# Configuring Synapse to authenticate against an OpenID Connect provider

Synapse can be configured to use an OpenID Connect Provider (OP) for authentication, instead of its own local password database.

Any OP should work with Synapse, as long as it supports the authorization code flow. There are a few options for that:

- start a local OP. Synapse has been tested with Hydra and Dex. Note that for an OP to work, it should be served under a secure (HTTPS) origin. A certificate signed with a self-signed, locally trusted CA should work. In that case, start Synapse with a `SSL_CERT_FILE` environment variable set to the path of the CA.

- set up a SaaS OP, like Google, Auth0 or Okta. Synapse has been tested with Auth0 and Google.

It may also be possible to use other OAuth2 providers which provide the authorization code grant type, such as Github.

## Preparing Synapse

The OpenID integration in Synapse uses the `authlib` library, which must be installed as follows:

- The relevant libraries are included in the Docker images and Debian packages provided by `matrix.org` so no further action is needed.

- If you installed Synapse into a virtualenv, run `/path/to/env/bin/pip install matrix-synapse[oidc]` to install the necessary dependencies.

- For other installation mechanisms, see the documentation provided by the maintainer.

To enable the OpenID integration, you should then add a section to the `oidc_providers` setting in your configuration file (or uncomment one of the existing examples). See sample_config.yaml for some sample settings, as well as the text below for example configurations for specific providers.

## Sample configs

Here are a few configs for providers that should work with Synapse.

### Microsoft Azure Active Directory

Azure AD can act as an OpenID Connect Provider. Register a new application under App registrations in the Azure AD management console. The RedirectURI for your application should point to your matrix server: `[synapse public baseurl]/_synapse/client/oidc/callback`

Go to Certificates & secrets and register a new client secret. Make note of your Directory (tenant) ID as it will be used in the Azure links. Edit your Synapse config file and change the `oidc_config` section:

    oidc_providers:
      - idp_id: microsoft
        idp_name: Microsoft
        issuer: "https://login.microsoftonline.com/<tenant id>/v2.0"
        client_id: "<client id>"
        client_secret: "<client secret>"
        scopes: ["openid", "profile"]
        authorization_endpoint: "https://login.microsoftonline.com/<tenant id>/oauth2/v2.0/authorize"
        token_endpoint: "https://login.microsoftonline.com/<tenant id>/oauth2/v2.0/token"
        userinfo_endpoint: "https://graph.microsoft.com/oidc/userinfo"

        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username.split('@')[0] }}"
            display_name_template: "{{ user.name }}"

### Dex

Dex is a simple, open-source OpenID Connect Provider. Although it is designed to help building a full-blown provider with an external database, it can be configured with static passwords in a config file.

Follow the Getting Started guide to install Dex.

Edit `examples/config-dev.yaml` config file from the Dex repo to add a client:

    staticClients:
    - id: synapse
      secret: secret
      redirectURIs:
      - '[synapse public baseurl]/_synapse/client/oidc/callback'
      name: 'Synapse'

Run with `dex serve examples/config-dev.yaml`.

Synapse config:

    oidc_providers:
      - idp_id: dex
        idp_name: "My Dex server"
        skip_verification: true # This is needed as Dex is served on an insecure endpoint
        issuer: "http://127.0.0.1:5556/dex"
        client_id: "synapse"
        client_secret: "secret"
        scopes: ["openid", "profile"]
        user_mapping_provider:
          config:
            localpart_template: "{{ user.name }}"
            display_name_template: "{{ user.name|capitalize }}"

### Keycloak

Keycloak is an opensource IdP maintained by Red Hat.

Follow the Getting Started Guide to install Keycloak and set up a realm.

1. Click `Clients` in the sidebar and click `Create`

2. Fill in the fields as below:

Field | Value
--- | ---
Client ID | `synapse`
Client Protocol | `openid-connect`

3. Click `Save`
4. Fill in the fields as below:

Field | Value
--- | ---
Client ID | `synapse`
Enabled | `On`
Client Protocol | `openid-connect`
Access Type | `confidential`
Valid Redirect URIs | `[synapse public baseurl]/_synapse/client/oidc/callback`

5. Click `Save`
6. On the Credentials tab, update the fields:

Field | Value
--- | ---
Client Authenticator | `Client ID and Secret`

7. Click `Regenerate Secret`
8. Copy Secret

    oidc_providers:
      - idp_id: keycloak
        idp_name: "My KeyCloak server"
        issuer: "https://127.0.0.1:8443/auth/realms/{realm_name}"
        client_id: "synapse"
        client_secret: "copy secret generated from above"
        scopes: ["openid", "profile"]
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}"
            display_name_template: "{{ user.name }}"

### Auth0

Auth0 is a hosted SaaS IdP solution.

