class decides root SSH's fate, and this is human's: install
/etc/ssh/sshd_config.d/00-rig-users.conf (PermitRootLogin no), where the NAME
is the mechanism — sshd_config is first-wins, the Include glob expands
lexically, and '-' sorts before '.', so it is read before bootstrap's
00-rig.conf and wins. Gated three ways, no --force: a marker must exist
(never shut the root door blind), it must say class=human (on a server root
is the control plane's automation identity — closing it severs fleet
management), and some rig-admin member must already hold a non-empty
authorized_keys (never close the only door). The gate's policy lives in the
lib as assert_marker_human so the harness proves every refusal against
fixture markers as non-root; RIG_ROLE_MARKER keeps the command pointable at
the same fixtures. Apply is bootstrap's validate-then-apply shape verbatim —
cmp-guard, sshd -t on the merged config before the restart with rollback,
then the sshd -T effective assertion. Bootstrap's own permitrootlogin
assertion widens to accept 'no': the closed door is strictly harder, never
broken, and by first-wins bootstrap cannot reopen it.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Operators become a declared fact, not an accumulation of adduser runs: a
line-based, bash-parseable users file (no YAML, no jq — a rig box has
neither) names each user, their roles, and their keys, and apply converges
the box to exactly that. Roles map to groups (admin→rig-admin with full
NOPASSWD sudo, rig→rig sudo for the rig binary only, box→incus with no
sudo — box's setup-host owns Incus, rig only asserts the group). Every
password stays locked always; the SSH key at the door is the
authentication. A user dropped from the file is found via the /etc/rig/users
ledger and locked, never deleted — deleting frees the uid and rots
attribution. The sudoers drop-in lands only after visudo -c passes, because
a bad file under sudoers.d takes down all of sudo. Class never gates apply
(#26: a shared root login is unattributable, so operators belong on every
class); the marker only colors what root SSH does next. The whole file is
validated in one pass before the root check, every error named with its
line, so refusals are provable in the non-root harness through the sourced
parser.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
