118 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
# -*- coding: utf-8 -*-
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# Copyright 2019 New Vector Ltd
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# Copyright 2019 The Matrix.org Foundation C.I.C.
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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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"""
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Utility function to create an ACME issuing service.
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This file contains the unconditional imports on the acme and cryptography bits that we
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only need (and may only have available) if we are doing ACME, so is designed to be
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imported conditionally.
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"""
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import logging
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import attr
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives import serialization
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from josepy import JWKRSA
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from josepy.jwa import RS256
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from txacme.challenges import HTTP01Responder
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from txacme.client import Client
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from txacme.interfaces import ICertificateStore
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from txacme.service import AcmeIssuingService
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from txacme.util import generate_private_key
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from zope.interface import implementer
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from twisted.internet import defer
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from twisted.python.filepath import FilePath
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from twisted.python.url import URL
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logger = logging.getLogger(__name__)
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def create_issuing_service(reactor, acme_url, account_key_file, well_known_resource):
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    """Create an ACME issuing service, and attach it to a web Resource
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    Args:
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        reactor: twisted reactor
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        acme_url (str): URL to use to request certificates
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        account_key_file (str): where to store the account key
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        well_known_resource (twisted.web.IResource): web resource for .well-known.
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            we will attach a child resource for "acme-challenge".
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    Returns:
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        AcmeIssuingService
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    """
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    responder = HTTP01Responder()
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    well_known_resource.putChild(b"acme-challenge", responder.resource)
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    store = ErsatzStore()
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    return AcmeIssuingService(
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        cert_store=store,
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        client_creator=(
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            lambda: Client.from_url(
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                reactor=reactor,
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                url=URL.from_text(acme_url),
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                key=load_or_create_client_key(account_key_file),
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                alg=RS256,
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            )
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        ),
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        clock=reactor,
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        responders=[responder],
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    )
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@attr.s(slots=True)
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@implementer(ICertificateStore)
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class ErsatzStore:
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    """
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    A store that only stores in memory.
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    """
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    certs = attr.ib(default=attr.Factory(dict))
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    def store(self, server_name, pem_objects):
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        self.certs[server_name] = [o.as_bytes() for o in pem_objects]
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        return defer.succeed(None)
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def load_or_create_client_key(key_file):
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    """Load the ACME account key from a file, creating it if it does not exist.
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    Args:
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        key_file (str): name of the file to use as the account key
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    """
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    # this is based on txacme.endpoint.load_or_create_client_key, but doesn't
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    # hardcode the 'client.key' filename
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    acme_key_file = FilePath(key_file)
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    if acme_key_file.exists():
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        logger.info("Loading ACME account key from '%s'", acme_key_file)
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        key = serialization.load_pem_private_key(
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            acme_key_file.getContent(), password=None, backend=default_backend()
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        )
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    else:
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        logger.info("Saving new ACME account key to '%s'", acme_key_file)
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        key = generate_private_key("rsa")
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        acme_key_file.setContent(
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            key.private_bytes(
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                encoding=serialization.Encoding.PEM,
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                format=serialization.PrivateFormat.TraditionalOpenSSL,
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                encryption_algorithm=serialization.NoEncryption(),
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            )
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        )
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    return JWKRSA(key=key)
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