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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-12-17 11:58:13 +00:00
trezor-firmware/bootloader/firmware_sign.py
2016-05-24 20:31:01 +02:00

190 lines
6.4 KiB
Python
Executable File

#!/usr/bin/env python2
import argparse
import hashlib
import struct
import binascii
import ecdsa
SLOTS = 3
pubkeys = {
1: '04d571b7f148c5e4232c3814f777d8faeaf1a84216c78d569b71041ffc768a5b2d810fc3bb134dd026b57e65005275aedef43e155f48fc11a32ec790a93312bd58',
2: '0463279c0c0866e50c05c799d32bd6bab0188b6de06536d1109d2ed9ce76cb335c490e55aee10cc901215132e853097d5432eda06b792073bd7740c94ce4516cb1',
3: '0443aedbb6f7e71c563f8ed2ef64ec9981482519e7ef4f4aa98b27854e8c49126d4956d300ab45fdc34cd26bc8710de0a31dbdf6de7435fd0b492be70ac75fde58',
4: '04877c39fd7c62237e038235e9c075dab261630f78eeb8edb92487159fffedfdf6046c6f8b881fa407c4a4ce6c28de0b19c1f4e29f1fcbc5a58ffd1432a3e0938a',
5: '047384c51ae81add0a523adbb186c91b906ffb64c2c765802bf26dbd13bdf12c319e80c2213a136c8ee03d7874fd22b70d68e7dee469decfbbb510ee9a460cda45',
}
INDEXES_START = len('TRZR') + struct.calcsize('<I')
SIG_START = INDEXES_START + 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")
parser.add_argument('-s', '--sign', dest='sign', action='store_true', help="Add signature to firmware slot")
parser.add_argument('-p', '--pem', dest='pem', action='store_true', help="Use PEM instead of SECEXP")
parser.add_argument('-g', '--generate', dest='generate', action='store_true', help='Generate new ECDSA keypair')
return parser.parse_args()
def prepare(data):
# Takes raw OR signed firmware and clean out metadata structure
# This produces 'clean' data for signing
meta = 'TRZR' # magic
if data[:4] == 'TRZR':
meta += data[4:4 + struct.calcsize('<I')]
else:
meta += struct.pack('<I', len(data)) # length of the code
meta += '\x00' * SLOTS # signature index #1-#3
meta += '\x01' # flags
meta += '\x00' * 52 # reserved
meta += '\x00' * 64 * SLOTS # signature #1-#3
if data[:4] == 'TRZR':
# Replace existing header
out = meta + data[len(meta):]
else:
# create data from meta + code
out = meta + data
return out
def check_signatures(data):
# Analyses given firmware and prints out
# status of included signatures
indexes = [ ord(x) for x in data[INDEXES_START:INDEXES_START + SLOTS] ]
to_sign = prepare(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:
pk = pubkeys[indexes[x]]
verify = ecdsa.VerifyingKey.from_string(binascii.unhexlify(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), binascii.hexlify(signature)
else:
used.append(indexes[x])
print "Slot #%d signature: VALID" % (x + 1), binascii.hexlify(signature)
except:
print "Slot #%d signature: INVALID" % (x + 1), binascii.hexlify(signature)
def modify(data, slot, index, signature):
# Replace signature in data
# Put index to data
data = data[:INDEXES_START + slot - 1 ] + chr(index) + data[INDEXES_START + slot:]
# Put signature to data
data = data[:SIG_START + 64 * (slot - 1) ] + signature + data[SIG_START + 64 * slot:]
return data
def sign(data, is_pem):
# Ask for index and private key and signs the firmware
slot = int(raw_input('Enter signature slot (1-%d): ' % SLOTS))
if slot < 1 or slot > SLOTS:
raise Exception("Invalid slot")
if is_pem:
print "Paste ECDSA private key in PEM format and press Enter:"
print "(blank private key removes the signature on given index)"
pem_key = ''
while True:
key = raw_input()
pem_key += key + "\n"
if key == '':
break
if pem_key.strip() == '':
# Blank key,let's remove existing signature from slot
return modify(data, slot, 0, '\x00' * 64)
key = ecdsa.SigningKey.from_pem(pem_key)
else:
print "Paste SECEXP (in hex) and press Enter:"
print "(blank private key removes the signature on given index)"
secexp = raw_input()
if secexp.strip() == '':
# Blank key,let's remove existing signature from slot
return modify(data, slot, 0, '\x00' * 64)
key = ecdsa.SigningKey.from_secret_exponent(secexp = int(secexp, 16), curve=ecdsa.curves.SECP256k1, hashfunc=hashlib.sha256)
to_sign = prepare(data)[256:] # without meta
# Locate proper index of current signing key
pubkey = '04' + binascii.hexlify(key.get_verifying_key().to_string())
index = None
for i, pk in pubkeys.iteritems():
if pk == pubkey:
index = i
break
if index == 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 main(args):
if args.generate:
key = ecdsa.SigningKey.generate(
curve=ecdsa.curves.SECP256k1,
hashfunc=hashlib.sha256)
print "PRIVATE KEY (SECEXP):"
print binascii.hexlify(key.to_string())
print
print "PRIVATE KEY (PEM):"
print key.to_pem()
print "PUBLIC KEY:"
print '04' + binascii.hexlify(key.get_verifying_key().to_string())
return
if not args.path:
raise Exception("-f/--file is required")
data = open(args.path, 'rb').read()
assert len(data) % 4 == 0
if data[:4] != 'TRZR':
print "Metadata has been added..."
data = prepare(data)
if data[:4] != 'TRZR':
raise Exception("Firmware header expected")
print "Firmware size %d bytes" % len(data)
check_signatures(data)
if args.sign:
data = sign(data, args.pem)
check_signatures(data)
fp = open(args.path, 'w')
fp.write(data)
fp.close()
if __name__ == '__main__':
args = parse_args()
main(args)