# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
#
# 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 logging
import os
import warnings
from datetime import datetime
from hashlib import sha256
from typing import List
import six
from unpaddedbase64 import encode_base64
from OpenSSL import SSL, crypto
from twisted.internet._sslverify import Certificate, trustRootFromCertificates
from synapse.config._base import Config, ConfigError
from synapse.util import glob_to_regex
logger = logging.getLogger(__name__)
class TlsConfig(Config):
section = "tls"
def read_config(self, config: dict, config_dir_path: str, **kwargs):
acme_config = config.get("acme", None)
if acme_config is None:
acme_config = {}
self.acme_enabled = acme_config.get("enabled", False)
# hyperlink complains on py2 if this is not a Unicode
self.acme_url = six.text_type(
acme_config.get("url", "https://acme-v01.api.letsencrypt.org/directory")
)
self.acme_port = acme_config.get("port", 80)
self.acme_bind_addresses = acme_config.get("bind_addresses", ["::", "0.0.0.0"])
self.acme_reprovision_threshold = acme_config.get("reprovision_threshold", 30)
self.acme_domain = acme_config.get("domain", config.get("server_name"))
self.acme_account_key_file = self.abspath(
acme_config.get("account_key_file", config_dir_path + "/client.key")
)
self.tls_certificate_file = self.abspath(config.get("tls_certificate_path"))
self.tls_private_key_file = self.abspath(config.get("tls_private_key_path"))
if self.root.server.has_tls_listener():
if not self.tls_certificate_file:
raise ConfigError(
"tls_certificate_path must be specified if TLS-enabled listeners are "
"configured."
)
if not self.tls_private_key_file:
raise ConfigError(
"tls_private_key_path must be specified if TLS-enabled listeners are "
"configured."
)
self._original_tls_fingerprints = config.get("tls_fingerprints", [])
if self._original_tls_fingerprints is None:
self._original_tls_fingerprints = []
self.tls_fingerprints = list(self._original_tls_fingerprints)
# Whether to verify certificates on outbound federation traffic
self.federation_verify_certificates = config.get(
"federation_verify_certificates", True
)
# Minimum TLS version to use for outbound federation traffic
self.federation_client_minimum_tls_version = str(
config.get("federation_client_minimum_tls_version", 1)
)
if self.federation_client_minimum_tls_version not in ["1", "1.1", "1.2", "1.3"]:
raise ConfigError(
"federation_client_minimum_tls_version must be one of: 1, 1.1, 1.2, 1.3"
)
# Prevent people shooting themselves in the foot here by setting it to
# the biggest number blindly
if self.federation_client_minimum_tls_version == "1.3":
if getattr(SSL, "OP_NO_TLSv1_3", None) is None:
raise ConfigError(
(
"federation_client_minimum_tls_version cannot be 1.3, "
"your OpenSSL does not support it"
)
)
# Whitelist of domains to not verify certificates for
fed_whitelist_entries = config.get(
"federation_certificate_verification_whitelist", []
)
if fed_whitelist_entries is None:
fed_whitelist_entries = []
# Support globs (*) in whitelist values
self.federation_certificate_verification_whitelist = [] # type: List[str]
for entry in fed_whitelist_entries:
try:
entry_regex = glob_to_regex(entry.encode("ascii").decode("ascii"))
except UnicodeEncodeError:
raise ConfigError(
"IDNA domain names are not allowed in the "
"federation_certificate_verification_whitelist: %s" % (entry,)
)
# Convert globs to regex
self.federation_certificate_verification_whitelist.append(entry_regex)
# List of custom certificate authorities for federation traffic validation
custom_ca_list = config.get("federation_custom_ca_list", None)
# Read in and parse custom CA certificates
self.federation_ca_trust_root = None
if custom_ca_list is not None:
if len(custom_ca_list) == 0:
# A trustroot cannot be generated without any CA certificates.
# Raise an error if this option has been specified without any
# corresponding certificates.
raise ConfigError(
"federation_custom_ca_list specified without "
"any certificate files"
)
certs = []
for ca_file in custom_ca_list:
logger.debug("Reading custom CA certificate file: %s", ca_file)
content = self.read_file(ca_file, "federation_custom_ca_list")
# Parse the CA certificates
try:
cert_base = Certificate.loadPEM(content)
certs.append(cert_base)
except Exception as e:
raise ConfigError(
"Error parsing custom CA certificate file %s: %s" % (ca_file, e)
)
self.federation_ca_trust_root = trustRootFromCertificates(certs)
# This config option applies to non-federation HTTP clients
# (e.g. for talking to recaptcha, identity servers, and such)
# It should never be used in production, and is intended for
# use only when running tests.
self.use_insecure_ssl_client_just_for_testing_do_not_use = config.get(
"use_insecure_ssl_client_just_for_testing_do_not_use"
)
self.tls_certificate = None
self.tls_private_key = None
def is_disk_cert_valid(self, allow_self_signed=True):
"""
Is the certificate we have on disk valid, and if so, for how long?
Args:
allow_self_signed (bool): Should we allow the certificate we
read to be self signed?
Returns:
int: Days remaining of certificate validity.
