fix: only allow ports above 1024 for imap + smtp

Default behavior is processing headers
that are actually part of the message body.
This is unlikely to be needed
as headers such as Received are not added into MIME parts,
but may result in broken DKIM signatures
if the body is modified.

.github/workflows/ci-no-dns.yaml

@@ -20,9 +20,9 @@ concurrency:
 jobs:
   no-dns:
     name: LXC deploy and test
-    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@v0.14.6
+    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@main
     with:
-      cmlxc_version: v0.14.6
+      cmlxc_version: main
       cmlxc_commands: |
         cmlxc init 
         # single cmdeploy relay test

.github/workflows/ci.yaml

@@ -29,7 +29,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
           persist-credentials: false
       - name: download filtermail
-        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.6.6/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
+        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.7.4/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
       - name: run chatmaild tests 
         working-directory: chatmaild
         run: pipx run tox
@@ -57,9 +57,9 @@ jobs:
 
   lxc-test:
     name: LXC deploy and test
-    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@v0.14.6
+    uses: chatmail/cmlxc/.github/workflows/lxc-test.yml@main
     with:
-      cmlxc_version: v0.14.6
+      cmlxc_version: main
       cmlxc_commands: |
         cmlxc init 
         # single cmdeploy relay test

README.md

@@ -8,7 +8,12 @@ Chatmail relay servers are interoperable Mail Transport Agents (MTAs) designed f
 -  **Instant/Realtime:** sub-second message delivery, realtime P2P
    streaming, privacy-preserving Push Notifications for Apple, Google, and Huawei;
 
--  **Security Enforcement**: only strict TLS, DKIM and OpenPGP with minimized metadata accepted
+-  **Security Enforcement**: Only connections with strict TLS are accepted;
+   all messages must be correctly signed with DKIM and OpenPGP-encrypted with minimized metadata.
+   There are experimental exceptions for no-DNS relays,
+   which are allowed use self-signed TLS certificates
+   and which do not need to DKIM-sign their messages.
+   Unencrypted messages are allowed in neither case.
 
 -  **Reliable Federation and Decentralization:** No spam or IP reputation checks, federating
    depends on established IETF standards and protocols.

chatmaild/pyproject.toml

@@ -9,8 +9,7 @@ dependencies = [
   "iniconfig",
   "filelock",
   "requests",
-  "crypt-r >= 3.13.1 ; python_version >= '3.11'",
-  "domain-validator",
+  "crypt-r >= 3.13.1 ; python_version >= '3.13'",
 ]
 
 [tool.setuptools]

chatmaild/src/chatmaild/config.py

@@ -1,8 +1,8 @@
 import ipaddress
 from pathlib import Path
+from random import randint
 
 import iniconfig
-from domain_validator import DomainValidator
 
 from chatmaild.user import User
 
@@ -25,7 +25,6 @@ class Config:
             self.mail_domain = f"[{raw_domain}]"
             self.postfix_myhostname = ipaddress.IPv4Address(raw_domain).reverse_pointer
         else:
-            DomainValidator().validate_domain_re(raw_domain)
             self.ipv4_relay = None
             self.mail_domain = raw_domain
             self.postfix_myhostname = raw_domain
@@ -43,6 +42,11 @@ class Config:
         self.username_max_length = int(params.pop("username_max_length", 9))
         self.password_min_length = int(params.pop("password_min_length", 9))
         self.www_folder = params.pop("www_folder", "")
+
+        self.imap_port = int(params.pop("imap_port", 143))
+        self.imaps_port = int(params.pop("imaps_port", 993))
+        self.smtp_port = int(params.pop("smtp_port", 587))
+        self.smtps_port = int(params.pop("smtps_port", 465))
         self.filtermail_smtp_port = int(params.pop("filtermail_smtp_port", "10080"))
         self.filtermail_smtp_port_incoming = int(
             params.pop("filtermail_smtp_port_incoming", "10081")
@@ -140,8 +144,15 @@ def parse_size_mb(limit):
 
