Review 4727756972 (A2): the backout no longer trusts gpasswd — it re-reads
the live group database after removal; verified-absent gets the safe
message, anything else screams ROLLBACK INCOMPLETE, exits nonzero, and
names the exact remediation. The concurrent-login window (a session begun
between usermod and backout keeps the group) is CLOSED to the extent the
database can't reach: the backout detects live processes and names
loginctl terminate-user, and the success wording claims only what was
verified.
Review 4727641752 (A1): a failed grant for a user whose membership predates
the run (the hand-added-user scenario) now fails LOUDLY — they retain
socket access on part-converged policy, and the message says so with both
remediations (box revoke now, or fix and re-run). Their membership is not
stripped: breaking a working user over a failed re-grant is its own hazard.
The default-profile eth0 removal is deliberately not restored on failure —
that mutation only reduces capability, and restoring it would move the
failure state AWAY from fail-closed. Injected-failure coverage is criterion
(n), both flavors: fresh-user backout (fault at the LAST mutation, so the
rollback runs after every earlier one) with the group's absence verified
and a converging re-run; blocked narrowing staged for real with an
instance-local NIC parked on the private bridge.
Review A3, resolution 3 with the measurement demanded: criterion (m)
launches exactly 'incus launch --network boxnet' as the restricted user and
probes the raw NIC from inside — egress works, RFC1918 dropped (the ACL is
the network's), sibling probes dropped BOTH directions (the nft drop is the
host's), name enumeration blocked. The scoped guarantee is now stated in
box-design.md and measured on every run: box-minted instances carry per-NIC
port_isolation; raw attachments keep every network- and host-owned control,
losing only that redundant L2 layer. Instrument lesson kept as MU-5: the
probe's first cut minted the non-cloud image — no DHCP client, no lease,
and a dead NIC passes every negative probe vacuously; it now requires the
lease before believing its own answers.
Rehearsal: 54/54 (containers). test/cli.sh: 82 checks.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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