hermes-agent/hermes_cli/dashboard_auth
Ben b26d81d536 feat(dashboard-auth): honour X-Forwarded-Prefix + __Host-/__Secure- cookies
Mission-control style deploys reverse-proxy the dashboard at a path
prefix (e.g. mission-control.tilos.com/hermes/* -> :9119) and inject
X-Forwarded-Prefix: /hermes on every request. The SPA mount already
honoured this for asset URLs and the bootstrap __HERMES_BASE_PATH__,
but the OAuth gate didn't:

  1. The gate's Location: header to /login and the 401 envelope's
     login_url were built bare ("/login?next=..."). Under a /hermes
     prefix the browser follows that to mission-control.tilos.com/login
     which the proxy doesn't route to the dashboard.
  2. _redirect_uri (the OAuth callback URL handed to the IDP) used
     request.url_for() which doesn't honour X-Forwarded-Prefix
     (Starlette/uvicorn only proxy_headers Host + Proto + For). The
     IDP redirects back to /auth/callback instead of /hermes/auth/
     callback → 404 in the user's browser.
  3. Cookies were set with Path=/ which leaks them to other apps on
     the same origin and won't be sent back on requests under the
     prefix in the first place.

Fix threads the normalised prefix through every boundary:

  * New hermes_cli/dashboard_auth/prefix.py — single source of truth
    for X-Forwarded-Prefix parsing. web_server._normalise_prefix
    becomes a re-export so the SPA mount, the gate, and the cookies
    helper all agree.
  * middleware._unauth_response builds login_url = f"{prefix}/login".
  * routes._redirect_uri splices the prefix into the path component
    of the IDP-bound URL (with full validation of the header).
  * cookies.{set,clear}_{session,pkce}_cookie now take prefix="".
    Path attribute switches to /hermes when set; cookie name switches
    name variant (see below). Every caller passes the request's
    normalised prefix.

Cookie hardening (Teknium's lesser-note #1 in the PR review): adopt
the __Host- / __Secure- cookie name prefixes per draft-west-cookie-
prefixes. The variant is selected from (use_https, prefix):

  * Loopback HTTP → bare "hermes_session_at" (both prefixes require
    Secure, incompatible with HTTP).
  * HTTPS, direct deploy (Path=/) → "__Host-hermes_session_at".
    Strongest spec: bound to exact origin, no Domain attribute, Secure
    required.
  * HTTPS, behind a proxy prefix (Path=/hermes) →
    "__Secure-hermes_session_at". __Host- forbids Path != "/"; the
    explicit Path=/hermes covers same-origin app isolation.

Setter and reader BOTH consult the prefix because the cookie *name*
changes — a reader that looked up the bare name when the setter wrote
__Secure- would never find the value. The reader falls back across
all three variants so a request whose shape changed mid-session (e.g.
post-deploy from no-prefix to /hermes) still picks up the existing
cookie until it expires.

Test coverage:

  - tests/hermes_cli/test_dashboard_auth_prefix.py — new file. 11 tests
    pinning:
      • Location: /hermes/login on the gate's HTML redirect
      • 401 envelope login_url carries the prefix
      • Malformed X-Forwarded-Prefix is ignored (header-injection
        defence; the script-tag value is normalised to empty string)
      • _redirect_uri splices /hermes into the path (the property
        that prevents the IDP-returns-to-404 failure)
      • PKCE cookie uses Path=/hermes + __Secure- when proxied
      • Session cookies use __Host- when direct, __Secure- when
        proxied, bare on loopback HTTP
      • End-to-end round trip with hand-managed PKCE cookie carriage
        (TestClient can't simulate a Path=/hermes cookie automatically)
  - tests/hermes_cli/test_dashboard_auth_cookies.py — rewritten to pin
    each (use_https, prefix) shape produces its expected cookie name,
    plus reader-side coverage that __Host- and __Secure- variants are
    both recognised.
  - Existing tests across middleware / 401-reauth / etc. updated to
    match the new cookie names (substring contains instead of
    startswith).

Mutation-tested: reverting _unauth_response to build the bare
"/login" URL trips exactly the two tests that pin the prefix
carriage, confirming the suite discriminates the regression.
2026-05-27 02:12:27 -07:00
..
__init__.py feat(dashboard-auth): define DashboardAuthProvider ABC + Session dataclass 2026-05-27 02:12:27 -07:00
audit.py feat(dashboard-auth): single-use WS tickets + POST /api/auth/ws-ticket 2026-05-27 02:12:27 -07:00
base.py feat(dashboard-auth): define DashboardAuthProvider ABC + Session dataclass 2026-05-27 02:12:27 -07:00
cookies.py feat(dashboard-auth): honour X-Forwarded-Prefix + __Host-/__Secure- cookies 2026-05-27 02:12:27 -07:00
login_page.py fix(dashboard-auth): propagate next= through login page + PKCE cookie 2026-05-27 02:12:27 -07:00
middleware.py feat(dashboard-auth): honour X-Forwarded-Prefix + __Host-/__Secure- cookies 2026-05-27 02:12:27 -07:00
prefix.py feat(dashboard-auth): honour X-Forwarded-Prefix + __Host-/__Secure- cookies 2026-05-27 02:12:27 -07:00
registry.py feat(dashboard-auth): define DashboardAuthProvider ABC + Session dataclass 2026-05-27 02:12:27 -07:00
routes.py feat(dashboard-auth): honour X-Forwarded-Prefix + __Host-/__Secure- cookies 2026-05-27 02:12:27 -07:00
ws_tickets.py feat(dashboard-auth): single-use WS tickets + POST /api/auth/ws-ticket 2026-05-27 02:12:27 -07:00