nixos/howdy: init

[fufexan]

Description of changes

Adds Howdy as a service.

TODO:

• make sure it can add/recognize/remove facial models.
• add optional linux-enable-ir-emitter service needed for some IR cameras.
• get it working properly with PAM.
• get the GTK version running (may be out of scope for now).
• Resolve PAM comment by @Majiir .

Fixes #76928

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

closes #344024

[Atemu]

I don't have the HW to test this.

[doronbehar]

Sorry for more comment that could have been given earlier.

[D3vil0p3r]

Hello guys. Please if you plan to apply commits can you please switch the PR to draft state? Otherwise our mailboxes will be filled by a lot of notification emails. Thanks

[doronbehar]

Last comments so it seems!

[doronbehar]

One last review comment indeed!

[AkechiShiro]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 216245
Commit: 83363921d792005dd50ba957d9f8c5eea6271928

---

x86_64-linux

⏩ 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

✅ 1 test built:

• nixosTests.simple

✅ 7 packages built:

• howdy
• linux-enable-ir-emitter
• tests.devShellTools.nixos
• tests.testers.lycheeLinkCheck.network
• tests.testers.nixosTest-example
• tests.testers.runNixOSTest-example (tests.testers.runNixOSTest-extendNixOS)
• tests.trivial-builders.references

[doronbehar]

OK great. I think you can squash the commits as discussed before. We are still waiting for a reply by @Majiir in #216245 (comment) , or perhaps somebody else that is confident enough with PAM in NixOS. Since that thread is hard to find due to the large amount of commits here, I wrote it in the top level comment.

[Majiir]

PAM changes look good to me.

I suggest testing to double-check that the required control behaves as expected with Howdy. If a failure with Howdy interacts poorly with password prompts, you might need to use requisite. Howdy itself ships with a rule that uses [success=end default=ignore], which is pretty much sufficient - but that seems to contradict their own guidance to not use Howdy as the only auth method.

I can't make a good recommendation for the default here because I don't use face recognition and I don't know what users expect. But I'm happy to advise on any PAM changes in case you need to reorder the rule or anything.

[fufexan]

I can't make a good recommendation for the default here because I don't use face recognition and I don't know what users expect. But I'm happy to advise on any PAM changes in case you need to reorder the rule or anything.

We might need to in the future when linux-enable-ir-emitter ships v7.0.0. https://github.com/emixampp/linux-enable-ir-emitter?tab=readme-ov-file#integration-with-howdy

[fufexan]

I suggest testing to double-check that the required control behaves as expected with Howdy. If a failure with Howdy interacts poorly with password prompts, you might need to use requisite.

I've tested this with my lock screen:

Control required or requisite (behaves the same):
howdy fail without password: PAM fail
howdy fail with password: PAM fail
howdy pass without password: PAM fail
howdy pass with password: PAM success

Looks like it behaves like 2FA with these two control flags. IMO it's a good default, though it might confuse users. I'll make a note of it in the howdy module.

[doronbehar]

@fufexan please squash the commits as we discussed earlier. Note also the target branch of the PR has changed.

[doronbehar]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 216245
Commit: beea11b99e0ee7e9891f2273743e1a07f84156a5

---

x86_64-linux

⏩ 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

✅ 1 test built:

• nixosTests.simple

✅ 7 packages built:

• howdy
• linux-enable-ir-emitter
• tests.devShellTools.nixos
• tests.testers.lycheeLinkCheck.network
• tests.testers.nixosTest-example
• tests.testers.runNixOSTest-example (tests.testers.runNixOSTest-extendNixOS)
• tests.trivial-builders.references

---

aarch64-linux

⏩ 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

❌ 6 packages failed to build:

• nixosTests.simple
• tests.devShellTools.nixos
• tests.testers.lycheeLinkCheck.network
• tests.testers.nixosTest-example
• tests.testers.runNixOSTest-example (tests.testers.runNixOSTest-extendNixOS)
• tests.trivial-builders.references

---

x86_64-darwin

❌ 2 packages failed to build:

• darwin.linux-builder (darwin.linux-builder-x86_64)
• nixosTests.simple

---

aarch64-darwin

❌ 2 packages failed to build:

• darwin.linux-builder
• nixosTests.simple

✅ 1 package built:

• darwin.linux-builder-x86_64

[doronbehar]

The test failures seem completely unrelated. I wonder why nixpkgs-review decided to build them...

[Xyz00777]

sorry for the ping, but woop woop <3
thanks for all the persons that helped to bring this to the current state ^^

[VuiMuich]

Just a small heads-up: for me it was necessary to remove the face-data I created during testing, and re-add otherwise authentication failed despite the password being correct.

[Xyz00777]

heyho, i have a howdy pam behaviour i didnt had before i switched to the nixos-unstable version from your fork.
Im currently trying to disable howdy for the loginscreen, because i see no advance beside it takes longer.
i already created:

security.pam.services.login = {
      enable = true;
      rules = {
        auth = {
          # was recommended by the arch wiki to continue to allow passwd auth in UIs.
          pam-unix = {
            enable = true;
            control = "sufficient";
            modulePath = "${pkgs.linux-pam}/lib/security/pam_unix.so";
            settings = {
              "try_first_pass" = true;
              "likeauth" = true;
              "nullok" = true;
            };
            order = config.security.pam.services.su.rules.auth.unix.order - 90;
          };

          pam-howdy = {
            enable = false;
            control = "sufficient";
            modulePath = "${pkgs.howdy}/lib/security/pam_howdy.so";
            order = config.security.pam.services.su.rules.auth.unix.order - 110;
          };
        };
      };
    };

but its not turning off. I also had the problem at some point that i was not able to login at all with an pam failure, but im not able to rebuild that error currently... Oh and the autounlock of my kdewallet is also not working anymore :/
edit:
got kdewallet to autounlock again with adding in the same code snippet pam-kwallet with control "optional". But still not able to find out how to deactivate it for my kde sddm login screen. also already tried out to use pam sddm to disable it, and did also not work :/
security.pam.services.sddm.howdy.enable = false;

[mettavi]

Try:

security.pam.services.sddm.howdy.enable = false;
security.pam.services.login.howdy.enable = false;

[endeavour]

Trying to use this but greetd requires both a password and the facial recognition to login. I don't really need this level of security on my home desktop. I have 'security.pam.services.greetyd.howdy.control = "sufficient"' - am I missing something?

[fufexan]

You have a typo. should be

- security.pam.services.greetyd.howdy.control = "sufficient"
+ security.pam.services.greetd.howdy.control = "sufficient"

[endeavour]

You have a typo. should be

- security.pam.services.greetyd.howdy.control = "sufficient"
+ security.pam.services.greetd.howdy.control = "sufficient"

Ah thanks, though I must have been half asleep when I wrote this. I realised I was actually testing it against the noctalia lock screen rather than greetd. Not quite sure how to get this configured.