feat: Sign bounce messages

Closes #873

Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>

.github/workflows/ci.yaml

@@ -15,7 +15,7 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.sha }}
       - name: download filtermail
-        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.6.0/filtermail-x86_64 -o /usr/local/bin/filtermail && chmod +x /usr/local/bin/filtermail
+        run: curl -L https://github.com/chatmail/filtermail/releases/download/v0.6.1/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

.github/workflows/test-and-deploy-ipv4only.yaml

@@ -84,6 +84,7 @@ jobs:
           ssh root@staging-ipv4.testrun.org "cd relay && scripts/cmdeploy init staging-ipv4.testrun.org"
           ssh root@staging-ipv4.testrun.org "sed -i 's#disable_ipv6 = False#disable_ipv6 = True#' relay/chatmail.ini"
           ssh root@staging-ipv4.testrun.org "sed -i 's/#\s*mtail_address/mtail_address/' relay/chatmail.ini"
+          ssh root@staging-ipv4.testrun.org "sed -i 's/max_mailbox_size = 500M/max_mailbox_size = 10k/' relay/chatmail.ini"
 
       - run: ssh root@staging-ipv4.testrun.org "cd relay && scripts/cmdeploy run --verbose --skip-dns-check --ssh-host localhost"
 

.github/workflows/test-and-deploy.yaml

@@ -76,7 +76,7 @@ jobs:
 
       - run: |
           cmdeploy init staging2.testrun.org
-          sed -i 's/#\s*mtail_address/mtail_address/' chatmail.ini
+          sed -i 's/#\s*mtail_address/mtail_address/;s/max_mailbox_size = 500M/max_mailbox_size = 10k/' chatmail.ini
 
       - run: cmdeploy run --verbose --skip-dns-check
 

chatmaild/pyproject.toml

@@ -6,10 +6,7 @@ build-backend = "setuptools.build_meta"
 name = "chatmaild"
 version = "0.3"
 dependencies = [
-  "aiosmtpd",
   "iniconfig",
-  "deltachat-rpc-server",
-  "deltachat-rpc-client",
   "filelock",
   "requests",
   "crypt-r >= 3.13.1 ; python_version >= '3.11'",
@@ -70,6 +67,7 @@ commands =
 deps = pytest 
        pdbpp 
        pytest-localserver
+       aiosmtpd
        execnet
 commands = pytest -v -rsXx {posargs}
 """

chatmaild/src/chatmaild/config.py

@@ -38,6 +38,7 @@ class Config:
         self.filtermail_smtp_port_incoming = int(
             params.get("filtermail_smtp_port_incoming", "10081")
         )
+        self.filtermail_http_port = int(params.get("filtermail_http_port", "10082"))
         self.postfix_reinject_port = int(params.get("postfix_reinject_port", "10025"))
         self.postfix_reinject_port_incoming = int(
             params.get("postfix_reinject_port_incoming", "10026")

cmdeploy/pyproject.toml

@@ -10,7 +10,6 @@ dependencies = [
   "pillow",
   "qrcode",
   "markdown",
-  "pytest",
   "setuptools>=68",
   "termcolor",
   "build",
@@ -21,6 +20,7 @@ dependencies = [
   "execnet",
   "imap_tools",
   "deltachat-rpc-client",
+  "deltachat-rpc-server",
 ]
 
 [project.scripts]

cmdeploy/src/cmdeploy/chatmail.zone.j2

@@ -1,32 +0,0 @@
-;
-; Required DNS entries for chatmail servers 
-;
-{% if A %}
-{{ mail_domain }}.                   A     {{ A }}
-{% endif %}
-{% if AAAA %}
-{{ mail_domain }}.                   AAAA  {{ AAAA }}
-{% endif %}
-{{ mail_domain }}.                   MX 10 {{ mail_domain }}.
-{% if strict_tls %}
-_mta-sts.{{ mail_domain }}.          TXT "v=STSv1; id={{ sts_id }}"
-mta-sts.{{ mail_domain }}.           CNAME {{ mail_domain }}.
-{% endif %}
-www.{{ mail_domain }}.               CNAME {{ mail_domain }}.
-{{ dkim_entry }}
-
-;
-; Recommended DNS entries for interoperability and security-hardening
-;
-{{ mail_domain }}.                   TXT "v=spf1 a ~all"
-_dmarc.{{ mail_domain }}.            TXT "v=DMARC1;p=reject;adkim=s;aspf=s"
-
-{% if acme_account_url %}
-{{ mail_domain }}.                   CAA 0 issue "letsencrypt.org;accounturi={{ acme_account_url }}"
-{% endif %}
-_adsp._domainkey.{{ mail_domain }}.  TXT "dkim=discardable"
-
-_submission._tcp.{{ mail_domain }}.  SRV 0 1 587 {{ mail_domain }}.
-_submissions._tcp.{{ mail_domain }}. SRV 0 1 465 {{ mail_domain }}.
-_imap._tcp.{{ mail_domain }}.        SRV 0 1 143 {{ mail_domain }}.
-_imaps._tcp.{{ mail_domain }}.       SRV 0 1 993 {{ mail_domain }}.

