CNSA-276-FP/credblobex.py

# Copyright (c) 2018 Yubico AB
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#   without modification, are permitted provided that the following
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"""
Connects to the first FIDO device found (starts from USB, then looks into NFC),
creates a new credential for it, and authenticates the credential.
This works with both FIDO 2.0 devices as well as with U2F devices.
On Windows, the native WebAuthn API will be used.
"""
from fido2.hid import CtapHidDevice
from fido2.client import Fido2Client, WindowsClient, UserInteraction
from fido2.server import Fido2Server
from getpass import getpass
import sys
import ctypes

try:
    from fido2.pcsc import CtapPcscDevice
except ImportError:
    CtapPcscDevice = None


def enumerate_devices():
    for dev in CtapHidDevice.list_devices():
        yield dev
    if CtapPcscDevice:
        for dev in CtapPcscDevice.list_devices():
            yield dev


# Handle user interaction
class CliInteraction(UserInteraction):
    def prompt_up(self):
        print("\nTouch your authenticator device now...\n")

    def request_pin(self, permissions, rd_id):
        return getpass("Enter PIN: ")

    def request_uv(self, permissions, rd_id):
        print("User Verification required.")
        return True


uv = "discouraged"

if WindowsClient.is_available() and not ctypes.windll.shell32.IsUserAnAdmin():
    # Use the Windows WebAuthn API if available, and we're not running as admin
    client = WindowsClient("https://example.com")
else:
    # Locate a device
    for dev in enumerate_devices():
        client = Fido2Client(
            dev, "https://example.com", user_interaction=CliInteraction()
        )
        if client.info.options.get("rk"):
            break
    else:
        print("No Authenticator with support for resident key found!")
        sys.exit(1)

    # Prefer UV if supported
    if client.info.options.get("uv"):
        uv = "preferred"
        print("Authenticator supports User Verification")


server = Fido2Server({"id": "example.com", "name": "Example RP"}, attestation="direct")

user = {"id": b"user_id", "name": "A. User"}

# Prepare parameters for makeCredential
create_options, state = server.register_begin(
    user,
    resident_key_requirement="required",
    user_verification=uv,
    authenticator_attachment="cross-platform",
)

# Create a credential
result = client.make_credential(create_options["publicKey"])


# Complete registration
auth_data = server.register_complete(
    state, result.client_data, result.attestation_object
)
credentials = [auth_data.credential_data]

print("New credential created!")

print("CLIENT DATA:", result.client_data)
print("ATTESTATION OBJECT:", result.attestation_object)
print()
print("CREDENTIAL DATA:", auth_data.credential_data)


# Prepare parameters for getAssertion
request_options, state = server.authenticate_begin(user_verification=uv)

# Authenticate the credential
selection = client.get_assertion(request_options["publicKey"])
result = selection.get_response(0)  # There may be multiple responses, get the first.

print("USER ID:", result.user_handle)

# Complete authenticator
server.authenticate_complete(
    state,
    credentials,
    result.credential_id,
    result.client_data,
    result.authenticator_data,
    result.signature,
)

print("Credential authenticated!")

print("CLIENT DATA:", result.client_data)
print()
print("AUTHENTICATOR DATA:", result.authenticator_data)