agenix/modules/age.nix
2020-09-09 20:44:45 -07:00

102 lines
3.1 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.age;
users = config.users.users;
identities = builtins.concatStringsSep " " (map (path: "-i ${path}") cfg.sshKeyPaths);
installSecret = secretType: ''
TMP_FILE="${secretType.path}.tmp"
(umask 0400; ${pkgs.age}/bin/age --decrypt ${identities} -o "$TMP_FILE" "${secretType.file}")
chmod ${secretType.mode} "$TMP_FILE"
chown ${secretType.owner}:${secretType.group} "$TMP_FILE"
mv -f "$TMP_FILE" '${secretType.path}'
'';
rootOwnedSecrets = builtins.filter (st: st.owner == "root" && st.group == "root") (builtins.attrValues cfg.secrets);
installRootOwnedSecrets = builtins.concatStringsSep "\n" (map installSecret rootOwnedSecrets);
nonRootSecrets = builtins.filter (st: st.owner != "root" && st.group != "root") (builtins.attrValues cfg.secrets);
installNonRootSecrets = builtins.concatStringsSep "\n" (map installSecret nonRootSecrets);
secretType = types.submodule ({ config, ... }: {
options = {
name = mkOption {
type = types.str;
default = config._module.args.name;
description = ''
Name of the file used in /run/secrets
'';
};
file = mkOption {
type = types.path;
description = ''
Age file the secret is loaded from.
'';
};
path = mkOption {
type = types.str;
default = "/run/secrets/${config.name}";
description = ''
Path where the decrypted secret is installed.
'';
};
mode = mkOption {
type = types.str;
default = "0400";
description = ''
Permissions mode of the in octal.
'';
};
owner = mkOption {
type = types.str;
default = "root";
description = ''
User of the file.
'';
};
group = mkOption {
type = types.str;
default = users.${config.owner}.group;
description = ''
Group of the file.
'';
};
};
});
in {
options.age = {
secrets = mkOption {
type = types.attrsOf secretType;
default = {};
description = ''
Attrset of secrets.
'';
};
sshKeyPaths = mkOption {
type = types.listOf types.path;
default = if config.services.openssh.enable then
map (e: e.path) (lib.filter (e: e.type == "rsa" || e.type == "ed25519") config.services.openssh.hostKeys)
else [];
description = ''
Path to SSH keys to be used as identities in age decryption.
'';
};
};
config = mkIf (cfg.secrets != {}) {
assertions = [{
assertion = cfg.sshKeyPaths != [];
message = "age.sshKeyPaths must be set.";
}];
# Secrets with root owner and group can be installed before users
# exist. This allows user password files to be encrypted.
system.activationScripts.agenixRoot = installRootOwnedSecrets;
system.activationScripts.users.deps = [ "agenixRoot" ];
# Other secrets need to wait for users and groups to exist.
system.activationScripts.agenix = stringAfter [ "users" "groups" ] installNonRootSecrets;
};
}