How Mastodon Configured Login Using SSO

Question

How Mastodon configure login using SSO, such as openid with keycloak? I search in Github and configure Mastodon follow this guide, but it doesn't work.

This is my environment variable:

OIDC_ENABLED=true
OIDC_DISPLAY_NAME=SSO
OIDC_AUTH_ENDPOINT=https://SSO_URL/realms/mastodon/.well-known/openid-configuration
OIDC_ISSUER=https://SSO_URL/realms/mastodon
OIDC_DISCOVERY=true
OIDC_SCOPE="openid,profile"
OIDC_UID_FIELD=uid
OIDC_CLIENT_ID=masto
OIDC_REDIRECT_URI=https://MASTODON_URL/auth/auth/openid_connect/callback
OIDC_SECURITY_ASSUME_EMAIL_IS_VERIFIED=true
OIDC_CLIENT_SECRET=***

I checked the error log via this command but it is empty.

docker-compose logs | grep ERROR

Even the text of the SSO button has not changed.

There is the screenshot of sso button

Answer 1

my config:

OIDC_ENABLED=true
OIDC_DISPLAY_NAME=My IDM
OIDC_DISCOVERY=true
OIDC_ISSUER=https://<keycloak_url>/auth/realms/<real>
OIDC_AUTH_ENDPOINT=https://<keycloak_url>/auth/realms/<real>/.well-known/openid-configuration
OIDC_SCOPE=openid,profile,email
OIDC_UID_FIELD=preferred_username
OIDC_CLIENT_ID=<client id>
OIDC_CLIENT_SECRET=<client secret>
OIDC_REDIRECT_URI=https://<mastodon URL>/auth/auth/openid_connect/callback
OIDC_SECURITY_ASSUME_EMAIL_IS_VERIFIED=true

Tested with Mastondo 3.5.3 and Keycloak 7.0.1

Maybe, only change yours OIDC_SCOPE and OIDC_UID_FIELD environments values.

Answer 2

I cannot comment but Erik suggestion was really good, here is our minimal configuration using Keycloak in discovery mode:

# Enable OIDC
OIDC_ENABLED=true
# Name your button (ignored in current 3.5.3 but fix is done in upcoming releases)
OIDC_DISPLAY_NAME=Login with MySSO
# Where to find your Keycloak OIDC server
OIDC_ISSUER=https://<keycloak_domain>/realms/<my_realm>
# Use discovery to determing all OIDC endpoints
OIDC_DISCOVERY=true
# Scope you want to obtain from OIDC server
OIDC_SCOPE=openid,profile,email
# Field to be used for populating user's @alias
OIDC_UID_FIELD=preferred_username
# Client ID of the client you configured for Mastodon in Keycloak
OIDC_CLIENT_ID=<keycloak_client_id>
# Client secret of the client you configured for Mastodon in Keycloak (in production, use secrets Docker secrets in our case)
OIDC_CLIENT_SECRET=<keycloak_client_secret>
# Where OIDC server should come back after authentication
OIDC_REDIRECT_URI=https://<mastodon_domain>/auth/auth/openid_connect/callback
# Assume emails are verified by the OIDC server
OIDC_SECURITY_ASSUME_EMAIL_IS_VERIFIED=true

So only difference is that we didn't have to add the OIDC_AUTH_ENDPOINT thanks to OIDC discovery.