parking_solution/wiki/entities/local-jwt-auth.md

type, tags, sources, updated

type	tags	sources	updated
entity	parking stack auth offline-first	parking-system-architecture	2026-06-15

Local JWT Auth

Authentication and authorization, kept fully local — a direct consequence of offline-first (an air-gapped park cannot reach an external identity provider; see logto-zitadel-oidc for the rejected alternative). (See parking-system-architecture §2.)

• @fastify/jwt signs tokens with a local secret (symmetric HMAC). The server refuses to start without a strong JWT_SECRET (≥32 chars, no placeholder) — there is deliberately no insecure default.
• Session lifetime: valid until explicit logout — no time expiry (decision 2026-06-15, built). Booth reality breaks any fixed clock: relief arrives late, fails to show, or one operator is forced to work two shifts in a row — a token that expired mid-duty would strand an active operator. So the login persists until logout; a shift is a separate, explicit boundary, not tied to token lifetime. (Superseded the earlier "8h expiry, bound to a shift" assumption.) The JWT carries no exp; the cookie has a long fixed maxAge (30 days) so a browser restart doesn't log out an active operator, and logout clears it.
• A users table in sqlite holds bcrypt password hashes plus a role_id FK. The first admin is seeded via pnpm --filter @parking/server seed-admin (no bootstrap endpoint); every other user is created in-app (admin → Users screen).
• Authorization = dynamic RBAC (built 2026-06-18, replacing the old hardcoded admin/operator/cashier/readonly enum — those are now ordinary seed roles). Roles are data: roles + role_permissions tables, composed by an admin from a code-defined permission grid (@parking/shared PERMISSIONS = resource:action, e.g. tariff:update, payment:create, event:void). A preHandler requirePermission(...) per route checks a PERMISSION, not a role name. The JWT carries roleId (not the permission list); the guard resolves the role's permission set per-request from an in-memory cache (bumpPermsCache() on any role write), so editing a role applies immediately — no re-login, no token bloat. No Casbin/engine needed at this scale.
• Protected built-in admin role (id='admin', builtin=1): non-editable, non-deletable, and always resolves to the FULL permission set in code. The app refuses to delete or downgrade the last user holding admin — administration can never be locked out of the appliance.
• event:void is a permission, NOT a ledger delete: the append-only signed chain is untouched; the permission only gates who may APPEND a void event (there is no void API route yet — forward seam).
• The grid is extensible — adding a feature adds its resource:action rows. Latest: log:read (a new log resource) gates the diagnostic-log viewer (GET /api/logs); admin holds it, and it's grantable to a diagnostic role. See app-logs.
• No privilege escalation through the RBAC system itself. role:create/role:update and user:create/user:update are themselves grantable, so a non-admin could otherwise self-escalate. Guards (routes/roles.ts, routes/users.ts): a caller may only put permissions on a role that they already hold, and may only assign/modify users whose role is a SUBSET of the caller's own (so no minting a privileged role, handing out the admin role, or resetting/deleting a more- privileged account). An admin holds the full set, so it is unrestricted — the intended behaviour.

Cookie session (browser auth)

The SPA never sees the JWT. Login (POST /api/auth/login) verifies bcrypt and sets two cookies:

• parking_token — the JWT, HttpOnly + SameSite=Strict (+ Secure when NODE_ENV=production). JS can't read it; @fastify/jwt reads it from the cookie, not the Authorization header.
• parking_csrf — a random token, readable by JS. The JWT also carries a matching csrf claim. On every mutation the SPA echoes the cookie in the X-CSRF-Token header; the guard requires header == cookie == the signed claim (double-submit CSRF). Safe reads are exempt.

Routes: login, logout (clears cookies), me (bootstraps SPA session on load). The dev react-vite-spa proxy and the prod nginx reverse proxy keep the SPA and API same-origin, so the cookies work without CORS. (This replaced an earlier dev-only SETUP_AUTH_BYPASS shim, now removed.)

Open decision: moving from the symmetric secret to an asymmetric key (RS256/EdDSA) so verifying hosts hold only a public key — open-questions #7. Relevant before any multi-host/multi-lane deployment.

Part of the technology-stack. License: MIT.