Cerisier: A Program Logic for Attestation

This repository contains the Rocq mechanization accompanying the submission "Cerisier: A Program Logic for Attestation". It provides a model of a capability machine with feature for local attestation and TEE, and principles to reason about the interaction of known, unknown, and attested code.

The repository depends on the submodule machine_utils. After cloning Cerisier, you can load the submodule using

git submodule update --init

Building the proofs

Installing the dependencies

You need to have opam >= 2.0 installed.

The development is known to compile with Coq 8.18.0, stdpp 1.9.0, and Iris 4.1.0. To install those, two options:

• Option 1: create a fresh local opam switch with everything needed:

opam switch create -y --repositories=default,coq-released=https://coq.inria.fr/opam/released . ocaml-base-compiler.4.14.0
eval $(opam env)

• Option 2 (manual installation): if you already have an opam switch with ocaml >= 4.14.0:

    # Add the coq-released repo (skip if you already have it)
    opam repo add coq-released https://coq.inria.fr/opam/released
    # Install Coq 8.18.0 (skip if already installed)
    opam update
    opam install coq.8.18.0
    opam install coq-iris.4.1.0

Troubleshooting

If the opam switch invocation fails at some point, either remove the _opam directory and re-run the command (this will redo everything), or do eval $(opam env) and then opam install -y . (this will continue from where it failed).

Building

make -jN  # replace N with the number of CPU cores of your machine

It is possible to run make fundamental to only build files up to the Fundamental Theorem.

Organization

section in the paper	Rocq files
Operational semantics (4)	opsem/*
Program Logic (5)	program_logic/*
Adequacy (6)	case_studies/template_adequacy_attestation.v
Logical Relation (7)	logrel/.v
FTLR (7.3)	logrel/ftlr/*, fundamental.v
Case Study - SOC (8.1)	case_studies/soc/*.v
Case Study - Mutual Attest (8.2)	case_studies/mutual_attestation/*.v
Case Study - Sensor Readout (8.3)	case_studies/memory_readout/*.v

Differences with the paper

Some definitions have different names from the paper.

name in paper => name in mechanization

In the operational semantics:

name in paper	name in mechanization
Running	Instr Executable
Halted	Instr Halted
Failed	Instr Failed

For technical reasons (so that Iris considers a single instruction as an atomic step), the execution mode is interweaved with the "Instr Next" mode, which reduces to a value. The Seq _ context can then return and continue to the next instruction. The full expression for an executing program is Seq (Instr Executable).

In the program logic:

name in paper	name in mechanization
EC(ecn)	EC⤇ ecn
tidx $\mapsto_{E}^{\square}$ I	enclave_all tidx I
tidx $\mapsto_{E}$ I	enclave_cur tidx I
DeInitialized(tidx)	enclave_prev tidx