[Bug]: SAML users without file access in 29.0.3rcX, 28.0.7rcX, 27.1.11rcX

[blizzz]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

The regression was introduced with adding a second scope in the scope-mechanism. The related PR is #43942

We have a LockdownManager and it has a logic that double checks whether file access exists in: https://github.com/nextcloud/server/blob/master/lib/private/Lockdown/LockdownManager.php#L61-L64

It's conditions are:

1. Either no scope is set
2. Or filesystem is set in the scope

In the login logic, when auth succeed without a password, we set the SCOPE_SKIP_PASSWORD_VALIDATION only.

A quick workaround is to set the filesystem access there as well.

Steps to reproduce

1. Login via user_saml
2. Go to Files, but see no Files
3. Trying to upload files fails

Expected behavior

Files are present and accessible

Installation method

None

Nextcloud Server version

master

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response