The web OIDC flow ends in a session cookie the Bearer-transport native
client cannot consume, so on an OIDC_ONLY instance the iOS app had no
sign-in. Add a native leg: the app opens the login URL with
client=native and its own PKCE S256 challenge inside an in-app browser;
the callback resolves identity exactly as before, then mints a one-time
handoff code and 302s to the fixed compiled-in scheme
healthlog://oidc-callback (or hands back the existing MFA ticket when
the account has a second factor). The app exchanges the code plus its
PKCE verifier at POST /api/auth/oidc/native/token for the standard
native token bundle.
The return address is a compile-time constant — no redirect_uri
parameter and no env allowlist, so the open-redirect / scheme-hijack
class is removed by construction. The native flag and app challenge
travel only inside the AES-256-GCM state blob, so a network attacker or
the IdP cannot flip a web login into a native one. The handoff code is
256-bit CSPRNG, HMAC-hashed at rest, 90-second TTL, single-use via a
guarded consume; a failed PKCE check burns it. A replay of a consumed
code revokes exactly the pair the first exchange issued. The token pair
never rides a URL; only the opaque code or the MFA ticket do. The SSO
login can never satisfy requireFreshMfa step-up — the transport is
Bearer and step-up is cookie-only.
Adds the OidcNativeHandoff model (migration 0252), the token-exchange
route, a daily cleanup sweep, and the OpenAPI entry.
Every browser-facing redirect in the OIDC login/callback routes was built
from req.url. Behind a reverse proxy that doesn't forward the original
host, that reflects the address the app process was addressed as inside
the container rather than the public domain, sending users to an
unreachable internal URL after login. Route every redirect through the
trusted, operator-set NEXT_PUBLIC_APP_URL instead, matching the
convention the Withings integration already uses.
Token verification: jwtVerify now carries a closed asymmetric algorithm
allowlist (RS256/PS256/ES256/EdDSA — an HMAC alg would let anyone with
the client secret forge identities) and a 60 s clock tolerance for the
usual self-host drift between IdP and app box. The JWKS fetch — jose's
own, outside safeFetch by design — is disciplined instead by pinning
the jwks_uri host to the configured issuer's host byte-exact and
passing the same 15 s timeout safeFetch defaults to. requirePublicHost
stays deliberately unused on this surface: LAN/Tailscale-only IdPs are
a legitimate topology and the issuer is operator config, not user
input.
Discovery: the issuer comparison now tolerates exactly one trailing
slash on either side (a recurring IdP/operator mismatch); token
verification still matches the provider-sent issuer byte-exact.
State cookie: the cookie is set under Path=/api/auth/oidc but was
deleted without a path — RFC 6265 keys cookies by (name, domain,
path), so the deletion never matched and the single-use blob survived
its whole TTL. Every delete now repeats the exact path, via a shared
constant.
Also: the IdP error code recorded in the wide event is whitelisted
against the closed OAuth error-code set (unknown values collapse to
"other"); the status route drops an unreachable try/catch and a
duplicated annotate; the passkey conditional-UI autofill stays unarmed
under OIDC_ONLY (passkey login is a server-enforced dead end there);
env-manifest gains the three optional OIDC_* tuning vars; the env
example notes why the issuer should be HTTPS.
Adds an OpenID Connect relying-party login path (PKCE authorization-code
flow) against a single env-configured identity provider — additive to
password/passkey login by default, with an operator opt-in (OIDC_ONLY,
enforced server-side on every auth route) to disable them entirely.
First-time sign-in auto-provisions or links an account by verified email.
Closes an open redirect in the post-login `next` parameter (both the new
OIDC path and the pre-existing password/passkey flow shared the same
backslash-normalization bypass) by resolving the target through a real
URL parse and comparing origins instead of a prefix check.
Marc-André Bombeck