SMB external storage ignores Kerberos authentication and attempts BasicAuth

⚠️ 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

Using external storage over SMB produce BasicAuth errors even when kerberos-ticket (apache-mode) authentification is selected.

Steps to reproduce

1. Install nextcloud with apache and kerberos authentification
2. configure LDAP
3. try to add external storage over SMB with kerberos ticket in apache-mode

Expected behavior

All users with rights can use external storage

Nextcloud Server version

32

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MariaDB

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

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

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

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

 Exception Icewind\SMB\BasicAuth::__construct(): Argument #3 ($password) must be of type string, null given, called in /var/www/html/nextcloud/apps/files_external/lib/Lib/Backend/SMB.php on line 106 in file '/var/www/html/nextcloud/3rdparty/icewind/smb/src/BasicAuth.php' line 17

    /var/www/html/nextcloud/lib/private/AppFramework/App.phpZeile 153

    OC\AppFramework\Http\Dispatcher->dispatch()

    /var/www/html/nextcloud/lib/private/Route/Router.phpZeile 321

    OC\AppFramework\App::main()

    /var/www/html/nextcloud/lib/base.phpZeile 1061

    OC\Route\Router->match()

    /var/www/html/nextcloud/index.phpZeile 25

    OC::handleRequest()

Verursacht von TypeError Icewind\SMB\BasicAuth::__construct(): Argument #3 ($password) must be of type string, null given, called in /var/www/html/nextcloud/apps/files_external/lib/Lib/Backend/SMB.php on line 106

Start in apps/files_external/lib/Lib/Backend/SMB.php around line 106 and inspect how the Kerberos ticket/apache-mode selection reaches Icewind\SMB\BasicAuth in 3rdparty/icewind/smb/src/BasicAuth.php. Reproduce the SMB external-storage setup with Apache Kerberos authentication and verify that Kerberos mode no longer attempts BasicAuth with a null password.