Rocket.Chat SaaS
Keycloak
https://www.keycloak.org/ is another popular open-source IdP that you can use in connection with Rocket.Chat.

Prerequisites

Keycloak:
  • Decide/set up a realm you want to use, e.g. master. The realm will be referenced by the placeholder <realm>.

Setting up Rocketchat

Go to the SAML settings in Rocketchat administration:
  • Decide the keycloak server "nickname" - e.g. keycloak.
  • For the custom entry point and IDP SLO Redirect URL, go for https://sso.example.com/auth/realms/<realm>/protocol/saml
  • Note the Custom Certificate - this is the Keycloak's realm certificate. Check out the realm settings, examine the Keys tab, and get the RSA Certificate and paste it to the field. Don't include the -----BEGIN/END CERTIFICATE----- headers/footers.
  • Generate the Public Certificate and Private Key if needed, or leave them as they are if they are present.

Setting up Keycloak

Go to https://r.example.com/_saml/metadata/keycloak - you should get an XML file. Save the raw file to your disk. Go to keycloak and open the "Add Client" dialogue. Select the SAML protocol, and import the XML file from the previous step. You will be redirected to a partially pre-filled client setting page. The client ID referenced by Keycloak should be the same as the metadata URL.
Create client, and now revisit its settings:
  • Check out Valid Redirect URIs - make sure that it is set to https://r.example.com/_saml/validate/keycloak.
  • Set the Name ID Format to email.
  • Go to the SAML Keys tab, and make sure that the public key (certificate) is the same as the Rocketchat's public key. Note that the -----BEGIN/END CERTIFICATE----- header/footer is not supposed to be part of the Keycloak's public key view, but the rest should be the same. If they are not the same, save the Rocketchat public key one into a text file, and import it from Keycloak - use the import PEM functionality.
  • Go to the Mappers tab, and create mappers for the required data that Rocketchat expects. You shouldn't need email or username, but you probably need cn.
    Click Create, and choose the type User Property and set the SAML Attribute NameFormat to basic. For the first name, set Name and Property to firstName, and SAML Attribute name to cn.

Troubleshooting

You should be done by now. However, you may run into some problems for various reasons:
  • Q: I keep getting the Unable to validate response url: Error: Status is: urn:oasis:names:tc:SAML:2.0:status:Responder error.
  • A: Make sure that the respective Keycloak user has an e-mail address. This may not be the case e.g. for Keycloak admin.
  • Q: How do I generate a certificate pair?
  • A: Try openssl req -newkey rsa:3072 -new -x509 -days 3652 -nodes -out saml.crt -keyout saml.pem. Then, just copy file contents to the respective fields.