None: No certificate exists.
"""
if not os.path.exists(self.tls_certificate_file):
return None
try:
with open(self.tls_certificate_file, "rb") as f:
cert_pem = f.read()
except Exception as e:
raise ConfigError(
"Failed to read existing certificate file %s: %s"
% (self.tls_certificate_file, e)
)
try:
tls_certificate = crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)
except Exception as e:
raise ConfigError(
"Failed to parse existing certificate file %s: %s"
% (self.tls_certificate_file, e)
)
if not allow_self_signed:
if tls_certificate.get_subject() == tls_certificate.get_issuer():
raise ValueError(
"TLS Certificate is self signed, and this is not permitted"
)
# YYYYMMDDhhmmssZ -- in UTC
expires_on = datetime.strptime(
tls_certificate.get_notAfter().decode("ascii"), "%Y%m%d%H%M%SZ"
)
now = datetime.utcnow()
days_remaining = (expires_on - now).days
return days_remaining
def read_certificate_from_disk(self, require_cert_and_key):
"""
Read the certificates and private key from disk.
Args:
require_cert_and_key (bool): set to True to throw an error if the certificate
and key file are not given
"""
if require_cert_and_key:
self.tls_private_key = self.read_tls_private_key()
self.tls_certificate = self.read_tls_certificate()
elif self.tls_certificate_file:
# we only need the certificate for the tls_fingerprints. Reload it if we
# can, but it's not a fatal error if we can't.
try:
self.tls_certificate = self.read_tls_certificate()
except Exception as e:
logger.info(
"Unable to read TLS certificate (%s). Ignoring as no "
"tls listeners enabled.",
e,
)
self.tls_fingerprints = list(self._original_tls_fingerprints)
if self.tls_certificate:
# Check that our own certificate is included in the list of fingerprints
# and include it if it is not.
x509_certificate_bytes = crypto.dump_certificate(
crypto.FILETYPE_ASN1, self.tls_certificate
)
sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
if sha256_fingerprint not in sha256_fingerprints:
self.tls_fingerprints.append({"sha256": sha256_fingerprint})
def generate_config_section(
self,
config_dir_path,
server_name,
data_dir_path,
tls_certificate_path,
tls_private_key_path,
acme_domain,
**kwargs
):
"""If the acme_domain is specified acme will be enabled.
If the TLS paths are not specified the default will be certs in the
config directory"""
base_key_name = os.path.join(config_dir_path, server_name)
if bool(tls_certificate_path) != bool(tls_private_key_path):
raise ConfigError(
"Please specify both a cert path and a key path or neither."
)
tls_enabled = (
"" if tls_certificate_path and tls_private_key_path or acme_domain else "#"
)
if not tls_certificate_path:
tls_certificate_path = base_key_name + ".tls.crt"
if not tls_private_key_path:
tls_private_key_path = base_key_name + ".tls.key"
acme_enabled = bool(acme_domain)
acme_domain = "matrix.example.com"
default_acme_account_file = os.path.join(data_dir_path, "acme_account.key")
# this is to avoid the max line length. Sorrynotsorry
proxypassline = (
"ProxyPass /.well-known/acme-challenge "
"http://localhost:8009/.well-known/acme-challenge"
)
# flake8 doesn't recognise that variables are used in the below string
_ = tls_enabled, proxypassline, acme_enabled, default_acme_account_file
return (
"""\
## TLS ##
# PEM-encoded X509 certificate for TLS.
# This certificate, as of Synapse 1.0, will need to be a valid and verifiable
# certificate, signed by a recognised Certificate Authority.
#
# See 'ACME support' below to enable auto-provisioning this certificate via
# Let's Encrypt.
#
# If supplying your own, be sure to use a `.pem` file that includes the
# full certificate chain including any intermediate certificates (for
# instance, if using certbot, use `fullchain.pem` as your certificate,
# not `cert.pem`).
#
%(tls_enabled)stls_certificate_path: "%(tls_certificate_path)s"
# PEM-encoded private key for TLS
#
%(tls_enabled)stls_private_key_path: "%(tls_private_key_path)s"
# Whether to verify TLS server certificates for outbound federation requests.
#
# Defaults to `true`. To disable certificate verification, uncomment the
# following line.
#
#federation_verify_certificates: false
# The minimum TLS version that will be used for outbound federation requests.
#
# Defaults to `1`. Configurable to `1`, `1.1`, `1.2`, or `1.3`. Note
# that setting this value higher than `1.2` will prevent federation to most
# of the public Matrix network: only configure it to `1.3` if you have an
# entirely private federation setup and you can ensure TLS 1.3 support.
#
#federation_client_minimum_tls_version: 1.2
# Skip federation certificate verification on the following whitelist
# of domains.
#
# This setting should only be used in very specific cases, such as
# federation over Tor hidden services and similar. For private networks
# of homeservers, you likely want to use a private CA instead.
#
# Only effective if federation_verify_certicates is `true`.
#
#federation_certificate_verification_whitelist:
