simplify history of nine branch

also incorporates nine.testrun.org user policies

.gitignore

@@ -159,3 +159,5 @@ cython_debug/
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
+
+chatmail.zone

README.md

@@ -1,23 +1,61 @@
-# Chat Mail server configuration
+# Chatmail instances optimized for Delta Chat apps 
 
-This repository setups a ready-to-go chatmail instance
+This repository helps to setup a ready-to-use chatmail instance
 comprised of a minimal setup of the battle-tested 
-[postfix smtp server](https://www.postfix.org) and [dovecot imap server](https://www.dovecot.org).
+[postfix smtp](https://www.postfix.org) and [dovecot imap](https://www.dovecot.org) services. 
 
-## Getting started 
+The setup is designed and optimized for providing chatmail accounts 
+for use by [Delta Chat apps](https://delta.chat).
 
-1. prepare your local system:
+Chatmail accounts are automatically created by a first login, 
+after which the initially specified password is required for using them. 
+
+## Getting Started deploying your own chatmail instance
+
+1. Prepare your local (presumably Linux) system:
 
     scripts/init.sh 
 
-2. set environment variable to the chatmail domain you want to setup:
+2. Setup a domain with `A` and `AAAA` records for your chatmail server.
+
+3. Set environment variable to the chatmail domain you want to setup:
 
     export CHATMAIL_DOMAIN=c1.testrun.org   # replace with your host
 
-3. run the deploy of the chat mail instance: 
+4. Deploy the chat mail instance to your chatmail server: 
 
     scripts/deploy.sh 
 
+   This script uses `pyinfra` and `ssh` to setup packages and configure
+   the chatmail instance on your remote server. 
+
+5. Run `scripts/generate-dns-zone.sh` and 
+   transfer the generated DNS records at your DNS provider
+
+6. Start a Delta Chat app and create a new account 
+   by typing an e-mail address with an arbitrary username 
+   and `@<your-chatmail-domain>` appended. 
+   Use an at least 10-character random password. 
+
+
+### Ports
+
+Postfix listens on ports 25 (smtp) and 587 (submission) and 465 (submissions).
+Dovecot listens on ports 143(imap) and 993 (imaps).
+
+Delta Chat will, however, discover all ports and configurations 
+automatically by reading the `autoconfig.xml` file from the chatmail instance. 
+
+
+## Emergency Commands to disable automatic account creation 
+
+If you need to stop account creation,
+e.g. because some script is wildly creating accounts, run:
+
+    touch /etc/chatmail-nocreate
+
+While this file is present, account creation will be blocked. 
+
 
 ## Running tests and benchmarks (offline and online) 
 
@@ -32,28 +70,26 @@ comprised of a minimal setup of the battle-tested
 
     scripts/bench.sh 
 
-## Running tests (offline and online) 
 
-```
+## Development Background for chatmail instances 
-## Dovecot/Postfix configuration
 
-### Ports
+This repository drives the development of "chatmail instances", 
+comprised of minimal setups of 
 
-Postfix listens on ports 25 (smtp) and 587 (submission) and 465 (submissions).
+- [postfix smtp server](https://www.postfix.org) 
-Dovecot listens on ports 143(imap) and 993 (imaps).
+- [dovecot imap server](https://www.dovecot.org) 
 
-## DNS
+as well as two custom services that are integrated with these two: 
 
-For DKIM you must add a DNS entry as found in /etc/opendkim/selector.txt on your chatmail instance.
+- `chatmaild/src/chatmaild/dictproxy.py` implements 
-The above `scripts/deploy.sh` prints out the DKIM selector and DNS entry you
+  create-on-login account creation semantics and is used
-need to setup with your DNS provider. 
+  by Dovecot during login authentication and by Postfix
+  which in turn uses Dovecot SASL to authenticate users
+  to send mails for them. 
+
+- `chatmaild/src/chatmaild/filtermail.py` prevents 
+  unencrypted e-mail from leaving the chatmail instance
+  and is integrated into postfix's outbound mail pipelines. 
 
