140 lines
4.6 KiB
Python
140 lines
4.6 KiB
Python
# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from zope.interface import implementer
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from OpenSSL import SSL, crypto
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from twisted.internet._sslverify import _defaultCurveName
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from twisted.internet.abstract import isIPAddress, isIPv6Address
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from twisted.internet.interfaces import IOpenSSLClientConnectionCreator
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from twisted.internet.ssl import CertificateOptions, ContextFactory
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from twisted.python.failure import Failure
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logger = logging.getLogger(__name__)
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class ServerContextFactory(ContextFactory):
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"""Factory for PyOpenSSL SSL contexts that are used to handle incoming
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connections."""
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def __init__(self, config):
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self._context = SSL.Context(SSL.SSLv23_METHOD)
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self.configure_context(self._context, config)
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@staticmethod
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def configure_context(context, config):
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try:
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_ecCurve = crypto.get_elliptic_curve(_defaultCurveName)
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context.set_tmp_ecdh(_ecCurve)
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except Exception:
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logger.exception("Failed to enable elliptic curve for TLS")
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context.set_options(SSL.OP_NO_SSLv2 | SSL.OP_NO_SSLv3)
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context.use_certificate_chain_file(config.tls_certificate_file)
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if not config.no_tls:
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context.use_privatekey(config.tls_private_key)
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# https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/
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context.set_cipher_list(
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"ECDH+AESGCM:ECDH+CHACHA20:ECDH+AES256:ECDH+AES128:!aNULL:!SHA1"
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)
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def getContext(self):
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return self._context
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def _idnaBytes(text):
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"""
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Convert some text typed by a human into some ASCII bytes. This is a
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copy of twisted.internet._idna._idnaBytes. For documentation, see the
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twisted documentation.
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"""
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try:
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import idna
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except ImportError:
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return text.encode("idna")
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else:
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return idna.encode(text)
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def _tolerateErrors(wrapped):
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"""
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Wrap up an info_callback for pyOpenSSL so that if something goes wrong
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the error is immediately logged and the connection is dropped if possible.
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This is a copy of twisted.internet._sslverify._tolerateErrors. For
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documentation, see the twisted documentation.
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"""
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def infoCallback(connection, where, ret):
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try:
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return wrapped(connection, where, ret)
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except: # noqa: E722, taken from the twisted implementation
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f = Failure()
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logger.exception("Error during info_callback")
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connection.get_app_data().failVerification(f)
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return infoCallback
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@implementer(IOpenSSLClientConnectionCreator)
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class ClientTLSOptions(object):
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"""
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Client creator for TLS without certificate identity verification. This is a
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copy of twisted.internet._sslverify.ClientTLSOptions with the identity
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verification left out. For documentation, see the twisted documentation.
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"""
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def __init__(self, hostname, ctx):
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self._ctx = ctx
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if isIPAddress(hostname) or isIPv6Address(hostname):
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self._hostnameBytes = hostname.encode('ascii')
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self._sendSNI = False
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else:
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self._hostnameBytes = _idnaBytes(hostname)
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self._sendSNI = True
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ctx.set_info_callback(
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_tolerateErrors(self._identityVerifyingInfoCallback)
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)
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def clientConnectionForTLS(self, tlsProtocol):
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context = self._ctx
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connection = SSL.Connection(context, None)
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connection.set_app_data(tlsProtocol)
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return connection
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def _identityVerifyingInfoCallback(self, connection, where, ret):
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# Literal IPv4 and IPv6 addresses are not permitted
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# as host names according to the RFCs
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if where & SSL.SSL_CB_HANDSHAKE_START and self._sendSNI:
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connection.set_tlsext_host_name(self._hostnameBytes)
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class ClientTLSOptionsFactory(object):
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"""Factory for Twisted ClientTLSOptions that are used to make connections
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to remote servers for federation."""
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def __init__(self, config):
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# We don't use config options yet
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pass
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def get_options(self, host):
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return ClientTLSOptions(
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host,
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CertificateOptions(verify=False).getContext()
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)
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