nixos: services: nextcloud: add fail2ban jail

modules/nixos/services/nextcloud/default.nix

@@ -87,5 +87,25 @@ in
         "${config.services.nextcloud.home}/data/appdata_*/preview"
       ];
     };
+
+    services.fail2ban.jails = {
+      nextcloud = ''
+        enabled = true
+        filter = nextcloud
+        port = http,https
+      '';
+    };
+
+    environment.etc = {
+      "fail2ban/filter.d/nextcloud.conf".text = ''
+        [Definition]
+        _groupsre = (?:(?:,?\s*"\w+":(?:"[^"]+"|\w+))*)
+        datepattern = ,?\s*"time"\s*:\s*"%%Y-%%m-%%d[T ]%%H:%%M:%%S(%%z)?"
+        failregex = ^[^{]*\{%(_groupsre)s,?\s*"remoteAddr":"<HOST>"%(_groupsre)s,?\s*"message":"Login failed:
+                    ^[^{]*\{%(_groupsre)s,?\s*"remoteAddr":"<HOST>"%(_groupsre)s,?\s*"message":"Trusted domain error.
+                    ^[^{]*\{%(_groupsre)s,?\s*"remoteAddr":"<HOST>"%(_groupsre)s,?\s*"message":"Two-factor challenge failed:
+        journalmatch = _SYSTEMD_UNIT=phpfpm-nextcloud.service
+      '';
+    };
   };
 }