153 lines
4.2 KiB
Nix
153 lines
4.2 KiB
Nix
{ config, lib, pkgs, ... }:
|
|
|
|
with lib;
|
|
|
|
let
|
|
|
|
cfg = config.services.fail2ban;
|
|
|
|
fail2banConf = pkgs.writeText "fail2ban.conf" cfg.daemonConfig;
|
|
|
|
jailConf = pkgs.writeText "jail.conf"
|
|
(concatStringsSep "\n" (attrValues (flip mapAttrs cfg.jails (name: def:
|
|
optionalString (def != "")
|
|
''
|
|
[${name}]
|
|
${def}
|
|
''))));
|
|
|
|
in
|
|
|
|
{
|
|
|
|
###### interface
|
|
|
|
options = {
|
|
|
|
services.fail2ban = {
|
|
enable = mkOption {
|
|
default = false;
|
|
type = types.bool;
|
|
description = "Whether to enable the fail2ban service.";
|
|
};
|
|
|
|
daemonConfig = mkOption {
|
|
default =
|
|
''
|
|
[Definition]
|
|
loglevel = INFO
|
|
logtarget = SYSLOG
|
|
socket = /run/fail2ban/fail2ban.sock
|
|
pidfile = /run/fail2ban/fail2ban.pid
|
|
'';
|
|
type = types.lines;
|
|
description =
|
|
''
|
|
The contents of Fail2ban's main configuration file. It's
|
|
generally not necessary to change it.
|
|
'';
|
|
};
|
|
|
|
jails = mkOption {
|
|
default = { };
|
|
example =
|
|
{ "apache-nohome-iptables" =
|
|
''
|
|
# Block an IP address if it accesses a non-existent
|
|
# home directory more than 5 times in 10 minutes,
|
|
# since that indicates that it's scanning.
|
|
filter = apache-nohome
|
|
action = iptables-multiport[name=HTTP, port="http,https"]
|
|
logpath = /var/log/httpd/error_log*
|
|
findtime = 600
|
|
bantime = 600
|
|
maxretry = 5
|
|
'';
|
|
};
|
|
type = types.attrsOf types.lines;
|
|
description =
|
|
''
|
|
The configuration of each Fail2ban “jail”. A jail
|
|
consists of an action (such as blocking a port using
|
|
<command>iptables</command>) that is triggered when a
|
|
filter applied to a log file triggers more than a certain
|
|
number of times in a certain time period. Actions are
|
|
defined in <filename>/etc/fail2ban/action.d</filename>,
|
|
while filters are defined in
|
|
<filename>/etc/fail2ban/filter.d</filename>.
|
|
'';
|
|
};
|
|
|
|
};
|
|
|
|
};
|
|
|
|
|
|
###### implementation
|
|
|
|
config = mkIf cfg.enable {
|
|
|
|
environment.systemPackages = [ pkgs.fail2ban ];
|
|
|
|
environment.etc."fail2ban/fail2ban.conf".source = fail2banConf;
|
|
environment.etc."fail2ban/jail.conf".source = jailConf;
|
|
environment.etc."fail2ban/action.d".source = "${pkgs.fail2ban}/etc/fail2ban/action.d/*.conf";
|
|
environment.etc."fail2ban/filter.d".source = "${pkgs.fail2ban}/etc/fail2ban/filter.d/*.conf";
|
|
|
|
systemd.services.fail2ban =
|
|
{ description = "Fail2ban Intrusion Prevention System";
|
|
|
|
wantedBy = [ "multi-user.target" ];
|
|
after = [ "network.target" ];
|
|
|
|
restartTriggers = [ fail2banConf jailConf ];
|
|
path = [ pkgs.fail2ban pkgs.iptables ];
|
|
|
|
preStart =
|
|
''
|
|
mkdir -p /run/fail2ban -m 0755
|
|
mkdir -p /var/lib/fail2ban
|
|
'';
|
|
|
|
serviceConfig =
|
|
{ ExecStart = "${pkgs.fail2ban}/bin/fail2ban-server -f";
|
|
ReadOnlyDirectories = "/";
|
|
ReadWriteDirectories = "/run /var/tmp /var/lib";
|
|
CapabilityBoundingSet = "CAP_DAC_READ_SEARCH CAP_NET_ADMIN CAP_NET_RAW";
|
|
};
|
|
|
|
postStart =
|
|
''
|
|
# Wait for the server to start listening.
|
|
for ((n = 0; n < 20; n++)); do
|
|
if fail2ban-client ping; then break; fi
|
|
sleep 0.5
|
|
done
|
|
|
|
# Reload its configuration.
|
|
fail2ban-client reload
|
|
'';
|
|
};
|
|
|
|
# Add some reasonable default jails. The special "DEFAULT" jail
|
|
# sets default values for all other jails.
|
|
services.fail2ban.jails.DEFAULT =
|
|
''
|
|
ignoreip = 127.0.0.1/8
|
|
bantime = 600
|
|
findtime = 600
|
|
maxretry = 3
|
|
backend = systemd
|
|
'';
|
|
|
|
# Block SSH if there are too many failing connection attempts.
|
|
services.fail2ban.jails.ssh-iptables =
|
|
''
|
|
filter = sshd
|
|
action = iptables[name=SSH, port=ssh, protocol=tcp]
|
|
maxretry = 5
|
|
'';
|
|
|
|
};
|
|
|
|
}
|