tests: add rate limit tests

chatmaild/src/chatmaild/dictproxy.py

@@ -59,7 +59,7 @@ def lookup_passdb(db, user, password):
     return userdata
 
 
-def handle_dovecot_request(msg, db, mail_domain):
+def handle_dovecot_request(msg, db):
     print(f"received msg: {msg!r}", file=sys.stderr)
     short_command = msg[0]
     if short_command == "L":  # LOOKUP
@@ -70,15 +70,13 @@ def handle_dovecot_request(msg, db, mail_domain):
         res = ""
         if namespace == "shared":
             if type == "userdb":
-                if user.endswith(f"@{mail_domain}"):
-                    res = lookup_userdb(db, user)
+                res = lookup_userdb(db, user)
                 if res:
                     reply_command = "O"
                 else:
                     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, password=args[0])
                 if res:
                     reply_command = "O"
                 else:
@@ -97,8 +95,6 @@ def main():
     socket = sys.argv[1]
     passwd_entry = pwd.getpwnam(sys.argv[2])
     db = Database(sys.argv[3])
-    with open("/etc/mailname", "r") as fp:
-        mail_domain = fp.read().strip()
 
     class Handler(StreamRequestHandler):
         def handle(self):
@@ -106,7 +102,7 @@ def main():
                 msg = self.rfile.readline().strip().decode()
                 if not msg:
                     break
-                res = handle_dovecot_request(msg, db, mail_domain)
+                res = handle_dovecot_request(msg, db)
                 if res:
                     print(f"sending result: {res!r}", file=sys.stderr)
                     self.wfile.write(res.encode("ascii"))

deploy-chatmail/src/deploy_chatmail/__init__.py

@@ -173,33 +173,6 @@ def _configure_dovecot(mail_server: str, debug: bool = False) -> bool:
     return need_restart
 
 
-def _configure_nginx(domain: str, debug: bool = False) -> bool:
-    """Configures nginx HTTP server."""
-    need_restart = False
-
-    main_config = files.template(
-        src=importlib.resources.files(__package__).joinpath("nginx.conf.j2"),
-        dest="/etc/nginx/nginx.conf",
-        user="root",
-        group="root",
-        mode="644",
-        config={"domain_name": domain},
-    )
-    need_restart |= main_config.changed
-
-    autoconfig = files.template(
-        src=importlib.resources.files(__package__).joinpath("autoconfig.xml.j2"),
-        dest="/var/www/html/.well-known/autoconfig/mail/config-v1.1.xml",
-        user="root",
-        group="root",
-        mode="644",
-        config={"domain_name": domain},
-    )
-    need_restart |= autoconfig.changed
-
-    return need_restart
-
-
 def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> None:
     """Deploy a chat-mail instance.
 
@@ -221,7 +194,7 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
     )
 
     # Deploy acmetool to have TLS certificates.
-    deploy_acmetool(nginx_hook=True, domains=[mail_server])
+    deploy_acmetool(domains=[mail_server])
 
     apt.packages(
         name="Install Postfix",
@@ -241,17 +214,11 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
         ],
     )
 
-    apt.packages(
-        name="Install nginx",
-        packages=["nginx"],
-    )
-
     _install_chatmaild()
     debug = False
     dovecot_need_restart = _configure_dovecot(mail_server, debug=debug)
     postfix_need_restart = _configure_postfix(mail_domain, debug=debug)
     opendkim_need_restart = _configure_opendkim(mail_domain, dkim_selector)
-    nginx_need_restart = _configure_nginx(mail_domain)
 
     systemd.service(
         name="Start and enable OpenDKIM",
@@ -277,21 +244,6 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
         restarted=dovecot_need_restart,
     )
 
