summaryrefslogtreecommitdiff
path: root/src/leap/keymanager/keys.py
blob: b5c9118d74daeca2bb17adac526b7814b3fec44c (plain)
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
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
# -*- coding: utf-8 -*-
# keys.py
# Copyright (C) 2013 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.


"""
Abstact key type and encryption scheme representations.
"""


try:
    import simplejson as json
except ImportError:
    import json  # noqa
import logging
import re


from abc import ABCMeta, abstractmethod
from leap.common.check import leap_assert

from leap.keymanager.validation import ValidationLevel, toValidationLevel

logger = logging.getLogger(__name__)


#
# Dictionary keys used for storing cryptographic keys.
#

KEY_ADDRESS_KEY = 'address'
KEY_TYPE_KEY = 'type'
KEY_ID_KEY = 'key_id'
KEY_FINGERPRINT_KEY = 'fingerprint'
KEY_DATA_KEY = 'key_data'
KEY_PRIVATE_KEY = 'private'
KEY_LENGTH_KEY = 'length'
KEY_EXPIRY_DATE_KEY = 'expiry_date'
KEY_FIRST_SEEN_AT_KEY = 'first_seen_at'
KEY_LAST_AUDITED_AT_KEY = 'last_audited_at'
KEY_VALIDATION_KEY = 'validation'
KEY_TAGS_KEY = 'tags'


#
# Key storage constants
#

KEYMANAGER_KEY_TAG = 'keymanager-key'


#
# key indexing constants.
#

TAGS_PRIVATE_INDEX = 'by-tags-private'
TAGS_ADDRESS_PRIVATE_INDEX = 'by-tags-address-private'
INDEXES = {
    TAGS_PRIVATE_INDEX: [
        KEY_TAGS_KEY,
        'bool(%s)' % KEY_PRIVATE_KEY,
    ],
    TAGS_ADDRESS_PRIVATE_INDEX: [
        KEY_TAGS_KEY,
        KEY_ADDRESS_KEY,
        'bool(%s)' % KEY_PRIVATE_KEY,
    ]
}


#
# Key handling utilities
#

def is_address(address):
    """
    Return whether the given C{address} is in the form user@provider.

    :param address: The address to be tested.
    :type address: str
    :return: Whether C{address} is in the form user@provider.
    :rtype: bool
    """
    return bool(re.match('[\w.-]+@[\w.-]+', address))


def build_key_from_dict(kClass, address, kdict):
    """
    Build an C{kClass} key bound to C{address} based on info in C{kdict}.

    :param address: The address bound to the key.
    :type address: str
    :param kdict: Dictionary with key data.
    :type kdict: dict
    :return: An instance of the key.
    :rtype: C{kClass}
    """
    leap_assert(
        address == kdict[KEY_ADDRESS_KEY],
        'Wrong address in key data.')
    try:
        validation = toValidationLevel(kdict[KEY_VALIDATION_KEY])
    except ValueError:
        logger.error("Not valid validation level (%s) for key %s",
                     (kdict[KEY_VALIDATION_KEY], kdict[KEY_ID_KEY]))
        validation = ValidationLevel.Weak_Chain

    return kClass(
        address,
        key_id=kdict[KEY_ID_KEY],
        fingerprint=kdict[KEY_FINGERPRINT_KEY],
        key_data=kdict[KEY_DATA_KEY],
        private=kdict[KEY_PRIVATE_KEY],
        length=kdict[KEY_LENGTH_KEY],
        expiry_date=kdict[KEY_EXPIRY_DATE_KEY],
        first_seen_at=kdict[KEY_FIRST_SEEN_AT_KEY],
        last_audited_at=kdict[KEY_LAST_AUDITED_AT_KEY],
        validation=validation,
    )


#
# Abstraction for encryption keys
#

class EncryptionKey(object):
    """
    Abstract class for encryption keys.

    A key is "validated" if the nicknym agent has bound the user address to a
    public key.
    """

    __metaclass__ = ABCMeta

    def __init__(self, address, key_id=None, fingerprint=None,
                 key_data=None, private=None, length=None, expiry_date=None,
                 validation=None, first_seen_at=None, last_audited_at=None):
        self.address = address
        self.key_id = key_id
        self.fingerprint = fingerprint
        self.key_data = key_data
        self.private = private
        self.length = length
        self.expiry_date = expiry_date
        self.validation = validation
        self.first_seen_at = first_seen_at
        self.last_audited_at = last_audited_at

    def get_json(self):
        """
        Return a JSON string describing this key.

