From d4f0f3fa0dfe853b1b90efad114c9448913e235b Mon Sep 17 00:00:00 2001
From: Evan Lucas <evanlucas@me.com>
Date: Sun, 24 Jan 2016 08:58:56 -0600
Subject: [PATCH] dns: throw a TypeError in lookupService with invalid port

Previously, port was assumed to be a number and would cause an abort in
cares_wrap. This change throws a TypeError if port is not a number
before we actually hit C++.

Fixes: https://github.com/nodejs/node/issues/4837
PR-URL: https://github.com/nodejs/node/pull/4839
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Roman Klauke <romaaan.git@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
---
 lib/dns.js                |  3 +++
 test/parallel/test-dns.js | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/dns.js b/lib/dns.js
index 782cdfa3f7..6683eacf14 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -189,6 +189,9 @@ exports.lookupService = function(host, port, callback) {
   if (cares.isIP(host) === 0)
     throw new TypeError('host needs to be a valid IP address');
 
+  if (typeof port !== 'number')
+    throw new TypeError(`port argument must be a number, got "${port}"`);
+
   callback = makeAsync(callback);
 
   var req = new GetNameInfoReqWrap();
diff --git a/test/parallel/test-dns.js b/test/parallel/test-dns.js
index 3362e8c534..04264907d3 100644
--- a/test/parallel/test-dns.js
+++ b/test/parallel/test-dns.js
@@ -145,3 +145,19 @@ assert.doesNotThrow(function() {
     hints: dns.ADDRCONFIG | dns.V4MAPPED
   }, noop);
 });
+
+assert.throws(function() {
+  dns.lookupService('0.0.0.0');
+}, /invalid arguments/);
+
+assert.throws(function() {
+  dns.lookupService('fasdfdsaf', 0, noop);
+}, /host needs to be a valid IP address/);
+
+assert.throws(function() {
+  dns.lookupService('0.0.0.0', '0', noop);
+}, /port argument must be a number, got "0"/);
+
+assert.doesNotThrow(function() {
+  dns.lookupService('0.0.0.0', 0, noop);
+});