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -111,7 +111,6 @@ def run_cmd(args, out):
     if ssh_host in ["localhost", "@docker"]:
         if ssh_host == "@docker":
             env["CHATMAIL_NOPORTCHECK"] = "True"
-            env["CHATMAIL_NOSYSCTL"] = "True"
         cmd = f"{pyinf} @local {deploy_path} -y"
 
     if version.parse(pyinfra.__version__) < version.parse("3"):
@@ -210,6 +209,7 @@ def test_cmd(args, out):
     """Run local and online tests for chatmail deployment."""
 
     env = os.environ.copy()
+    env["CHATMAIL_INI"] = str(args.inipath.absolute())
     if args.ssh_host:
         env["CHATMAIL_SSH"] = args.ssh_host
 
@@ -376,14 +376,14 @@ def get_parser():
     return parser
 
 
-def get_sshexec(ssh_host: str, verbose=True):
+def get_sshexec(ssh_host: str, verbose=True, **kwargs):
     if ssh_host in ["localhost", "@local"]:
         return LocalExec(verbose, docker=False)
     elif ssh_host == "@docker":
         return LocalExec(verbose, docker=True)
     if verbose:
         print(f"[ssh] login to {ssh_host}")
-    return SSHExec(ssh_host, verbose=verbose)
+    return SSHExec(ssh_host, verbose=verbose, **kwargs)
 
 
 def main(args=None):

cmdeploy/src/cmdeploy/deployers.py

@@ -24,6 +24,7 @@ from .basedeploy import (
     Deployer,
     Deployment,
     activate_remote_units,
+    blocked_service_startup,
     configure_remote_units,
     get_resource,
     has_systemd,
@@ -149,33 +150,16 @@ class UnboundDeployer(Deployer):
         self.need_restart = False
 
     def install(self):
-        # Run local DNS resolver `unbound`.
+        # Run local DNS resolver `unbound`. `resolvconf` takes care of
-        # `resolvconf` takes care of setting up /etc/resolv.conf
+        # setting up /etc/resolv.conf to use 127.0.0.1 as the resolver.
-        # to use 127.0.0.1 as the resolver.
 
-        #
+        # On an IPv4-only system, if unbound is started but not configured,
-        # On an IPv4-only system, if unbound is started but not
+        # it causes subsequent steps to fail to resolve hosts.
-        # configured, it causes subsequent steps to fail to resolve hosts.
+        with blocked_service_startup():
-        # Here, we use policy-rc.d to prevent unbound from starting up
+            apt.packages(
-        # on initial install.  Later, we will configure it and start it.
+                name="Install unbound",
-        #
+                packages=["unbound", "unbound-anchor", "dnsutils"],
-        # For documentation about policy-rc.d, see:
+            )
-        # https://people.debian.org/~hmh/invokerc.d-policyrc.d-specification.txt
-        #
-        files.put(
-            src=get_resource("policy-rc.d"),
-            dest="/usr/sbin/policy-rc.d",
-            user="root",
-            group="root",
-            mode="755",
-        )
-
-        apt.packages(
-            name="Install unbound",
-            packages=["unbound", "unbound-anchor", "dnsutils"],
-        )
-
-        files.file("/usr/sbin/policy-rc.d", present=False)
 
     def configure(self):
         server.shell(
@@ -336,12 +320,12 @@ class TurnDeployer(Deployer):
     def install(self):
         (url, sha256sum) = {
             "x86_64": (
-                "https://github.com/chatmail/chatmail-turn/releases/download/v0.3/chatmail-turn-x86_64-linux",
+                "https://github.com/chatmail/chatmail-turn/releases/download/v0.4/chatmail-turn-x86_64-linux",
-                "841e527c15fdc2940b0469e206188ea8f0af48533be12ecb8098520f813d41e4",
+                "1ec1f5c50122165e858a5a91bcba9037a28aa8cb8b64b8db570aa457c6141a8a",
             ),
             "aarch64": (
-                "https://github.com/chatmail/chatmail-turn/releases/download/v0.3/chatmail-turn-aarch64-linux",
+                "https://github.com/chatmail/chatmail-turn/releases/download/v0.4/chatmail-turn-aarch64-linux",
-                "a5fc2d06d937b56a34e098d2cd72a82d3e89967518d159bf246dc69b65e81b42",
+                "0fb3e792419494e21ecad536464929dba706bb2c88884ed8f1788141d26fc756",
             ),
         }[host.get_fact(facts.server.Arch)]
 
@@ -474,8 +458,9 @@ class ChatmailDeployer(Deployer):
         ("iroh", None, None),
     ]
 
