10-03 closed the build half of F-03: the ISO no longer bakes SSH host keys or
a TLS keypair into the shared rootfs, and first-boot regeneration fails closed.
Nodes already in the field receive none of that — the first-boot script is
installed by the installer, not shipped by OTA — so a node that hit the old
fail-open path is still running key material that every downloader of its ISO
also holds, and its completion marker guarantees it will never try again.
scripts/security/host-secrets-audit.sh decides, from the node's own disk alone,
which of those it is. Four signals in a fixed precedence: missing material can
never be shared material; the fail-open fingerprint (marker present plus the
literal `WARNING: TLS regeneration failed` / `WARNING: ssh-keygen -A failed`
lines the old script emitted) is direct evidence and outranks timestamps and
also names WHICH class survived; then key mtime against a first-boot anchor
(.secrets-regenerated, falling back to the installer's LUKS key then
machine-id). Verdicts are per-node / shared / fail-closed-missing / unknown,
and every one of them carries the evidence strings that produced it, each
naming the file it was read from.
per-node is never claimed from an absent signal. No anchor means `unknown`, and
a standing first-boot-secrets.failed record also means `unknown` — a clean
mtime is not evidence that generation succeeded. That is T-10-37: a false
per-node verdict leaves an exposed node looking clean, which is worse than no
verdict at all.
Rotation (D-06: detect-report-then-apply, recorded in
docs/security/KEY-02-FLEET-ROTATION.md):
- --detect is the default and is read-only; it always exits 0, because
detection is informational and must never fail a boot.
- --apply without --yes writes nothing at all, not even its own verdict file.
"Touches nothing" is worth being able to say without a footnote.
- --apply --yes refuses unless the verdict is `shared`, so the wrong node
cannot be rotated even deliberately.
- It stages the full replacement TLS pair AND host-key set before touching
anything live and aborts if either fails; records the OLD fingerprints
before the swap; does TLS first (a dead web UI is recoverable over SSH, the
converse is not); replaces host keys by mv-onto-the-existing-path rather
than rm-then-mv, so the directory is never momentarily empty; and RELOADS
sshd, never restarts it, so the operator's own session survives its own
rotation.
bootstrap.rs ships the boot unit through the existing run_runtime_assets
promotion and enables it --now, so the verdict lands with the OTA rather than
at the next reboot. handle_system_stats gains a host_secrets object read from
the on-disk verdict — cheap, never an error however malformed the file, and
deliberately carrying no fingerprints, because a payload polled every few
seconds does not need digests an operator on the node can already read.
tests/first-boot-secrets/rotation-tests.sh: 8 cases against temp roots through
the HOST_SECRETS_ROOT seam. Negative controls run and reverted, each reddening
exactly one case: dry run writing its verdict file (STATE-DIR-CHANGED); the
old fingerprints recorded after the swap instead of before (caught by an
ordering observation, not a content comparison — the systemctl stub records
whether the file existed at the moment of the first reload); a tolerated
generation failure leaving a half-rotated node; and `per-node` claimed with no
anchor.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
