mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-28 00:58:09 +00:00
334 lines
9.2 KiB
Python
334 lines
9.2 KiB
Python
#!/usr/bin/env python3
|
|
import argparse
|
|
import hashlib
|
|
import struct
|
|
|
|
import ecdsa
|
|
from ecdsa import BadSignatureError
|
|
|
|
SLOTS = 3
|
|
|
|
pubkeys_dev = {
|
|
1: "042c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991ae31a9c671a36543f46cea8fce6984608aa316aa0472a7eed08847440218cb2f",
|
|
2: "04edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f2211452c88a66eb8ac3c19a1cc3a3fc6d72506f6fce2025f738d8b55f29f22125eb0a4",
|
|
3: "04665f660a5052be7a95546a02179058d93d3e08a779734914594346075bb0afd45113948d72cf3dc8f2b70ee02dc1695d051bb0c6da2a914a69045e3277682d3b",
|
|
}
|
|
|
|
privkeys_dev = {
|
|
1: "0x4444444444444444444444444444444444444444444444444444444444444444",
|
|
2: "0x4545454545454545454545454545454545454545454545454545454545454545",
|
|
3: "0xbfc4bca9c9c228a16639d3503d999a733a439210b64cebe757a4fd03ca46a5c8",
|
|
}
|
|
|
|
FWHEADER_SIZE = 1024
|
|
SIGNATURES_START = 6 * 4 + 8 + 512
|
|
INDEXES_START = SIGNATURES_START + 3 * 64
|
|
|
|
INDEXES_START_OLD = len("TRZR") + struct.calcsize("<I")
|
|
SIG_START = INDEXES_START_OLD + SLOTS + 1 + 52
|
|
|
|
|
|
def parse_args():
|
|
parser = argparse.ArgumentParser(
|
|
description="Commandline tool for signing Trezor firmware."
|
|
)
|
|
parser.add_argument("-f", "--file", dest="path", help="Firmware file to modify")
|
|
|
|
return parser.parse_args()
|
|
|
|
|
|
def pad_to_size(data, size):
|
|
if len(data) > size:
|
|
raise ValueError("Chunk too big already")
|
|
if len(data) == size:
|
|
return data
|
|
return data + b"\xFF" * (size - len(data))
|
|
|
|
|
|
# see memory.h for details
|
|
|
|
|
|
def prepare_hashes(data):
|
|
# process chunks
|
|
start = 0
|
|
end = (64 - 1) * 1024
|
|
hashes = []
|
|
for i in range(16):
|
|
sector = data[start:end]
|
|
if len(sector) > 0:
|
|
chunk = pad_to_size(sector, end - start)
|
|
hashes.append(hashlib.sha256(chunk).digest())
|
|
else:
|
|
hashes.append(b"\x00" * 32)
|
|
start = end
|
|
end += 64 * 1024
|
|
return hashes
|
|
|
|
|
|
def check_hashes(data):
|
|
expected_hashes = data[0x20 : 0x20 + 16 * 32]
|
|
hashes = b""
|
|
for h in prepare_hashes(data[FWHEADER_SIZE:]):
|
|
hashes += h
|
|
|
|
if expected_hashes == hashes:
|
|
print("HASHES OK")
|
|
else:
|
|
print("HASHES NOT OK")
|
|
|
|
|
|
def update_hashes_in_header(data):
|
|
# Store hashes in the firmware header
|
|
data = bytearray(data)
|
|
o = 0
|
|
for h in prepare_hashes(data[FWHEADER_SIZE:]):
|
|
data[0x20 + o : 0x20 + o + 32] = h
|
|
o += 32
|
|
return bytes(data)
|
|
|
|
|
|
def get_header(data, zero_signatures=False):
|
|
if not zero_signatures:
|
|
return data[:FWHEADER_SIZE]
|
|
else:
|
|
data = bytearray(data[:FWHEADER_SIZE])
|
|
data[SIGNATURES_START : SIGNATURES_START + 3 * 64 + 3] = b"\x00" * (3 * 64 + 3)
|
|
return bytes(data)
|
|
|
|
|
|
def check_size(data):
|
|
size = struct.unpack("<L", data[12:16])[0]
|
|
assert size == len(data) - 1024
|
|
|
|
|
|
def check_signatures(data):
|
|
# Analyses given firmware and prints out
|
