fail2ban service: improve ssh jail

[c0bw3b]

Motivation for this change

The default jail defined for sshd was blocking the port tcp/22 regardless of what is actually configured for the openssh daemon through config.services.openssh.ports

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[mention-bot]

@c0bw3b, thanks for your PR! By analyzing the history of the files in this pull request, we identified @edolstra, @lihop and @groxxda to be potential reviewers.

[nlewo]

@c0bw3b could you please rebase your commits (remove merges) ?
Otherwise, LGMT.
I tested with nixos-build-vms

{
  fail2ban = {pkgs, config, ...}:
    {
      services.openssh.enable = true;
      nixpkgs.system = "i686-linux";
      services.openssh.ports = [ 22  2222 ];
      services.fail2ban.enable = true;
    };
}

and it works fine.

[globin]

Squash-merged, thanks 👍

[c0bw3b]

Thanks @globin
Yes sorry about the remote-tracking commits... will avoid playing with Github Desktop on something intended to become a PR on Nixos from now on. :)