auth-bundle-2 Phase 7 + Phase 7.5: OIDC first-admin bootstrap +

break-glass admin (Argon2id, lockout, default-OFF, surface-invisibility)

Phase 7 — OIDC first-admin bootstrap (Decision 3):

  - Optional AdminBootstrapHook closure on *oidc.Service. When wired,
    HandleCallback consults the hook AFTER group resolution + user
    upsert and BEFORE the empty-mapping fail-closed check. Hook
    receives (providerID, groups, userID); returns grantAdmin=true
    when the user matches CERTCTL_BOOTSTRAP_ADMIN_GROUPS AND no
    admin exists yet in the tenant.
  - cmd/server/main.go wires the hook as a closure that:
      * Filters by CERTCTL_BOOTSTRAP_OIDC_PROVIDER_ID (if configured).
      * Probes AdminExists via authActorRoleRepo (admin-already-exists
        silently returns false; bootstrap mode is one-shot per tenant).
      * Walks group intersection.
      * On match: grants r-admin via authActorRoleRepo.Grant + emits
        the bootstrap.oidc_first_admin audit row with
        event_category=auth + INFO log.
  - Coexists with the Bundle 1 env-var-token bootstrap. Both paths
    can be configured; first match wins (admin-existence probe
    short-circuits the second).
  - HandleCallback's empty-mapping fail-closed check moved AFTER the
    hook so a fresh deployment with zero group_role_mappings can
    still mint the first admin.
  - 5 tests in service_test.go: hook grants admin on match, hook
    returns false preserves empty-mapping fail-closed, admin-already-
    exists silently falls through to normal mapping, hook-error wraps
    + bubbles, idempotent when admin is already in the mapped role set.

Phase 7.5 — Break-glass admin (Decision 4, default-OFF):

Migration 000038 ships:

  - breakglass_credentials table — at-most-one-credential-per-actor
    (UNIQUE(actor_id)), Argon2id PHC-format password_hash, lockout
    state machine (failure_count, locked_until, last_failure_at).
    FK CASCADE on users(id) so deleting a user atomically removes
    their credential.
  - Two new permissions seeded into r-admin only:
      auth.breakglass.admin — set/rotate/unlock/remove credentials.
      auth.breakglass.login — actor uses break-glass to log in.
    CanonicalPermissions extended in lockstep.

internal/auth/breakglass/service.go (~580 LOC):

  - Service.Enabled() reflects CERTCTL_BREAKGLASS_ENABLED.
  - SetPassword: Argon2id with OWASP 2024 params (m=64MiB, t=3, p=4,
    salt=16 random bytes, output=32 bytes); per-password random salt;
    PHC-format hash output. Min 12 / max 256 byte input.
  - Authenticate: constant-time-compare via subtle.ConstantTimeCompare
    on every code path. Identical 401 + identical timing across the
    wrong-password / locked-account / non-existent-actor paths so an
    attacker cannot probe whether a given actor has break-glass
    configured. Non-existent-actor + locked-account paths run a
    verifyDummy() Argon2id pass for timing parity. Lockout state
    machine: failure_count++ on every wrong attempt; threshold (default
    5) trips locked_until = NOW() + duration (default 15m). Successful
    Authenticate resets the counter. Reset-window: failures aged out
    after CERTCTL_BREAKGLASS_LOCKOUT_RESET_INTERVAL (default 1h)
    auto-reset on next attempt.
  - Unlock + RemoveCredential: admin-only (auth.breakglass.admin
    gated at the router via rbacGate). Audit rows on every operation.
  - All public methods refuse to act when Enabled()==false (returns
    ErrDisabled; the handler maps to HTTP 404 — surface invisibility).

internal/repository/postgres/breakglass.go ships the 5-method
postgres impl with atomic single-statement IncrementFailure (so
concurrent racing wrong-password attempts can't observe an
intermediate state and slip past the threshold) and idempotent
ResetFailureCount.

internal/api/handler/auth_breakglass.go ships the 4-endpoint HTTP
surface:

  - POST /auth/breakglass/login (auth-exempt; 5/min rate-limited per
    source IP via the existing rate limiter; returns 404 when
    disabled). On success sets the post-login session cookie + CSRF
    cookie via SessionService.Create + 204. On any failure:
    uniform 401 + identical timing (the service has already audited
    the specific failure category).
  - POST /api/v1/auth/breakglass/credentials (auth.breakglass.admin)
  - POST /api/v1/auth/breakglass/credentials/{actor_id}/unlock
    (auth.breakglass.admin)
  - DELETE /api/v1/auth/breakglass/credentials/{actor_id}
    (auth.breakglass.admin)

Admin endpoints share the surface-invisibility property: when
CERTCTL_BREAKGLASS_ENABLED=false, every admin endpoint also returns
404 (not 403) so probing via the admin surface gets the same signal
as probing the login endpoint.

