tegwick
329e48f64a
KEY-WP-0013-T05's tenant blocker did not need the decision it was waiting on. The two proposed resolutions differ in where a human's tenant comes from -- the directory record, or the client registration -- and an implementation exists that is correct under either, so the choice can be made later without another migration. A client registration may now declare a tenant. humanTenant() resolves it by four rules: no declaration keeps the directory answer unchanged; a declared zone applies where the directory has placed the user nowhere; agreement passes; and a declared zone conflicting with a directory assignment refuses issuance rather than relabelling the user. The refusal is the design, not an edge case. A registration can bind a zone for unplaced users and can never move a placed one, so this gets the approval chain its tenant:platform without writing a general cross-tenant override into the issuer. It fails closed rather than picking a winner, because either answer would be a silent cross-tenant assertion, and it reports 403 with error_type: tenant_binding so an operator can tell a misconfigured registration from a rejected login. If the owners later populate directory tenants, the same code stops supplying the zone and starts enforcing agreement with it. Safe only because client registrations are static and deployment-owned. The tenant contract records that this rule must be revisited if dynamic client registration is ever admitted. Tests cover all four rules; neutering the conflict check fails the relabel test rather than passing silently. T05 now waits on one thing only: the client_id and callback URI from informed-decision once it has a deployed origin. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016uV8zoCKpA1WRAxsKRYbdH Assistant: claude-code Assistant-Model: opus Assistant-Process: 1182213@bnt-lap001 Assistant-Session: 966597b9-ae61-46a4-8b9e-1594ab3ec4ad
5 KiB
Approval-engine token contract
Static client registrations may set audience: approval-engine. This selects
only the access-token audience; OIDC ID tokens retain aud=clientId. Omitting
audience preserves the existing client-ID access audience, including OpenBao
consumers. Request audience and resource parameters cannot override it.
Access tokens contain the granted scope string for both supported grant types.
config/service-clients.example.yaml provides the two requested confidential
clients: secrets-engine-approval gets read/consume, and approval-engine-operator
gets lifecycle/observation scopes without consume. Service tokens contain
principal_type=service, tenant, roles, scope, assurance, issuer, subject,
audience, issue time and expiry; the lifetime is 15 minutes. The issuer signs
with RS256 and publishes its public key through /jwks.
Human approvers need a separate authorization-code/PKCE registration with an
exact deployment-owned callback, audience: approval-engine,
allowedScopes: [openid, approval:read, approval:approve], and
mfaRequired: true. Do not add consume or other approval grants to that client.
No callback is invented here. The ID token is for the login client; present the
access token to approval-engine.
That client must also declare tenant: tenant:platform. A human token's tenant
comes from the directory record, which assigns none today, so without the
declaration the token would carry tenant:coulomb and be refused here. See
the tenant contract for the four resolution rules and
for why a declared zone can never relabel a user the directory has placed.
approval:read is present because approval-engine showed the surface cannot
render a decision without it: GET /v1/approvals/{id} and /claim both require
it, so the earlier [openid, approval:approve] would have let an approver submit
an entry they were never able to display. Reading through the owning component's
own service identity would also work, but it weakens the one claim that surface
exists to make — evidence of what this person was shown — so the read is
granted to the human principal instead. approval:consume stays excluded: human
principals are refused consume in approval-engine's code regardless, and
consumption belongs to the PEP causing the side effect.
The assurance object
KeyCape emits assurance on every human token, unscoped. approval-engine stores
it verbatim into the approval entry, where it is the only place mfaRequired: true survives into the record, so its shape is a contract:
| Field | Type | Meaning |
|---|---|---|
level |
string | aal1 or aal2. aal2 exactly when MFA was verified in this authorization. The closest thing to acr. |
methods |
string[] | ["pwd"], or ["pwd","otp"] when MFA was verified. The closest thing to amr. |
mfa |
bool | Whether MFA was verified. Redundant with level by construction, and kept because a consumer asserting on one should not have to know the mapping. |
source |
string | Always key-cape. Names which issuer made the assertion. |
at |
number | Unix seconds at which the user authenticated — not when the token was minted. |
at is authentication time on purpose. A reused browser session can be hours
old, and a record saying MFA happened at mint time would overstate how recently
the person proved anything. Where an authorization rides an existing session, the
original login instant is carried through.
The level is derived from what happened in this authorization, never from
enrollment state: a user with MFA enrolled who was not challenged gets aal1.
A consumer that needs a maximum age should compare at, not assume freshness.
These fragments are not live registrations. The two service registrations require
custody-managed values for the named environment references and a reviewed
rollout of this version, including the upstream issuer precondition. Platform's
CCR-2026-0017/0018 use OpenBao field CLIENT_SECRET; their approval remains open.
The separate human registration needs its actual UI-owned callback. A bearer-only
approval resource server has no such callback; its absence does not prevent
service-client issuance or service startup, and service credentials cannot be
counted as human approval evidence. Never log the token or secret. Verify the resulting
access token against the deployed issuer's /jwks, checking issuer, audience,
expiry, subject, principal type, tenant, roles, scope and assurance. Verify that
operator consume and human consume requests are rejected. Local tests verify
signatures against the JWKS handler; they do not constitute live issuance proof.
Negative verification requires the token endpoint's typed refusal: HTTP 400,
invalid_profile_usage, feature scope for excess scope; HTTP 401 with feature
Authorization for a predecessor secret. A timeout, 5xx, malformed response,
invalid signature or JWKS failure is not proof of denial.
KeyCape owns issuance and client grants/disablement. OpenBao and the deployment operator own credential custody; approval-engine enforces its resource policy.