From 110b3af97a8524161cd90e7a2aa5f2c269e4268c Mon Sep 17 00:00:00 2001
From: Defelo <mail@defelo.de>
Date: Thu, 6 Mar 2025 02:00:59 +0100
Subject: [PATCH 1/2] nixos/tests/echoip: use runTest

---
 nixos/tests/all-tests.nix |  2 +-
 nixos/tests/echoip.nix    | 47 +++++++++++++++++++--------------------
 2 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 809440bfbf97..06411420a5dc 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -341,7 +341,7 @@ in {
   early-mount-options = handleTest ./early-mount-options.nix {};
   ec2-config = (handleTestOn ["x86_64-linux"] ./ec2.nix {}).boot-ec2-config or {};
   ec2-nixops = (handleTestOn ["x86_64-linux"] ./ec2.nix {}).boot-ec2-nixops or {};
-  echoip = handleTest ./echoip.nix {};
+  echoip = runTest ./echoip.nix;
   ecryptfs = handleTest ./ecryptfs.nix {};
   fscrypt = handleTest ./fscrypt.nix {};
   fastnetmon-advanced = runTest ./fastnetmon-advanced.nix;
diff --git a/nixos/tests/echoip.nix b/nixos/tests/echoip.nix
index 036018b26438..0e7747d713c1 100644
--- a/nixos/tests/echoip.nix
+++ b/nixos/tests/echoip.nix
@@ -1,29 +1,28 @@
-import ./make-test-python.nix (
-  { lib, ... }:
-  {
-    name = "echoip";
-    meta.maintainers = with lib.maintainers; [ defelo ];
+{ lib, ... }:
 
-    nodes.machine = {
-      services.echoip = {
-        enable = true;
-        virtualHost = "echoip.local";
-      };
+{
+  name = "echoip";
+  meta.maintainers = with lib.maintainers; [ defelo ];
 
-      networking.hosts = {
-        "127.0.0.1" = [ "echoip.local" ];
-        "::1" = [ "echoip.local" ];
-      };
+  nodes.machine = {
+    services.echoip = {
+      enable = true;
+      virtualHost = "echoip.local";
     };
 
-    testScript = ''
-      machine.wait_for_unit("echoip.service")
-      machine.wait_for_open_port(8080)
+    networking.hosts = {
+      "127.0.0.1" = [ "echoip.local" ];
+      "::1" = [ "echoip.local" ];
+    };
+  };
 
-      resp = machine.succeed("curl -4 http://echoip.local/ip")
-      assert resp.strip() == "127.0.0.1"
-      resp = machine.succeed("curl -6 http://echoip.local/ip")
-      assert resp.strip() == "::1"
-    '';
-  }
-)
+  testScript = ''
+    machine.wait_for_unit("echoip.service")
+    machine.wait_for_open_port(8080)
+
+    resp = machine.succeed("curl -4 http://echoip.local/ip")
+    assert resp.strip() == "127.0.0.1"
+    resp = machine.succeed("curl -6 http://echoip.local/ip")
+    assert resp.strip() == "::1"
+  '';
+}

From eccf6388229ab41dec9b97244fe0432490cbc4cb Mon Sep 17 00:00:00 2001
From: Defelo <mail@defelo.de>
Date: Thu, 6 Mar 2025 02:01:23 +0100
Subject: [PATCH 2/2] nixos/echoip: improve systemd hardening

---
 nixos/modules/services/web-apps/echoip.nix | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/nixos/modules/services/web-apps/echoip.nix b/nixos/modules/services/web-apps/echoip.nix
index 4bfba2ae138a..369ff35f4978 100644
--- a/nixos/modules/services/web-apps/echoip.nix
+++ b/nixos/modules/services/web-apps/echoip.nix
@@ -75,9 +75,12 @@ in
         );
 
         # Hardening
+        AmbientCapabilities = "";
         CapabilityBoundingSet = [ "" ];
-        DeviceAllow = [ "" ];
+        DevicePolicy = "closed";
         LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
         PrivateDevices = true;
         PrivateTmp = true;
         PrivateUsers = true;
@@ -91,15 +94,19 @@ in
         ProtectKernelTunables = true;
         ProtectProc = "invisible";
         ProtectSystem = "strict";
-        RestrictAddressFamilies = [
-          "AF_INET"
-          "AF_INET6"
-          "AF_UNIX"
-        ];
+        RemoveIPC = true;
+        RestrictAddressFamilies = [ "AF_INET AF_INET6 AF_UNIX" ];
         RestrictNamespaces = true;
         RestrictRealtime = true;
         RestrictSUIDSGID = true;
         SystemCallArchitectures = "native";
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged"
+          "~@resources"
+          "setrlimit"
+        ];
+        UMask = "0077";
       };
     };