nixpkgs/nixos/modules/services/security/haveged.nix
2024-06-14 02:41:42 -04:00

78 lines
2.1 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.haveged;
in
{
###### interface
options = {
services.haveged = {
enable = mkEnableOption ''
haveged entropy daemon, which refills /dev/random when low.
NOTE: does nothing on kernels newer than 5.6
'';
# source for the note https://github.com/jirka-h/haveged/issues/57
refill_threshold = mkOption {
type = types.int;
default = 1024;
description = ''
The number of bits of available entropy beneath which
haveged should refill the entropy pool.
'';
};
};
};
config = mkIf cfg.enable {
# https://github.com/jirka-h/haveged/blob/a4b69d65a8dfc5a9f52ff8505c7f58dcf8b9234f/contrib/Fedora/haveged.service
systemd.services.haveged = {
description = "Entropy Daemon based on the HAVEGE algorithm";
unitConfig = {
Documentation = "man:haveged(8)";
DefaultDependencies = false;
ConditionKernelVersion = "<5.6";
};
wantedBy = [ "sysinit.target" ];
after = [ "systemd-tmpfiles-setup-dev.service" ];
before = [ "sysinit.target" "shutdown.target" "systemd-journald.service" ];
serviceConfig = {
ExecStart = "${pkgs.haveged}/bin/haveged -w ${toString cfg.refill_threshold} --Foreground -v 1";
Restart = "always";
SuccessExitStatus = "137 143";
SecureBits = "noroot-locked";
CapabilityBoundingSet = [ "CAP_SYS_ADMIN" "CAP_SYS_CHROOT" ];
# We can *not* set PrivateTmp=true as it can cause an ordering cycle.
PrivateTmp = false;
PrivateDevices = true;
ProtectSystem = "full";
ProtectHome = true;
ProtectHostname = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
RestrictNamespaces = true;
RestrictRealtime = true;
LockPersonality = true;
MemoryDenyWriteExecute = true;
SystemCallArchitectures = "native";
SystemCallFilter = [ "@system-service" "newuname" "~@mount" ];
SystemCallErrorNumber = "EPERM";
};
};
};
}