clanModule: Extend dyndns support for most dns hosters. Improve security.

clanModules/dyndns/default.nix

@@ -14,18 +14,31 @@ let
   secret_path =
     opt: config.clan.core.facts.services."${secret_id opt}".secret."${secret_id opt}".path;
 
+  # We check that a secret has not been set in extraSettings.
+  extraSettingsSafe =
+    opt:
+    if (builtins.hasAttr opt.secret_field_name opt.extraSettings) then
+      throw "Please do not set ${opt.secret_field_name} in extraSettings, it is automatically set by the dyndns module."
+    else
+      opt.extraSettings;
   /*
     We go from:
-    {home.gchq.icu:{value:{domain:gchq.icu,host:home, provider:namecheap}}}
+    {home.example.com:{value:{domain:example.com,host:home, provider:namecheap}}}
     To:
-    {settings: [{domain: gchq.icu, host: home, provider: namecheap, password: dyndns-namecheap-gchq.icu}]}
+    {settings: [{domain: example.com, host: home, provider: namecheap, password: dyndns-namecheap-example.com}]}
   */
   service_config = {
     settings = builtins.catAttrs "value" (
       builtins.attrValues (
         lib.mapAttrs (_: opt: {
-          value = opt // {
-            password = secret_id opt;
+          value =
+            (extraSettingsSafe opt)
+            // {
+              domain = opt.domain;
+              provider = opt.provider;
+            }
+            // {
+              "${opt.secret_field_name}" = secret_id opt;
             };
         }) cfg.settings
       )
@@ -57,6 +70,25 @@ in
       description = "Group to run the service as";
     };
 
+    server = {
+      enable = lib.mkEnableOption "dyndns webserver";
+      domain = lib.mkOption {
+        type = lib.types.str;
+        description = "Domain to serve the webservice on";
+      };
+      port = lib.mkOption {
+        type = lib.types.int;
+        default = 54805;
+        description = "Port to listen on";
+      };
+    };
+
+    period = lib.mkOption {
+      type = lib.types.int;
+      default = 5;
+      description = "Domain update period in minutes";
+    };
+
     settings = lib.mkOption {
       type = lib.types.attrsOf (
         lib.types.submodule (
@@ -64,24 +96,44 @@ in
           {
             options = {
               provider = lib.mkOption {
+                example = "namecheap";
                 type = lib.types.str;
                 description = "The dyndns provider to use";
               };
               domain = lib.mkOption {
                 type = lib.types.str;
-                description = "The top level domain to update. For example 'example.com'.
-              If you want to update a subdomain, add the 'subdomain' option";
+                example = "example.com";
+                description = "The top level domain to update.";
               };
-              host = lib.mkOption {
-                type = lib.types.nullOr lib.types.str;
-                description = "The subdomain to update of the tld";
+              secret_field_name = lib.mkOption {
+                example = [
+                  "password"
+                  "api_key"
+                ];
+                type = lib.types.enum [
+                  "password"
+                  "token"
+                  "api_key"
+                ];
+                default = "password";
+                description = "The field name for the secret";
+              };
+              # TODO: Ideally we would create a gigantic list of all possible settings / types
+              # optimally we would have a way to generate the options from the source code
+              extraSettings = lib.mkOption {
+                type = lib.types.attrsOf lib.types.str;
+                default = { };
+                description = ''
+                  Extra settings for the provider.
+                  Provider specific settings: https://github.com/qdm12/ddns-updater#configuration
+                '';
               };
             };
           }
         )
       );
       default = [ ];
-      description = "Wifi networks to predefine";
+      description = "Configuration for which domains to update";
     };
   };
 
@@ -106,6 +158,24 @@ in
         createHome = true;
       };
 
+      networking.firewall.allowedTCPPorts = lib.mkIf cfg.server.enable [
+        80
+        443
+      ];
+
+      services.nginx = lib.mkIf cfg.server.enable {
+        enable = true;
+        virtualHosts = {
+          "${cfg.server.domain}" = {
+            forceSSL = true;
+            enableACME = true;
+            locations."/" = {
+              proxyPass = "http://localhost:${toString cfg.server.port}";
+            };
+          };
+        };
+      };
+
       systemd.services.${name} = {
         path = [ ];
         description = "Dynamic DNS updater";
@@ -113,6 +183,9 @@ in
         wantedBy = [ "multi-user.target" ];
         environment = {
           MYCONFIG = "${builtins.toJSON service_config}";
+          SERVER_ENABLED = if cfg.server.enable then "yes" else "no";
+          PERIOD = "${toString cfg.period}m";
+          LISTENING_ADDRESS = ":${toString cfg.server.port}";
         };
 
         serviceConfig =
@@ -135,7 +208,14 @@ in
               config = json.loads(config_str)
               print(f"Config: {config}")
               for attrset in config["settings"]:
+                  if "password" in attrset:
                       attrset['password'] = get_credential(attrset['password'])
+                  elif "token" in attrset:
+                      attrset['token'] = get_credential(attrset['token'])
+                  elif "api_key" in attrset:
+                      attrset['api_key'] = get_credential(attrset['api_key'])
+                  else:
+                      raise ValueError(f"Missing secret field in {attrset}")
 
               # create directory data if it does not exist
               data_dir = Path('data')
@@ -162,7 +242,19 @@ in
             LoadCredential = lib.mapAttrsToList (_: opt: "${secret_id opt}:${secret_path opt}") cfg.settings;
             User = cfg.user;
             Group = cfg.group;
+            NoNewPrivileges = true;
+            PrivateTmp = true;
+            ProtectSystem = "strict";
+            ReadOnlyPaths = "/";
+            PrivateDevices = "yes";
+            ProtectKernelModules = "yes";
+            ProtectKernelTunables = "yes";
+
             WorkingDirectory = "/var/lib/${name}";
+            ReadWritePaths = [
+              "/proc/self"
+              "/var/lib/${name}"
+            ];
 
             Restart = "always";
             RestartSec = 60;

clanModules/matrix-synapse/default.nix

@@ -169,6 +169,11 @@ in
         ];
       };
 
+    networking.firewall.allowedTCPPorts = [
+      80
+      443
+    ];
+
     services.nginx = {
       enable = true;
       virtualHosts = {