-    systemd.service(
-        name="Start and enable nginx",
-        service="nginx.service",
-        running=True,
-        enabled=True,
-        restarted=nginx_need_restart,
-    )
-
-    # This file is used by auth proxy.
-    # https://wiki.debian.org/EtcMailName
-    server.shell(
-        name="Setup /etc/mailname",
-        commands=[f"echo {mail_domain} >/etc/mailname; chmod 644 /etc/mailname"],
-    )
-
     def callback():
         result = server.shell(
             commands=[

deploy-chatmail/src/deploy_chatmail/acmetool/__init__.py

@@ -38,13 +38,22 @@ def deploy_acmetool(nginx_hook=False, email="", domains=[]):
         email=email,
     )
 
-    files.template(
-        src=importlib.resources.files(__package__).joinpath("target.yaml.j2"),
-        dest="/var/lib/acme/conf/target",
+    service_file = files.put(
+        src=importlib.resources.files(__package__)
+        .joinpath("acmetool-redirector.service")
+        .open("rb"),
+        dest="/etc/systemd/system/acmetool-redirector.service",
         user="root",
         group="root",
         mode="644",
     )
+    systemd.service(
+        name="Setup acmetool-redirector service",
+        service="acmetool-redirector.service",
+        running=False,
+        enabled=False,
+        restarted=service_file.changed,
+    )
 
     for domain in domains:
         server.shell(

deploy-chatmail/src/deploy_chatmail/acmetool/acmetool-redirector.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=acmetool HTTP redirector
+
+[Service]
+Type=notify
+ExecStart=/usr/bin/acmetool redirector --service.uid=daemon
+Restart=always
+RestartSec=30
+
+[Install]
+WantedBy=multi-user.target

deploy-chatmail/src/deploy_chatmail/acmetool/target.yaml.j2

@@ -1,7 +0,0 @@
-request:
-  provider: https://acme-v02.api.letsencrypt.org/directory
-  key:
-    type: rsa
-  challenge:
-    webroot-paths:
-    - /var/www/html/.well-known/acme-challenge

deploy-chatmail/src/deploy_chatmail/autoconfig.xml.j2

@@ -1,37 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-
-<clientConfig version="1.1">
-  <emailProvider id="{{ config.domain_name }}">
-    <domain>{{ config.domain_name }}</domain>
-    <displayName>{{ config.domain_name }} chatmail</displayName>
-    <displayShortName>{{ config.domain_name }}</displayShortName>
-    <incomingServer type="imap">
-      <hostname>{{ config.domain_name }}</hostname>
-      <port>993</port>
-      <socketType>SSL</socketType>
-      <authentication>password-cleartext</authentication>
-      <username>%EMAILADDRESS%</username>
-    </incomingServer>
-    <incomingServer type="imap">
-      <hostname>{{ config.domain_name }}</hostname>
-      <port>143</port>
-      <socketType>STARTTLS</socketType>
-      <authentication>password-cleartext</authentication>
-      <username>%EMAILADDRESS%</username>
-    </incomingServer>
-    <outgoingServer type="smtp">
-      <hostname>{{ config.domain_name }}</hostname>
-      <port>465</port>
-      <socketType>SSL</socketType>
-      <authentication>password-cleartext</authentication>
-      <username>%EMAILADDRESS%</username>
-    </outgoingServer>
-    <outgoingServer type="smtp">
-      <hostname>{{ config.domain_name }}</hostname>
-      <port>587</port>
-      <socketType>STARTTLS</socketType>
-      <authentication>password-cleartext</authentication>
-      <username>%EMAILADDRESS%</username>
-    </outgoingServer>
-  </emailProvider>
-</clientConfig>