 def write_initial_config(inipath, mail_domain, overrides):
     """Write out default config file, using the specified config value overrides."""
-    content = get_default_config_content(mail_domain, **overrides)
-    inipath.write_text(content)
+    content = get_default_config_content(mail_domain, **overrides).splitlines()
+    used_ports = [25, 53, 80, 143, 402, 443, 465, 587, 993, 3340, 3903, 3904, 8443, 10080, 10081, 10082, 10083, 10025, 10026]
+    for config_key in ["smtp_port", "imap_port", "smtps_port", "imaps_port"]:
+        value = randint(1024, 65536)
+        while value in used_ports:
+            value = randint(65535)
+        used_ports.append(value)
+        content.append(f"{config_key} = {value}")
+    inipath.write_text("\n".join(content))
 
 
 def get_default_config_content(mail_domain, **overrides):

chatmaild/src/chatmaild/expire.py

@@ -168,6 +168,16 @@ class Expiry:
         if mbox.last_login and mbox.last_login < cutoff_without_login:
             self.remove_mailbox(mbox.basedir)
             return
+        elif mbox.last_login is None:
+            try:
+                if not self.dry:
+                    os.rmdir(mbox.basedir)
+                    self.del_mboxes += 1
+            except OSError:
+                print_info(
+                    f"Skipped deleting {mbox.basedir}, doesn't have last_login but isn't empty"
+                )
+            return
 
         mboxname = os.path.basename(mbox.basedir)
         if self.verbose:

chatmaild/src/chatmaild/tests/test_expire.py

@@ -1,6 +1,7 @@
 import itertools
 import os
 import random
+import shutil
 import time
 from datetime import datetime
 from fnmatch import fnmatch
@@ -9,6 +10,7 @@ from pathlib import Path
 import pytest
 
 from chatmaild.expire import (
+    Expiry,
     FileEntry,
     MailboxStat,
     expire_to_target,
@@ -104,6 +106,32 @@ def test_stats_mailbox(mbox1):
     assert mbox3.last_login is None
 
 
+def test_mbox_without_password(mbox1, example_config, capsys):
+    password = Path(mbox1.basedir).joinpath("password")
+    os.remove(password)
+    mbox_rescan = MailboxStat(mbox1.basedir)
+    assert mbox_rescan.last_login is None
+
+    exp = Expiry(
+        example_config, dry=False, now=datetime.now().timestamp(), verbose=False
+    )
+    exp.process_mailbox_stat(mbox_rescan)
+    out, err = capsys.readouterr()
+    assert "doesn't have last_login but isn't empty" in err
+    assert os.path.isdir(mbox_rescan.basedir)
+
+    for entry in os.scandir(mbox_rescan.basedir):
+        if os.path.isdir(entry):
+            shutil.rmtree(entry)
+        else:
+            os.remove(entry)
+
+    exp.process_mailbox_stat(mbox_rescan)
+    out, err = capsys.readouterr()
+    assert "doesn't have last_login but isn't empty" not in err
+    assert not os.path.isdir(mbox_rescan.basedir)
+
+
 def test_report_no_mailboxes(example_config):
     args = (str(example_config._inipath),)
     report_main(args)

cmdeploy/pyproject.toml

@@ -19,8 +19,8 @@ dependencies = [
   "pytest-xdist", 
   "execnet",
   "imap_tools",
-  "deltachat-rpc-client==2.49.0",
-  "deltachat-rpc-server==2.49.0",
+  "deltachat-rpc-client",
+  "deltachat-rpc-server",
 ]
 
 [project.scripts]

cmdeploy/src/cmdeploy/acmetool/response-file.yaml.j2

@@ -1,2 +1,2 @@
 "acme-enter-email": "{{ email }}"
-"acme-agreement:https://letsencrypt.org/documents/LE-SA-v1.6-August-18-2025.pdf": true
+"acme-agreement:https://letsencrypt.org/documents/LE-SA-v1.8-July-06-2026.pdf": true

cmdeploy/src/cmdeploy/basedeploy.py

@@ -166,7 +166,7 @@ class Deployer:
             return self.put_template(src, dest, **kwargs)
         return self.put_file(src, dest)
 
