Load password from dbus to put into provider config

I have a provider, which wants a username/password to authenticate against a remote system.

Now the usual way of storing this information on my Ubuntu would be some app, which implements SecretService dbus API. Thus optimally I would like to store it in e.g. Gnome Keyring and access the value via dbus. Even if I could access the value via local-exec, I am not sure though how to pass around a secure value to Terraform.

The only/best way to make this work seems to be to implement a provider with a dbus_secretservice_login DataSource. Or am I missing something?