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#!/usr/bin/env python
# Copyright (c) 2013 Yubico AB
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or
# without modification, are permitted provided that the following
# conditions are met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials provided
# with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
"""
Example web server providing single factor U2F enrollment and authentication.
It is intended to be run standalone in a single process, and stores user data
in memory only, with no permanent storage.
Enrollment will overwrite existing users.
If username is omitted, a default value of "user" will be used.
Any error will be returned as a stacktrace with a 400 response code.
Note that this is intended for test/demo purposes, not production use!
This example requires webob to be installed.
"""
from u2flib_server.u2f import (begin_registration, begin_authentication,
complete_registration, complete_authentication)
from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.serialization import Encoding
from webob.dec import wsgify
from webob import exc
import logging as log
import json
import traceback
import argparse
def get_origin(environ):
if environ.get('HTTP_HOST'):
host = environ['HTTP_HOST']
else:
host = environ['SERVER_NAME']
if environ['wsgi.url_scheme'] == 'https':
if environ['SERVER_PORT'] != '443':
host += ':' + environ['SERVER_PORT']
else:
if environ['SERVER_PORT'] != '80':
host += ':' + environ['SERVER_PORT']
return '%s://%s' % (environ['wsgi.url_scheme'], host)
class U2FServer(object):
"""
Very basic server providing a REST API to enroll one or more U2F device with
a user, and to perform authentication with the enrolled devices.
Only one challenge is valid at a time.
Four calls are provided: enroll, bind, sign and verify. Each of these
expects a username parameter, and bind and verify expect a
second parameter, data, containing the JSON formatted data which is output
by the U2F browser API upon calling the ENROLL or SIGN commands.
"""
def __init__(self):
self.users = {}
@wsgify
def __call__(self, request):
self.facet = get_origin(request.environ)
self.app_id = self.facet
page = request.path_info_pop()
if not page:
return json.dumps([self.facet])
try:
username = request.params.get('username', 'user')
data = request.params.get('data', None)
if page == 'enroll':
return self.enroll(username)
elif page == 'bind':
return self.bind(username, data)
elif page == 'sign':
return self.sign(username)
elif page == 'verify':
return self.verify(username, data)
else:
raise exc.HTTPNotFound()
except Exception:
log.exception("Exception in call to '%s'", page)
return exc.HTTPBadRequest(comment=traceback.format_exc())
def enroll(self, username):
if username not in self.users:
self.users[username] = {}
user = self.users[username]
enroll = begin_registration(self.app_id, user.get('_u2f_devices_', []))
user['_u2f_enroll_'] = enroll.json
return json.dumps(enroll.data_for_client)
def bind(self, username, data):
user = self.users[username]
enroll = user.pop('_u2f_enroll_')
device, cert = complete_registration(enroll, data, [self.facet])
user.setdefault('_u2f_devices_', []).append(device.json)
log.info("U2F device enrolled. Username: %s", username)
cert = x509.load_der_x509_certificate(cert, default_backend())
log.debug("Attestation certificate:\n%s",
cert.public_bytes(Encoding.PEM))
return json.dumps(True)
def sign(self, username):
user = self.users[username]
challenge = begin_authentication(
self.app_id, user.get('_u2f_devices_', []))
user['_u2f_challenge_'] = challenge.json
return json.dumps(challenge.data_for_client)
def verify(self, username, data):
user = self.users[username]
challenge = user.pop('_u2f_challenge_')
device, c, t = complete_authentication(challenge, data, [self.facet])
return json.dumps({
'keyHandle': device['keyHandle'],
'touch': t,
'counter': c
})
application = U2FServer()
if __name__ == '__main__':
from wsgiref.simple_server import make_server
parser = argparse.ArgumentParser(
description='U2F test server',
add_help=True,
formatter_class=argparse.ArgumentDefaultsHelpFormatter
)
parser.add_argument('-i', '--interface', nargs='?', default='localhost',
help='network interface to bind to')
parser.add_argument('-p', '--port', nargs='?', type=int, default=8081,
help='TCP port to bind to')
args = parser.parse_args()
log.basicConfig(level=log.DEBUG, format='%(asctime)s %(message)s',
datefmt='[%d/%b/%Y %H:%M:%S]')
log.info("Starting server on http://%s:%d", args.interface, args.port)
httpd = make_server(args.interface, args.port, application)
httpd.serve_forever()
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