[Web][Postfix][Dovecot] Mail policies: compare addresses like Postfix, close bypasses via alias forms, temporary aliases, Sieve and cross-domain groups

data/Dockerfiles/postfix/Dockerfile

@@ -26,6 +26,7 @@ RUN groupadd -g 102 postfix \
 	postfix \
 	postfix-mysql \
 	postfix-pcre \
+	python3 \
 	redis-tools \
 	sasl2-bin \
 	sudo \
@@ -46,6 +47,7 @@ COPY postfix.sh /opt/postfix.sh
 COPY rspamd-pipe-ham /usr/local/bin/rspamd-pipe-ham
 COPY rspamd-pipe-spam /usr/local/bin/rspamd-pipe-spam
 COPY whitelist_forwardinghosts.sh /usr/local/bin/whitelist_forwardinghosts.sh
+COPY mailcow-policy.py /usr/local/bin/mailcow-policy.py
 COPY stop-supervisor.sh /usr/local/sbin/stop-supervisor.sh
 COPY docker-entrypoint.sh /docker-entrypoint.sh
 
@@ -53,6 +55,7 @@ RUN chmod +x /opt/postfix.sh \
   /usr/local/bin/rspamd-pipe-ham \
   /usr/local/bin/rspamd-pipe-spam \
   /usr/local/bin/whitelist_forwardinghosts.sh \
+  /usr/local/bin/mailcow-policy.py \
   /usr/local/sbin/stop-supervisor.sh
 RUN rm -rf /tmp/* /var/tmp/*
 

data/Dockerfiles/postfix/mailcow-policy.py

@@ -0,0 +1,54 @@
+#!/usr/bin/python3
+# Policy service of the mail policies (mailcow-policy in master.cf, spawned by Postfix): reads the policy requests
+# of smtpd and asks the mailcow UI for the action (nginx:8081/mailpolicy.php). Without an answer the recipient is
+# deferred; smtpd only asks while policies or internal aliases exist (mysql_mail_policy_maps.cf).
+
+import http.client
+import re
+import socket
+import sys
+from urllib.parse import urlencode
+
+# one line: DUNNO or a rejection with code and text
+valid_action = re.compile(rb'DUNNO|[45]\d\d [45]\.\d{1,3}\.\d{1,3} [\x20-\x7e]{1,200}')
+unavailable = b'DEFER_IF_PERMIT Mail policy check temporarily unavailable'
+# address of nginx, resolved once per process (a lookup costs more than the check)
+nginx = None
+
+def check(request):
+  global nginx
+  body = urlencode(sorted(request.items())).encode()
+  try:
+    if nginx is None:
+      nginx = socket.gethostbyname('nginx')
+    # http.client sets TCP_NODELAY, so the body is not held back until the headers are acknowledged
+    # below the timeout of Postfix (main.cf), so an answer always arrives
+    conn = http.client.HTTPConnection(nginx, 8081, timeout=8)
+    try:
+      conn.request('POST', '/mailpolicy.php', body, {'Host': 'nginx', 'Content-Type': 'application/x-www-form-urlencoded'})
+      response = conn.getresponse()
+      action = response.read()
+    finally:
+      conn.close()
+  except (OSError, http.client.HTTPException):
+    # nginx may have a new address after a restart
+    nginx = None
+    return unavailable
+  return action if response.status == 200 and valid_action.fullmatch(action) else unavailable
+
+def main():
+  request = {}
+  # attributes as bytes: addresses may contain any 8-bit characters
+  for line in sys.stdin.buffer:
+    line = line.rstrip(b'\r\n')
+    if line:
+      name, separator, value = line.partition(b'=')
+      if separator:
+        request[name] = value
+      continue
+    sys.stdout.buffer.write(b'action=' + check(request) + b'\n\n')
+    sys.stdout.buffer.flush()
+    request = {}
+
+if __name__ == '__main__':
+  main()

data/Dockerfiles/postfix/postfix.sh

@@ -15,6 +15,21 @@ until dig +short mailcow.email > /dev/null; do
   sleep 1
 done
 
+# Wait for updated schema (DB_VERSION from docker-compose.yml), the maps read tables the init_db of php-fpm creates on updates
+DBV_NOW=$(mariadb --ssl=false --socket=/var/run/mysqld/mysqld.sock -u ${DBUSER} -p${DBPASS} ${DBNAME} -e "SELECT version FROM versions WHERE application = 'db_schema';" -BN 2>/dev/null)
+DBV_WAIT=0
+while [[ "${DBV_NOW}" != "${DB_VERSION}" ]] && [[ ${DBV_WAIT} -lt 60 ]]; do
+  echo "Waiting for schema update..."
+  sleep 5
+  DBV_WAIT=$((DBV_WAIT + 1))
+  DBV_NOW=$(mariadb --ssl=false --socket=/var/run/mysqld/mysqld.sock -u ${DBUSER} -p${DBPASS} ${DBNAME} -e "SELECT version FROM versions WHERE application = 'db_schema';" -BN 2>/dev/null)
+done
+if [[ "${DBV_NOW}" != "${DB_VERSION}" ]]; then
+  echo -e "\e[31mDB schema is ${DBV_NOW}, expected ${DB_VERSION} - starting anyway, check the php-fpm log (init_db)\e[0m"
+else
+  echo "DB schema is ${DBV_NOW}"
+fi
+
 cat <<EOF > /etc/aliases
 # Autogenerated by mailcow
 null: /dev/null
@@ -224,6 +239,19 @@ query = SELECT CONCAT_WS(':', username, password) AS auth_data FROM transports
   LIMIT 1;
 EOF
 
+# Mail policies: while policies or internal aliases exist, smtpd asks the policy service (mailcow_mail_policy in main.cf)
+cat <<EOF > /opt/postfix/conf/sql/mysql_mail_policy_maps.cf
+# Autogenerated by mailcow
+user = ${DBUSER}
+password = ${DBPASS}
+hosts = unix:/var/run/mysqld/mysqld.sock
+dbname = ${DBNAME}
+query = SELECT 'mailcow_mail_policy' FROM DUAL WHERE '%s' != ''
+  AND (EXISTS (SELECT 1 FROM mail_policy_member JOIN mail_policy ON mail_policy.id = mail_policy_member.policy_id
+      WHERE mail_policy.active = '1')
+    OR EXISTS (SELECT 1 FROM alias WHERE internal = '1' AND active IN ('1', '2')));
+EOF
+
 cat <<EOF > /opt/postfix/conf/sql/mysql_virtual_alias_domain_maps.cf
 # Autogenerated by mailcow
 user = ${DBUSER}

data/conf/dovecot/dovecot.conf

@@ -199,6 +199,8 @@ plugin {
   sieve_plugins = sieve_imapsieve sieve_extprograms
   sieve_vacation_send_from_recipient = yes
   sieve_redirect_envelope_from = recipient
+  # Notifications are sent with the address of the mailbox (not :from or postmaster), so mail policies apply
+  sieve_notify_mailto_envelope_from = recipient
   # From elsewhere to Spam folder
   imapsieve_mailbox1_name = Junk
   imapsieve_mailbox1_causes = COPY

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, try_limit=1, 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'), $value('helo_name'));
+}
+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
-}
-?>
 
 }

data/web/admin/mailbox.php

@@ -11,6 +11,7 @@ $_SESSION['return_to'] = $_SERVER['REQUEST_URI'];
 
 $js_minifier->add('/web/js/site/imapsync.js');
 $js_minifier->add('/web/js/site/groups.js');
+$js_minifier->add('/web/js/site/mail-policy.js');
 $js_minifier->add('/web/js/site/mailbox.js');
 $js_minifier->add('/web/js/presets/sieveMailbox.js');
 $js_minifier->add('/web/js/site/pwgen.js');
@@ -46,6 +47,7 @@ $template_data = [
   'lang_edit' => json_encode($lang['edit']),
   'lang_datatables' => json_encode($lang['datatables']),
   'imapsync_redirect_uri' => \Mailcow\Imapsync\ImapsyncModule::fromGlobals()->oauth->redirectUri(),
+  'mail_policy_groups' => \Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->policies->groupChoices($domains),
 ];
 
 require_once $_SERVER['DOCUMENT_ROOT'] . '/inc/footer.inc.php';

data/web/api/openapi.yaml

@@ -1365,7 +1365,7 @@ paths:
                   description: show the group address as SOGo identity (needs sender_allowed)
                   type: boolean
                 internal:
-                  description: only accept mail from senders of the domain
+                  description: only accept mail from logged-in senders of the domain
                   type: boolean
                 template_id:
                   description: mailbox template applied to the members (admin only), empty = none
@@ -1377,6 +1377,115 @@ paths:
                   type: boolean
               type: object
       summary: Create group
+  /api/v1/add/mail-policy:
+    post:
+      responses:
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "200":
+          content:
+            application/json:
+              examples:
+                response:
+                  value:
+                    - log:
+                        - mail_policy
+                        - add
+                        - policy
+                        - domain: example.org
+                          name: Trainees
+                          send_mode: internal
+                          groups:
+                            - "7"
+                      msg:
+                        - mail_policy_added
+                        - Trainees
+                      type: success
+              schema:
+                properties:
+                  log:
+                    description: contains request object
+                    items: {}
+                    type: array
+                  msg:
+                    items: {}
+                    type: array
+                  type:
+                    enum:
+                      - success
+                      - danger
+                      - warning
+                      - error
+                    type: string
+                type: object
+          description: OK
+          headers: {}
+      tags:
+        - Mail policies
+      description: >-
+        Create a mail policy (admins; domain admins with the "mail_policies"
+        ACL for their domains). Postfix checks the policies for every
+        recipient: every policy of the sending mailbox and of the addressed
+        mailbox or group must allow the mail, otherwise the recipient is
+        refused with 550 5.7.1.
+      operationId: Create mail policy
+      requestBody:
+        content:
+          application/json:
+            schema:
+              example:
+                domain: example.org
+                name: Trainees
+                send_mode: internal
+                send_allow:
+                  - partner.example
+                receive_mode: all
+                receive_block:
+                  - group:8
+                groups:
+                  - "7"
+                active: "1"
+              properties:
+                domain:
+                  description: domain of the policy (required)
+                  type: string
+                name:
+                  description: unique per domain, max. 100 characters
+                  type: string
+                description:
+                  description: max. 255 characters
+                  type: string
+                send_mode:
+                  description: all; internal = recipients in the domain of the policy and its alias domains plus send_allow; list = send_allow only
+                  type: string
+                send_allow:
+                  description: addresses, domains or group:<id> of a group of the policy's domain (array or list separated by commas, spaces or newlines), max. 500
+                  type: array
+                send_block:
+                  description: recipients that are always refused, entries as send_allow
+                  type: array
+                receive_mode:
+                  description: all; internal = senders logged in with a mailbox of the domain plus receive_allow; list = receive_allow only
+                  type: string
+                receive_allow:
+                  description: entries as send_allow; addresses and domains of this mailcow count for logged-in senders only
+                  type: array
+                receive_block:
+                  description: senders that are always refused, entries as receive_allow
+                  type: array
+                reject_text:
+                  description: text of the 550 5.7.1 rejection, printable ASCII, max. 200 characters, empty = default text
+                  type: string
+                mailboxes:
+                  description: mailboxes of the domain the policy applies to (replaces the list), max. 500
+                  type: array
+                groups:
+                  description: group IDs of the domain the policy applies to (its members of that domain and mail to the group address), max. 500; domain admins need the mailbox_groups ACL, without it group IDs and group entries stay unchanged
+                  type: array
+                active:
+                  type: boolean
+              type: object
+      summary: Create mail policy
   /api/v1/add/oauth2-client:
     post:
       responses:
@@ -2853,6 +2962,62 @@ paths:
                   type: object
               type: object
       summary: Delete groups
+  /api/v1/delete/mail-policy:
+    post:
+      responses:
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "200":
+          content:
+            application/json:
+              examples:
+                response:
+                  value:
+                    - log:
+                        - mail_policy
+                        - delete
+                        - policy
+                        - id:
+                            - "3"
+                      msg:
+                        - mail_policy_removed
+                        - Trainees
+                      type: success
+              schema:
+                properties:
+                  log:
+                    description: contains request object
+                    items: {}
+                    type: array
+                  msg:
+                    items: {}
+                    type: array
+                  type:
+                    enum:
+                      - success
+                      - danger
+                      - warning
+                      - error
+                    type: string
+                type: object
+          description: OK
+          headers: {}
+      tags:
+        - Mail policies
+      description: Delete mail policies by ID.
+      operationId: Delete mail policies
+      requestBody:
+        content:
+          application/json:
+            schema:
+              example:
+                - "3"
+              properties:
+                items:
+                  description: contains list of policy IDs you want to delete
+                  type: object
+              type: object
+      summary: Delete mail policies
   /api/v1/delete/identity-link:
     post:
       responses:
@@ -4422,7 +4587,7 @@ paths:
                       description: show the group address as SOGo identity (needs sender_allowed)
                       type: boolean
                     internal:
-                      description: only accept mail from senders of the domain
+                      description: only accept mail from logged-in senders of the domain
                       type: boolean
                     template_id:
                       description: mailbox template applied to the members (admin only), empty = none
@@ -4497,6 +4662,106 @@ paths:
                   type: object
               type: object
       summary: Update groups
+  /api/v1/edit/mail-policy:
+    post:
+      responses:
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "200":
+          content:
+            application/json:
+              examples:
+                response:
+                  value:
+                    - log:
+                        - mail_policy
+                        - edit
+                        - policy
+                        - id:
+                            - "3"
+                          receive_mode: internal
+                      msg:
+                        - mail_policy_modified
+                        - Trainees
+                      type: success
+              schema:
+                properties:
+                  log:
+                    description: contains request object
+                    items: {}
+                    type: array
+                  msg:
+                    items: {}
+                    type: array
+                  type:
+                    enum:
+                      - success
+                      - danger
+                      - warning
+                      - error
+                    type: string
+                type: object
+          description: OK
+          headers: {}
+      tags:
+        - Mail policies
+      description: >-
+        Update mail policies. Attributes you do not send keep their value. The
+        domain cannot be changed.
+      operationId: Update mail policies
+      requestBody:
+        content:
+          application/json:
+            schema:
+              example:
+                items:
+                  - "3"
+                attr:
+                  receive_mode: internal
+              properties:
+                attr:
+                  properties:
+                    name:
+                      description: unique per domain, max. 100 characters
+                      type: string
+                    description:
+                      description: max. 255 characters
+                      type: string
+                    send_mode:
+                      description: all; internal = recipients in the domain of the policy and its alias domains plus send_allow; list = send_allow only
+                      type: string
+                    send_allow:
+                      description: addresses, domains or group:<id> of a group of the policy's domain (array or list separated by commas, spaces or newlines), max. 500
+                      type: array
+                    send_block:
+                      description: recipients that are always refused, entries as send_allow
+                      type: array
+                    receive_mode:
+                      description: all; internal = senders logged in with a mailbox of the domain plus receive_allow; list = receive_allow only
+                      type: string
+                    receive_allow:
+                      description: entries as send_allow; addresses and domains of this mailcow count for logged-in senders only
+                      type: array
+                    receive_block:
+                      description: senders that are always refused, entries as receive_allow
+                      type: array
+                    reject_text:
+                      description: text of the 550 5.7.1 rejection, printable ASCII, max. 200 characters, empty = default text
+                      type: string
+                    mailboxes:
+                      description: mailboxes of the domain the policy applies to (replaces the list), max. 500
+                      type: array
+                    groups:
+                      description: group IDs of the domain the policy applies to (its members of that domain and mail to the group address), max. 500; domain admins need the mailbox_groups ACL, without it group IDs and group entries stay unchanged
+                      type: array
+                    active:
+                      type: boolean
+                  type: object
+                items:
+                  description: contains list of policy IDs you want to update
+                  type: object
+              type: object
+      summary: Update mail policies
   /api/v1/edit/identity-provider-sync:
     post:
       responses:
@@ -6455,6 +6720,107 @@ paths:
         may send as through groups.
       operationId: Get group memberships
       summary: Get group memberships
+  "/api/v1/get/mail-policy/{id}":
+    get:
+      parameters:
+        - description: id of the policy, or "all" (optionally followed by /domain1,domain2)
+          example: all
+          in: path
+          name: id
+          required: true
+          schema:
+            type: string
+        - description: e.g. api-key-string
+          example: api-key-string
+          in: header
+          name: X-API-Key
+          required: false
+          schema:
+            type: string
+      responses:
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "200":
+          content:
+            application/json:
+              examples:
+                response:
+                  value:
+                    - id: 3
+                      domain: example.org
+                      name: Trainees
+                      description: Trainees only send internally
+                      send_mode: internal
+                      send_allow:
+                        - partner.example
+                      send_block: []
+                      receive_mode: all
+                      receive_allow: []
+                      receive_block:
+                        - group:8
+                      reject_text: ""
+                      active: 1
+                      mailboxes: []
+                      groups:
+                        - 7
+                      created: "2026-11-07 12:00:00"
+                      modified: null
+                      can_edit: 1
+          description: OK
+          headers: {}
+      tags:
+        - Mail policies
+      description: >-
+        Mail policies visible to the caller (admins all, domain admins with the
+        "mail_policies" ACL their domains).
+      operationId: Get mail policies
+      summary: Get mail policies
+  "/api/v1/get/mail-policy/test/{sender}/{recipient}":
+    get:
+      parameters:
+        - description: envelope sender, "-" for the null sender (bounces)
+          example: trainee@example.org
+          in: path
+          name: sender
+          required: true
+          schema:
+            type: string
+        - description: recipient; append /login to test a sender logged in with its mailbox
+          example: someone@external.example
+          in: path
+          name: recipient
+          required: true
+          schema:
+            type: string
+      responses:
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "200":
+          content:
+            application/json:
+              examples:
+                response:
+                  value:
+                    allowed: 0
+                    side: send
+                    policy: Trainees
+                    internal_alias: 0
+                    logged_in: 1
+                    text: Sending to this recipient is not allowed by the mail policy of the sender
+          description: OK
+          headers: {}
+      tags:
+        - Mail policies
+      description: >-
+        Would Postfix accept the mail for this recipient? side is "send",
+        "receive" or "address" (the recipient routes through another address),
+        policy is empty for a policy of another domain (its text is then the
+        default text), internal_alias = refused by the internal flag of an
+        alias or group. Domain admins test addresses of their domains; a sender
+        of another domain is tested as not logged in. Empty answer for invalid
+        input.
+      operationId: Test mail policies
+      summary: Test mail policies
   /api/v1/get/identity-provider/sync-status:
     get:
       responses:
@@ -8011,6 +8377,8 @@ tags:
     description: Manage API keys
   - name: Groups
     description: Mailbox groups (distribution lists, send-as rights, templates)
+  - name: Mail policies
+    description: Whom mailboxes and groups may send to and receive from
   - name: Routing
     description: Define your own email routes
   - name: Resources

data/web/domainadmin/mailbox.php

@@ -11,6 +11,7 @@ $_SESSION['return_to'] = $_SERVER['REQUEST_URI'];
 
