http: protect against response splitting attacks

This patch is a back-port of 3c293ba.
Closes #4696

lib/http.js

@@ -546,6 +546,11 @@ OutgoingMessage.prototype._storeHeader = function(firstLine, headers) {
   var self = this;
 
   function store(field, value) {
+    // Protect against response splitting. The if statement is there to
+    // minimize the performance impact in the common case.
+    if (/[\r\n]/.test(value))
+      value = value.replace(/[\r\n]+[ \t]*/g, '');
+
     messageHeader += field + ': ' + value + CRLF;
 
     if (connectionExpression.test(field)) {

test/simple/test-http-header-response-splitting.js

@@ -0,0 +1,64 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common'),
+    assert = require('assert'),
+    http = require('http');
+
+var testIndex = 0,
+    responses = 0;
+
+var server = http.createServer(function(req, res) {
+  switch (testIndex++) {
+    case 0:
+      res.writeHead(200, { test: 'foo \r\ninvalid: bar' });
+      break;
+    case 1:
+      res.writeHead(200, { test: 'foo \ninvalid: bar' });
+      break;
+    case 2:
+      res.writeHead(200, { test: 'foo \rinvalid: bar' });
+      break;
+    case 3:
+      res.writeHead(200, { test: 'foo \n\n\ninvalid: bar' });
+      break;
+    case 4:
+      res.writeHead(200, { test: 'foo \r\n \r\n \r\ninvalid: bar' });
+      server.close();
+      break;
+    default:
+      assert(false);
+  }
+  res.end('Hi mars!');
+});
+server.listen(common.PORT);
+
+for (var i = 0; i < 5; i++) {
+  var req = http.get({ port: common.PORT, path: '/' }, function(res) {
+    assert.strictEqual(res.headers.test, 'foo invalid: bar');
+    assert.strictEqual(res.headers.invalid, undefined);
+    responses++;
+  });
+}
+
+process.on('exit', function() {
+  assert.strictEqual(responses, 5);
+});