SDDM doesn’t log in if u2f is enabled

[vegaelle]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Enable U2F in configuration.nix and rebuild the system:

   hardware.u2f.enable = True;
   security.pam.u2f = {
     enable = true;
     control = "required";
     cue = true;
   };
   

2. Create a U2F token for your user with pamu2f -u <user> > /home/<user>/.config/Yubico/u2f_keys && chown -R <user> /home/<user>/.config/Yubico
3. Log in as <user> in SDDM. Type the password, plug in your U2F key, if your model has a physical button, click it when it blinks.

Expected behavior
Given that the login is valid, the desktop manager should start. Instead, SDDM seems to be waiting for something, doesn’t respond to anything. Setting the security.pam.u2f.control = "optional" allows to log in if the u2f key isn’t plugged in, but shows the same problem if it is. Even if the password is wrong, SDDM will hang when touching the U2F button.

Additional context
Add any other context about the problem here.

Notify maintainers
@abbradar @ttuegel

Metadata

 - system: `"x86_64-linux"`
 - host os: `Linux 5.4.45, NixOS, 20.03.2141.8b071be7512 (Markhor)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.6`
 - channels(root): `"home-manager-20.03, nixos-20.03.2141.8b071be7512, nixos-hardware, unstable-20.09pre228622.029a5de0839"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
# a list of nixos modules affected by the problem
module:

[flokli]

This seems to be an odering problem. Cross-linking for better visibility: #90640

[stale]

I marked this as stale due to inactivity. → More info