 $js_minifier->add('/web/js/site/imapsync.js');
 $js_minifier->add('/web/js/site/groups.js');
+$js_minifier->add('/web/js/site/mail-policy.js');
 $js_minifier->add('/web/js/site/mailbox.js');
 $js_minifier->add('/web/js/presets/sieveMailbox.js');
 $js_minifier->add('/web/js/site/pwgen.js');
@@ -45,6 +46,7 @@ $template_data = [
   'lang_edit' => json_encode($lang['edit']),
   'lang_datatables' => json_encode($lang['datatables']),
   'imapsync_redirect_uri' => \Mailcow\Imapsync\ImapsyncModule::fromGlobals()->oauth->redirectUri(),
+  'mail_policy_groups' => \Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->policies->groupChoices($domains),
 ];
 
 require_once $_SERVER['DOCUMENT_ROOT'] . '/inc/footer.inc.php';

data/web/edit.php

@@ -115,6 +115,17 @@ if (isset($_SESSION['mailcow_cc_role'])) {
           'mbox_templates' => ($_SESSION['mailcow_cc_role'] == 'admin') ? mailbox('get', 'mailbox_templates') : [],
         ];
     }
+    elseif (isset($_GET['mail-policy']) &&
+      is_numeric($_GET['mail-policy'])) {
+        $mail_policy = \Mailcow\MailPolicy\MailPolicyModule::fromGlobals();
+        $result = $mail_policy->api->getPolicy($_GET['mail-policy']);
+        $template = 'edit/mail-policy.twig';
+        // Choices: mailboxes and groups of the domain of the policy
+        $template_data = [
+          'mailboxes' => !empty($result) ? mailbox('get', 'mailboxes', $result['domain']) : [],
+          'mail_policy_groups' => !empty($result) ? $mail_policy->policies->groupChoices([$result['domain']]) : [],
+        ];
+    }
     elseif (isset($_GET['api-key']) &&
       is_numeric($_GET['api-key'])) {
         $result = \Mailcow\ApiKey\ApiKeyModule::fromGlobals()->api->getKey($_GET['api-key']);

data/web/inc/footer.inc.php

@@ -74,6 +74,7 @@ $globalVariables = [
   'lang_danger' => json_encode($lang['danger']),
   'lang_syncjobs' => json_encode($lang['syncjobs']),
   'lang_groups' => json_encode($lang['groups']),
+  'lang_mail_policy' => json_encode($lang['mail_policy'] ?? []),
   'docker_timeout' => $DOCKER_TIMEOUT,
   'session_lifetime' => (int)$SESSION_LIFETIME,
   'csrf_token' => $_SESSION['CSRF']['TOKEN'],

data/web/inc/functions.mailbox.inc.php

@@ -2432,6 +2432,7 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
               if ($address != $is_now['address']) {
                 // Send-as grants of groups follow the address
                 \Mailcow\MailboxGroup\MailboxGroupModule::fromGlobals()->api->addressRenamed($is_now['address'], $address);
+                \Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->addressRenamed($is_now['address'], $address);
               }
             }
             $_SESSION['return'][] = array(
@@ -3295,7 +3296,8 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
               'mailbox_group_imap_grant' => ['owner'],
               'mailbox_group_sogo_grant' => ['owner'],
               'mailbox_group_sogo_acl' => ['c_uid'],
-              'mailbox_group_subscription' => ['username', 'owner']
+              'mailbox_group_subscription' => ['username', 'owner'],
+              'mail_policy_member' => ['username']
             ];
             foreach ($tables as $table => $columns) {
               foreach ($columns as $column) {
@@ -3311,6 +3313,8 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
             \Mailcow\Imapsync\ImapsyncModule::fromGlobals()->sources->onAccountRenamed($old_username, $new_username);
             // Group memberships and send-as grants follow, group aliases are rebuilt
             \Mailcow\MailboxGroup\MailboxGroupModule::fromGlobals()->hooks->onMailboxRenamed($old_username, $new_username);
+            // Address entries of mail policies follow
+            \Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->addressRenamed($old_username, $new_username);
 
             // Update c_uid, c_name and mail in _sogo_static_view table
             $pdo->prepare("UPDATE _sogo_static_view SET c_uid = :new_username, c_name = :new_username2, mail = :new_username3 WHERE c_uid = :old_username")

data/web/inc/init_db.inc.php

@@ -491,6 +491,86 @@ function init_db_schema()
         ),
         "attr" => "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC"
       ),
+      // Mail policies: whom the assigned mailboxes and groups may send to and receive from (Mailcow\MailPolicy)
+      "mail_policy" => array(
+        "cols" => array(
+          "id" => "INT NOT NULL AUTO_INCREMENT",
+          "domain" => "VARCHAR(255) NOT NULL",
+          "name" => "VARCHAR(100) NOT NULL",
+          "description" => "VARCHAR(255) NOT NULL DEFAULT ''",
+          // all, internal or list; the entries are JSON lists of addresses, domains and group:<id>
+          "send_mode" => "VARCHAR(16) NOT NULL DEFAULT 'all'",
+          "send_allow" => "MEDIUMTEXT NOT NULL",
+          "send_block" => "MEDIUMTEXT NOT NULL",
+          "receive_mode" => "VARCHAR(16) NOT NULL DEFAULT 'all'",
+          "receive_allow" => "MEDIUMTEXT NOT NULL",
+          "receive_block" => "MEDIUMTEXT NOT NULL",
+          "reject_text" => "VARCHAR(255) NOT NULL DEFAULT ''",
+          "created" => "DATETIME(0) NOT NULL DEFAULT NOW(0)",
+          "modified" => "DATETIME ON UPDATE CURRENT_TIMESTAMP",
+          "active" => "TINYINT(1) NOT NULL DEFAULT '1'"
+        ),
+        "keys" => array(
+          "primary" => array(
+            "" => array("id")
+          ),
+          "unique" => array(
+            "domain_name" => array("domain", "name")
+          ),
+          "fkey" => array(
+            "fk_mail_policy_domain" => array(
+              "col" => "domain",
+              "ref" => "domain.domain",
+              "delete" => "CASCADE",
+              "update" => "NO ACTION"
+            )
+          )
+        ),
+        "attr" => "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC"
+      ),
+      // a mailbox or a group (its members and its address) a policy is assigned to
+      "mail_policy_member" => array(
+        "cols" => array(
+          "id" => "INT NOT NULL AUTO_INCREMENT",
+          "policy_id" => "INT NOT NULL",
+          "username" => "VARCHAR(255) NULL DEFAULT NULL",
+          "group_id" => "INT NULL DEFAULT NULL"
+        ),
+        "keys" => array(
+          "primary" => array(
+            "" => array("id")
+          ),
+          "unique" => array(
+            "policy_mailbox" => array("policy_id", "username"),
+            "policy_group" => array("policy_id", "group_id")
+          ),
+          "key" => array(
+            "username" => array("username"),
+            "group_id" => array("group_id")
+          ),
+          "fkey" => array(
+            "fk_mail_policy_member_policy" => array(
+              "col" => "policy_id",
+              "ref" => "mail_policy.id",
+              "delete" => "CASCADE",
+              "update" => "NO ACTION"
+            ),
+            "fk_mail_policy_member_mailbox" => array(
+              "col" => "username",
+              "ref" => "mailbox.username",
+              "delete" => "CASCADE",
+              "update" => "NO ACTION"
+            ),
+            "fk_mail_policy_member_group" => array(
+              "col" => "group_id",
+              "ref" => "mailbox_group.id",
+              "delete" => "CASCADE",
+              "update" => "NO ACTION"
+            )
+          )
+        ),
+        "attr" => "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC"
+      ),
       "mailbox_group_imap_grant" => array(
         "cols" => array(
           "id" => "INT NOT NULL AUTO_INCREMENT",
@@ -703,7 +783,8 @@ function init_db_schema()
             "group_id" => array("group_id")
           ),
           "key" => array(
-            "domain" => array("domain")
+            "domain" => array("domain"),
+            "internal" => array("internal", "active")
           ),
           "fkey" => array(
             "fk_alias_mailbox_group" => array(
@@ -1053,7 +1134,8 @@ function init_db_schema()
           "domain_relayhost" => "TINYINT(1) NOT NULL DEFAULT '1'",
           "domain_desc" => "TINYINT(1) NOT NULL DEFAULT '0'",
           "alias_external_goto" => "TINYINT(1) NOT NULL DEFAULT '1'",
-          "mailbox_groups" => "TINYINT(1) NOT NULL DEFAULT '1'"
+          "mailbox_groups" => "TINYINT(1) NOT NULL DEFAULT '1'",
+          "mail_policies" => "TINYINT(1) NOT NULL DEFAULT '0'"
         ),
         "keys" => array(
           "primary" => array(

data/web/inc/lib/mailcow/MailPolicy/Controller/MailPolicyApiController.php

@@ -0,0 +1,132 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Controller;
+
+use Mailcow\Core\AccessDenied;
+use Mailcow\Core\ApiResponse;
+use Mailcow\Core\UserError;
+use Mailcow\MailPolicy\Service\PolicyEngine;
+use Mailcow\MailPolicy\Service\PolicyService;
+use PDOException;
+
+/**
+ * HTTP API adapter for json_api.php and edit.php (routes `mail-policy`), and the answer to the Postfix policy
+ * service (data/conf/rspamd/dynmaps/mailpolicy.php). Messages are logged as ['mail_policy', action, 'policy', data].
+ */
+class MailPolicyApiController
+{
+    public function __construct(private PolicyService $policies, private PolicyEngine $engine, private ApiResponse $response)
+    {
+    }
+
+    /** POST add/mail-policy */
+    public function addPolicy(array $attr): bool
+    {
+        return $this->handle('add', $attr, function (array $log) use ($attr): bool {
+            $policy = $this->policies->create($attr);
+            return $this->response->success(['mail_policy_added', htmlspecialchars($policy->name)], $log);
+        });
+    }
+
+    /** POST edit/mail-policy: one message per id */
+    public function editPolicies(?array $items, array $attr): bool
+    {
+        $data = array_merge(['id' => $items], $attr);
+        return $this->handle('edit', $data, function (array $log) use ($data, $attr): bool {
+            $this->policies->requireEditor();
+            return $this->batch((array)($data['id'] ?? []), $log,
+                fn(int $id): array => ['mail_policy_modified', htmlspecialchars($this->policies->update($id, $attr)->name)]);
+        });
+    }
+
+    /** POST delete/mail-policy: one message per id */
+    public function deletePolicies(array $items): bool
+    {
+        return $this->handle('delete', ['id' => $items], function (array $log) use ($items): bool {
+            $this->policies->requireEditor();
+            return $this->batch($items, $log, fn(int $id): array => ['mail_policy_removed', htmlspecialchars($this->policies->delete($id)->name)]);
+        });
+    }
+
+    /** GET mail-policy/all[/<domain,domain>] */
+    public function getPolicies(?string $domains = null): array
+    {
+        $list = array_values(array_filter(array_map('trim', explode(',', (string)$domains)), 'strlen'));
+        return array_values(array_filter(array_map(fn(int $id): array => $this->getPolicy($id), $this->policies->visibleIds($list))));
+    }
+
+    /** GET mail-policy/<id>, also edit.php */
+    public function getPolicy(mixed $id): array
+    {
+        $id = $this->toId($id);
+        $policy = ($id === null) ? null : $this->policies->get($id);
+        return ($policy === null) ? [] : $this->policies->toArray($policy);
+    }
+
+    /** GET mail-policy/test/<sender>/<recipient>[/login]: would the mail be accepted? Sender "-" = null sender; [] when not allowed to ask */
+    public function test(string $sender, string $recipient, bool $loggedIn): array
+    {
+        try {
+            return $this->policies->test(($sender === '-') ? '' : $sender, $recipient, $loggedIn);
+        } catch (UserError) {
+            return [];
+        }
+    }
+
+    /** functions.mailbox.inc.php: a mailbox or alias was renamed */
+    public function addressRenamed(string $old, string $new): void
+    {
+        $this->policies->addressRenamed($old, $new);
+    }
+
+    /** Answer for the Postfix policy service: DUNNO or the rejection */
+    public function check(string $sender, string $recipient, string $login, int $port, string $helo = ''): string
+    {
+        return $this->engine->check($sender, $recipient, $login, $port, $helo)->action();
+    }
+
+    /**
+     * Runs one write call: $work gets the log entry and returns the result for process_*_return().
+     * A UserError becomes a danger message, a database error stops the call with one `mysql_error` message.
+     */
+    private function handle(string $action, mixed $data, callable $work): bool
+    {
+        $log = ['mail_policy', $action, 'policy', $data];
+        try {
+            $result = $work($log);
+        } catch (UserError $e) {
+            $result = $this->response->error($e, $log);
+        } catch (PDOException $e) {
+            $result = $this->response->danger(['mysql_error', $e->getMessage()], $log);
+        }
+        $this->response->flush();
+        return $result;
+    }
+
+    /** One message per id: the success message returned by $work(id), or the UserError */
+    private function batch(array $ids, array $log, callable $work): bool
+    {
+        foreach ($ids as $id) {
+            try {
+                $this->response->success($work($this->requireId($id)), $log);
+            } catch (UserError $e) {
+                $this->response->error($e, $log);
+            }
+        }
+        return true;
+    }
+
+    /** Integer id from request input ("12", 12); null for anything else */
+    private function toId(mixed $id): ?int
+    {
+        return (is_numeric($id) && (float)$id == (int)(float)$id) ? (int)(float)$id : null;
+    }
+
+    /** @throws AccessDenied for ids that cannot exist */
+    private function requireId(mixed $id): int
+    {
+        return $this->toId($id) ?? throw new AccessDenied();
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/MailPolicyModule.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy;
+
+use Mailcow\Core\ApiResponse;
+use Mailcow\Core\Context;
+use Mailcow\MailPolicy\Controller\MailPolicyApiController;
+use Mailcow\MailPolicy\Repository\LookupRepository;
+use Mailcow\MailPolicy\Repository\PolicyRepository;
+use Mailcow\MailPolicy\Service\PolicyEngine;
+use Mailcow\MailPolicy\Service\PolicyService;
+use PDO;
+
+/**
+ * Composition root of the mail policies: whom mailboxes and groups may send to and receive from, checked by
+ * Postfix at RCPT TO through the policy service (mailcow-policy in master.cf, data/conf/rspamd/dynmaps/mailpolicy.php).
+ *
+ *   process_get_return(MailPolicyModule::fromGlobals()->api->getPolicies());
+ *   echo MailPolicyModule::create($pdo, Context::system())->api->check($sender, $recipient, $login, $port);  // policy service
+ */
+class MailPolicyModule
+{
+    public function __construct(
+        public readonly PolicyService $policies,
+        public readonly PolicyEngine $engine,
+        public readonly MailPolicyApiController $api
+    ) {
+    }
+
+    public static function create(PDO $pdo, Context $context): self
+    {
+        $engine = new PolicyEngine(new LookupRepository($pdo));
+        $policies = new PolicyService(new PolicyRepository($pdo), $engine, $context);
+        return new self($policies, $engine, new MailPolicyApiController($policies, $engine, new ApiResponse()));
+    }
+
+    /** Legacy entry point for procedural callers: reads $pdo and $_SESSION */
+    public static function fromGlobals(?Context $context = null): self
+    {
+        return self::create($GLOBALS['pdo'], $context ?? Context::fromSession($_SESSION ?? []));
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Model/Decision.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Model;
+
+/**
+ * Result of the policy check for one recipient: allowed, refused by the send or receive part of a policy, or refused
+ * because the recipient is written in a form the check cannot follow (routing through another address).
+ */
+class Decision
+{
+    private const TEXT = [
+        'send' => 'Sending to this recipient is not allowed by the mail policy of the sender',
+        'receive' => 'This recipient does not accept mail from this sender',
+        'address' => 'This form of the recipient address is not allowed by the mail policy',
+    ];
+
+    private function __construct(public readonly bool $allowed, public readonly string $side = '', public readonly ?Policy $policy = null)
+    {
+    }
+
+    public static function allow(): self
+    {
+        return new self(true);
+    }
+
+    /** $side send or receive; without $policy the default text is used */
+    public static function deny(string $side, ?Policy $policy = null): self
+    {
+        return new self(false, $side, $policy);
+    }
+
+    /** The recipient routes through another address (user%domain, domain!user, a second @) */
+    public static function routedAddress(): self
+    {
+        return new self(false, 'address');
+    }
+
+    /** Text of the rejection: the text of the policy or the default */
+    public function text(): string
+    {
+        return ($this->policy !== null && $this->policy->rejectText !== '') ? $this->policy->rejectText : self::defaultText($this->side);
+    }
+
+    public static function defaultText(string $side): string
+    {
+        return self::TEXT[$side] ?? '';
+    }
+
+    /** Answer for the Postfix policy protocol */
+    public function action(): string
+    {
+        return $this->allowed ? 'DUNNO' : '550 5.7.1 ' . $this->text();
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Model/Policy.php

@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Model;
+
+/**
+ * A mail policy (table `mail_policy`): whom its mailboxes and groups may send to and receive from.
+ *
+ * Each direction has a mode: `all` (only the blocked entries are refused), `internal` (the own domain and its
+ * alias domains, plus the allowed entries) or `list` (only the allowed entries). Blocked entries are always
+ * refused. Entries are addresses, domains or `group:<id>`. A sender counts as internal only when it is logged in
+ * to this mailcow (SASL) with a mailbox of the domain, never because of its address.
+ */
+class Policy
+{
+    public const MODES = ['all', 'internal', 'list'];
+
+    public ?int $id = null;
+    public string $domain = '';
+    public string $name = '';
+    public string $description = '';
+    public string $sendMode = 'all';
+    /** @var string[] */
+    public array $sendAllow = [];
+    /** @var string[] */
+    public array $sendBlock = [];
+    public string $receiveMode = 'all';
+    /** @var string[] */
+    public array $receiveAllow = [];
+    /** @var string[] */
+    public array $receiveBlock = [];
+    /** Text of the rejection, '' = default text */
+    public string $rejectText = '';
+    public int $active = 1;
+    /** @var string[] usernames the policy is assigned to */
+    public array $mailboxes = [];
+    /** @var int[] groups the policy is assigned to: their members and their address */
+    public array $groups = [];
+    public ?string $created = null;
+    public ?string $modified = null;
+
+    /** Row of `mail_policy`; assignments are set by the repository */
+    public static function fromRow(array $row): self
+    {
+        $policy = new self();
+        $policy->id = (int)$row['id'];
+        $policy->domain = (string)$row['domain'];
+        $policy->name = (string)$row['name'];
+        $policy->description = (string)($row['description'] ?? '');
+        $policy->sendMode = (string)$row['send_mode'];
+        $policy->sendAllow = self::list($row['send_allow'] ?? null);
+        $policy->sendBlock = self::list($row['send_block'] ?? null);
+        $policy->receiveMode = (string)$row['receive_mode'];
+        $policy->receiveAllow = self::list($row['receive_allow'] ?? null);
+        $policy->receiveBlock = self::list($row['receive_block'] ?? null);
+        $policy->rejectText = (string)($row['reject_text'] ?? '');
+        $policy->active = (int)$row['active'];
+        $policy->created = $row['created'] ?? null;
+        $policy->modified = $row['modified'] ?? null;
+        return $policy;
+    }
+
+    /** Column values for `mail_policy` */
+    public function toRow(): array
+    {
+        return [
+            'domain' => $this->domain,
+            'name' => $this->name,
+            'description' => $this->description,
+            'send_mode' => $this->sendMode,
+            'send_allow' => json_encode($this->sendAllow),
+            'send_block' => json_encode($this->sendBlock),
+            'receive_mode' => $this->receiveMode,
+            'receive_allow' => json_encode($this->receiveAllow),
+            'receive_block' => json_encode($this->receiveBlock),
+            'reject_text' => $this->rejectText,
+            'active' => $this->active,
+        ];
+    }
+
+    /** Entry of the API and the edit page */
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->id,
+            'domain' => $this->domain,
+            'name' => $this->name,
+            'description' => $this->description,
+            'send_mode' => $this->sendMode,
+            'send_allow' => $this->sendAllow,
+            'send_block' => $this->sendBlock,
+            'receive_mode' => $this->receiveMode,
+            'receive_allow' => $this->receiveAllow,
+            'receive_block' => $this->receiveBlock,
+            'reject_text' => $this->rejectText,
+            'active' => $this->active,
+            'mailboxes' => $this->mailboxes,
+            'groups' => $this->groups,
+            'created' => $this->created,
+            'modified' => $this->modified,
+        ];
+    }
+
+    /** @return string[] entries of a JSON list column */
+    private static function list(mixed $json): array
+    {
+        $list = is_string($json) ? json_decode($json, true) : null;
+        return is_array($list) ? array_values(array_filter($list, 'is_string')) : [];
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Repository/LookupRepository.php