-    def put_file(self, src, dest, mode="644"):
+    def put_file(self, src, dest, mode="644", **kwargs):
         if isinstance(src, str):
             src = get_resource(src)
         res = files.put(
@@ -176,6 +176,7 @@ class Deployer:
             user="root",
             group="root",
             mode=mode,
+            **kwargs,
         )
 
         return self._update_restart_signals(dest, res)

cmdeploy/src/cmdeploy/deployers.py

@@ -164,6 +164,7 @@ class UnboundDeployer(Deployer):
         self.put_file(
             src=BytesIO(b"nameserver 127.0.0.1\nnameserver 9.9.9.9\n"),
             dest="/etc/resolv.conf",
+            force=True,
         )
         server.shell(
             name="Generate root keys for validating DNSSEC",
@@ -171,16 +172,14 @@ class UnboundDeployer(Deployer):
                 "unbound-anchor -a /var/lib/unbound/root.key || true",
             ],
         )
-        if self.config.disable_ipv6:
-            self.ensure_directory(
-                path="/etc/unbound/unbound.conf.d",
-            )
-            self.put_template(
-                "unbound/unbound.conf.j2",
-                "/etc/unbound/unbound.conf.d/chatmail.conf",
-            )
-        else:
-            self.remove_file("/etc/unbound/unbound.conf.d/chatmail.conf")
+        self.ensure_directory(
+            path="/etc/unbound/unbound.conf.d",
+        )
+        self.put_template(
+            "unbound/unbound.conf.j2",
+            "/etc/unbound/unbound.conf.d/chatmail.conf",
+            disable_ipv6=self.config.disable_ipv6,
+        )
 
     def activate(self):
         server.shell(
@@ -497,15 +496,15 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
         if config.tls_cert_mode == "acme":
             port_services.append(("acmetool", 402))
         port_services += [
-            (["imap-login", "dovecot"], 143),
+            (["imap-login", "dovecot", "nginx"], config.imap_port),
             # acmetool previously listened on port 80,
             # so don't complain during upgrade that moved it to port 402
             # and gave the port to nginx.
             (["acmetool", "nginx"], 80),
             ("nginx", 443),
-            (["master", "smtpd"], 465),
-            (["master", "smtpd"], 587),
-            (["imap-login", "dovecot"], 993),
+            (["master", "smtpd", "nginx"], config.smtp_port),
+            (["master", "smtpd", "nginx"], config.smtps_port),
+            (["imap-login", "dovecot", "nginx"], config.imaps_port),
             ("iroh-relay", 3340),
             ("mtail", 3903),
             ("stats", 3904),
@@ -514,6 +513,8 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
             (["master", "smtpd"], config.postfix_reinject_port_incoming),
             ("filtermail", config.filtermail_smtp_port),
             ("filtermail", config.filtermail_smtp_port_incoming),
+            ("filtermail", config.filtermail_http_port_incoming),
+            ("filtermail", config.filtermail_lmtp_port_transport),
         ]
         for service, port in port_services:
             print(f"Checking if port {port} is available for {service}...")

cmdeploy/src/cmdeploy/filtermail/deployer.py

@@ -20,10 +20,10 @@ class FiltermailDeployer(Deployer):
             return
 
         arch = host.get_fact(facts.server.Arch)
-        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.6/filtermail-{arch}"
+        url = f"https://github.com/chatmail/filtermail/releases/download/v0.7.4/filtermail-{arch}"
         sha256sum = {
-            "x86_64": "05c7e7ac244606c2eeb275f2d282ffdbc2403e0169f1cdd3110ffcebdb994a92",
-            "aarch64": "8cf8bbda4d907beca547b365cc7e6753532a74b1712492d0d2f3d2d8a553fb3d",
+            "x86_64": "484cb8dff083134aefba9fce4a6b7ef4784a0f0e28e5108ecf8bb9e58a44fd2c",
+            "aarch64": "66aa0ca2ca9add7a12d92883d76f8786384092adfde24a3d3a1d0b1f30d23a9e",
         }[arch]
         self.download_executable(url, self.bin_path, sha256sum)
 

cmdeploy/src/cmdeploy/mtail/delivered_mail.mtail

@@ -73,6 +73,11 @@ counter incoming_unencrypted_mail_count
   filtered_incoming_mail_count++
 }
 
