Merge #2042

2042: Add MESSAGE_RATELIMIT_EXEMPTION r=mergify[bot] a=nextgens

## What type of PR?

Enhancement

## What does this PR do?

Add a new knob called ```MESSAGE_RATELIMIT_EXEMPTION```.

### Related issue(s)
- #1774

## Prerequisites
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [x] In case of feature or enhancement: documentation updated accordingly
- [ ] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Florent Daigniere <nextgens@freenetproject.org>

core/admin/mailu/configuration.py

@@ -54,6 +54,7 @@ DEFAULT_CONFIG = {
     'DKIM_PATH': '/dkim/{domain}.{selector}.key',
     'DEFAULT_QUOTA': 1000000000,
     'MESSAGE_RATELIMIT': '200/day',
+    'MESSAGE_RATELIMIT_EXEMPTION': '',
     'RECIPIENT_DELIMITER': '',
     # Web settings
     'SITENAME': 'Mailu',
@@ -156,6 +157,7 @@ class ConfigManager(dict):
         self.config['PERMANENT_SESSION_LIFETIME'] = timedelta(hours=int(self.config['SESSION_LIFETIME']))
         hostnames = [host.strip() for host in self.config['HOSTNAMES'].split(',')]
         self.config['AUTH_RATELIMIT_EXEMPTION'] = set(ipaddress.ip_network(cidr, False) for cidr in (cidr.strip() for cidr in self.config['AUTH_RATELIMIT_EXEMPTION'].split(',')) if cidr)
+        self.config['MESSAGE_RATELIMIT_EXEMPTION'] = set([s for s in self.config['MESSAGE_RATELIMIT_EXEMPTION'].lower().replace(' ', '').split(',') if s])
         self.config['HOSTNAMES'] = ','.join(hostnames)
         self.config['HOSTNAME'] = hostnames[0]
         # update the app config itself

core/admin/mailu/internal/views/postfix.py

@@ -149,6 +149,8 @@ def postfix_sender_login(sender):
 def postfix_sender_rate(sender):
     """ Rate limit outbound emails per sender login
     """
+    if sender in flask.current_app.config['MESSAGE_RATELIMIT_EXEMPTION']:
+        flask.abort(404)
     user = models.User.get(sender) or flask.abort(404)
     return flask.abort(404) if user.sender_limiter.hit() else flask.jsonify("450 4.2.1 You are sending too many emails too fast.")
 

docs/configuration.rst

@@ -69,9 +69,11 @@ The ``MESSAGE_SIZE_LIMIT`` is the maximum size of a single email. It should not
 be too low to avoid dropping legitimate emails and should not be too high to
 avoid filling the disks with large junk emails.
 
-The ``MESSAGE_RATELIMIT`` is the limit of messages a single user can send. This is
-meant to fight outbound spam in case of compromised or malicious account on the
-server.
+The ``MESSAGE_RATELIMIT`` (default: 200/day) is the maximum number of messages
+a single user can send. ``MESSAGE_RATELIMIT_EXEMPTION`` contains a comma delimited
+list of user email addresses that are exempted from any restriction.  Those
+settings are meant to reduce outbound spam in case of compromised or malicious
+account on the server.
 
 The ``RELAYNETS`` (default: unset) is a comma delimited list of network addresses
 for which mail is relayed for with no authentication required. This should be