@@ -0,0 +1,141 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Repository;
+
+use Mailcow\Core\Repository;
+use Mailcow\MailPolicy\Model\Policy;
+
+/**
+ * Read-only lookups of the policy check: mailboxes, aliases, alias domains, groups and the active policies of a
+ * mailbox or group. Addresses are passed in lower case.
+ */
+class LookupRepository extends Repository
+{
+    /** @return array{username: string, domain: string}|null a regular mailbox that is not disabled */
+    public function mailbox(string $username): ?array
+    {
+        $row = $this->query("SELECT `username`, `domain` FROM `mailbox` WHERE `username` = :username AND `kind` = '' AND `active` != '0'",
+            ['username' => $username])->fetch();
+        return is_array($row) ? ['username' => strtolower((string)$row['username']), 'domain' => strtolower((string)$row['domain'])] : null;
+    }
+
+    /** Target domain of an active alias domain */
+    public function aliasDomainTarget(string $domain): ?string
+    {
+        $target = $this->query("SELECT `target_domain` FROM `alias_domain` WHERE `alias_domain` = :domain AND `active` = '1'",
+            ['domain' => $domain])->fetchColumn();
+        return is_string($target) ? strtolower($target) : null;
+    }
+
+    /** A domain or alias domain Postfix delivers itself (as mysql_virtual_domains_maps.cf: active, no backup MX) */
+    public function isLocalDomain(string $domain): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `alias_domain` WHERE `alias_domain` = :d1 AND `active` = '1'
+          UNION SELECT 1 FROM `domain` WHERE `domain` = :d2 AND `active` = '1' AND `backupmx` = '0'",
+            ['d1' => $domain, 'd2' => $domain])->fetchColumn();
+    }
+
+    /**
+     * Stored spelling of a mailbox, alias or temporary alias address. MySQL compares without case and accents, so
+     * Postfix delivers mail for chéf@ to chef@.
+     */
+    public function storedAddress(string $address): ?string
+    {
+        $stored = $this->query("SELECT `username` FROM `mailbox` WHERE `username` = :a1 UNION SELECT `address` FROM `alias` WHERE `address` = :a2
+          UNION SELECT `address` FROM `spamalias` WHERE `address` = :a3 LIMIT 1", ['a1' => $address, 'a2' => $address, 'a3' => $address])->fetchColumn();
+        return is_string($stored) ? strtolower($stored) : null;
+    }
+
+    /** Stored spelling of a domain or alias domain, see storedAddress() */
+    public function storedDomain(string $domain): ?string
+    {
+        $stored = $this->query("SELECT `domain` FROM `domain` WHERE `domain` = :d1 UNION SELECT `alias_domain` FROM `alias_domain` WHERE `alias_domain` = :d2 LIMIT 1",
+            ['d1' => $domain, 'd2' => $domain])->fetchColumn();
+        return is_string($stored) ? strtolower($stored) : null;
+    }
+
+    /** Active group with this distribution address */
+    public function groupByAddress(string $address): ?int
+    {
+        $id = $this->query("SELECT `id` FROM `mailbox_group` WHERE `address` = :address AND `active` = '1'", ['address' => $address])->fetchColumn();
+        return ($id === false) ? null : (int)$id;
+    }
+
+    public function groupAddress(int $id): ?string
+    {
+        $address = $this->query("SELECT `address` FROM `mailbox_group` WHERE `id` = :id AND `active` = '1'", ['id' => $id])->fetchColumn();
+        return is_string($address) && $address !== '' ? strtolower($address) : null;
+    }
+
+    /** Member of an active group */
+    public function isGroupMember(int $groupId, string $username): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `mailbox_group_member` `gm` JOIN `mailbox_group` `g` ON `g`.`id` = `gm`.`group_id`
+          WHERE `gm`.`group_id` = :id AND `gm`.`username` = :username AND `g`.`active` = '1'",
+            ['id' => $groupId, 'username' => $username])->fetchColumn();
+    }
+
+    /**
+     * What Postfix' virtual alias maps find for this key, in their order: an alias (also the own alias of a mailbox
+     * and the alias of a group address) or a temporary alias.
+     *
+     * @return array{kind: string, domain?: string, internal?: bool, owner?: string}|null
+     */
+    public function aliasTarget(string $address): ?array
+    {
+        $alias = $this->query("SELECT `domain`, `internal` FROM `alias` WHERE `address` = :address AND `active` IN ('1', '2')",
+            ['address' => $address])->fetch();
+        if (is_array($alias)) {
+            return ['kind' => 'alias', 'domain' => strtolower((string)$alias['domain']), 'internal' => $alias['internal'] == '1'];
+        }
+        $owner = $this->query("SELECT `goto` FROM `spamalias` WHERE `address` = :address AND (`validity` >= UNIX_TIMESTAMP() OR `permanent` != 0)",
+            ['address' => $address])->fetchColumn();
+        return is_string($owner) ? ['kind' => 'temporary', 'owner' => strtolower($owner)] : null;
+    }
+
+    /** An active catch-all alias of the domain has the internal flag (applies to the whole domain) */
+    public function internalCatchAll(string $domain): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `alias` WHERE `address` = :address AND `internal` = '1' AND `active` IN ('1', '2')",
+            ['address' => '@' . $domain])->fetchColumn();
+    }
+
+    /** An active policy with members restricts sending */
+    public function hasSendRules(): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `mail_policy` `p` JOIN `mail_policy_member` `pm` ON `pm`.`policy_id` = `p`.`id`
+          WHERE `p`.`active` = '1' AND (`p`.`send_mode` != 'all' OR `p`.`send_block` != '[]') LIMIT 1")->fetchColumn();
+    }
+
+    /**
+     * @return Policy[] active policies of the mailbox: assigned to it or to an active group it is a member of; only
+     *                  policies of its own domain, so a group with members of other domains cannot restrict them
+     */
+    public function policiesForMailbox(string $username): array
+    {
+        return $this->policies("SELECT DISTINCT `p`.* FROM `mail_policy` `p`
+          JOIN `mail_policy_member` `pm` ON `pm`.`policy_id` = `p`.`id`
+          JOIN `mailbox` `m` ON `m`.`username` = :u1 AND `m`.`domain` = `p`.`domain`
+          WHERE `p`.`active` = '1' AND (`pm`.`username` = :u2 OR `pm`.`group_id` IN (
+            SELECT `gm`.`group_id` FROM `mailbox_group_member` `gm` JOIN `mailbox_group` `g` ON `g`.`id` = `gm`.`group_id`
+            WHERE `gm`.`username` = :u3 AND `g`.`active` = '1'))
+          ORDER BY `p`.`id`", ['u1' => $username, 'u2' => $username, 'u3' => $username]);
+    }
+
+    /** @return Policy[] active policies assigned to the group */
+    public function policiesForGroup(int $groupId): array
+    {
+        return $this->policies("SELECT DISTINCT `p`.* FROM `mail_policy` `p`
+          JOIN `mail_policy_member` `pm` ON `pm`.`policy_id` = `p`.`id`
+          WHERE `p`.`active` = '1' AND `pm`.`group_id` = :id
+          ORDER BY `p`.`id`", ['id' => $groupId]);
+    }
+
+    /** @return Policy[] */
+    private function policies(string $sql, array $params): array
+    {
+        return array_map(fn(array $row): Policy => Policy::fromRow($row), $this->query($sql, $params)->fetchAll());
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Repository/PolicyRepository.php

@@ -0,0 +1,148 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Repository;
+
+use Mailcow\Core\Context;
+use Mailcow\Core\Repository;
+use Mailcow\MailPolicy\Model\Policy;
+use PDO;
+
+/**
+ * Tables `mail_policy` and `mail_policy_member` (the mailboxes and groups a policy is assigned to), plus the
+ * lookups the editing needs. Assignments go with their mailbox, group or domain (foreign keys, ON DELETE CASCADE).
+ */
+class PolicyRepository extends Repository
+{
+    public function find(int $id): ?Policy
+    {
+        $row = $this->query("SELECT * FROM `mail_policy` WHERE `id` = :id", ['id' => $id])->fetch();
+        return is_array($row) ? $this->withMembers(Policy::fromRow($row)) : null;
+    }
+
+    /**
+     * @param string[] $domains limit to these domains, [] = all visible
+     * @return int[] ids of the policies visible to the caller, ordered by domain and name
+     */
+    public function visibleIds(Context $context, array $domains = []): array
+    {
+        if ($context->hasAdminRights()) {
+            [$visible, $params] = ['1=1', []];
+        } elseif ($context->isDomainAdmin()) {
+            [$visible, $params] = ["`domain` IN (SELECT `domain` FROM `domain_admins` WHERE `active` = '1' AND `username` = :vis_da)",
+                ['vis_da' => $context->username]];
+        } else {
+            return [];
+        }
+        $sql = "SELECT `id` FROM `mail_policy` WHERE $visible";
+        if (!empty($domains)) {
+            $names = [];
+            foreach (array_values($domains) as $i => $domain) {
+                $names[] = ':dom' . $i;
+                $params['dom' . $i] = $domain;
+            }
+            $sql .= " AND `domain` IN (" . implode(', ', $names) . ")";
+        }
+        return array_map('intval', $this->query($sql . " ORDER BY `domain`, `name`", $params)->fetchAll(PDO::FETCH_COLUMN));
+    }
+
+    public function nameExists(string $domain, string $name, ?int $exceptId = null): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `mail_policy` WHERE `domain` = :domain AND `name` = :name AND `id` != :id",
+            ['domain' => $domain, 'name' => $name, 'id' => $exceptId ?? 0])->fetchColumn();
+    }
+
+    /** Inserts or updates the policy with its assignments; returns its id */
+    public function save(Policy $policy): int
+    {
+        return $this->transaction(function () use ($policy): int {
+            if ($policy->id === null) {
+                $policy->id = $this->insertRow('mail_policy', $policy->toRow());
+            } else {
+                $this->updateRow('mail_policy', $policy->id, $policy->toRow());
+                $this->query("DELETE FROM `mail_policy_member` WHERE `policy_id` = :id", ['id' => $policy->id]);
+            }
+            foreach ($policy->mailboxes as $username) {
+                $this->insertRow('mail_policy_member', ['policy_id' => $policy->id, 'username' => $username]);
+            }
+            foreach ($policy->groups as $groupId) {
+                $this->insertRow('mail_policy_member', ['policy_id' => $policy->id, 'group_id' => $groupId]);
+            }
+            return $policy->id;
+        });
+    }
+
+    public function delete(int $id): void
+    {
+        $this->query("DELETE FROM `mail_policy` WHERE `id` = :id", ['id' => $id]);
+    }
+
+    /** Address entries of all lists follow a renamed mailbox or alias */
+    public function renameAddress(string $old, string $new): void
+    {
+        $this->transaction(function () use ($old, $new): void {
+            $columns = ['send_allow', 'send_block', 'receive_allow', 'receive_block'];
+            foreach ($this->query("SELECT `id`, `" . implode('`, `', $columns) . "` FROM `mail_policy`")->fetchAll() as $row) {
+                $changed = [];
+                foreach ($columns as $column) {
+                    $entries = json_decode((string)$row[$column], true);
+                    if (is_array($entries) && in_array($old, $entries, true)) {
+                        $changed[$column] = json_encode(array_values(array_unique(array_map(fn(string $entry): string => ($entry === $old) ? $new : $entry, $entries))));
+                    }
+                }
+                if ($changed !== []) {
+                    $this->updateRow('mail_policy', (int)$row['id'], $changed);
+                }
+            }
+        });
+    }
+
+    /** A primary domain (policies never belong to alias domains) */
+    public function isDomain(string $domain): bool
+    {
+        return (bool)$this->query("SELECT 1 FROM `domain` WHERE `domain` = :domain", ['domain' => $domain])->fetchColumn();
+    }
+
+    /** Domain of a regular mailbox, null if there is none */
+    public function mailboxDomain(string $username): ?string
+    {
+        $domain = $this->query("SELECT `domain` FROM `mailbox` WHERE `username` = :username AND `kind` = ''", ['username' => $username])->fetchColumn();
+        return is_string($domain) ? $domain : null;
+    }
+
+    public function groupDomain(int $id): ?string
+    {
+        $domain = $this->query("SELECT `domain` FROM `mailbox_group` WHERE `id` = :id", ['id' => $id])->fetchColumn();
+        return is_string($domain) ? $domain : null;
+    }
+
+    /** @return array[] id, name, domain, address of the groups in these domains (choices of the forms) */
+    public function groupsIn(array $domains): array
+    {
+        if (empty($domains)) {
+            return [];
+        }
+        $names = [];
+        $params = [];
+        foreach (array_values($domains) as $i => $domain) {
+            $names[] = ':dom' . $i;
+            $params['dom' . $i] = $domain;
+        }
+        return $this->query("SELECT `id`, `name`, `domain`, `address` FROM `mailbox_group` WHERE `domain` IN (" . implode(', ', $names) . ")
+          ORDER BY `domain`, `name`", $params)->fetchAll();
+    }
+
+    private function withMembers(Policy $policy): Policy
+    {
+        foreach ($this->query("SELECT `username`, `group_id` FROM `mail_policy_member` WHERE `policy_id` = :id ORDER BY `username`, `group_id`",
+            ['id' => $policy->id])->fetchAll() as $row) {
+            if ($row['username'] !== null) {
+                $policy->mailboxes[] = (string)$row['username'];
+            } elseif ($row['group_id'] !== null) {
+                $policy->groups[] = (int)$row['group_id'];
+            }
+        }
+        return $policy;
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Service/PolicyEngine.php

@@ -0,0 +1,325 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Service;
+
+use Mailcow\MailPolicy\Model\Decision;
+use Mailcow\MailPolicy\Model\Policy;
+use Mailcow\MailPolicy\Repository\LookupRepository;
+
+/**
+ * Policy check of one recipient, asked by Postfix at RCPT TO (data/conf/rspamd/dynmaps/mailpolicy.php).
+ *
+ * Send part: the policies of the logged-in mailbox (assigned to it or to its groups) and of the mailbox the
+ * sender address belongs to. Receive part: what Postfix delivers the recipient to, looked up in the order of its
+ * virtual alias maps (address, address without +tag, mailbox of an alias domain): the policies of the mailbox, of
+ * the group address or of the owner of a temporary alias, and the `internal` flag of the alias (a catch-all alias
+ * with the flag covers its whole domain). Mail sent to an alias or group reaches its members without their own
+ * policies. Every policy must allow the mail.
+ *
+ * Internal: a recipient in the domain of the policy or one of its alias domains; a sender logged in with a
+ * mailbox of that domain. Entries of a local domain or address count for logged-in senders only, so they cannot
+ * be forged; block entries also match the envelope sender. External entries are compared with the envelope sender.
+ * Addresses are compared the way Postfix finds them: lower case, without trailing dot, in their stored spelling
+ * (MySQL ignores accents). Recipients routed through localhost (user%domain@localhost, domain!user@localhost,
+ * user@domain@localhost) are refused, Postfix would deliver them to the routed address.
+ *
+ * Dovecot submits Sieve redirects, vacation replies and notifications on port 588 without login, SOGo sends
+ * reminders with a service login: mail with the address of a mailbox counts as sent by that mailbox. Other mail of
+ * these services (bounces redirected with the null sender, Sieve rejects) has no known sender: it is checked like
+ * mail from outside and does not leave the mailcow while any policy restricts sending. Quota warnings pass.
+ */
+class PolicyEngine
+{
+    /** Ports of mailcow's own deliveries: quarantine release (590), BCC and archive copies (591) */
+    private const INTERNAL_PORTS = [590, 591];
+    /** Submission of SOGo and Dovecot, without login reachable from mailcow's own network only */
+    private const SERVICE_PORT = 588;
+    /** Domain of the Dovecot master login of mailcow's services (SOGo reminders) */
+    private const SERVICE_LOGIN_DOMAIN = 'mailcow.local';
+    /** HELO of the quota warning copies of Dovecot (quota_notify.py), configured by admins */
+    private const QUOTA_HELO = 'quotanotification';
+    /** Recipient without domain every server accepts (RFC 5321) */
+    private const POSTMASTER = 'postmaster';
+    /** Postfix delivers these destinations itself (mydestination), user%domain and domain!user route from there */
+    private const LOCAL_DESTINATIONS = ['localhost', 'localhost.localdomain'];
+
+    /** Lookups of the current check */
+    private array $cache = [];
+
+    public function __construct(private LookupRepository $lookup)
+    {
+    }
+
+    /** $login: SASL username, '' if not logged in; $port: smtpd port of the request, 0 if unknown; $helo: HELO name */
+    public function check(string $sender, string $recipient, string $login, int $port = 0, string $helo = ''): Decision
+    {
+        $this->cache = [];
+        $recipient = self::address($recipient);
+        if (in_array($port, self::INTERNAL_PORTS, true) || $recipient === '' || $recipient === self::POSTMASTER) {
+            return Decision::allow();
+        }
+        if (self::isRouted($recipient)) {
+            return Decision::routedAddress();
+        }
+        $recipient = $this->stored($recipient);
+        $sender = $this->stored(self::address($sender));
+        $login = self::address($login);
+        $serviceLogin = self::domainOf($login) === self::SERVICE_LOGIN_DOMAIN;
+        $account = null;
+        if ($login !== '' && !$serviceLogin) {
+            $account = $this->cached('mailbox', $login);
+        } elseif ($serviceLogin || $port === self::SERVICE_PORT) {
+            if ($port === self::SERVICE_PORT && !$serviceLogin && strtolower($helo) === self::QUOTA_HELO) {
+                return Decision::allow();
+            }
+            // without a mailbox sender the sending mailbox is unknown
+            $account = $this->senderMailbox($sender);
+            if ($account === null && !$this->cached('isLocalDomain', self::domainOf($recipient)) && $this->lookup->hasSendRules()) {
+                return Decision::deny('send');
+            }
+        }
+        foreach ($this->sendingPolicies($account, $sender) as $policy) {
+            if (!$this->allows($policy->sendMode, $policy->sendAllow, $policy->sendBlock, $this->isInternalRecipient($recipient, $policy->domain),
+                fn(string $entry): bool => $this->recipientMatches($entry, $recipient))) {
+                return Decision::deny('send', $policy);
+            }
+        }
+        foreach ($this->receivingPolicies($recipient) as $policy) {
+            if (!$this->allows($policy->receiveMode, $policy->receiveAllow, $policy->receiveBlock,
+                $account !== null && $account['domain'] === $policy->domain,
+                fn(string $entry, bool $block): bool => $this->senderMatches($entry, $sender, $account, $block))) {
+                return Decision::deny('receive', $policy);
+            }
+        }
+        return Decision::allow();
+    }
+
+    /** Blocked entries first; then the mode decides. $matches($entry, $block) */
+    private function allows(string $mode, array $allow, array $block, bool $internal, callable $matches): bool
+    {
+        foreach ($block as $entry) {
+            if ($matches($entry, true)) {
+                return false;
+            }
+        }
+        return match ($mode) {
+            'internal' => $internal || $this->any($allow, $matches),
+            'list' => $this->any($allow, $matches),
+            default => true,
+        };
+    }
+
+    private function any(array $entries, callable $matches): bool
+    {
+        foreach ($entries as $entry) {
+            if ($matches($entry, false)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /** @return array{username: string, domain: string}|null mailbox of the sender address */
+    private function senderMailbox(string $sender): ?array
+    {
+        return str_contains($sender, '@') ? $this->cached('mailbox', $this->resolve(self::untagged($sender))) : null;
+    }
+
+    /** @return Policy[] of the logged-in mailbox and of the mailbox it sends as */
+    private function sendingPolicies(?array $account, string $sender): array
+    {
+        if ($account === null) {
+            return [];
+        }
+        $policies = $this->lookup->policiesForMailbox($account['username']);
+        $sentAs = $this->senderMailbox($sender);
+        if ($sentAs !== null && $sentAs['username'] !== $account['username']) {
+            $policies = array_merge($policies, $this->lookup->policiesForMailbox($sentAs['username']));
+        }
+        return self::unique($policies);
+    }
+
+    /** @return Policy[] of what Postfix delivers the recipient to, see the class comment */
+    private function receivingPolicies(string $recipient): array
+    {
+        // the address, then without +tag; an alias domain maps to the mailbox in its target domain and Postfix
+        // looks up the result again with the +tag
+        [$address, $target] = $this->aliasTarget([$recipient, self::untagged($recipient)]);
+        $resolved = $this->resolve($recipient);
+        if ($target === null && $resolved !== $recipient) {
+            [$address, $target] = $this->aliasTarget([$resolved, self::untagged($resolved)]);
+        }
+        $address ??= self::untagged($resolved);
+        if (($target['kind'] ?? '') === 'temporary') {
+            $address = $target['owner'];
+        }
+        $policies = ($this->cached('mailbox', $address) !== null) ? $this->lookup->policiesForMailbox($address) : [];
+        $group = $this->lookup->groupByAddress($address);
+        if ($group !== null) {
+            $policies = array_merge($policies, $this->lookup->policiesForGroup($group));
+        }
+        // the `internal` flag of an alias or group: only senders of its domain
+        if (!empty($target['internal'])) {
+            $policies[] = $this->internalRule($target['domain']);
+        }
+        foreach (array_unique([self::domainOf($recipient), $this->resolveDomain(self::domainOf($recipient))]) as $domain) {
+            if ($this->lookup->internalCatchAll($domain)) {
+                $policies[] = $this->internalRule($domain);
+            }
+        }
+        return self::unique($policies);
+    }
+
+    /** @return array{0: ?string, 1: ?array} the first key Postfix' virtual alias maps find, with what they find */
+    private function aliasTarget(array $keys): array
+    {
+        foreach (array_unique($keys) as $key) {
+            $target = $this->lookup->aliasTarget($key);
+            if ($target !== null) {
+                return [$key, $target];
+            }
+        }
+        return [null, null];
+    }
+
+    /** Receive rule of the `internal` flag */
+    private function internalRule(string $domain): Policy
+    {
+        $policy = new Policy();
+        $policy->domain = $this->resolveDomain($domain);
+        $policy->receiveMode = 'internal';
+        return $policy;
+    }
+
+    private function isInternalRecipient(string $recipient, string $domain): bool
+    {
+        return $this->resolveDomain(self::domainOf($recipient)) === $domain;
+    }
+
+    private function recipientMatches(string $entry, string $recipient): bool
+    {
+        $address = $this->resolve(self::untagged($recipient));
+        if (str_starts_with($entry, 'group:')) {
+            $id = (int)substr($entry, 6);
+            return $this->cached('groupAddress', $id) === $address
+                || ($this->cached('mailbox', $address) !== null && $this->cached('isGroupMember', $id, $address));
+        }
+        if (str_contains($entry, '@')) {
+            return $this->resolve($entry) === $address;
+        }
+        return $this->resolveDomain(self::domainOf($address)) === $this->resolveDomain($entry);
+    }
+
+    /** $block: a block entry, which also matches the envelope sender (refusing a forged sender is no risk) */
+    private function senderMatches(string $entry, string $sender, ?array $account, bool $block): bool
+    {
+        $address = $this->resolve(self::untagged($sender));
+        // the sender address of a local entry only counts when logged in: Postfix checked that the login may use it
+        $useAddress = $account !== null || $block;
+        if (str_starts_with($entry, 'group:')) {
+            $id = (int)substr($entry, 6);
+            return ($account !== null && $this->cached('isGroupMember', $id, $account['username']))
+                || ($useAddress && ($this->cached('groupAddress', $id) === $address
+                    || ($this->cached('mailbox', $address) !== null && $this->cached('isGroupMember', $id, $address))));
+        }
+        if (str_contains($entry, '@')) {
+            return $this->cached('isLocalDomain', self::domainOf($entry))
+                ? ($account !== null && $account['username'] === $this->resolve($entry)) || ($useAddress && $address === $this->resolve($entry))
+                : self::untagged($sender) === $entry;
+        }
+        return $this->cached('isLocalDomain', $entry)
+            ? ($account !== null && $account['domain'] === $this->resolveDomain($entry))
+                || ($useAddress && $this->resolveDomain(self::domainOf($address)) === $this->resolveDomain($entry))
+            : self::domainOf($sender) === $entry;
+    }
+
+    /**
+     * Stored spelling of an address of this mailcow: Postfix finds chéf@ as chef@ (MySQL ignores accents). Only
+     * addresses with non-ASCII characters can differ, as they are already in lower case.
+     */
+    private function stored(string $address): string
+    {
+        if (!preg_match('/[\x80-\xff]/', $address) || !str_contains($address, '@')) {
+            return $address;
+        }
+        foreach (array_unique([$address, self::untagged($address)]) as $key) {
+            $stored = $this->cached('storedAddress', $key);
+            if ($stored !== null) {
+                return $stored;
+            }
+        }
+        $domain = $this->cached('storedDomain', self::domainOf($address));
+        return ($domain === null) ? $address : substr($address, 0, strrpos($address, '@') + 1) . $domain;
+    }
+
+    /** Address in an alias domain as the address in its target domain */
+    private function resolve(string $address): string
+    {
+        $domain = self::domainOf($address);
+        $target = ($domain !== '') ? $this->cached('aliasDomainTarget', $domain) : null;
+        return ($target === null) ? $address : substr($address, 0, strrpos($address, '@') + 1) . $target;
+    }
+
+    private function resolveDomain(string $domain): string
+    {
+        return ($domain === '') ? '' : ($this->cached('aliasDomainTarget', $domain) ?? $domain);
+    }
+
+    /** A lookup, done once per check: long lists ask the same domains and groups again */
+    private function cached(string $method, int|string ...$args): mixed
+    {
+        $key = $method . "\0" . implode("\0", $args);
+        if (!array_key_exists($key, $this->cache)) {
+            $this->cache[$key] = $this->lookup->$method(...$args);
+        }
+        return $this->cache[$key];
+    }
+
+    /** @param Policy[] $policies @return Policy[] without repeated policies */
+    private static function unique(array $policies): array
+    {
+        $unique = [];
+        foreach ($policies as $policy) {
+            $unique[$policy->id ?? 'internal:' . $policy->domain] = $policy;
+        }
+        return array_values($unique);
+    }
+
+    /** Lower case, without angle brackets, quotes and trailing dot of the domain, as Postfix resolves it; '' = null sender */
+    private static function address(string $value): string
+    {
+        $value = strtolower(trim($value, " \t\r\n<>"));
+        $at = strrpos($value, '@');
+        return ($at === false) ? $value : str_replace('"', '', substr($value, 0, $at)) . '@' . rtrim(substr($value, $at + 1), '.');
+    }
+
+    /**
+     * Postfix would deliver the recipient elsewhere: no domain, or routing through a local destination
+     * (localhost, the IP of the server) with %, ! or a second @ in the local part
+     */
+    private static function isRouted(string $address): bool
+    {
+        $at = strrpos($address, '@');
+        if ($at === false || $at === 0 || $at === strlen($address) - 1) {
+            return true;
+        }
+        $domain = substr($address, $at + 1);
+        return (in_array($domain, self::LOCAL_DESTINATIONS, true) || str_starts_with($domain, '['))
+            && strpbrk(substr($address, 0, $at), '@%!') !== false;
+    }
+
+    private static function untagged(string $address): string
+    {
+        $at = strrpos($address, '@');
+        $pos = ($at === false) ? false : strpos(substr($address, 0, $at), '+');
+        return ($pos === false || $pos === 0) ? $address : substr($address, 0, $pos) . substr($address, $at);
+    }
+
+    private static function domainOf(string $address): string
+    {
+        $at = strrpos($address, '@');
+        return ($at === false) ? '' : substr($address, $at + 1);
+    }
+}

