dovecot: increase number of simultaneous connections handled by imap-login

Otherwise deltachat core CI running fails with "Connection queue full"
error on IMAP connections.

.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

@@ -10,14 +10,17 @@ comprised of a minimal setup of the battle-tested
 
     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. run the deploy of the chat mail instance: 
 
     scripts/deploy.sh 
 
+5. run `scripts/generate-dns-zone.sh` and create the generated DNS records at your DNS provider
 
 ## Running tests and benchmarks (offline and online) 
 

chatmaild/src/chatmaild/dictproxy.py

@@ -21,15 +21,27 @@ def encrypt_password(password: str):
     return "{SHA512-CRYPT}" + passhash
 
 
-def create_user(db, user, password):
+def check_password(password) -> bool:
+    """Check password policy"""
+    if len(password) < 10:
+        return False
+    return True
+
+
+def create_user(db, user, encrypted_password):
     if os.path.exists(NOCREATE_FILE):
         logging.warning(
             f"Didn't create account: {NOCREATE_FILE} exists. Delete the file to enable account creation."
         )
         return
     with db.write_transaction() as conn:
-        conn.create_user(user, password)
-    return dict(home=f"/home/vmail/{user}", uid="vmail", gid="vmail", password=password)
+        conn.create_user(user, encrypted_password)
+    return dict(
+        home=f"/home/vmail/{user}",
+        uid="vmail",
+        gid="vmail",
+        password=encrypted_password,
+    )
 
 
 def get_user_data(db, user):
@@ -48,6 +60,9 @@ def lookup_userdb(db, user):
 def lookup_passdb(db, user, password):
     userdata = get_user_data(db, user)
     if not userdata:
+        if not check_password(password):
+            logging.warning("Attempt to create an account with a weak password.")
+            return
         return create_user(db, user, encrypt_password(password))
     userdata["password"] = userdata["password"].strip()
     return userdata

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.operations import apt, files, server, systemd, python
+from pyinfra import host
+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
 
 
@@ -292,14 +320,3 @@ 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
-# 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.
+# OpenDKIM configuration.
 
 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
-tox -c deploy-chatmail
+venv/bin/tox -c chatmaild
+venv/bin/tox -c deploy-chatmail
 venv/bin/pytest tests/online -vrx --durations=5 $@

tests/chatmaild/test_dictproxy.py

@@ -18,7 +18,7 @@ def test_basic(db):
     chatmaild.dictproxy.NOCREATE_FILE = "/tmp/nocreate"
     if os.path.exists(chatmaild.dictproxy.NOCREATE_FILE):
         os.remove(chatmaild.dictproxy.NOCREATE_FILE)
-    lookup_passdb(db, "link2xt@c1.testrun.org", "asdf")
+    lookup_passdb(db, "link2xt@c1.testrun.org", "Pieg9aeToe3eghuthe5u")
     data = get_user_data(db, "link2xt@c1.testrun.org")
     assert data
 
@@ -37,7 +37,7 @@ def test_nocreate_file(db):
     with open(chatmaild.dictproxy.NOCREATE_FILE, "w+") as f:
         f.write("")
     assert os.path.exists(chatmaild.dictproxy.NOCREATE_FILE)
-    lookup_passdb(db, "newuser1@something.org", "kajdlqweqwe")
+    lookup_passdb(db, "newuser1@something.org", "zequ0Aimuchoodaechik")
     assert not get_user_data(db, "newuser1@something.org")
     os.remove(chatmaild.dictproxy.NOCREATE_FILE)
 

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