From 8f845ba28a07667b0f8bde452fc34829eae50f7d Mon Sep 17 00:00:00 2001
From: Fedor Indutny <fedor@indutny.com>
Date: Sat, 5 Dec 2015 16:03:30 -0500
Subject: [PATCH] stream_wrap: error if stream has StringDecoder

If `.setEncoding` was called on input stream - all emitted `data` will
be `String`s instances, not `Buffer`s. This is unacceptable for
`StreamWrap`, and should not lead to the crash.

Fix: https://github.com/nodejs/node/issues/3970
PR-URL: https://github.com/nodejs/node/pull/4031
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 lib/_stream_wrap.js                        | 16 ++++++++++++---
 test/parallel/test-stream-wrap-encoding.js | 23 ++++++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)
 create mode 100644 test/parallel/test-stream-wrap-encoding.js

diff --git a/lib/_stream_wrap.js b/lib/_stream_wrap.js
index 924d07a986a906..7eb3008484b2aa 100644
--- a/lib/_stream_wrap.js
+++ b/lib/_stream_wrap.js
@@ -4,6 +4,7 @@ const assert = require('assert');
 const util = require('util');
 const Socket = require('net').Socket;
 const JSStream = process.binding('js_stream').JSStream;
+const Buffer = require('buffer').Buffer;
 const uv = process.binding('uv');
 const debug = util.debuglog('stream_wrap');
 
@@ -39,15 +40,24 @@ function StreamWrap(stream) {
   };
 
   this.stream.pause();
-  this.stream.on('error', function(err) {
+  this.stream.on('error', function onerror(err) {
     self.emit('error', err);
   });
-  this.stream.on('data', function(chunk) {
+  this.stream.on('data', function ondata(chunk) {
+    if (!(chunk instanceof Buffer)) {
+      // Make sure that no further `data` events will happen
+      this.pause();
+      this.removeListener('data', ondata);
+
+      self.emit('error', new Error('Stream has StringDecoder'));
+      return;
+    }
+
     debug('data', chunk.length);
     if (self._handle)
       self._handle.readBuffer(chunk);
   });
-  this.stream.once('end', function() {
+  this.stream.once('end', function onend() {
     debug('end');
     if (self._handle)
       self._handle.emitEOF();
diff --git a/test/parallel/test-stream-wrap-encoding.js b/test/parallel/test-stream-wrap-encoding.js
new file mode 100644
index 00000000000000..d23faaab4a65f3
--- /dev/null
+++ b/test/parallel/test-stream-wrap-encoding.js
@@ -0,0 +1,23 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+
+const StreamWrap = require('_stream_wrap');
+const Duplex = require('stream').Duplex;
+
+const stream = new Duplex({
+  read: function() {
+  },
+  write: function() {
+  }
+});
+
+stream.setEncoding('ascii');
+
+const wrap = new StreamWrap(stream);
+
+wrap.on('error', common.mustCall(function(err) {
+  assert(/StringDecoder/.test(err.message));
+}));
+
+stream.push('ohai');