Setup crowdsec with ssh/firewall/traefik

nixos/viridian/services/crowdsec/acquis.d/appsec.yaml

@@ -0,0 +1,6 @@
+listen_addr: 127.0.0.1:7422
+appsec_config: crowdsecurity/appsec-default
+name: traefik
+source: appsec
+labels:
+  type: appsec

nixos/viridian/services/crowdsec/default.nix

@@ -0,0 +1,94 @@
+{ config, inputs, pkgs, ... }:
+let
+  port = "8080";
+in
+{
+  imports = [
+    inputs.crowdsec.nixosModules.crowdsec
+    inputs.crowdsec.nixosModules.crowdsec-firewall-bouncer
+  ];
+
+  nixpkgs.overlays = [
+    inputs.crowdsec.overlays.default
+  ];
+
+  age.secrets.enrollment-key = {
+    rekeyFile = ./enrollment_key.age;
+    owner = "crowdsec";
+    group = "crowdsec";
+  };
+
+  services.crowdsec = let
+    yaml = (pkgs.formats.yaml {}).generate;
+    acquisitions_file = yaml "acquisitions.yaml" {
+      source = "journalctl";
+      journalctl_filter = ["_SYSTEMD_UNIT=sshd.service"];
+      labels.type = "syslog";
+    };
+  in {
+    enable = true;
+    allowLocalJournalAccess = true;
+    enrollKeyFile = config.age.secrets.enrollment-key.path;
+    settings = {
+      api.server = {
+        listen_uri = "127.0.0.1:${port}";
+      };
+      crowdsec_service.acquisition_path = acquisitions_file;
+      crowdsec_service.acquisition_dir = ./acquis.d;
+    };
+  };
+
+  services.crowdsec-firewall-bouncer = {
+    enable = true;
+    settings = {
+      api_key = "2025f0be-35ca-406c-8737-810321c918c2";
+      api_url = "http://localhost:${port}";
+    };
+  };
+
+  systemd.services.crowdsec.serviceConfig = {
+    ExecStartPre = let
+      bouncer = pkgs.writeScriptBin "register-bouncer" ''
+        #!${pkgs.runtimeShell}
+        set -eu
+        set -o pipefail
+
+        if ! cscli bouncers list | grep -q "firewall-bouncer"; then
+          cscli bouncers add "firewall-bouncer" --key "2025f0be-35ca-406c-8737-810321c918c2"
+        fi
+
+        if ! cscli bouncers list | grep -q "traefik-bouncer"; then
+          cscli bouncers add "traefik-bouncer" --key "18c725d5-3a22-4331-a8e8-abfd3018a7c0"
+        fi
+      '';
+      scenario = pkgs.writeScriptBin "install-scenario" ''
+        #!${pkgs.runtimeShell}
+        set -eu
+        set -o pipefail
+
+        if ! cscli collections list | grep -q "crowdsecurity/linux"; then
+          cscli collections install "crowdsecurity/linux"
+        fi
+
+        if ! cscli collections list | grep -q "crowdsecurity/appsec-virtual-patching"; then
+          cscli collections install "crowdsecurity/appsec-virtual-patching"
+        fi
+
+        if ! cscli collections list | grep -q "crowdsecurity/appsec-generic-rules"; then
+          cscli collections install "crowdsecurity/appsec-generic-rules"
+        fi
+      '';
+    in [
+      "${bouncer}/bin/register-bouncer"
+      "${scenario}/bin/install-scenario"
+    ];
+  };
+
+  environment.persistence."/persist" = {
+    directories = [
+      { directory = "/var/lib/crowdsec"; user = "crowdsec"; group = "crowdsec"; }
+    ];
+    hideMounts = true;
+  };
+}
+

