dgram: reject null bytes in address before queueing

lib/dgram.js

@@ -61,6 +61,7 @@ const {
   validateAbortSignal,
   validateObject,
   validateString,
+  validateStringWithoutNullBytes,
   validateNumber,
   validatePort,
   validateUint32,
@@ -487,7 +488,7 @@ Socket.prototype.connect = function(port, address, callback) {
     address = '';
   }
 
-  validateString(address, 'address');
+  validateStringWithoutNullBytes(address, 'address');
 
   const state = this[kStateSymbol];
 
@@ -796,7 +797,7 @@ Socket.prototype.send = function(buffer,
     callback = address;
     address = undefined;
   } else if (address != null) {
-    validateString(address, 'address');
+    validateStringWithoutNullBytes(address, 'address');
   }
 
   healthCheck(this);

test/parallel/test-dgram-address-null-bytes.js

@@ -0,0 +1,49 @@
+'use strict';
+const common = require('../common');
+
+// An address with a null byte must be rejected synchronously by send() and
+// connect(), also on a socket that is not bound yet. Previously the operation
+// was queued until the implicit bind completed, and the lookup then threw from
+// inside the 'listening' event, where the caller could not catch it.
+
+const assert = require('assert');
+const dgram = require('dgram');
+
+const PORT = 12345;
+const address = '127.0.0.1\u0000.example.com';
+const expectedError = { code: 'ERR_INVALID_ARG_VALUE', name: 'TypeError' };
+
+{
+  const socket = dgram.createSocket('udp4');
+  socket.on('error', common.mustNotCall());
+
+  assert.throws(() => {
+    socket.send('hello', PORT, address, common.mustNotCall());
+  }, expectedError);
+
+  // The socket is still usable.
+  const receiver = dgram.createSocket('udp4');
+  receiver.on('message', common.mustCall((msg) => {
+    assert.strictEqual(msg.toString(), 'hello');
+    receiver.close();
+    socket.close();
+  }));
+  receiver.bind(0, '127.0.0.1', common.mustCall(() => {
+    socket.send('hello', receiver.address().port, '127.0.0.1',
+                common.mustSucceed());
+  }));
+}
+
+{
+  const socket = dgram.createSocket('udp4');
+  socket.on('error', common.mustNotCall());
+
+  assert.throws(() => {
+    socket.connect(PORT, address, common.mustNotCall());
+  }, expectedError);
+
+  // The failed connect() does not leave the socket in the connecting state.
+  socket.connect(PORT, '127.0.0.1', common.mustCall(() => {
+    socket.close();
+  }));
+}