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

@@ -1,47 +0,0 @@
-user www-data;
-worker_processes auto;
-pid /run/nginx.pid;
-error_log /var/log/nginx/error.log;
-
-events {
-	worker_connections 768;
-	# multi_accept on;
-}
-
-http {
-	sendfile on;
-	tcp_nopush on;
-
-	# Do not emit nginx version on error pages.
-	server_tokens off;
-
-	include /etc/nginx/mime.types;
-	default_type application/octet-stream;
-
-	ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;
-	ssl_prefer_server_ciphers on;
-	ssl_certificate /var/lib/acme/live/{{ config.domain_name }}/fullchain;
-	ssl_certificate_key /var/lib/acme/live/{{ config.domain_name }}/privkey;
-
-	gzip on;
-
-	server {
-		listen 80 default_server;
-		listen [::]:80 default_server;
-		listen 443 ssl default_server;
-		listen [::]:443 ssl default_server;
-
-		root /var/www/html;
-
-		index index.html index.htm;
-
-		server_name _;
-
-		location / {
-			# First attempt to serve request as file, then
-			# as directory, then fall back to displaying a 404.
-			try_files $uri $uri/ =404;
-		}
-	}
-}
-

online-tests/test_0_login.py

@@ -1,3 +1,5 @@
+import smtplib
+
 import pytest
 
 
@@ -34,3 +36,296 @@ def test_login_same_password(imap_or_smtp, gencreds):
     imap_or_smtp.login(user1, password1)
     imap_or_smtp.connect()
     imap_or_smtp.login(user2, password1)
+
+
+@pytest.mark.parametrize(
+    ("authenticated", "existing_from", "outside_to", "log_msg"),
+    [
+        (False, False, False, "Sending message with forged FROM of chatmail user to chatmail user"),
+        (False, True, False, "Sending message with forged FROM of outside user to chatmail user"),
+        (False, False, True, "Sending message with forged FROM of chatmail user to outside user"),
+        (False, True, True, "Sending message with forged FROM of outside user to outside user"),
+        (True, False, False, "Sending authenticated message with forged FROM of chatmail user to chatmail user"),
+        (True, True, False, "Sending authenticated message with forged FROM of outside user to chatmail user"),
+        (True, False, True, "Sending authenticated message with forged FROM of chatmail user to outside user"),
+        (True, True, True, "Sending authenticated message with forged FROM of outside user to outside user"),
+    ]
+)
+def test_send_with_forged_from(smtp, gencreds, lp, authenticated, existing_from, outside_to, log_msg):
+    """Test that users can't impersonate each other."""
+    if outside_to:
+        to_addr = "recipient@example.org"
+    else:
+        to_addr, password = gencreds()
+        smtp.connect()
+        smtp.login(to_addr, password)
+        smtp.conn.close()
+
+    if existing_from:
+        from_addr, password = gencreds()
+        smtp.connect()
