archipelagoandClaude Opus 5
2efab5f219
Unify rather than delete. The defect in F-03 was never "a second attempt to
create a key exists" — it was that failure was silent and the completion marker
lied about it. A second attempt is only dangerous when it is an unaudited second
PRODUCER carrying its own idea of success, its own absent retry policy and its
own absent failure record.
Single producer. gen_tls() is now the only code in the ISO build that creates
/etc/archipelago/ssl/archipelago.{key,crt}; gen_ssh() the only code that creates
/etc/ssh/ssh_host_*. Two secondary producers are gone:
- the Dockerfile's `openssl req` layer, which baked a keypair the strip layer
deleted moments later in the same build;
- the installer's "ensure SSL cert exists for nginx HTTPS" block, which before
the strip almost never fired and after it would have fired on every install.
Proof is mechanical, not a claim: every executable `openssl req` / `ssh-keygen
-A` invocation in the builder now lives inside the generator heredoc, and the
test suite fails if one appears outside it.
Build-time assertion. The one realistic total failure is a missing generator
binary, which is deterministic — no retry or reboot fixes it. A rootfs RUN layer
now fails the build if openssl or ssh-keygen is missing or non-executable.
openssl and openssh-server are both already in the package list (and
openssh-server hard-depends openssh-client, which ships ssh-keygen), so today
this is cheap insurance; it earns its place the first time someone edits that
list.
Self-heal, never dead-end. Fail-closed governs SERVING; retry governs
RECOVERING, and they are different things. Adds
archipelago-first-boot-secrets.timer (OnBootSec=5min, OnUnitActiveSec=15min),
installed and enabled with a hand-written symlink fallback because chroot
systemctl enable can fail silently. The service's own ConditionPathExists=!
makes every trigger a no-op once the marker exists, so a healthy node pays
nothing. On success the script now restarts consumers that are in `failed` —
try-reload-or-restart is a no-op on a failed unit, so without this a recovered
node would have valid keys on disk and nginx still down.
Never serve a bogus key. gen_tls parses both halves back with `openssl pkey`
and `openssl x509` before the swap, so a truncated or half-written artefact is
never what nginx reads.
Tests: 6 cases, each with an isolated negative control (transcripts in SUMMARY).
- case 4, TLS fails every attempt on a stripped root -> no key from any source.
Control: reintroduce a fallback key creation -> only case 4 red.
- case 5, self-heal: a failed run then a later successful run -> key present,
marker set, failed units restarted. Control: dead-end on a node that already
failed -> only case 5 red.
- case 6, single-producer invariant. Control: reintroduce the installer block
-> only case 6 red, naming the line.
Residual risk, stated plainly: a machine where generation can never succeed
still ends up with no SSH and no TLS. Build-time assertion removes the
deterministic cause, retry plus timer removes the transient ones, so what
remains is genuinely broken hardware — and it says so on the console and in
/var/lib/archipelago/first-boot-secrets.failed rather than quietly serving a
key nobody audited.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
9.1 KiB
KEY-02 — build-host evidence for the rootfs identity strip
Audit item: C-4 of docs/security/ENTROPY-SEED-AUDIT-2026-07-31.md (§868), which
belongs to finding F-03 (fail-open, never-retried first-boot secret regeneration over
a fleet-shared rootfs).
Status: ⛔ UNVERIFIED — awaiting a run on a real ISO build host.
The code change is committed and unit-tested; the tar listing that proves its effect on a real build has not been produced yet, because it requires a build host with podman/docker and enough disk for a full rootfs rebuild. Do not read anything below the "Result" heading as a passing check until it is filled in.
| Field | Value |
|---|---|
| Builder commit (Task 1) | 21043096 — fail-closed first-boot regeneration |
| Builder commit (Task 2) | 408b328c — rootfs identity strip |
| Builder commit (follow-up) | single-producer unification, build-time generator assertion, self-heal timer |
| Builder file | image-recipe/_archived/build-auto-installer-iso.sh (LIVE; image-recipe/build-debian-iso.sh execs it) |
| Build host | to be recorded |
| Date run | to be recorded |
| RECIPE_HASH observed | to be recorded — read it from the stamp file, see the caveat below |
The expectation is deliberately INVERTED relative to the audit
This is the single most important thing to understand when comparing this document with the audit, and the reason it is stated before the commands rather than after.
The audit's C-4 entry says:
Expected: SSH host keys and the TLS key present (they are baked — see
build-auto-installer-iso.sh:345,:463-469),random-seedabsent,machine-idabsent or zero-length. Anything else changes F-03's severity.
That expectation described the broken state the audit found, and recording it was how the audit measured the size of F-03. Phase 10 plan 10-03 Task 2 removed that material. So:
After this change, the audit's stated expectation is the FAILURE condition. If SSH host
keys or the TLS private key still appear in the tar, the strip layer did not run — most
likely because a cached archipelago-rootfs.tar was reused. That is not a regression in the
check; it is the check working.
The two negative findings the audit recorded are unchanged and must still hold:
var/lib/systemd/random-seed absent, etc/machine-id absent or zero-length.
Commands to run
Run all of these on the build host, from the repo root, on a checkout that contains
commits 21043096 and 408b328c.
1. Force a full rebuild
The strip layer lives inside the RECIPE_HASH region (between the # STEP 1: Build complete root filesystem and # STEP 2: Build minimal installer markers), so the hash changes and the
cached tar is invalidated automatically. --rebuild is passed anyway so that a stale tar
cannot mask the result for any reason:
UNBUNDLED=1 bash image-recipe/build-debian-iso.sh --rebuild
UNBUNDLED=1 is mandatory per CLAUDE.md and project memory — the default env silently
builds the wrong full-bundle variant.
