests__/task-runner-process.test.ts

@@ -26,6 +26,7 @@ describe('TaskRunnerProcess', () => {
 	const runnerConfig = mockInstance(TaskRunnersConfig);
 	runnerConfig.enabled = true;
 	runnerConfig.mode = 'internal';
+	runnerConfig.insecureMode = false;
 	const authService = mock<TaskBrokerAuthService>();
 	let taskRunnerProcess = new TaskRunnerProcess(logger, runnerConfig, authService, mock());
 
@@ -78,7 +79,7 @@ describe('TaskRunnerProcess', () => {
 			'DEPLOYMENT_NAME',
 			'NODE_PATH',
 			'GENERIC_TIMEZONE',
-			'N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION',
+			'N8N_RUNNERS_INSECURE_MODE',
 		])('should propagate %s from env as is', async (envVar) => {
 			jest.spyOn(authService, 'createGrantToken').mockResolvedValue('grantToken');
 			process.env[envVar] = 'custom value';
@@ -150,7 +151,7 @@ describe('TaskRunnerProcess', () => {
 			);
 		});
 
-		it('should use --disallow-code-generation-from-strings and --disable-proto=delete flags', async () => {
+		it('on secure mode, should use --disallow-code-generation-from-strings and --disable-proto=delete flags', async () => {
 			jest.spyOn(authService, 'createGrantToken').mockResolvedValue('grantToken');
 
 			await taskRunnerProcess.start();
@@ -161,5 +162,22 @@ describe('TaskRunnerProcess', () => {
 				expect.stringContaining('/packages/@n8n/task-runner/dist/start.js'),
 			]);
 		});
+
+		it('on insecure mode, should not use --disallow-code-generation-from-strings and --disable-proto=delete flags', async () => {
+			jest.spyOn(authService, 'createGrantToken').mockResolvedValue('grantToken');
+			runnerConfig.insecureMode = true;
+			const insecureTaskRunnerProcess = new TaskRunnerProcess(
+				logger,
+				runnerConfig,
+				authService,
+				mock(),
+			);
+
+			await insecureTaskRunnerProcess.start();
+
+			expect(spawnMock.mock.calls[0].at(1)).toEqual([
+				expect.stringContaining('/packages/@n8n/task-runner/dist/start.js'),
+			]);
+		});
 	});
 });

packages/cli/src/task-runners/task-runner-process.ts

@@ -59,7 +59,7 @@ export class TaskRunnerProcess extends TypedEmitter<TaskRunnerProcessEventMap> {
 		'NODE_FUNCTION_ALLOW_BUILTIN',
 		'NODE_FUNCTION_ALLOW_EXTERNAL',
 		'N8N_SENTRY_DSN',
-		'N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION',
+		'N8N_RUNNERS_INSECURE_MODE',
 		// Metadata about the environment
 		'N8N_VERSION',
 		'ENVIRONMENT',
@@ -67,6 +67,8 @@ export class TaskRunnerProcess extends TypedEmitter<TaskRunnerProcessEventMap> {
 		'NODE_PATH',
 	] as const;
 
+	private readonly mode: 'insecure' | 'secure' = 'secure';
+
 	constructor(
 		logger: Logger,
 		private readonly runnerConfig: TaskRunnersConfig,
@@ -80,6 +82,8 @@ export class TaskRunnerProcess extends TypedEmitter<TaskRunnerProcessEventMap> {
 			'Task Runner Process cannot be used in external mode',
 		);
 
+		this.mode = this.runnerConfig.insecureMode ? 'insecure' : 'secure';
+
 		this.logger = logger.scoped('task-runner');
 
 		this.runnerLifecycleEvents.on('runner:failed-heartbeat-check', () => {
@@ -109,13 +113,14 @@ export class TaskRunnerProcess extends TypedEmitter<TaskRunnerProcessEventMap> {
 	startNode(grantToken: string, taskBrokerUri: string) {
 		const startScript = require.resolve('@n8n/task-runner/start');
 
-		return spawn(
-			'node',
-			['--disallow-code-generation-from-strings', '--disable-proto=delete', startScript],
-			{
-				env: this.getProcessEnvVars(grantToken, taskBrokerUri),
-			},
-		);
+		const flags =
+			this.mode === 'secure'
+				? ['--disallow-code-generation-from-strings', '--disable-proto=delete']
+				: [];
+
+		return spawn('node', [...flags, startScript], {
+			env: this.getProcessEnvVars(grantToken, taskBrokerUri),
+		});
 	}
 
 	@OnShutdown()