-## Emergency Commands
 
-If you need to stop account creation,
-e.g. because some script is wildly creating accounts,
-just run `touch /tmp/nocreate`.
-You can remove the file
-as soon as the attacker was banned
-by different means.
 

chatmaild/src/chatmaild/dictproxy.py

@@ -21,15 +21,40 @@ def encrypt_password(password: str):
     return "{SHA512-CRYPT}" + passhash
 
 
-def create_user(db, user, password):
+def is_allowed_to_create(user, cleartext_password) -> bool:
+    """Return True if user and password are admissable."""
     if os.path.exists(NOCREATE_FILE):
-        logging.warning(
+        logging.warning(f"blocked account creation because {NOCREATE_FILE!r} exists.")
-            f"Didn't create account: {NOCREATE_FILE} exists. Delete the file to enable account creation."
+        return False
-        )
+
-        return
+    if len(cleartext_password) < 10:
+        logging.warning("Password needs to be at least 10 characters long")
+        return False
+
+    parts = user.split("@")
+    if len(parts) != 2:
+        logging.warning(f"user {user!r} is not a proper e-mail address")
+        return False
+    localpart, domain = parts
+
+    if domain == "nine.testrun.org":
+        # nine.testrun.org policy, username has to be exactly nine chars
+        if len(localpart) != 9:
+            logging.warning(f"localpart {localpart!r} has not exactly nine chars")
+            return False
+
+    return True
+
+
+def create_user(db, user, encrypted_password):
     with db.write_transaction() as conn:
-        conn.create_user(user, password)
+        conn.create_user(user, encrypted_password)
-    return dict(home=f"/home/vmail/{user}", uid="vmail", gid="vmail", password=password)
+    return dict(
+        home=f"/home/vmail/{user}",
+        uid="vmail",
+        gid="vmail",
+        password=encrypted_password,
+    )
 
 
 def get_user_data(db, user):
@@ -45,10 +70,13 @@ def lookup_userdb(db, user):
     return get_user_data(db, user)
 
 
-def lookup_passdb(db, user, password):
+def lookup_passdb(db, user, cleartext_password):
     userdata = get_user_data(db, user)
     if not userdata:
-        return create_user(db, user, encrypt_password(password))
+        if not is_allowed_to_create(user, cleartext_password):
+            return
+        encrypted_password = encrypt_password(cleartext_password)
+        userdata = create_user(db=db, user=user, encrypted_password=encrypted_password)
     userdata["password"] = userdata["password"].strip()
     return userdata
 
@@ -72,7 +100,7 @@ def handle_dovecot_request(msg, db, mail_domain):
                     reply_command = "N"
             elif type == "passdb":
                 if user.endswith(f"@{mail_domain}"):
-                    res = lookup_passdb(db, user, password=args[0])
+                    res = lookup_passdb(db, user, cleartext_password=args[0])
                 if res:
                     reply_command = "O"
                 else:

deploy-chatmail/src/deploy_chatmail/__init__.py

@@ -4,8 +4,8 @@ Chat Mail pyinfra deploy.
 import importlib.resources
 from pathlib import Path
 
-from pyinfra import host, logger
+from pyinfra import host
-from pyinfra.operations import apt, files, server, systemd, python
+from pyinfra.operations import apt, files, server, systemd
 from pyinfra.facts.files import File
 from .acmetool import deploy_acmetool
 
@@ -70,6 +70,36 @@ def _configure_opendkim(domain: str, dkim_selector: str) -> bool:
         mode="644",
         config={"domain_name": domain, "opendkim_selector": dkim_selector},
     )
+    need_restart |= main_config.changed
+
+    files.directory(
+        name="Add opendkim directory to /etc",
+        path="/etc/opendkim",
+        user="opendkim",
+        group="opendkim",
+        mode="750",
+        present=True,
+    )
+
+    keytable = files.template(
+        src=importlib.resources.files(__package__).joinpath("opendkim/KeyTable"),
+        dest="/etc/dkimkeys/KeyTable",
+        user="opendkim",
+        group="opendkim",
+        mode="644",
+        config={"domain_name": domain, "opendkim_selector": dkim_selector},
+    )
+    need_restart |= keytable.changed
+
+    signing_table = files.template(
+        src=importlib.resources.files(__package__).joinpath("opendkim/SigningTable"),
+        dest="/etc/dkimkeys/SigningTable",
+        user="opendkim",
+        group="opendkim",
+        mode="644",
+        config={"domain_name": domain, "opendkim_selector": dkim_selector},
+    )
+    need_restart |= signing_table.changed
 
     files.directory(
         name="Add opendkim socket directory to /var/spool/postfix",
@@ -90,8 +120,6 @@ def _configure_opendkim(domain: str, dkim_selector: str) -> bool:
             _sudo_user="opendkim",
         )
 
-    need_restart |= main_config.changed
-
     return need_restart
 
 
@@ -155,6 +183,17 @@ def _configure_dovecot(mail_server: str, debug: bool = False) -> bool:
         mode="644",
     )
 
