Fixes from review of the device flow / introspection / DCR work:
Introspection over-disclosure (RFC 7662):
- Restrict introspection to authorized callers — the client a token was issued
to, or a resource server registered (resource_identifiers) to serve the token's
bound RFC 8707 audience. Unauthorized callers get {active:false}, disclosing
nothing, instead of any confidential client reading any token.
- Scope-gate disclosed claims: username only with the email scope, groups only
with the groups scope (mirrors userinfo). ADR 0005.
Tokens minted for revoked users:
- Re-check application.user_allowed?(user) at mint time in the device, refresh,
and authorization-code grants (covers app-active, user-active, group
membership). A user deactivated or removed from the allowed group between
approval and the token request is refused with access_denied. The refresh
check runs before rotation so a denied refresh has no side effects.
Device authorization hardening:
- Require confidential clients to authenticate, and require PKCE (code_challenge)
up front for clients that require it, so an intercepted device_code plus a
known public client_id cannot redeem tokens.
- Merge (not overwrite) the shared consent record on device approval.
Tests: new oidc_introspection_test and oidc_mint_authorization_test; existing
PKCE/claims tests updated to grant app access (they created ungrouped apps and
relied on the token endpoint not checking authorization). Full suite green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F7cwhwDJp3MJJDoNPVE6zq
Clients can name a target resource server via the `resource` parameter at the
authorization and device-authorization endpoints. Clinch binds it to the issued
token as its audience and reports it at introspection as `aud`, so a token minted
for one API cannot be replayed against another that also trusts clinch.
- `resource` is validated syntax-only (absolute URI, no fragment) — pass-through,
no resource registry; the resource server enforces the audience on introspection
- threaded from authorize / device_authorization onto the auth/device code, then
the access and refresh tokens, and carried across refresh rotation
- invalid values are rejected with error=invalid_target
- introspection `aud` is the bound resource, falling back to the client_id
- ADR 0004 records the pass-through-vs-registry decision
Completes the clinch-side OAuth surface for MCP connectors (with DCR +
introspection); Protected Resource Metadata (RFC 9728) lives on the resource server.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F7cwhwDJp3MJJDoNPVE6zq
Adds three OAuth surfaces to the OIDC provider so CLIs, terminal agents, and
MCP connectors can authenticate as real users instead of using static API keys.
Device Authorization Grant (RFC 8628):
- OidcDeviceCode model (HMAC device_code, short plaintext user_code, nullable
user until approval, slow_down polling state), mirroring OidcAuthorizationCode
- POST /oauth/device_authorization issues the code pair + verification URIs
- device_code grant on /oauth/token returns authorization_pending / slow_down /
access_denied / expired_token, then the standard token triple; single-use
- Authenticated /device approval page, gated by Application#user_allowed?
Token Introspection (RFC 7662):
- POST /oauth/introspect: confidential-caller-authenticated; returns active,
scope, and the user's groups so resource servers can authorize on membership
Dynamic Client Registration (RFC 7591):
- POST /oauth/register creates public/confidential clients (PKCE required)
- Runtime toggle via a new Setting store + admin switch on the Applications page;
off by default, env var CLINCH_DCR_ENABLED as bootstrap fallback
- New clients are default-deny (no allowed_groups) until an admin grants access
- RFC 8414 metadata alias at /.well-known/oauth-authorization-server;
registration_endpoint advertised only while the window is open
Discovery advertises all three grants/endpoints. Seeds add a clinch-cli public
client and a c2a2-introspection confidential client. ADRs in docs/decisions
record the opaque-vs-JWT, device-flow, and DCR-security decisions.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F7cwhwDJp3MJJDoNPVE6zq