-    def __init__(self, mail_domain):
+    def __init__(self, config):
-        self.mail_domain = mail_domain
+        self.config = config
+        self.mail_domain = config.mail_domain
 
     def install(self):
         files.put(
@@ -498,12 +483,18 @@ class ChatmailDeployer(Deployer):
             name="Install rsync",
             packages=["rsync"],
         )
-        apt.packages(
-            name="Ensure cron is installed",
-            packages=["cron"],
-        )
 
     def configure(self):
+        # metadata crashes if the mailboxes dir does not exist
+        files.directory(
+            name="Ensure vmail mailbox directory exists",
+            path=str(self.config.mailboxes_dir),
+            user="vmail",
+            group="vmail",
+            mode="700",
+            present=True,
+        )
+
         # This file is used by auth proxy.
         # https://wiki.debian.org/EtcMailName
         server.shell(
@@ -633,7 +624,7 @@ def deploy_chatmail(config_path: Path, disable_mail: bool, website_only: bool) -
     tls_deployer = get_tls_deployer(config, mail_domain)
 
     all_deployers = [
-        ChatmailDeployer(mail_domain),
+        ChatmailDeployer(config),
         LegacyRemoveDeployer(),
         FiltermailDeployer(),
         JournaldDeployer(),

cmdeploy/src/cmdeploy/dns.py

@@ -1,11 +1,22 @@
 import datetime
-import importlib
-
-from jinja2 import Template
 
 from . import remote
 
 
+def parse_zone_records(text):
+    """Yield ``(name, ttl, rtype, rdata)`` from standard BIND-format text."""
+    for raw_line in text.splitlines():
+        line = raw_line.strip()
+        if not line or line.startswith(";"):
+            continue
+        try:
+            name, ttl, _in, rtype, rdata = line.split(None, 4)
+        except ValueError:
+            raise ValueError(f"Bad zone record line: {line!r}") from None
+        name = name.rstrip(".")
+        yield name, ttl, rtype.upper(), rdata
+
+
 def get_initial_remote_data(sshexec, mail_domain):
     return sshexec.logged(
         call=remote.rdns.perform_initial_checks, kwargs=dict(mail_domain=mail_domain)
@@ -31,13 +42,39 @@ def get_filled_zone_file(remote_data):
     if not sts_id:
         remote_data["sts_id"] = datetime.datetime.now().strftime("%Y%m%d%H%M")
 
-    template = importlib.resources.files(__package__).joinpath("chatmail.zone.j2")
+    d = remote_data["mail_domain"]
-    content = template.read_text()
+
-    zonefile = Template(content).render(**remote_data)
+    def append_record(name, rtype, rdata, ttl=3600):
-    lines = [x.strip() for x in zonefile.split("\n") if x.strip()]
+        lines.append(f"{name:<40} {ttl:<6} IN  {rtype:<5}  {rdata}")
+
+    lines = ["; Required DNS entries"]
+    if remote_data.get("A"):
+        append_record(f"{d}.", "A", remote_data["A"])
+    if remote_data.get("AAAA"):
+        append_record(f"{d}.", "AAAA", remote_data["AAAA"])
+    append_record(f"{d}.", "MX", f"10 {d}.")
+    if remote_data.get("strict_tls"):
+        append_record(f"_mta-sts.{d}.", "TXT", f'"v=STSv1; id={remote_data["sts_id"]}"')
+        append_record(f"mta-sts.{d}.", "CNAME", f"{d}.")
+    append_record(f"www.{d}.", "CNAME", f"{d}.")
+    lines.append(remote_data["dkim_entry"])
     lines.append("")
-    zonefile = "\n".join(lines)
+    lines.append("; Recommended DNS entries")
-    return zonefile
+    append_record(f"{d}.", "TXT", '"v=spf1 a ~all"')
+    append_record(f"_dmarc.{d}.", "TXT", '"v=DMARC1;p=reject;adkim=s;aspf=s"')
+    if remote_data.get("acme_account_url"):
+        append_record(
+            f"{d}.",
+            "CAA",
+            f'0 issue "letsencrypt.org;accounturi={remote_data["acme_account_url"]}"',
+        )
+    append_record(f"_adsp._domainkey.{d}.", "TXT", '"dkim=discardable"')
+    append_record(f"_submission._tcp.{d}.", "SRV", f"0 1 587 {d}.")
+    append_record(f"_submissions._tcp.{d}.", "SRV", f"0 1 465 {d}.")
+    append_record(f"_imap._tcp.{d}.", "SRV", f"0 1 143 {d}.")
+    append_record(f"_imaps._tcp.{d}.", "SRV", f"0 1 993 {d}.")
+    lines.append("")
+    return "\n".join(lines)
 
 
 def check_full_zone(sshexec, remote_data, out, zonefile) -> int:
@@ -58,7 +95,8 @@ def check_full_zone(sshexec, remote_data, out, zonefile) -> int:
         returncode = 1
     if remote_data.get("dkim_entry") in required_diff:
         out(
-            "If the DKIM entry above does not work with your DNS provider, you can try this one:\n"
+            "If the DKIM entry above does not work with your DNS provider,"
+            " you can try this one:\n"
         )
         out(remote_data.get("web_dkim_entry") + "\n")
     if recommended_diff:

cmdeploy/src/cmdeploy/dovecot/deployer.py

@@ -1,10 +1,10 @@
-import os
+import io
 import urllib.request
 
 from chatmaild.config import Config
 from pyinfra import host
 from pyinfra.facts.deb import DebPackages
-from pyinfra.facts.server import Arch, Sysctl
+from pyinfra.facts.server import Arch, Command, Sysctl
 from pyinfra.operations import apt, files, server, systemd
 
