increase number of login connections

.github/workflows/ci.yaml

@@ -10,10 +10,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-        # Checkout pull request HEAD commit instead of merge commit
-        # Otherwise `test_deployed_state` will be unhappy.
-        with:
-          ref: ${{ github.event.pull_request.head.sha }}
 
       - name: run chatmaild tests 
         working-directory: chatmaild

CHANGELOG.md

@@ -2,17 +2,8 @@
 
 ## untagged
 
-- Expire push notification tokens after 90 days
-  ([#583](https://github.com/chatmail/relay/pull/583))
-
-- Use official `mtail` binary instead of `mtail` package
-  ([#581](https://github.com/chatmail/relay/pull/581))
-
-- dovecot: install from download.delta.chat instead of openSUSE Build Service
-  ([#590](https://github.com/chatmail/relay/pull/590))
-
-- Reconfigure Dovecot imap-login service to high-performance mode
-  ([#578](https://github.com/chatmail/relay/pull/578))
+- Increase dovecot imap-login limits
+  ([#577](https://github.com/chatmail/relay/pull/577))
 
 - Increase nginx connection limits
   ([#576](https://github.com/chatmail/relay/pull/576))

README.md

@@ -69,7 +69,7 @@ Please substitute it with your own domain.
     mta-sts.chat.example.com. 3600 IN CNAME chat.example.com.
    ```
 
-2. On your local PC, clone the repository and bootstrap the Python virtualenv.
+2. Clone the repository and bootstrap the Python virtualenv.
 
    ```
     git clone https://github.com/chatmail/relay
@@ -77,29 +77,30 @@ Please substitute it with your own domain.
     scripts/initenv.sh
    ```
 
-3. On your local PC, create chatmail configuration file `chatmail.ini`:
+3. Create chatmail configuration file `chatmail.ini`:
 
    ```
     scripts/cmdeploy init chat.example.org  # <-- use your domain 
    ```
 
-4. Verify that SSH root login to your remote server works:
+4. Verify that SSH root login works:
 
    ```
-    ssh root@chat.example.org  # <-- use your domain 
+    ssh root@chat.example.org   # <-- use your domain 
    ```
 
-5. From your local PC, deploy the remote chatmail relay server:
+
+5. Deploy the remote chatmail relay server:
 
    ```
     scripts/cmdeploy run
    ```
-   This script will also check that you have all necessary DNS records.
+   This script will check that you have all necessary DNS records.
    If DNS records are missing, it will recommend
    which you should configure at your DNS provider
    (it can take some time until they are public).
 
-### Other helpful commands
+### Other helpful commands:
 
 To check the status of your remotely running chatmail service:
 

chatmaild/pyproject.toml

@@ -48,9 +48,6 @@ lint.select = [
   "PLE", # Pylint Error
   "PLW", # Pylint Warning
 ]
-lint.ignore = [
-  "PLC0415" # import-outside-top-level
-]
 
 [tool.tox]
 legacy_tox_ini = """

chatmaild/src/chatmaild/metadata.py

@@ -1,7 +1,5 @@
 import logging
 import sys
-import time
-from contextlib import contextmanager
 
 from .config import read_config
 from .dictproxy import DictProxy
@@ -9,15 +7,8 @@ from .filedict import FileDict
 from .notifier import Notifier
 
 
-def _is_valid_token_timestamp(timestamp, now):
-    # Token if invalid after 90 days
-    # or if the timestamp is in the future.
-    return timestamp > now - 3600 * 24 * 90 and timestamp < now + 60
-
-
 class Metadata:
-    # each SETMETADATA on this key appends to dictionary
-    # mapping of unique device tokens
+    # each SETMETADATA on this key appends to a list of unique device tokens
     # which only ever get removed if the upstream indicates the token is invalid
     DEVICETOKEN_KEY = "devicetoken"
 
