nix-files/modules/ssh.nix

94 lines
2.9 KiB
Nix

{ config, lib, ... }:
with lib;
let
key = types.submodule ({ name, config, ...}: {
options = {
typedPubkey = mkOption {
type = types.str;
description = ''
the pubkey with type attached.
e.g. "ssh-ed25519 <base64>"
'';
};
# type = mkOption {
# type = types.str;
# description = ''
# the type of the key, e.g. "id_ed25519"
# '';
# };
host = mkOption {
type = types.str;
description = ''
the hostname of a key
'';
};
user = mkOption {
type = types.str;
description = ''
the username of a key
'';
};
asUserKey = mkOption {
type = types.str;
description = ''
append the "user@host" value to the pubkey to make it usable for ~/.ssh/id_<x>.pub or authorized_keys
'';
};
asHostKey = mkOption {
type = types.str;
description = ''
prepend the "host" value to the pubkey to make it usable for ~/.ssh/known_hosts
'';
};
};
config = rec {
user = head (lib.splitString "@" name);
host = last (lib.splitString "@" name);
asUserKey = "${config.typedPubkey} ${name}";
asHostKey = "${host} ${config.typedPubkey}";
};
});
coercedToKey = types.coercedTo types.str (typedPubkey: {
inherit typedPubkey;
}) key;
in
{
options = {
sane.ssh.pubkeys = mkOption {
type = types.attrsOf coercedToKey;
default = {};
description = ''
mapping from "user@host" to pubkey.
'';
};
};
config = {
# persist the host key.
# actually DON'T do it this way. else we compete with the /etc activation script and it triggers warnings on deploys.
# sane.persist.sys.byStore.plaintext = [ "/etc/ssh/host_keys" ];
# N.B.: use the plaintext `backing` dir instead of proper persistence, because this needs to be available
# during activation time (see /etc/machine-id and setupSecretsForUsers activation script).
# TODO: this should go in the same dir as `/var/log`, then. i.e. `stores.initrd` (but rename to `stores.early`).
environment.etc."ssh/host_keys" = let
plaintextBacking = config.sane.fs."${config.sane.persist.stores.plaintext.origin}".mount.bind;
in lib.mkIf config.sane.persist.enable {
source = "${plaintextBacking}/etc/ssh/host_keys";
};
# let openssh find our host keys
services.openssh.hostKeys = [
{ type = "rsa"; bits = 4096; path = "/etc/ssh/host_keys/ssh_host_rsa_key"; }
{ type = "ed25519"; path = "/etc/ssh/host_keys/ssh_host_ed25519_key"; }
];
services.openssh.knownHosts =
let
host-keys = filter (k: k.user == "root") (attrValues config.sane.ssh.pubkeys);
in lib.mkMerge (builtins.map (key: {
"${key.host}".publicKey = key.typedPubkey;
}) host-keys);
};
}