 from cmdeploy.basedeploy import (
@@ -38,9 +38,33 @@ class DovecotDeployer(Deployer):
     def install(self):
         arch = host.get_fact(Arch)
         with blocked_service_startup():
-            _install_dovecot_package("core", arch)
+            debs = []
-            _install_dovecot_package("imapd", arch)
+            for pkg in ("core", "imapd", "lmtpd"):
-            _install_dovecot_package("lmtpd", arch)
+                deb = _download_dovecot_package(pkg, arch)
+                if deb:
+                    debs.append(deb)
+            if debs:
+                deb_list = " ".join(debs)
+                server.shell(
+                    name="Install dovecot packages",
+                    commands=[
+                        f"dpkg --force-confdef --force-confold -i {deb_list} 2> /dev/null || true",
+                        "DEBIAN_FRONTEND=noninteractive apt-get -y --fix-broken install",
+                        f"dpkg --force-confdef --force-confold -i {deb_list}",
+                    ],
+                )
+        files.put(
+            name="Pin dovecot packages to block Debian dist-upgrades",
+            src=io.StringIO(
+                "Package: dovecot-*\n"
+                "Pin: version *\n"
+                "Pin-Priority: -1\n"
+            ),
+            dest="/etc/apt/preferences.d/pin-dovecot",
+            user="root",
+            group="root",
+            mode="644",
+        )
 
     def configure(self):
         configure_remote_units(self.config.mail_domain, self.units)
@@ -73,7 +97,8 @@ def _pick_url(primary, fallback):
         return fallback
 
 
-def _install_dovecot_package(package: str, arch: str):
+def _download_dovecot_package(package: str, arch: str):
+    """Download a dovecot .deb if needed, return its path (or None)."""
     arch = "amd64" if arch == "x86_64" else arch
     arch = "arm64" if arch == "aarch64" else arch
 
@@ -81,11 +106,11 @@ def _install_dovecot_package(package: str, arch: str):
     sha256 = DOVECOT_SHA256.get((package, arch))
     if sha256 is None:
         apt.packages(packages=[pkg_name])
-        return
+        return None
 
     installed_versions = host.get_fact(DebPackages).get(pkg_name, [])
     if DOVECOT_VERSION in installed_versions:
-        return
+        return None
 
     url_version = DOVECOT_VERSION.replace("+", "%2B")
     deb_base = f"{pkg_name}_{url_version}_{arch}.deb"
@@ -102,10 +127,21 @@ def _install_dovecot_package(package: str, arch: str):
         cache_time=60 * 60 * 24 * 365 * 10,  # never redownload the package
     )
 
-    apt.deb(name=f"Install {pkg_name}", src=deb_filename)
+    return deb_filename
 
 
-def _configure_dovecot(config: Config, debug: bool = False) -> (bool, bool):
+def _can_set_inotify_limits() -> bool:
+    is_container = (
+        host.get_fact(
+            Command,
+            "systemd-detect-virt --container --quiet 2>/dev/null && echo yes || true",
+        )
+        == "yes"
+    )
+    return not is_container
+
+
+def _configure_dovecot(config: Config, debug: bool = False) -> tuple[bool, bool]:
     """Configures Dovecot IMAP server."""
     need_restart = False
     daemon_reload = False
@@ -140,19 +176,25 @@ def _configure_dovecot(config: Config, debug: bool = False) -> (bool, bool):
 
     # as per https://doc.dovecot.org/2.3/configuration_manual/os/
     # it is recommended to set the following inotify limits
-    if not os.environ.get("CHATMAIL_NOSYSCTL"):
+    can_modify = _can_set_inotify_limits()
-        for name in ("max_user_instances", "max_user_watches"):
+    for name in ("max_user_instances", "max_user_watches"):
-            key = f"fs.inotify.{name}"
+        key = f"fs.inotify.{name}"
-            if host.get_fact(Sysctl)[key] > 65535:
+        value = host.get_fact(Sysctl)[key]
-                # Skip updating limits if already sufficient
+        if value > 65534:
-                # (enables running in incus containers where sysctl readonly)
+            continue
-                continue
+        if not can_modify:
-            server.sysctl(
+            print(
-                name=f"Change {key}",
+                "\n!!!! refusing to attempt sysctl setting in containers\n"
-                key=key,
+                f"!!!! dovecot: sysctl {key!r}={value}, should be >65534 for production setups\n"
-                value=65535,
+                "!!!!"
-                persist=True,
             )
+            continue
+        server.sysctl(
+            name=f"Change {key}",
+            key=key,
+            value=65535,
+            persist=True,
+        )
 
     timezone_env = files.line(
         name="Set TZ environment variable",

cmdeploy/src/cmdeploy/filtermail/deployer.py

@@ -14,10 +14,10 @@ class FiltermailDeployer(Deployer):
 
     def install(self):
         arch = host.get_fact(facts.server.Arch)
-        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.0/filtermail-{arch}"
+        url = f"https://github.com/chatmail/filtermail/releases/download/v0.6.1/filtermail-{arch}"
         sha256sum = {
-            "x86_64": "3fd8b18282252c75a5bbfa603d8c1b65f6563e5e920bddf3e64e451b7cdb43ce",
+            "x86_64": "48b3fb80c092d00b9b0a0ef77a8673496da3b9aed5ec1851e1df936d5589d62f",
-            "aarch64": "2bd191de205f7fd60158dd8e3516ab7e3efb14627696f3d7dc186bdcd9e10a43",
+            "aarch64": "c65bd5f45df187d3d65d6965a285583a3be0f44a6916ff12909ff9a8d702c22e",
         }[arch]
         self.need_restart |= files.download(
             name="Download filtermail",

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

@@ -73,6 +73,10 @@ http {
 
 		access_log syslog:server=unix:/dev/log,facility=local7;
 
+		location /mxdeliv/ {
+		    proxy_pass http://127.0.0.1:{{ config.filtermail_http_port }};
+		}
+
 		location / {
 			# First attempt to serve request as file, then
 			# as directory, then fall back to displaying a 404.

