From 3d27b1c8c9a53624a82a9b486810e51b9efa1517 Mon Sep 17 00:00:00 2001
From: h7x4 <h7x4@nani.wtf>
Date: Sat, 30 Mar 2024 00:02:22 +0100
Subject: [PATCH] base/nginx: 444 requests to nonexistent virtualhosts

---
 base.nix                   | 17 ++++++++
 modules/snakeoil-certs.nix | 83 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 modules/snakeoil-certs.nix

diff --git a/base.nix b/base.nix
index a11ee84..8ac0735 100644
--- a/base.nix
+++ b/base.nix
@@ -3,6 +3,7 @@
 {
   imports = [
     ./users
+    ./modules/snakeoil-certs.nix
   ];
 
   networking.domain = "pvv.ntnu.no";
@@ -82,5 +83,21 @@
     settings.PermitRootLogin = "yes";
   };
 
+  # nginx return 444 for all nonexistent virtualhosts
 
+  systemd.services.nginx.after = [ "generate-snakeoil-certs.service" ];
+
+  environment.snakeoil-certs = lib.mkIf (config.services.nginx.enable) {
+    "/etc/certs/nginx" = {
+      owner = "nginx";
+      group = "nginx";
+    };
+  };
+
+  services.nginx.virtualHosts."_" = lib.mkIf (config.services.nginx.enable) {
+    sslCertificate = "/etc/certs/nginx.crt";
+    sslCertificateKey = "/etc/certs/nginx.key";
+    addSSL = true;
+    extraConfig = "return 444;";
+  };
 }
diff --git a/modules/snakeoil-certs.nix b/modules/snakeoil-certs.nix
new file mode 100644
index 0000000..e280e83
--- /dev/null
+++ b/modules/snakeoil-certs.nix
@@ -0,0 +1,83 @@
+{ config, pkgs, lib, ... }:
+let
+  cfg = config.environment.snakeoil-certs;
+in
+{
+  options.environment.snakeoil-certs = lib.mkOption {
+    default = { };
+    description = "Self signed certs, which are rotated regularly";
+    type = lib.types.attrsOf (lib.types.submodule ({ name, ... }: {
+      options = {
+        owner = lib.mkOption {
+          type = lib.types.str;
+          default = "root";
+        };
+        group = lib.mkOption {
+          type = lib.types.str;
+          default = "root";
+        };
+        mode = lib.mkOption {
+          type = lib.types.str;
+          default = "0660";
+        };
+        daysValid = lib.mkOption {
+          type = lib.types.str;
+          default = "90";
+        };
+        extraOpenSSLArgs = lib.mkOption {
+          type = with lib.types; listOf str;
+          default = [ ];
+        };
+        certificate = lib.mkOption {
+          type = lib.types.str;
+          default = "${name}.crt";
+        };
+        certificateKey = lib.mkOption {
+          type = lib.types.str;
+          default = "${name}.key";
+        };
+	subject = {
+	  type = lib.types.str;
+	  default = "/C=NO/O=Programvareverkstedet/CN=*.pvv.ntnu.no/emailAddress=drift@pvv.ntnu.no";
+	};
+      };
+    }));
+  };
+
+  config = {
+    systemd.services."generate-snakeoil-certs" = {
+      enable = true;
+      serviceConfig.Type = "oneshot";
+      script = let
+        openssl = lib.getExe pkgs.openssl;
+      in lib.concatMapStringsSep "\n----------------\n" ({ name, value }: ''
+        mkdir -p $(dirname "${value.certificate}") $(dirname "${value.certificateKey}")
+        if ! ${openssl} x509 -checkend 86400 -noout -in ${value.certificate}
+        then
+           echo "Regenerating '${value.certificate}'"
+           ${openssl} req \
+             -newkey rsa:4096 \
+             -new -x509 \
+             -days "${toString value.daysValid}" \
+             -nodes \
+             -subj "${value.subject}" \
+             -out "${value.certificate}" \
+             -keyout "${value.certificateKey}" \
+             ${lib.escapeShellArgs value.extraOpenSSLArgs}
+        fi
+        chown "${value.owner}:${value.group}" "${value.certificate}"
+        chown "${value.owner}:${value.group}" "${value.certificateKey}"
+        chmod "${value.mode}" "${value.certificate}"
+        chmod "${value.mode}" "${value.certificateKey}"
+      '') (lib.attrsToList cfg);
+    };
+    systemd.timers."generate-snakeoil-certs" = {
+      wantedBy = [ "timers.target" ];
+      timerConfig = {
+        OnCalendar = "*-*-* 02:00:00";
+        Persistent = true;
+        Unit = "generate-snakeoil-certs.service";
+      };
+    };
+  };
+}