1. Create a regular web application for Synapse

2. Set the Allowed Callback URLs to `[synapse public baseurl]/_synapse/client/oidc/callback`

3. Add a rule to add the `preferred_username` claim.

   Code sample

       function addPersistenceAttribute(user, context, callback) {
         user.user_metadata = user.user_metadata || {};
         user.user_metadata.preferred_username = user.user_metadata.preferred_username || user.user_id;
         context.idToken.preferred_username = user.user_metadata.preferred_username;

         auth0.users.updateUserMetadata(user.user_id, user.user_metadata)
           .then(function(){
               callback(null, user, context);
           })
           .catch(function(err){
               callback(err);
           });
       }

Synapse config:

    oidc_providers:
      - idp_id: auth0
        idp_name: Auth0
        issuer: "https://your-tier.eu.auth0.com/" # TO BE FILLED
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        scopes: ["openid", "profile"]
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}"
            display_name_template: "{{ user.name }}"

### Authentik

Authentik is an open-source IdP solution.

1. Create a provider in Authentik, with type OAuth2/OpenID.
2. The parameters are:

- Client Type: Confidential
- JWT Algorithm: RS256
- Scopes: OpenID, Email and Profile
- RSA Key: Select any available key
- Redirect URIs: `[synapse public baseurl]/_synapse/client/oidc/callback`

3. Create an application for synapse in Authentik and link it to the provider.
4. Note the slug of your application, Client ID and Client Secret.

Note: RSA keys must be used for signing for Authentik, ECC keys do not work.

Synapse config:

    oidc_providers:
      - idp_id: authentik
        idp_name: authentik
        discover: true
        issuer: "https://your.authentik.example.org/application/o/your-app-slug/" # TO BE FILLED: domain and slug
        client_id: "your client id" # TO BE FILLED
        client_secret: "your client secret" # TO BE FILLED
        scopes:
          - "openid"
          - "profile"
          - "email"
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}"
            display_name_template: "{{ user.preferred_username|capitalize }}" # TO BE FILLED: If your users have names in Authentik and you want those in Synapse, this should be replaced with user.name|capitalize.

### LemonLDAP

LemonLDAP::NG is an open-source IdP solution.

1. Create an OpenID Connect Relying Parties in LemonLDAP::NG
2. The parameters are:

- Client ID under the basic menu of the new Relying Parties (`Options > Basic > Client ID`)
- Client secret (`Options > Basic > Client secret`)
- JWT Algorithm: RS256 within the security menu of the new Relying Parties (`Options > Security > ID Token signature algorithm` and `Options > Security > Access Token signature algorithm`)
- Scopes: OpenID, Email and Profile
- Allowed redirection addresses for login (`Options > Basic > Allowed redirection addresses for login` ) : `[synapse public baseurl]/_synapse/client/oidc/callback`

Synapse config:

    oidc_providers:
      - idp_id: lemonldap
        idp_name: lemonldap
        discover: true
        issuer: "https://auth.example.org/" # TO BE FILLED: replace with your domain
        client_id: "your client id" # TO BE FILLED
        client_secret: "your client secret" # TO BE FILLED
        scopes:
          - "openid"
          - "profile"
          - "email"
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}}"
            # TO BE FILLED: If your users have names in LemonLDAP::NG and you want those in Synapse, this should be replaced with user.name|capitalize or any valid filter.
            display_name_template: "{{ user.preferred_username|capitalize }}"

### GitHub

GitHub is a bit special as it is not an OpenID Connect compliant provider, but just a regular OAuth2 provider.

The `/user` API endpoint can be used to retrieve information on the authenticated user. As the Synapse login mechanism needs an attribute to uniquely identify users, and that endpoint does not return a `sub` property, an alternative `subject_claim` has to be set.

1. Create a new OAuth application: https://github.com/settings/applications/new.
2. Set the callback URL to `[synapse public baseurl]/_synapse/client/oidc/callback`.