2. List the identity artefacts in the shipped tar
WORK_DIR is image-recipe/build/auto-installer, so:
tar -tvf image-recipe/build/auto-installer/archipelago-rootfs.tar \
| grep -E 'etc/ssh/ssh_host|etc/machine-id|var/lib/systemd/random-seed|archipelago/ssl/archipelago'
3. Expected result after this plan
- no
etc/ssh/ssh_host_*entries at all - no
etc/archipelago/ssl/archipelago.keyand noarchipelago.crt(theetc/archipelago/ssl/directory must still be present — the first-boot staging swap needs somewhere to land) - no
var/lib/systemd/random-seed etc/machine-idpresent with size 0, or absent. Either satisfies "not shared"; record which one was actually observed rather than generalising.
Note on the TLS keypair specifically: it is now absent for two independent reasons, not one. The Dockerfile no longer generates it at all (that layer was removed so there is a single producer), and the strip layer still deletes it as belt-and-braces in case a future layer starts baking one. Seeing it present therefore means both defences were bypassed.
4. Confirm the provenance file rode along
tar -tvf image-recipe/build/auto-installer/archipelago-rootfs.tar | grep rootfs-identity-stripped
Expected: one entry, opt/archipelago/rootfs-identity-stripped. Its absence means the strip
layer did not execute and the whole check is void.
5. Confirm the regeneration path and its self-heal timer are still shipped
This is the brick check, and it is not optional. A stripped rootfs whose first-boot generation script failed to ship would leave every flashed node with no SSH host key and nothing to create one. The timer is part of the same check: without it, a node whose generators fail every in-boot retry has no unattended way back.
ls -l image-recipe/build/auto-installer/installer-iso/archipelago/scripts/first-boot-secrets.sh \
image-recipe/build/auto-installer/installer-iso/archipelago/scripts/archipelago-first-boot-secrets.service \
image-recipe/build/auto-installer/installer-iso/archipelago/scripts/archipelago-first-boot-secrets.timer
Expected: all three present, first-boot-secrets.sh executable.
5b. Confirm the build-time generator assertion actually ran
The rootfs build fails outright if openssl or ssh-keygen is missing or non-executable,
because that is the one way first-boot generation can fail deterministically — retries and
reboots would never fix it, so it must never reach a node. A successful build therefore
already proves the generators are present, and the build log says so:
grep 'first-boot secret generators present' <build log>
If you did not capture the log, assert it against the tar instead:
tar -tvf image-recipe/build/auto-installer/archipelago-rootfs.tar \
| grep -E 'usr/bin/(openssl|ssh-keygen)$'
Expected: both present and mode -rwxr-xr-x.
6. Record the RECIPE_HASH the builder actually used
cat image-recipe/build/auto-installer/archipelago-rootfs.recipe.sha256
Caveat — do not compute this hash from the repo file. image-recipe/build-debian-iso.sh
copies the archived builder to a temp path and rewrites its relative paths before exec'ing it,
and RECIPE_HASH hashes "$0" — the rewritten copy. The hashed region contains 35 such
rewritten path expressions, and SCRIPT_DIR is substituted with an absolute path, so the hash
is specific to the build host and checkout location. For reference, hashing the region of the
committed repo file directly gives d2dc4df5427fe73d48227aab08cdf6debfe8dd554e6b18e3718f8d37ea9d675c,
which is expected to differ from the stamp above.
Result
Paste the raw output of steps 2, 4, 5 and 6 here, then set the status at the top of this document to VERIFIED with the date and build-host label.
(pending — not yet run on a build host)
Verdict: pending
What this does and does not prove
Proves (once run): the rootfs tar extracted verbatim onto every disk flashed from the ISO carries no SSH host key, no TLS private key and no populated machine-id — so a first-boot regeneration failure degrades to "no key, the service refuses to start" rather than "fleet-shared key, silently", which is the substance of F-03.
Does not prove: that two nodes flashed from the same ISO actually end up with different keys. That is audit item C-3 (§779) and needs two physical machines; it remains separately UNVERIFIED. C-4 is a build-host check only.
Guidance for C-3: SSH and TLS are now equally sharp signals
An earlier revision of this document said SSH host keys were the sharper divergence signal for C-3, because the installer had a per-install TLS fallback that would produce a differing cert even if first-boot generation had failed. That asymmetry no longer exists.
There is now exactly one producer of each secret — gen_tls() and gen_ssh() inside
first-boot-secrets.sh — and no other code in the ISO build creates either. The Dockerfile no
longer bakes a TLS keypair and the installer's "ensure SSL cert exists" block is gone. So for
C-3, treat both the same way:
# on each node
ssh-keyscan -t ed25519 localhost 2>/dev/null | ssh-keygen -lf -
openssl x509 -in /etc/archipelago/ssl/archipelago.crt -noout -fingerprint -sha256
Pass: both fingerprints differ between the two nodes. Fail: either matches — a matching TLS fingerprint is now exactly as damning as a matching host key, whereas before it could have been explained away by the fallback.
Also check, on each node, that the run actually succeeded rather than merely being quiet:
ls -l /var/lib/archipelago/.secrets-regenerated # present on a healthy node
cat /var/lib/archipelago/first-boot-secrets.failed 2>&1 # absent on a healthy node
systemctl status archipelago-first-boot-secrets.timer # enabled; the self-heal path
The audit's original C-3 fail condition — a WARNING: line in the log alongside an existing
marker — can no longer occur by construction: the marker is only written when both generators
succeeded. If you ever see that combination, the fix has been reverted.