+counter incoming_mailer_daemon_mail_count
+/Incoming: Filtering mailer-daemon message from/ {
+  incoming_mailer_daemon_mail_count++
+  filtered_incoming_mail_count++
+}
 
 counter rejected_unencrypted_mail_count
 /Rejected unencrypted mail/ {

cmdeploy/src/cmdeploy/nginx/autoconfig.xml.j2

@@ -7,14 +7,14 @@
     <displayShortName>{{ config.mail_domain }}</displayShortName>
     <incomingServer type="imap">
       <hostname>{{ config.mail_domain }}</hostname>
-      <port>993</port>
+      <port>{{ config.imaps_port }}</port>
       <socketType>SSL</socketType>
       <authentication>password-cleartext</authentication>
       <username>%EMAILADDRESS%</username>
     </incomingServer>
     <incomingServer type="imap">
       <hostname>{{ config.mail_domain }}</hostname>
-      <port>143</port>
+      <port>{{ config.imap_port }}</port>
       <socketType>STARTTLS</socketType>
       <authentication>password-cleartext</authentication>
       <username>%EMAILADDRESS%</username>
@@ -28,14 +28,14 @@
     </incomingServer>
     <outgoingServer type="smtp">
       <hostname>{{ config.mail_domain }}</hostname>
-      <port>465</port>
+      <port>{{ config.smtps_port }}</port>
       <socketType>SSL</socketType>
       <authentication>password-cleartext</authentication>
       <username>%EMAILADDRESS%</username>
     </outgoingServer>
     <outgoingServer type="smtp">
       <hostname>{{ config.mail_domain }}</hostname>
-      <port>587</port>
+      <port>{{ config.smtp_port }}</port>
       <socketType>STARTTLS</socketType>
       <authentication>password-cleartext</authentication>
       <username>%EMAILADDRESS%</username>

cmdeploy/src/cmdeploy/nginx/nginx.conf.j2

@@ -31,6 +31,26 @@ stream {
             ~\bimap\b 127.0.0.1:993;
         }
 
+        server {
+                listen {{ config.smtp_port }};
+                proxy_pass 127.0.0.1:587;
+        }
+
+        server {
+                listen {{ config.imap_port }};
+                proxy_pass 127.0.0.1:143;
+        }
+
+        server {
+                listen {{ config.smtps_port }};
+                proxy_pass 127.0.0.1:465;
+        }
+
+        server {
+                listen {{ config.imaps_port }};
+                proxy_pass 127.0.0.1:993;
+        }
+
         server {
                 listen 443;
                 {% if not disable_ipv6 %}

cmdeploy/src/cmdeploy/postfix/main.cf.j2

@@ -85,6 +85,14 @@ inet_protocols = all
 
 lmtp_header_checks = regexp:/etc/postfix/lmtp_header_cleanup
 
+# Do not apply header checks to MIME headers
+# and other headers that are actually part of the message body.
+# Reference:
+# <https://www.postfix.org/postconf.5.html#disable_mime_input_processing>
+# <https://www.postfix.org/header_checks.5.html>
+# <https://stump.io/blog/2020/11/29/a-little-gotcha-with-postfixs-header_checks/>
+disable_mime_input_processing = yes
+
 mua_client_restrictions = permit_sasl_authenticated, reject
 mua_sender_restrictions = reject_sender_login_mismatch, permit_sasl_authenticated, reject
 mua_helo_restrictions = permit_mynetworks, reject_invalid_helo_hostname, reject_non_fqdn_helo_hostname, permit

cmdeploy/src/cmdeploy/tests/plugin.py

@@ -10,13 +10,11 @@ from pathlib import Path
 
 import pytest
 from chatmaild.config import is_valid_ipv4, read_config
-from domain_validator import DomainValidator
 
 
 def format_mail_domain(raw_domain: str) -> str:
     if is_valid_ipv4(raw_domain):
         return f"[{raw_domain}]"
-    DomainValidator().validate_domain_re(raw_domain)
     return raw_domain
 
 
@@ -349,9 +347,9 @@ class ChatmailACFactory:
                 qr = (
                     f"dclogin:{addr}"
                     f"?p={password}&v=1"
-                    f"&ih={domain}&ip=993"
-                    f"&sh={domain}&sp=465"
-                    f"&ic=3&ss=default"
+                    f"&ih={domain}&ip=993&is=ssl"
+                    f"&sh={domain}&sp=465&ss=ssl"
+                    f"&ic=3"
                 )
                 future = account.add_transport_from_qr.future(qr)
             else:
@@ -362,7 +360,7 @@ class ChatmailACFactory:
 
