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Synapse Section: Delegated Auth


DESCRIPTION

All settings configured via the UI in this section will be saved to your deployment.yml, with the contents of secrets being saved to secrets.yml. You will find specific configuration examples in each section.

Config Example
  • deployment.yml 
    metadata:
annotations:
  ui.element.io/layer: |
    components:
      synapse:
spec:
  components:
    synapse:
  • secrets.yml 
    kind: Secret
metadata:
  name: synapse
  namespace: element-onprem
data:

By default, if you do not change any settings on this page, defaults will be added to your configuration file/s (see example below).

Config Example
  • deployment.yml 
    metadata:
  annotations:
    ui.element.io/layer: |
      components:

spec:
  components:
  • secrets.yml 
    apiVersion: v1
kind: Secret
metadata:

data:

At present, we support delegating the authentication of users to the following provider interfaces:

  • LDAP
  • SAML
  • OIDC

When enabling Delegated Auth, you can still allow local users managed by Element to connect to the instance

Screenshot 2023-05-04 at 09.23.54.png

When Allow Local Users Login is Enabled, you can both connect to your instance using your IDP and the local database.

Screenshot 2023-05-04 at 14.30.04.png

Different options are offered by the installer and you can combine two or more options on the same instance like enabling SAML and OIDC delegated authentication.

See the below relevant sections to your environment for specifics on getting configured.

LDAP on Windows AD

  • Base.
    The distinguished name of the root level Org Unit in your LDAP directory.
    • The distinguished name can be displayed by selecting View / Advanced Features in the Active Directory console and then, right-clicking on the object, selecting Properties / Attributes Editor.
  • Bind DN.
    The distinguished name of the LDAP account with read access.
  • Filter.
    A LDAP filter to filter out objects under the LDAP Base DN.
  • URI.
    The URI of your LDAP server ldap://dc.example.com.
    • This is often your Domain Controller, can also pass in ldaps:// for SSL connectivity.
    • The following are the typical ports for Windows AD LDAP servers:
      • ldap://ServerName:389
      • ldaps://ServerName:636
  • LDAP Bind Password.
    The password of the AD account with read access.
  • LDAP Attributes.
    • Mail.
      mail
    • Name.
      cn
    • UID.
      sAMAccountName

OpenID on Microsoft Azure

Before configuring within the installer, you have to configure Microsoft Azure Active Directory.

Set up Microsoft Azure Active Directory

  • You need to create an App registration.
  • You have to select Redirect URI (optional) and set it to the following, where matrix is the subdomain of Synapse and example.com is your base domain as configured on the Domains section: 
    https://matrix.example.com/_synapse/client/oidc/callback

Screenshot 2023-05-03 at 16.30.06.png

For the bridge to be able to operate correctly, navigate to API permissions, add Microsoft Graph APIs, choose Delegated Permissions and add:

  • openid
  • profile
  • email

Remember to grant the admin consent for those.

To setup the installer, you'll need:

  • The Application (client) ID
  • The Directory (tenant) ID
  • A secret generated from Certificates & Secrets on the app.

Configure the installer

  • IdP Name.
    A user-facing name for this identity provider, which is used to offer the user a choice of login mechanisms in the Element UI.
  • IdP ID.
    A string identifying your identity provider in your configuration, this will be auto-generated for you (but can be changed).
  • IdP Brand.
    An optional brand for this identity provider, allowing clients to style the login flow according to the identity provider in question.
  • Issuer.
    The OIDC issuer. Used to validate tokens and (if discovery is enabled) to discover the provider's endpoints. Use https://login.microsoftonline.com/DIRECTORY_TENNANT_ID/v2.0 replacing DIRECTORY_TENNANT_ID.
  • Client Auth Method.
    Auth method to use when exchanging the token. Set it to Client Secret Post or any method supported by your IdP.
  • Client ID.
    Set this to your Application (client) ID.
  • Client Secret.
    Set this to the secret value defined under "Certificates and secrets".
  • Scopes.
    By default openid, profile and email are added, you shouldn't need to modify these.
  • User Mapping Provider.
    Configuration for how attributes returned from a OIDC provider are mapped onto a matrix user.
    • Localpart Template.
      Jinja2 template for the localpart of the MXID.
      Set it to {{ user.preferred_username.split('@')[0] }}.
    • Display Name Template.
      Jinja2 template for the display name to set on first login.
      If unset, no display name will be set. Set it to {{ user.name }}.
  • Discover.
    Enable / Disable the use of the OIDC discovery mechanism to discover endpoints.
  • Backchannel Logout Enabled.
    Synapse supports receiving OpenID Connect Back-Channel Logout notifications. This lets the OpenID Connect Provider notify Synapse when a user logs out, so that Synapse can end that user session. This property has to bet set to https://matrix.example.com/_synapse/client/oidc/backchannel_logoutin your identity provider, where matrix is the subdomain of Synapse and example.com is your base domain as configured on the Domains section.