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

@@ -20,7 +20,7 @@ smtpd_tls_key_file={{ config.tls_key_path }}
 smtpd_tls_security_level=may
 
 smtp_tls_CApath=/etc/ssl/certs
-smtp_tls_security_level={{ "verify" if config.tls_cert_mode == "acme" else "encrypt" }}
+smtp_tls_security_level=verify
 # Send SNI extension when connecting to other servers.
 # <https://www.postfix.org/postconf.5.html#smtp_tls_servername>
 smtp_tls_servername = hostname
@@ -88,6 +88,22 @@ inet_protocols = ipv4
 inet_protocols = all
 {% endif %}
 
+# Postfix does not try IPv4 and IPv6 connections
+# concurrently as of version 3.7.11.
+#
+# When relay has both A (IPv4) and AAAA (IPv6) records,
+# but broken IPv6 connectivity,
+# every second message is delayed by the connection timeout
+# <https://www.postfix.org/postconf.5.html#smtp_connect_timeout>
+# which defaults to 30 seconds. Reducing timeouts is not a solution
+# as this will result in a failure to connect to slow servers.
+#
+# As a workaround we always prefer IPv4 when it is available.
+# 
+# The setting is documented at
+# <https://www.postfix.org/postconf.5.html#smtp_address_preference>
+smtp_address_preference=ipv4
+
 virtual_transport = lmtp:unix:private/dovecot-lmtp
 virtual_mailbox_domains = {{ config.mail_domain }}
 lmtp_header_checks = regexp:/etc/postfix/lmtp_header_cleanup

cmdeploy/src/cmdeploy/postfix/master.cf.j2

@@ -51,12 +51,15 @@ smtps     inet  n       -       y       -       5000    smtpd
   -o smtpd_proxy_filter=127.0.0.1:{{ config.filtermail_smtp_port }}
 #628       inet  n       -       y       -       -       qmqpd
 pickup    unix  n       -       y       60      1       pickup
+ -o cleanup_service_name=signlocal
 cleanup   unix  n       -       y       -       0       cleanup
 qmgr      unix  n       -       n       300     1       qmgr
 #qmgr     unix  n       -       n       300     1       oqmgr
 tlsmgr    unix  -       -       y       1000?   1       tlsmgr
 rewrite   unix  -       -       y       -       -       trivial-rewrite
 bounce    unix  -       -       y       -       0       bounce
+  -o internal_mail_filter_classes=bounce
+  -o cleanup_service_name=signlocal
 defer     unix  -       -       y       -       0       bounce
 trace     unix  -       -       y       -       0       bounce
 verify    unix  -       -       y       -       1       verify
@@ -100,3 +103,9 @@ filter    unix -        n       n       -       -       lmtp
 # cannot send unprotected Subject.
 authclean unix  n       -       -       -       0       cleanup
   -o header_checks=regexp:/etc/postfix/submission_header_cleanup
+
+# Signs locally generated bounce messages.
+# These can't be signed using smtpd as they are not non-smtpd.
+signlocal unix  n       -       -       -       0       cleanup
+  -o milter_macro_daemon_name=ORIGINATING
+  -o non_smtpd_milters=unix:opendkim/opendkim.sock

cmdeploy/src/cmdeploy/remote/rdns.py

@@ -57,9 +57,10 @@ def get_dkim_entry(mail_domain, pre_command, dkim_selector):
     dkim_value_raw = f"v=DKIM1;k=rsa;p={dkim_pubkey};s=email;t=s"
     dkim_value = '" "'.join(re.findall(".{1,255}", dkim_value_raw))
     web_dkim_value = "".join(re.findall(".{1,255}", dkim_value_raw))
+    name = f"{dkim_selector}._domainkey.{mail_domain}."
     return (
-        f'{dkim_selector}._domainkey.{mail_domain}. TXT "{dkim_value}"',
+        f'{name:<40} 3600   IN  TXT    "{dkim_value}"',
-        f'{dkim_selector}._domainkey.{mail_domain}. TXT "{web_dkim_value}"',
+        f'{name:<40} 3600   IN  TXT    "{web_dkim_value}"',
     )
 
