net: allow port 0 in connect()

The added validation allows non-negative numbers and numeric
strings. All other values result in a thrown exception.

Fixes: https://github.com/joyent/node/issues/9194
PR-URL: https://github.com/joyent/node/pull/9268
Reviewed-By: Julien Gilli <julien.gilli@joyent.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: James M Snell <jasnell@users.noreply.github.com>

lib/net.js

@@ -882,7 +882,7 @@ Socket.prototype.connect = function(options, cb) {
   } else {
     const dns = require('dns');
     var host = options.host || 'localhost';
-    var port = options.port | 0;
+    var port = 0;
     var localAddress = options.localAddress;
     var localPort = options.localPort;
     var dnsopts = {
@@ -896,8 +896,16 @@ Socket.prototype.connect = function(options, cb) {
     if (localPort && typeof localPort !== 'number')
       throw new TypeError('localPort should be a number: ' + localPort);
 
-    if (port <= 0 || port > 65535)
-      throw new RangeError('port should be > 0 and < 65536: ' + port);
+    if (typeof options.port === 'number')
+      port = options.port;
+    else if (typeof options.port === 'string')
+      port = options.port.trim() === '' ? -1 : +options.port;
+    else if (options.port !== undefined)
+      throw new TypeError('port should be a number or string: ' + options.port);
+
+    if (port < 0 || port > 65535 || isNaN(port))
+      throw new RangeError('port should be >= 0 and < 65536: ' +
+                           options.port);
 
     if (dnsopts.family !== 4 && dnsopts.family !== 6)
       dnsopts.hints = dns.ADDRCONFIG | dns.V4MAPPED;

src/tcp_wrap.cc

@@ -350,7 +350,7 @@ void TCPWrap::Connect(const FunctionCallbackInfo<Value>& args) {
 
   CHECK(args[0]->IsObject());
   CHECK(args[1]->IsString());
-  CHECK(args[2]->Uint32Value());
+  CHECK(args[2]->IsUint32());
 
   Local<Object> req_wrap_obj = args[0].As<Object>();
   node::Utf8Value ip_address(env->isolate(), args[1]);
@@ -381,7 +381,7 @@ void TCPWrap::Connect6(const FunctionCallbackInfo<Value>& args) {
 
   CHECK(args[0]->IsObject());
   CHECK(args[1]->IsString());
-  CHECK(args[2]->Uint32Value());
+  CHECK(args[2]->IsUint32());
 
   Local<Object> req_wrap_obj = args[0].As<Object>();
   node::Utf8Value ip_address(env->isolate(), args[1]);

test/parallel/test-net-create-connection.js

@@ -3,33 +3,99 @@ var assert = require('assert');
 var net = require('net');
 
 var tcpPort = common.PORT;
+var expectedConnections = 7;
 var clientConnected = 0;
 var serverConnected = 0;
 
 var server = net.createServer(function(socket) {
   socket.end();
-  if (++serverConnected === 4) {
+  if (++serverConnected === expectedConnections) {
     server.close();
   }
 });
+
 server.listen(tcpPort, 'localhost', function() {
   function cb() {
     ++clientConnected;
   }
 
+  function fail(opts, errtype, msg) {
+    assert.throws(function() {
+      var client = net.createConnection(opts, cb);
+    }, function (err) {
+      return err instanceof errtype && msg === err.message;
+    });
+  }
+
   net.createConnection(tcpPort).on('connect', cb);
   net.createConnection(tcpPort, 'localhost').on('connect', cb);
   net.createConnection(tcpPort, cb);
   net.createConnection(tcpPort, 'localhost', cb);
+  net.createConnection(tcpPort + '', 'localhost', cb);
+  net.createConnection({port: tcpPort + ''}).on('connect', cb);
+  net.createConnection({port: '0x' + tcpPort.toString(16)}, cb);
 
-  assert.throws(function () {
-    net.createConnection({
-      port: 'invalid!'
-    }, cb);
+  fail({
+    port: true
+  }, TypeError, 'port should be a number or string: true');
+
+  fail({
+    port: false
+  }, TypeError, 'port should be a number or string: false');
+
+  fail({
+    port: []
+  }, TypeError, 'port should be a number or string: ');
+
+  fail({
+    port: {}
+  }, TypeError, 'port should be a number or string: [object Object]');
+
+  fail({
+    port: null
+  }, TypeError, 'port should be a number or string: null');
+
+  fail({
+    port: ''
+  }, RangeError, 'port should be >= 0 and < 65536: ');
+
+  fail({
+    port: ' '
+  }, RangeError, 'port should be >= 0 and < 65536:  ');
+
+  fail({
+    port: '0x'
+  }, RangeError, 'port should be >= 0 and < 65536: 0x');
+
+  fail({
+    port: '-0x1'
+  }, RangeError, 'port should be >= 0 and < 65536: -0x1');
+
+  fail({
+    port: NaN
+  }, RangeError, 'port should be >= 0 and < 65536: NaN');
+
+  fail({
+    port: Infinity
+  }, RangeError, 'port should be >= 0 and < 65536: Infinity');
+
+  fail({
+    port: -1
+  }, RangeError, 'port should be >= 0 and < 65536: -1');
+
+  fail({
+    port: 65536
+  }, RangeError, 'port should be >= 0 and < 65536: 65536');
 });
+
+// Try connecting to random ports, but do so once the server is closed
+server.on('close', function() {
+  function nop() {}
+
+  net.createConnection({port: 0}).on('error', nop);
+  net.createConnection({port: undefined}).on('error', nop);
 });
 
 process.on('exit', function() {
-  assert.equal(clientConnected, 4);
+  assert.equal(clientConnected, expectedConnections);
 });
-

test/parallel/test-net-localerror.js

@@ -14,16 +14,6 @@ var net = require('net');
   localAddress: 'foobar',
 }, 'localAddress should be a valid IP: foobar');
 
-  connect({
-    host: 'localhost',
-    port: 65536
-  }, 'port should be > 0 and < 65536: 65536');
-
-  connect({
-    host: 'localhost',
-    port: 0
-  }, 'port should be > 0 and < 65536: 0');
-
 function connect(opts, msg) {
   assert.throws(function() {
     var client = net.connect(opts);