+        smtp.login(from_addr, password)
+        smtp.conn.close()
+    else:
+        from_addr = f"9d8znohcoimafiilvsjfovaniufsmdj@{smtp.host}"
+
+    smtp.connect()
+    if authenticated:
+        attacker_addr, password = gencreds()
+        smtp.login(attacker_addr, password)
+
+    mail = "\r\n".join([
+        "Subject: ...",
+        f"From: <{from_addr}>",
+        f"To: <{to_addr}>",
+        "Date: Sun, 15 Oct 2023 16:43:21 +0000",
+        "Message-ID: <Mr.UVyJWZmkCKM.hGzNc6glBE_@c2.testrun.org>",
+        "In-Reply-To: <Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+        "References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
+        "\t<Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+        "Chat-Version: 1.0",
+        f"Autocrypt: addr={from_addr}; prefer-encrypt=mutual;",
+        "\tkeydata=xjMEZSwWjhYJKwYBBAHaRw8BAQdAQBEhqeJh0GueHB6kF/DUQqYCxARNBVokg/AzT+7LqH",
+        "\trNFzxiYXJiYXpAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUsFo4CGwMECwkIBwYVCAkKCwID",
+        "\tFgIBFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX9A4AEAnHWHp49eBCMHK5t66gYPiW",
+        "\tXQuB1mwUjzGfYWB+0RXUoA/0xcQ3FbUNlGKW7Blp6eMFfViv6Mv2d3kNSXACB6nmcMzjgEZSwWjhIK",
+        "\tKwYBBAGXVQEFAQEHQBpY5L2M1XHo0uxf8SX1wNLBp/OVvidoWHQF2Jz+kJsUAwEIB8J4BBgWCAAgBQ",
+        "\tJlLBaOAhsMFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX/INgEA37AJaNvruYsJVanP",
+        "\tIXnYw4CKd55UAwl8Zcy+M2diAbkA/0fHHcGV4r78hpbbL1Os52DPOdqYQRauIeJUeG+G6bQO",
+        "MIME-Version: 1.0",
+        'Content-Type: multipart/encrypted; protocol="application/pgp-encrypted";',
+        '\tboundary="YFrteb74qSXmggbOxZL9dRnhymywAi"',
+        "",
+        "",
+        "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+        "Content-Description: PGP/MIME version identification",
+        "Content-Type: application/pgp-encrypted",
+        "",
+        "Version: 1",
+        "",
+        "",
+        "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+        "Content-Description: OpenPGP encrypted message",
+        'Content-Disposition: inline; filename="encrypted.asc";',
+        'Content-Type: application/octet-stream; name="encrypted.asc"',
+        "",
+        "-----BEGIN PGP MESSAGE-----",
+        "",
+        "wU4DhW3gBZ/VvCYSAQdA8bMs2spwbKdGjVsL1ByPkNrqD7frpB73maeL6I6SzDYg",
+        "O5G53tv339RdKq3WRcCtEEvxjHlUx2XNwXzC04BpmfvBTgNfPUyLDzjXnxIBB0Ae",
+        "8ymwGvXMCCimHXN0Dg8Ui62KOi03h0UgheoHWovJSCDF4CKre/xtFr3nL7lq/PKI",
+        "JsjVNz7/RK9FSXF6WwfONtLCyQGEuVAsB/KXfCBEyfKhaMwGHvhujRidGW5uV1no",
+        "lMGl3ODmo29Lgeu2uSE7EpJRZoe6hU6ddmBkqxax61ZtkaFlGFFpdo2K8balNNdz",
+        "ZsJ/9mmI9x3oOJ4/l1nhQbUO9ADbs7gJhFdV5Qkp30b5fCI7bU+aoe1ccBbLe/WM",
+        "YUty1PqcuQT7XjA+XmYuL261tvW8pBetT+i33/E2d8PzzYt2IuK9qeevyS+yxdwA",
