From c42fc284f369b7d3343d1d92507ac27e3a90f85a Mon Sep 17 00:00:00 2001
From: Artur G Vieira <vieira.artur.g@gmail.com>
Date: Sat, 27 May 2017 03:00:09 +0000
Subject: [PATCH] http: edit _storeHeader to check for Trailer header

Test non-chunked message does not have trailer header set,
message will be terminated by the first empty line after the
header fields, regardless of the header fields present in the
message, and thus cannot contain a message body or 'trailers'.

Ref: nodejs#2842
---
 lib/_http_outgoing.js                         |  9 +++++
 lib/internal/errors.js                        |  2 ++
 .../test-http-server-de-chunked-trailer.js    | 33 +++++++++++++++++++
 3 files changed, 44 insertions(+)
 create mode 100644 test/parallel/test-http-server-de-chunked-trailer.js

diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index 9b492df85a83c0..87830b9e43dcea 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -33,6 +33,7 @@ const checkInvalidHeaderChar = common._checkInvalidHeaderChar;
 const outHeadersKey = require('internal/http').outHeadersKey;
 const async_id_symbol = process.binding('async_wrap').async_id_symbol;
 const nextTick = require('internal/process/next_tick').nextTick;
+const errors = require('internal/errors');
 
 const CRLF = common.CRLF;
 const debug = common.debug;
@@ -424,6 +425,14 @@ function _storeHeader(firstLine, headers) {
     }
   }
 
+  // Test non-chunked message does not have trailer header set,
+  // message will be terminated by the first empty line after the
+  // header fields, regardless of the header fields present in the
+  // message, and thus cannot contain a message body or 'trailers'.
+  if (this.chunkedEncoding !== true && state.trailer) {
+    throw new errors.Error('ERR_HTTP_TRAILER_INVALID');
+  }
+
   this._header = state.header + CRLF;
   this._headerSent = false;
 
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index eb4eecd29b6890..988be67675bf4d 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -113,6 +113,8 @@ E('ERR_IPC_SYNC_FORK', 'IPC cannot be used with synchronous forks');
 E('ERR_MISSING_ARGS', missingArgs);
 E('ERR_STDERR_CLOSE', 'process.stderr cannot be closed');
 E('ERR_STDOUT_CLOSE', 'process.stdout cannot be closed');
+E('ERR_HTTP_TRAILER_INVALID',
+  'Trailers are invalid with this transfer encoding');
 E('ERR_UNKNOWN_BUILTIN_MODULE', (id) => `No such built-in module: ${id}`);
 E('ERR_UNKNOWN_SIGNAL', (signal) => `Unknown signal: ${signal}`);
 E('ERR_UNKNOWN_STDIN_TYPE', 'Unknown stdin file type');
diff --git a/test/parallel/test-http-server-de-chunked-trailer.js b/test/parallel/test-http-server-de-chunked-trailer.js
new file mode 100644
index 00000000000000..d483297c5ab969
--- /dev/null
+++ b/test/parallel/test-http-server-de-chunked-trailer.js
@@ -0,0 +1,33 @@
+'use strict';
+const common = require('../common');
+
+// This test ensures that a Trailer header is set only when a chunked transfer
+// encoding is used.
+
+const assert = require('assert');
+const http = require('http');
+
+const server = http.createServer(common.mustCall(function(req, res) {
+  res.setHeader('Trailer', 'baz');
+  const trailerInvalidErr = {
+    code: 'ERR_HTTP_TRAILER_INVALID',
+    message: 'Trailers are invalid with this transfer encoding',
+    type: Error
+  };
+  assert.throws(() => res.writeHead(200, {'Content-Length': '2'}),
+                common.expectsError(trailerInvalidErr));
+  res.removeHeader('Trailer');
+  res.end('ok');
+}));
+server.listen(0, common.mustCall(() => {
+  http.get({ port: server.address().port }, common.mustCall((res) => {
+    assert.strictEqual(res.statusCode, 200);
+    let buf = '';
+    res.on('data', (chunk) => {
+      buf += chunk;
+    }).on('end', common.mustCall(() => {
+      assert.strictEqual(buf, 'ok');
+    }));
+    server.close();
+  }));
+}));