# - lon.example.com
# - *.domain.com
# - *.onion
# List of custom certificate authorities for federation traffic.
#
# This setting should only normally be used within a private network of
# homeservers.
#
# Note that this list will replace those that are provided by your
# operating environment. Certificates must be in PEM format.
#
#federation_custom_ca_list:
# - myCA1.pem
# - myCA2.pem
# - myCA3.pem
# ACME support: This will configure Synapse to request a valid TLS certificate
# for your configured `server_name` via Let's Encrypt.
#
# Note that provisioning a certificate in this way requires port 80 to be
# routed to Synapse so that it can complete the http-01 ACME challenge.
# By default, if you enable ACME support, Synapse will attempt to listen on
# port 80 for incoming http-01 challenges - however, this will likely fail
# with 'Permission denied' or a similar error.
#
# There are a couple of potential solutions to this:
#
# * If you already have an Apache, Nginx, or similar listening on port 80,
# you can configure Synapse to use an alternate port, and have your web
# server forward the requests. For example, assuming you set 'port: 8009'
# below, on Apache, you would write:
#
# %(proxypassline)s
#
# * Alternatively, you can use something like `authbind` to give Synapse
# permission to listen on port 80.
#
acme:
# ACME support is disabled by default. Set this to `true` and uncomment
# tls_certificate_path and tls_private_key_path above to enable it.
#
enabled: %(acme_enabled)s
# Endpoint to use to request certificates. If you only want to test,
# use Let's Encrypt's staging url:
# https://acme-staging.api.letsencrypt.org/directory
#
#url: https://acme-v01.api.letsencrypt.org/directory
# Port number to listen on for the HTTP-01 challenge. Change this if
# you are forwarding connections through Apache/Nginx/etc.
#
port: 80
# Local addresses to listen on for incoming connections.
# Again, you may want to change this if you are forwarding connections
# through Apache/Nginx/etc.
#
bind_addresses: ['::', '0.0.0.0']
# How many days remaining on a certificate before it is renewed.
#
reprovision_threshold: 30
# The domain that the certificate should be for. Normally this
# should be the same as your Matrix domain (i.e., 'server_name'), but,
# by putting a file at 'https://<server_name>/.well-known/matrix/server',
# you can delegate incoming traffic to another server. If you do that,
# you should give the target of the delegation here.
#
# For example: if your 'server_name' is 'example.com', but
# 'https://example.com/.well-known/matrix/server' delegates to
# 'matrix.example.com', you should put 'matrix.example.com' here.
#
# If not set, defaults to your 'server_name'.
#
domain: %(acme_domain)s
# file to use for the account key. This will be generated if it doesn't
# exist.
#
# If unspecified, we will use CONFDIR/client.key.
#
account_key_file: %(default_acme_account_file)s
# List of allowed TLS fingerprints for this server to publish along
# with the signing keys for this server. Other matrix servers that
# make HTTPS requests to this server will check that the TLS
# certificates returned by this server match one of the fingerprints.
#
# Synapse automatically adds the fingerprint of its own certificate
# to the list. So if federation traffic is handled directly by synapse
# then no modification to the list is required.
#
# If synapse is run behind a load balancer that handles the TLS then it
# will be necessary to add the fingerprints of the certificates used by
# the loadbalancers to this list if they are different to the one
# synapse is using.
#
# Homeservers are permitted to cache the list of TLS fingerprints
# returned in the key responses up to the "valid_until_ts" returned in
# key. It may be necessary to publish the fingerprints of a new
# certificate and wait until the "valid_until_ts" of the previous key
# responses have passed before deploying it.
#
# You can calculate a fingerprint from a given TLS listener via:
# openssl s_client -connect $host:$port < /dev/null 2> /dev/null |
# openssl x509 -outform DER | openssl sha256 -binary | base64 | tr -d '='
# or by checking matrix.org/federationtester/api/report?server_name=$host
#
#tls_fingerprints: [{"sha256": "<base64_encoded_sha256_fingerprint>"}]
"""
# Lowercase the string representation of boolean values
% {
x[0]: str(x[1]).lower() if isinstance(x[1], bool) else x[1]
for x in locals().items()
}
)
def read_tls_certificate(self):
"""Reads the TLS certificate from the configured file, and returns it
Also checks if it is self-signed, and warns if so
Returns:
OpenSSL.crypto.X509: the certificate
"""
cert_path = self.tls_certificate_file
logger.info("Loading TLS certificate from %s", cert_path)
cert_pem = self.read_file(cert_path, "tls_certificate_path")
cert = crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)
# Check if it is self-signed, and issue a warning if so.
if cert.get_issuer() == cert.get_subject():
warnings.warn(
(
"Self-signed TLS certificates will not be accepted by Synapse 1.0. "
"Please either provide a valid certificate, or use Synapse's ACME "
"support to provision one."
)
)
return cert
def read_tls_private_key(self):
"""Reads the TLS private key from the configured file, and returns it
Returns:
OpenSSL.crypto.PKey: the private key
"""
private_key_path = self.tls_private_key_file
logger.info("Loading TLS key from %s", private_key_path)
private_key_pem = self.read_file(private_key_path, "tls_private_key_path")
return crypto.load_privatekey(crypto.FILETYPE_PEM, private_key_pem)