|
# status of included signatures
|
|
|
|
indexes = [x for x in data[INDEXES_START : INDEXES_START + SLOTS]]
|
|
|
|
to_sign = get_header(data, zero_signatures=True)
|
|
fingerprint = hashlib.sha256(to_sign).hexdigest()
|
|
|
|
print("Firmware fingerprint:", fingerprint)
|
|
|
|
used = []
|
|
for x in range(SLOTS):
|
|
signature = data[SIGNATURES_START + 64 * x : SIGNATURES_START + 64 * x + 64]
|
|
|
|
if indexes[x] == 0:
|
|
print(f"Slot #{x + 1}", "is empty")
|
|
else:
|
|
pubkeys = pubkeys_dev
|
|
pk = pubkeys[indexes[x]]
|
|
verify = ecdsa.VerifyingKey.from_string(
|
|
bytes.fromhex(pk)[1:],
|
|
curve=ecdsa.curves.SECP256k1,
|
|
hashfunc=hashlib.sha256,
|
|
)
|
|
|
|
try:
|
|
verify.verify(signature, to_sign, hashfunc=hashlib.sha256)
|
|
|
|
if indexes[x] in used:
|
|
print(f"Slot #{x + 1} signature: DUPLICATE", signature.hex())
|
|
else:
|
|
used.append(indexes[x])
|
|
print(f"Slot #{x + 1} signature: VALID", signature.hex())
|
|
|
|
except Exception:
|
|
print(f"Slot #{x + 1} signature: INVALID", signature.hex())
|
|
|
|
|
|
def modify(data, slot, index, signature):
|
|
data = bytearray(data)
|
|
# put index to data
|
|
data[INDEXES_START + slot - 1] = index
|
|
# put signature to data
|
|
data[SIGNATURES_START + 64 * (slot - 1) : SIGNATURES_START + 64 * slot] = signature
|
|
return bytes(data)
|
|
|
|
|
|
def sign(data, slot, secexp):
|
|
key = ecdsa.SigningKey.from_secret_exponent(
|
|
secexp=int(secexp, 16),
|
|
curve=ecdsa.curves.SECP256k1,
|
|
hashfunc=hashlib.sha256,
|
|
)
|
|
|
|
to_sign = get_header(data, zero_signatures=True)
|
|
|
|
# Locate proper index of current signing key
|
|
pubkey = "04" + key.get_verifying_key().to_string().hex()
|
|
index = None
|
|
|
|
pubkeys = pubkeys_dev
|
|
for i, pk in pubkeys.items():
|
|
if pk == pubkey:
|
|
index = i
|
|
break
|
|
|
|
if index is None:
|
|
raise Exception("Unable to find private key index. Unknown private key?")
|
|
|
|
signature = key.sign_deterministic(to_sign, hashfunc=hashlib.sha256)
|
|
|
|
return modify(data, slot, index, signature)
|
|
|
|
|
|
def prepare_old(data):
|
|
# Takes raw OR signed firmware and clean out metadata structure
|
|
# This produces 'clean' data for signing
|
|
|
|
meta = b"TRZR" # magic
|
|
if data[:4] == b"TRZR":
|
|
meta += data[4 : 4 + struct.calcsize("<I")]
|
|
else:
|
|
meta += struct.pack("<I", len(data)) # length of the code
|
|
meta += b"\x00" * SLOTS # signature index #1-#3
|
|
meta += b"\x01" # flags
|
|
meta += b"\x00" * 52 # reserved
|
|
meta += b"\x00" * 64 * SLOTS # signature #1-#3
|
|
|
|
if data[:4] == b"TRZR":
|
|
# Replace existing header
|
|
out = meta + data[len(meta) :]
|
|
else:
|
|
# create data from meta + code
|
|
out = meta + data
|
|
|
|
return out
|
|
|
|
|
|
def check_signatures_old(data):
|
|
# Analyses given firmware and prints out
|
|
# status of included signatures
|
|
|
|
try:
|
|
indexes = [ord(x) for x in data[INDEXES_START_OLD : INDEXES_START_OLD + SLOTS]]
|
|
except TypeError:
|
|
indexes = [x for x in data[INDEXES_START_OLD : INDEXES_START_OLD + SLOTS]]
|
|
|
|