             # ensure messages stay in INBOX so that they can be
             # concurrently fetched via extra IMAP connections during tests
-            account.set_config("delete_server_after", "10")
+            account.set_config("bcc_self", "1")
             accounts.append(account)
 
         for future in futures:

cmdeploy/src/cmdeploy/unbound/unbound.conf.j2

@@ -1,4 +1,7 @@
-# Managed by cmdeploy: disable IPv6 in unbound.
+# Managed by cmdeploy
 server:
+{% if disable_ipv6 %}
   interface: 127.0.0.1
   do-ip6: no
+{% endif %}
+  cache-max-negative-ttl: 0

doc/source/overview.rst

@@ -156,6 +156,7 @@ Chatmail relay dependency diagram
         postfix --- |10083|filtermail-transport;
         filtermail-outgoing --- |10025 reinject|postfix;
         filtermail-incoming --- |10026 reinject|postfix;
+        postfix --- |milter opendkim.sock|OpenDKIM
         dovecot --- |doveauth.socket|doveauth;
         dovecot --- |message delivery|maildir["maildir
         /home/vmail/.../user"];
@@ -179,26 +180,51 @@ Chatmail relay dependency diagram
         style nginx-right fill:#f66;
         style postfix fill:#f66;
         style dovecot fill:#f66;
+        style OpenDKIM fill:#f66;
         style notification-proxy fill:#f66;
 
-Message between users on the same relay
----------------------------------------
+Accepting and delivering mail
+-----------------------------
 
 .. mermaid::
-    :caption: This diagram shows the path a non-federated message takes.
+    :caption: This diagram shows all the paths a message can take.
 
-    graph LR;
-        sender --> |465|smtps/smtpd;
-        sender --> |587|submission/smtpd;
-        smtps/smtpd --> |10080|filtermail;
-        submission/smtpd --> |10080|filtermail;
-        filtermail --> |10025|smtpd_reinject;
-        smtpd_reinject --> cleanup;
-        cleanup --> qmgr;
-        qmgr --> smtpd_accepts_message;
-        qmgr --> |lmtp|dovecot;
-        dovecot --> recipient;
-        dovecot --> sender's_other_devices;
+    flowchart LR
+        subgraph chatmail relay
+            subgraph postfix
+                qmgr .-> lmtp-filtermail["lmtp/lmtp-filtermail (default_transport)"]
+                qmgr .-> lmtp["lmtp (local_transport)"]
+                lmtp --> cleanup["cleanup (lmtp_header_cleanup)"]
+                bounce
+                smtpd-submission["smtpd/submission"]
+                smtpd-smtps["smtpd/smtps"]
+                smtpd-reinject-outgoing["smtpd/reinject-outgoing"] --> authclean["cleanup/authclean (submission_header_cleanup)"]
+                authclean --> qmgr
+                smtpd-smtp["smtpd/smtp"]
+                smtpd-reinject-incoming["smtpd/reinject-incoming"] --> qmgr
+            end
+            lmtp-filtermail --LMTP inet:10083--> filtermail-transport
+            cleanup --LMTP unix:private/dovecot-lmtp --> dovecot
+            dovecot --> maildir
+            smtpd-submission --SMTP inet:10080--> filtermail-outgoing
+            smtpd-smtps --SMTP inet:10080--> filtermail-outgoing
+            filtermail-outgoing --SMTP inet:10025--> smtpd-reinject-outgoing
+            open-dkim["OpenDKIM (signing only)"] <--milter unix:opendkim/opendkim.sock--> smtpd-reinject-outgoing
+            bounce <--milter unix:opendkim/opendkim.sock--> open-dkim
+            bounce --> qmgr
+            nginx
+            smtpd-smtp -.SMTP inet:10081.-> filtermail-incoming
+            nginx -.HTTP inet:10082.-> filtermail-incoming
+            filtermail-incoming --SMTP inet:10026--> smtpd-reinject-incoming
+        end
+        filtermail-transport -.SMTP inet:25.-> mta1[Remote relay]
+        filtermail-transport -.HTTPS /mxdeliv.-> mta1
+        client[Client] -.SMTP inet:587.-> smtpd-submission
+        client -.SMTP inet:465.-> smtpd-smtps
+        client -.SMTP inet:443.-> nginx
+        nginx -.SMTP inet:465.-> smtpd-smtps
+        mta2[Remote relay] -.SMTP inet:25.-> smtpd-smtp
+        mta2 -.HTTPS /mxdeliv.-> nginx
 
 Operational details of a chatmail relay
 ----------------------------------------