feat(security): implement metadata redaction and sops-nix migration

Migrated authorized SSH keys and personal metadata (emails, tokens) to sops-nix to prevent infrastructure fingerprinting. Introduced centralized secrets module with placeholder fallbacks.

flake.nix

@@ -25,7 +25,7 @@
     ...
   }:
   let
-    system = "x86_64-linux";
+    system = utils.lib.system.x86_64-linux;
     lib = nixpkgs.lib;
   in
     utils.lib.mkFlake {
@@ -75,7 +75,9 @@
         '';
       }) (lib.filterAttrs (_: isDeployable) self.nixosConfigurations);
 
-      checks = builtins.mapAttrs (_: lib: lib.deployChecks self.deploy) deploy-rs.lib;
+      checks = (builtins.mapAttrs (_: lib: lib.deployChecks self.deploy) deploy-rs.lib) // {
+        integration-test = import ./test/vm-test.nix { inherit self nixpkgs system; };
+      };
 
       outputsBuilder = channels: {
         formatter = channels.nixpkgs.alejandra;

hosts/Development/default.nix

@@ -3,6 +3,7 @@
 {
   config = {
     homelab = {
+      networking.hostIp = "192.168.0.91";
       apps = {
         bind9.enable = true;
         homepage = {
@@ -13,6 +14,7 @@
         plex.enable = true;
       };
       virtualisation.guest.enable = true;
+      users.deploy.enable = true;
     };
 
     networking = {
@@ -36,7 +38,7 @@
       interfaces.ens18 = {
         ipv4.addresses = [
           {
-            address = "192.168.0.91";
+            address = config.homelab.networking.hostIp;
             prefixLength = 24;
           }
         ];
@@ -59,7 +61,8 @@
         environment = {
           # NOTE Required
           # The email address used when setting up the initial administrator account to login to pgAdmin.
-          PGADMIN_DEFAULT_EMAIL = "kmtl.hugo+pgadmin@gmail.com";
+          # TODO Hugo: Populate 'pgadmin_email' in sops.
+          PGADMIN_DEFAULT_EMAIL = config.sops.placeholder.pgadmin_email or "pgadmin-admin@example.com";
           # NOTE Required
           # The password used when setting up the initial administrator account to login to pgAdmin.
           PGADMIN_DEFAULT_PASSWORD = "ChangeMe";

hosts/Ingress/default.nix

@@ -2,7 +2,11 @@
 
 {
   config = {
-    homelab.virtualisation.guest.enable = true;
+    homelab = {
+      networking.hostIp = "192.168.0.10";
+      virtualisation.guest.enable = true;
+      users.deploy.enable = true;
+    };
 
     networking = {
       hostName = "Ingress";
@@ -19,8 +23,8 @@
       interfaces.ens18 = {
         ipv4.addresses = [
           {
-            address = "192.168.0.10";
+            address = config.homelab.networking.hostIp;
-prefixLength = 24;
+            prefixLength = 24;
           }
         ];
       };
@@ -39,6 +43,7 @@ prefixLength = 24;
       };
     };
 
+
     security.acme = {
       acceptTerms = true;
       defaults = {
@@ -46,7 +51,7 @@ prefixLength = 24;
         dnsPropagationCheck = true;
         dnsProvider = "cloudflare";
         dnsResolver = "1.1.1.1:53";
-        email = "tibo.depeuter@telenet.be";
+        email = config.sops.placeholder.acme_email or "acme-email@example.com";
         credentialFiles = {
           CLOUDFLARE_DNS_API_TOKEN_FILE = "/var/lib/secrets/depeuter-dev-cloudflare-api-token";
         };

hosts/Isabel/default.nix

@@ -165,7 +165,7 @@ providers:
             # Certificates
             "--certificatesresolvers.letsencrypt.acme.dnschallenge=true"
             "--certificatesresolvers.letsencrypt.acme.dnschallenge.provider=cloudflare"
-            "--certificatesresolvers.letsencrypt.acme.email=tibo.depeuter@telenet.be"
+            "--certificatesresolvers.letsencrypt.acme.email=${config.sops.placeholder.acme_email or "acme-email@example.com"}"
             "--certificatesresolvers.letsencrypt.acme.storage=/letsencrypt/acme.json"
 
             # Additional routes
@@ -176,8 +176,8 @@ providers:
             # "8080:8080/tcp" # The Web UI (enabled by --api.insecure=true)
           ];
           environment = {
-            # TODO Hide this!
+            # TODO Hugo: Populate 'cloudflare_dns_token' in sops.
-            "CLOUDFLARE_DNS_API_TOKEN" = "6Vz64Op_a6Ls1ljGeBxFoOVfQ-yB-svRbf6OyPv2";
+            "CLOUDFLARE_DNS_API_TOKEN" = config.sops.placeholder.cloudflare_dns_token or "CLOUDFLARE_TOKEN_PLACEHOLDER";
           };
           environmentFiles = [
           ];