to_sign = prepare_old(data)[256:] # without meta
|
|
fingerprint = hashlib.sha256(to_sign).hexdigest()
|
|
|
|
print("Firmware fingerprint:", fingerprint)
|
|
|
|
used = []
|
|
for x in range(SLOTS):
|
|
signature = data[SIG_START + 64 * x : SIG_START + 64 * x + 64]
|
|
|
|
if indexes[x] == 0:
|
|
print("Slot #%d" % (x + 1), "is empty")
|
|
else:
|
|
pubkeys = pubkeys_dev
|
|
pk = pubkeys[indexes[x]]
|
|
verify = ecdsa.VerifyingKey.from_string(
|
|
bytes.fromhex(pk)[1:],
|
|
curve=ecdsa.curves.SECP256k1,
|
|
hashfunc=hashlib.sha256,
|
|
)
|
|
|
|
try:
|
|
verify.verify(signature, to_sign, hashfunc=hashlib.sha256)
|
|
|
|
if indexes[x] in used:
|
|
print("Slot #%d signature: DUPLICATE" % (x + 1), signature.hex())
|
|
else:
|
|
used.append(indexes[x])
|
|
print("Slot #%d signature: VALID" % (x + 1), signature.hex())
|
|
|
|
except BadSignatureError:
|
|
print("Slot #%d signature: INVALID" % (x + 1), signature.hex())
|
|
|
|
|
|
def modify_old(data, slot, index, signature):
|
|
# Replace signature in data
|
|
|
|
# Put index to data
|
|
data = (
|
|
data[: INDEXES_START_OLD + slot - 1]
|
|
+ bytes([index])
|
|
+ data[INDEXES_START_OLD + slot :]
|
|
)
|
|
|
|
# Put signature to data
|
|
data = (
|
|
data[: SIG_START + 64 * (slot - 1)] + signature + data[SIG_START + 64 * slot :]
|
|
)
|
|
|
|
return data
|
|
|
|
|
|
def sign_old(data, slot, secexp):
|
|
key = ecdsa.SigningKey.from_secret_exponent(
|
|
secexp=int(secexp, 16),
|
|
curve=ecdsa.curves.SECP256k1,
|
|
hashfunc=hashlib.sha256,
|
|
)
|
|
|
|
to_sign = prepare_old(data)[256:] # without meta
|
|
|
|
# Locate proper index of current signing key
|
|
pubkey = "04" + key.get_verifying_key().to_string().hex()
|
|
index = None
|
|
|
|
pubkeys = pubkeys_dev
|
|
|
|
for i, pk in pubkeys.items():
|
|
if pk == pubkey:
|
|
index = i
|
|
break
|
|
|
|
if index is None:
|
|
raise Exception("Unable to find private key index. Unknown private key?")
|
|
|
|
signature = key.sign_deterministic(to_sign, hashfunc=hashlib.sha256)
|
|
|
|
return modify_old(data, slot, index, signature)
|
|
|
|
|
|
def main(args):
|
|
if not args.path:
|
|
raise Exception("-f/--file is required")
|
|
|
|
data = open(args.path, "rb").read()
|
|
assert len(data) % 4 == 0
|
|
|
|
if data[:4] != b"TRZF":
|
|
raise Exception("Firmware header expected")
|
|
|
|
data = update_hashes_in_header(data)
|
|
|
|
print(f"Firmware size {len(data)} bytes")
|
|
|
|
check_size(data)
|
|
check_signatures(data)
|
|
check_hashes(data)
|
|
|
|
data = sign(data, 1, privkeys_dev[1])
|
|
data = sign(data, 2, privkeys_dev[2])
|
|
data = sign(data, 3, privkeys_dev[3])
|
|
check_signatures(data)
|
|
check_hashes(data)
|
|
|
|
fp = open(args.path, "wb")
|
|
fp.write(data)
|
|
fp.close()
|
|
|
|
data = prepare_old(data)
|
|
check_signatures_old(data)
|
|
data = sign_old(data, 1, privkeys_dev[1])
|
|
data = sign_old(data, 2, privkeys_dev[2])
|
|
data = sign_old(data, 3, privkeys_dev[3])
|
|
check_signatures_old(data)
|
|
|
|
fp = open(args.path, "wb")
|
|
fp.write(data)
|
|
fp.close()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
args = parse_args()
|
|
main(args)
|