Supplementary groups are read at LOGIN, so 'gpasswd -d' does nothing to a
session the user already holds — and after --purge, a stale-group process
could touch incus-user and lazily RECREATE the project with stock defaults:
the unhardened NAT bridge, un-narrowed, strictly worse than the granted
state. Adversarial review caught it; verified live, then closed:
- revoke --purge terminates the user's sessions first (loginctl, then
pkill), and refuses to purge under processes it cannot kill
- bare revoke says out loud that held sessions keep the socket until they
end, and names the loginctl command — instead of claiming a lockout it
did not deliver (help/README/design doc reworded to match)
- a failed grant backs out its own group-add on exit (trap, disarmed on
success): no half-granted user holding an un-narrowed socket while the
admin reads the error. Verified by injecting a bad profile YAML
- the rehearsal now holds a session open across the purge and demands it
dies with the tier (criterion l, 42nd check)
Smaller review findings, same pass: the escape-hatch probes assert the
refusal's REASON instead of any nonzero exit (an image hiccup must not read
as 'the escape is closed'); probe_from maps an outer-timeout kill to
dropped, not reachable; the rehearsal cleanup keeps the account when a purge
fails so doctor can name the leftovers; the purge asserts the trust
certificate's absence; cmd_new distinguishes a dead daemon from a missing
stack before prescribing setup-host; grant's success message names the
user-<uid> bridge variant correctly on big-uid hosts.
Rehearsal after: 42/42 (containers). test/cli.sh: 76 checks.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
drill/multiuser.sh: two throwaway users, real grants, real boxes, and the
contract measured from INSIDE them — #74's criteria (a)-(f) plus what the
findings added: the cross-user sibling drop, the closed private-bridge
escape hatches, incus-user re-sync survival, scoped revoke --purge. Its own
first runs are in RUNS.md (MU-1..3): both false FAILs were the instrument,
and both lessons (keep the mint's narration; probe a SIBLING's name, never
your own — /etc/hosts answers for you) are now comments in the script.
test/cli.sh: box_tier() driven against a shim id for all five cases
(including both-groups → admin: membership wins at the socket), the two
copies diffed byte-identical, the tier scripts' usage contracts driven for
real, and grep-guards on every load-bearing line a daemon-free run cannot
exercise — the expose guard's position, the boxnet-and-only-boxnet
narrowing, the snapshot allow, 'incus:snapshot restore'.
ci.yml: a second job stands up the real stack on the runner (setup-host,
doctor, then the rehearsal in container mode) — every PR now proves the
tier's semantics against a live daemon. The tier's mechanics are
instance-type-independent (the drop, the ACL, dns.mode and port_isolation
bind to boxnet, not the instance); the VM trust boundary itself stays a
real-hardware ritual, like the full drill.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
