136 lines
4.4 KiB
Python
136 lines
4.4 KiB
Python
import binascii
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import io
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import logging
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import re
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import struct
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from . import factory, formats, util
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log = logging.getLogger(__name__)
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class Client(object):
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def __init__(self, loader=factory.load, curve=formats.CURVE_NIST256):
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client_wrapper = loader()
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self.client = client_wrapper.connection
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self.identity_type = client_wrapper.identity_type
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self.device_name = client_wrapper.device_name
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self.curve = curve
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def __enter__(self):
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msg = 'Hello World!'
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assert self.client.ping(msg) == msg
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return self
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def __exit__(self, *args):
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log.info('disconnected from %s', self.device_name)
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self.client.clear_session() # forget PIN and shutdown screen
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self.client.close()
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def get_identity(self, label, index=0):
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identity = string_to_identity(label, self.identity_type)
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identity.proto = 'ssh'
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identity.index = index
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return identity
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def get_public_key(self, label):
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identity = self.get_identity(label=label)
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label = identity_to_string(identity) # canonize key label
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log.info('getting "%s" public key (%s) from %s...',
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label, self.curve, self.device_name)
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addr = _get_address(identity)
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node = self.client.get_public_node(n=addr,
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ecdsa_curve_name=self.curve)
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pubkey = node.node.public_key
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vk = formats.decompress_pubkey(pubkey=pubkey, curve_name=self.curve)
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return formats.export_public_key(vk=vk, label=label)
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def sign_ssh_challenge(self, label, blob, visual=''):
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identity = self.get_identity(label=label)
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msg = _parse_ssh_blob(blob)
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log.debug('%s: user %r via %r (%r)',
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msg['conn'], msg['user'], msg['auth'], msg['key_type'])
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log.debug('nonce: %s', binascii.hexlify(msg['nonce']))
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log.debug('fingerprint: %s', msg['public_key']['fingerprint'])
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log.info('please confirm user "%s" login to "%s" using %s...',
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msg['user'], label, self.device_name)
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result = self.client.sign_identity(identity=identity,
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challenge_hidden=blob,
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challenge_visual=visual,
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ecdsa_curve_name=self.curve)
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verifying_key = formats.decompress_pubkey(pubkey=result.public_key,
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curve_name=self.curve)
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key_type, blob = formats.serialize_verifying_key(verifying_key)
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assert blob == msg['public_key']['blob']
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assert key_type == msg['key_type']
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assert len(result.signature) == 65
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assert result.signature[:1] == bytearray([0])
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return result.signature[1:]
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_identity_regexp = re.compile(''.join([
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'^'
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r'(?:(?P<proto>.*)://)?',
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r'(?:(?P<user>.*)@)?',
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r'(?P<host>.*?)',
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r'(?::(?P<port>\w*))?',
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r'(?P<path>/.*)?',
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'$'
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]))
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def string_to_identity(s, identity_type):
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m = _identity_regexp.match(s)
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result = m.groupdict()
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log.debug('parsed identity: %s', result)
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kwargs = {k: v for k, v in result.items() if v}
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return identity_type(**kwargs)
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def identity_to_string(identity):
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result = []
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if identity.proto:
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result.append(identity.proto + '://')
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if identity.user:
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result.append(identity.user + '@')
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result.append(identity.host)
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if identity.port:
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result.append(':' + identity.port)
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if identity.path:
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result.append(identity.path)
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return ''.join(result)
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def _get_address(identity):
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index = struct.pack('<L', identity.index)
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addr = index + identity_to_string(identity).encode('ascii')
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log.debug('address string: %r', addr)
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digest = formats.hashfunc(addr).digest()
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s = io.BytesIO(bytearray(digest))
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hardened = 0x80000000
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address_n = [13] + list(util.recv(s, '<LLLL'))
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return [(hardened | value) for value in address_n]
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def _parse_ssh_blob(data):
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res = {}
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i = io.BytesIO(data)
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res['nonce'] = util.read_frame(i)
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i.read(1) # SSH2_MSG_USERAUTH_REQUEST == 50 (from ssh2.h, line 108)
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res['user'] = util.read_frame(i)
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res['conn'] = util.read_frame(i)
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res['auth'] = util.read_frame(i)
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i.read(1) # have_sig == 1 (from sshconnect2.c, line 1056)
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res['key_type'] = util.read_frame(i)
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public_key = util.read_frame(i)
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res['public_key'] = formats.parse_pubkey(public_key)
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assert not i.read()
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return res
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