/usr/lib/python3/dist-packages/pskc/serialiser.py is in python3-pskc 1.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 | # serialiser.py - PSKC file parsing functions
# coding: utf-8
#
# Copyright (C) 2016-2017 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
"""Module for serialising PSKC files to XML."""
import base64
from pskc.key import EncryptedIntegerValue, EncryptedValue
from pskc.xml import find, mk_elem, move_namespaces, reformat, tostring
def my_b64encode(value):
"""Wrap around b64encode to handle types correctly."""
if not isinstance(value, type(b'')):
value = value.encode() # pragma: no cover (Python 3 specific)
return base64.b64encode(value).decode()
class PSKCSerialiser(object):
@classmethod
def serialise_file(cls, pskc, output):
xml = tostring(cls.serialise_document(pskc))
try:
output.write(xml)
except TypeError: # pragma: no cover (Python 3 specific)
# fall back to writing as string for Python 3
output.write(xml.decode('utf-8'))
@classmethod
def serialise_document(cls, pskc):
container = mk_elem('pskc:KeyContainer', Version=pskc.version,
Id=pskc.id)
cls.serialise_encryption(pskc.encryption, container)
cls.serialise_mac(pskc.mac, container)
for device in pskc.devices:
cls.serialise_key_package(device, container)
return cls.serialise_signature(pskc.signature, container)
@classmethod
def serialise_encryption(cls, encryption, container):
if all(x is None
for x in (encryption.id, encryption.key_name, encryption.key,
encryption.derivation.algorithm)):
return
encryption_key = mk_elem(container, 'pskc:EncryptionKey',
Id=encryption.id, empty=True)
if encryption.derivation.algorithm:
cls.serialise_key_derivation(
encryption.derivation, encryption_key, encryption.key_names)
else:
for name in encryption.key_names:
mk_elem(encryption_key, 'ds:KeyName', name)
@classmethod
def serialise_key_derivation(cls, derivation, encryption_key, key_names):
derived_key = mk_elem(encryption_key, 'xenc11:DerivedKey', empty=True)
key_derivation = mk_elem(derived_key, 'xenc11:KeyDerivationMethod',
Algorithm=derivation.algorithm)
if derivation.algorithm.endswith('#pbkdf2'):
pbkdf2 = mk_elem(key_derivation, 'xenc11:PBKDF2-params',
empty=True)
if derivation.pbkdf2_salt:
salt = mk_elem(pbkdf2, 'Salt', empty=True)
mk_elem(salt, 'Specified',
base64.b64encode(derivation.pbkdf2_salt).decode())
mk_elem(pbkdf2, 'IterationCount', derivation.pbkdf2_iterations)
mk_elem(pbkdf2, 'KeyLength', derivation.pbkdf2_key_length)
mk_elem(pbkdf2, 'PRF', derivation.pbkdf2_prf)
# TODO: serialise ReferenceList/DataReference
for name in key_names:
mk_elem(derived_key, 'xenc11:MasterKeyName', name)
@classmethod
def serialise_mac(cls, mac, container):
if not mac.algorithm and not mac.key:
return
mac_method = mk_elem(
container, 'pskc:MACMethod', Algorithm=mac.algorithm, empty=True)
mac_key = mk_elem(mac_method, 'pskc:MACKey', empty=True)
mk_elem(
mac_key, 'xenc:EncryptionMethod',
Algorithm=mac.pskc.encryption.algorithm)
cipher_data = mk_elem(mac_key, 'xenc:CipherData', empty=True)
if mac.key_cipher_value:
mk_elem(cipher_data, 'xenc:CipherValue',
base64.b64encode(mac.key_cipher_value).decode())
elif mac.key_plain_value:
mk_elem(cipher_data, 'xenc:CipherValue',
base64.b64encode(mac.pskc.encryption.encrypt_value(
mac.key_plain_value)).decode())
@classmethod
def serialise_key_package(cls, device, container):
key_package = mk_elem(container, 'pskc:KeyPackage', empty=True)
if any(x is not None
for x in (device.manufacturer, device.serial, device.model,
device.issue_no, device.device_binding,
device.start_date, device.expiry_date,
device.device_userid)):
device_info = mk_elem(key_package, 'pskc:DeviceInfo', empty=True)
mk_elem(device_info, 'pskc:Manufacturer', device.manufacturer)
mk_elem(device_info, 'pskc:SerialNo', device.serial)
mk_elem(device_info, 'pskc:Model', device.model)
mk_elem(device_info, 'pskc:IssueNo', device.issue_no)
mk_elem(device_info, 'pskc:DeviceBinding', device.device_binding)
mk_elem(device_info, 'pskc:StartDate', device.start_date)
mk_elem(device_info, 'pskc:ExpiryDate', device.expiry_date)
mk_elem(device_info, 'pskc:UserId', device.device_userid)
