sshguard: new package

lib/maintainers.nix

@@ -446,6 +446,7 @@
   s1lvester = "Markus Silvester <s1lvester@bockhacker.me>";
   samuelrivas = "Samuel Rivas <samuelrivas@gmail.com>";
   sander = "Sander van der Burg <s.vanderburg@tudelft.nl>";
+  sargon = "Daniel Ehlers <danielehlers@mindeye.net>";
   schmitthenner = "Fabian Schmitthenner <development@schmitthenner.eu>";
   schneefux = "schneefux <schneefux+nixos_pkg@schneefux.xyz>";
   schristo = "Scott Christopher <schristopher@konputa.com>";

nixos/modules/module-list.nix

@@ -517,8 +517,9 @@
   ./services/security/munge.nix
   ./services/security/oauth2_proxy.nix
   ./services/security/physlock.nix
-  ./services/security/torify.nix
+  ./services/security/sshguard.nix
   ./services/security/tor.nix
+  ./services/security/torify.nix
   ./services/security/torsocks.nix
   ./services/system/cgmanager.nix
   ./services/system/cloud-init.nix

nixos/modules/services/security/sshguard.nix

@@ -0,0 +1,140 @@
+{ 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.systemPackages = [ pkgs.sshguard pkgs.iptables pkgs.ipset ];
+
+    environment.etc."sshguard.conf".text = let 
+        list_services = ( name:  "-t ${name} ");
+      in ''
+        BACKEND="${pkgs.sshguard}/libexec/sshg-fw-ipset"
+        LOGREADER="LANG=C ${pkgs.systemd}/bin/journalctl -afb -p info -n1 ${toString (map list_services cfg.services)} -o cat"
+      '';
+
+    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 = [ pkgs.iptables pkgs.ipset pkgs.iproute pkgs.systemd ];
+
+        postStart = ''
+          mkdir -p /var/lib/sshguard
+          ${pkgs.ipset}/bin/ipset -quiet create -exist sshguard4 hash:ip family inet
+          ${pkgs.ipset}/bin/ipset -quiet create -exist sshguard6 hash:ip family inet6
+          ${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
+                list_whitelist = ( name:  "-w ${name} ");
+              in ''
+                 ${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)}
+              '';
+            PIDFile = "/run/sshguard/sshguard.pid";
+            Restart = "always";
+
+            ReadOnlyDirectories = "/";
+            ReadWriteDirectories = "/run/sshguard /var/lib/sshguard";
+            RuntimeDirectory = "sshguard";
+            CapabilityBoundingSet = "CAP_NET_ADMIN CAP_NET_RAW";
+         };
+      };
+  };
+}

pkgs/tools/security/sshguard/0001-Remove-the-unnecessary-from-ipset-cmds.patch

@@ -0,0 +1,27 @@
+From 11f0d238d3149c31c4440b8f6a58fe6a00b82d3a Mon Sep 17 00:00:00 2001
+From: Daniel Aleksandersen <code@daniel.priv.no>
+Date: Mon, 13 Mar 2017 16:29:33 +0100
+Subject: [PATCH 1/3] Remove the unnecessary = from ipset cmds
+
+---
+ src/fw/sshg-fw-ipset.sh | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/fw/sshg-fw-ipset.sh b/src/fw/sshg-fw-ipset.sh
+index 510bc2c..dc7f86b 100644
+--- a/src/fw/sshg-fw-ipset.sh
++++ b/src/fw/sshg-fw-ipset.sh
+@@ -3,8 +3,8 @@
+ # This file is part of SSHGuard.
+ 
+ fw_init() {
+-    ipset -quiet create -exist sshguard4 hash:ip family=inet
+-    ipset -quiet create -exist sshguard6 hash:ip family=inet6
++    ipset -quiet create -exist sshguard4 hash:ip family inet
++    ipset -quiet create -exist sshguard6 hash:ip family inet6
+ }
+ 
+ fw_block() {
+-- 
+2.10.0
+

pkgs/tools/security/sshguard/default.nix

@@ -0,0 +1,32 @@
+{ stdenv, fetchurl, autoreconfHook, yacc, flex}:
+
+
+stdenv.mkDerivation rec {
+  version = "2.0.0";
+  name = "sshguard-${version}";
+
+  src = fetchurl {
+    url = "mirror://sourceforge/sshguard/sshguard-2.0.0.tar.gz";
+    sha256 = "e87c6c4a6dddf06f440ea76464eb6197869c0293f0a60ffa51f8a6a0d7b0cb06";
+  };
+
+  doCheck = true;
+
+  nativeBuildInputs = [ autoreconfHook yacc flex ];
+
+  configureFlags = [ "--sysconfdir=/etc" ];
+
+  patches = [ ./0001-Remove-the-unnecessary-from-ipset-cmds.patch ];
+
+  meta = with stdenv.lib; {
+    description = "SSHGuard protects hosts from brute-force attacks";
+    longDescription = ''
+      SSHGuard can read log messages from various input sources. Log messages are parsed, line-by-line, for recognized patterns.
+      If an attack, such as several login failures within a few seconds, is detected, the offending IP is blocked.
+    '';
+    homepage = https://sshguard.net;
+    license = licenses.bsd3;
+    maintainers = with maintainers; [ sargon ];
+    platforms = with platforms; linux ++ darwin ++ freebsd ++ netbsd ++ openbsd;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -3912,6 +3912,8 @@ with pkgs;
 
   snort = callPackage ../applications/networking/ids/snort { };
 
+  sshguard = callPackage ../tools/security/sshguard {};
+
   softhsm = callPackage ../tools/security/softhsm { };
 
   solr = callPackage ../servers/search/solr { };