 
@@ -94,7 +95,7 @@ def check_zonefile(zonefile, verbose=True):
         if not zf_line.strip() or zf_line.startswith(";"):
             continue
         print(f"dns-checking {zf_line!r}") if verbose else log_progress("")
-        zf_domain, zf_typ, zf_value = zf_line.split(maxsplit=2)
+        zf_domain, _ttl, _in, zf_typ, zf_value = zf_line.split(None, 4)
         zf_domain = zf_domain.rstrip(".")
         zf_value = zf_value.strip()
         query_value = query_dns(zf_typ, zf_domain)

cmdeploy/src/cmdeploy/selfsigned/deployer.py

@@ -18,6 +18,8 @@ def openssl_selfsigned_args(domain, cert_path, key_path, days=36500):
         "-keyout", str(key_path),
         "-out", str(cert_path),
         "-subj", f"/CN={domain}",
+        # Mark as end-entity cert so it cannot be used as a CA to sign others.
+        "-addext", "basicConstraints=critical,CA:FALSE",
         "-addext", "extendedKeyUsage=serverAuth,clientAuth",
         "-addext",
         f"subjectAltName=DNS:{domain},DNS:www.{domain},DNS:mta-sts.{domain}",

cmdeploy/src/cmdeploy/sshexec.py

@@ -49,8 +49,9 @@ class SSHExec:
     RemoteError = execnet.RemoteError
     FuncError = FuncError
 
-    def __init__(self, host, verbose=False, python="python3", timeout=60):
+    def __init__(self, host, verbose=False, python="python3", timeout=60, ssh_options=None):
-        self.gateway = execnet.makegateway(f"ssh=root@{host}//python={python}")
+        ssh_options = f"{ssh_options.strip()} " if ssh_options is not None else ""
+        self.gateway = execnet.makegateway(f"ssh={ssh_options}root@{host}//python={python}")
         self._remote_cmdloop_channel = bootstrap_remote(self.gateway, remote)
         self.timeout = timeout
         self.verbose = verbose

cmdeploy/src/cmdeploy/tests/data/zftest.zone

@@ -1,17 +1,18 @@
-; Required DNS entries for chatmail servers
+; Required DNS entries
-zftest.testrun.org.                   A     135.181.204.127
+zftest.testrun.org.                      3600   IN  A      135.181.204.127
-zftest.testrun.org.                   AAAA  2a01:4f9:c012:52f4::1
+zftest.testrun.org.                      3600   IN  AAAA   2a01:4f9:c012:52f4::1
-zftest.testrun.org.                   MX 10 zftest.testrun.org.
+zftest.testrun.org.                      3600   IN  MX     10 zftest.testrun.org.
-_mta-sts.zftest.testrun.org.          TXT "v=STSv1; id=202403211706"
+_mta-sts.zftest.testrun.org.             3600   IN  TXT    "v=STSv1; id=202403211706"
-mta-sts.zftest.testrun.org.           CNAME zftest.testrun.org.
+mta-sts.zftest.testrun.org.              3600   IN  CNAME  zftest.testrun.org.
-www.zftest.testrun.org.               CNAME zftest.testrun.org.
+www.zftest.testrun.org.                  3600   IN  CNAME  zftest.testrun.org.
-opendkim._domainkey.zftest.testrun.org. TXT "v=DKIM1;k=rsa;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoYt82CVUyz2ouaqjX2kB+5J80knAyoOU3MGU5aWppmwUwwTvj/oSTSpkc5JMtVTRmKKr8NUDWAL1Yw7dfGqqPHdHfwwjS3BIvDzYx+hzgtz62RnfNgV+/2MAoNpfX7cAFIHdRzEHNtwugc3RDLquqPoupAE3Y2YRw2T5zG5fILh4vwIcJZL5Uq6B92j8wwJqOex" "33n+vm1NKQ9rxo/UsHAmZlJzpooXcG/4igTBxJyJlamVSRR6N7Nul1v//YJb7J6v2o0iPHW6uE0StzKaPPNC2IVosSRFbD9H2oqppltptFSNPlI0E+t0JBWHem6YK7xcugiO3ImMCaaU8g6Jt/wIDAQAB;s=email;t=s"
+opendkim._domainkey.zftest.testrun.org.  3600   IN  TXT    "v=DKIM1;k=rsa;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoYt82CVUyz2ouaqjX2kB+5J80knAyoOU3MGU5aWppmwUwwTvj/oSTSpkc5JMtVTRmKKr8NUDWAL1Yw7dfGqqPHdHfwwjS3BIvDzYx+hzgtz62RnfNgV+/2MAoNpfX7cAFIHdRzEHNtwugc3RDLquqPoupAE3Y2YRw2T5zG5fILh4vwIcJZL5Uq6B92j8wwJqOex" "33n+vm1NKQ9rxo/UsHAmZlJzpooXcG/4igTBxJyJlamVSRR6N7Nul1v//YJb7J6v2o0iPHW6uE0StzKaPPNC2IVosSRFbD9H2oqppltptFSNPlI0E+t0JBWHem6YK7xcugiO3ImMCaaU8g6Jt/wIDAQAB;s=email;t=s"
+
 ; Recommended DNS entries
-_submission._tcp.zftest.testrun.org.  SRV 0 1 587 zftest.testrun.org.
+zftest.testrun.org.                      3600   IN  TXT    "v=spf1 a ~all"
-_submissions._tcp.zftest.testrun.org. SRV 0 1 465 zftest.testrun.org.
+_dmarc.zftest.testrun.org.               3600   IN  TXT    "v=DMARC1;p=reject;adkim=s;aspf=s"
-_imap._tcp.zftest.testrun.org.        SRV 0 1 143 zftest.testrun.org.
+zftest.testrun.org.                      3600   IN  CAA    0 issue "letsencrypt.org;accounturi=https://acme-v02.api.letsencrypt.org/acme/acct/1371472956"
-_imaps._tcp.zftest.testrun.org.       SRV 0 1 993 zftest.testrun.org.
+_adsp._domainkey.zftest.testrun.org.     3600   IN  TXT    "dkim=discardable"
-zftest.testrun.org.                   CAA 0 issue "letsencrypt.org;accounturi=https://acme-v02.api.letsencrypt.org/acme/acct/1371472956"
+_submission._tcp.zftest.testrun.org.     3600   IN  SRV    0 1 587 zftest.testrun.org.
-zftest.testrun.org.                   TXT "v=spf1 a:zftest.testrun.org ~all"
+_submissions._tcp.zftest.testrun.org.    3600   IN  SRV    0 1 465 zftest.testrun.org.
-_dmarc.zftest.testrun.org.            TXT "v=DMARC1;p=reject;adkim=s;aspf=s"
+_imap._tcp.zftest.testrun.org.           3600   IN  SRV    0 1 143 zftest.testrun.org.
-_adsp._domainkey.zftest.testrun.org.  TXT "dkim=discardable"
+_imaps._tcp.zftest.testrun.org.          3600   IN  SRV    0 1 993 zftest.testrun.org.