OpenID on Microsoft AD FS

Install Microsoft AD FS

Before starting the installation, make sure:

  • your Windows computer name is correct since you won't be able to change it after having installed AD FS
  • you configured your server with a static IP address
  • your server joined a domain and your domain is defined under Server Manager > Local server
  • you can resolve your server FQDN like computername.my-domain.com

You can find a checklist here.

Steps to follow:

  • Install AD CS (Certificate Server) to issue valid certificates for AD FS. AD CS provides a platform for issuing and managing public key infrastructure [PKI] certificates.
  • Install AD FS (Federation Server)
Install AD CS

You need to install the AD CS Server Role.

Obtain and Configure an SSL Certificate for AD FS

Before installing AD FS, you are required to generate a certificate for your federation service. The SSL certificate is used for securing communications between federation servers and clients.

  • Follow this guide.
  • Additionally, this guide provides more details on how to create a certificate template.
Install AD FS

You need to install the AD FS Role Service.

Configure the federation service

AD FS is installed but not configured.

  • Click on Configure the federation service on this server under Post-deployment configuration in the Server Manager.
  • Ensure Create the first federation server in a federation server farm and is selected

Screenshot 2023-06-22 at 15.55.57.png

  • Click Next

Screenshot 2023-06-22 at 15.57.41.png

  • Select the SSL Certificate and set a Federation Service Display Name

Screenshot 2023-06-22 at 15.59.27.png

  • On the Specify Service Account page, you can either Create a Group Managed Service Account (gMSA) or Specify an existing Service or gMSA Account

Screenshot 2023-06-22 at 16.04.13.png

  • Choose your database

Screenshot 2023-06-22 at 16.05.50.png

  • Review Options , check prerequisites are completed and click on Configure
  • Restart the server
Add AD FS as an OpenID Connect identity provider

To enable sign-in for users with an AD FS account, create an Application Group in your AD FS.
To create an Application Group, follow theses steps:

  • In Server Manager, select Tools, and then select AD FS Management
  • In AD FS Management, right-click on Application Groups and select Add Application Group
  • On the Application Group Wizard Welcome screen
    • Enter the Name of your application
    • Under Standalone applications section, select Server application and click Next

Screenshot 2023-06-22 at 16.39.52.png

  • Enter https://<matrix domain>/_synapse/client/oidc/callback in Redirect URI: field, click Add, save the Client Identifier somewhere, you will need it when setting up Element and click Next (e.g. https://matrix.domain.com/_synapse/client/oidc/callback)

Screenshot 2023-06-22 at 16.45.44.png

  • Select Generate a shared secret checkbox and make a note of the generated Secret and press Next (Secret needs to be added in the Element Installer GUI in a later step)
  • Right click on the created Application Group and select `Properties``

Screenshot 2023-06-22 at 16.56.40.png

  • Select Add application... button.
  • Select Web API
  • In the Identifier field, type in the client_id you saved before and click Next

Screenshot 2023-06-23 at 09.48.07.png

  • Select Permit everyone and click Next
  • Under Permitted scopes: select openid and profile and click Next

Screenshot 2023-06-23 at 09.51.06.png

  • On Summary page, click `Next``
  • Click Close and then OK
Export Domain Trusted Root Certificate
  • Run mmc.exe
  • Add the Certificates snap-in
    • File/Add snap-in for Certificates, Computer account
  • Under Trusted Root Certification Authorities/Certificates, select your DC cert
  • Right click and select All Tasks/Export... and export as Base-64 encoded X 509 (.CER)
  • Copy file to local machine

Configure the installer

Add an OIDC provider in the 'Synapse' configuration after enabling Delegated Auth and set the following fields in the installer:

