From c5c9515c1b8abea2fd98cdd1319176ea1c367764 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 7991cdd3504..9f9c7044f91 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -1132,14 +1132,20 @@ 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 00000000000..b7dea52cc37
--- /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'
+  }
+);