@@ -27,51 +18,21 @@ class Metadata:
     def get_metadata_dict(self, addr):
         return FileDict(self.vmail_dir / addr / "metadata.json")
 
-    @contextmanager
-    def _modify_tokens(self, addr):
-        with self.get_metadata_dict(addr).modify() as data:
-            tokens = data.setdefault(self.DEVICETOKEN_KEY, {})
-            now = int(time.time())
-            if isinstance(tokens, list):
-                data[self.DEVICETOKEN_KEY] = tokens = {t: now for t in tokens}
-
-            expired_tokens = [
-                token
-                for token, timestamp in tokens.items()
-                if not _is_valid_token_timestamp(tokens[token], now)
-            ]
-            for expired_token in expired_tokens:
-                del tokens[expired_token]
-
-            yield tokens
-
     def add_token_to_addr(self, addr, token):
-        with self._modify_tokens(addr) as tokens:
-            tokens[token] = int(time.time())
+        with self.get_metadata_dict(addr).modify() as data:
+            tokens = data.setdefault(self.DEVICETOKEN_KEY, [])
+            if token not in tokens:
+                tokens.append(token)
 
     def remove_token_from_addr(self, addr, token):
-        with self._modify_tokens(addr) as tokens:
+        with self.get_metadata_dict(addr).modify() as data:
+            tokens = data.get(self.DEVICETOKEN_KEY, [])
             if token in tokens:
-                del tokens[token]
+                tokens.remove(token)
 
     def get_tokens_for_addr(self, addr):
         mdict = self.get_metadata_dict(addr).read()
-        tokens = mdict.get(self.DEVICETOKEN_KEY, {})
-
-        now = int(time.time())
-        if isinstance(tokens, dict):
-            token_list = [
-                token
-                for token, timestamp in tokens.items()
-                if _is_valid_token_timestamp(timestamp, now)
-            ]
-            if len(token_list) < len(tokens):
-                # Some tokens have expired, remove them.
-                with self._modify_tokens(addr) as _tokens:
-                    pass
-        else:
-            token_list = []
-        return token_list
+        return mdict.get(self.DEVICETOKEN_KEY, [])
 
 
 class MetadataDictProxy(DictProxy):

chatmaild/src/chatmaild/notifier.py

@@ -17,11 +17,11 @@ and which are scheduled for retry using exponential back-off timing.
 If a token notification would be scheduled more than DROP_DEADLINE seconds
 after its first attempt, it is dropped with a log error.
 
-Note that tokens are opaque to the notification machinery here
-and are encrypted foreclosing all ability to distinguish
+Note that tokens are completely opaque to the notification machinery here
+and will in the future be encrypted foreclosing all ability to distinguish
 which device token ultimately goes to which phone-provider notification service,
 or to understand the relation of "device tokens" and chatmail addresses.
-The meaning and format of tokens is basically a matter of chatmail Core and
+The meaning and format of tokens is basically a matter of Delta-Chat Core and
 the `notification.delta.chat` service.
 """
 

cmdeploy/pyproject.toml

@@ -41,6 +41,3 @@ lint.select = [
   "PLE", # Pylint Error
   "PLW", # Pylint Warning
 ]
-lint.ignore = [
-  "PLC0415" # import-outside-top-level
-]

cmdeploy/src/cmdeploy/__init__.py

@@ -318,40 +318,6 @@ def _configure_postfix(config: Config, debug: bool = False) -> bool:
     return need_restart
 