+    # as per https://doc.dovecot.org/configuration_manual/os/
+    # it is recommended to set the following inotify limits
+    for name in ("max_user_instances", "max_user_watches"):
+        key = f"fs.inotify.{name}"
+        server.sysctl(
+            name=f"Change {key}",
+            key=key,
+            value=65535,
+            persist=True,
+        )
+
     return need_restart
 
 
@@ -238,6 +277,12 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
     opendkim_need_restart = _configure_opendkim(mail_domain, dkim_selector)
     nginx_need_restart = _configure_nginx(mail_domain)
 
+    # deploy web pages and info if we have them
+    pkg_root = importlib.resources.files(__package__)
+    www_path = pkg_root.joinpath(f"../../../www/{mail_domain}").resolve()
+    if www_path.is_dir():
+        files.rsync(f"{www_path}/", "/var/www/html", flags=["-avz"])
+
     systemd.service(
         name="Start and enable OpenDKIM",
         service="opendkim.service",
@@ -292,14 +337,3 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
         enabled=True,
         restarted=journald_conf,
     )
-
-    def callback():
-        result = server.shell(
-            commands=[
-                f"""sed 's/\tIN/ 600 IN/;s/\t(//;s/\"$//;s/^\t  \"//g; s/ ).*//' """
-                f"""/etc/dkimkeys/{dkim_selector}.txt | tr --delete '\n'"""
-            ]
-        )
-        logger.info(f"Add this TXT entry into DNS zone: {result.stdout}")
-
-    python.call(name="Print TXT entry for DKIM", function=callback)

deploy-chatmail/src/deploy_chatmail/deploy.py

@@ -6,7 +6,7 @@ from deploy_chatmail import deploy_chatmail
 def main():
     mail_domain = os.getenv("CHATMAIL_DOMAIN")
     mail_server = os.getenv("CHATMAIL_SERVER", mail_domain)
-    dkim_selector = os.getenv("CHATMAIL_DKIM_SELECTOR", "2023")
+    dkim_selector = os.getenv("CHATMAIL_DKIM_SELECTOR", "dkim")
 
     assert mail_domain
     assert mail_server

deploy-chatmail/src/deploy_chatmail/dovecot/dovecot.conf.j2

@@ -118,6 +118,24 @@ service auth-worker {
   user = vmail
 }
 
+service imap-login {
+    # High-security mode.
+    # Each process serves a single connection and exits afterwards.
+    # This is the default, but we set it explicitly to be sure.
+    # See <https://doc.dovecot.org/admin_manual/login_processes/#high-security-mode> for details.
+    service_count = 1
+
+    # Inrease the number of simultaneous connections.
+    #
+    # As of Dovecot 2.3.19.1 the default is 100 processes.
+    # Combined with `service_count = 1` it means only 100 connections
+    # can be handled simultaneously.
+    process_limit = 10000
+
+    # Avoid startup latency for new connections.
+    process_min_avail = 10
+}
+
 ssl = required
 ssl_cert = </var/lib/acme/live/{{ config.hostname }}/fullchain
 ssl_key = </var/lib/acme/live/{{ config.hostname }}/privkey

deploy-chatmail/src/deploy_chatmail/opendkim/KeyTable

@@ -0,0 +1 @@
+dkim._domainkey.{{ config.domain_name }} {{ config.domain_name }}:{{ config.opendkim_selector }}:/etc/dkimkeys/dkim.private

deploy-chatmail/src/deploy_chatmail/opendkim/SigningTable

@@ -0,0 +1 @@
+*@{{ config.domain_name }} {{ config.opendkim_selector }}._domainkey.{{ config.domain_name }}

deploy-chatmail/src/deploy_chatmail/opendkim/opendkim.conf

@@ -1,7 +1,4 @@
-# This is a basic configuration for signing and verifying. It can easily be
+# OpenDKIM configuration.
-# adapted to suit a basic installation. See opendkim.conf(5) and
-# /usr/share/doc/opendkim/examples/opendkim.conf.sample for complete
-# documentation of available configuration parameters.
 