Tests (internal/auth/breakglass/service_test.go):

All 8 Phase 7.5 spec-mandated negative cases:

  1. Service.Enabled()==false → all ops return ErrDisabled.
  2. Wrong password → ErrInvalidCredentials, failure_count++,
     audit row with event_category=auth.
  3. Failure_count exceeds threshold → locked, subsequent attempts
     (including with the CORRECT password) return identical-shape
     401 while the lockout window holds.
  4. Lockout window expires → next attempt with correct password
     succeeds + resets the counter.
  5. Password < 12 bytes (or > 256 bytes) → ErrWeakPassword.
  6. Password leak hygiene — the service has zero slog calls; the
     audit-row map literal never includes the password plaintext.
  7. Argon2id hash never appears in logs OR API responses — pinned
     by `json:"-"` tag on BreakglassCredential.PasswordHash + a
     belt-and-braces json.Marshal probe asserting the hash bytes
     never appear in the marshaled output.
  8. Constant-time-compare verified via timing-statistical test —
     wrong-password vs no-credential paths take statistically
     indistinguishable time (within 5x ratio). The verifyDummy()
     hash compute on the no-credential + locked paths is what
     keeps timing parity; absent that, an attacker could side-
     channel "actor doesn't have a credential" via timing.

Plus coverage-lift batch covering: SetPassword first-time vs rotate,
no-caller-id rejection, no-target-id rejection, RNG failure surface,
Authenticate happy-path mints session, no-credential audit row,
session-mint-failure surface, FailureResetInterval recycle, Unlock
+ RemoveCredential happy paths, hash-format unit tests (round-trip,
mismatch, malformed/wrong-version/bad-base64 formats), nil-audit +
nil-session pass-through.

Coverage on internal/auth/breakglass/ at 91.5% per-statement (above
the Phase 7.5 spec ≥ 90% floor).

cmd/server/main.go wiring:

  - Constructs breakglassRepo + breakglassService + breakglassHandler
    after the OIDC service block.
  - breakglassSessionMinterAdapter shim bridges *session.Service.Create
    to the breakglass.SessionMinter port.
  - Logs WARN at boot when CERTCTL_BREAKGLASS_ENABLED=true (operator
    visibility for the deliberate SSO-bypass).

internal/config/config.go gains:

  - AuthConfig.BootstrapAdminGroups + BootstrapOIDCProviderID for
    Phase 7 (CERTCTL_BOOTSTRAP_ADMIN_GROUPS comma-list +
    CERTCTL_BOOTSTRAP_OIDC_PROVIDER_ID).
  - AuthConfig.Breakglass nested struct with 4 env vars
    (CERTCTL_BREAKGLASS_ENABLED + LOCKOUT_THRESHOLD + LOCKOUT_DURATION
    + LOCKOUT_RESET_INTERVAL).

Router wiring:

  - 4 new breakglass routes registered when reg.AuthBreakglass != nil;
    public login route via direct r.mux.Handle (auth-exempt), 3 admin
    routes via r.Register + rbacGate(auth.breakglass.admin).
  - POST /auth/breakglass/login pinned in AuthExemptRouterRoutes
    allowlist with Phase 7.5 justification.
  - SpecParityExceptions extended with 4 new entries documenting
    the Phase 7.5 deferral of full per-endpoint OpenAPI rows
    (handler doc-block at the top of auth_breakglass.go is the
    operator-facing reference).