  • Allow Existing Users: if checked, it allows a user logging in via OIDC to match a pre-existing account instead of failing. This could be used if switching from password logins to OIDC.
  • Authorization Endpoint: the oauth2 authorization endpoint. Required if provider discovery is disabled.

    https://login.microsoftonline.com/<Directory (tenant) ID>/oauth2/v2.0/authorize

  • Backchannel Logout Enabled: Synapse supports receiving OpenID Connect Back-Channel Logout notifications. This lets the OpenID Connect Provider notify Synapse when a user logs out, so that Synapse can end that user session.
  • Client Auth Method: auth method to use when exchanging the token. Set it to Client Secret Basic or any method supported by your Idp
  • Client ID: the Client ID you saved before
  • Discover: enable/disable the use of the OIDC discovery mechanism to discover endpoints
  • Idp Brand: an optional brand for this identity provider, allowing clients to style the login flow according to the identity provider in question
  • Idp ID: a string identifying your identity provider in your configuration
  • Idp Name: A user-facing name for this identity provider, which is used to offer the user a choice of login mechanisms in the Element UI. In the screenshot bellow, Idp Name is set to Azure AD

Screenshot 2023-05-04 at 10.45.23.png

  • Issuer: the OIDC issuer. Used to validate tokens and (if discovery is enabled) to discover the provider's endpoints https://<your-adfs.domain.com>/adfs/
  • Token Endpoint: the oauth2 authorization endpoint. Required if provider discovery is disabled.
  • Client Secret: your client secret you saved before.
  • Scopes: add every scope on a different line
    • The openid scope is required which translates to the Sign you in permission in the consent UI
    • You might also include other scopes in this request for requesting consent.

Screenshot 2023-05-03 at 17.27.00.png

  • User Mapping Provider: Configuration for how attributes returned from a OIDC provider are mapped onto a matrix user.
    • Localpart Template: Jinja2 template for the localpart of the MXID. Set it to {{ user.upn.split('@')[0] }} for AD FS

Other configurations are documented here.

SAML on Microsoft Azure

Before setting up the installer, you have to configure Microsoft Entra ID.

Set up Microsoft Entra ID

With an account with enough rights, go to : Enterprise Applications

  1. Click on New Application
  2. Click on Create your own application on the top left corner
  3. Choose a name for it, and select Integrate any other application you don't find in the gallery
  4. Click on "Create"
  5. Select Set up single sign on
  6. Select SAML
  7. Edit on Basic SAML Configuration
  8. In Identifier , add the following URL : https://synapse_fqdn/_synapse/client/saml2/metadata.xml
  9. Remove the default URL
  10. In Reply URL , add the following URL : https://synapse_fqdn/_synapse/client/saml2/authn_response
  11. Click on Save

  1. Make a note of the App Federation Metadata Url under SAML Certificates as this will be required in a later step.
  2. Edit on Attributes & Claims
  3. Remove all defaults for additional claims
  4. Click on Add new claim to add the following (suggested) claims (the UID will be used as the MXID):
    • Name: uid , Transformation : ExtractMailPrefix , Parameter 1 : user.userprincipalname
    • Name: email , Source attribute : user.mail
    • Name: displayName , Source attribute : user.displayname
  5. Click on Save

  1. In the application overview screen select Users and Groups and add groups and users which may have access to element

Configure the installer

Add a SAML provider in the 'Synapse' configuration after enabling Delegated Auth and set the following (suggested) fields in the installer:

  • Allow Unknown Attributes.
    Checked
  • Attribute Map.
    Select URN:Oasis:Names:TC:SAML:2.0:Attrname Format:Basic as the Identifier
  • Mapping.
    Set the following mappings:
    • From: Primary Email To: email
    • From: First Name To: firstname
    • From: Last Name To: lastname
  • Entity.
    • Description.
    • Entity ID. (From Azure)
    • Name.
  • User Mapping Provider.
    Set the following:
    • MXID Mapping: Dotreplace
    • MXID Source Attribute: uid
  • Metadata URL.
    Add the App Federation Metadata URL from Azure.

Troubleshooting

Redirection loop on SSO

Synapse needs to have the X-Forwarded-For and X-Forwarded-Proto headers set by the reverse proxy doing the TLS termination. If you are using a Kubernetes installation with your own reverse proxy terminating TLS, please make sure that the appropriate headers are set.

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