 
-def _install_dovecot_package(package: str, arch: str):
-    arch = "amd64" if arch == "x86_64" else arch
-    arch = "arm64" if arch == "aarch64" else arch
-    url = f"https://download.delta.chat/dovecot/dovecot-{package}_2.3.21%2Bdfsg1-3_{arch}.deb"
-    deb_filename = "/root/" + url.split("/")[-1]
-
-    match (package, arch):
-        case ("core", "amd64"):
-            sha256 = "43f593332e22ac7701c62d58b575d2ca409e0f64857a2803be886c22860f5587"
-        case ("core", "arm64"):
-            sha256 = "4d21eba1a83f51c100f08f2e49f0c9f8f52f721ebc34f75018e043306da993a7"
-        case ("imapd", "amd64"):
-            sha256 = "8d8dc6fc00bbb6cdb25d345844f41ce2f1c53f764b79a838eb2a03103eebfa86"
-        case ("imapd", "arm64"):
-            sha256 = "178fa877ddd5df9930e8308b518f4b07df10e759050725f8217a0c1fb3fd707f"
-        case ("lmtpd", "amd64"):
-            sha256 = "2f69ba5e35363de50962d42cccbfe4ed8495265044e244007d7ccddad77513ab"
-        case ("lmtpd", "arm64"):
-            sha256 = "89f52fb36524f5877a177dff4a713ba771fd3f91f22ed0af7238d495e143b38f"
-        case _:
-            apt.packages(packages=[f"dovecot-{package}"])
-            return
-
-    files.download(
-        name=f"Download dovecot-{package}",
-        src=url,
-        dest=deb_filename,
-        sha256sum=sha256,
-        cache_time=60 * 60 * 24 * 365,  # cache the .deb for a year,
-    )
-
-    apt.deb(name=f"Install dovecot-{package}", src=deb_filename)
-
-
 def _configure_dovecot(config: Config, debug: bool = False) -> bool:
     """Configures Dovecot IMAP server."""
     need_restart = False
@@ -491,26 +457,9 @@ def check_config(config):
 
 
 def deploy_mtail(config):
-    # Uninstall mtail package, we are going to install a static binary.
-    apt.packages(name="Uninstall mtail", packages=["mtail"], present=False)
-
-    (url, sha256sum) = {
-        "x86_64": (
-            "https://github.com/google/mtail/releases/download/v3.0.8/mtail_3.0.8_linux_amd64.tar.gz",
-            "123c2ee5f48c3eff12ebccee38befd2233d715da736000ccde49e3d5607724e4",
-        ),
-        "aarch64": (
-            "https://github.com/google/mtail/releases/download/v3.0.8/mtail_3.0.8_linux_arm64.tar.gz",
-            "aa04811c0929b6754408676de520e050c45dddeb3401881888a092c9aea89cae",
-        ),
-    }[host.get_fact(facts.server.Arch)]
-
-    server.shell(
-        name="Download mtail",
-        commands=[
-            f"(echo '{sha256sum} /usr/local/bin/mtail' | sha256sum -c) || (curl -L {url} | gunzip | tar -x -f - mtail -O >/usr/local/bin/mtail.new && mv /usr/local/bin/mtail.new /usr/local/bin/mtail)",
-            "chmod 755 /usr/local/bin/mtail",
-        ],
+    apt.packages(
+        name="Install mtail",
+        packages=["mtail"],
     )
 
     # Using our own systemd unit instead of `/usr/lib/systemd/system/mtail.service`.
@@ -646,7 +595,7 @@ def deploy_chatmail(config_path: Path, disable_mail: bool) -> None:
         path="/etc/apt/sources.list",
         line="deb [signed-by=/etc/apt/keyrings/obs-home-deltachat.gpg] https://download.opensuse.org/repositories/home:/deltachat/Debian_12/ ./",
         escape_regex_characters=True,
-        present=False,
+        ensure_newline=True,
     )
 
     if host.get_fact(Port, port=53) != "unbound":
@@ -709,9 +658,10 @@ def deploy_chatmail(config_path: Path, disable_mail: bool) -> None:
         packages="postfix",
     )
 