+        "kfwejFWzzsUlJaDxs1x4XOxkMgSj+jo+g12dFOb7fyClsAnq23iDb8AuaT/BScAI",
+        "+lO+gher69+6LmM7VGHLG5k762J1jTaQCaKt1s8TAWV99Eo4491vL6fyvk3l/Cfg",
+        "RXSwiWFgj19Pn0Rq7CD9v22UE2vdUMBTcV4aw79mClk1YQ23jbF0y5DCjPdJ62Zo",
+        "tskBgFt3NoWV80jZ76zIBLrrjLwCCll8JjJtFwSkt2GX5RFBsVa4A8IDht9RtEk7",
+        "rrHgbSZQfkauEi/mH3/6CDZoLqSHudUZ7d4MaJwun1TkFYGe2ORwGJd4OBj3oGJp",
+        "H8YBwCpk///L/fKjX0Gg3M8nrpM4wrRFhPKidAgO/kcm25X4+ZHlVkWBTCt5RWKI",
+        "fHh6oLDZCqCfcgMkE1KKmwfIHaUkhq5BPRigwy6i5dh1DM4+1UCLh3dxzVbqE9b9",
+        "61NB19nXdRtDA2sOUnj9ve6m/wEPyCb6/zBQZqvCBYb1/AjdXpUrFT+DbpfyxaXN",
+        "XfhDVb5mNqNM/IVj0V5fvTc6vOfYbzQtPm10H+FdWWfb+rJRfyC3MA2w2IqstFe3",
+        "w3bu2iE6CQvSqRvge+ZqLKt/NqYwOURiUmpuklbl3kPJ97+mfKWoiqk8Iz1VY+bb",
+        "NMUC7aoGv+jcoj+WS6PYO8N6BeRVUUB3ZJSf8nzjgxm1/BcM+UD3BPrlhT11ODRs",
+        "baifGbprMWwt3dhb8cQgRT8GPdpO1OsDkzL6iikMjLHWWiA99GV6ruiHsIPw6boW",
+        "A6/uSOskbDHOROotKmddGTBd0iiHXAoQsJFt1ZjUkt6EHrgWs+GAvrvKpXs1mrz8",
+        "uj3GwEFrHS+Xuf2UDgpszYT3hI2cL/kUtGakVR7m7vVMZqXBUbZdGAEb1PZNPwsI",
+        "E4aMK02+EVB+tSN4Fzj99N2YD0inVYt+oPjr2tHhUS6aSGBNS/48Ki47DOg4Sxkn",
+        "lkOWnEbCD+XTnbDd",
+        "=agR5",
+        "-----END PGP MESSAGE-----",
+        "",
+        "",
+        "--YFrteb74qSXmggbOxZL9dRnhymywAi--",
+        "",
+        "",
+    ]).encode()
+
+    if not authenticated:
+        smtperror = smtplib.SMTPRecipientsRefused
+    else:
+        smtperror = smtplib.SMTPException
+
+    lp.sec(log_msg)
+    with pytest.raises(smtperror):
+        smtp.conn.sendmail(from_addr, to_addr, mail)
+
+
+def test_no_internal_rate_limit(smtp, gencreds):
+    """Test that there is no rate limit between accounts on the same chatmail server."""
+    to_addr, password = gencreds()
+    smtp.connect()
+    smtp.login(to_addr, password)
+
+    user, password = gencreds()
+    smtp.connect()
+    smtp.login(user, password)
+
+    mail = "\r\n".join(
+        [
+            "Subject: ...",
+            f"From: <{user}>",
+            f"To: <{to_addr}>",
+            "Date: Sun, 15 Oct 2023 16:43:21 +0000",
+            "Message-ID: <Mr.UVyJWZmkCKM.hGzNc6glBE_@c2.testrun.org>",
+            "In-Reply-To: <Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+            "References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
+            "\t<Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+            "Chat-Version: 1.0",
+            f"Autocrypt: addr={user}; prefer-encrypt=mutual;",
+            "\tkeydata=xjMEZSwWjhYJKwYBBAHaRw8BAQdAQBEhqeJh0GueHB6kF/DUQqYCxARNBVokg/AzT+7LqH",
+            "\trNFzxiYXJiYXpAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUsFo4CGwMECwkIBwYVCAkKCwID",
