The four-way client-cert split gives each store reader its own leaf, and
three of the four readers render only where their own leaf exists. On a
host that mints its own PKI glue-bao-tls.nix defaults all eight, so there
is nothing to do; on a hand-configured remote-store hive, omitting one
pair used to mean that unit silently did not render — a privilege-
narrowing unit absent from a green build, with the missing unit as the
only evidence.
Each of the three now asserts its own pair, shaped after
swarm-grafana.nix's haveClientIdentity assertion and named to the pair it
needs. What differs from Grafana's is the gate: these fire only where the
host demonstrably reads the store (it holds deploy.bao.clientCertFile and
clientKeyFile) and the consumer is on. A host with no store identity is
the supported no-store deployment and still evaluates; the collector's
no-secret degrade is untouched, because that host holds no clientCertFile
either.
Also rewords three passive-voice sentences in docs/swarm/secrets.md that
vale flagged, and documents what the refusal costs and where it stays
silent.
Four units read one path each out of the store, and all four logged in
holding `deploy.bao.clientCertFile` — the hive's own leaf. Bao identifies
a principal by the subject of the certificate it presents, so four
readers behind one certificate were ONE principal, and the only grant
expressible was the union of what the four need: read on
`swarm/agents/*`, `swarm/hives/<hive>/*` and `swarm/services/*`. The unit
fetching Grafana's OIDC client secret could fetch every agent credential
in the swarm; the one fetching this hive's matrix token could fetch
Grafana's. Least privilege was not misconfigured here, it was
unrepresentable.
Each now holds a leaf, a cert-auth role and a policy of its own, and each
policy is the single `secret/data/…` path that unit's own script names —
spelled to the leaf, not to a prefix, the way matrix-ctl's already is.
Following the four exemplars in-tree rather than building a mechanism:
`signLeaf` mints the leaves, `swarm-bao.nix` writes the roles from the
bootstrap token, the consumers name their own pair.
Two of the four are written PER HIVE and two are not, which is the shape
of the paths rather than a preference. A matrix appservice token and a
queue credential live under `swarm/hives/<name>/` and every hive runs a
reader for its own, so one role for all of them would have to be granted
`hives/*` — letting one hive read another's, a reach no hive has today.
An OIDC client secret lives under `swarm/services/<client-id>/` and a
swarm registers each exactly once, so one role each is enough. The
per-hive subjects are `<prefix>-<hive>` and swarm.nix reserves every
composed spelling as a hive name, so a hive cannot be named into another
hive's role.
The shared leaf stays: hive-c0re still passes it into its container, the
`bao` CLI wrapper still defaults to it, and the three
`glue-*-bao-identity.nix` files derive the PKI directory from it.
module-eval-bao-grants gains a negative arm per principal — each pins the
three stanzas the hive's leaf carried and the two wildcards a later
widening would reach for, so a policy that grows fails here rather than
in a store. Plus the consuming side: repointing a unit back at the hive's
leaf would evaluate, deploy and log in, and silently restore the union.
A hive that reads a store on another machine now places one leaf per
principal instead of one shared by four. That cost is the point, and
docs/swarm/secrets.md lists the pairs.
Nothing reads it any more: hive-c0re creates accounts as the hive's
appservice, so the mint, the host file, the bind mount, the
`LoadCredential` entry and tuwunel's `registration_token_file` all go.
⚠️ `allow_registration` has to go to `false` in the same change, and not
as hardening. tuwunel refuses to START when registration is allowed with
no token configured — it demands
`yes_i_am_very_very_sure_…_open_registration_…` instead — so dropping the
token and leaving the flag true is not a lax homeserver, it is one that
does not boot. The flag is checked only for requests arriving without an
appservice token, so hive-c0re provisions exactly as before and everyone
else is refused outright.
The swarm secret store keeps its role, repointed at the credential that
replaced the token (`swarm/hives/<hive>/matrix/appservice-token`). Its
unit now also re-runs hive-matrix's own registration renderer after
writing the file: the token is half an agreement, and a registration
still naming the previous value authenticates nobody. The renderer is
shared through an internal option rather than copied, so the
registration's shape has one home.
Both spellings of `registrationTokenFile` become
`mkRemovedOptionModule` with a message naming what replaced them. A hive
that never set the option — the default — is unaffected; one that pinned
it fails to evaluate with instructions instead of a silent no-op.
An upgraded hive needs no intervention: the activation script has both
halves in place before the homeserver restarts, existing agents keep the
tokens their devices already hold, and the old token file is left on
disk read by nothing. docs/integrations/matrix.md spells the path out.
Refs #4402
Ruled: swarm-bao-queue-agent.service must run before hive-c0re.service
and be wanted (not required) by it, so no agent container renders
ahead of the reader's attempt at its credential. An unreachable store
delays hive-c0re's start by the reader's own start-limit window rather
than failing it outright.
Refs #4314
The publisher on the authelia host has been writing
`secret/swarm/hives/<hive>/queue/agent` — the OIDC client secret agent
containers present to the swarm queue, plus the client id it belongs to —
and nothing read it. This is the reader: a oneshot `swarm-bao-queue-agent`
that logs in with the host's certificate and lands the two fields as two
files under `deploy.hive-controller.queue.agentCredentialDir`, the secret
`0600` and the client id `0644`.
Two files rather than one because that is the consumer's shape:
`swarm_queue_client::QueueConfig::from_env` takes the secret as a path and
the client id as a value, so the split here is what keeps the next slice
from parsing anything.
Same shape as the store's first reader, `glue-matrix-bao-token.nix` — a
cert login that fails loudly under `Restart=on-failure` because every state
it fails on is one a retry fixes, then reads that degrade quietly because no
retry turns "no value there" into a value. Unlike the matrix token there is
no local fallback and none is possible, so absent files mean this hive's
agents do not connect, which is the ordinary state of a swarm before the
publisher has run.
Nothing consumes the files yet and this unit is ordered `Before=` nothing.
The next slice bind-mounts them into agent containers through hive-c0re and
adds the ordering edge along with them.
Refs #3805