-    _install_dovecot_package("core", host.get_fact(facts.server.Arch))
-    _install_dovecot_package("imapd", host.get_fact(facts.server.Arch))
-    _install_dovecot_package("lmtpd", host.get_fact(facts.server.Arch))
+    apt.packages(
+        name="Install Dovecot",
+        packages=["dovecot-imapd", "dovecot-lmtpd"],
+    )
 
     apt.packages(
         name="Install nginx",

cmdeploy/src/cmdeploy/dovecot/dovecot.conf.j2

@@ -177,34 +177,23 @@ service auth-worker {
 }
 
 service imap-login {
-    # High-performance mode as described in
-    # <https://doc.dovecot.org/2.3/admin_manual/login_processes/#high-performance-mode>
-    #
-    # So-called high-security mode described in
-    # <https://doc.dovecot.org/2.3/admin_manual/login_processes/#high-security-mode>
-    # and enabled by default with `service_count = 1` starts one process per connection
-    # and has problems logging in thousands of users after Dovecot restart.
-    service_count = 0
+    # We are not using "high-security-mode" because even if dovecot
+    # login would be compromised, there are only E2EE messages to be
+    # found or sent, and an attacker doesn't have the key used with this address. 
+    # See <https://doc.dovecot.org/admin_manual/login_processes/#high-security-mode> for details.
+    
+    # Performance Mode. Each process serves up to 100 connections and exits afterwards. 
+    service_count = 100
 
-    # Increase virtual memory size limit.
-    # Since imap-login processes handle TLS connections
-    # even after logging users in
-    # and many connections are handled by each process,
-    # memory size limit should be increased.
+    # Inrease the number of simultaneous connections.
     #
-    # Otherwise the whole process eventually dies
-    # with an error similar to
-    #   imap-login: Fatal: master: service(imap-login):
-    #   child 1422951 returned error 83
-    #   (Out of memory (service imap-login { vsz_limit=256 MB },
-    #    you may need to increase it)
-    # and takes down all its TLS connections at once.
-    vsz_limit = 1G
+    # 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.
+    # We allow up to 5000 * 100 = 500K connections 
+    process_limit = 10000
 
     # Avoid startup latency for new connections.
-    #
-    # Should be set to at least the number of CPU cores
-    # according to the documentation.
     process_min_avail = 10
 }
 

cmdeploy/src/cmdeploy/mtail/mtail.service.j2

@@ -3,7 +3,7 @@ Description=mtail
 
 [Service]
 Type=simple
-ExecStart=/bin/sh -c "journalctl -f -o short-iso -n 0 | /usr/local/bin/mtail --address={{ address }} --port={{ port }} --progs /etc/mtail --logtostderr --logs -"
+ExecStart=/bin/sh -c "journalctl -f -o short-iso -n 0 | /usr/bin/mtail --address={{ address }} --port={{ port }} --progs /etc/mtail --logtostderr --logs /dev/stdin"
 Restart=on-failure
 
 [Install]

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

@@ -1,6 +1,5 @@
 import datetime
 import smtplib
-import socket
 import subprocess
 
 import pytest
@@ -119,19 +118,14 @@ def test_authenticated_from(cmsetup, maildata):
 
 @pytest.mark.parametrize("from_addr", ["fake@example.org", "fake@testrun.org"])
 def test_reject_missing_dkim(cmsetup, maildata, from_addr):
-    domain = cmsetup.maildomain
-    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    sock.settimeout(10)
-    try:
-        sock.connect((domain, 25))
-    except socket.timeout:
-        pytest.skip(f"port 25 not reachable for {domain}")
-
     recipient = cmsetup.gen_users(1)[0]
     msg = maildata(
         "encrypted.eml", from_addr=from_addr, to_addr=recipient.addr
     ).as_string()
-    conn = smtplib.SMTP(cmsetup.maildomain, 25, timeout=10)
+    try:
+        conn = smtplib.SMTP(cmsetup.maildomain, 25, timeout=10)
+    except TimeoutError:
+        pytest.skip(f"port 25 not reachable for {cmsetup.maildomain}")
 
     with conn as s:
         with pytest.raises(smtplib.SMTPDataError, match="No valid DKIM signature"):