data/web/inc/lib/mailcow/MailPolicy/Service/PolicyService.php

@@ -0,0 +1,351 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\MailPolicy\Service;
+
+use Mailcow\Core\AccessDenied;
+use Mailcow\Core\Context;
+use Mailcow\Core\Input;
+use Mailcow\Core\UserError;
+use Mailcow\MailPolicy\Model\Decision;
+use Mailcow\MailPolicy\Model\Policy;
+use Mailcow\MailPolicy\Repository\PolicyRepository;
+
+/**
+ * Use cases of mail policies.
+ *
+ * Read: admins all policies (also read-only API keys); domain admins with the `mail_policies` ACL the policies
+ *       of their domains.
+ * Edit: admins; domain admins with the ACL for policies of their domains. A policy is assigned to mailboxes and
+ *       groups of its own domain; `group:<id>` entries name groups of that domain. Groups need the `mailbox_groups`
+ *       ACL as well: without it a domain admin sees no groups and keeps the group entries and assignments.
+ */
+class PolicyService
+{
+    private const MAX_ENTRIES = 500;
+    /** The reject text goes into the SMTP reply: printable ASCII */
+    private const MAX_REJECT_TEXT = 200;
+    private const LISTS = ['send_allow' => 'sendAllow', 'send_block' => 'sendBlock', 'receive_allow' => 'receiveAllow', 'receive_block' => 'receiveBlock'];
+
+    public function __construct(private PolicyRepository $repo, private PolicyEngine $engine, private Context $context)
+    {
+    }
+
+    public function canRead(): bool
+    {
+        return $this->context->hasAdminRights()
+            || ($this->context->isDomainAdmin() && $this->context->hasAcl('mail_policies'));
+    }
+
+    /** @throws AccessDenied unless the caller may edit policies at all */
+    public function requireEditor(): void
+    {
+        if (!$this->canRead() || $this->context->isReadOnlyApi()) {
+            throw new AccessDenied();
+        }
+    }
+
+    public function get(int $id): ?Policy
+    {
+        $policy = $this->canRead() ? $this->repo->find($id) : null;
+        return ($policy !== null && $this->visible($policy)) ? $policy : null;
+    }
+
+    /** @return int[] */
+    public function visibleIds(array $domains = []): array
+    {
+        return $this->canRead() ? $this->repo->visibleIds($this->context, $domains) : [];
+    }
+
+    public function canEdit(Policy $policy): bool
+    {
+        return $this->canRead() && !$this->context->isReadOnlyApi() && $this->visible($policy);
+    }
+
+    public function toArray(Policy $policy): array
+    {
+        return $policy->toArray() + ['can_edit' => (int)$this->canEdit($policy)];
+    }
+
+    /** @throws UserError */
+    public function create(array $input): Policy
+    {
+        $this->requireEditor();
+        $policy = new Policy();
+        $policy->domain = $this->domainFor($input['domain'] ?? null);
+        $this->apply($policy, $input);
+        $this->repo->save($policy);
+        return $policy;
+    }
+
+    /** Attributes missing in $input keep their value @throws UserError */
+    public function update(int $id, array $input): Policy
+    {
+        $policy = $this->editable($id);
+        $this->apply($policy, $input);
+        $this->repo->save($policy);
+        return $policy;
+    }
+
+    /** @throws UserError */
+    public function delete(int $id): Policy
+    {
+        $policy = $this->editable($id);
+        $this->repo->delete($id);
+        return $policy;
+    }
+
+    /** Address entries of the lists follow a renamed mailbox or alias; called after the rename, without permission check */
+    public function addressRenamed(string $old, string $new): void
+    {
+        $this->repo->renameAddress(strtolower($old), strtolower($new));
+    }
+
+    /** @return array[] id, name, domain, address of the groups in these domains (choices of the forms) */
+    public function groupChoices(array $domains): array
+    {
+        return ($this->canRead() && $this->canUseGroups()) ? $this->repo->groupsIn($domains) : [];
+    }
+
+    private function canUseGroups(): bool
+    {
+        return $this->context->hasAdminRights() || $this->context->hasAcl('mailbox_groups');
+    }
+
+    /**
+     * "Test a rule": would the mail be accepted? A sender that is a mailbox counts as logged in when $loggedIn.
+     *
+     * @return array{allowed: int, side: string, policy: ?string, internal_alias: int, text: string}
+     * @throws UserError
+     */
+    public function test(mixed $sender, mixed $recipient, bool $loggedIn): array
+    {
+        if (!$this->canRead()) {
+            throw new AccessDenied();
+        }
+        $sender = strtolower((string)Input::text($sender));
+        $recipient = strtolower((string)Input::text($recipient));
+        if (($sender !== '' && !filter_var($sender, FILTER_VALIDATE_EMAIL)) || !filter_var($recipient, FILTER_VALIDATE_EMAIL)) {
+            throw new UserError('mail_policy_test_invalid');
+        }
+        // domain admins test mail of their domains; a sender of another domain counts as not logged in
+        $ownSender = $this->context->hasAdminRights() || $this->context->canAccessDomain(self::domainOf($sender));
+        if (!$ownSender && !$this->context->canAccessDomain(self::domainOf($recipient))) {
+            throw new AccessDenied();
+        }
+        $login = ($loggedIn && $ownSender && $this->repo->mailboxDomain($sender) !== null) ? $sender : '';
+        $decision = $this->engine->check($sender, $recipient, $login);
+        $policy = $decision->policy;
+        $hidden = $policy !== null && $policy->id !== null && !$this->visible($policy);
+        return [
+            'allowed' => (int)$decision->allowed,
+            'side' => $decision->side,
+            'policy' => ($policy !== null && $policy->id !== null && !$hidden) ? $policy->name : null,
+            'internal_alias' => (int)($policy !== null && $policy->id === null),
+            'logged_in' => (int)($login !== ''),
+            // the text of a policy of another domain stays hidden
+            'text' => $decision->allowed ? '' : ($hidden ? Decision::defaultText($decision->side) : $decision->text()),
+        ];
+    }
+
+    private function visible(Policy $policy): bool
+    {
+        return $this->context->hasAdminRights() || $this->context->canAccessDomain($policy->domain);
+    }
+
+    /** @throws UserError */
+    private function editable(int $id): Policy
+    {
+        $this->requireEditor();
+        $policy = $this->get($id);
+        if ($policy === null || !$this->canEdit($policy)) {
+            throw new AccessDenied();
+        }
+        return $policy;
+    }
+
+    /** @throws UserError */
+    private function domainFor(mixed $value): string
+    {
+        $domain = strtolower((string)Input::text($value));
+        if ($domain === '' || !$this->repo->isDomain($domain)) {
+            throw new UserError('domain_not_found', [htmlspecialchars((string)Input::text($value))]);
+        }
+        if (!$this->context->hasAdminRights() && !$this->context->canAccessDomain($domain)) {
+            throw new AccessDenied();
+        }
+        return $domain;
+    }
+
+    /** @throws UserError */
+    private function apply(Policy $policy, array $input): void
+    {
+        if (array_key_exists('name', $input) || $policy->id === null) {
+            $name = Input::text($input['name'] ?? null);
+            if ($name === null || $name === '' || mb_strlen($name) > 100 || preg_match('/[\x00-\x1f\x7f]/', $name)) {
+                throw new UserError('mail_policy_name_invalid');
+            }
+            if ($this->repo->nameExists($policy->domain, $name, $policy->id)) {
+                throw new UserError('object_exists', [htmlspecialchars($name)]);
+            }
+            $policy->name = $name;
+        }
+        if (array_key_exists('description', $input)) {
+            $description = Input::text($input['description']);
+            if ($description === null || mb_strlen($description) > 255 || preg_match('/[\x00-\x1f\x7f]/', $description)) {
+                throw new UserError('mail_policy_description_invalid');
+            }
+            $policy->description = $description;
+        }
+        foreach (['send_mode' => 'sendMode', 'receive_mode' => 'receiveMode'] as $key => $property) {
+            if (array_key_exists($key, $input)) {
+                $mode = Input::text($input[$key]);
+                $policy->$property = in_array($mode, Policy::MODES, true) ? $mode : throw new UserError('mail_policy_mode_invalid');
+            }
+        }
+        $groupAccess = $this->canUseGroups();
+        foreach (self::LISTS as $key => $property) {
+            // the UI sends the groups of a list separately (<list>_groups); the API may name them as group:<id>
+            if (!array_key_exists($key, $input) && !array_key_exists($key . '_groups', $input)) {
+                continue;
+            }
+            $entries = array_key_exists($key, $input) ? self::values($input[$key]) : self::withoutGroups($policy->$property);
+            $kept = [];
+            if (!$groupAccess) {
+                // without access to groups the group entries stay (also when sent back unchanged); the form shows no group choices
+                $kept = array_values(array_diff($policy->$property, self::withoutGroups($policy->$property)));
+                $entries = array_values(array_diff(array_map('strtolower', $entries), $kept));
+            } elseif (array_key_exists($key . '_groups', $input)) {
+                $entries = array_merge(self::withoutGroups($entries), array_map(fn(string $id): string => 'group:' . $id, self::values($input[$key . '_groups'])));
+            }
+            $entries = array_values(array_unique(array_merge($this->entries($entries, $policy->domain, $groupAccess), $kept)));
+            if (count($entries) > self::MAX_ENTRIES) {
+                throw new UserError('mail_policy_entries_exceeded', [self::MAX_ENTRIES]);
+            }
+            $policy->$property = $entries;
+        }
+        if (array_key_exists('reject_text', $input)) {
+            $text = Input::text($input['reject_text']);
+            if ($text === null || strlen($text) > self::MAX_REJECT_TEXT || preg_match('/[^\x20-\x7e]/', $text)) {
+                throw new UserError('mail_policy_reject_text_invalid');
+            }
+            $policy->rejectText = $text;
+        }
+        if (array_key_exists('active', $input)) {
+            $policy->active = (int)self::flag($input['active']);
+        }
+        if (array_key_exists('mailboxes', $input)) {
+            $policy->mailboxes = [];
+            foreach (self::limited($input['mailboxes']) as $username) {
+                $username = strtolower($username);
+                if ($this->repo->mailboxDomain($username) !== $policy->domain) {
+                    throw new UserError('mail_policy_member_invalid', [htmlspecialchars($username)]);
+                }
+                $policy->mailboxes[$username] = $username;
+            }
+            $policy->mailboxes = array_values($policy->mailboxes);
+        }
+        // without access to groups the assignments stay; only sending them back unchanged is accepted
+        if (array_key_exists('groups', $input) && !$groupAccess && self::values($input['groups']) !== []) {
+            $sent = array_map('intval', self::values($input['groups']));
+            $stored = $policy->groups;
+            sort($sent);
+            sort($stored);
+            if (array_values(array_unique($sent)) !== $stored) {
+                throw new AccessDenied();
+            }
+        }
+        if (array_key_exists('groups', $input) && $groupAccess) {
+            $policy->groups = [];
+            foreach (self::limited($input['groups']) as $value) {
+                $id = Input::intInRange($value, 1, PHP_INT_MAX);
+                if ($id === null || $this->repo->groupDomain($id) !== $policy->domain) {
+                    throw new UserError('mail_policy_member_invalid', [htmlspecialchars($value)]);
+                }
+                $policy->groups[$id] = $id;
+            }
+            $policy->groups = array_values($policy->groups);
+        }
+    }
+
+    /**
+     * Entries of a list: addresses, domains (a leading @ is dropped) and group:<id> of a group of the policy's
+     * domain, lower case, without repeats.
+     *
+     * @param string[] $values
+     * @return string[]
+     * @throws UserError
+     */
+    private function entries(array $values, string $domain, bool $groupAccess): array
+    {
+        $entries = [];
+        foreach (self::limited(array_map('strtolower', $values)) as $entry) {
+            if (str_starts_with($entry, 'group:')) {
+                $id = Input::intInRange(substr($entry, 6), 1, PHP_INT_MAX);
+                if (!$groupAccess || $id === null || $this->repo->groupDomain($id) !== $domain) {
+                    throw new UserError('mail_policy_entry_invalid', [htmlspecialchars($entry)]);
+                }
+                $entry = 'group:' . $id;
+            } elseif (str_contains(ltrim($entry, '@'), '@')) {
+                if (!filter_var($entry, FILTER_VALIDATE_EMAIL)) {
+                    throw new UserError('mail_policy_entry_invalid', [htmlspecialchars($entry)]);
+                }
+            } else {
+                $entry = ltrim($entry, '@');
+                if (!str_contains($entry, '.') || !filter_var($entry, FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME)) {
+                    throw new UserError('mail_policy_entry_invalid', [htmlspecialchars($entry)]);
+                }
+            }
+            $entries[$entry] = $entry;
+        }
+        return array_values($entries);
+    }
+
+    /**
+     * Values of a list field without repeats, at most MAX_ENTRIES (checked before anything is looked up)
+     *
+     * @return string[]
+     * @throws UserError
+     */
+    private static function limited(mixed $value): array
+    {
+        $values = array_values(array_unique(self::values($value)));
+        if (count($values) > self::MAX_ENTRIES) {
+            throw new UserError('mail_policy_entries_exceeded', [self::MAX_ENTRIES]);
+        }
+        return $values;
+    }
+
+    /** @return string[] entries without group:<id> */
+    private static function withoutGroups(array $entries): array
+    {
+        return array_values(array_filter($entries, fn(string $entry): bool => !str_starts_with(strtolower($entry), 'group:')));
+    }
+
+    /**
+     * Values of a list field: an array (multi-select, JSON) or a string separated by line breaks, commas or spaces.
+     *
+     * @return string[]
+     */
+    private static function values(mixed $value): array
+    {
+        $values = is_array($value) ? $value : preg_split('/[\s,;]+/', (string)Input::text($value));
+        return array_values(array_filter(array_map(fn(mixed $v): string => is_scalar($v) ? trim((string)$v) : '', $values), 'strlen'));
+    }
+
+    /** Checkbox or API flag; a hidden "0" + checkbox pair arrives as ["0", "1"] when checked */
+    private static function flag(mixed $value): bool
+    {
+        if (is_array($value)) {
+            $value = end($value);
+        }
+        return filter_var($value, FILTER_VALIDATE_BOOLEAN);
+    }
+
+    private static function domainOf(string $address): string
+    {
+        $at = strrpos($address, '@');
+        return ($at === false) ? '' : substr($address, $at + 1);
+    }
+}

