# 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
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# POSSIBILITY OF SUCH DAMAGE.
from __future__ import annotations
from .base import (
Attestation,
AttestationType,
AttestationResult,
InvalidSignature,
catch_builtins,
)
from ..cose import ES256
from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.exceptions import InvalidSignature as _InvalidSignature
[docs]
class FidoU2FAttestation(Attestation):
FORMAT = "fido-u2f"
[docs]
@catch_builtins
def verify(self, statement, auth_data, client_data_hash):
cd = auth_data.credential_data
pk = b"\x04" + cd.public_key[-2] + cd.public_key[-3]
x5c = statement["x5c"]
FidoU2FAttestation.verify_signature(
auth_data.rp_id_hash,
client_data_hash,
cd.credential_id,
pk,
x5c[0],
statement["sig"],
)
return AttestationResult(AttestationType.BASIC, x5c)
[docs]
@staticmethod
def verify_signature(
app_param, client_param, key_handle, public_key, cert_bytes, signature
):
m = b"\0" + app_param + client_param + key_handle + public_key
cert = x509.load_der_x509_certificate(cert_bytes, default_backend())
try:
ES256.from_cryptography_key(cert.public_key()).verify(m, signature)
except _InvalidSignature:
raise InvalidSignature()