worker: add feature access control API

Similarly to the previous commit, this API allows prohibiting usage of certain features inside a worker thread. Refs: https://github.com/nodejs/node/issues/22107
nodejs · addaleax · Aug 3, 2018 · Aug 3, 2018 · Aug 7, 2018 · Aug 19, 2018
commit b3cfaed28ca22962bf347312b681cec2bbbebe28
diff --git a/doc/api/worker_threads.md b/doc/api/worker_threads.md
@@ -305,13 +305,21 @@ if (isMainThread) {
 ```
 
 ### new Worker(filename[, options])
+<!-- YAML
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/???
+    description: The `accessControl` option was added.
+-->
 
 * `filename` {string} The path to the Worker’s main script. Must be
   either an absolute path or a relative path (i.e. relative to the
   current working directory) starting with `./` or `../`.
   If `options.eval` is true, this is a string containing JavaScript code rather
   than a path.
 * `options` {Object}
+  * `accessControl` {Object} A set of access restrictions that will be applied
+    to the worker thread. See [`process.accessControl.apply()`][] for details.
   * `eval` {boolean} If true, interpret the first argument to the constructor
     as a script that is executed once the worker is online.
   * `workerData` {any} Any JavaScript value that will be cloned and made
@@ -327,6 +335,10 @@ if (isMainThread) {
   * stderr {boolean} If this is set to `true`, then `worker.stderr` will
     not automatically be piped through to `process.stderr` in the parent.
 
+Note that if `accessControl.fsRead` is set to `false`, the worker thread will
+not be able to read its main script from the file system, so a source script
+should be passed in instead and the `eval` option should be set.
+
 ### Event: 'error'
 <!-- YAML
 added: v10.5.0
@@ -473,6 +485,7 @@ active handle in the event system. If the worker is already `unref()`ed calling
 [`port.on('message')`]: #worker_threads_event_message
 [`process.exit()`]: process.html#process_process_exit_code
 [`process.abort()`]: process.html#process_process_abort
+[`process.accessControl.apply()`]: process.html#process_process_accesscontrol_apply_restrictions
 [`process.chdir()`]: process.html#process_process_chdir_directory
 [`process.env`]: process.html#process_process_env
 [`process.stdin`]: process.html#process_process_stdin

diff --git a/lib/internal/worker.js b/lib/internal/worker.js
@@ -274,6 +274,12 @@ class Worker extends EventEmitter {
       publicPort: port2,
       hasStdin: !!options.stdin
     }, [port2]);
+
+    if (typeof options.accessControl === 'object' &&
+        options.accessControl !== null) {
+      this[kHandle].applyAccessControl(options.accessControl);
+    }
+
     // Actually start the new thread now that everything is in place.
     this[kHandle].startThread();
   }

diff --git a/src/node_worker.cc b/src/node_worker.cc
@@ -353,6 +353,22 @@ void Worker::New(const FunctionCallbackInfo<Value>& args) {
   new Worker(env, args.This());
 }
 
+void Worker::ApplyAccessControl(const FunctionCallbackInfo<Value>& args) {
+  Worker* w;
+  ASSIGN_OR_RETURN_UNWRAP(&w, args.This());
+  CHECK(w->stopped_);
+
+  AccessControl access_control;
+  Local<Object> obj;
+  if (!args[0]->ToObject(w->env()->context()).ToLocal(&obj) ||
+      !AccessControl::FromObject(w->env()->context(), obj)
+          .To(&access_control)) {
+    return;
+  }
+
+  w->env_->access_control()->apply(access_control);
+}
+
 void Worker::StartThread(const FunctionCallbackInfo<Value>& args) {
   Worker* w;
   ASSIGN_OR_RETURN_UNWRAP(&w, args.This());
@@ -434,6 +450,7 @@ void InitWorker(Local<Object> target,
     env->SetProtoMethod(w, "stopThread", Worker::StopThread);
     env->SetProtoMethod(w, "ref", Worker::Ref);
     env->SetProtoMethod(w, "unref", Worker::Unref);
+    env->SetProtoMethod(w, "applyAccessControl", Worker::ApplyAccessControl);
 
     Local<String> workerString =
         FIXED_ONE_BYTE_STRING(env->isolate(), "Worker");

diff --git a/src/node_worker.h b/src/node_worker.h
@@ -39,6 +39,8 @@ class Worker : public AsyncWrap {
   bool is_stopped() const;
 
   static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void ApplyAccessControl(
+      const v8::FunctionCallbackInfo<v8::Value>& args);
   static void StartThread(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void StopThread(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void GetMessagePort(const v8::FunctionCallbackInfo<v8::Value>& args);

diff --git a/test/parallel/test-worker-access-control.js b/test/parallel/test-worker-access-control.js
@@ -0,0 +1,57 @@
+// Flags: --experimental-worker
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const fs = require('fs');
+const child_process = require('child_process');
+const { Worker } = require('worker_threads');
+
+// Do not use isMainThread so that this test itself can be run inside a Worker.
+if (!process.env.HAS_STARTED_WORKER) {
+  process.env.HAS_STARTED_WORKER = 1;
+  const w = new Worker(__filename, {
+    accessControl: {
+      fsWrite: false,
+      childProcesses: false,
+      loadAddons: false,
+      createWorkers: false
+    }
+  });
+
+  w.on('exit', common.mustCall((code) => {
+    assert.strictEqual(code, 0);
+  }));
+} else {
+  // We needed fs read access to load modules before.
+  process.accessControl.apply({ fsRead: false });
+
+  common.expectsError(() => { fs.readFileSync(__filename); }, {
+    type: Error,
+    message: 'Access to this API has been restricted',
+    code: 'ERR_ACCESS_DENIED'
+  });
+
+  common.expectsError(() => { fs.writeFileSync(__filename, ''); }, {
+    type: Error,
+    message: 'Access to this API has been restricted',
+    code: 'ERR_ACCESS_DENIED'
+  });
+
+  common.expectsError(() => { child_process.spawnSync('node'); }, {
+    type: Error,
+    message: 'Access to this API has been restricted',
+    code: 'ERR_ACCESS_DENIED'
+  });
+
+  common.expectsError(() => { child_process.spawn('node'); }, {
+    type: Error,
+    message: 'Access to this API has been restricted',
+    code: 'ERR_ACCESS_DENIED'
+  });
+
+  common.expectsError(() => { new Worker(__filename); }, {
+    type: Error,
+    message: 'Access to this API has been restricted',
+    code: 'ERR_ACCESS_DENIED'
+  });
+}