Towards a verified first-stage bootloader in Coq

Abstract

A cryptographic secure boot and attestation system usually depends on a measurement root -- a first-stage bootloader written to ROM that loads the boot payload into the machine's memory, cryptographically signs it and ensures that the boot payload begins execution from a clean-slate environment. We implement a first-stage bootloader heavily inspired by the Sanctum project [5], describe its specification in Coq relative to low-level RISC-V semantics, state the correctness of the implementation as a theorem in Coq and prove a few major lemmas necessary for establishing correctness.