+            "\tFgIBFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX9A4AEAnHWHp49eBCMHK5t66gYPiW",
+            "\tXQuB1mwUjzGfYWB+0RXUoA/0xcQ3FbUNlGKW7Blp6eMFfViv6Mv2d3kNSXACB6nmcMzjgEZSwWjhIK",
+            "\tKwYBBAGXVQEFAQEHQBpY5L2M1XHo0uxf8SX1wNLBp/OVvidoWHQF2Jz+kJsUAwEIB8J4BBgWCAAgBQ",
+            "\tJlLBaOAhsMFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX/INgEA37AJaNvruYsJVanP",
+            "\tIXnYw4CKd55UAwl8Zcy+M2diAbkA/0fHHcGV4r78hpbbL1Os52DPOdqYQRauIeJUeG+G6bQO",
+            "MIME-Version: 1.0",
+            'Content-Type: multipart/encrypted; protocol="application/pgp-encrypted";',
+            '\tboundary="YFrteb74qSXmggbOxZL9dRnhymywAi"',
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+            "Content-Description: PGP/MIME version identification",
+            "Content-Type: application/pgp-encrypted",
+            "",
+            "Version: 1",
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+            "Content-Description: OpenPGP encrypted message",
+            'Content-Disposition: inline; filename="encrypted.asc";',
+            'Content-Type: application/octet-stream; name="encrypted.asc"',
+            "",
+            "-----BEGIN PGP MESSAGE-----",
+            "",
+            "wU4DhW3gBZ/VvCYSAQdA8bMs2spwbKdGjVsL1ByPkNrqD7frpB73maeL6I6SzDYg",
+            "O5G53tv339RdKq3WRcCtEEvxjHlUx2XNwXzC04BpmfvBTgNfPUyLDzjXnxIBB0Ae",
+            "8ymwGvXMCCimHXN0Dg8Ui62KOi03h0UgheoHWovJSCDF4CKre/xtFr3nL7lq/PKI",
+            "JsjVNz7/RK9FSXF6WwfONtLCyQGEuVAsB/KXfCBEyfKhaMwGHvhujRidGW5uV1no",
+            "lMGl3ODmo29Lgeu2uSE7EpJRZoe6hU6ddmBkqxax61ZtkaFlGFFpdo2K8balNNdz",
+            "ZsJ/9mmI9x3oOJ4/l1nhQbUO9ADbs7gJhFdV5Qkp30b5fCI7bU+aoe1ccBbLe/WM",
+            "YUty1PqcuQT7XjA+XmYuL261tvW8pBetT+i33/E2d8PzzYt2IuK9qeevyS+yxdwA",
+            "kfwejFWzzsUlJaDxs1x4XOxkMgSj+jo+g12dFOb7fyClsAnq23iDb8AuaT/BScAI",
+            "+lO+gher69+6LmM7VGHLG5k762J1jTaQCaKt1s8TAWV99Eo4491vL6fyvk3l/Cfg",
+            "RXSwiWFgj19Pn0Rq7CD9v22UE2vdUMBTcV4aw79mClk1YQ23jbF0y5DCjPdJ62Zo",
+            "tskBgFt3NoWV80jZ76zIBLrrjLwCCll8JjJtFwSkt2GX5RFBsVa4A8IDht9RtEk7",
+            "rrHgbSZQfkauEi/mH3/6CDZoLqSHudUZ7d4MaJwun1TkFYGe2ORwGJd4OBj3oGJp",
+            "H8YBwCpk///L/fKjX0Gg3M8nrpM4wrRFhPKidAgO/kcm25X4+ZHlVkWBTCt5RWKI",
+            "fHh6oLDZCqCfcgMkE1KKmwfIHaUkhq5BPRigwy6i5dh1DM4+1UCLh3dxzVbqE9b9",
+            "61NB19nXdRtDA2sOUnj9ve6m/wEPyCb6/zBQZqvCBYb1/AjdXpUrFT+DbpfyxaXN",
+            "XfhDVb5mNqNM/IVj0V5fvTc6vOfYbzQtPm10H+FdWWfb+rJRfyC3MA2w2IqstFe3",
+            "w3bu2iE6CQvSqRvge+ZqLKt/NqYwOURiUmpuklbl3kPJ97+mfKWoiqk8Iz1VY+bb",
+            "NMUC7aoGv+jcoj+WS6PYO8N6BeRVUUB3ZJSf8nzjgxm1/BcM+UD3BPrlhT11ODRs",
+            "baifGbprMWwt3dhb8cQgRT8GPdpO1OsDkzL6iikMjLHWWiA99GV6ruiHsIPw6boW",