cmdeploy/src/cmdeploy/tests/online/test_1_basic.py

@@ -8,6 +8,7 @@ import pytest
 
 from cmdeploy import remote
 from cmdeploy.cmdeploy import get_sshexec
+from cmdeploy.sshexec import FuncError
 
 
 class TestSSHExecutor:
@@ -117,6 +118,33 @@ def test_reject_forged_from(cmsetup, maildata, gencreds, lp, forgeaddr):
     assert "500" in str(e.value)
 
 
+@pytest.mark.slow
+def test_bounces_are_signed(cmsetup, cmsetup2, maildata, sshdomain2):
+    """Test that bounce messages are dkim signed"""
+
+    dkim_rejects_dir = "/tmp/filtermail-rejected/dkim-verify"
+    sshexec2 = get_sshexec(sshdomain2, ssh_options="-oStrictHostKeyChecking=accept-new")
+    sshexec2(call=remote.rdns.shell, kwargs=dict(command=f"rm -rf {dkim_rejects_dir}"))
+
+    our_user = cmsetup.gen_users(1)[0]
+    other_user = cmsetup2.gen_users(1)[0]
+    msg = maildata("encrypted.eml", from_addr=other_user.addr, to_addr=our_user.addr)
+
+    # exceed the 10kB quota of our_user mailbox to trigger a bounce message.
+    def bounce_received():
+        other_user.smtp.sendmail(
+            from_addr=other_user.addr, to_addrs=[our_user.addr], msg=msg.as_string()
+        )
+        out = sshexec2(call=remote.rdns.shell, kwargs=dict(command=f"journalctl -n 5 -u filtermail-incoming"))
+        assert "Filtering unencrypted mail." in out
+
+    try_n_times(20, bounce_received)
+
+    time.sleep(1)
+    # if bounce was dkim-signed, filtermail shouldn't log the eml.
+    with pytest.raises(FuncError):
+        sshexec2(call=remote.rdns.shell, kwargs=dict(command=f"ls {dkim_rejects_dir}"))
+
 def test_authenticated_from(cmsetup, maildata):
     """Test that envelope FROM must be the same as login."""
     user1, user2, user3 = cmsetup.gen_users(3)

cmdeploy/src/cmdeploy/tests/plugin.py

@@ -35,6 +35,11 @@ def pytest_runtest_setup(item):
 
 
 def _get_chatmail_config():
+    inipath = os.environ.get("CHATMAIL_INI")
+    if inipath:
+        path = Path(inipath).resolve()
+        return read_config(path), path
+
     current = Path().resolve()
     while 1:
         path = current.joinpath("chatmail.ini").resolve()
@@ -388,12 +393,15 @@ def cmfactory(rpc, gencreds, maildomain, chatmail_config):
 
 @pytest.fixture
 def remote(sshdomain):
-    return Remote(sshdomain)
+    r = Remote(sshdomain)
+    yield r
+    r.close()
 
 
 class Remote:
     def __init__(self, sshdomain):
         self.sshdomain = sshdomain
+        self._procs = []
 
     def iter_output(self, logcmd="", ready=None):
         getjournal = "journalctl -f" if not logcmd else logcmd
@@ -403,19 +411,32 @@ class Remote:
             case "localhost": command = []
             case _: command = ["ssh", f"root@{self.sshdomain}"]
         [command.append(arg) for arg in getjournal.split()]
-        self.popen = subprocess.Popen(
+        popen = subprocess.Popen(
             command,
+            stdin=subprocess.DEVNULL,
             stdout=subprocess.PIPE,
+            stderr=subprocess.DEVNULL,
         )
-        while 1:
+        self._procs.append(popen)
-            line = self.popen.stdout.readline()
+        try:
-            res = line.decode().strip().lower()
+            while 1:
-            if not res:
+                line = popen.stdout.readline()
-                break
+                res = line.decode().strip().lower()
-            if ready is not None:
+                if not res:
-                ready()
+                    break
-                ready = None
+                if ready is not None:
-            yield res
+                    ready()
+                    ready = None
+                yield res
+        finally:
+            popen.terminate()
+            popen.wait()
+
+    def close(self):
+        while self._procs:
+            proc = self._procs.pop()
+            proc.kill()
+            proc.wait()
 