if device.crypto_module is not None:
crypto_module = mk_elem(key_package, 'pskc:CryptoModuleInfo',
empty=True)
mk_elem(crypto_module, 'pskc:Id', device.crypto_module)
for key in device.keys:
cls.serialise_key(key, key_package)
@classmethod
def serialise_key(cls, key, key_package):
key_elm = mk_elem(key_package, 'pskc:Key', empty=True, Id=key.id,
Algorithm=key.algorithm, )
mk_elem(key_elm, 'pskc:Issuer', key.issuer)
if any((key.algorithm_suite, key.challenge_encoding,
key.response_encoding, key.response_length)):
parameters = mk_elem(key_elm, 'pskc:AlgorithmParameters',
empty=True)
mk_elem(parameters, 'pskc:Suite', key.algorithm_suite)
mk_elem(parameters, 'pskc:ChallengeFormat',
Encoding=key.challenge_encoding,
Min=key.challenge_min_length,
Max=key.challenge_max_length,
CheckDigits=key.challenge_check)
mk_elem(parameters, 'pskc:ResponseFormat',
Encoding=key.response_encoding,
Length=key.response_length,
CheckDigits=key.response_check)
mk_elem(key_elm, 'pskc:KeyProfileId', key.key_profile)
mk_elem(key_elm, 'pskc:KeyReference', key.key_reference)
mk_elem(key_elm, 'pskc:FriendlyName', key.friendly_name)
cls.serialise_data(
key, 'secret', key_elm, 'pskc:Secret')
cls.serialise_data(
key, 'counter', key_elm, 'pskc:Counter')
cls.serialise_data(
key, 'time_offset', key_elm, 'pskc:Time')
cls.serialise_data(
key, 'time_interval', key_elm, 'pskc:TimeInterval')
cls.serialise_data(
key, 'time_drift', key_elm, 'pskc:TimeDrift')
mk_elem(key_elm, 'pskc:UserId', key.key_userid)
cls.serialise_policy(key.policy, key_elm)
@classmethod
def serialise_data(cls, key, field, key_elm, tag):
value = getattr(key, '_%s' % field, None)
pskc = key.device.pskc
# skip empty values
if value in (None, ''):
return
# get the value2text and encryption storage
if field == 'secret':
value2text = my_b64encode
encrypted_value_cls = EncryptedValue
else:
value2text = str
encrypted_value_cls = EncryptedIntegerValue
# find the data tag and create our tag under it
data = find(key_elm, 'pskc:Data')
if data is None:
data = mk_elem(key_elm, 'pskc:Data', empty=True)
element = mk_elem(data, tag, empty=True)
# see if we should encrypt the value
if field in pskc.encryption.fields and not hasattr(
value, 'get_value'):
value = encrypted_value_cls.create(pskc, value)
# write out value
if not hasattr(value, 'get_value'):
# unencrypted value
mk_elem(element, 'pskc:PlainValue', value2text(value))
else:
# encrypted value
encrypted_value = mk_elem(
element, 'pskc:EncryptedValue', empty=True)
mk_elem(encrypted_value, 'xenc:EncryptionMethod',
Algorithm=value.algorithm)
cipher_data = mk_elem(
encrypted_value, 'xenc:CipherData', empty=True)
mk_elem(cipher_data, 'xenc:CipherValue',
base64.b64encode(value.cipher_value).decode())
if value.mac_value:
mk_elem(element, 'pskc:ValueMAC',
base64.b64encode(value.mac_value).decode())
@classmethod
def serialise_policy(cls, policy, key_elm):
# check if any policy attribute is set
if not policy.key_usage and all(x is None for x in (
policy.start_date, policy.expiry_date,
policy.number_of_transactions, policy.pin_key_id,
policy.pin_usage, policy.pin_max_failed_attempts,
policy.pin_min_length, policy.pin_max_length,
policy.pin_encoding)):
return
policy_elm = mk_elem(key_elm, 'pskc:Policy', empty=True)
mk_elem(policy_elm, 'pskc:StartDate', policy.start_date)
mk_elem(policy_elm, 'pskc:ExpiryDate', policy.expiry_date)
mk_elem(policy_elm, 'pskc:PINPolicy',
PINKeyId=policy.pin_key_id,
PINUsageMode=policy.pin_usage,
MaxFailedAttempts=policy.pin_max_failed_attempts,
MinLength=policy.pin_min_length,
MaxLength=policy.pin_max_length,
PINEncoding=policy.pin_encoding)
for usage in policy.key_usage:
mk_elem(policy_elm, 'pskc:KeyUsage', usage)
mk_elem(policy_elm, 'pskc:NumberOfTransactions',
policy.number_of_transactions)
@classmethod
def serialise_signature(cls, signature, container):
if not signature.key:
return container
# move the namespace to the root element and reformat before signing
mk_elem(container, 'ds:Signature', Id='placeholder')
container = move_namespaces(container)
reformat(container)
# sign the document
return signature.sign_xml(container)
|