buffer: fix copy() segfault with zero arguments

Buffer#copy() immediately does a ToObject() on the first argument before it checks if it's even an Object. This causes Object::HasIndexedPropertiesInExternalArrayData() to be run on nothing, triggering the segfault. Instead run HasInstance() on the args Value. Which will check if it's actually an Object, before checking if it contains data. Fixes: nodejs#1519 PR-URL: nodejs#1520 Reviewed-by: Evan Lucas <[email protected]>
Fishrock123 · Apr 29, 2015 · f049938 · f049938
1 parent f9b226c
commit f049938
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Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/src/node_buffer.cc b/src/node_buffer.cc
@@ -303,11 +303,11 @@ void Base64Slice(const FunctionCallbackInfo<Value>& args) {
 void Copy(const FunctionCallbackInfo<Value> &args) {
   Environment* env = Environment::GetCurrent(args);
 
-  Local<Object> target = args[0]->ToObject(env->isolate());
-
-  if (!HasInstance(target))
+  if (!HasInstance(args[0]))
     return env->ThrowTypeError("first arg should be a Buffer");
 
+  Local<Object> target = args[0]->ToObject(env->isolate());
+
   ARGS_THIS(args.This())
   size_t target_length = target->GetIndexedPropertiesExternalArrayDataLength();
   char* target_data = static_cast<char*>(

diff --git a/test/parallel/test-buffer.js b/test/parallel/test-buffer.js
@@ -1179,3 +1179,8 @@ var ps = Buffer.poolSize;
 Buffer.poolSize = 0;
 assert.equal(Buffer(1).parent, undefined);
 Buffer.poolSize = ps;
+
+// Test Buffer.copy() segfault
+assert.throws(function() {
+  Buffer(10).copy();
+});