data/web/js/site/mail-policy.js

@@ -0,0 +1,159 @@
+// Mail policies (admin/domainadmin mailbox page): list, domain choices of the add modal, test of a rule. Loaded via $js_minifier.
+var mailcowMailPolicy = (function($) {
+  'use strict';
+
+  // lang.mail_policy of the mailbox page, '' if missing
+  function L(key) {
+    var src = (typeof lang !== 'undefined' && lang && lang.mail_policy) ? lang.mail_policy : {};
+    return (src[key] !== undefined && src[key] !== null) ? src[key] : '';
+  }
+  function esc(s) {
+    return escapeHtml(s === null || s === undefined ? '' : s);
+  }
+
+  // mode of one direction with the number of allowed and blocked entries
+  function sideCell(mode, allow, block) {
+    var html = esc(L('summary_' + mode));
+    var counts = [];
+    if (mode !== 'all' && allow.length) counts.push('+' + allow.length + ' ' + esc(L('summary_allowed')));
+    if (block.length) counts.push(block.length + ' ' + esc(L('summary_blocked')));
+    return html + (counts.length ? '<div class="small text-muted">' + counts.join(', ') + '</div>' : '');
+  }
+
+  function assignedCell(item) {
+    var list = (item.mailboxes || []).slice(0, 3).map(esc);
+    if ((item.mailboxes || []).length > 3) list.push('<span class="text-muted">+' + (item.mailboxes.length - 3) + '</span>');
+    if ((item.groups || []).length) list.push('<i class="bi bi-people"></i> ' + esc(L('groups')) + ': ' + item.groups.length);
+    return list.length ? list.join('<br>') : '<span class="text-muted">' + esc(L('assigned_none')) + '</span>';
+  }
+
+  function drawTable() {
+    if ($.fn.DataTable.isDataTable('#mail_policy_table')) {
+      $('#mail_policy_table').DataTable().columns.adjust().responsive.recalc();
+      return;
+    }
+    $('#mail_policy_table').DataTable({
+      responsive: true,
+      processing: true,
+      serverSide: false,
+      stateSave: true,
+      pageLength: pagination_size,
+      dom: "<'row'<'col-sm-12 col-md-6'f><'col-sm-12 col-md-6'l>>" + "tr" +
+           "<'row'<'col-sm-12 col-md-5'i><'col-sm-12 col-md-7'p>>",
+      language: lang_datatables,
+      order: [[3, 'asc']],
+      ajax: {
+        type: "GET",
+        url: "/api/v1/get/mail-policy/all",
+        dataSrc: function(json) {
+          if (!Array.isArray(json)) return [];
+          $.each(json, function(i, item) {
+            item.chkbox = item.can_edit ?
+              '<input type="checkbox" class="form-check-input" data-id="mail_policy" name="multi_select" value="' + encodeURIComponent(item.id) + '" />' :
+              '<input type="checkbox" class="form-check-input" disabled />';
+            item.name_display = esc(item.name) + (item.description ? '<div class="small text-muted">' + esc(item.description) + '</div>' : '');
+            item.send_display = sideCell(item.send_mode, item.send_allow || [], item.send_block || []);
+            item.receive_display = sideCell(item.receive_mode, item.receive_allow || [], item.receive_block || []);
+            item.assigned_display = assignedCell(item);
+            item.action = '<div class="btn-group">' +
+              '<a href="/edit/mail-policy/' + encodeURIComponent(item.id) + '" class="btn btn-sm btn-xs-lg btn-xs-half btn-secondary"><i class="bi bi-pencil-fill"></i> ' + esc(item.can_edit ? lang.edit : L('view')) + '</a>' +
+              (item.can_edit ? '<a href="#" data-action="delete_selected" data-id="single-mail_policy" data-api-url="delete/mail-policy" data-item="' + encodeURIComponent(item.id) + '" class="btn btn-sm btn-xs-lg btn-xs-half btn-danger"><i class="bi bi-trash"></i> ' + esc(lang.remove) + '</a>' : '') +
+              '</div>';
+          });
+          return json;
+        },
+        error: function() {
+          mailcow_alert_box(L('list_error'), 'danger');
+        }
+      },
+      columns: [
+        {
+          // placeholder, so checkbox will not block child row toggle
+          title: '',
+          data: null,
+          searchable: false,
+          orderable: false,
+          defaultContent: '',
+          responsivePriority: 1
+        },
+        { title: '', data: 'chkbox', searchable: false, orderable: false, defaultContent: '', responsivePriority: 2 },
+        { title: 'ID', data: 'id', defaultContent: '', responsivePriority: 6 },
+        { title: L('name'), data: 'name_display', defaultContent: '', responsivePriority: 2 },
+        { title: L('domain'), data: 'domain', defaultContent: '', responsivePriority: 5 },
+        { title: L('send'), data: 'send_display', defaultContent: '', responsivePriority: 3 },
+        { title: L('receive'), data: 'receive_display', defaultContent: '', responsivePriority: 3 },
+        { title: L('assign'), data: 'assigned_display', defaultContent: '', responsivePriority: 4 },
+        {
+          title: lang.active,
+          data: 'active',
+          defaultContent: '',
+          responsivePriority: 6,
+          render: function(d) { return d == 1 ? '<i class="bi bi-check-lg"></i>' : '<i class="bi bi-x-lg"></i>'; }
+        },
+        {
+          title: lang.action,
+          data: 'action',
+          orderable: false,
+          className: 'dt-sm-head-hidden dt-data-w100 dtr-col-md dt-text-right',
+          responsivePriority: 3,
+          defaultContent: ''
+        }
+      ]
+    });
+  }
+
+  // add modal: mailboxes and groups of the chosen domain only
+  function filterDomain($form) {
+    var domain = $form.find('select.mail-policy-domain-select').val();
+    $form.find('select.mail-policy-mailboxes, select.mail-policy-groups').each(function() {
+      $(this).find('option').each(function() {
+        var other = $(this).data('domain') !== domain;
+        $(this).prop('hidden', other);
+        if (other) $(this).prop('selected', false);
+      });
+      $(this).selectpicker('refresh');
+    });
+  }
+
+  function test(e) {
+    e.preventDefault();
+    var sender = $.trim($('#mail_policy_test_sender').val());
+    var recipient = $.trim($('#mail_policy_test_recipient').val());
+    if (!recipient) return;
+    // an empty sender (bounces) is sent as "-"
+    var url = '/api/v1/get/mail-policy/test/' + encodeURIComponent(sender || '-') + '/' + encodeURIComponent(recipient) +
+      ($('#mail_policy_test_login').is(':checked') ? '/login' : '');
+    $.get(url, function(r) {
+      var html;
+      if (!r || r.allowed === undefined) {
+        html = '<div class="alert alert-danger py-2">' + esc(L('test_invalid')) + '</div>';
+      } else if (r.allowed == 1) {
+        html = '<div class="alert alert-success py-2">' + esc(L('test_allowed')) + '</div>';
+      } else {
+        var reason = r.internal_alias == 1 ? L('test_denied_internal') : r.side === 'address' ? L('test_denied_address') :
+          (r.policy ? L('test_denied_' + r.side).replace('%s', r.policy) : L('test_denied_other'));
+        html = '<div class="alert alert-danger py-2">' + esc(reason) + '<div class="small mt-1"><code>550 5.7.1 ' + esc(r.text) + '</code></div></div>';
+      }
+      if (r && r.allowed !== undefined && sender && r.logged_in == 0 && $('#mail_policy_test_login').is(':checked')) {
+        html += '<div class="small text-muted">' + esc(L('test_not_a_mailbox')) + '</div>';
+      }
+      $('#mail_policy_test_result').html(html);
+    }, 'json').fail(function() {
+      $('#mail_policy_test_result').html('<div class="alert alert-danger py-2">' + esc(lang_danger.generic_server_error) + '</div>');
+    });
+  }
+
+  $(document).ready(function() {
+    $('select.mail-policy-domain-select').on('change', function() {
+      filterDomain($(this).closest('form'));
+    });
+    $('#addMailPolicyModal').on('show.bs.modal', function() {
+      filterDomain($(this).find('form'));
+    });
+    $('#mail_policy_test').on('submit', test);
+  });
+
+  return {
+    drawTable: drawTable
+  };
+})(jQuery);

data/web/js/site/mailbox.js

@@ -2493,6 +2493,7 @@ jQuery(function($){
   onVisible("[id^=sync_job_table]", () => draw_sync_job_table());
   onVisible("[id^=imapsync_source_table]", () => mailcowImapsync.drawSourceTable(role === 'admin' || acl_data.syncjobs === 1));
   onVisible("[id^=mailbox_group_table]", () => mailcowGroups.drawTable());
+  onVisible("[id^=mail_policy_table]", () => mailcowMailPolicy.drawTable());
   onVisible("[id^=filter_table]", () => draw_filter_table());
   onVisible("[id^=bcc_table]", () => draw_bcc_table());
   onVisible("[id^=recipient_map_table]", () => draw_recipient_map_table());

data/web/json_api.php

@@ -280,6 +280,9 @@ if (isset($_GET['query'])) {
         case "mailbox-group":
           process_add_return(\Mailcow\MailboxGroup\MailboxGroupModule::fromGlobals()->api->addGroup($attr));
         break;
+        case "mail-policy":
+          process_add_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->addPolicy($attr));
+        break;
         case "domain":
           switch ($object) {
             case "template":
@@ -858,6 +861,23 @@ if (isset($_GET['query'])) {
             }
           break;
 
+          case "mail-policy":
+            switch ($object) {
+              case "all":
+                process_get_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->getPolicies($extra));
+              break;
+
+              // test/<sender>/<recipient>[/login]: would the mail be accepted?
+              case "test":
+                process_get_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->test((string)$extra, (string)($query[4] ?? ''), ($query[5] ?? '') === 'login'));
+              break;
+
+              default:
+                process_get_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->getPolicy($object));
+              break;
+            }
+          break;
+
           case "logs":
             switch ($object) {
               case "dovecot":
@@ -1779,6 +1799,9 @@ if (isset($_GET['query'])) {
         case "mailbox-group":
           process_delete_return(\Mailcow\MailboxGroup\MailboxGroupModule::fromGlobals()->api->deleteGroups($items));
         break;
+        case "mail-policy":
+          process_delete_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->deletePolicies($items));
+        break;
         case "app-passwd":
           process_delete_return(app_passwd('delete', array('id' => $items)));
         break;
@@ -1953,6 +1976,9 @@ if (isset($_GET['query'])) {
         case "mailbox-group":
           process_edit_return(\Mailcow\MailboxGroup\MailboxGroupModule::fromGlobals()->api->editGroups($items, $attr));
         break;
+        case "mail-policy":
+          process_edit_return(\Mailcow\MailPolicy\MailPolicyModule::fromGlobals()->api->editPolicies($items, $attr));
+        break;
         case "recipient_map":
           process_edit_return(recipient_map('edit', array_merge(array('id' => $items), $attr)));
         break;

data/web/lang/lang.de-de.json

@@ -11,6 +11,7 @@
         "extend_sender_acl": "Eingabe externer Absenderadressen erlauben",
         "filters": "Filter",
         "login_as": "Einloggen als Mailbox-Benutzer",
+        "mail_policies": "Mail-Richtlinien",
         "mailbox_groups": "Gruppen",
         "mailbox_relayhost": "Relayhost für eine Mailbox setzen",
         "prohibited": "Untersagt durch Richtlinie",
@@ -66,7 +67,7 @@
         "hostname": "Host",
         "inactive": "Inaktiv",
         "internal": "Intern",
-        "internal_info": "Interne Aliasse sind nur von der eigenen Domäne oder Alias-Domänen erreichbar.",
+        "internal_info": "Interne Aliasse nehmen nur E-Mails von angemeldeten Absendern ihrer Domain an (auch über Alias-Domains).",
         "sender_allowed": "Als dieser Alias senden erlauben",
         "kind": "Art",
         "mailbox_quota_def": "Standard-Quota einer Mailbox",
@@ -582,6 +583,14 @@
         "is_spam_alias": "%s lautet bereits eine temporäre Alias-Adresse (Spam-Alias-Adresse)",
         "last_key": "Letzter Key kann nicht gelöscht werden, bitte stattdessen die 2FA deaktivieren.",
         "login_failed": "Anmeldung fehlgeschlagen",
+        "mail_policy_description_invalid": "Ungültige Beschreibung",
+        "mail_policy_entries_exceeded": "Höchstens %s Einträge pro Liste oder Auswahl möglich",
+        "mail_policy_entry_invalid": "Ungültige Adresse, Domain oder Gruppe in der Liste: %s",
+        "mail_policy_member_invalid": "Mailbox oder Gruppe %s gehört nicht zur Domain der Richtlinie",
+        "mail_policy_mode_invalid": "Ungültiger Modus",
+        "mail_policy_name_invalid": "Ungültiger Name (1 bis 100 Zeichen)",
+        "mail_policy_reject_text_invalid": "Ungültiger Ablehnungstext: druckbare ASCII-Zeichen, höchstens 200",
+        "mail_policy_test_invalid": "Ungültiger Absender oder Empfänger",
         "mailbox_defquota_exceeds_mailbox_maxquota": "Standard-Quota überschreitet das Limit der maximal erlaubten Größe einer Mailbox",
         "mailbox_invalid": "Mailboxname ist ungültig",
         "mailbox_quota_exceeded": "Speicherplatz überschreitet das Limit (max. %d MiB)",
@@ -829,7 +838,7 @@
         "iam_unlink": "Verknüpfung lösen",
         "inactive": "Inaktiv",
         "internal": "Intern",
-        "internal_info": "Interne Aliasse sind nur von der eigenen Domäne oder Alias-Domänen erreichbar.",
+        "internal_info": "Interne Aliasse nehmen nur E-Mails von angemeldeten Absendern ihrer Domain an (auch über Alias-Domains).",
         "sender_allowed": "Als dieser Alias senden erlauben",
         "sender_allowed_info": "Wenn deaktiviert, kann dieser Alias nur E-Mails empfangen. Verwenden Sie Sender-ACL, um bestimmten Postfächern die Berechtigung zum Senden zu erteilen.",
         "kind": "Art",
@@ -969,7 +978,7 @@
         "imap_grants": "Postfachzugriff",
         "imap_grants_hint": "Mitglieder öffnen diese Mailboxen in ihrem Mailprogramm (Ordner Shared/<mailbox>). Lesen: lesen und als gelesen markieren. Schreiben: zusätzlich ablegen, verschieben und löschen. Vollzugriff: zusätzlich Ordner löschen. Team-Postfächer ohne eigenen Login als geteiltes Postfach markieren.",
         "info": "Gruppen bündeln Postfächer. Eine Gruppe kann eine eigene Adresse haben: ein Alias, der automatisch an alle Mitglieder zustellt. Mitglieder können als andere Adressen senden, auf freigegebene Postfächer, Kalender und Adressbücher zugreifen und ein Postfach-Template erhalten. Vom Identity Provider synchronisierte Mitglieder sind mit IdP markiert.",
-        "internal": "Nur Mails von Absendern der Domain annehmen",
+        "internal": "Nur E-Mails von angemeldeten Absendern der Domain annehmen",
         "list_error": "Gruppen konnten nicht geladen werden",
         "managed_alias": "Wird von Gruppe %s verwaltet",
         "members": "Mitglieder",
@@ -1036,6 +1045,61 @@
         "username": "Benutzername",
         "email": "E-Mail-Adresse"
     },
+    "mail_policy": {
+        "add": "Mail-Richtlinie hinzufügen",
+        "allow_receive": "Erlaubte Absender",
+        "allow_send": "Erlaubte Empfänger",
+        "assign": "Zugewiesen an",
+        "assign_info": "Die Richtlinie gilt für diese Mailboxen und für die Mitglieder dieser Gruppen aus der Domain der Richtlinie, bei einer Gruppe auch für E-Mails an die Gruppenadresse. E-Mails an einen Alias oder eine andere Gruppe erreichen die Mitglieder ohne deren Richtlinien.",
+        "assigned_none": "Nicht zugewiesen",
+        "block_receive": "Gesperrte Absender",
+        "block_send": "Gesperrte Empfänger",
+        "description": "Beschreibung",
+        "domain": "Domain",
+        "entries_info_receive": "Adressen oder Domains, eine pro Zeile, und Gruppen der Domain. Erlaubte Adressen und Domains dieser mailcow gelten nur für angemeldete Absender, gesperrte auch für die Absenderadresse im Umschlag. Externe Absender werden an der Absenderadresse im Umschlag erkannt.",
+        "entries_info_send": "Adressen oder Domains, eine pro Zeile, und Gruppen der Domain.",
+        "groups": "Gruppen",
+        "info": "Mail-Richtlinien legen fest, an wen Mailboxen und Gruppen senden und von wem sie empfangen dürfen, z. B. nur intern oder nur mit bestimmten Domains. Postfix prüft sie für jeden Empfänger und lehnt nicht erlaubte Empfänger mit einem 550-Fehler ab. Eingehende E-Mails erreichen die übrigen Empfänger trotzdem, SOGo sendet eine E-Mail mit einem abgelehnten Empfänger dagegen gar nicht.",
+        "internal_info": "Intern: Empfänger in der Domain der Richtlinie und ihren Alias-Domains; Absender, die mit einer Mailbox dieser Domain angemeldet sind.",
+        "list_error": "Die Mail-Richtlinien konnten nicht geladen werden",
+        "mail_policies": "Mail-Richtlinien",
+        "mailboxes": "Mailboxen",
+        "mode": "Erlaubt",
+        "mode_receive_all": "Alle Absender",
+        "mode_receive_internal": "Interne Absender und die erlaubten Absender",
+        "mode_receive_list": "Nur die erlaubten Absender",
+        "mode_send_all": "Alle Empfänger",
+        "mode_send_internal": "Interne Empfänger und die erlaubten Empfänger",
+        "mode_send_list": "Nur die erlaubten Empfänger",
+        "name": "Name",
+        "policy": "Mail-Richtlinie",
+        "receive": "Empfangen",
+        "receive_info": "Für E-Mails an eine zugewiesene Mailbox oder an die Adresse einer zugewiesenen Gruppe.",
+        "reject_text": "Ablehnungstext",
+        "reject_text_info": "Text der SMTP-Ablehnung (550 5.7.1 …), nur ASCII. Leer: ein Standardtext.",
+        "send": "Senden",
+        "send_info": "Für E-Mails, die eine zugewiesene Mailbox angemeldet sendet oder die unter ihrer Adresse gesendet werden, auch Weiterleitungen per Filter und Abwesenheitsnotizen.",
+        "summary_all": "Alle",
+        "summary_allowed": "erlaubt",
+        "summary_blocked": "gesperrt",
+        "summary_internal": "Intern",
+        "summary_list": "Nur erlaubte",
+        "test": "Regel testen",
+        "test_allowed": "Angenommen: Keine Richtlinie lehnt diese E-Mail ab.",
+        "test_denied_address": "Abgelehnt: Diese Schreibweise leitet über eine andere Adresse um und ist nicht erlaubt.",
+        "test_denied_internal": "Abgelehnt: Die Adresse nimmt nur E-Mails von angemeldeten Absendern ihrer Domain an (interner Alias oder interne Gruppe).",
+        "test_denied_other": "Abgelehnt durch eine Richtlinie einer anderen Domain.",
+        "test_denied_receive": "Abgelehnt durch den Empfangen-Teil der Richtlinie „%s“.",
+        "test_denied_send": "Abgelehnt durch den Senden-Teil der Richtlinie „%s“.",
+        "test_info": "Prüft, ob Postfix die E-Mail für diesen Empfänger annehmen würde. Für Bounces den Absender leer lassen.",
+        "test_invalid": "Geben Sie einen gültigen Empfänger (und Absender) Ihrer Domains ein.",
+        "test_logged_in": "Absender ist angemeldet",
+        "test_not_a_mailbox": "Der Absender ist keine Mailbox Ihrer Domains und wurde als nicht angemeldet geprüft.",
+        "test_recipient": "Empfänger",
+        "test_run": "Testen",
+        "test_sender": "Absender",
+        "view": "Ansehen"
+    },
     "mailbox": {
         "action": "Aktion",
         "activate": "Aktivieren",
@@ -1134,6 +1198,9 @@
         "no_record": "Kein Eintrag für Objekt %s",
         "no_record_single": "Kein Eintrag",
         "owner": "Besitzer",
+        "policies": "Richtlinien",
+        "policies_mail": "Mail",
+        "policies_tls": "TLS",
         "private_comment": "Privater Kommentar",
         "public_comment": "Öffentlicher Kommentar",
         "q_add_header": "bei Mail in Junk-Ordner",
@@ -1348,6 +1415,9 @@
         "learned_ham": "ID %s wurde erfolgreich als Ham gelernt",
         "license_modified": "Änderungen an Lizenz wurden gespeichert",
         "logged_in_as": "Eingeloggt als %s",
+        "mail_policy_added": "Mail-Richtlinie %s hinzugefügt",
+        "mail_policy_modified": "Mail-Richtlinie %s gespeichert",
+        "mail_policy_removed": "Mail-Richtlinie %s entfernt",
         "mailbox_added": "Mailbox %s wurde angelegt",
         "mailbox_modified": "Änderungen an Mailbox %s wurden gespeichert",
         "mailbox_removed": "Mailbox %s wurde entfernt",

