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.
Contract V1 of nous-account-service PR #180 ships no refresh tokens, so
the original Phase 6 silent-refresh design is replaced with a thinner
'401 → redirect to /login' UX. The dashboard's gated middleware now
emits a structured envelope on any auth failure; the SPA's fetch
wrapper sees it and full-page-navigates the user through re-auth.
hermes_cli/dashboard_auth/cookies.py:
set_session_cookies(refresh_token='') SKIPS writing the
hermes_session_rt cookie. Forward-compat: a non-empty refresh_token
still emits the cookie unchanged, so a future Portal contract that
starts issuing RTs flips the persistence on with no other change.
clear_session_cookies still emits a Max-Age=0 deletion for the RT
cookie so stale cookies from earlier deployments get flushed on
logout / session expiry. Deprecation marker + rationale in
module docstring per the user's docstring-only deprecation pattern.
hermes_cli/dashboard_auth/middleware.py:
_unauth_response now builds a structured JSON envelope for API 401s:
{ error: 'session_expired' | 'unauthenticated',
detail: 'Unauthorized',
reason: <internal>,
login_url: '/login?next=<safe-path>' }
HTML redirects also carry next= so a user landing on /sessions
without a cookie bounces back to /sessions after re-auth.
_safe_next_target validates same-origin: drops protocol-relative
paths (//evil.com), absolute URLs, and any /login or /auth/* loop.
Dead cookies are cleared on the 401 path so the browser stops
replaying invalid tokens.
hermes_cli/dashboard_auth/routes.py:
/auth/callback accepts next= query param and validates via
_validate_post_login_target (same rules as the gate's
_safe_next_target — defence-in-depth because next= survived a full
IDP round trip and attacker-controlled state can re-enter via the
callback URL). Open-redirect attempts land at '/' instead.
web/src/lib/api.ts:
fetchJSON parses the 401 envelope and full-page-navigates to
body.login_url ONLY on the known session-expiry error codes.
Domain-level 401s (e.g. permission errors) bubble up as regular
errors. credentials: 'include' added so cookie auth works for all
fetches routed through this wrapper. sessionStorage.lastLocation is
preserved for future use by AuthWidget / hermes_status.
Test files marked with pytest.mark.xdist_group so the four files that
mutate web_server.app.state.auth_required serialize onto the same xdist
worker — eliminates 'works locally, fails in CI' app-state bleed.
20 new tests in test_dashboard_auth_401_reauth.py:
- set_session_cookies(refresh_token='') skips RT cookie
- clear_session_cookies still emits RT deletion
- 401 envelope shape (unauthenticated vs session_expired)
- dead cookie cleared on invalid-token 401
- login_url carries next= for deep paths
- login loop avoided when path is /login/auth/api-auth
- protocol-relative URL rejected
- _safe_next_target unit tests (accept same-origin, reject loops/abs)
- /auth/callback respects safe next= but rejects open redirects
2 pre-existing tests updated to accept the new /login?next=%2F shape.
Full dashboard-auth suite: 168 passed, 1 skipped (Phase 0 pre-existing).
Phase 3, Task 3.1. Three cookies:
- hermes_session_at: OAuth access token (HttpOnly, TTL = token TTL)
- hermes_session_rt: OAuth refresh token (HttpOnly, 30d max-age)
- hermes_session_pkce: PKCE state + verifier + provider hint (10min)
All SameSite=Lax + Path=/. Secure flag is set ONLY when the request
scheme is https — uvicorn proxy_headers=True (enabled in gated mode at
Phase 3.5) rewrites scheme from X-Forwarded-Proto so Fly's TLS
terminator works.
