forked-synapse/synapse/handlers/send_email.py
Richard van der Hoff 74d7336686
Add a setting to disable TLS for sending email (#10546)
This is mostly useful in case the server offers TLS, but doesn't present a valid certificate.
2021-08-06 10:13:34 +00:00

159 lines
5.2 KiB
Python

# Copyright 2021 The Matrix.org C.I.C. Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import email.utils
import logging
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from io import BytesIO
from typing import TYPE_CHECKING, Optional
from twisted.internet.defer import Deferred
from twisted.internet.interfaces import IReactorTCP
from twisted.mail.smtp import ESMTPSenderFactory
from synapse.logging.context import make_deferred_yieldable
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
async def _sendmail(
reactor: IReactorTCP,
smtphost: str,
smtpport: int,
from_addr: str,
to_addr: str,
msg_bytes: bytes,
username: Optional[bytes] = None,
password: Optional[bytes] = None,
require_auth: bool = False,
require_tls: bool = False,
tls_hostname: Optional[str] = None,
) -> None:
"""A simple wrapper around ESMTPSenderFactory, to allow substitution in tests
Params:
reactor: reactor to use to make the outbound connection
smtphost: hostname to connect to
smtpport: port to connect to
from_addr: "From" address for email
to_addr: "To" address for email
msg_bytes: Message content
username: username to authenticate with, if auth is enabled
password: password to give when authenticating
require_auth: if auth is not offered, fail the request
require_tls: if TLS is not offered, fail the reqest
tls_hostname: TLS hostname to check for. None to disable TLS.
"""
msg = BytesIO(msg_bytes)
d: "Deferred[object]" = Deferred()
factory = ESMTPSenderFactory(
username,
password,
from_addr,
to_addr,
msg,
d,
heloFallback=True,
requireAuthentication=require_auth,
requireTransportSecurity=require_tls,
hostname=tls_hostname,
)
# the IReactorTCP interface claims host has to be a bytes, which seems to be wrong
reactor.connectTCP(smtphost, smtpport, factory, timeout=30, bindAddress=None) # type: ignore[arg-type]
await make_deferred_yieldable(d)
class SendEmailHandler:
def __init__(self, hs: "HomeServer"):
self.hs = hs
self._reactor = hs.get_reactor()
self._from = hs.config.email.email_notif_from
self._smtp_host = hs.config.email.email_smtp_host
self._smtp_port = hs.config.email.email_smtp_port
user = hs.config.email.email_smtp_user
self._smtp_user = user.encode("utf-8") if user is not None else None
passwd = hs.config.email.email_smtp_pass
self._smtp_pass = passwd.encode("utf-8") if passwd is not None else None
self._require_transport_security = hs.config.email.require_transport_security
self._enable_tls = hs.config.email.enable_smtp_tls
self._sendmail = _sendmail
async def send_email(
self,
email_address: str,
subject: str,
app_name: str,
html: str,
text: str,
) -> None:
"""Send a multipart email with the given information.
Args:
email_address: The address to send the email to.
subject: The email's subject.
app_name: The app name to include in the From header.
html: The HTML content to include in the email.
text: The plain text content to include in the email.
"""
try:
from_string = self._from % {"app": app_name}
except (KeyError, TypeError):
from_string = self._from
raw_from = email.utils.parseaddr(from_string)[1]
raw_to = email.utils.parseaddr(email_address)[1]
if raw_to == "":
raise RuntimeError("Invalid 'to' address")
html_part = MIMEText(html, "html", "utf8")
text_part = MIMEText(text, "plain", "utf8")
multipart_msg = MIMEMultipart("alternative")
multipart_msg["Subject"] = subject
multipart_msg["From"] = from_string
multipart_msg["To"] = email_address
multipart_msg["Date"] = email.utils.formatdate()
multipart_msg["Message-ID"] = email.utils.make_msgid()
multipart_msg.attach(text_part)
multipart_msg.attach(html_part)
logger.info("Sending email to %s" % email_address)
await self._sendmail(
self._reactor,
self._smtp_host,
self._smtp_port,
raw_from,
raw_to,
multipart_msg.as_string().encode("utf8"),
username=self._smtp_user,
password=self._smtp_pass,
require_auth=self._smtp_user is not None,
require_tls=self._require_transport_security,
tls_hostname=self._smtp_host if self._enable_tls else None,
)