nixpkgs/nixos/modules/services/security/sshguard.nix
Ashish SHUKLA d3c2b992d4
sshguard: do not create ipset in post-start
Upstream switched to a different type of ipset table, whereas we
create ipset in post-start which overrides upstream, and renders
sshguard ineffective.

Remove ipset creation from post-start, and let it get automatically
by upstream script (sshg-fw-ipset) as part of startup
2019-07-27 10:59:50 +05:30

141 lines
4.1 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.sshguard;
in {
###### interface
options = {
services.sshguard = {
enable = mkOption {
default = false;
type = types.bool;
description = "Whether to enable the sshguard service.";
};
attack_threshold = mkOption {
default = 30;
type = types.int;
description = ''
Block attackers when their cumulative attack score exceeds threshold. Most attacks have a score of 10.
'';
};
blacklist_threshold = mkOption {
default = null;
example = 120;
type = types.nullOr types.int;
description = ''
Blacklist an attacker when its score exceeds threshold. Blacklisted addresses are loaded from and added to blacklist-file.
'';
};
blacklist_file = mkOption {
default = "/var/lib/sshguard/blacklist.db";
type = types.path;
description = ''
Blacklist an attacker when its score exceeds threshold. Blacklisted addresses are loaded from and added to blacklist-file.
'';
};
blocktime = mkOption {
default = 120;
type = types.int;
description = ''
Block attackers for initially blocktime seconds after exceeding threshold. Subsequent blocks increase by a factor of 1.5.
sshguard unblocks attacks at random intervals, so actual block times will be longer.
'';
};
detection_time = mkOption {
default = 1800;
type = types.int;
description = ''
Remember potential attackers for up to detection_time seconds before resetting their score.
'';
};
whitelist = mkOption {
default = [ ];
example = [ "198.51.100.56" "198.51.100.2" ];
type = types.listOf types.str;
description = ''
Whitelist a list of addresses, hostnames, or address blocks.
'';
};
services = mkOption {
default = [ "sshd" ];
example = [ "sshd" "exim" ];
type = types.listOf types.str;
description = ''
Systemd services sshguard should receive logs of.
'';
};
};
};
###### implementation
config = mkIf cfg.enable {
environment.etc."sshguard.conf".text = let
args = lib.concatStringsSep " " ([
"-afb"
"-p info"
"-o cat"
"-n1"
] ++ (map (name: "-t ${escapeShellArg name}") cfg.services));
in ''
BACKEND="${pkgs.sshguard}/libexec/sshg-fw-ipset"
LOGREADER="LANG=C ${pkgs.systemd}/bin/journalctl ${args}"
'';
systemd.services.sshguard = {
description = "SSHGuard brute-force attacks protection system";
wantedBy = [ "multi-user.target" ];
after = [ "network.target" ];
partOf = optional config.networking.firewall.enable "firewall.service";
path = with pkgs; [ iptables ipset iproute systemd ];
postStart = ''
${pkgs.iptables}/bin/iptables -I INPUT -m set --match-set sshguard4 src -j DROP
${pkgs.iptables}/bin/ip6tables -I INPUT -m set --match-set sshguard6 src -j DROP
'';
preStop = ''
${pkgs.iptables}/bin/iptables -D INPUT -m set --match-set sshguard4 src -j DROP
${pkgs.iptables}/bin/ip6tables -D INPUT -m set --match-set sshguard6 src -j DROP
'';
unitConfig.Documentation = "man:sshguard(8)";
serviceConfig = {
Type = "simple";
ExecStart = let
args = lib.concatStringsSep " " ([
"-a ${toString cfg.attack_threshold}"
"-p ${toString cfg.blocktime}"
"-s ${toString cfg.detection_time}"
(optionalString (cfg.blacklist_threshold != null) "-b ${toString cfg.blacklist_threshold}:${cfg.blacklist_file}")
] ++ (map (name: "-w ${escapeShellArg name}") cfg.whitelist));
in "${pkgs.sshguard}/bin/sshguard ${args}";
Restart = "always";
ProtectSystem = "strict";
ProtectHome = "tmpfs";
RuntimeDirectory = "sshguard";
StateDirectory = "sshguard";
CapabilityBoundingSet = "CAP_NET_ADMIN CAP_NET_RAW";
};
};
};
}