Add rspamd, ClamAV and sentinel Valkey to the mail namespace (#542)

The smarthost routes all mail through one rspamd: inbound that survived the edge gets the AI (LiteLLM Haiku) pass and is tagged for Stalwart's Junk filing; outbound from the lab and pods is DKIM-signed.

- add rspamd (milter via ClusterIP only), ClamAV and a 3-node sentinel Valkey
- tag inbound (`X-Spam`, `X-Spam-Status`, `X-Spamd-Result`), reject only viruses, tempfail when ClamAV fails
- score inbound against the hop before the edge relays (`external_relay`)
- DKIM-sign and skip GPT only for the smarthost's mynetworks sources
- elect the highest-offset Valkey on full restart; RDB, 384mb `volatile-ttl`
- read a hashed controller password (`password_hash`)

Requires `password_hash` in kv `mail/default/rspamd-controller`.

Reviewed-on: #542
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

apps/base/mail/rspamd/actions.conf

@@ -0,0 +1,3 @@
+reject = 15;
+add_header = 6;
+greylist = null;

apps/base/mail/rspamd/antivirus.conf

@@ -0,0 +1,8 @@
+clamav {
+  type = "clamav";
+  servers = "clamav.mail.svc.cluster.local:3310";
+  symbol = "CLAM_VIRUS";
+  action = "reject";
+  scan_mime_parts = true;
+  log_clean = false;
+}

apps/base/mail/rspamd/dkim_signing.conf

@@ -0,0 +1,7 @@
+sign_authenticated = false;
+sign_local = true;
+sign_inbound = false;
+use_domain = "header";
+allow_hdrfrom_mismatch = false;
+selector = "mail";
+path = "/etc/rspamd/dkim/$domain.$selector.key";

apps/base/mail/rspamd/external_relay.conf

@@ -0,0 +1,8 @@
+# Edge gateway public IPs (smarthost gateways.cidr): score the first hop before them.
+enabled = true;
+rules {
+  EDGE_RELAY {
+    strategy = "ip_map";
+    ip_map = ["192.0.2.1/32", "192.0.2.2/32"];
+  }
+}

apps/base/mail/rspamd/force_actions.conf

@@ -0,0 +1,7 @@
+rules {
+  CLAMAV_UNAVAILABLE {
+    action = "soft reject";
+    expression = "CLAM_VIRUS_FAIL";
+    message = "Virus scanner unavailable, try again later";
+  }
+}

apps/base/mail/rspamd/gpt.conf

@@ -0,0 +1,22 @@
+enabled = true;
+type = "openai";
+url = "http://litellm.litellm.svc.cluster.local:4000/v1/chat/completions";
+api_key = "{= env.LITELLM_API_KEY =}";
+model = "claude-haiku-4-5";
+model_parameters = {
+  "claude-haiku-4-5" = {
+    max_tokens = 400,
+    temperature = 0.0,
+  }
+};
+timeout = 10s;
+# Inbound only (settings.conf disables it outbound); only uncertain scores (2 <= score < 12).
+condition = <<EOD
+return function(task)
+  local res = task:get_metric_result()
+  if not res then return false, 'no result' end
+  if res.passthrough then return false, 'passthrough' end
+  if res.score < 2 or res.score >= 12 then return false, 'score not uncertain' end
+  return true
+end
+EOD

apps/base/mail/rspamd/greylist.conf

@@ -0,0 +1 @@
+enabled = false;

apps/base/mail/rspamd/history_redis.conf

@@ -0,0 +1 @@
+nrows = 5000;

apps/base/mail/rspamd/local_networks.map

@@ -0,0 +1,30 @@
+# Outbound sources (smarthost mynetworks): DKIM-signed, scored with reject, no GPT.
+127.0.0.0/8
+::1
+10.42.0.0/16
+10.10.12.200/32
+198.18.1.10/32
+198.18.2.160/27
+198.18.2.192/27
+198.18.13.0/24
+198.18.14.0/24
+198.18.15.0/24
+198.18.16.0/24
+198.18.17.0/24
+198.18.18.0/24
+198.18.19.0/24
+198.18.20.0/24
+198.18.21.0/24
+198.18.22.0/24
+198.18.23.0/24
+198.18.25.0/24
+198.18.26.0/24
+198.18.27.0/24
+198.18.28.0/24
+198.18.29.0/24
+198.18.64.0/24
+198.18.65.0/24
+198.18.66.0/24
+198.18.67.0/24
+198.18.68.0/24
+198.18.69.0/24

apps/base/mail/rspamd/milter_headers.conf

@@ -0,0 +1,2 @@
+use = ["x-spamd-result", "x-spam-status", "x-spam-level", "authentication-results"];
+skip_local = true;

apps/base/mail/rspamd/options.inc

@@ -0,0 +1,2 @@
+local_addrs = "/etc/rspamd/local.d/local_networks.map";
+task_timeout = 20s;

apps/base/mail/rspamd/redis.conf

@@ -0,0 +1,4 @@
+sentinels = "rspamd-valkey-sentinel.mail.svc.cluster.local:26379";
+sentinel_masters_pattern = "^rspamd$";
+sentinel_watch_time = 10s;
+servers = "rspamd-valkey-0.rspamd-valkey.mail.svc.cluster.local.:6379";

apps/base/mail/rspamd/settings.conf

@@ -0,0 +1,19 @@
+outbound {
+  priority = high;
+  ip_map = "/etc/rspamd/local.d/local_networks.map";
+  apply {
+    symbols_disabled = ["GPT_CHECK"];
+  }
+}
+inbound {
+  priority = high;
+  ip_map = "/etc/rspamd/local.d/local_networks.map";
+  inverse = true;
+  apply {
+    symbols_disabled = ["DKIM_SIGNED"];
+    # Tag only; reject stays defined (unreachable by score) so ClamAV's virus reject still applies.
+    actions {
+      reject = 1000;
+    }
+  }
+}

apps/base/mail/rspamd/spamassassin.conf

@@ -0,0 +1 @@
+ruleset = "/etc/rspamd/sa-rules/*.cf";

apps/base/mail/rspamd/worker-controller.inc

@@ -0,0 +1,3 @@
+password = "{= env.CONTROLLER_PASSWORD_HASH =}";
+enable_password = "{= env.CONTROLLER_PASSWORD_HASH =}";
+allow_file_and_shm_inputs = false;

apps/base/mail/rspamd/worker-normal.inc

@@ -0,0 +1,2 @@
+count = 2;
+allow_file_and_shm_inputs = false;

apps/base/mail/rspamd/worker-proxy.inc

@@ -0,0 +1 @@
+allow_file_and_shm_inputs = false;