ImgRep

Repository of reproducibly built images of common open source Linux toolchains and software with reputation anchored signatures.

About

We have learned a lot of lessons about supply chain integrity over the years, and the greatest of them may be that any system that is complex to review and assigns trust of significant components to single human points of failure, is doomed to have failure.

Most linux distributions rely on complex package management systems for which only a single implementation exists. They assign package signing privileges to individual maintainers at best. Modern popular distros often fail to even do this, having a central machine somewhere blindly signing all unsigned contributions from the public.

We will cover an exhaustive comparison of the supply chain strategies of other linux distros elsewhere, but suffice to say while many are pursuing reproducible builds, minimalism, or signing... any one distro delivering on all of these does not seem in the cards any time soon.

This is generally a human problem. Most distros end up generating a lot of custom tooling for package management, which in turn rapidly grows in complexity to meet demands ranging from hobby desktop systems production servers.

This complexity demands a lot of cycles to maintain, and this means in practice lowering the barrier to entry to allow any hobbyist to contribute and maintain packages with minimal friction and rarely a requirement of signing keys or mandatory reproducible builds, let alone multiple signed reproduction proofs.

Suffice to say, we feel every current Linux distribution has single points of human failure, or review complexity, that makes it undesirable for threat models that assume any single human can be hacked or coerced.

Building

Requirements

• An OCI building runtime
  • Currently Docker supported, but will support buildah and podman
• Gnu Make

Compile all packages

make

Compile specific package

make out/rust.tgz

Reproduce all changed packages

make reproduce

Reproduce all packages without cache

make clean reproduce

Sign current manifest of package hashes

make sign

Goals

Not all of these goals are realized yet, but should at least help you decide if this project is something you want to contribute to or keep an eye on for the future.

Integrity

• Anyone can reproduce the entire tree with tools from their current distro
• Hosted CI servers auto-sign confirmed deterministic builds
  • Like NixOS
• Maintainers sign all package additions/changes
  • Like Gentoo, Debian, Fedora, Guix
• Reviewers locally build and counter-sign all new binary packages
  • No one does this, as far as we can tell.

Reproducibility

• Trust no single external source of binaries
  • Bootstrap from two different third party signed distros
• Never use external binaries
  • Bootstrap from 0, always, even if it means going back in time
    • Go, rust require extensive work to bootstrap all the way back to gcc
    • Guix is the only distro that does this for rust to our knowledge
• Full-Source Bootstrap from x86_64 assembly
  • Take maximum advantage of the hard won wins by the Guix team
  • Bootstrap from guile driver reproduced on multiple signed distros

Minimalism

• Based on musl libc
  • Basis of successful minimal distros like Alpine, Adelie, Talos, Void
  • Implemented with about 1/4 the code of glibc
  • Required to produce portable static binaries in some languages
  • Less prone to buffer overflows
  • Puts being light, fast, and correct before compatibility
• Package using tools you already have
  • OCI build tool of choice (Docker, Buildah, Podman)
  • Make (for dependency management)
  • Prove hashes of bootstrap layer builds match before proceeding
• Keep package definitions lean and readable with simple CLI and no magic