Files
python-fido2/examples/server/server.py
2018-04-06 16:45:48 +02:00

231 lines
6.9 KiB
Python

# Copyright (c) 2018 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 demo server to use a supported web browser to call the WebAuthn APIs
to register and use a credential.
To run (using a virtualenv is recommended):
$ pip install -r requirements.txt
$ python server.py
Now navigate to https://localhost:5000 in a supported web browser.
"""
from __future__ import print_function, absolute_import, unicode_literals
from fido2.client import ClientData
from fido2.ctap2 import AttestationObject, AuthenticatorData
from flask import Flask, request
import os
HTML = """
<html>
<head><title>Fido 2.0 webauthn demo</title></head>
<body>
<h1>Webauthn demo</h1>
<p>
<strong>This demo requires a browser supporting the WebAuthn API!</strong>
</p>
<hr>
{content}
</body>
</html>
"""
INDEX_HTML = HTML.format(content="""
<a href="/register">Register</a><br>
<a href="/authenticate">Authenticate</a><br>
""")
REGISTER_HTML = HTML.format(content="""
<h2>Register a credential</h2>
<p>Touch your authenticator device now...</p>
<script>
navigator.credentials.create({{
publicKey: {{
rp: {{
id: document.domain,
name: 'Demo server'
}},
user: {{
id: {user_id},
name: 'a_user',
displayName: 'A. User',
icon: 'https://example.com/image.png'
}},
challenge: {challenge},
pubKeyCredParams: [
{{
alg: -7,
type: 'public-key'
}}
],
excludeCredentials: [],
attestation: 'direct',
timeout: 60000
}}
}}).then(function(attestation) {{
console.log(attestation);
console.log(JSON.stringify({{
attestationObject: Array.from(new Uint8Array(attestation.response.attestationObject)),
clientData: Array.from(new Uint8Array(attestation.response.clientDataJSON))
}}));
fetch('/register', {{
method: 'POST',
body: JSON.stringify({{
attestationObject: Array.from(new Uint8Array(attestation.response.attestationObject)),
clientData: Array.from(new Uint8Array(attestation.response.clientDataJSON))
}})
}}).then(function() {{
alert('Registration successful. More details in server log...');
window.location = '/';
}});
}}, function(reason) {{
console.log('Failed', reason);
}});
</script>
""") # noqa
AUTH_HTML = HTML.format(content="""
<h2>Authenticate using a credential</h2>
<p>Touch your authenticator device now...</p>
<script>
navigator.credentials.get({{
publicKey: {{
rpId: document.domain,
challenge: {challenge},
allowCredentials: [
{{
type: 'public-key',
id: {credential_id}
}}
],
timeout: 60000
}}
}}).then(function(attestation) {{
console.log(attestation);
fetch('/authenticate', {{
method: 'POST',
body: JSON.stringify({{
authenticatorData: Array.from(new Uint8Array(attestation.response.authenticatorData)),
clientData: Array.from(new Uint8Array(attestation.response.clientDataJSON)),
signature: Array.from(new Uint8Array(attestation.response.signature))
}})
}}).then(function() {{
alert('Authentication successful. More details in server log...');
window.location = '/';
}});
}}, function(reason) {{
console.log('Failed', reason);
}});
</script>
""") # noqa
def to_js_array(value):
return 'new Uint8Array(%r)' % list(bytearray(value))
def from_js_array(value):
return bytes(bytearray(value))
app = Flask(__name__)
global credential, last_challenge
credential, last_challenge = None, None
@app.route('/')
def index():
return INDEX_HTML
@app.route('/register', methods=['GET', 'POST'])
def register():
global credential, last_challenge
if request.method == 'POST':
data = request.get_json(force=True)
client_data = ClientData(from_js_array(data['clientData']))
att_obj = AttestationObject(from_js_array(data['attestationObject']))
print('clientData', client_data)
print('AttestationObject:', att_obj)
# Verify the challenge
if client_data.challenge != last_challenge:
raise ValueError('Challenge mismatch!')
# Verify the signature
att_obj.verify(client_data.hash)
credential = att_obj.auth_data.credential_data
print('REGISTERED CREDENTIAL:', credential)
return 'OK'
last_challenge = os.urandom(32)
return REGISTER_HTML.format(
user_id=to_js_array(b'user_id'),
challenge=to_js_array(last_challenge)
)
@app.route('/authenticate', methods=['GET', 'POST'])
def authenticate():
global credential, last_challenge
if not credential:
return HTML.format(content='No credential registered!')
if request.method == 'POST':
data = request.get_json(force=True)
client_data = ClientData(from_js_array(data['clientData']))
auth_data = AuthenticatorData(from_js_array(data['authenticatorData']))
signature = from_js_array(data['signature'])
print('clientData', client_data)
print('AuthenticatorData', auth_data)
# Verify the challenge
if client_data.challenge != last_challenge:
raise ValueError('Challenge mismatch!')
# Verify the signature
credential.public_key.verify(auth_data + client_data.hash, signature)
print('ASSERTION OK')
return 'OK'
last_challenge = os.urandom(32)
return AUTH_HTML.format(
challenge=to_js_array(last_challenge),
credential_id=to_js_array(credential.credential_id)
)
if __name__ == '__main__':
print(__doc__)
app.run(ssl_context='adhoc', debug=True)