        :return: The JSON string describing this key.
        :rtype: str
        """
        return json.dumps({
            KEY_ADDRESS_KEY: self.address,
            KEY_TYPE_KEY: str(self.__class__),
            KEY_ID_KEY: self.key_id,
            KEY_FINGERPRINT_KEY: self.fingerprint,
            KEY_DATA_KEY: self.key_data,
            KEY_PRIVATE_KEY: self.private,
            KEY_LENGTH_KEY: self.length,
            KEY_EXPIRY_DATE_KEY: self.expiry_date,
            KEY_VALIDATION_KEY: str(self.validation),
            KEY_FIRST_SEEN_AT_KEY: self.first_seen_at,
            KEY_LAST_AUDITED_AT_KEY: self.last_audited_at,
            KEY_TAGS_KEY: [KEYMANAGER_KEY_TAG],
        })

    def __repr__(self):
        """
        Representation of this class
        """
        return u"<%s 0x%s (%s - %s)>" % (
            self.__class__.__name__,
            self.key_id,
            self.address,
            "priv" if self.private else "publ")


#
# Encryption schemes
#

class EncryptionScheme(object):
    """
    Abstract class for Encryption Schemes.

    A wrapper for a certain encryption schemes should know how to get and put
    keys in local storage using Soledad, how to generate new keys and how to
    find out about possibly encrypted content.
    """

    __metaclass__ = ABCMeta

    def __init__(self, soledad):
        """
        Initialize this Encryption Scheme.

        :param soledad: A Soledad instance for local storage of keys.
        :type soledad: leap.soledad.Soledad
        """
        self._soledad = soledad
        self._init_indexes()

    def _init_indexes(self):
        """
        Initialize the database indexes.
        """
        leap_assert(self._soledad is not None,
                    "Cannot init indexes with null soledad")
        # Ask the database for currently existing indexes.
        db_indexes = dict(self._soledad.list_indexes())
        # Loop through the indexes we expect to find.
        for name, expression in INDEXES.items():
            if name not in db_indexes:
                # The index does not yet exist.
                self._soledad.create_index(name, *expression)
                continue
            if expression == db_indexes[name]:
                # The index exists and is up to date.
                continue
            # The index exists but the definition is not what expected, so we
            # delete it and add the proper index expression.
            self._soledad.delete_index(name)
            self._soledad.create_index(name, *expression)

    @abstractmethod
    def get_key(self, address, private=False):
        """
        Get key from local storage.

        :param address: The address bound to the key.
        :type address: str
        :param private: Look for a private key instead of a public one?
        :type private: bool

        :return: The key bound to C{address}.
        :rtype: EncryptionKey
        @raise KeyNotFound: If the key was not found on local storage.
        """
        pass

    @abstractmethod
    def put_key(self, key):
        """
        Put a key in local storage.

        :param key: The key to be stored.
        :type key: EncryptionKey
        """
        pass

    @abstractmethod
    def gen_key(self, address):
        """
        Generate a new key.

        :param address: The address bound to the key.
        :type address: str

        :return: The key bound to C{address}.
        :rtype: EncryptionKey
        """
        pass

    @abstractmethod
    def delete_key(self, key):
        """
        Remove C{key} from storage.

        :param key: The key to be removed.
        :type key: EncryptionKey
        """
        pass

    @abstractmethod
    def encrypt(self, data, pubkey, passphrase=None, sign=None):
        """
        Encrypt C{data} using public @{pubkey} and sign with C{sign} key.

        :param data: The data to be encrypted.
        :type data: str
        :param pubkey: The key used to encrypt.
        :type pubkey: EncryptionKey
        :param sign: The key used for signing.
        :type sign: EncryptionKey

        :return: The encrypted data.
        :rtype: str
        """
        pass

    @abstractmethod
    def decrypt(self, data, privkey, passphrase=None, verify=None):
        """
        Decrypt C{data} using private @{privkey} and verify with C{verify} key.

        :param data: The data to be decrypted.
        :type data: str
        :param privkey: The key used to decrypt.
        :type privkey: OpenPGPKey
        :param verify: The key used to verify a signature.
        :type verify: OpenPGPKey

        :return: The decrypted data.
        :rtype: str

        @raise InvalidSignature: Raised if unable to verify the signature with
            C{verify} key.
        """
        pass

    @abstractmethod
    def sign(self, data, privkey):
        """
        Sign C{data} with C{privkey}.

        :param data: The data to be signed.
        :type data: str

        :param privkey: The private key to be used to sign.
        :type privkey: EncryptionKey

        :return: The signed data.
        :rtype: str
        """
        pass

    @abstractmethod
    def verify(self, data, pubkey, detached_sig=None):
        """
        Verify signed C{data} with C{pubkey}, eventually using
        C{detached_sig}.

        :param data: The data to be verified.
        :type data: str
        :param pubkey: The public key to be used on verification.
        :type pubkey: EncryptionKey
        :param detached_sig: A detached signature. If given, C{data} is
                             verified against this sdetached signature.
        :type detached_sig: str

        :return: The signed data.
        :rtype: str
        """
        pass