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: #4837 PR-URL: #4839 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Roman Klauke <[email protected]> Reviewed-By: Brian White <[email protected]>

Author: evanlucas

lib/dns.js

@@ -189,6 +189,9 @@ exports.lookupService = function(host, port, callback){
 if(cares.isIP(host)===0)
 thrownewTypeError('host needs to be a valid IP address');
 
+if(typeofport!=='number')
+thrownewTypeError(`port argument must be a number, got "${port}"`);
+
 callback=makeAsync(callback);
 
 varreq=newGetNameInfoReqWrap();

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');
+},/invalidarguments/);
+
+assert.throws(function(){
+dns.lookupService('fasdfdsaf',0,noop);
+},/hostneedstobeavalidIPaddress/);
+
+assert.throws(function(){
+dns.lookupService('0.0.0.0','0',noop);
+},/portargumentmustbeanumber,got"0"/);
+
+assert.doesNotThrow(function(){
+dns.lookupService('0.0.0.0',0,noop);
+});