Synapse config:

    oidc_providers:
      - idp_id: github
        idp_name: Github
        idp_brand: "github"  # optional: styling hint for clients
        discover: false
        issuer: "https://github.com/"
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        authorization_endpoint: "https://github.com/login/oauth/authorize"
        token_endpoint: "https://github.com/login/oauth/access_token"
        userinfo_endpoint: "https://api.github.com/user"
        scopes: ["read:user"]
        user_mapping_provider:
          config:
            subject_claim: "id"
            localpart_template: "{{ user.login }}"
            display_name_template: "{{ user.name }}"

### Google

Google is an OpenID certified authentication and authorisation provider.

1. Set up a project in the Google API Console (see https://developers.google.com/identity/protocols/oauth2/openid-connect#appsetup).
2. Add an "OAuth Client ID" for a Web Application under "Credentials".
3. Copy the Client ID and Client Secret, and add the following to your synapse config:

       oidc_providers:
         - idp_id: google
           idp_name: Google
           idp_brand: "google"  # optional: styling hint for clients
           issuer: "https://accounts.google.com/"
           client_id: "your-client-id" # TO BE FILLED
           client_secret: "your-client-secret" # TO BE FILLED
           scopes: ["openid", "profile"]
           user_mapping_provider:
             config:
               localpart_template: "{{ user.given_name|lower }}"
               display_name_template: "{{ user.name }}"

4. Back in the Google console, add this Authorized redirect URI: `[synapse public baseurl]/_synapse/client/oidc/callback`.

### Twitch

1. Setup a developer account on Twitch
2. Obtain the OAuth 2.0 credentials by creating an app
3. Add this OAuth Redirect URL: `[synapse public baseurl]/_synapse/client/oidc/callback`

Synapse config:

    oidc_providers:
      - idp_id: twitch
        idp_name: Twitch
        issuer: "https://id.twitch.tv/oauth2/"
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        client_auth_method: "client_secret_post"
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}"
            display_name_template: "{{ user.name }}"

### GitLab

1. Create a new application.
2. Add the `read_user` and `openid` scopes.
3. Add this Callback URL: `[synapse public baseurl]/_synapse/client/oidc/callback`

Synapse config:

    oidc_providers:
      - idp_id: gitlab
        idp_name: Gitlab
        idp_brand: "gitlab"  # optional: styling hint for clients
        issuer: "https://gitlab.com/"
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        client_auth_method: "client_secret_post"
        scopes: ["openid", "read_user"]
        user_profile_method: "userinfo_endpoint"
        user_mapping_provider:
          config:
            localpart_template: '{{ user.nickname }}'
            display_name_template: '{{ user.name }}'

### Facebook

0. You will need a Facebook developer account. You can register for one here.
1. On the apps page of the developer console, "Create App", and choose "Build Connected Experiences".
2. Once the app is created, add "Facebook Login" and choose "Web". You don't need to go through the whole form here.
3. In the left-hand menu, open "Products"/"Facebook Login"/"Settings".
   - Add `[synapse public baseurl]/_synapse/client/oidc/callback` as an OAuth Redirect URL.
4. In the left-hand menu, open "Settings/Basic". Here you can copy the "App ID" and "App Secret" for use below.

Synapse config:

      - idp_id: facebook
        idp_name: Facebook
        idp_brand: "facebook"  # optional: styling hint for clients
        discover: false
        issuer: "https://www.facebook.com"
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        scopes: ["openid", "email"]
        authorization_endpoint: "https://facebook.com/dialog/oauth"
        token_endpoint: "https://graph.facebook.com/v9.0/oauth/access_token"
        jwks_uri: "https://www.facebook.com/.well-known/oauth/openid/jwks/"
        user_mapping_provider:
          config:
            display_name_template: "{{ user.name }}"
            email_template: "{{ '{{ user.email }}' }}"

Relevant documents:

- Manually Build a Login Flow
- Using Facebook's Graph API
- Reference to the User endpoint

Facebook do have an OIDC discovery endpoint, but it has a `response_types_supported` which excludes "code" (which we rely on, and is even mentioned in their documentation), so we have to disable discovery and configure the URIs manually.

### Gitea

Gitea is, like Github, not an OpenID provider, but just an OAuth2 provider.