nixos/viridian/services/crowdsec/traefik-bouncer-key.age

@@ -0,0 +1,9 @@
+age-encryption.org/v1
+-> piv-p256 hdSnGw A6O6zvEq05hpB3GxDsrj2rUxr0P031TKreOe3ZAfUpJs
+Ww8Qg1MV5dJoCYQEGSNLUnZdX7dO1cGu3XaQTyn97PA
+-> 0(D-grease b? xbW Qg ~cDE0j!
+s5z0LGzRiWS6lMMphO19nB7qmvXkto4RJrcTSrOtPHbY9Iam2aeYA0qN4faK40Zs
+XPc
+--- q1PoY78SatX6wOKNW549+ndCCrNhveA8dHcHQpF+slk
+l
<0A>¾ß`òŠæ¨=(¡¾è;>Y[)Pfwú.§…óQ²¹¸W5áòØØL©Ã—K£DˆTœY$’µŸ
+ý’Ù¿zñ¨Ã]

nixos/viridian/services/default.nix

@@ -3,6 +3,7 @@
 {
   imports = [
     ./traefik
+    ./crowdsec
     ./minecraft
     ./borgbackup.nix
     ./forgejo.nix

nixos/viridian/services/forgejo.nix

@@ -25,6 +25,7 @@
         "websecure"
       ];
       middlewares = [
+        "crowdsec"
         "geoblock"
       ];
       service = "forgejo";

nixos/viridian/services/lighttpd.nix

@@ -14,6 +14,7 @@
         "websecure"
       ];
       middlewares = [
+        "crowdsec"
         "geoblock"
       ];
       service = "lighttpd";

nixos/viridian/services/traefik/default.nix

@@ -53,10 +53,17 @@
 
       # Install plugins
       experimental.plugins = {
+        # Block or allow requests based on their country of origin.
         geoblock = {
           moduleName = "github.com/PascalMinder/geoblock";
           version = "v0.2.7";
         };
+
+        # Authorize or block requests from IPs based on there reputation and behaviour.
+        bouncer = {
+          moduleName = "github.com/maxlerebourg/crowdsec-bouncer-traefik-plugin";
+          version = "v1.3.2";
+        };
       };
 
       # Network entry points into Traefik

nixos/viridian/services/traefik/middlewares.nix

@@ -1,6 +1,13 @@
-{ ... }:
+{ config, ... }:
 
 {
+  # Crowdsec Local API key for the bouncer.
+  age.secrets.traefik-bouncer-key = {
+    rekeyFile = ../crowdsec/traefik-bouncer-key.age;
+    owner = "traefik";
+    group = "traefik";
+  };
+
   # Attached to the routers, pieces of middleware are a means of tweaking the requests before they are sent to your service
   services.traefik.dynamicConfigOptions.http.middlewares = {
     # Restrict access to admin devices only
@@ -9,12 +16,14 @@
       "192.168.1.101"   # fuchsia
       "10.100.0.2"      # Pixel 6 Pro
     ];
+
     # Restrict access to internal networks
     internal.ipwhitelist.sourcerange = [
       "127.0.0.1/32"    # localhost
       "192.168.1.1/24"  # lan
       "10.100.0.0/24"   # wireguard clients
     ];
+
     # Restrict access based on geo-location
     geoblock.plugin.geoblock = {
       silentStartUp = "false";
@@ -42,6 +51,17 @@
       # Even if an IP stays in the cache for a period of a month, it must be fetch again after a month.
       forceMonthlyUpdate = "true";
     };
+
+    # Disable Crowdsec IP checking but apply Crowdsec Appsec checking. This mode is intended to be used when Crowdsec IP checking is applied at the Firewall Level.
+    crowdsec.plugin.bouncer = {
+      enabled = "true";
+      crowdsecMode = "appsec";
+      crowdsecLapiKeyFile = config.age.secrets.traefik-bouncer-key.path; 
+      crowdsecLapiScheme = "http";
+      crowdsecLapiHost = "127.0.0.1:8080";
+      crowdsecAppsecEnabled = "true";
+      crowdsecAppsecHost = "127.0.0.1:7422";
+    };
   };
 }