nixpkgs/nixos/modules/services/mail/postsrsd.nix

350 lines
11 KiB
Nix

{
config,
lib,
pkgs,
utils,
...
}:
let
cfg = config.services.postsrsd;
inherit (lib)
concatMapStringsSep
concatMapAttrsStringSep
isBool
isFloat
isInt
isPath
isString
isList
mkEnableOption
mkPackageOption
mkRemovedOptionModule
mkRenamedOptionModule
;
# This is a implementation of a simple libconfuse config renderer sufficient
# for the postsrsd configuration file complexity.
# TODO: Replace with pkgs.formats.libconfuse, once implemented (https://github.com/NixOS/nixpkgs/issues/401565)
renderValue =
value:
if isBool value then
if value then "true" else "false"
else if isString value || isPath value then
builtins.toJSON value # for escaping
else if isInt value || isFloat value then
toString value
else if isList value then
"{${concatMapStringsSep "," renderValue value}}"
else
throw "postsrsd: unsupported value type in settings option";
renderAttr =
attrs: concatMapAttrsStringSep "\n" (name: value: "${name} = ${renderValue value}") attrs;
configFile = pkgs.writeText "postsrsd.conf" (
renderAttr (lib.filterAttrsRecursive (_: v: v != null) cfg.settings)
);
in
{
imports = [
(mkRemovedOptionModule [ "services" "postsrsd" "socketPath" ] ''
Configure/reference `services.postsrsd.settings.socketmap` instead. Note that its now required to start with the `inet:` or `unix:` prefix.
'')
(mkRenamedOptionModule
[ "services" "postsrsd" "domains" ]
[ "services" "postsrsd" "settings" "domains" ]
)
(mkRenamedOptionModule
[ "services" "postsrsd" "separator" ]
[ "services" "postsrsd" "settings" "separator" ]
)
]
++
map
(
name:
lib.mkRemovedOptionModule [ "services" "postsrsd" name ] ''
`postsrsd` was upgraded to `>= 2.0.0`, with some different behaviors and configuration settings:
- NixOS Release Notes: https://nixos.org/manual/nixos/unstable/release-notes#sec-nixpkgs-release-25.05-incompatibilities
- NixOS Options Reference: https://nixos.org/manual/nixos/unstable/options#opt-services.postsrsd.enable
- Migration instructions: https://github.com/roehling/postsrsd/blob/2.0.10/README.rst#migrating-from-version-1x
- Postfix Setup: https://github.com/roehling/postsrsd/blob/2.0.10/README.rst#postfix-setup
''
)
[
"domain"
"forwardPort"
"reversePort"
"timeout"
"excludeDomains"
];
options = {
services.postsrsd = {
enable = mkEnableOption "the postsrsd SRS server for Postfix.";
package = mkPackageOption pkgs "postsrsd" { };
secretsFile = lib.mkOption {
type = lib.types.path;
default = "/var/lib/postsrsd/postsrsd.secret";
description = ''
Secret keys used for signing and verification.
::: {.note}
The secret will be generated, if it does not exist at the given path.
:::
'';
};
settings = lib.mkOption {
type = lib.types.submodule {
freeformType =
with lib.types;
attrsOf (oneOf [
bool
float
int
path
str
(listOf str)
]);
options = {
domains = lib.mkOption {
type = with lib.types; listOf str;
default = [ ];
example = [ "example.com" ];
description = ''
List of local domains, that do not require rewriting.
'';
};
secrets-file = lib.mkOption {
type = lib.types.str;
default = "\${CREDENTIALS_DIRECTORY}/secrets-file";
readOnly = true;
description = ''
Path to the file containing the secret keys.
::: {.note}
Secrets are passed using `LoadCredential=` on the systemd unit,
so this options is read-only.
Configure {option}`services.postsrsd.secretsFile` instead.
'';
};
separator = lib.mkOption {
type = lib.types.enum [
"-"
"="
"+"
];
default = "=";
description = ''
SRS tag separator used in generated sender addresses.
Unless you have a very good reason, you should leave this
setting at its default.
'';
};
srs-domain = lib.mkOption {
type = with lib.types; nullOr str;
default = null;
example = "srs.example.com";
description = ''
Dedicated mail domain used for ephemeral SRS envelope addresses.
Recommended to configure, when hosting multiple unrelated mail
domains (e.g. for different customers), to prevent privacy
issues.
Set to `null` to not configure any `srs-domain`.
'';
};
socketmap = lib.mkOption {
type = lib.types.strMatching "^(unix|inet):.+";
default = "unix:/run/postsrsd/socket";
example = "inet:localhost:10003";
description = ''
Listener configuration in socket map format native to Postfix configuration.
