Files
SilverMetal/linux
SysAdmin f9e606d22d fix(linux/build): pin BUILDER_IMAGE to pushed registry digest (M1.1)
Image built from Dockerfile.builder@36f7672 was pushed to both
docker-registry:5000 (internal) and docker-registry.silverlabs.uk
(external) under tags m1.1-bootstrap + latest. Both URLs serve the
same registry, so the manifest digest is identical:

  sha256:cedef039425e0b0f5901c1023eda820c7aa38ab4b81c2bb1e12d64cadb3d6c85

Default points at the internal hostname for CI; external dev overrides
via BUILDER_IMAGE env var.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-26 11:48:48 +01:00
..

SilverMetal OS — Linux

Status: Phase 1 (planning) → moving to milestone 1.1 (reproducible Kicksecure fork build)

🔒 SilverMetal OS product line — we ship the operating system.

The reference SilverMetal flavour. Tier A — full kernel-level hardening, verified boot we control, Debian/Kicksecure-based.

Scope (v1)

See ../docs/roadmap.md Phase 1.

Hardening must-haves

  • Kicksecure base (Debian-derived, hardened upstream)
  • linux-hardened kernel + KSPP sysctl/build flags
  • Secure Boot with our shim/MOK
  • TPM2 PCR-bound LUKS2 unlock (Argon2id), full-disk encryption mandatory
  • AppArmor strict profiles for browsers, mail, viewers, networked daemons
  • GrapheneOS hardened_malloc as system allocator
  • bubblewrap + Flatpak primary; firejail for legacy .deb
  • nftables default-deny inbound, encrypted DNS, SilverVPN always-on default
  • Zero upstream telemetry — verified by integration test
  • SilverBrowser default (ungoogled-chromium-rebranded v1)
  • SilverVPN integrated from existing SilverLABS/SilverVPN (Linux client + tunnel service)
  • SilverSync v1 (Nextcloud-backed, client-side encryption)
  • A/B updates with rollback, signed by our keys
  • Optional amnesic session mode

Out of scope (v1)

  • Atomic / immutable root (v1.1 — ostree experiment)
  • dm-verity on / (v1.1)
  • ARM64 / Apple Silicon (v2)
  • Tor-by-default variant (sibling product later)

Directory layout

linux/
├── build/             # live-build pipeline, reproducible-build config
├── kernel/            # config fragments, linux-hardened pinning
├── overlay/           # /etc + /usr/share/silvermetal + skel hardening overlay
├── packages/
│   ├── include.list   # what's installed
│   └── exclude.list   # what's purged (snap, telemetry, etc.)
├── apparmor/          # custom strict profiles
├── nftables/          # default ruleset
├── installer/         # Calamares branding + hardened defaults
├── update-server/     # signing + repo hosting (infra-as-code)
└── tests/
    ├── lynis-baseline/
    ├── kspp-check/
    └── telemetry-leak/

Verification gates (must pass before public alpha)

  • Two clean builds from same commit → identical SHA256
  • kconfig-hardened-check passes
  • Lynis hardening score ≥ 90
  • 30-min idle telemetry capture: zero packets to MS/Google/Apple/Mozilla/Canonical/Debian/analytics
  • TPM tamper test: LUKS correctly falls back to passphrase
  • AppArmor: every networked binary confined or documented
  • Independent privacy-engineering review

Upstream we depend on

  • Kicksecure — fork base
  • linux-hardened — kernel patchset
  • GrapheneOS hardened_malloc — allocator
  • KSPP — kernel config authority
  • secureblue — reference for v1.1 immutable design
  • SilverLABS/SilverVPN — VPN client + tunnel service (existing, integrated)