data/web/lang/lang.en-gb.json

@@ -11,6 +11,7 @@
         "extend_sender_acl": "Allow to extend sender ACL by external addresses",
         "filters": "Filters",
         "login_as": "Login as mailbox user",
+        "mail_policies": "Mail policies",
         "mailbox_groups": "Groups",
         "mailbox_relayhost": "Change relayhost for a mailbox",
         "prohibited": "Prohibited by ACL",
@@ -66,7 +67,7 @@
         "hostname": "Host",
         "inactive": "Inactive",
         "internal": "Internal",
-        "internal_info": "Internal aliases are only accessible from the own domain or alias domains.",
+        "internal_info": "Internal aliases only accept mail from logged-in senders of their domain (also through alias domains).",
         "sender_allowed": "Allow to send as this alias",
         "kind": "Kind",
         "mailbox_quota_def": "Default mailbox quota",
@@ -518,6 +519,14 @@
         "group_send_as_invalid": "Send-as address %s is invalid or unknown",
         "iam_sync_mode_invalid": "Invalid sync mode",
         "iam_sync_unavailable": "The identity provider cannot be synced (Keycloak and LDAP only)",
+        "mail_policy_description_invalid": "Invalid description",
+        "mail_policy_entries_exceeded": "At most %s entries per list or selection are possible",
+        "mail_policy_entry_invalid": "Invalid address, domain or group in the list: %s",
+        "mail_policy_member_invalid": "Mailbox or group %s does not belong to the domain of the policy",
+        "mail_policy_mode_invalid": "Invalid mode",
+        "mail_policy_name_invalid": "Invalid name (1 to 100 characters)",
+        "mail_policy_reject_text_invalid": "Invalid rejection text: printable ASCII, at most 200 characters",
+        "mail_policy_test_invalid": "Invalid sender or recipient",
         "tfa_login_locked": "Too many failed two-factor logins, please try again later",
         "tfa_removal_blocked": "Two-factor authentication cannot be removed because it is required for your account.",
         "alias_domain_invalid": "Alias domain %s is invalid",
@@ -829,7 +838,7 @@
         "iam_unlink": "Unlink",
         "inactive": "Inactive",
         "internal": "Internal",
-        "internal_info": "Internal aliases are only accessible from the own domain or alias domains.",
+        "internal_info": "Internal aliases only accept mail from logged-in senders of their domain (also through alias domains).",
         "sender_allowed": "Allow to send as this alias",
         "sender_allowed_info": "If disabled, this alias can only receive mail. Use sender ACL to override and grant specific mailboxes permission to send.",
         "kind": "Kind",
@@ -969,7 +978,7 @@
         "imap_grants": "Mailbox access",
         "imap_grants_hint": "Members open these mailboxes in their mail client (folder Shared/<mailbox>). Read: read and mark as read. Write: also file, move and delete mails. Full access: also delete folders. For team mailboxes without a login of their own, mark the mailbox as shared mailbox.",
         "info": "Groups bundle mailboxes. A group can have its own address: an alias that delivers to all members automatically. Members can send as other addresses, access shared mailboxes, calendars and address books and get a mailbox template. Members synced from the identity provider are marked IdP.",
-        "internal": "Only accept mail from senders of the domain",
+        "internal": "Only accept mail from logged-in senders of the domain",
         "list_error": "Groups could not be loaded",
         "managed_alias": "Managed by group %s",
         "members": "Members",
@@ -1036,6 +1045,61 @@
         "username": "Username",
         "email": "Email address"
     },
+    "mail_policy": {
+        "add": "Add mail policy",
+        "allow_receive": "Allowed senders",
+        "allow_send": "Allowed recipients",
+        "assign": "Assigned to",
+        "assign_info": "The policy applies to these mailboxes and to the members of these groups in the policy's domain; for a group also to mail sent to the group address. Mail sent to an alias or another group reaches the members without their policies.",
+        "assigned_none": "Not assigned",
+        "block_receive": "Blocked senders",
+        "block_send": "Blocked recipients",
+        "description": "Description",
+        "domain": "Domain",
+        "entries_info_receive": "Addresses or domains, one per line, and groups of the domain. Allowed addresses and domains of this mailcow count for logged-in senders only, blocked ones also for the envelope sender address. External senders are recognised by the envelope sender address.",
+        "entries_info_send": "Addresses or domains, one per line, and groups of the domain.",
+        "groups": "Groups",
+        "info": "Mail policies define whom mailboxes and groups may send to and receive from, e.g. only internally or only with certain domains. Postfix checks them for every recipient and refuses recipients that are not allowed with a 550 error. Incoming mail still reaches the other recipients, whereas SOGo does not send a mail with a refused recipient at all.",
+        "internal_info": "Internal: recipients in the domain of the policy and its alias domains; senders logged in with a mailbox of this domain.",
+        "list_error": "The mail policies could not be loaded",
+        "mail_policies": "Mail policies",
+        "mailboxes": "Mailboxes",
+        "mode": "Allowed",
+        "mode_receive_all": "All senders",
+        "mode_receive_internal": "Internal senders and the allowed senders",
+        "mode_receive_list": "Only the allowed senders",
+        "mode_send_all": "All recipients",
+        "mode_send_internal": "Internal recipients and the allowed recipients",
+        "mode_send_list": "Only the allowed recipients",
+        "name": "Name",
+        "policy": "Mail policy",
+        "receive": "Receiving",
+        "receive_info": "For mail to an assigned mailbox or to the address of an assigned group.",
+        "reject_text": "Rejection text",
+        "reject_text_info": "Text of the SMTP rejection (550 5.7.1 ...), ASCII only. Empty: a default text.",
+        "send": "Sending",
+        "send_info": "For mail an assigned mailbox sends while logged in, or that is sent with its address, including redirects by filters and vacation replies.",
+        "summary_all": "All",
+        "summary_allowed": "allowed",
+        "summary_blocked": "blocked",
+        "summary_internal": "Internal",
+        "summary_list": "Allowed only",
+        "test": "Test a rule",
+        "test_allowed": "Accepted: no policy refuses this mail.",
+        "test_denied_address": "Refused: this form of the address routes through another address and is not allowed.",
+        "test_denied_internal": "Refused: the address only accepts mail from logged-in senders of its domain (internal alias or group).",
+        "test_denied_other": "Refused by a policy of another domain.",
+        "test_denied_receive": "Refused by the receiving part of the policy \"%s\".",
+        "test_denied_send": "Refused by the sending part of the policy \"%s\".",
+        "test_info": "Checks whether Postfix would accept the mail for this recipient. Leave the sender empty for bounces.",
+        "test_invalid": "Enter a valid recipient (and sender) of your domains.",
+        "test_logged_in": "Sender is logged in",
+        "test_not_a_mailbox": "The sender is no mailbox of your domains and was tested as not logged in.",
+        "test_recipient": "Recipient",
+        "test_run": "Test",
+        "test_sender": "Sender",
+        "view": "View"
+    },
     "mailbox": {
         "action": "Action",
         "activate": "Activate",
@@ -1141,6 +1205,9 @@
         "no_record_single": "No record",
         "open_logs": "Open logs",
         "owner": "Owner",
+        "policies": "Policies",
+        "policies_mail": "Mail",
+        "policies_tls": "TLS",
         "private_comment": "Private comment",
         "public_comment": "Public comment",
         "q_add_header": "when moved to Junk folder",
@@ -1355,6 +1422,9 @@
         "learned_ham": "Successfully learned ID %s as ham",
         "license_modified": "Changes to license have been saved",
         "logged_in_as": "Logged in as %s",
+        "mail_policy_added": "Mail policy %s added",
+        "mail_policy_modified": "Mail policy %s saved",
+        "mail_policy_removed": "Mail policy %s removed",
         "mailbox_added": "Mailbox %s has been added",
         "mailbox_modified": "Changes to mailbox %s have been saved",
         "mailbox_removed": "Mailbox %s has been removed",

data/web/templates/edit/mail-policy-fields.twig

@@ -0,0 +1,84 @@
+{# Fields of a mail policy (add modal, edit page): policy, id (prefix of the element ids), groups (choices: id, name,
+   domain, address), mailboxes (choices), ro, label_class. Groups of a list are sent apart as <list>_groups; without
+   group choices (none in the domain, no access to groups) the group fields are left out and stay unchanged. #}
+{% set entries = {} %}
+{% set listed = {} %}
+{% for key in ['send_allow', 'send_block', 'receive_allow', 'receive_block'] %}
+  {% set plain = [] %}
+  {% set group_ids = [] %}
+  {% for entry in attribute(policy, key)|default([]) %}
+    {% if entry starts with 'group:' %}
+      {% set group_ids = group_ids|merge([entry|slice(6)]) %}
+    {% else %}
+      {% set plain = plain|merge([entry]) %}
+    {% endif %}
+  {% endfor %}
+  {% set entries = entries|merge({(key): plain|join("\n")}) %}
+  {% set listed = listed|merge({(key): group_ids}) %}
+{% endfor %}
+{% for side in ['send', 'receive'] %}
+<legend class="fs-5 mt-4"><i class="bi {{ side == 'send' ? 'bi-send' : 'bi-inbox' }}"></i> {{ attribute(lang.mail_policy, side) }}</legend><hr>
+<p class="text-muted small">{{ attribute(lang.mail_policy, side ~ '_info') }}</p>
+<div class="row mb-2">
+  <label class="control-label col-sm-2{{ label_class }}" for="{{ id }}_{{ side }}_mode">{{ lang.mail_policy.mode }}</label>
+  <div class="col-sm-10">
+    <select class="form-control" name="{{ side }}_mode" id="{{ id }}_{{ side }}_mode"{% if ro %} disabled{% endif %}>
+      {% for mode in ['all', 'internal', 'list'] %}
+      <option value="{{ mode }}"{% if attribute(policy, side ~ '_mode')|default('all') == mode %} selected{% endif %}>{{ attribute(lang.mail_policy, 'mode_' ~ side ~ '_' ~ mode) }}</option>
+      {% endfor %}
+    </select>
+    <small class="text-muted d-block">{{ lang.mail_policy.internal_info }}</small>
+  </div>
+</div>
+{% for list in ['allow', 'block'] %}
+{% set key = side ~ '_' ~ list %}
+<div class="row mb-2">
+  <label class="control-label col-sm-2{{ label_class }}" for="{{ id }}_{{ key }}">{{ attribute(lang.mail_policy, list ~ '_' ~ side) }}</label>
+  <div class="col-sm-10">
+    <textarea class="form-control" rows="3" name="{{ key }}" id="{{ id }}_{{ key }}" placeholder="partner.example, user@example.org"{% if ro %} disabled{% endif %}>{{ attribute(entries, key) }}</textarea>
+    <small class="text-muted d-block mb-1">{{ attribute(lang.mail_policy, 'entries_info_' ~ side) }}</small>
+    {% if groups %}
+    {% if not ro %}<input type="hidden" name="{{ key }}_groups" value="">{% endif %}
+    <select data-live-search="true" data-width="100%" name="{{ key }}_groups" class="form-control mail-policy-groups" multiple title="{{ lang.mail_policy.groups }}"{% if ro %} disabled{% endif %}>
+      {% for group in groups %}
+      <option value="{{ group.id }}" data-domain="{{ group.domain }}"{% if group.id ~ '' in attribute(listed, key) %} selected{% endif %}>{{ group.name }}{% if group.address %} ({{ group.address }}){% endif %}</option>
+      {% endfor %}
+    </select>
+    {% endif %}
+  </div>
+</div>
+{% endfor %}
+{% endfor %}
+<div class="row mb-2">
+  <label class="control-label col-sm-2{{ label_class }}" for="{{ id }}_reject_text">{{ lang.mail_policy.reject_text }}</label>
+  <div class="col-sm-10">
+    <input type="text" class="form-control" name="reject_text" id="{{ id }}_reject_text" maxlength="200" value="{{ policy.reject_text|default('') }}"{% if ro %} disabled{% endif %}>
+    <small class="text-muted d-block">{{ lang.mail_policy.reject_text_info }}</small>
+  </div>
+</div>
+<legend class="fs-5 mt-4"><i class="bi bi-people"></i> {{ lang.mail_policy.assign }}</legend><hr>
+<p class="text-muted small">{{ lang.mail_policy.assign_info }}</p>
+<div class="row mb-2">
+  <label class="control-label col-sm-2{{ label_class }}" for="{{ id }}_mailboxes">{{ lang.mail_policy.mailboxes }}</label>
+  <div class="col-sm-10">
+    {% if not ro %}<input type="hidden" name="mailboxes" value="">{% endif %}
+    <select data-live-search="true" data-width="100%" name="mailboxes" id="{{ id }}_mailboxes" class="form-control mail-policy-mailboxes" multiple title="{{ lang.mail_policy.mailboxes }}"{% if ro %} disabled{% endif %}>
+      {% for mailbox in mailboxes %}
+      <option value="{{ mailbox }}" data-domain="{{ mailbox|split('@')|last }}"{% if mailbox in policy.mailboxes|default([]) %} selected{% endif %}>{{ mailbox }}</option>
+      {% endfor %}
+    </select>
+  </div>
+</div>
+{% if groups %}
+<div class="row mb-2">
+  <label class="control-label col-sm-2{{ label_class }}" for="{{ id }}_groups">{{ lang.mail_policy.groups }}</label>
+  <div class="col-sm-10">
+    {% if not ro %}<input type="hidden" name="groups" value="">{% endif %}
+    <select data-live-search="true" data-width="100%" name="groups" id="{{ id }}_groups" class="form-control mail-policy-groups" multiple title="{{ lang.mail_policy.groups }}"{% if ro %} disabled{% endif %}>
+      {% for group in groups %}
+      <option value="{{ group.id }}" data-domain="{{ group.domain }}"{% if group.id in policy.groups|default([]) %} selected{% endif %}>{{ group.name }}{% if group.address %} ({{ group.address }}){% endif %}</option>
+      {% endfor %}
+    </select>
+  </div>
+</div>
+{% endif %}

data/web/templates/edit/mail-policy.twig

@@ -0,0 +1,46 @@
+{% extends 'edit.twig' %}
+
+{% block inner_content %}
+{% if result %}
+{% set ro = not result.can_edit %}
+<h4>{{ lang.mail_policy.policy }}: {{ result.name }}</h4>
+<form data-id="edit_mail_policy" class="form-horizontal" role="form" method="post" autocapitalize="none" autocorrect="off">
+  <input type="hidden" value="0" name="active">
+  <div class="row mb-2">
+    <label class="control-label col-sm-2" for="mail_policy_domain">{{ lang.mail_policy.domain }}</label>
+    <div class="col-sm-10">
+      <input type="text" class="form-control" id="mail_policy_domain" value="{{ result.domain }}" disabled>
+    </div>
+  </div>
+  <div class="row mb-2">
+    <label class="control-label col-sm-2" for="mail_policy_name">{{ lang.mail_policy.name }}</label>
+    <div class="col-sm-10">
+      <input type="text" class="form-control" name="name" id="mail_policy_name" value="{{ result.name }}" maxlength="100" required{% if ro %} disabled{% endif %}>
+    </div>
+  </div>
+  <div class="row mb-2">
+    <label class="control-label col-sm-2" for="mail_policy_description">{{ lang.mail_policy.description }}</label>
+    <div class="col-sm-10">
+      <input type="text" class="form-control" name="description" id="mail_policy_description" value="{{ result.description }}" maxlength="255"{% if ro %} disabled{% endif %}>
+    </div>
+  </div>
+  {% include 'edit/mail-policy-fields.twig' with {'policy': result, 'id': 'mail_policy', 'groups': mail_policy_groups, 'mailboxes': mailboxes, 'ro': ro, 'label_class': ''} %}
+  <div class="row mb-4">
+    <div class="offset-sm-2 col-sm-10">
+      <div class="form-check">
+        <label><input type="checkbox" class="form-check-input" value="1" name="active"{% if result.active == 1 %} checked{% endif %}{% if ro %} disabled{% endif %}> {{ lang.mailbox.active }}</label>
+      </div>
+    </div>
+  </div>
+  {% if not ro %}
+  <div class="row">
+    <div class="offset-sm-2 col-sm-10">
+      <button class="btn btn-xs-lg d-block d-sm-inline btn-success" data-action="edit_selected" data-id="edit_mail_policy" data-item="{{ result.id }}" data-api-url='edit/mail-policy' data-api-attr='{}' href="#"><i class="bi bi-check-lg"></i> {{ lang.admin.save }}</button>
+    </div>
+  </div>
+  {% endif %}
+</form>
+{% else %}
+  {{ parent() }}
+{% endif %}
+{% endblock %}

data/web/templates/mailbox.twig

@@ -36,10 +36,20 @@
     {% if acl.mailbox_groups == 1 %}
     <li class="nav-item" role="presentation"><button class="nav-link" aria-selected="false" aria-controls="tab-groups" role="tab" data-bs-toggle="tab" data-bs-target="#tab-groups">{{ lang.groups.groups }}</button></li>
     {% endif %}
+    {% if mailcow_cc_role == 'admin' %}
+    <li class="nav-item dropdown">
+      <a class="nav-link dropdown-toggle" data-bs-toggle="dropdown" href="#">{{ lang.mailbox.policies }}</a>
+      <ul class="dropdown-menu">
+        <li role="presentation"><button class="dropdown-item" aria-selected="false" aria-controls="tab-tls-policy" role="tab" data-bs-toggle="tab" data-bs-target="#tab-tls-policy">{{ lang.mailbox.policies_tls }}</button></li>
+        <li role="presentation"><button class="dropdown-item" aria-selected="false" aria-controls="tab-mail-policies" role="tab" data-bs-toggle="tab" data-bs-target="#tab-mail-policies">{{ lang.mailbox.policies_mail }}</button></li>
+      </ul>
+    </li>
+    {% elseif acl.mail_policies == 1 %}
+    <li class="nav-item" role="presentation"><button class="nav-link" aria-selected="false" aria-controls="tab-mail-policies" role="tab" data-bs-toggle="tab" data-bs-target="#tab-mail-policies">{{ lang.mail_policy.mail_policies }}</button></li>
+    {% endif %}
     <li class="nav-item" role="presentation"><button class="nav-link" aria-selected="false" aria-controls="tab-syncjobs" role="tab" data-bs-toggle="tab" data-bs-target="#tab-syncjobs">{{ lang.syncjobs.sync_jobs }}</button></li>
     <li class="nav-item" role="presentation"><button class="nav-link" aria-selected="false" aria-controls="tab-filters" role="tab" data-bs-toggle="tab" data-bs-target="#tab-filters">{{ lang.mailbox.filters }}</button></li>
     <li class="nav-item" role="presentation"><button class="nav-link" aria-selected="false" aria-controls="tab-bcc" role="tab" data-bs-toggle="tab" data-bs-target="#tab-bcc">{{ lang.mailbox.address_rewriting }}</button></li>
-    <li class="nav-item" role="presentation"{% if mailcow_cc_role != 'admin' %} class="d-none"{% endif %}><button class="nav-link" aria-selected="false" aria-controls="tab-tls-policy" role="tab" data-bs-toggle="tab" data-bs-target="#tab-tls-policy">{{ lang.mailbox.tls_policy_maps }}</button></li>
   </ul>
 
