dummy

README

Dummy Device

The Dummy Device emulator is a simple device target for playing with the Firmware Transparency environment.

The device persistent state is stored in two files in a directory on disk:

• bundle.json - which contains the ProofBundle from the update
• firmware.bin - the firmware image from the update.

The Dummy Device has a simple "ROM" implementation which is intended to be thought of as a early stage reset/bootloader which validates the proof bundle and asserts that the firmware measurements match the manifest before chaining to the next stage bootloader if validation is successful.

For fun, the second-stage bootloader is implemented as a WASM VM (using the Life VM from the Perlin folks), and the firmware.bin is expected to be a compiled WASM binary. There is an example of such a binary contained in the .../testdata/firmware/dummy_device directory.

The WASM VM currently only provides a simple print(const char*) function (although this could be extended if required).

Documentation

Overview

dummy_emu is an "emulator" for the dummy device.

This emulator shows how the firmware transparency artifacts stored when firmware is updates are validated on boot to protect the device against tampering.

The device's initialisation routines in "ROM" are where this validation takes place, and the device only "jumps into" the firmware payload once successful validation has taken place.

Usage:

go run ./cmd/emulator/dummy --logtostderr --dummy_storage_dir=/tmp/dummy_device