+            "A6/uSOskbDHOROotKmddGTBd0iiHXAoQsJFt1ZjUkt6EHrgWs+GAvrvKpXs1mrz8",
+            "uj3GwEFrHS+Xuf2UDgpszYT3hI2cL/kUtGakVR7m7vVMZqXBUbZdGAEb1PZNPwsI",
+            "E4aMK02+EVB+tSN4Fzj99N2YD0inVYt+oPjr2tHhUS6aSGBNS/48Ki47DOg4Sxkn",
+            "lkOWnEbCD+XTnbDd",
+            "=agR5",
+            "-----END PGP MESSAGE-----",
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi--",
+            "",
+            "",
+        ]
+    ).encode()
+    for i in range(100):
+        print("Sending mail", str(i))
+        smtp.conn.sendmail(user, to_addr, mail)
+
+
+@pytest.mark.xfail(reason="No rate limit at the moment")
+def test_exceed_rate_limit(smtp, gencreds):
+    """Test that the outbound rate limit is exceeded if we send a lot of messages at once."""
+    user, password = gencreds()
+    smtp.connect()
+    smtp.login(user, password)
+
+    to_addr = "foobar@example.org"
+    mail = "\r\n".join(
+        [
+            "Subject: ...",
+            f"From: <{user}>",
+            f"To: <{to_addr}>",
+            "Date: Sun, 15 Oct 2023 16:43:21 +0000",
+            "Message-ID: <Mr.UVyJWZmkCKM.hGzNc6glBE_@c2.testrun.org>",
+            "In-Reply-To: <Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+            "References: <Mr.3gckbNy5bch.uK3Hd2Ws6-w@c2.testrun.org>",
+            "\t<Mr.MvmCz-GQbi_.6FGRkhDf05c@c2.testrun.org>",
+            "Chat-Version: 1.0",
+            f"Autocrypt: addr={user}; prefer-encrypt=mutual;",
+            "\tkeydata=xjMEZSwWjhYJKwYBBAHaRw8BAQdAQBEhqeJh0GueHB6kF/DUQqYCxARNBVokg/AzT+7LqH",
+            "\trNFzxiYXJiYXpAYzIudGVzdHJ1bi5vcmc+wosEEBYIADMCGQEFAmUsFo4CGwMECwkIBwYVCAkKCwID",
+            "\tFgIBFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX9A4AEAnHWHp49eBCMHK5t66gYPiW",
+            "\tXQuB1mwUjzGfYWB+0RXUoA/0xcQ3FbUNlGKW7Blp6eMFfViv6Mv2d3kNSXACB6nmcMzjgEZSwWjhIK",
+            "\tKwYBBAGXVQEFAQEHQBpY5L2M1XHo0uxf8SX1wNLBp/OVvidoWHQF2Jz+kJsUAwEIB8J4BBgWCAAgBQ",
+            "\tJlLBaOAhsMFiEEFTfUNvVnY3b9F7yHnmme1PfUhX8ACgkQnmme1PfUhX/INgEA37AJaNvruYsJVanP",
+            "\tIXnYw4CKd55UAwl8Zcy+M2diAbkA/0fHHcGV4r78hpbbL1Os52DPOdqYQRauIeJUeG+G6bQO",
+            "MIME-Version: 1.0",
+            'Content-Type: multipart/encrypted; protocol="application/pgp-encrypted";',
+            '\tboundary="YFrteb74qSXmggbOxZL9dRnhymywAi"',
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+            "Content-Description: PGP/MIME version identification",
+            "Content-Type: application/pgp-encrypted",
+            "",
+            "Version: 1",
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi",
+            "Content-Description: OpenPGP encrypted message",
+            'Content-Disposition: inline; filename="encrypted.asc";',
