From d48fb6c13a4eff68e1acb91692ebf9f031bfd135 Mon Sep 17 00:00:00 2001
From: Fugi <me@fugi.dev>
Date: Wed, 4 Oct 2023 18:49:12 +0200
Subject: [PATCH] setup fail2ban

block tor exit nodes
---
 flake.nix            |  1 +
 modules/fail2ban.nix | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 modules/fail2ban.nix

diff --git a/flake.nix b/flake.nix
index 10cbe22..8392cb7 100755
--- a/flake.nix
+++ b/flake.nix
@@ -56,6 +56,7 @@
             ./modules/course-management.nix
             ./modules/courses-phil.nix
             ./modules/gitea.nix
+            ./modules/fail2ban.nix
             {
               sops.defaultSopsFile = ./secrets/quitte.yaml;
             }
diff --git a/modules/fail2ban.nix b/modules/fail2ban.nix
new file mode 100644
index 0000000..f9d8183
--- /dev/null
+++ b/modules/fail2ban.nix
@@ -0,0 +1,40 @@
+{ config, lib, pkgs, ... }:
+{
+  services.fail2ban = {
+    enable = true;
+
+    jails = {
+      tor = ''
+        enabled = true
+        bantime = 25h
+        action = iptables-allports[name=fail2banTOR, protocol=all]
+      '';
+    };
+  };
+
+  environment.etc = {
+    # dummy filter
+    "fail2ban/filter.d/tor.conf".text = ''
+      [Definition]
+      failregex =
+      ignoreregex =
+    '';
+  };
+
+  systemd.services."fail2ban-tor" = {
+    script = ''
+      ${lib.getExe pkgs.curl} -fsSL "https://check.torproject.org/torbulkexitlist" | sed '/^#/d' | while read IP; do
+        ${config.services.fail2ban.package}/bin/fail2ban-client set "tor" banip "$IP" > /dev/null
+      done
+    '';
+  };
+
+  systemd.timers."fail2ban-tor" = {
+    wantedBy = [ "timers.target" ];
+    timerConfig = {
+      OnCalendar = "daily";
+      Persistent = true;
+      Unit = "fail2ban-tor.service";
+    };
+  };
+}