'';
};
chroot-dir = lib.mkOption {
type = lib.types.str;
default = "";
readOnly = true;
description = ''
Path to chroot into at runtime as an additional layer of protection.
::: {.note}
We confine the runtime environment through systemd hardening instead, so this option is read-only.
:::
'';
};
unprivileged-user = lib.mkOption {
type = lib.types.str;
default = "";
readOnly = true;
description = ''
Unprivileged user to drop privileges to.
::: {.note}
Our systemd unit never runs postsrsd as a privileged process, so this option is read-only.
:::
'';
};
};
};
default = { };
description = ''
Configuration options for the postsrsd.conf file.
See the [example configuration](https://github.com/roehling/postsrsd/blob/${cfg.package.version}/doc/postsrsd.conf) for possible values.
'';
};
configurePostfix = lib.mkOption {
type = lib.types.bool;
default = true;
description = ''
Whether to configure the required settings to use postsrsd in the local Postfix instance.
'';
};
user = lib.mkOption {
type = lib.types.str;
default = "postsrsd";
description = "User for the daemon";
};
group = lib.mkOption {
type = lib.types.str;
default = "postsrsd";
description = "Group for the daemon";
};
};
};
config = lib.mkMerge [
(lib.mkIf (cfg.enable && cfg.configurePostfix && config.services.postfix.enable) {
services.postfix.settings.main = {
# https://github.com/roehling/postsrsd#configuration
sender_canonical_maps = "socketmap:${cfg.settings.socketmap}:forward";
sender_canonical_classes = "envelope_sender";
recipient_canonical_maps = "socketmap:${cfg.settings.socketmap}:reverse";
recipient_canonical_classes = [
"envelope_recipient"
"header_recipient"
];
};
users.users.postfix.extraGroups = [ cfg.group ];
})
(lib.mkIf cfg.enable {
users.users = lib.optionalAttrs (cfg.user == "postsrsd") {
postsrsd = {
group = cfg.group;
uid = config.ids.uids.postsrsd;
};
};
users.groups = lib.optionalAttrs (cfg.group == "postsrsd") {
postsrsd.gid = config.ids.gids.postsrsd;
};
systemd.services.postsrsd-generate-secrets = {
path = [ pkgs.coreutils ];
script = ''
if [ -e "${cfg.secretsFile}" ]; then
echo "Secrets file exists. Nothing to do!"
else
echo "WARNING: secrets file not found, autogenerating!"
DIR="$(dirname "${cfg.secretsFile}")"
install -m 750 -o ${cfg.user} -g ${cfg.group} -d "$DIR"
install -m 600 -o ${cfg.user} -g ${cfg.group} <(dd if=/dev/random bs=18 count=1 | base64) "${cfg.secretsFile}"
fi
'';
serviceConfig = {
Type = "oneshot";
};
};
environment.etc."postsrsd.conf".source = configFile;
systemd.services.postsrsd = {
description = "PostSRSd SRS rewriting server";
after = [
"network.target"
"postsrsd-generate-secrets.service"
];
before = [ "postfix.service" ];
wantedBy = [ "multi-user.target" ];
requires = [ "postsrsd-generate-secrets.service" ];
restartTriggers = [ configFile ];
serviceConfig = {
ExecStart = utils.escapeSystemdExecArgs [
(lib.getExe cfg.package)
"-C"
"/etc/postsrsd.conf"
];
User = cfg.user;
Group = cfg.group;
RuntimeDirectory = "postsrsd";
RuntimeDirectoryMode = "0750";
LoadCredential = "secrets-file:${cfg.secretsFile}";
CapabilityBoundingSet = [ "" ];
LockPersonality = true;
MemoryDenyWriteExecute = true;
NoNewPrivileges = true;
PrivateDevices = true;
PrivateMounts = true;
PrivateNetwork = lib.hasPrefix "unix:" cfg.settings.socketmap;
PrivateTmp = true;
PrivateUsers = true;
ProtectControlGroups = true;
ProtectHome = true;
ProtectHostname = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
ProtectKernelTunables = true;
ProtectSystem = "strict";
ProtectProc = "invisible";
ProcSubset = "pid";
RemoveIPC = true;
RestrictAddressFamilies =
if lib.hasPrefix "unix:" cfg.settings.socketmap then
[ "AF_UNIX" ]
else
[
"AF_INET"
"AF_INET6"
];
RestrictNamespaces = true;
RestrictRealtime = true;
RestrictSUIDSGID = true;
SystemCallArchitectures = "native";
SystemCallFilter = [
"@system-service"
"~@privileged @resources"
];
UMask = "0027";
};
};
})
];
# package version referenced in option documentation
meta.buildDocsInSandbox = false;
}