Threat model (encoded in service.go + auth_breakglass.go doc-blocks
+ migration 000038 docstrings, to be promoted to docs/operator/auth-
threat-model.md in Phase 12):

  - Break-glass is a deliberate bypass of the SSO security boundary.
    An attacker who phishes the password OR finds it in a compromised
    password manager bypasses MFA, OIDC, and every group-claim gate.
  - Recommendation: keep CERTCTL_BREAKGLASS_ENABLED=false in steady-
    state. Enable only during SSO-broken incidents. Disable after
    recovery.
  - WebAuthn pairing (v3 per Decision 12) is the load-bearing second
    factor. Without it, break-glass is best treated as an emergency-
    only path.
  - Audit trail surfaces every break-glass action under
    event_category=auth; the auditor role can monitor for unexpected
    break-glass logins.

Verifications: gofmt clean, go vet clean across all touched packages,
go test -short -count=1 green across internal/auth/oidc (3.0s; new
Phase 7 hook tests integrated alongside the 21+ Phase 3 negatives),
internal/auth/breakglass (3.6s; 8 spec-mandated negatives + coverage
batch passing), internal/config + internal/domain/auth + internal/api/
router + internal/api/handler all green, no regressions in Bundle 1
packages.

internal/auth/oidc/service.go

@@ -79,6 +79,12 @@ type Service struct {
 	mu       sync.RWMutex
 	cache    map[string]*providerEntry // keyed by provider ID
 	clockNow func() time.Time          // injectable for tests
+
+	// adminBootstrapHook is the optional Phase 7 first-admin bootstrap
+	// closure. When set, HandleCallback consults it after group
+	// resolution + user upsert; on grantAdmin=true the user's resolved
+	// role IDs are extended with r-admin. See bootstrap_hook.go.
+	adminBootstrapHook AdminBootstrapHook
 }
 
 // providerEntry caches the go-oidc Provider + the OAuth2 config + the
@@ -503,14 +509,14 @@ func (s *Service) HandleCallback(
 		}
 	}
 
-	// Step 9: map groups to role IDs. Empty result => fail closed.
+	// Step 9: map groups to role IDs. Phase 7 defers the empty-mapping
+	// fail-closed check until after the bootstrap hook gets a chance to
+	// grant r-admin (Step 11) — a fresh deployment with zero group_role_
+	// mappings still needs to mint the first admin.
 	roleIDs, err := s.mappings.Map(ctx, providerID, groups)
 	if err != nil {
 		return nil, fmt.Errorf("oidc: group-role mapping lookup: %w", err)
 	}
-	if len(roleIDs) == 0 {
-		return nil, ErrGroupsUnmapped
-	}
 
 	// Step 10: upsert the user record. Per Phase 1 contract, identity
 	// is per-(provider, oidc_subject); a person logging in via a new
@@ -520,7 +526,31 @@ func (s *Service) HandleCallback(
 		return nil, fmt.Errorf("oidc: upsert user: %w", err)
 	}
 
-	// Step 11: mint a post-login session via Phase 4's SessionService.
+	// Step 11 — Phase 7: OIDC first-admin bootstrap hook. Optional;
+	// runs after upsertUser. The hook checks AdminExists + group
+	// intersection against CERTCTL_BOOTSTRAP_ADMIN_GROUPS; on first
+	// match it grants r-admin to the user via ActorRoleRepository
+	// + emits a bootstrap.oidc_first_admin audit row + returns
+	// grantAdmin=true so we ensure r-admin lands in the role set.
+	// Subsequent logins (admin-already-exists) silently skip via
+	// grantAdmin=false.
+	if s.adminBootstrapHook != nil {
+		grantAdmin, herr := s.adminBootstrapHook(ctx, providerID, groups, user.ID)
+		if herr != nil {
+			return nil, fmt.Errorf("oidc: admin bootstrap: %w", herr)
+		}
+		if grantAdmin {
+			roleIDs = appendIfMissing(roleIDs, "r-admin")
+		}
+	}
+
+	// Step 12: empty-mapping fail-closed. Phase 3 contract preserved —
+	// deferred from Step 9 only to give the bootstrap hook a chance.
+	if len(roleIDs) == 0 {
+		return nil, ErrGroupsUnmapped
+	}
+
+	// Step 13: mint a post-login session via Phase 4's SessionService.
 	cookieValue, csrfToken, err := s.sessions.MintForUser(ctx, user, roleIDs, ip, userAgent)
 	if err != nil {
 		return nil, fmt.Errorf("oidc: session mint: %w", err)