worker: handle detached MessagePort from a different context

When `worker.moveMessagePortToContext` is used, the async handle
associated with the port, will be triggered more than needed (at least
one more time) and with null data. That can be avoided by simply
checking that the data is present and the port is not detached.

Fixes: #49075
Signed-off-by: Juan José Arboleda <[email protected]>

Author: juanarbol

src/node_messaging.cc

@@ -795,6 +795,11 @@ void MessagePort::OnMessage(MessageProcessingMode mode) {
 
   size_t processing_limit;
   if (mode == MessageProcessingMode::kNormalOperation) {
+    // Maybe the async handle was triggered empty or more than needed
+    // (called twiced on a new context).
+    if (GetTransferMode() == TransferMode::kDisallowCloneAndTransfer || !data_)
+      return;
+
     Mutex::ScopedLock(data_->mutex_);
     processing_limit = std::max(data_->incoming_messages_.size(),
                                 static_cast<size_t>(1000));

test/parallel/test-worker-workerdata-messageport.js

@@ -1,11 +1,11 @@
 'use strict';
 
 require('../common');
-const assert = require('assert');
+const assert = require('node:assert');
 
 const {
   Worker, MessageChannel
-} = require('worker_threads');
+} = require('node:worker_threads');
 
 const channel = new MessageChannel();
 const workerData = { mesage: channel.port1 };
@@ -59,3 +59,29 @@ const meowScript = () => 'meow';
              'listed in transferList'
   });
 }
+
+{
+  // Should not crash when MessagePort is transferred to another context.
+  // https://github.com/nodejs/node/issues/49075
+  const channel = new MessageChannel();
+  new Worker(`
+    const { runInContext, createContext } = require('node:vm')
+    const { workerData } = require('worker_threads');
+    const context = createContext(Object.create(null));
+    context.messagePort = workerData.messagePort;
+    runInContext(
+      \`messagePort.postMessage("Meow")\`,
+      context,
+      { displayErrors: true }
+    );
+    `, {
+    eval: true,
+    workerData: { messagePort: channel.port2 },
+    transferList: [channel.port2]
+  });
+  channel.port1.on(
+    'message',
+    (message) =>
+      assert.strictEqual(message, 'Meow')
+  );
+}