   <div class="row">
@@ -59,6 +69,9 @@
         {% if acl.mailbox_groups == 1 %}
         {% include 'mailbox/tab-groups.twig' %}
         {% endif %}
+        {% if acl.mail_policies == 1 %}
+        {% include 'mailbox/tab-mail-policies.twig' %}
+        {% endif %}
         {% include 'mailbox/tab-syncjobs.twig' %}
         {% include 'mailbox/tab-filters.twig' %}
         {% include 'mailbox/tab-bcc.twig' %}
@@ -75,6 +88,7 @@
   var lang = {{ lang_mailbox|raw }};
   lang.syncjobs = {{ lang_syncjobs|raw }};
   lang.groups = {{ lang_groups|raw }};
+  lang.mail_policy = {{ lang_mail_policy|raw }};
   var lang_rl = {{ lang_rl|raw }};
   var lang_edit = {{ lang_edit|raw }};
   var lang_datatables = {{ lang_datatables|raw }};

data/web/templates/mailbox/tab-mail-policies.twig

@@ -0,0 +1,54 @@
+<div class="tab-pane fade" id="tab-mail-policies" role="tabpanel" aria-labelledby="tab-mail-policies">
+  <div class="card mb-4">
+    <div class="card-header d-flex fs-5">
+      <button class="btn d-md-none flex-grow-1 text-start" data-bs-target="#collapse-tab-mail-policies" data-bs-toggle="collapse" aria-controls="collapse-tab-mail-policies">
+        {{ lang.mail_policy.mail_policies }} <span class="badge bg-info table-lines"></span>
+      </button>
+      <span class="d-none d-md-block">{{ lang.mail_policy.mail_policies }} <span class="badge bg-info table-lines"></span></span>
+      <div class="btn-group ms-auto d-flex">
+        <button class="btn btn-xs btn-secondary refresh_table" data-table="mail_policy_table">{{ lang.admin.refresh }}</button>
+      </div>
+    </div>
+    <div id="collapse-tab-mail-policies" class="card-body collapse" data-bs-parent="#mail-content">
+      <p class="text-muted">{{ lang.mail_policy.info }}</p>
+      <table id="mail_policy_table" class="table table-striped dt-responsive w-100"></table>
+      <div class="mass-actions-mailbox mt-4">
+        <div class="btn-group">
+          <a class="btn btn-sm btn-xs-half d-block d-sm-inline btn-secondary" id="toggle_multi_select_all" data-id="mail_policy" href="#"><i class="bi bi-check-all"></i> {{ lang.mailbox.toggle_all }}</a>
+          <a class="btn btn-sm btn-xs-half d-block d-sm-inline btn-secondary dropdown-toggle" data-bs-toggle="dropdown" href="#">{{ lang.mailbox.quick_actions }}</a>
+          <ul class="dropdown-menu">
+            <li><a class="dropdown-item" data-action="edit_selected" data-id="mail_policy" data-api-url='edit/mail-policy' data-api-attr='{"active":"1"}' href="#">{{ lang.mailbox.activate }}</a></li>
+            <li><a class="dropdown-item" data-action="edit_selected" data-id="mail_policy" data-api-url='edit/mail-policy' data-api-attr='{"active":"0"}' href="#">{{ lang.mailbox.deactivate }}</a></li>
+            <li><hr class="dropdown-divider"></li>
+            <li><a class="dropdown-item" data-action="delete_selected" data-id="mail_policy" data-api-url='delete/mail-policy' href="#">{{ lang.mailbox.remove }}</a></li>
+          </ul>
+          <a class="btn btn-sm d-block d-sm-inline btn-success" href="#" data-bs-toggle="modal" data-bs-target="#addMailPolicyModal"><i class="bi bi-plus-lg"></i> {{ lang.mail_policy.add }}</a>
+        </div>
+      </div>
+
+      {# Test a rule: would the mail be accepted? Filled by js/site/mail-policy.js #}
+      <div class="card mt-4">
+        <div class="card-header">{{ lang.mail_policy.test }}</div>
+        <div class="card-body">
+          <p class="text-muted small">{{ lang.mail_policy.test_info }}</p>
+          <form class="row g-2 align-items-center" id="mail_policy_test" autocomplete="off">
+            <div class="col-12 col-md-4">
+              <input type="email" class="form-control" id="mail_policy_test_sender" placeholder="{{ lang.mail_policy.test_sender }}" aria-label="{{ lang.mail_policy.test_sender }}">
+            </div>
+            <div class="col-12 col-md-4">
+              <input type="email" class="form-control" id="mail_policy_test_recipient" placeholder="{{ lang.mail_policy.test_recipient }}" aria-label="{{ lang.mail_policy.test_recipient }}" required>
+            </div>
+            <div class="col-12 col-md-4 d-flex align-items-center">
+              <div class="form-check me-3">
+                <input class="form-check-input" type="checkbox" id="mail_policy_test_login" checked>
+                <label class="form-check-label" for="mail_policy_test_login">{{ lang.mail_policy.test_logged_in }}</label>
+              </div>
+              <button type="submit" class="btn btn-sm btn-secondary ms-auto"><i class="bi bi-play"></i> {{ lang.mail_policy.test_run }}</button>
+            </div>
+          </form>
+          <div id="mail_policy_test_result" class="mt-3"></div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>

data/web/templates/modals/mail_policy.twig

@@ -0,0 +1,50 @@
+<div class="modal fade" id="addMailPolicyModal" tabindex="-1" role="dialog" aria-hidden="true">
+  <div class="modal-dialog modal-xl">
+    <div class="modal-content">
+      <div class="modal-header">
+        <h3 class="modal-title">{{ lang.mail_policy.add }}</h3>
+        <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
+      </div>
+      <div class="modal-body">
+        <form class="form-horizontal" role="form" data-id="add_mail_policy" autocapitalize="none" autocorrect="off">
+          <input type="hidden" value="0" name="active">
+          <div class="row mb-2">
+            <label class="control-label col-sm-2 text-sm-end" for="add_mail_policy_domain">{{ lang.mail_policy.domain }}</label>
+            <div class="col-sm-10">
+              <select data-live-search="true" name="domain" id="add_mail_policy_domain" class="form-control mail-policy-domain-select" required>
+                {% for domain in domains %}
+                <option>{{ domain }}</option>
+                {% endfor %}
+              </select>
+            </div>
+          </div>
+          <div class="row mb-2">
+            <label class="control-label col-sm-2 text-sm-end" for="add_mail_policy_name">{{ lang.mail_policy.name }}</label>
+            <div class="col-sm-10">
+              <input type="text" class="form-control" name="name" id="add_mail_policy_name" maxlength="100" required>
+            </div>
+          </div>
+          <div class="row mb-2">
+            <label class="control-label col-sm-2 text-sm-end" for="add_mail_policy_description">{{ lang.mail_policy.description }}</label>
+            <div class="col-sm-10">
+              <input type="text" class="form-control" name="description" id="add_mail_policy_description" maxlength="255">
+            </div>
+          </div>
+          {% include 'edit/mail-policy-fields.twig' with {'policy': {}, 'id': 'add_mail_policy', 'groups': mail_policy_groups, 'mailboxes': mailboxes, 'ro': false, 'label_class': ' text-sm-end'} %}
+          <div class="row mb-2">
+            <div class="offset-sm-2 col-sm-10">
+              <div class="form-check">
+                <label><input type="checkbox" class="form-check-input" value="1" name="active" checked> {{ lang.mailbox.active }}</label>
+              </div>
+            </div>
+          </div>
+          <div class="row">
+            <div class="offset-sm-2 col-sm-10">
+              <button class="btn btn-xs-lg d-block d-sm-inline btn-success" data-action="add_item" data-id="add_mail_policy" data-api-url='add/mail-policy' data-api-attr='{}' href="#">{{ lang.admin.add }}</button>
+            </div>
+          </div>
+        </form>
+      </div>
+    </div>
+  </div>
+</div>

data/web/templates/modals/mailbox.twig

@@ -1362,3 +1362,6 @@
 {% if acl.mailbox_groups == 1 %}
 {% include "modals/mailbox_group.twig" %}
 {% endif %}
+{% if acl.mail_policies == 1 %}
+{% include "modals/mail_policy.twig" %}
+{% endif %}

docker-compose.yml

@@ -1,5 +1,5 @@
 # Version of the database schema
-x-db-version: &db_version DB_VERSION=02112026_1600
+x-db-version: &db_version DB_VERSION=07112026_1800
 
 services:
 
@@ -348,7 +348,7 @@ services:
             - dovecot
 
     postfix-mailcow:
-      image: ghcr.io/mailcow/postfix:3.10.12-1
+      image: ghcr.io/mailcow/postfix:3.10.12-2
       depends_on:
         mysql-mailcow:
           condition: service_started
@@ -375,6 +375,7 @@ services:
         - REDISPASS=${REDISPASS}
         - MAILCOW_HOSTNAME=${MAILCOW_HOSTNAME}
         - SPAMHAUS_DQS_KEY=${SPAMHAUS_DQS_KEY:-}
+        - *db_version
       cap_add:
         - NET_BIND_SERVICE
       ports:

tests/php/MailPolicy/Service/PolicyEngineTest.php

@@ -0,0 +1,296 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\Tests\MailPolicy\Service;
+
+use Mailcow\MailPolicy\Model\Policy;
+use Mailcow\MailPolicy\Service\PolicyEngine;
+use Mailcow\Tests\Support\FakeMailPolicyLookup;
+use PHPUnit\Framework\TestCase;
+
+class PolicyEngineTest extends TestCase
+{
+    private FakeMailPolicyLookup $lookup;
+    private PolicyEngine $engine;
+
+    protected function setUp(): void
+    {
+        $this->lookup = new FakeMailPolicyLookup();
+        $this->lookup->domains = ['firma.de', 'tochter.de'];
+        $this->lookup->aliasDomains = ['firma.com' => 'firma.de'];
+        $this->lookup->mailboxes = [
+            'azubi@firma.de' => 'firma.de',
+            'kollege@firma.de' => 'firma.de',
+            'chef@firma.de' => 'firma.de',
+            'info@firma.de' => 'firma.de',
+            'andere@tochter.de' => 'tochter.de',
+        ];
+        $this->lookup->groups = [
+            7 => ['address' => 'azubis@firma.de', 'members' => ['azubi@firma.de']],
+            8 => ['address' => 'vorstand@firma.de', 'members' => ['chef@firma.de']],
+        ];
+        $this->engine = new PolicyEngine($this->lookup);
+    }
+
+    private static function policy(int $id, array $values): Policy
+    {
+        $policy = new Policy();
+        $policy->id = $id;
+        $policy->domain = 'firma.de';
+        $policy->name = 'policy ' . $id;
+        foreach ($values as $property => $value) {
+            $policy->$property = $value;
+        }
+        return $policy;
+    }
+
+    /** [allowed, side] of a check */
+    private function check(string $sender, string $recipient, string $login = '', int $port = 587, string $helo = ''): array
+    {
+        $decision = $this->engine->check($sender, $recipient, $login, $port, $helo);
+        return [$decision->allowed, $decision->side];
+    }
+
+    public function testWithoutPoliciesEverythingPasses(): void
+    {
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'azubi@firma.de'));
+        $this->assertSame('DUNNO', $this->engine->check('azubi@firma.de', 'x@extern.example', 'azubi@firma.de')->action());
+    }
+
+    public function testSendOnlyInternalWithAllowedAndBlockedEntries(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(1, [
+            'sendMode' => 'internal', 'sendAllow' => ['partner.de', 'kunde@extern.example'], 'sendBlock' => ['chef@firma.de'],
+        ])];
+
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'kollege@firma.de', 'azubi@firma.de'));
+        // alias domain and sub-address are internal
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'Kollege+x@firma.com', 'azubi@firma.de'));
+        $this->assertSame([false, 'send'], $this->check('azubi@firma.de', 'x@extern.example', 'azubi@firma.de'));
+        // another domain of the same mailcow is not internal
+        $this->assertSame([false, 'send'], $this->check('azubi@firma.de', 'andere@tochter.de', 'azubi@firma.de'));
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'jemand@partner.de', 'azubi@firma.de'));
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'kunde@extern.example', 'azubi@firma.de'));
+        $this->assertSame([false, 'send'], $this->check('azubi@firma.de', 'chef@firma.de', 'azubi@firma.de'));
+        // the rules belong to the login: without it nothing is sent as azubi
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'x@extern.example'));
+    }
+
+    public function testSendOnlyListedRecipientsThroughAGroup(): void
+    {
+        $this->lookup->groupPolicies[7] = [self::policy(2, ['sendMode' => 'list', 'sendAllow' => ['group:8']])];
+
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'vorstand@firma.de', 'azubi@firma.de'));
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'chef@firma.de', 'azubi@firma.de'));
+        $this->assertSame([false, 'send'], $this->check('azubi@firma.de', 'kollege@firma.de', 'azubi@firma.de'));
+        // not a member: no rule
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'x@extern.example', 'kollege@firma.de'));
+    }
+
+    public function testSendingAsAnotherMailboxAppliesItsPolicyToo(): void
+    {
+        $this->lookup->mailboxPolicies['info@firma.de'] = [self::policy(3, ['sendMode' => 'internal'])];
+
+        $this->assertSame([false, 'send'], $this->check('info@firma.de', 'x@extern.example', 'chef@firma.de'));
+        $this->assertSame([true, ''], $this->check('chef@firma.de', 'x@extern.example', 'chef@firma.de'));
+    }
+
+    public function testReceiveOnlyInternalCannotBeForged(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(4, ['receiveMode' => 'internal', 'receiveAllow' => ['partner.de'],
+            'receiveBlock' => ['chef@firma.de']])];
+
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'azubi@firma.de', '', 25));
+        // a forged internal sender is external
+        $this->assertSame([false, 'receive'], $this->check('kollege@firma.de', 'azubi@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'azubi+news@firma.com', 'kollege@firma.de'));
+        $this->assertSame([false, 'receive'], $this->check('andere@tochter.de', 'azubi@firma.de', 'andere@tochter.de'));
+        // an external domain on the list is compared with the envelope sender
+        $this->assertSame([true, ''], $this->check('jemand@partner.de', 'azubi@firma.de', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('chef@firma.de', 'azubi@firma.de', 'chef@firma.de'));
+        // null sender (bounces) is external
+        $this->assertSame([false, 'receive'], $this->check('', 'azubi@firma.de', '', 25));
+    }
+
+    public function testListedLocalSendersMustBeLoggedIn(): void
+    {
+        $this->lookup->mailboxPolicies['chef@firma.de'] = [self::policy(5, ['receiveMode' => 'list',
+            'receiveAllow' => ['kollege@firma.de', 'group:7', 'tochter.de']])];
+
+        $this->assertSame([false, 'receive'], $this->check('kollege@firma.de', 'chef@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'chef@firma.de', 'kollege@firma.de'));
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'chef@firma.de', 'azubi@firma.de'));
+        $this->assertSame([false, 'receive'], $this->check('azubi@firma.de', 'chef@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('andere@tochter.de', 'chef@firma.de', 'andere@tochter.de'));
+        $this->assertSame([false, 'receive'], $this->check('andere@tochter.de', 'chef@firma.de', '', 25));
+    }
+
+    public function testGroupAddressAndMembersAsRecipients(): void
+    {
+        $this->lookup->groupPolicies[8] = [self::policy(6, ['receiveMode' => 'internal', 'receiveBlock' => ['group:7']])];
+
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'vorstand@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'vorstand@firma.de', 'kollege@firma.de'));
+        // the policy of a group applies to its members as well
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'chef@firma.de', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('azubi@firma.de', 'chef@firma.de', 'azubi@firma.de'));
+    }
+
+    public function testInternalFlagOfAliasesAndGroups(): void
+    {
+        $this->lookup->aliases['team@firma.de'] = ['domain' => 'firma.de', 'internal' => true];
+
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'team@firma.de', '', 25));
+        // the old rspamd rule let forged senders of the domain pass
+        $this->assertSame([false, 'receive'], $this->check('kollege@firma.de', 'team@firma.com', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'team@firma.de', 'kollege@firma.de'));
+        $this->assertSame([false, 'receive'], $this->check('andere@tochter.de', 'team@firma.de', 'andere@tochter.de'));
+    }
+
+    public function testTheStrictestPolicyWins(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(9, ['sendMode' => 'all'])];
+        $this->lookup->groupPolicies[7] = [self::policy(10, ['sendMode' => 'internal', 'rejectText' => 'Azubis senden nur intern'])];
+
+        $decision = $this->engine->check('azubi@firma.de', 'x@extern.example', 'azubi@firma.de', 587);
+        $this->assertSame(['send', 10, '550 5.7.1 Azubis senden nur intern'], [$decision->side, $decision->policy->id, $decision->action()]);
+    }
+
+    public function testDefaultTextsAndOwnDeliveries(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(11, ['sendMode' => 'internal', 'receiveMode' => 'internal'])];
+
+        $this->assertSame('550 5.7.1 Sending to this recipient is not allowed by the mail policy of the sender',
+            $this->engine->check('azubi@firma.de', 'x@extern.example', 'azubi@firma.de', 587)->action());
+        $this->assertSame('550 5.7.1 This recipient does not accept mail from this sender',
+            $this->engine->check('x@extern.example', 'azubi@firma.de', '', 25)->action());
+        // quarantine release (590) and BCC/archive copies (591) are not checked
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'azubi@firma.de', '', 590));
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'azubi@firma.de', '', 591));
+    }
+
+    public function testDovecotSubmissionsCountAsTheMailbox(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(12, ['sendMode' => 'internal'])];
+        $this->lookup->mailboxPolicies['chef@firma.de'] = [self::policy(13, ['receiveMode' => 'internal'])];
+        $this->lookup->aliases['team@firma.de'] = ['domain' => 'firma.de', 'internal' => true];
+
+        // a Sieve redirect of azubi to an external address follows its send rules
+        $this->assertSame([false, 'send'], $this->check('azubi+x@firma.de', 'x@extern.example', '', 588));
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'chef@firma.de', '', 588));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'team@firma.de', '', 588));
+        // other senders are checked like mail from outside
+        $this->assertSame([false, 'receive'], $this->check('quota-warning@localhost', 'chef@firma.de', '', 588));
+        // the quota warning copies of Dovecot carry the address of the mailbox over its quota
+        $this->assertSame([true, ''], $this->check('azubi@firma.de', 'x@extern.example', '', 588, 'quotanotification'));
+        // on other ports the sender address is no login
+        $this->assertSame([false, 'receive'], $this->check('kollege@firma.de', 'team@firma.de', '', 25));
+    }
+
+    public function testDovecotMailWithoutMailboxSender(): void
+    {
+        // bounces redirected with the null sender, notifications of other senders: local recipients only while
+        // a policy restricts sending, as the sending mailbox is unknown
+        $this->assertSame([true, ''], $this->check('', 'x@extern.example', '', 588));
+        $this->lookup->sendRules = true;
+        $this->assertSame([false, 'send'], $this->check('', 'x@extern.example', '', 588));
+        $this->assertSame([false, 'send'], $this->check('irgendwer@nirgends.example', 'x@extern.example', '', 588));
+        $this->assertSame([true, ''], $this->check('', 'kollege@firma.com', '', 588));
+        // local recipients: receive rules as for mail from outside
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(14, ['sendMode' => 'internal', 'receiveMode' => 'internal'])];
+        $this->assertSame([false, 'receive'], $this->check('', 'azubi@firma.de', '', 588));
+        // SOGo reminders log in with the Dovecot master user
+        $this->assertSame([false, 'send'], $this->check('azubi@firma.de', 'x@extern.example', 'abc@mailcow.local', 588));
+        $this->assertSame([false, 'send'], $this->check('', 'x@extern.example', 'abc@mailcow.local', 588));
+    }
+
+    public function testRecipientsAreComparedAsPostfixDeliversThem(): void
+    {
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(15, ['receiveMode' => 'internal'])];
+
+        // trailing dot and quotes are dropped by Postfix
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'Azubi@Firma.de.', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', '"azubi+a b"@firma.com', '', 25));
+        // routes through another address are refused, Postfix would deliver them to the routed address
+        foreach (['azubi@firma.de@localhost', 'azubi%firma.de@localhost', 'firma.de!azubi@localhost.localdomain', 'x@extern.example@localhost',
+            'azubi%firma.de@[192.0.2.1]', 'abuse'] as $recipient) {
+            $this->assertSame([false, 'address'], $this->check('x@extern.example', $recipient, '', 25), $recipient);
+        }
+        // in other domains %, ! and @ in the local part are ordinary characters
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'a!b@extern.example', 'kollege@firma.de'));
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'sales%x@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'postmaster', '', 25));
+        $this->assertSame('550 5.7.1 This form of the recipient address is not allowed by the mail policy',
+            $this->engine->check('azubi@firma.de', 'x%extern.example@localhost', 'azubi@firma.de', 587)->action());
+    }
+
+    public function testSendersAreComparedAsPostfixResolvesThem(): void
+    {
+        $this->lookup->mailboxPolicies['kollege@firma.de'] = [self::policy(16, ['sendBlock' => ['konkurrenz.example']])];
+        $this->lookup->mailboxPolicies['info@firma.de'] = [self::policy(17, ['sendMode' => 'internal'])];
+
+        $this->assertSame([false, 'send'], $this->check('kollege@firma.de', 'x@konkurrenz.example.', 'kollege@firma.de'));
+        // sending as info@ with a trailing dot keeps the policy of info@
+        $this->assertSame([false, 'send'], $this->check('Info@firma.de.', 'x@extern.example', 'chef@firma.de'));
+    }
+
+    public function testTemporaryAliasesFollowTheirOwner(): void
+    {
+        $this->lookup->temporaryAliases['einmal.xyz@firma.de'] = 'azubi@firma.de';
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [self::policy(18, ['receiveMode' => 'internal'])];
+
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'einmal.xyz@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'einmal.xyz@firma.de', 'kollege@firma.de'));
+    }
+
+    public function testInternalFlagFollowsThePostfixLookup(): void
+    {
+        // an alias of its own in an alias domain; senders of the target domain are internal
+        $this->lookup->aliases['team2@firma.com'] = ['domain' => 'firma.com', 'internal' => true];
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'team2@firma.com', '', 25));
+        $this->assertSame([true, ''], $this->check('kollege@firma.de', 'team2@firma.com', 'kollege@firma.de'));
+        // the full address first, then without +tag
+        $this->lookup->aliases['team+ext@firma.de'] = ['domain' => 'firma.de', 'internal' => true];
+        $this->lookup->aliases['team@firma.de'] = ['domain' => 'firma.de', 'internal' => false];
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'team+ext@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'team+other@firma.de', '', 25));
+        // an internal catch-all alias covers the whole domain, also through its alias domain
+        $this->lookup->internalCatchAlls = ['tochter.de'];
+        $this->lookup->aliasDomains['tochter.com'] = 'tochter.de';
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'andere@tochter.de', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'unbekannt@tochter.com', '', 25));
+        $this->assertSame([true, ''], $this->check('andere@tochter.de', 'unbekannt@tochter.de', 'andere@tochter.de'));
+    }
+
+    public function testAddressesAreComparedInTheirStoredSpelling(): void
+    {
+        // MySQL ignores accents: Postfix delivers chéf@ to chef@ and töchter.de to tochter.de
+        $this->lookup->spellings = ['chéf@firma.de' => 'chef@firma.de', 'töchter.de' => 'tochter.de', 'köllege@firma.de' => 'kollege@firma.de'];
+        $this->lookup->mailboxPolicies['kollege@firma.de'] = [self::policy(20, ['sendBlock' => ['chef@firma.de', 'tochter.de']])];
+        $this->lookup->mailboxPolicies['chef@firma.de'] = [self::policy(21, ['receiveBlock' => ['kollege@firma.de']])];
+
+        $this->assertSame([false, 'send'], $this->check('kollege@firma.de', 'chéf@firma.de', 'kollege@firma.de'));
+        $this->assertSame([false, 'send'], $this->check('kollege@firma.de', 'x@töchter.de', 'kollege@firma.de'));
+        $this->assertSame([false, 'receive'], $this->check('köllege@firma.de', 'chef@firma.de', '', 25));
+    }
+
+    public function testTaggedAliasThroughAnAliasDomain(): void
+    {
+        // Postfix maps chef@firma.com to chef@firma.de and looks up chef+intern@firma.de again
+        $this->lookup->aliases['chef+intern@firma.de'] = ['domain' => 'firma.de', 'internal' => true];
+
+        $this->assertSame([false, 'receive'], $this->check('x@extern.example', 'chef+intern@firma.com', '', 25));
+        $this->assertSame([true, ''], $this->check('x@extern.example', 'chef+other@firma.com', '', 25));
+    }
+
+    public function testBlockEntriesAlsoMatchTheEnvelopeSender(): void
+    {
+        $this->lookup->mailboxPolicies['chef@firma.de'] = [self::policy(19, ['receiveBlock' => ['kollege@firma.de', 'group:7', 'tochter.de']])];
+
+        $this->assertSame([false, 'receive'], $this->check('kollege@firma.de', 'chef@firma.de', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('azubi@firma.de', 'chef@firma.de', '', 25));
+        $this->assertSame([false, 'receive'], $this->check('andere@tochter.de', 'chef@firma.de', '', 25));
+        $this->assertSame([true, ''], $this->check('info@firma.de', 'chef@firma.de', '', 25));
+    }
+}

