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|
#!/usr/bin/env python3
#
# SPDX-FileCopyrightText: © 2019 The usbmon-tools Authors
# SPDX-FileCopyrightText: © 2020 The glucometerutils Authors
#
# SPDX-License-Identifier: Apache-2.0
import argparse
import logging
import sys
import construct
import usbmon
import usbmon.pcapng
_SERIAL_NUMBER_RESPONSE_TYPE = 0x06
_ENCRYPTION_SETUP_REQ_TYPE = 0x14
_ENCRYPTION_SETUP_RESP_TYPE = 0x33
_START_AUTHORIZE_CMD = 0x11
_CHALLENGE_CMD = 0x16
_CHALLENGE_RESPONSE_CMD = 0x17
_ABBOTT_VENDOR_ID = 0x1A61
_LIBRE2_PRODUCT_ID = 0x3950
_SERIAL_NO = construct.Struct(
message_type=construct.Const(_SERIAL_NUMBER_RESPONSE_TYPE, construct.Byte),
length=construct.Const(14, construct.Byte),
serial_number=construct.PaddedString(13, "ascii"),
termination=construct.Const(0, construct.Byte),
)
_CHALLENGE = construct.Struct(
message_type=construct.Const(_ENCRYPTION_SETUP_RESP_TYPE, construct.Byte),
length=construct.Const(16, construct.Byte),
subcmd=construct.Const(_CHALLENGE_CMD, construct.Byte),
challenge=construct.Bytes(8),
iv=construct.Bytes(7),
)
_CHALLENGE_RESPONSE = construct.Struct(
message_type=construct.Const(_ENCRYPTION_SETUP_REQ_TYPE, construct.Byte),
length=construct.Const(26, construct.Byte),
subcmd=construct.Const(_CHALLENGE_RESPONSE_CMD, construct.Byte),
challenge_response_encrypted=construct.Bytes(16),
const=construct.Const(1, construct.Byte),
mac=construct.Bytes(8),
)
def main():
if sys.version_info < (3, 7):
raise Exception("Unsupported Python version, please use at least Python 3.7.")
parser = argparse.ArgumentParser()
parser.add_argument(
"--device_address",
action="store",
type=str,
help=(
"Device address (busnum.devnum) of the device to extract capture"
" of. If none provided, device descriptors will be relied on."
),
)
parser.add_argument(
"--vlog",
action="store",
required=False,
type=int,
help=(
"Python logging level. See the levels at"
" https://docs.python.org/3/library/logging.html#logging-levels"
),
)
parser.add_argument(
"pcap_files",
action="store",
type=argparse.FileType(mode="rb"),
help="Path to the pcapng file with the USB capture.",
nargs="+",
)
args = parser.parse_args()
logging.basicConfig(level=args.vlog)
for pcap_file in args.pcap_files:
session = usbmon.pcapng.parse_stream(pcap_file, retag_urbs=False)
if not args.device_address:
for descriptor in session.device_descriptors.values():
if (
descriptor.vendor_id == _ABBOTT_VENDOR_ID
and descriptor.product_id == _LIBRE2_PRODUCT_ID
):
if (
args.device_address
and args.device_address != descriptor.address
):
raise Exception(
"Multiple Libre2 devices present in capture, please"
" provide a --device_address flag."
)
device_address = descriptor.address
else:
device_address = descriptor.address
descriptor = session.device_descriptors.get(device_address, None)
if descriptor:
assert descriptor.vendor_id == _ABBOTT_VENDOR_ID
assert descriptor.product_id == _LIBRE2_PRODUCT_ID
serial_number = "UNKNOWN"
challenge = "UNKNOWN"
iv = "UNKNOWN"
encrypted_challenge = "UNKNOWN"
mac = "UNKNOWN"
for first, second in session.in_pairs():
# Ignore stray callbacks/errors.
if not first.type == usbmon.constants.PacketType.SUBMISSION:
continue
if not first.address.startswith(f"{device_address}."):
# No need to check second, they will be linked.
continue
if first.xfer_type == usbmon.constants.XferType.INTERRUPT:
pass
elif (
first.xfer_type == usbmon.constants.XferType.CONTROL
and not first.setup_packet
or first.setup_packet.type == usbmon.setup.Type.CLASS
):
pass
else:
continue
if first.direction == usbmon.constants.Direction.OUT:
packet = first
else:
packet = second
if not packet.payload:
continue
assert len(packet.payload) >= 2
message_type = packet.payload[0]
if message_type == _SERIAL_NUMBER_RESPONSE_TYPE:
obj = _SERIAL_NO.parse(packet.payload)
serial_number = obj.serial_number
elif (
message_type == _ENCRYPTION_SETUP_RESP_TYPE
and packet.payload[2] == _CHALLENGE_CMD
):
obj = _CHALLENGE.parse(packet.payload)
challenge = obj.challenge.hex()
iv = obj.iv.hex()
elif (
message_type == _ENCRYPTION_SETUP_REQ_TYPE
and packet.payload[2] == _CHALLENGE_RESPONSE_CMD
):
obj = _CHALLENGE_RESPONSE.parse(packet.payload)
encrypted_challenge = obj.challenge_response_encrypted.hex()
mac = obj.mac.hex()
print(f"{serial_number},{challenge},{iv},{encrypted_challenge},{mac}")
if __name__ == "__main__":
main()
|
