Intuitive App for USB drive settings

I'm a total newbie to USB development and have a two-part Qn.
My goal is to create a GUI App for an USB drive to configure some of its settings like PINs to unlock the drive and 'allowed file-extensions', etc.

1. Do I need to write a desktop or web GUI App with mass-storage driver support to communicate with the device firmware to do this?

2. Or can I simply create a Portable App that runs on the device itself and talks directly to the device firmware? In this case, I don't need OS-driver support, right?