From 34f49343ee83a1b4f21c133adfe28a4299b0a8da Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Fri, 9 Feb 2018 01:22:37 +0800
Subject: [PATCH] fs: fix stack overflow in fs.readdirSync

Previously, fs.readdirSync calls the function returned by
env->push_values_to_array_function() in batch and check the returned
Maybe right away in C++, which can lead to assertions if the call stack
already reaches the maximum size. This patch fixes that by returning
early the call fails so the stack overflow error will be properly
thrown into JS land.

PR-URL: https://github.com/nodejs/node/pull/18647
Fixes: https://github.com/nodejs/node/issues/18645
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 src/node_file.cc                               | 12 +++++++++---
 .../parallel/test-fs-readdir-stack-overflow.js | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 test/parallel/test-fs-readdir-stack-overflow.js

diff --git a/src/node_file.cc b/src/node_file.cc
index bef62ae766c7e0..9df13be5bd2dff 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -909,14 +909,20 @@ static void ReadDir(const FunctionCallbackInfo<Value>& args) {
       name_v[name_idx++] = filename.ToLocalChecked();
 
       if (name_idx >= arraysize(name_v)) {
-        fn->Call(env->context(), names, name_idx, name_v)
-            .ToLocalChecked();
+        MaybeLocal<Value> ret = fn->Call(env->context(), names, name_idx,
+                                         name_v);
+        if (ret.IsEmpty()) {
+          return;
+        }
         name_idx = 0;
       }
     }
 
     if (name_idx > 0) {
-      fn->Call(env->context(), names, name_idx, name_v).ToLocalChecked();
+      MaybeLocal<Value> ret = fn->Call(env->context(), names, name_idx, name_v);
+      if (ret.IsEmpty()) {
+        return;
+      }
     }
 
     args.GetReturnValue().Set(names);
diff --git a/test/parallel/test-fs-readdir-stack-overflow.js b/test/parallel/test-fs-readdir-stack-overflow.js
new file mode 100644
index 00000000000000..b7dea52cc37ec5
--- /dev/null
+++ b/test/parallel/test-fs-readdir-stack-overflow.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const common = require('../common');
+
+const fs = require('fs');
+
+function recurse() {
+  fs.readdirSync('.');
+  recurse();
+}
+
+common.expectsError(
+  () => recurse(),
+  {
+    type: RangeError,
+    message: 'Maximum call stack size exceeded'
+  }
+);