 
 @pytest.fixture
@@ -435,6 +456,11 @@ def cmsetup(maildomain, gencreds, ssl_context):
     return CMSetup(maildomain, gencreds, ssl_context)
 
 
+@pytest.fixture
+def cmsetup2(maildomain2, gencreds, ssl_context):
+    return CMSetup(maildomain2, gencreds, ssl_context)
+
+
 class CMSetup:
     def __init__(self, maildomain, gencreds, ssl_context):
         self.maildomain = maildomain
@@ -445,7 +471,7 @@ class CMSetup:
         print(f"Creating {num} online users")
         users = []
         for i in range(num):
-            addr, password = self.gencreds()
+            addr, password = self.gencreds(self.maildomain)
             user = CMUser(self.maildomain, addr, password, self.ssl_context)
             assert user.smtp
             users.append(user)

cmdeploy/src/cmdeploy/tests/test_cmdeploy.py

@@ -23,15 +23,19 @@ class TestCmdline:
         run = parser.parse_args(["run"])
         assert init and run
 
-    def test_init_not_overwrite(self, capsys):
+    def test_init_not_overwrite(self, capsys, tmp_path, monkeypatch):
-        assert main(["init", "chat.example.org"]) == 0
+        monkeypatch.delenv("CHATMAIL_INI", raising=False)
+        inipath = tmp_path / "chatmail.ini"
+        args = ["init", "--config", str(inipath), "chat.example.org"]
+        assert main(args) == 0
         capsys.readouterr()
 
-        assert main(["init", "chat.example.org"]) == 1
+        assert main(args) == 1
         out, err = capsys.readouterr()
         assert "path exists" in out.lower()
 
-        assert main(["init", "chat.example.org", "--force"]) == 0
+        args.insert(1, "--force")
+        assert main(args) == 0
         out, err = capsys.readouterr()
         assert "deleting config file" in out.lower()
 

cmdeploy/src/cmdeploy/tests/test_dns.py

@@ -3,7 +3,7 @@ from copy import deepcopy
 import pytest
 
 from cmdeploy import remote
-from cmdeploy.dns import check_full_zone, check_initial_remote_data
+from cmdeploy.dns import check_full_zone, check_initial_remote_data, parse_zone_records
 
 
 @pytest.fixture
@@ -125,18 +125,49 @@ class TestPerformInitialChecks:
         assert not l
 
 
+def test_parse_zone_records():
+    text = """
+    ; This is a comment
+    some.domain. 3600 IN A 1.1.1.1
+
+    ; Another comment
+    www.some.domain. 3600 IN CNAME some.domain.
+
+    ; Multi-word rdata
+    some.domain. 3600 IN MX 10 mail.some.domain.
+
+    ; DKIM record (single line, multi-word TXT rdata)
+    dkim._domainkey.some.domain. 3600 IN TXT "v=DKIM1;k=rsa;p=MIIBIjANBgkqhkiG" "9w0BAQEFAAOCAQ8AMIIBCgKCAQEA"
+
+    ; Another TXT record
+    _dmarc.some.domain. 3600 IN TXT "v=DMARC1;p=reject"
+    """
+    records = list(parse_zone_records(text))
+    assert records == [
+        ("some.domain", "3600", "A", "1.1.1.1"),
+        ("www.some.domain", "3600", "CNAME", "some.domain."),
+        ("some.domain", "3600", "MX", "10 mail.some.domain."),
+        (
+            "dkim._domainkey.some.domain",
+            "3600",
+            "TXT",
+            '"v=DKIM1;k=rsa;p=MIIBIjANBgkqhkiG" "9w0BAQEFAAOCAQ8AMIIBCgKCAQEA"',
+        ),
+        ("_dmarc.some.domain", "3600", "TXT", '"v=DMARC1;p=reject"'),
+    ]
+
+
+def test_parse_zone_records_invalid_line():
+    text = "invalid line"
+    with pytest.raises(ValueError, match="Bad zone record line"):
+        list(parse_zone_records(text))
+
+
 def parse_zonefile_into_dict(zonefile, mockdns_base, only_required=False):
-    for zf_line in zonefile.split("\n"):
+    if only_required:
-        if zf_line.startswith("#"):
+        zonefile = zonefile.split("; Recommended")[0]
-            if "Recommended" in zf_line and only_required:
+    for name, ttl, rtype, rdata in parse_zone_records(zonefile):
-                return
+        mockdns_base.setdefault(rtype, {})[name] = rdata
-            continue
-        if not zf_line.strip():
-            continue
-        zf_domain, zf_typ, zf_value = zf_line.split(maxsplit=2)
-        zf_domain = zf_domain.rstrip(".")
-        zf_value = zf_value.strip()
-        mockdns_base.setdefault(zf_typ, {})[zf_domain] = zf_value
 
 
 class MockSSHExec: