[Web][Postfix] Add mail policies: per-recipient send/receive rules for mailboxes and groups

data/conf/postfix/main.cf

@@ -50,6 +50,7 @@ postscreen_greet_wait = 3s
 postscreen_non_smtp_command_enable = no
 postscreen_pipelining_enable = no
 proxy_read_maps = proxy:mysql:/opt/postfix/conf/sql/mysql_sasl_passwd_maps_transport_maps.cf,
+  proxy:mysql:/opt/postfix/conf/sql/mysql_mail_policy_maps.cf,
   proxy:mysql:/opt/postfix/conf/sql/mysql_mbr_access_maps.cf,
   proxy:mysql:/opt/postfix/conf/sql/mysql_tls_enforce_in_policy.cf,
   $sender_dependent_default_transport_maps,
@@ -90,6 +91,7 @@ smtpd_hard_error_limit = ${stress?1}${stress:5}
 smtpd_helo_required = yes
 smtpd_proxy_timeout = 600s
 smtpd_recipient_restrictions = check_recipient_mx_access proxy:mysql:/opt/postfix/conf/sql/mysql_mbr_access_maps.cf,
+  check_recipient_access proxy:mysql:/opt/postfix/conf/sql/mysql_mail_policy_maps.cf,
   permit_sasl_authenticated,
   permit_mynetworks,
   check_recipient_access proxy:mysql:/opt/postfix/conf/sql/mysql_tls_enforce_in_policy.cf,
@@ -170,5 +172,11 @@ parent_domain_matches_subdomains = debug_peer_list,fast_flush_domains,mynetworks
 # This Option is added to correctly set the X-Original-To Header when mails are send to lmtp (dovecot)
 lmtp_destination_recipient_limit=1
 
+# Mail policies: while policies or internal aliases exist, mysql_mail_policy_maps.cf returns this class and smtpd
+# asks the policy service for every recipient (mailcow-policy in master.cf); no answer defers the recipient
+smtpd_restriction_classes = mailcow_mail_policy
+mailcow_mail_policy = check_policy_service { unix:private/mailcow-policy, timeout=10s, default_action=DEFER_IF_PERMIT }
+mailcow-policy_time_limit = 3600s
+
 # DO NOT EDIT ANYTHING BELOW #
 # Overrides #

data/conf/postfix/master.cf

@@ -117,6 +117,9 @@ smtp_sender_cleanup unix n - y - 0 cleanup
 127.0.0.1:10027 inet n n n - 0 spawn user=nobody argv=/usr/local/bin/whitelist_forwardinghosts.sh
 # end whitelist_fwd
 
+# mail policies: policy service of smtpd, asks the mailcow UI (mailcow_mail_policy in main.cf)
+mailcow-policy unix - n n - 0 spawn user=nobody argv=/usr/local/bin/mailcow-policy.py
+
 # start watchdog-specific
 # logs to local7 (hidden)
 589 inet n      -       n       -       -       smtpd

data/conf/rspamd/dynmaps/mailpolicy.php

@@ -0,0 +1,39 @@
+<?php
+// Mail policy check for one recipient, asked by the Postfix policy service (mailcow-policy in master.cf)
+// Request: POST with the attributes of the Postfix policy request; answer: the action (DUNNO or the rejection)
+header('Content-Type: text/plain');
+require_once "vars.inc.php";
+require_once __DIR__ . '/../web/inc/lib/vendor/autoload.php';
+// Do not show errors, we log to using error_log
+ini_set('error_reporting', 0);
+// Init database
+$dsn = $database_type . ":unix_socket=" . $database_sock . ";dbname=" . $database_name;
+$opt = [
+    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
+    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+    PDO::ATTR_EMULATE_PREPARES   => false,
+];
+try {
+  $pdo = new PDO($dsn, $database_user, $database_pass, $opt);
+}
+catch (PDOException $e) {
+  error_log("MAILPOLICY: " . $e . PHP_EOL);
+  http_response_code(501);
+  exit;
+}
+
+if (!isset($_POST['request']) || $_POST['request'] !== 'smtpd_access_policy') {
+  http_response_code(400);
+  exit;
+}
+$value = fn(string $key): string => is_string($_POST[$key] ?? null) ? $_POST[$key] : '';
+
+try {
+  $policy = \Mailcow\MailPolicy\MailPolicyModule::create($pdo, \Mailcow\Core\Context::system());
+  echo $policy->api->check($value('sender'), $value('recipient'), $value('sasl_username'), (int)$value('server_port'));
+}
+catch (Throwable $e) {
+  // the policy service answers with a temporary error
+  error_log("MAILPOLICY: " . $e->getMessage() . PHP_EOL);
+  http_response_code(500);
+}

data/conf/rspamd/dynmaps/settings.php

@@ -469,35 +469,5 @@ while ($row = array_shift($rows)) {
 }
 ?>
 
-<?php
-// Start internal aliases
-
-$stmt = $pdo->query("SELECT `id`, `address`, `domain` FROM `alias` WHERE `active` = '1' AND `internal` = '1'");
-$aliases = $stmt->fetchAll(PDO::FETCH_ASSOC);
-while ($alias = array_shift($aliases)) {
-  // build allowed_domains regex and add target domain and alias domains
-  $stmt = $pdo->prepare("SELECT `alias_domain` FROM `alias_domain` WHERE `active` = '1' AND `target_domain` = :target_domain");
-  $stmt->execute(array(':target_domain' => $alias['domain']));
-  $allowed_domains = $stmt->fetchAll(PDO::FETCH_ASSOC);
-  $allowed_domains = array_map(function($item) {
-    return str_replace('.', '\.', $item['alias_domain']);
-  }, $allowed_domains);
-  $allowed_domains[] = str_replace('.', '\.', $alias['domain']);
-  $allowed_domains = implode('|', $allowed_domains);
-?>
-  internal_alias_<?=$alias['id'];?> {
-    priority = 10;
-    rcpt = "<?=$alias['address'];?>";
-    from = "/^((?!.*@(<?=$allowed_domains;?>)).)*$/";
-    apply "default" {
-      MAILCOW_INTERNAL_ALIAS = 9999.0;
-    }
-    symbols [
-      "MAILCOW_INTERNAL_ALIAS"
-    ]
-  }
-<?php
-}
-?>
 
 }