The `/user` API endpoint can be used to retrieve information on the authenticated user. As the Synapse login mechanism needs an attribute to uniquely identify users, and that endpoint does not return a `sub` property, an alternative `subject_claim` has to be set.

1. Create a new application.
2. Add this Callback URL: `[synapse public baseurl]/_synapse/client/oidc/callback`

Synapse config:

    oidc_providers:
      - idp_id: gitea
        idp_name: Gitea
        discover: false
        issuer: "https://your-gitea.com/"
        client_id: "your-client-id" # TO BE FILLED
        client_secret: "your-client-secret" # TO BE FILLED
        client_auth_method: client_secret_post
        scopes: [] # Gitea doesn't support Scopes
        authorization_endpoint: "https://your-gitea.com/login/oauth/authorize"
        token_endpoint: "https://your-gitea.com/login/oauth/access_token"
        userinfo_endpoint: "https://your-gitea.com/api/v1/user"
        user_mapping_provider:
          config:
            subject_claim: "id"
            localpart_template: "{{ user.login }}"
            display_name_template: "{{ user.full_name }}"

### XWiki

Install OpenID Connect Provider extension in your XWiki instance.

Synapse config:

    oidc_providers:
      - idp_id: xwiki
        idp_name: "XWiki"
        issuer: "https://myxwikihost/xwiki/oidc/"
        client_id: "your-client-id" # TO BE FILLED
        client_auth_method: none
        scopes: ["openid", "profile"]
        user_profile_method: "userinfo_endpoint"
        user_mapping_provider:
          config:
            localpart_template: "{{ user.preferred_username }}"
            display_name_template: "{{ user.name }}"

### Apple

Configuring "Sign in with Apple" (SiWA) requires an Apple Developer account.

You will need to create a new "Services ID" for SiWA, and create and download a private key with "SiWA" enabled.

As well as the private key file, you will need:

- Client ID: the "identifier" you gave the "Services ID"
- Team ID: a 10-character ID associated with your developer account.
- Key ID: the 10-character identifier for the key.

https://help.apple.com/developer-account/?lang=en#/dev77c875b7e has more documentation on setting up SiWA.

The synapse config will look like this:

      - idp_id: apple
        idp_name: Apple
        issuer: "https://appleid.apple.com"
        client_id: "your-client-id" # Set to the "identifier" for your "ServicesID"
        client_auth_method: "client_secret_post"
        client_secret_jwt_key:
          key_file: "/path/to/AuthKey_KEYIDCODE.p8"  # point to your key file
          jwt_header:
            alg: ES256
            kid: "KEYIDCODE"   # Set to the 10-char Key ID
          jwt_payload:
            iss: TEAMIDCODE    # Set to the 10-char Team ID
        scopes: ["name", "email", "openid"]
        authorization_endpoint: https://appleid.apple.com/auth/authorize?response_mode=form_post
        user_mapping_provider:
          config:
            email_template: "{{ user.email }}"

### Django OAuth Toolkit

django-oauth-toolkit is a Django application providing out of the box all the endpoints, data and logic needed to add OAuth2 capabilities to your Django projects. It supports OpenID Connect too.

Configuration on Django's side:

1. Add an application: https://example.com/admin/oauth2_provider/application/add/ and choose parameters like this:

- `Redirect uris`: https://synapse.example.com/_synapse/client/oidc/callback
- `Client type`: `Confidential`
- `Authorization grant type`: `Authorization code`
- `Algorithm`: `HMAC with SHA-2 256`

2. You can customize the claims Django gives to synapse (optional):

   Code sample

       class CustomOAuth2Validator(OAuth2Validator):

           def get_additional_claims(self, request):
               return {
                   "sub": request.user.email,
                   "email": request.user.email,
                   "first_name": request.user.first_name,
                   "last_name": request.user.last_name,
               }

Your synapse config is then:

    oidc_providers:
      - idp_id: django_example
        idp_name: "Django Example"
        issuer: "https://example.com/o/"
        client_id: "your-client-id"  # CHANGE ME
        client_secret: "your-client-secret"  # CHANGE ME
        scopes: ["openid"]
        user_profile_method: "userinfo_endpoint"  # needed because oauth-toolkit does not include user information in the authorization response
        user_mapping_provider:
          config:
            localpart_template: "{{ user.email.split('@')[0] }}"
            display_name_template: "{{ user.first_name }} {{ user.last_name }}"
            email_template: "{{ user.email }}"