 Syslog			yes
 SyslogSuccess		yes
@@ -21,7 +18,9 @@ OversignHeaders		From
 # setup options can be found in /usr/share/doc/opendkim/README.opendkim.
 Domain			{{ config.domain_name }}
 Selector		{{ config.opendkim_selector }}
-KeyFile		/etc/dkimkeys/{{ config.opendkim_selector }}.private
+KeyFile		  /etc/dkimkeys/{{ config.opendkim_selector }}.private
+KeyTable          /etc/dkimkeys/KeyTable
+SigningTable      /etc/dkimkeys/SigningTable
 
 # In Debian, opendkim runs as user "opendkim". A umask of 007 is required when
 # using a local socket with MTAs that access the socket as a non-privileged

scripts/bench.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 set -e
 
-online-tests/venv/bin/pytest online-tests/benchmark.py -vrx 
+venv/bin/pytest online-tests/benchmark.py -vrx 

scripts/deploy.sh

@@ -1,10 +1,15 @@
 #!/usr/bin/env bash
-: ${CHATMAIL_DOMAIN:=c1.testrun.org}
-export CHATMAIL_DOMAIN
 
-chatmaild/venv/bin/python3 -m build -n --sdist chatmaild --outdir dist
+echo -----------------------------------------
+echo deploying to $CHATMAIL_DOMAIN 
+echo -----------------------------------------
 
-deploy-chatmail/venv/bin/pyinfra --ssh-user root "$CHATMAIL_DOMAIN" \
+echo WARNING: in five seconds deploy to $CHATMAIL_DOMAIN starts
+sleep 5
+
+venv/bin/python3 -m build -n --sdist chatmaild --outdir dist
+
+venv/bin/pyinfra --ssh-user root "$CHATMAIL_DOMAIN" \
     deploy-chatmail/src/deploy_chatmail/deploy.py
 
 rm -r dist/

scripts/generate-dns-zone.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+: ${CHATMAIL_DOMAIN:=c1.testrun.org}
+: ${CHATMAIL_SSH:=$CHATMAIL_DOMAIN}
+
+set -e
+SSH="ssh root@$CHATMAIL_SSH"
+EMAIL="root@$CHATMAIL_DOMAIN"
+ACME_ACCOUNT_URL="$($SSH -- acmetool account-url)"
+
+cat <<EOF
+$CHATMAIL_DOMAIN. MX 10 $CHATMAIL_DOMAIN.
+$CHATMAIL_DOMAIN. TXT "v=spf1 a:$CHATMAIL_DOMAIN -all"
+_dmarc.$CHATMAIL_DOMAIN. TXT "v=DMARC1;p=reject;rua=mailto:$EMAIL;ruf=mailto:$EMAIL;fo=1;adkim=r;aspf=r"
+_submission._tcp.$CHATMAIL_DOMAIN.  SRV 0 1 587 $CHATMAIL_DOMAIN.
+_submissions._tcp.$CHATMAIL_DOMAIN. SRV 0 1 465 $CHATMAIL_DOMAIN.
+_imap._tcp.$CHATMAIL_DOMAIN.        SRV 0 1 143 $CHATMAIL_DOMAIN.
+_imaps._tcp.$CHATMAIL_DOMAIN.       SRV 0 1 993 $CHATMAIL_DOMAIN.
+$CHATMAIL_DOMAIN. IN CAA 0 issue "letsencrypt.org; accounturi=$ACME_ACCOUNT_URL"
+EOF
+$SSH opendkim-genzone -F | sed 's/^;.*$//;/^$/d'

scripts/test.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
-tox -c chatmaild
+venv/bin/tox -c chatmaild
-tox -c deploy-chatmail
+venv/bin/tox -c deploy-chatmail
 venv/bin/pytest tests/online -vrx --durations=5 $@

tests/chatmaild/test_dictproxy.py

@@ -1,9 +1,10 @@
 import os
+import json
 
 import pytest
 
 import chatmaild.dictproxy
-from chatmaild.dictproxy import get_user_data, lookup_passdb
+from chatmaild.dictproxy import get_user_data, lookup_passdb, handle_dovecot_request
 from chatmaild.database import Database, DBError
 
 
@@ -14,13 +15,13 @@ def db(tmpdir):
     return Database(db_path)
 
 
+
 def test_basic(db):
-    chatmaild.dictproxy.NOCREATE_FILE = "/tmp/nocreate"
+    lookup_passdb(db, "link2xt@c1.testrun.org", "Pieg9aeToe3eghuthe5u")
-    if os.path.exists(chatmaild.dictproxy.NOCREATE_FILE):
-        os.remove(chatmaild.dictproxy.NOCREATE_FILE)
-    lookup_passdb(db, "link2xt@c1.testrun.org", "asdf")
     data = get_user_data(db, "link2xt@c1.testrun.org")
     assert data
+    data2 = lookup_passdb(db, "link2xt@c1.testrun.org", "Pieg9aeToe3eghuthe5u")
+    assert data == data2
 
 
 def test_dont_overwrite_password_on_wrong_login(db):
@@ -32,14 +33,12 @@ def test_dont_overwrite_password_on_wrong_login(db):
     assert res["password"] == res2["password"]
 
