archipelagoandClaude Opus 5
201ef474e7
Task 3 of 10-03 is a blocking checkpoint: proving the shipped rootfs tar is identity-free needs a real ISO build host with podman/docker and disk for a full rootfs rebuild. This commits the prepared evidence document with the exact command sequence, marked UNVERIFIED, rather than claiming the check passed. The document states the inverted expectation explicitly. The audit's C-4 entry expected SSH host keys and the TLS key to be PRESENT — that described the broken state it was measuring. After the strip layer those must be ABSENT, so the audit's stated expectation is now the failure condition. A future reader comparing the two would otherwise conclude the check regressed. Also records two things the operator would otherwise get wrong: - RECIPE_HASH must be read from the stamp file, not computed from the repo file. build-debian-iso.sh rewrites the builder's relative paths into a temp copy before exec, and the hash covers "$0"; the hashed region has 35 such rewritten expressions plus an absolutised SCRIPT_DIR, so the value is specific to the build host and checkout path. - C-4 is a build-host check only. Two-node key divergence is C-3 and stays separately UNVERIFIED; the note explains why SSH host keys are the sharper signal there than TLS, given the installer's per-install TLS fallback. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
6.6 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 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.
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 is still shipped
This is the brick check, and it is not optional. A stripped rootfs whose first-boot regeneration script failed to ship would leave every flashed node with no SSH host key and nothing to create one.
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
Expected: both present, first-boot-secrets.sh executable.
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.
Also worth recording when C-3 is run: the installer writes a per-install TLS keypair as a
fallback (build-auto-installer-iso.sh, the "Ensure SSL cert exists for nginx HTTPS" block).
That fallback fires on every install now that the rootfs ships without a keypair. It is
generated separately on each target machine, so it is per node and does not reopen F-03 — but
it does mean the two nodes' TLS certs will differ even if first-boot regeneration failed on
both. SSH host keys have no such fallback, so they are the sharper signal for C-3.