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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-12-25 07:48:10 +00:00
trezor-firmware/trezorlib/firmware.py
2018-08-13 18:22:19 +02:00

200 lines
5.4 KiB
Python

import binascii
import construct as c
import pyblake2
from . import cosi, messages as proto, tools
def bytes_not(data):
return bytes(~b & 0xff for b in data)
# fmt: off
Toif = c.Struct(
"magic" / c.Const(b"TOI"),
"format" / c.Enum(c.Byte, full_color=b"f", grayscale=b"g"),
"width" / c.Int16ul,
"height" / c.Int16ul,
"data" / c.Prefixed(c.Int32ul, c.GreedyBytes),
)
VendorTrust = c.Transformed(c.BitStruct(
"reserved" / c.Padding(9),
"show_vendor_string" / c.Flag,
"require_user_click" / c.Flag,
"red_background" / c.Flag,
"delay" / c.BitsInteger(4),
), bytes_not, 2, bytes_not, 2)
VendorHeader = c.Struct(
"_start_offset" / c.Tell,
"magic" / c.Const(b"TRZV"),
"_header_len" / c.Padding(4),
"expiry" / c.Int32ul,
"version" / c.Struct(
"major" / c.Int8ul,
"minor" / c.Int8ul,
),
"vendor_sigs_required" / c.Int8ul,
"vendor_sigs_n" / c.Rebuild(c.Int8ul, c.len_(c.this.pubkeys)),
"vendor_trust" / VendorTrust,
"reserved" / c.Padding(14),
"pubkeys" / c.Bytes(32)[c.this.vendor_sigs_n],
"vendor_string" / c.Aligned(4, c.PascalString(c.Int8ul, "utf-8")),
"vendor_image" / Toif,
"_data_end_offset" / c.Tell,
c.Padding(-(c.this._data_end_offset + 65) % 512),
"sigmask" / c.Byte,
"signature" / c.Bytes(64),
"_end_offset" / c.Tell,
"header_len" / c.Pointer(
c.this._start_offset + 4,
c.Rebuild(c.Int32ul, c.this._end_offset - c.this._start_offset)
),
)
VersionLong = c.Struct(
"major" / c.Int8ul,
"minor" / c.Int8ul,
"patch" / c.Int8ul,
"build" / c.Int8ul,
)
FirmwareHeader = c.Struct(
"_start_offset" / c.Tell,
"magic" / c.Const(b"TRZF"),
"_header_len" / c.Padding(4),
"expiry" / c.Int32ul,
"code_length" / c.Rebuild(
c.Int32ul,
lambda this:
len(this._.code) if "code" in this._
else (this.code_length or 0)),
"version" / VersionLong,
"fix_version" / VersionLong,
"reserved" / c.Padding(8),
"hashes" / c.Bytes(32)[16],
"reserved" / c.Padding(415),
"sigmask" / c.Byte,
"signature" / c.Bytes(64),
"_end_offset" / c.Tell,
"header_len" / c.Pointer(
c.this._start_offset + 4,
c.Rebuild(c.Int32ul, c.this._end_offset - c.this._start_offset)
),
)
Firmware = c.Struct(
"vendor_header" / VendorHeader,
"firmware_header" / FirmwareHeader,
"code" / c.Bytes(c.this.firmware_header.code_length),
c.Terminated,
)
# fmt: on
def validate_firmware(filename):
with open(filename, "rb") as f:
data = f.read()
if data[:6] == b"54525a":
data = binascii.unhexlify(data)
try:
fw = Firmware.parse(data)
except Exception as e:
raise ValueError("Invalid firmware image format") from e
vendor = fw.vendor_header
header = fw.firmware_header
print(
"Vendor header from {}, version {}.{}".format(
vendor.vendor_string, vendor.version.major, vendor.version.minor
)
)
print(
"Firmware version {v.major}.{v.minor}.{v.patch} build {v.build}".format(
v=header.version
)
)
# rebuild header without signatures
stripped_header = header.copy()
stripped_header.sigmask = 0
stripped_header.signature = b"\0" * 64
header_bytes = FirmwareHeader.build(stripped_header)
digest = pyblake2.blake2s(header_bytes).digest()
print("Fingerprint: {}".format(binascii.hexlify(digest).decode("ascii")))
global_pk = cosi.combine_keys(
vendor.pubkeys[i] for i in range(8) if header.sigmask & (1 << i)
)
try:
cosi.verify(header.signature, digest, global_pk)
print("Signature OK")
except Exception:
print("Signature FAILED")
raise
# ====== Client functions ====== #
@tools.session
def update(client, fp):
if client.features.bootloader_mode is False:
raise RuntimeError("Device must be in bootloader mode")
data = fp.read()
resp = client.call(proto.FirmwareErase(length=len(data)))
if isinstance(resp, proto.Failure) and resp.code == proto.FailureType.FirmwareError:
return False
# TREZORv1 method
if isinstance(resp, proto.Success):
# fingerprint = hashlib.sha256(data[256:]).hexdigest()
# LOG.debug("Firmware fingerprint: " + fingerprint)
resp = client.call(proto.FirmwareUpload(payload=data))
if isinstance(resp, proto.Success):
return True
elif (
isinstance(resp, proto.Failure)
and resp.code == proto.FailureType.FirmwareError
):
return False
raise RuntimeError("Unexpected result %s" % resp)
# TREZORv2 method
if isinstance(resp, proto.FirmwareRequest):
import pyblake2
while True:
payload = data[resp.offset : resp.offset + resp.length]
digest = pyblake2.blake2s(payload).digest()
resp = client.call(proto.FirmwareUpload(payload=payload, hash=digest))
if isinstance(resp, proto.FirmwareRequest):
continue
elif isinstance(resp, proto.Success):
return True
elif (
isinstance(resp, proto.Failure)
and resp.code == proto.FailureType.FirmwareError
):
return False
raise RuntimeError("Unexpected result %s" % resp)
raise RuntimeError("Unexpected message %s" % resp)