From fdb2408db602aaf21dd036688c5e6c1e49ad184b Mon Sep 17 00:00:00 2001
From: Robert Chiras <robert.chiras@intel.com>
Date: Thu, 19 May 2016 17:13:20 +0300
Subject: [PATCH] child_process: Check stderr before accessing it
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If something bad happens in spawnSync, stderr might be null. Therefore,
we have to check it before using it, so we won't mask the actual
exception.

PR-URL: https://github.com/nodejs/node/pull/6877
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Robert Jefe Lindstädt <robert.lindstaedt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
---
 lib/child_process.js                           |  4 ++--
 test/sequential/test-child-process-execsync.js | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/child_process.js b/lib/child_process.js
index 02d7c2344798f0..727ac230ab18d8 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -479,7 +479,7 @@ function execFileSync(/*command, args, options*/) {
 
   var ret = spawnSync(opts.file, opts.args.slice(1), opts.options);
 
-  if (inheritStderr)
+  if (inheritStderr && ret.stderr)
     process.stderr.write(ret.stderr);
 
   var err = checkExecSyncError(ret);
@@ -499,7 +499,7 @@ function execSync(/*command, options*/) {
   var ret = spawnSync(opts.file, opts.args, opts.options);
   ret.cmd = opts.cmd;
 
-  if (inheritStderr)
+  if (inheritStderr && ret.stderr)
     process.stderr.write(ret.stderr);
 
   var err = checkExecSyncError(ret);
diff --git a/test/sequential/test-child-process-execsync.js b/test/sequential/test-child-process-execsync.js
index 359799dd459e98..76da39c0e6b12d 100644
--- a/test/sequential/test-child-process-execsync.js
+++ b/test/sequential/test-child-process-execsync.js
@@ -12,6 +12,18 @@ var start = Date.now();
 var err;
 var caught = false;
 
+// Verify that stderr is not accessed when a bad shell is used
+assert.throws(
+  function() { execSync('exit -1', {shell: 'bad_shell'}); },
+  /ENOENT/,
+  'execSync did not throw the expected exception!'
+);
+assert.throws(
+  function() { execFileSync('exit -1', {shell: 'bad_shell'}); },
+  /ENOENT/,
+  'execFileSync did not throw the expected exception!'
+);
+
 try {
   var cmd = `"${process.execPath}" -e "setTimeout(function(){}, ${SLEEP});"`;
   var ret = execSync(cmd, {timeout: TIMER});