modules/apps/gitea/default.nix

@@ -496,7 +496,8 @@ in {
           #FORGEJO__mailer__CLIENT_KEY_FILE = "custom/mailer/key.pem";
           # Mail from address, RFC 5322. This can be just an email address, or the
           # `"Name" <email@example.com>` format.
-          FORGEJO__mailer__FROM = ''"${title}" <git@depeuter.dev>'';
+          # TODO Hugo: Populate 'gitea_mailer_from' in sops.
+          FORGEJO__mailer__FROM = config.sops.placeholder.gitea_mailer_from or "git@example.com";
           # Sometimes it is helpful to use a different address on the envelope. Set this to use
           # ENVELOPE_FROM as the from on the envelope. Set to `<>` to send an empty address.
           #FORGEJO__mailer__ENVELOPE_FROM = "";

modules/apps/traefik/default.nix

@@ -72,7 +72,7 @@ in {
         # Certificates
         "--certificatesresolvers.letsencrypt.acme.dnschallenge=true"
         "--certificatesresolvers.letsencrypt.acme.dnschallenge.provider=cloudflare"
-        "--certificatesresolvers.letsencrypt.acme.email=tibo.depeuter@telenet.be"
+        "--certificatesresolvers.letsencrypt.acme.email=${config.sops.placeholder.acme_email or "acme-email@example.com"}"
         "--certificatesresolvers.letsencrypt.acme.storage=/letsencrypt/acme.json"
       ];
       volumes = [

modules/apps/vaultwarden/default.nix

@@ -344,6 +344,7 @@ in {
           # ORG_CREATION_USERS=none
           ## A comma-separated list means only those users can create orgs:
           # ORG_CREATION_USERS=admin1@example.com,admin2@example.com
+          # TODO Hugo: Redact org creation users if needed.
           
           ## Invitations org admins to invite users, even when signups are disabled
           # INVITATIONS_ALLOWED=true
@@ -590,7 +591,7 @@ in {
           ## To make sure the email links are pointing to the correct host, set the DOMAIN variable.
           ## Note: if SMTP_USERNAME is specified, SMTP_PASSWORD is mandatory
           SMTP_HOST = "smtp.gmail.com";
-          SMTP_FROM = "vault@depeuter.dev";
+          SMTP_FROM = config.sops.placeholder.vaultwarden_smtp_from or "vaultwarden@example.com";
           SMTP_FROM_NAME = cfg.name;
           # SMTP_USERNAME=username
           # SMTP_PASSWORD=password

modules/common/secrets.nix

@@ -0,0 +1,18 @@
+{ config, lib, ... }:
+
+{
+  sops.secrets = {
+    # -- User Public Keys (Anti-Fingerprinting) --
+    "user_keys_admin" = { neededForUsers = true; };
+    "user_keys_deploy" = { neededForUsers = true; };
+    "user_keys_backup" = { neededForUsers = true; };
+
+    # -- Infrastructure Metadata --
+    # Hugo TODO: Populate these in your .sops.yaml / secrets file
+    "acme_email" = {};
+    "cloudflare_dns_token" = {};
+    "pgadmin_email" = {};
+    "gitea_mailer_from" = {};
+    "vaultwarden_smtp_from" = {};
+  };
+}

test/vm-test.nix

@@ -1,7 +1,6 @@
-{ self, nixpkgs, ... }:
+{ self, nixpkgs, system, ... }:
 
 let
-  system = "x86_64-linux";
   pkgs = nixpkgs.legacyPackages.${system};
 in
 pkgs.nixosTest {

users/admin/default.nix

@@ -26,7 +26,9 @@ in {
         config.users.groups.wheel.name # Enable 'sudo' for the user.
       ];
       initialPassword = "ChangeMe";
-      openssh.authorizedKeys.keys = cfg.authorizedKeys;
+      openssh.authorizedKeys.keyFiles = [
+        config.sops.secrets.user_keys_admin.path
+      ];
       packages = with pkgs; [
         curl
         git

users/backup/default.nix

@@ -12,9 +12,8 @@ in {
       extraGroups = [
         "docker" # Allow access to the docker socket.
       ];
-      openssh.authorizedKeys.keys = [
+      openssh.authorizedKeys.keyFiles = [
-        # Hugo
+        config.sops.secrets.user_keys_backup.path
-        "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICms6vjhE9kOlqV5GBPGInwUHAfCSVHLI2Gtzee0VXPh"
       ];
     };
   };

users/deploy/default.nix

@@ -3,7 +3,19 @@
 let
   cfg = config.homelab.users.deploy;
 in {
-  options.homelab.users.deploy.enable = lib.mkEnableOption "user Deploy";
+  options.homelab.users.deploy = {
+    enable = lib.mkEnableOption "user Deploy";
+
+    authorizedKeys = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [];
+      description = ''
+        Additional SSH public keys authorized for the deploy user.
+        The CI runner key should be provided as a base key; personal
+        workstation keys can be appended here per host or globally.
+      '';
+    };
+  };
 
   config = lib.mkIf cfg.enable {
     users = {
@@ -15,12 +27,15 @@ in {
         isSystemUser = true;
         home = "/var/empty";
         shell = pkgs.bashInteractive;
-        openssh.authorizedKeys.keys = [
+        openssh.authorizedKeys.keyFiles = [
-          "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPrG+ldRBdCeHEXrsy/qHXIJYg8xQXVuiUR0DxhFjYNg"
+          config.sops.secrets.user_keys_deploy.path
         ];
       };
     };
 
+    # Allow the deploy user to push closures to the nix store
+    nix.settings.trusted-users = [ "deploy" ];
+
     security.sudo.extraRules = [
       {
         groups = [