tests/php/MailPolicy/Service/PolicyServiceTest.php

@@ -0,0 +1,226 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\Tests\MailPolicy\Service;
+
+use Mailcow\Core\AccessDenied;
+use Mailcow\Core\Context;
+use Mailcow\Core\UserError;
+use Mailcow\MailPolicy\Model\Policy;
+use Mailcow\MailPolicy\Repository\PolicyRepository;
+use Mailcow\MailPolicy\Service\PolicyEngine;
+use Mailcow\MailPolicy\Service\PolicyService;
+use Mailcow\Tests\Support\FakeContext;
+use Mailcow\Tests\Support\FakeMailPolicyLookup;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class PolicyServiceTest extends TestCase
+{
+    private PolicyRepository&MockObject $repo;
+    private FakeMailPolicyLookup $lookup;
+    /** @var Policy[] saved policies */
+    private array $saved = [];
+    private int $groupLookups = 0;
+
+    protected function setUp(): void
+    {
+        $this->repo = $this->createMock(PolicyRepository::class);
+        $this->repo->method('isDomain')->willReturnCallback(fn(string $domain): bool => in_array($domain, ['firma.de', 'tochter.de'], true));
+        $this->repo->method('mailboxDomain')->willReturnCallback(fn(string $username): ?string =>
+            ['azubi@firma.de' => 'firma.de', 'chef@firma.de' => 'firma.de', 'andere@tochter.de' => 'tochter.de'][$username] ?? null);
+        $this->repo->method('groupDomain')->willReturnCallback(function (int $id): ?string {
+            $this->groupLookups++;
+            return [7 => 'firma.de', 9 => 'tochter.de'][$id] ?? null;
+        });
+        $this->repo->method('groupsIn')->willReturn([['id' => 7, 'name' => 'Azubis', 'domain' => 'firma.de', 'address' => null]]);
+        $this->repo->method('save')->willReturnCallback(function (Policy $policy): int {
+            $policy->id ??= 1;
+            $this->saved[] = clone $policy;
+            return $policy->id;
+        });
+        $this->lookup = new FakeMailPolicyLookup();
+        $this->lookup->domains = ['firma.de', 'tochter.de'];
+        $this->lookup->mailboxes = ['azubi@firma.de' => 'firma.de', 'chef@firma.de' => 'firma.de'];
+    }
+
+    private function service(?Context $context = null): PolicyService
+    {
+        return new PolicyService($this->repo, new PolicyEngine($this->lookup), $context ?? FakeContext::admin());
+    }
+
+    private function stored(array $values = []): Policy
+    {
+        $policy = new Policy();
+        $policy->id = 3;
+        $policy->domain = 'firma.de';
+        $policy->name = 'Azubis';
+        $policy->sendAllow = ['partner.de', 'group:7'];
+        foreach ($values as $property => $value) {
+            $policy->$property = $value;
+        }
+        return $policy;
+    }
+
+    private function expectUserError(string|array $msg, callable $call): void
+    {
+        try {
+            $call();
+            $this->fail('UserError ' . json_encode($msg) . ' expected');
+        } catch (UserError $e) {
+            $this->assertSame($msg, $e->msg());
+        }
+    }
+
+    public function testCreateNormalizesTheInput(): void
+    {
+        $policy = $this->service()->create([
+            'domain' => 'Firma.de', 'name' => 'Azubis', 'description' => 'Nur intern', 'active' => ['0', '1'],
+            'send_mode' => 'internal', 'send_allow' => "@Partner.de\nkunde@extern.example, partner.de", 'send_allow_groups' => ['', '7'],
+            'send_block' => '', 'receive_mode' => 'list', 'receive_allow' => ['group:7'], 'reject_text' => 'Nur intern erlaubt',
+            'mailboxes' => ['', 'Azubi@firma.de'], 'groups' => ['7'],
+        ]);
+
+        $this->assertSame([
+            'domain' => 'firma.de', 'name' => 'Azubis', 'description' => 'Nur intern', 'send_mode' => 'internal',
+            'send_allow' => ['partner.de', 'kunde@extern.example', 'group:7'], 'send_block' => [], 'receive_mode' => 'list',
+            'receive_allow' => ['group:7'], 'receive_block' => [], 'reject_text' => 'Nur intern erlaubt', 'active' => 1,
+            'mailboxes' => ['azubi@firma.de'], 'groups' => [7],
+        ], array_intersect_key($policy->toArray(), array_flip(['domain', 'name', 'description', 'send_mode', 'send_allow', 'send_block',
+            'receive_mode', 'receive_allow', 'receive_block', 'reject_text', 'active', 'mailboxes', 'groups'])));
+        $this->assertCount(1, $this->saved);
+    }
+
+    public function testUpdateKeepsMissingValuesAndReplacesListGroups(): void
+    {
+        $this->repo->method('find')->willReturn($this->stored());
+
+        $policy = $this->service()->update(3, ['description' => 'neu']);
+        $this->assertSame(['neu', ['partner.de', 'group:7']], [$policy->description, $policy->sendAllow]);
+
+        // the UI sends the groups apart: they replace the group entries, the other entries stay
+        $this->repo->method('find')->willReturn($this->stored());
+        $this->assertSame(['partner.de'], $this->service()->update(3, ['send_allow_groups' => ''])->sendAllow);
+    }
+
+    public static function invalidInput(): array
+    {
+        return [
+            'empty name' => [['name' => ''], 'mail_policy_name_invalid'],
+            'long name' => [['name' => str_repeat('a', 101)], 'mail_policy_name_invalid'],
+            'mode' => [['send_mode' => 'nobody'], 'mail_policy_mode_invalid'],
+            'domain without dot' => [['send_allow' => 'localhost'], ['mail_policy_entry_invalid', 'localhost']],
+            'address' => [['receive_block' => 'a@@b.de'], ['mail_policy_entry_invalid', 'a@@b.de']],
+            'unknown group' => [['receive_block_groups' => ['8']], ['mail_policy_entry_invalid', 'group:8']],
+            'reject text with line break' => [['reject_text' => "a\r\nb"], 'mail_policy_reject_text_invalid'],
+            'reject text not ASCII' => [['reject_text' => 'Nur für Azubis'], 'mail_policy_reject_text_invalid'],
+            'mailbox of another domain' => [['mailboxes' => 'andere@tochter.de'], ['mail_policy_member_invalid', 'andere@tochter.de']],
+            'group of another domain' => [['groups' => ['9']], ['mail_policy_member_invalid', '9']],
+            'unknown domain' => [['domain' => 'fremd.de'], ['domain_not_found', 'fremd.de']],
+        ];
+    }
+
+    #[DataProvider('invalidInput')]
+    public function testInvalidInput(array $input, string|array $error): void
+    {
+        $this->expectUserError($error, fn() => $this->service()->create($input + ['domain' => 'firma.de', 'name' => 'Test']));
+        $this->assertSame([], $this->saved);
+    }
+
+    public function testNamesAreUniquePerDomain(): void
+    {
+        $this->repo->method('nameExists')->willReturn(true);
+        $this->expectUserError(['object_exists', 'Azubis'], fn() => $this->service()->create(['domain' => 'firma.de', 'name' => 'Azubis']));
+    }
+
+    public function testPermissions(): void
+    {
+        $this->repo->method('find')->willReturn($this->stored());
+        $da = FakeContext::domainAdmin([], ['firma.de'], ['mail_policies' => '1', 'mailbox_groups' => '1']);
+
+        $this->assertSame('Test', $this->service($da)->create(['domain' => 'firma.de', 'name' => 'Test'])->name);
+        $this->assertNotNull($this->service($da)->get(3));
+        // other domains, no ACL, users and read-only keys
+        $this->expectUserError('access_denied', fn() => $this->service($da)->create(['domain' => 'tochter.de', 'name' => 'Test']));
+        $this->expectUserError(['mail_policy_entry_invalid', 'group:9'],
+            fn() => $this->service($da)->create(['domain' => 'firma.de', 'name' => 'Test', 'send_block_groups' => ['9']]));
+        $this->assertNull($this->service(FakeContext::domainAdmin([], ['tochter.de'], ['mail_policies' => '1']))->get(3));
+        $this->expectUserError('access_denied', fn() => $this->service(FakeContext::domainAdmin([], ['firma.de'], []))->create(['domain' => 'firma.de', 'name' => 'Test']));
+        $this->expectUserError('access_denied', fn() => $this->service(FakeContext::user('azubi@firma.de'))->update(3, []));
+        $readOnly = new Context('admin', 'API', [], false, 'ro');
+        $this->assertNotNull($this->service($readOnly)->get(3));
+        $this->expectUserError('access_denied', fn() => $this->service($readOnly)->delete(3));
+    }
+
+    public function testGroupsNeedTheGroupAcl(): void
+    {
+        $this->repo->method('find')->willReturn($this->stored(['groups' => [7]]));
+        $da = FakeContext::domainAdmin([], ['firma.de'], ['mail_policies' => '1']);
+
+        $this->assertSame([], $this->service($da)->groupChoices(['firma.de']));
+        // the form sends empty group fields: the group entries and assignments stay
+        $policy = $this->service($da)->update(3, ['send_allow' => 'kunde.example', 'send_allow_groups' => '', 'groups' => '']);
+        $this->assertSame([['kunde.example', 'group:7'], [7]], [$policy->sendAllow, $policy->groups]);
+        // the stored values sent back unchanged, as returned by the API
+        $policy = $this->service($da)->update(3, ['send_allow' => ['partner.de', 'group:7'], 'groups' => ['7']]);
+        $this->assertSame([['partner.de', 'group:7'], [7]], [$policy->sendAllow, $policy->groups]);
+        $this->expectUserError('access_denied', fn() => $this->service($da)->update(3, ['groups' => ['7', '8']]));
+        $this->expectUserError('access_denied', fn() => $this->service($da)->create(['domain' => 'firma.de', 'name' => 'Test', 'groups' => ['7']]));
+        $this->expectUserError(['mail_policy_entry_invalid', 'group:7'],
+            fn() => $this->service($da)->create(['domain' => 'firma.de', 'name' => 'Test', 'send_block' => 'group:7']));
+        $this->assertCount(1, $this->service(FakeContext::domainAdmin([], ['firma.de'], ['mail_policies' => '1', 'mailbox_groups' => '1']))->groupChoices(['firma.de']));
+    }
+
+    public function testGroupEntriesBelongToThePolicyDomain(): void
+    {
+        // also for admins: the policy of firma.de cannot name a group of tochter.de
+        $this->expectUserError(['mail_policy_entry_invalid', 'group:9'],
+            fn() => $this->service()->create(['domain' => 'firma.de', 'name' => 'Test', 'receive_block' => 'group:9']));
+    }
+
+    public function testListsAreLimitedBeforeAnythingIsLookedUp(): void
+    {
+        $groups = array_map(fn(int $i): string => 'group:' . $i, range(1, 501));
+        $this->expectUserError(['mail_policy_entries_exceeded', 500], fn() => $this->service()->create(['domain' => 'firma.de', 'name' => 'Test', 'send_block' => $groups]));
+        $this->assertSame(0, $this->groupLookups);
+        // repeats count once
+        $this->assertSame(['group:7'], $this->service()->create(['domain' => 'firma.de', 'name' => 'Test', 'send_block' => array_fill(0, 600, 'group:7')])->sendBlock);
+        $this->expectUserError(['mail_policy_entries_exceeded', 500],
+            fn() => $this->service()->create(['domain' => 'firma.de', 'name' => 'Test', 'mailboxes' => array_map(fn(int $i): string => "m$i@firma.de", range(1, 501))]));
+    }
+
+    public function testRuleTestShowsNothingOfOtherDomains(): void
+    {
+        $this->lookup->mailboxes['andere@tochter.de'] = 'tochter.de';
+        $this->lookup->mailboxPolicies['andere@tochter.de'] = [$this->stored(['id' => 5, 'domain' => 'tochter.de', 'name' => 'Geheim',
+            'sendAllow' => [], 'receiveMode' => 'internal', 'rejectText' => 'Interner Text'])];
+        $this->repo->method('mailboxDomain')->willReturnCallback(fn(string $username): ?string => $this->lookup->mailboxes[$username] ?? null);
+        $da = FakeContext::domainAdmin([], ['firma.de'], ['mail_policies' => '1']);
+
+        // a policy of another domain: neither name nor text
+        $this->assertSame(['allowed' => 0, 'side' => 'receive', 'policy' => null, 'internal_alias' => 0, 'logged_in' => 1,
+            'text' => 'This recipient does not accept mail from this sender'], $this->service($da)->test('azubi@firma.de', 'andere@tochter.de', true));
+        // a sender of another domain is not tested as logged in, so its mailbox and its rules stay hidden
+        $this->assertSame(0, $this->service($da)->test('andere@tochter.de', 'chef@firma.de', true)['logged_in']);
+    }
+
+    public function testRuleTest(): void
+    {
+        $policy = $this->stored(['sendMode' => 'internal', 'sendAllow' => []]);
+        $this->lookup->mailboxPolicies['azubi@firma.de'] = [$policy];
+
+        $this->assertSame(['allowed' => 0, 'side' => 'send', 'policy' => 'Azubis', 'internal_alias' => 0, 'logged_in' => 1,
+            'text' => 'Sending to this recipient is not allowed by the mail policy of the sender'],
+            $this->service()->test('azubi@firma.de', 'x@extern.example', true));
+        // not logged in: the send rules of the mailbox do not apply
+        $this->assertSame(1, $this->service()->test('azubi@firma.de', 'x@extern.example', false)['allowed']);
+        // an external sender is never logged in
+        $this->assertSame(0, $this->service()->test('x@extern.example', 'chef@firma.de', true)['logged_in']);
+        $this->expectUserError('mail_policy_test_invalid', fn() => $this->service()->test('azubi@firma.de', 'kein-empfaenger', true));
+        // domain admins test mail of their domains
+        $da = FakeContext::domainAdmin([], ['tochter.de'], ['mail_policies' => '1']);
+        $this->expectUserError('access_denied', fn() => $this->service($da)->test('azubi@firma.de', 'x@extern.example', true));
+    }
+}

tests/php/Support/FakeMailPolicyLookup.php

@@ -0,0 +1,123 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Mailcow\Tests\Support;
+
+use Mailcow\MailPolicy\Model\Policy;
+use Mailcow\MailPolicy\Repository\LookupRepository;
+
+/**
+ * Address tables and policy assignments in memory, with the conditions of the SQL already applied
+ * (only active rows are listed).
+ */
+class FakeMailPolicyLookup extends LookupRepository
+{
+    /** username => domain */
+    public array $mailboxes = [];
+    /** alias domain => target domain */
+    public array $aliasDomains = [];
+    /** @var string[] domains of the mailcow (without alias domains) */
+    public array $domains = [];
+    /** id => ['address' => ?string, 'members' => string[]] */
+    public array $groups = [];
+    /** alias address => ['domain' => string, 'internal' => bool] (active aliases, also own aliases of mailboxes) */
+    public array $aliases = [];
+    /** temporary alias => owner mailbox */
+    public array $temporaryAliases = [];
+    /** @var string[] domains with an internal catch-all alias */
+    public array $internalCatchAlls = [];
+    /** an active policy restricts sending */
+    public bool $sendRules = false;
+    /** other spelling (MySQL ignores accents) => stored address or domain */
+    public array $spellings = [];
+    /** username => Policy[] assigned directly */
+    public array $mailboxPolicies = [];
+    /** group id => Policy[] */
+    public array $groupPolicies = [];
+
+    public function __construct()
+    {
+    }
+
+    public function mailbox(string $username): ?array
+    {
+        return isset($this->mailboxes[$username]) ? ['username' => $username, 'domain' => $this->mailboxes[$username]] : null;
+    }
+
+    public function aliasDomainTarget(string $domain): ?string
+    {
+        return $this->aliasDomains[$domain] ?? null;
+    }
+
+    public function isLocalDomain(string $domain): bool
+    {
+        return in_array($domain, $this->domains, true) || isset($this->aliasDomains[$domain]);
+    }
+
+    public function groupByAddress(string $address): ?int
+    {
+        foreach ($this->groups as $id => $group) {
+            if (($group['address'] ?? null) === $address) {
+                return $id;
+            }
+        }
+        return null;
+    }
+
+    public function groupAddress(int $id): ?string
+    {
+        return $this->groups[$id]['address'] ?? null;
+    }
+
+    public function isGroupMember(int $groupId, string $username): bool
+    {
+        return in_array($username, $this->groups[$groupId]['members'] ?? [], true);
+    }
+
+    public function aliasTarget(string $address): ?array
+    {
+        if (isset($this->aliases[$address])) {
+            return ['kind' => 'alias', 'domain' => $this->aliases[$address]['domain'], 'internal' => $this->aliases[$address]['internal']];
+        }
+        return isset($this->temporaryAliases[$address]) ? ['kind' => 'temporary', 'owner' => $this->temporaryAliases[$address]] : null;
+    }
+
+    public function internalCatchAll(string $domain): bool
+    {
+        return in_array($domain, $this->internalCatchAlls, true);
+    }
+
+    public function hasSendRules(): bool
+    {
+        return $this->sendRules;
+    }
+
+    public function storedAddress(string $address): ?string
+    {
+        $address = $this->spellings[$address] ?? $address;
+        return (isset($this->mailboxes[$address]) || isset($this->aliases[$address]) || isset($this->temporaryAliases[$address])) ? $address : null;
+    }
+
+    public function storedDomain(string $domain): ?string
+    {
+        $domain = $this->spellings[$domain] ?? $domain;
+        return (in_array($domain, $this->domains, true) || isset($this->aliasDomains[$domain])) ? $domain : null;
+    }
+
+    public function policiesForMailbox(string $username): array
+    {
+        $policies = $this->mailboxPolicies[$username] ?? [];
+        foreach ($this->groups as $id => $group) {
+            if (in_array($username, $group['members'] ?? [], true)) {
+                $policies = array_merge($policies, $this->groupPolicies[$id] ?? []);
+            }
+        }
+        return $policies;
+    }
+
+    public function policiesForGroup(int $groupId): array
+    {
+        return $this->groupPolicies[$groupId] ?? [];
+    }
+}