# Copyright (c) 2020 Yubico AB
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#
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# without modification, are permitted provided that the following
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#
# 1. Redistributions of source code must retain the above copyright
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# 2. Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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import logging
import struct
from threading import Event
from typing import Callable, Iterator
from fido2.ctap import STATUS, CtapDevice, CtapError
from fido2.hid import CAPABILITY, CTAPHID
from yubikit.core import Version
from yubikit.core.smartcard import (
AID,
ApduError,
SmartCardConnection,
SmartCardProtocol,
)
from yubikit.core.smartcard.scp import ScpKeyParams
from . import USB_INTERFACE, Connection
logger = logging.getLogger(__name__)
# Make CtapDevice a Connection
FidoConnection = CtapDevice
FidoConnection.usb_interface = USB_INTERFACE.FIDO # type: ignore[attr-defined]
Connection.register(FidoConnection)
# Use SmartCardConnection for FIDO access, allowing usage of SCP
[docs]
class SmartCardCtapDevice(CtapDevice, Connection):
usb_interface = USB_INTERFACE.CCID
def __init__(
self,
connection: SmartCardConnection,
scp_key_params: ScpKeyParams | None = None,
):
self._capabilities = CAPABILITY(0)
self.protocol = SmartCardProtocol(connection)
resp = self.protocol.select(AID.FIDO)
if resp == b"U2F_V2":
self._capabilities |= CAPABILITY.NMSG
if scp_key_params:
# We can at least raise the configuration level to 5.3.0,
# since SCP is not available before then
self.protocol.configure(Version(5, 3, 0))
self.protocol.init_scp(scp_key_params)
try: # Probe for CTAP2 by calling GET_INFO
self.call(CTAPHID.CBOR, b"\x04")
self._capabilities |= CAPABILITY.CBOR
except CtapError:
if not self._capabilities:
raise ValueError("Unsupported device")
logger.debug("FIDO session initialized")
@property
def capabilities(self) -> CAPABILITY:
return self._capabilities
[docs]
def close(self) -> None:
self.protocol.close()
[docs]
def call(
self,
cmd: int,
data: bytes = b"",
event: Event | None = None,
on_keepalive: Callable[[STATUS], None] | None = None,
) -> bytes:
match cmd:
case CTAPHID.MSG:
cla, ins, p1, p2 = data[:4]
if data[4] == 0:
ln = struct.unpack(">H", data[5:7])[0]
data = data[7 : 7 + ln]
else:
data = data[5 : 5 + data[4]]
case CTAPHID.CBOR:
# NFCCTAP_MSG
cla, ins, p1, p2 = 0x80, 0x10, 0x80, 0x00
case _:
raise CtapError(CtapError.ERR.INVALID_COMMAND)
event = event or Event()
last_ka = None
try:
while True:
try:
return self.protocol.send_apdu(cla, ins, p1, p2, data)
except ApduError as e:
if e.sw == 0x9100:
ins, p1 = 0x11, 0x00 # NFCCTAP_GETRESPONSE
ka_status = STATUS(e.data[0])
if on_keepalive and last_ka != ka_status:
last_ka = ka_status
on_keepalive(ka_status)
if event.wait(0.1):
p1 = 0x11 # cancel
continue
raise CtapError(CtapError.ERR.OTHER) # TODO: Map from SW error
except KeyboardInterrupt:
if ins == 0x11:
logger.debug("Keyboard interrupt, cancelling...")
self.protocol.send_apdu(cla, ins, 0x11, p2)
raise
[docs]
@classmethod
def list_devices(cls) -> Iterator[CtapDevice]:
return iter([]) # Not implemented