+            'Content-Type: application/octet-stream; name="encrypted.asc"',
+            "",
+            "-----BEGIN PGP MESSAGE-----",
+            "",
+            "wU4DhW3gBZ/VvCYSAQdA8bMs2spwbKdGjVsL1ByPkNrqD7frpB73maeL6I6SzDYg",
+            "O5G53tv339RdKq3WRcCtEEvxjHlUx2XNwXzC04BpmfvBTgNfPUyLDzjXnxIBB0Ae",
+            "8ymwGvXMCCimHXN0Dg8Ui62KOi03h0UgheoHWovJSCDF4CKre/xtFr3nL7lq/PKI",
+            "JsjVNz7/RK9FSXF6WwfONtLCyQGEuVAsB/KXfCBEyfKhaMwGHvhujRidGW5uV1no",
+            "lMGl3ODmo29Lgeu2uSE7EpJRZoe6hU6ddmBkqxax61ZtkaFlGFFpdo2K8balNNdz",
+            "ZsJ/9mmI9x3oOJ4/l1nhQbUO9ADbs7gJhFdV5Qkp30b5fCI7bU+aoe1ccBbLe/WM",
+            "YUty1PqcuQT7XjA+XmYuL261tvW8pBetT+i33/E2d8PzzYt2IuK9qeevyS+yxdwA",
+            "kfwejFWzzsUlJaDxs1x4XOxkMgSj+jo+g12dFOb7fyClsAnq23iDb8AuaT/BScAI",
+            "+lO+gher69+6LmM7VGHLG5k762J1jTaQCaKt1s8TAWV99Eo4491vL6fyvk3l/Cfg",
+            "RXSwiWFgj19Pn0Rq7CD9v22UE2vdUMBTcV4aw79mClk1YQ23jbF0y5DCjPdJ62Zo",
+            "tskBgFt3NoWV80jZ76zIBLrrjLwCCll8JjJtFwSkt2GX5RFBsVa4A8IDht9RtEk7",
+            "rrHgbSZQfkauEi/mH3/6CDZoLqSHudUZ7d4MaJwun1TkFYGe2ORwGJd4OBj3oGJp",
+            "H8YBwCpk///L/fKjX0Gg3M8nrpM4wrRFhPKidAgO/kcm25X4+ZHlVkWBTCt5RWKI",
+            "fHh6oLDZCqCfcgMkE1KKmwfIHaUkhq5BPRigwy6i5dh1DM4+1UCLh3dxzVbqE9b9",
+            "61NB19nXdRtDA2sOUnj9ve6m/wEPyCb6/zBQZqvCBYb1/AjdXpUrFT+DbpfyxaXN",
+            "XfhDVb5mNqNM/IVj0V5fvTc6vOfYbzQtPm10H+FdWWfb+rJRfyC3MA2w2IqstFe3",
+            "w3bu2iE6CQvSqRvge+ZqLKt/NqYwOURiUmpuklbl3kPJ97+mfKWoiqk8Iz1VY+bb",
+            "NMUC7aoGv+jcoj+WS6PYO8N6BeRVUUB3ZJSf8nzjgxm1/BcM+UD3BPrlhT11ODRs",
+            "baifGbprMWwt3dhb8cQgRT8GPdpO1OsDkzL6iikMjLHWWiA99GV6ruiHsIPw6boW",
+            "A6/uSOskbDHOROotKmddGTBd0iiHXAoQsJFt1ZjUkt6EHrgWs+GAvrvKpXs1mrz8",
+            "uj3GwEFrHS+Xuf2UDgpszYT3hI2cL/kUtGakVR7m7vVMZqXBUbZdGAEb1PZNPwsI",
+            "E4aMK02+EVB+tSN4Fzj99N2YD0inVYt+oPjr2tHhUS6aSGBNS/48Ki47DOg4Sxkn",
+            "lkOWnEbCD+XTnbDd",
+            "=agR5",
+            "-----END PGP MESSAGE-----",
+            "",
+            "",
+            "--YFrteb74qSXmggbOxZL9dRnhymywAi--",
+            "",
+            "",
+        ]
+    ).encode()
+    for i in range(100):
+        print("Sending mail", str(i))
+        try:
+            smtp.conn.sendmail(user, to_addr, mail)
+        except smtplib.SMTPSenderRefused as e:
+            if i == 0:
+                pytest.fail(f"rate limit was exceeded too early with msg {i} - maybe wait a minute before testing?")
+            if i < 41:
+                pytest.fail(f"rate limit was exceeded too early with msg {i}")
+            assert e.smtp_code == 450
+            assert b'4.7.1 Error: too much mail from' in e.smtp_error
+            return
+    pytest.fail("Rate limit was not exceeded")