mirror of https://github.com/Yubico/python-fido2
150 lines
5.2 KiB
Python
150 lines
5.2 KiB
Python
# Copyright 2016 Google Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Testing utilties for pyu2f.
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Testing utilities such as a fake implementation of the pyhidapi device object
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that implements parts of the U2FHID frame protocol. This makes it easy to tests
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of higher level abstractions without having to use mock to mock out low level
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framing details.
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"""
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from fido_host.pyu2f import base, hidtransport
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class UnsupportedCommandError(Exception):
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pass
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class FakeHidDevice(base.HidDevice):
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"""Implements a fake hiddevice per the pyhidapi interface.
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This class implemetns a fake hiddevice that can be patched into
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code that uses pyhidapi to communicate with a hiddevice. This device
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impelents part of U2FHID protocol and can be used to test interactions
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with a security key. It supports arbitrary MSG replies as well as
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channel allocation, and ping.
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"""
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def __init__(self, cid_to_allocate, msg_reply=None):
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self.cid_to_allocate = cid_to_allocate
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self.msg_reply = msg_reply
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self.transaction_active = False
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self.full_packet_received = False
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self.init_packet = None
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self.packet_body = None
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self.reply = None
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self.seq = 0
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self.received_packets = []
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self.busy_count = 0
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def GetInReportDataLength(self):
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return 64
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def GetOutReportDataLength(self):
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return 64
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def Write(self, data):
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"""Write to the device.
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Writes to the fake hid device. This function is stateful: if a transaction
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is currently open with the client, it will continue to accumulate data
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for the client->device messages until the expected size is reached.
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Args:
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data: A list of integers to accept as data payload. It should be 64 bytes
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in length: just the report data--NO report ID.
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"""
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if len(data) < 64:
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data = bytearray(data) + bytearray(0 for i in range(0, 64 - len(data)))
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if not self.transaction_active:
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self.transaction_active = True
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self.init_packet = hidtransport.UsbHidTransport.InitPacket.FromWireFormat(
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64, data)
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self.packet_body = self.init_packet.payload
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self.full_packet_received = False
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self.received_packets.append(self.init_packet)
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else:
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cont_packet = hidtransport.UsbHidTransport.ContPacket.FromWireFormat(
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64, data)
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self.packet_body += cont_packet.payload
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self.received_packets.append(cont_packet)
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if len(self.packet_body) >= self.init_packet.size:
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self.packet_body = self.packet_body[0:self.init_packet.size]
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self.full_packet_received = True
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def Read(self):
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"""Read from the device.
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Reads from the fake hid device. This function only works if a transaction
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is open and a complete write has taken place. If so, it will return the
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next reply packet. It should be called repeatedly until all expected
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data has been received. It always reads one report.
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Returns:
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A list of ints containing the next packet.
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Raises:
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UnsupportedCommandError: if the requested amount is not 64.
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"""
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if not self.transaction_active or not self.full_packet_received:
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return None
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ret = None
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if self.busy_count > 0:
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ret = hidtransport.UsbHidTransport.InitPacket(
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64, self.init_packet.cid, hidtransport.UsbHidTransport.U2FHID_ERROR,
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1, hidtransport.UsbHidTransport.ERR_CHANNEL_BUSY)
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self.busy_count -= 1
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elif self.reply: # reply in progress
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next_frame = self.reply[0:59]
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self.reply = self.reply[59:]
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ret = hidtransport.UsbHidTransport.ContPacket(64, self.init_packet.cid,
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self.seq, next_frame)
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self.seq += 1
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else:
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self.InternalGenerateReply()
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first_frame = self.reply[0:57]
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ret = hidtransport.UsbHidTransport.InitPacket(
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64, self.init_packet.cid, self.init_packet.cmd, len(self.reply),
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first_frame)
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self.reply = self.reply[57:]
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if not self.reply: # done after this packet
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self.reply = None
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self.transaction_active = False
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self.seq = 0
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return ret.ToWireFormat()
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def SetChannelBusyCount(self, busy_count): # pylint: disable=invalid-name
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"""Mark the channel busy for next busy_count read calls."""
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self.busy_count = busy_count
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def InternalGenerateReply(self): # pylint: disable=invalid-name
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if self.init_packet.cmd == hidtransport.UsbHidTransport.U2FHID_INIT:
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nonce = self.init_packet.payload[0:8]
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self.reply = nonce + self.cid_to_allocate + bytearray(
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b'\x01\x00\x00\x00\x00')
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elif self.init_packet.cmd == hidtransport.UsbHidTransport.U2FHID_PING:
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self.reply = self.init_packet.payload
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elif self.init_packet.cmd == hidtransport.UsbHidTransport.U2FHID_MSG:
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self.reply = self.msg_reply
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else:
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raise UnsupportedCommandError()
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