Fifty-nine 422s raised off a Zod `safeParse` answered with one opaque
sentence and nothing a client could map onto a field, while the other
166 sent `details.issues` — the multi-issue envelope that exists so a
caller with three bad fields fixes all three in one round-trip. Twelve
of the fifty-nine put a dotted machine token in `error` where the
sentence belongs, so `error` was sometimes text to show a person and
sometimes a token that must not be shown, with nothing in the payload
to tell them apart.
Every one of them now answers through `apiValidationError`, which keeps
the existing `error` string and the existing `meta` byte for byte and
adds the issue list beside them. The dotted tokens keep their place in
`error` for the clients that already match on them and are published in
`meta.errorCode` as well, which is the field a machine code belongs in
and the one a new client should read.
A guard reads the route tree per refusal site rather than per file —
per file is what let this grow, since a route that used the helper once
looked compliant to a `grep -l` sweep — and asserts it still finds the
sites it judges, so a matcher that stops matching fails instead of
reporting a clean zero.
Adversarial review found the transport gate (isCookielessNativeCaller) was
broader than finishLogin's bearer predicate: a blank-UA caller with no
X-Client-Type could pass it and fall into the cookie branch, receiving a
Set-Cookie session instead of the token bundle (inert, not exploitable, but
the endpoint's own invariant was false). Also require isNativeClientRequest
so the cookie path is structurally unreachable here, and report the actual
revoke outcome on a replay so the wide event never overclaims.
Unit-test the handoff library (mint stores only the hash + binds the
challenge + 90s TTL; consume covers not-found / replay-with-revoke /
expiry-burn / PKCE-burn / atomic consume / lost-race), the
token-exchange route (rate limit, transport gate, one identical generic
401 across every invalid-code class, success with issued-hash stamp +
audit, and OIDC_ONLY does not block it), the callback native branches
(handoff mint + scheme redirect with no session, MFA ticket on the
scheme with no session/cookie, post-identity + IdP errors to the
scheme, CSRF web-fallback), the login native-param handling, and the
by-hash refresh-token revoke used for replay containment.
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.
Marc-André Bombeck