allow buffers for crypto.randomBytes

node_crypto.diff

diff --git a/src/node_crypto.cc b/src/node_crypto.cc
index 8f2f750..8912eea 100644
--- a/src/node_crypto.cc
+++ b/src/node_crypto.cc
@@ -5503,14 +5503,21 @@ void RandomBytesCheck(RandomBytesRequest* req, Local<Value> argv[2]) {
       ERR_error_string_n(req->error(), errmsg, sizeof errmsg);
 
     argv[0] = Exception::Error(OneByteString(req->env()->isolate(), errmsg));
-    argv[1] = Null(req->env()->isolate());
     req->release();
   } else {
     char* data = nullptr;
     size_t size;
     req->return_memory(&data, &size);
     argv[0] = Null(req->env()->isolate());
-    argv[1] = Buffer::New(req->env(), data, size).ToLocalChecked();
+
+    if (!argv[1]->IsNull()) {
+      char* buf = reinterpret_cast<char*>(Buffer::Data(argv[1].As<Object>()));
+      for (size_t i = 0; i < size; i++) {
+        buf[i] = data[i];
+      }
+    } else {
+      argv[1] = Buffer::New(req->env(), data, size).ToLocalChecked();
+    }
   }
 }
 
@@ -5523,6 +5530,7 @@ void RandomBytesAfter(uv_work_t* work_req, int status) {
   HandleScope handle_scope(env->isolate());
   Context::Scope context_scope(env->context());
   Local<Value> argv[2];
+  argv[1] = Null(env->isolate());
   RandomBytesCheck(req, argv);
   req->MakeCallback(env->ondone_string(), arraysize(argv), argv);
   delete req;
@@ -5534,38 +5542,56 @@ void RandomBytes(const FunctionCallbackInfo<Value>& args) {
 
   // maybe allow a buffer to write to? cuts down on object creation
   // when generating random data in a loop
-  if (!args[0]->IsUint32()) {
-    return env->ThrowTypeError("size must be a number >= 0");
+  if (!args[0]->IsUint32() && !Buffer::HasInstance(args[0])) {
+    return env->ThrowTypeError("size must be a number >= 0 or a buffer");
   }
 
-  const int64_t size = args[0]->IntegerValue();
-  if (size < 0 || size > Buffer::kMaxLength)
-    return env->ThrowRangeError("size is not a valid Smi");
+  if (args[0]->IsUint32()) {
+    const int64_t size = args[0]->IntegerValue();
+    if (size < 0 || size > Buffer::kMaxLength)
+      return env->ThrowRangeError("size is not a valid Smi");
 
-  Local<Object> obj = env->NewInternalFieldObject();
-  RandomBytesRequest* req = new RandomBytesRequest(env, obj, size);
+    Local<Object> obj = env->NewInternalFieldObject();
+    RandomBytesRequest* req = new RandomBytesRequest(env, obj, size);
 
-  if (args[1]->IsFunction()) {
-    obj->Set(FIXED_ONE_BYTE_STRING(args.GetIsolate(), "ondone"), args[1]);
+    if (args[1]->IsFunction()) {
+      obj->Set(FIXED_ONE_BYTE_STRING(args.GetIsolate(), "ondone"), args[1]);
 
-    if (env->in_domain())
-      obj->Set(env->domain_string(), env->domain_array()->Get(0));
-    uv_queue_work(env->event_loop(),
-                  req->work_req(),
-                  RandomBytesWork,
-                  RandomBytesAfter);
-    args.GetReturnValue().Set(obj);
+      if (env->in_domain())
+        obj->Set(env->domain_string(), env->domain_array()->Get(0));
+      uv_queue_work(env->event_loop(),
+                    req->work_req(),
+                    RandomBytesWork,
+                    RandomBytesAfter);
+      args.GetReturnValue().Set(obj);
+    } else {
+      env->PrintSyncTrace();
+      Local<Value> argv[2];
+      argv[1] = Null(env->isolate());
+      RandomBytesWork(req->work_req());
+      RandomBytesCheck(req, argv);
+      delete req;
+
+      if (!argv[0]->IsNull())
+        env->isolate()->ThrowException(argv[0]);
+      else
+        args.GetReturnValue().Set(argv[1]);
+    }
   } else {
+    // Buffer
+    const int64_t size = Buffer::Length(args[0]);
+    Local<Object> obj = env->NewInternalFieldObject();
+    RandomBytesRequest* req = new RandomBytesRequest(env, obj, size);
     env->PrintSyncTrace();
+
     Local<Value> argv[2];
+    argv[1] = args[0];
     RandomBytesWork(req->work_req());
     RandomBytesCheck(req, argv);
     delete req;
 
     if (!argv[0]->IsNull())
       env->isolate()->ThrowException(argv[0]);
-    else
-      args.GetReturnValue().Set(argv[1]);
   }
 }