I've just installed Nextcloud 11 into my environment, and am working on integrating it from an authentication perspective. I've already configured it to point to our corporate Active Directory tree and can successfully log in with AD user accounts. In addition to that, I'm trying to integrate it into the Apereo CAS install that I have going for Single Sign On. It seems like the easiest way to do this is using the user_saml module, configuring it for the "Environment" authentication (using the REMOTE_USER variable), and then configuring mod_auth_cas to do the authentication. I've used mod_auth_cas with several other apps (Cacti, Foreman, PHPIPAM, MediaWiki), so I know that it works correctly, but I'm struggling to get NextCloud to authenticate through SSO.
The behavior I'm seeing is that, when I go to the NextCloud page, I get redirected to the SSO login, as expected. I enter credentials, get logged in to SSO, and then get redirected back to the NextCloud login page where I'm prompted for a username and password instead of being transparently logged in via SSO.
I've configured user_saml as described in the admin manual under the "Configuring environment based authentication" section of the "Configure Single Sign On" page in the admin manual, using the mod_auth_kerb example, but substituting in mod_auth_cas, instead. Basically, my config is:
- AD configured in NextCloud for LDAP authentication
- user_saml enabled, selected environment authentication.
- Entered "REMOTE_USER" in the text field for the "attribute" to use for login.
- Checked the box that requires user to be present in some other database (local or LDAP) for login to succeed.
So, the question is: what am I missing?! I spent a couple of hours yesterday trying various configurations yesterday to get this to work and could never quite nail it down. My suspicion is that SSO is returning the sAMAccountName attribute for the username, whereas NextCloud is configured to use a calculated or retrieved UUID/GUID from LDAP for the internal username, but I'm not 100% certain about that. Anyone have any success getting this working??