141 lines
4.5 KiB
Nix
141 lines
4.5 KiB
Nix
{ config, lib, pkgs, ... }:
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with lib;
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let
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cfg = config.services.sshguard;
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in {
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###### interface
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options = {
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services.sshguard = {
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enable = mkOption {
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default = false;
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type = types.bool;
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description = "Whether to enable the sshguard service.";
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};
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attack_threshold = mkOption {
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default = 30;
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type = types.int;
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description = ''
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Block attackers when their cumulative attack score exceeds threshold. Most attacks have a score of 10.
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'';
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};
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blacklist_threshold = mkOption {
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default = null;
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example = 120;
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type = types.nullOr types.int;
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description = ''
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Blacklist an attacker when its score exceeds threshold. Blacklisted addresses are loaded from and added to blacklist-file.
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'';
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};
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blacklist_file = mkOption {
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default = "/var/lib/sshguard/blacklist.db";
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type = types.path;
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description = ''
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Blacklist an attacker when its score exceeds threshold. Blacklisted addresses are loaded from and added to blacklist-file.
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'';
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};
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blocktime = mkOption {
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default = 120;
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type = types.int;
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description = ''
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Block attackers for initially blocktime seconds after exceeding threshold. Subsequent blocks increase by a factor of 1.5.
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sshguard unblocks attacks at random intervals, so actual block times will be longer.
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'';
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};
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detection_time = mkOption {
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default = 1800;
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type = types.int;
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description = ''
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Remember potential attackers for up to detection_time seconds before resetting their score.
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'';
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};
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whitelist = mkOption {
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default = [ ];
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example = [ "198.51.100.56" "198.51.100.2" ];
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type = types.listOf types.str;
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description = ''
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Whitelist a list of addresses, hostnames, or address blocks.
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'';
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};
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services = mkOption {
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default = [ "sshd" ];
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example = [ "sshd" "exim" ];
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type = types.listOf types.str;
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description = ''
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Systemd services sshguard should receive logs of.
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'';
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};
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};
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};
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###### implementation
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config = mkIf cfg.enable {
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environment.systemPackages = [ pkgs.sshguard pkgs.iptables pkgs.ipset ];
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environment.etc."sshguard.conf".text = let
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list_services = ( name: "-t ${name} ");
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in ''
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BACKEND="${pkgs.sshguard}/libexec/sshg-fw-ipset"
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LOGREADER="LANG=C ${pkgs.systemd}/bin/journalctl -afb -p info -n1 ${toString (map list_services cfg.services)} -o cat"
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'';
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systemd.services.sshguard =
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{ description = "SSHGuard brute-force attacks protection system";
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wantedBy = [ "multi-user.target" ];
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after = [ "network.target" ];
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partOf = optional config.networking.firewall.enable "firewall.service";
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path = [ pkgs.iptables pkgs.ipset pkgs.iproute pkgs.systemd ];
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postStart = ''
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mkdir -p /var/lib/sshguard
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${pkgs.ipset}/bin/ipset -quiet create -exist sshguard4 hash:ip family inet
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${pkgs.ipset}/bin/ipset -quiet create -exist sshguard6 hash:ip family inet6
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${pkgs.iptables}/bin/iptables -I INPUT -m set --match-set sshguard4 src -j DROP
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${pkgs.iptables}/bin/ip6tables -I INPUT -m set --match-set sshguard6 src -j DROP
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'';
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preStop = ''
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${pkgs.iptables}/bin/iptables -D INPUT -m set --match-set sshguard4 src -j DROP
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${pkgs.iptables}/bin/ip6tables -D INPUT -m set --match-set sshguard6 src -j DROP
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'';
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unitConfig.Documentation = "man:sshguard(8)";
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serviceConfig = {
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Type = "simple";
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ExecStart = let
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list_whitelist = ( name: "-w ${name} ");
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in ''
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${pkgs.sshguard}/bin/sshguard -a ${toString cfg.attack_threshold} ${optionalString (cfg.blacklist_threshold != null) "-b ${toString cfg.blacklist_threshold}:${cfg.blacklist_file} "}-i /run/sshguard/sshguard.pid -p ${toString cfg.blocktime} -s ${toString cfg.detection_time} ${toString (map list_whitelist cfg.whitelist)}
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'';
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PIDFile = "/run/sshguard/sshguard.pid";
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Restart = "always";
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ReadOnlyDirectories = "/";
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ReadWriteDirectories = "/run/sshguard /var/lib/sshguard";
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RuntimeDirectory = "sshguard";
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CapabilityBoundingSet = "CAP_NET_ADMIN CAP_NET_RAW";
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};
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};
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};
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}
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