TREK/wiki/OIDC-SSO.md

OIDC / Single Sign-On

What OIDC gives you

OpenID Connect (OIDC) lets users log in with an existing identity provider — Google, Authentik, Keycloak, or any OIDC-compatible IdP — instead of a local email/password. On first SSO login, a TREK account is created automatically using the email from the provider.

User flow

1. Click "Sign in with SSO" on the login page.
2. You are redirected to your identity provider's login page.
3. Authenticate and grant consent.
4. The provider redirects back to TREK at GET /api/auth/oidc/callback. If this is your first login, an account is created automatically (subject to registration settings).
5. The server issues a short-lived one-time code and redirects your browser to /login?oidc_code=<code>. The frontend immediately exchanges that code at GET /api/auth/oidc/exchange?code=<code> to obtain the session. The code is only half of what the exchange needs: the callback also sets a one-minute HttpOnly cookie (trek_oidc_exchange) holding a secret that never appears in a URL, and the exchange requires both. A code copied out of the address bar, out of history, or out of a proxy log is therefore worthless in any other browser, and it is spent by the first attempt to redeem it whether that attempt succeeds or not. If your reverse proxy strips cookies on the way back from the identity provider, SSO login will fail here with Invalid or expired code.
6. Your trek_session cookie is set and you land on the dashboard.

Remember me. The Remember-me switch on the login page is carried into SSO as a query flag on the login URL: GET /api/auth/oidc/login?remember=1 (or remember=0), appended with & when an invite token is already present. Only 0 and 1 are accepted; any other value — and starting SSO from the register tab, where the switch is not shown — is treated as if the parameter were absent. The choice is held in the server-side login state, survives the provider round-trip and the one-time-code exchange, and decides both the session lifetime and the cookie lifetime:

remember	Session lifetime	trek_session cookie
1	SESSION_DURATION_REMEMBER (default 30d)	persistent, maxAge matches
0	SESSION_DURATION (default 24h)	browser-session cookie, cleared when the browser closes
omitted	SESSION_DURATION (default 24h)	persistent, maxAge matches

In OIDC-only mode (password login disabled) there is no switch: both the SSO button and the automatic redirect to the provider always send remember=1, so SSO sessions get the SESSION_DURATION_REMEMBER lifetime. Tune that variable if you want shorter sessions on an OIDC-only instance.

If SSO sessions are dying at browser close, the login link is sending remember=0.

Prerequisites

Set the following environment variables before starting the server:

Variable	Required	Description
APP_URL	Yes	Base URL of your TREK instance (e.g. https://trek.example.com). Used to build the redirect URI. Env var only — not configurable via the admin panel. If it is unset, TREK falls back to the first ALLOWED_ORIGINS entry, and only if that one is missing or unparseable to http://localhost:{PORT} — which produces a redirect URI your IdP will reject. A scheme-less ALLOWED_ORIGINS=trek.example.com does not parse, so it ends up on localhost too. A set but unparseable APP_URL does not fall back: the server refuses to start with Invalid environment configuration naming APP_URL.
OIDC_ISSUER	Yes	Issuer URL of your identity provider. Must use HTTPS in production.
OIDC_CLIENT_ID	Yes	OAuth 2.0 client ID registered with your IdP.
OIDC_CLIENT_SECRET	Yes	OAuth 2.0 client secret.

Register the following redirect URI with your identity provider:

<APP_URL>/api/auth/oidc/callback

For example: https://trek.example.com/api/auth/oidc/callback

Optional environment variables

Variable	Description
OIDC_DISPLAY_NAME	Label shown on the SSO button. Defaults to SSO.
OIDC_ONLY	Set to true to disable local password login and password registration. SSO login and SSO registration remain governed by their own toggles. This is an environment-variable-only setting and cannot be toggled at runtime via the admin panel.
OIDC_ADMIN_CLAIM	OIDC claim to inspect for admin role mapping. Defaults to groups. The claim value may be an array or a plain string. The claim only reaches TREK if one of the scopes in OIDC_SCOPE carries it — see Admin role mapping below. Env var only — not configurable via the admin panel.
OIDC_ADMIN_VALUE	Value that must be present in OIDC_ADMIN_CLAIM to grant the admin role. If unset, claim-based role mapping is disabled. When set, the role is re-evaluated on every login. Env var only — not configurable via the admin panel.
OIDC_SCOPE	Overrides the default scope list sent to the provider. Defaults to openid email profile. Ensure openid and email are always included, plus whichever scope carries your OIDC_ADMIN_CLAIM. Env var only — not configurable via the admin panel.
OIDC_DISCOVERY_URL	Full URL to the OIDC discovery document. Use this for providers with non-standard discovery paths (e.g. Authentik tenants). If unset, discovery is attempted at <OIDC_ISSUER>/.well-known/openid-configuration. The discovery document is cached for 1 hour.