 
-def test_nocreate_file(db):
+def test_nocreate_file(db, monkeypatch, tmpdir):
-    chatmaild.dictproxy.NOCREATE_FILE = "/tmp/nocreate"
+    p = tmpdir.join("nocreate")
-    with open(chatmaild.dictproxy.NOCREATE_FILE, "w+") as f:
+    p.write("")
-        f.write("")
+    monkeypatch.setattr(chatmaild.dictproxy, "NOCREATE_FILE", str(p))
-    assert os.path.exists(chatmaild.dictproxy.NOCREATE_FILE)
+    lookup_passdb(db, "newuser1@something.org", "zequ0Aimuchoodaechik")
-    lookup_passdb(db, "newuser1@something.org", "kajdlqweqwe")
     assert not get_user_data(db, "newuser1@something.org")
-    os.remove(chatmaild.dictproxy.NOCREATE_FILE)
 
 
 def test_db_version(db):
@@ -51,3 +50,15 @@ def test_too_high_db_version(db):
         conn.execute("PRAGMA user_version=%s;" % (999,))
     with pytest.raises(DBError):
         db.ensure_tables()
+
+
+def test_handle_dovecot_request(db):
+    msg = ('Lshared/passdb/laksjdlaksjdlaksjdlk12j3l1k2j3123/'
+           'some42@c3.testrun.org\tsome42@c3.testrun.org')
+    res = handle_dovecot_request(msg, db, "c3.testrun.org")
+    assert res
+    assert res[0] == "O" and res.endswith("\n")
+    userdata = json.loads(res[1:].strip())
+    assert userdata["home"] == "/home/vmail/some42@c3.testrun.org"
+    assert userdata["uid"] == userdata["gid"] == "vmail"
+    assert userdata["password"].startswith("{SHA512-CRYPT}")

tests/conftest.py

@@ -195,8 +195,8 @@ def gencreds(maildomain):
             num = next(count)
             alphanumeric = "abcdefghijklmnopqrstuvwxyz1234567890"
             user = "".join(random.choices(alphanumeric, k=10))
-            user = f"ac{num}_{user}"
+            user = f"ac{num}_{user}"[:9]
-            password = "".join(random.choices(alphanumeric, k=10))
+            password = "".join(random.choices(alphanumeric, k=12))
             yield f"{user}@{domain}", f"{password}"
 
     return lambda domain=None: next(gen(domain))

tests/online/test_0_login.py

@@ -23,6 +23,11 @@ def test_login_basic_functioning(imap_or_smtp, gencreds, lp):
     with pytest.raises(imap_or_smtp.AuthError):
         imap_or_smtp.login(user, password + "wrong")
 
+    lp.sec(f"creating users with a short password is not allowed")
+    user, _password = gencreds()
+    with pytest.raises(imap_or_smtp.AuthError):
+        imap_or_smtp.login(user, "admin")
+
 
 def test_login_same_password(imap_or_smtp, gencreds):
     """Test two different users logging in with the same password

www/nine.testrun.org/index.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <title>nine.testrun.org - Experimenting with the Future of Email</title>
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <style>
+        .wrapper {
+            width: 100%;
+            max-width: 596px;
+            margin: 0 auto;
+        }
+
+        .section {
+            width: 100%;
+            max-width: 596px;
+        }
+
+        .text {
+            box-sizing: border-box;
+            padding: 9px;
+            font-size: 18px;
+            font-family: "Courier New", monospace;
+            color: white;
+            background-position: left top;
+            background-image: url(collage-bg.png);
+            background-repeat: no-repeat;
+            background-size: 100% 100%;
+        }
+        h1, h2, h3 {
+            font-size: 16px;
+            font-weight: bold;
+        }
+    </style>
+</head>
+<body>
+    <div class="wrapper">
+        <img class="section" src="collage-top.png" />
+        <div class="section text">
+            <h1>welcome  to nine.testrun.org</h1>
+            <p>
+                to get an account,
+                invent a word with <i>exactly</i> nine characters
+                and append @nine.testrun.org to it.
+                eg. <b>hellofits@nine.testrun.org</b>
+            </p>
+            <p>
+                if the email address is not yet taken, you'll get that account.
+                the first login sets your password.
+                that's it.
+            </p>
+        </div>
+        <img class="section" src="collage-down.png" />
+        <div class="section text">
+            <h1>faq</h1>
+            <p><i>why are other email providers 1000 times more complicated?</i></p>
+            <p>because they want to for $reasons</p>
+        </div>
+    </div>
+</body>
+</html>