http: throw if 'host' agent header is not a string value

If the 'host' agent header is an array or other non-string value, throw.
PR-URL: #29568Fixes: #29408
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: gntem

lib/_http_agent.js

@@ -27,7 +27,11 @@ const net = require('net');
 constEventEmitter=require('events');
 constdebug=require('internal/util/debuglog').debuglog('http');
 const{ async_id_symbol }=require('internal/async_hooks').symbols;
-
+const{
+codes: {
+ERR_INVALID_ARG_TYPE,
+},
+}=require('internal/errors');
 // New Agent code.
 
 // The largest departure from the previous implementation is that
@@ -240,6 +244,11 @@ function calculateServerName(options, req) {
 letservername=options.host;
 consthostHeader=req.getHeader('host');
 if(hostHeader){
+if(typeofhostHeader!=='string'){
+thrownewERR_INVALID_ARG_TYPE('options.headers.host',
+'String',hostHeader);
+}
+
 // abc => abc
 // abc:123 => abc
 // [::1] => ::1

test/parallel/test-http-client-headers-host-array.js

@@ -0,0 +1,23 @@
+'use strict';
+
+require('../common');
+
+constassert=require('assert');
+consthttp=require('http');
+
+{
+
+constoptions={
+port: '80',
+path: '/',
+headers: {
+host: []
+}
+};
+
+assert.throws(()=>{
+http.request(options);
+},{
+code: /ERR_INVALID_ARG_TYPE/
+},'http request should throw when passing array as header host');
+}