klausbetz/apple-identity-provider-keycloak

An extension for Keycloak, that enables web-based sign in with Apple and token exchange

Apple Identity Provider for Keycloak 🍎

This repository represents an extension for Keycloak, which enables Sign in with Apple for web-based applications and native application (via token-exchange).

Apple vs. the rest of the world

Since Apple does not comply 100% to the existing OpenID Connect standard, some customizations are necessary in order to make the Apple way compatible to Keycloak. Differences are as follows:

• If scopes were requested, Apple sends the TokenResponse as a POST request
• There's no userinfo endpoint. email, firstName and lastName are transmitted only the first time the user signs in with Apple.
• The /token-request must contain a client-secret (JWT) which is signed using a specific private key (.p8 file).

Installation

1. Make sure you have a copy of the latest JAR of this provider package or include it as a Maven dependency .
2. Deploy the JAR file to keycloak (by placing it in /opt/keycloak/providers inside your docker container; alternatively see this guide)
3. Keycloak might need a restart (or a fresh container when using docker)

See a Dockerfile example.

Compatibility

Since this package implements internal Keycloak SPIs, there's a chance this extension breaks with a new major version of Keycloak.
See compatibility list below to find the version that suits your Keycloak version.

Keycloak Version	Extension Version
< 17.0.0	Not tested. Use at your own risk.
17.0.0 <= 19.0.3	1.2.0
20.0.0 <= 20.0.5 ℹ️	1.3.0 <= 1.4.1
21.0.0 <= 21.0.2 ℹ️	1.5.0
21.1.0 <= 21.1.2 ℹ️	1.6.0
22.0.0 < 23.0.0	1.7.0 <= 1.8.0
>= 23.0.0	>= 1.9.0

ℹ️ In Keycloak v21.X.Y this extension cannot be used effectively, since the additional properties such as Team ID, Key ID and so on are not displayed in the Admin UI.
However, you can still use this extension with Keycloak v21.X.Y when you use some sort of external configuration tools like terraform or keycloak-config-cli where you do not rely on Keycloak's UI.

ℹ️ For Keycloak v19 and v20 you have to switch to the old Admin UI to use this extension (see this paper Keycloak 19.0.0 release)

Configuration

Log into your Keycloak admin console and add Apple as new Identity Provider and get comfortable with the configuration options:

Option	Description
Client ID (= Service ID)	Your Service ID from your Apple Developer Account.
Client Secret	(Ignored) Just use a dummy value.
Team ID	Your Team ID obtained from your Apple Developer Account.
Key ID	A key identifier obtained from your Apple Developer Account.
p8 Key	Raw content of p8 key file you get from your Apple Developer Account.
Default Scopes	Scopes to request from Apple (for web-based logins). Defaults to name%20email

🙋 If you are unsure where you get these values from your Apple Developer Account you may want to check out this guide.

⚠️ Make sure to add the keycloak broker-URL (https://<keycloak-url>/realms/<realm>/broker/apple/endpoint) to your valid redirect URLs in your Apple Developer Account.

Token exchange

Token exchange can be used to trade Apple tokens for Keycloak access- and refresh-tokens.
This flow is mostly interesting for native applications like iOS apps, to provide native login options.

1. Using Apple ID-Token (recommended)

You want to use the /token endpoint of your realm to exchange an Apple ID-Token for Keycloak tokens.
<keycloak server url>/realms/<realm>/protocol/openid-connect/token
application/x-www-form-urlencoded

Parameter	Description
client_id	the client id of your Keycloak client
grant_type	urn:ietf:params:oauth:grant-type:token-exchange
subject_token	ID-Token from Apple
subject_issuer	apple (the name of the social provider in keycloak)
subject_token_type	urn:ietf:params:oauth:token-type:id_token
user_profile	{ "name": { "firstName": string, "lastName": string }, "email": string } optional. The JSON string that Apple sends on the first login (only required for the first login if you want to store the user's name)

2. Using Apple authorization_code

Details

Looking at 3 from the image above, you want to use the /token endpoint of your realm to exchange an Apple authorizationCode for Keycloak tokens.
<keycloak server url>/realms/<realm>/protocol/openid-connect/token
application/x-www-form-urlencoded

Parameter	Description
client_id	the client id of your Keycloak client
grant_type	urn:ietf:params:oauth:grant-type:token-exchange
subject_token	authorizationCode from Apple
subject_issuer	apple (the name of the social provider in keycloak)
user_profile	{ "name": { "firstName": string, "lastName": string }, "email": string } optional. The JSON string that Apple sends on the first login (only required for the first login if you want to store the user's name)
app_identifier	In case the configured Service ID doesn't match the bundle-identifier of the native iOS app, this parameter can be used, so that Service ID is ignored and app_identifier is used instead (Apple might throw a client_id mismatch exception if not provided). If the Service ID already matches your bundle-identifier you can omit this parameter.