Admin role mapping

TREK requests exactly the scopes listed in OIDC_SCOPE and nothing else, and a provider only emits a claim when a requested scope carries it. So a claim that is not covered by OIDC_SCOPE never arrives, and a claim that never arrives can never grant the admin role — no matter how OIDC_ADMIN_CLAIM is spelled.

Authentik is the usual example: groups rides the default profile scope, so it works out of the box, while entitlements has a scope of its own. Mapping admins onto an entitlement therefore takes all three variables:

OIDC_ADMIN_CLAIM=entitlements
OIDC_ADMIN_VALUE=trek-admins
OIDC_SCOPE=openid email profile entitlements

Keycloak (group and role mappers carry their own "Add to userinfo" switch) and Entra ID (optional claims) behave the same way — whatever the claim is called, check that its scope is requested.

If the configured claim is missing from the userinfo response entirely, TREK leaves the stored role untouched — a claim that never arrived is not a statement that somebody is no longer an admin — and writes one line to the server log naming the claim it looked for and the claims it did receive. Read that line first when role mapping does not do what you expect. A claim that does arrive without OIDC_ADMIN_VALUE in it still demotes on the next login; that is how the mapping takes admin away. Every role change it makes is recorded in the admin audit log.

Taking admin away

Some providers omit a claim instead of sending it empty. Okta emits a filtered groups claim only when the filter matches at least one group, and Entra ID leaves groups out for a user who is in no group at all. On those providers, removing somebody from the admin group does not demote them in TREK. Their next login carries no claim, and no claim means no verdict, so the account keeps admin for as long as it exists. Take the role away in TREK as well, in Admin → Users (Admin-Users-and-Invites) — the IdP side alone is not enough.

TREK writes a warning to the server log on every login where this happens, naming the account, so docker logs trek | grep OIDC lists the users it affects:

[OIDC] User 7 (alex) is stored as an admin and the configured OIDC_ADMIN_CLAIM "groups" was not in their userinfo response, so the admin role is kept. …

A provider that sends the claim as an empty list instead of dropping it is not affected: the empty list arrives, does not contain OIDC_ADMIN_VALUE, and demotes the account on that same login.

New-user registration via SSO

When an SSO login matches an existing TREK account by OIDC subject (sub), that account is used directly. When it matches only by email, the OIDC identity is linked to that account only if the provider asserts email_verified for it; if the claim is missing or false the login is rejected with an email_not_verified error, so an unverified address can never take over a local account. Make sure your IdP includes email_verified in the userinfo response — it is part of the email scope. If no matching account exists, TREK attempts to create one. The outcome depends on the following:

• First user ever: always created as admin, no invite required.
• Open SSO registration enabled (admin panel toggle oidc_registration): account is created as a regular user.
• Invite token present in the login URL: account is created regardless of the registration toggle. Pass the token as ?invite=<token> when initiating SSO login (e.g. GET /api/auth/oidc/login?invite=<token>).
• SSO registration disabled and no invite: login is rejected with a registration_disabled error.

Admin panel (runtime configuration)

OIDC can also be configured without environment variables via Admin → Settings, in the Single Sign-On (OIDC) card. The following fields are settable at runtime:

Field	Env var equivalent
Issuer URL	OIDC_ISSUER
Client ID	OIDC_CLIENT_ID
Client Secret	OIDC_CLIENT_SECRET
Display name	OIDC_DISPLAY_NAME
Discovery URL	OIDC_DISCOVERY_URL

Environment variables take priority over database settings when both are present.

The following variables are env var only and have no admin panel equivalent: OIDC_ONLY, OIDC_SCOPE, OIDC_ADMIN_CLAIM, OIDC_ADMIN_VALUE.

The OIDC_ONLY env var always overrides the panel's login-method toggles. To disable password login at runtime without OIDC_ONLY, use the password_login and password_registration toggles in Admin → Settings instead.

Note: The admin panel prevents you from disabling all login methods simultaneously. At least one method (password or SSO) must remain active. Similarly, you cannot remove the OIDC configuration from the admin panel while password login is disabled.

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See also: Login-and-Registration · Environment-Variables