dgram: prefer strict equality, type validation

- Enforces strict comparisons in dgram - bindState should
always be strictly equal to one of the defined constant states,
and newHandle type is a string.

- Check that the argument `type` in createSocket is not null
when it is of type 'object', before using its `type` property.

- Adds a test to check dgram.createSocket is properly
validating its `type` argument.

PR-URL: https://github.com/nodejs/node/pull/8011
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>
Reviewed-By: Jackson Tian <shvyo1987@gmail.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/dgram.js b/lib/dgram.js
index 9037666d17..3a54c3c7f1 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -39,13 +39,13 @@ function lookup6(address, callback) {
 
 
 function newHandle(type) {
-  if (type == 'udp4') {
+  if (type === 'udp4') {
     const handle = new UDP();
     handle.lookup = lookup4;
     return handle;
   }
 
-  if (type == 'udp6') {
+  if (type === 'udp6') {
     const handle = new UDP();
     handle.lookup = lookup6;
     handle.bind = handle.bind6;
@@ -78,7 +78,7 @@ exports._createSocketHandle = function(address, port, addressType, fd, flags) {
 function Socket(type, listener) {
   EventEmitter.call(this);
 
-  if (typeof type === 'object') {
+  if (type !== null && typeof type === 'object') {
     var options = type;
     type = options.type;
   }
@@ -137,7 +137,7 @@ Socket.prototype.bind = function(port_ /*, address, callback*/) {
 
   self._healthCheck();
 
-  if (this._bindState != BIND_STATE_UNBOUND)
+  if (this._bindState !== BIND_STATE_UNBOUND)
     throw new Error('Socket is already bound');
 
   this._bindState = BIND_STATE_BINDING;
@@ -346,7 +346,7 @@ Socket.prototype.send = function(buffer,
 
   self._healthCheck();
 
-  if (self._bindState == BIND_STATE_UNBOUND)
+  if (self._bindState === BIND_STATE_UNBOUND)
     self.bind({port: 0, exclusive: true}, null);
 
   if (list.length === 0)
@@ -354,7 +354,7 @@ Socket.prototype.send = function(buffer,
 
   // If the socket hasn't been bound yet, push the outbound packet onto the
   // send queue and send after binding is complete.
-  if (self._bindState != BIND_STATE_BOUND) {
+  if (self._bindState !== BIND_STATE_BOUND) {
     enqueue(self, self.send.bind(self, list, port, address, callback));
     return;
   }