trezor-agent/sshagent/trezor/client.py
2015-08-17 17:59:05 +03:00

205 lines
6.5 KiB
Python

import io
import re
import struct
import binascii
import time
import os
from .. import util
from .. import formats
from . import trezor_library
import logging
log = logging.getLogger(__name__)
class Client(object):
curve_name = 'nist256p1'
def __init__(self, factory=trezor_library):
self.factory = factory
self.client = self.factory.client()
f = self.client.features
log.debug('connected to Trezor %s', f.device_id)
log.debug('label : %s', f.label)
log.debug('vendor : %s', f.vendor)
version = [f.major_version, f.minor_version, f.patch_version]
log.debug('version : %s', '.'.join([str(v) for v in version]))
log.debug('revision : %s', binascii.hexlify(f.revision))
def __enter__(self):
return self
def __exit__(self, *args):
log.info('disconnected from Trezor')
self.client.close()
def get_identity(self, label, protocol=None):
identity = _string_to_identity(label, self.factory.identity_type)
if protocol is not None:
identity.proto = protocol
return identity
def get_public_key(self, identity):
assert identity.proto == 'ssh'
label = _identity_to_string(identity)
log.info('getting "%s" public key from Trezor...', label)
addr = _get_address(identity)
node = self.client.get_public_node(addr, self.curve_name)
pubkey = node.node.public_key
return formats.export_public_key(pubkey=pubkey, label=label)
def sign_ssh_challenge(self, identity, blob):
assert identity.proto == 'ssh'
label = _identity_to_string(identity)
msg = _parse_ssh_blob(blob)
log.info('please confirm user "%s" login to "%s" using Trezor...',
msg['user'], label)
visual = identity.path # not signed when proto='ssh'
result = self.client.sign_identity(identity=identity,
challenge_hidden=blob,
challenge_visual=visual,
ecdsa_curve_name=self.curve_name)
verifying_key = formats.decompress_pubkey(result.public_key)
public_key_blob = formats.serialize_verifying_key(verifying_key)
assert public_key_blob == msg['public_key']['blob']
assert len(result.signature) == 65
assert result.signature[0] == b'\x00'
sig = result.signature[1:]
r = util.bytes2num(sig[:32])
s = util.bytes2num(sig[32:])
return (r, s)
def sign_identity(self, label, expected_address=None):
from bitcoin import pubkey_to_address
visual = time.strftime('%d/%m/%y %H:%M:%S')
hidden = os.urandom(64)
identity = self.get_identity(label=label)
derivation_path = _get_address(identity)
node = self.client.get_public_node(derivation_path)
address = pubkey_to_address(node.node.public_key)
log.info('address: %s', address)
if expected_address is None:
log.warning('Specify Bitcoin address: %s', address)
self.client.get_address(n=derivation_path,
coin_name='Bitcoin',
show_display=True)
return 2
assert expected_address == address
result = self.client.sign_identity(identity=identity,
challenge_hidden=hidden,
challenge_visual=visual)
assert address == result.address
assert node.node.public_key == result.public_key
digest = message_digest(hidden=hidden, visual=visual)
return _validate_signature(result=result, digest=digest)
def _validate_signature(result, digest):
sig = result.signature[1:]
curve = formats.ecdsa.SECP256k1
verifying_key = formats.decompress_pubkey(result.public_key,
curve=curve)
log.debug('digest: %s', binascii.hexlify(digest))
signature = (util.bytes2num(sig[:32]),
util.bytes2num(sig[32:]))
log.debug('signature: %s', signature)
try:
verifying_key.verify_digest(signature=signature,
digest=digest,
sigdecode=lambda sig, _: sig)
except formats.ecdsa.BadSignatureError:
log.error('signature: ERROR')
return 1
log.info('signature: OK')
return 0
def message_digest(hidden, visual):
from bitcoin import electrum_sig_hash
hidden_digest = formats.hashfunc(hidden).digest()
visual_digest = formats.hashfunc(visual).digest()
return electrum_sig_hash(hidden_digest + visual_digest)
_identity_regexp = re.compile(''.join([
'^'
r'(?:(?P<proto>.*)://)?',
r'(?:(?P<user>.*)@)?',
r'(?P<host>.*?)',
r'(?::(?P<port>\w*))?',
r'(?P<path>/.*)?',
'$'
]))
def _string_to_identity(s, identity_type):
m = _identity_regexp.match(s)
result = m.groupdict()
log.debug('parsed identity: %s', result)
kwargs = {k: v for k, v in result.items() if v}
return identity_type(**kwargs)
def _identity_to_string(identity):
result = []
if identity.proto:
result.append(identity.proto + '://')
if identity.user:
result.append(identity.user + '@')
result.append(identity.host)
if identity.port:
result.append(':' + identity.port)
if identity.path:
result.append(identity.path)
return ''.join(result)
def _get_address(identity):
index = struct.pack('<L', identity.index)
addr = index + _identity_to_string(identity)
log.debug('address string: %r', addr)
digest = formats.hashfunc(addr).digest()
s = io.BytesIO(bytearray(digest))
hardened = 0x80000000
address_n = [13] + list(util.recv(s, '<LLLL'))
return [(hardened | value) for value in address_n]
def _parse_ssh_blob(data):
res = {}
if data:
i = io.BytesIO(data)
res['nonce'] = util.read_frame(i)
i.read(1) # TBD
res['user'] = util.read_frame(i)
res['conn'] = util.read_frame(i)
res['auth'] = util.read_frame(i)
i.read(1) # TBD
res['key_type'] = util.read_frame(i)
public_key = util.read_frame(i)
res['public_key'] = formats.parse_pubkey(public_key)
assert not i.read()
log.debug('%s: user %r via %r (%r)',
res['conn'], res['user'], res['auth'], res['key_type'])
log.debug('nonce: %s', binascii.hexlify(res['nonce']))
log.debug('fingerprint: %s', res['public_key']['fingerprint'])
return res