summaryrefslogtreecommitdiff
path: root/src/leap/keymanager/openpgp.py
blob: 0f1629695460a074ca3fc95e436c992eee344da8 (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
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
# -*- coding: utf-8 -*-
# openpgp.py
# Copyright (C) 2013-2015 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/>.
"""
Infrastructure for using OpenPGP keys in Key Manager.
"""
import logging
import os
import re
import shutil
import tempfile
import io


from datetime import datetime
from multiprocessing import cpu_count
from gnupg import GPG
from gnupg.gnupg import GPGUtilities
from twisted.internet import defer
from twisted.internet.threads import deferToThread

from leap.common.check import leap_assert, leap_assert_type, leap_check
from leap.keymanager import errors
from leap.keymanager.keys import (
    EncryptionKey,
    EncryptionScheme,
    is_address,
    build_key_from_dict,
    TYPE_FINGERPRINT_PRIVATE_INDEX,
    TYPE_ADDRESS_PRIVATE_INDEX,
    KEY_ADDRESS_KEY,
    KEY_FINGERPRINT_KEY,
    KEYMANAGER_ACTIVE_TYPE,
)


logger = logging.getLogger(__name__)


#
# A temporary GPG keyring wrapped to provide OpenPGP functionality.
#

# This function will be used to call blocking GPG functions outside
# of Twisted reactor and match the concurrent calls to the amount of CPU cores
cpu_core_semaphore = defer.DeferredSemaphore(cpu_count())


def from_thread(func, *args, **kwargs):
    call = lambda: deferToThread(func, *args, **kwargs)
    return cpu_core_semaphore.run(call)


class TempGPGWrapper(object):
    """
    A context manager that wraps a temporary GPG keyring which only contains
    the keys given at object creation.
    """

    def __init__(self, keys=None, gpgbinary=None):
        """
        Create an empty temporary keyring and import any given C{keys} into
        it.

        :param keys: OpenPGP key, or list of.
        :type keys: OpenPGPKey or list of OpenPGPKeys
        :param gpgbinary: Name for GnuPG binary executable.
        :type gpgbinary: C{str}
        """
        self._gpg = None
        self._gpgbinary = gpgbinary
        if not keys:
            keys = list()
        if not isinstance(keys, list):
            keys = [keys]
        self._keys = keys
        for key in keys:
            leap_assert_type(key, OpenPGPKey)

    def __enter__(self):
        """
        Build and return a GPG keyring containing the keys given on
        object creation.

        :return: A GPG instance containing the keys given on object creation.
        :rtype: gnupg.GPG
        """
        self._build_keyring()
        return self._gpg

    def __exit__(self, exc_type, exc_value, traceback):
        """
        Ensure the gpg is properly destroyed.
        """
        # TODO handle exceptions and log here
        self._destroy_keyring()

    def _build_keyring(self):
        """
        Create a GPG keyring containing the keys given on object creation.

        :return: A GPG instance containing the keys given on object creation.
        :rtype: gnupg.GPG
        """
        privkeys = [key for key in self._keys if key and key.private is True]
        publkeys = [key for key in self._keys if key and key.private is False]
        # here we filter out public keys that have a correspondent
        # private key in the list because the private key_data by
        # itself is enough to also have the public key in the keyring,
        # and we want to count the keys afterwards.

        privfps = map(lambda privkey: privkey.fingerprint, privkeys)
        publkeys = filter(
            lambda pubkey: pubkey.fingerprint not in privfps, publkeys)

        listkeys = lambda: self._gpg.list_keys()
        listsecretkeys = lambda: self._gpg.list_keys(secret=True)

        self._gpg = GPG(binary=self._gpgbinary,
                        homedir=tempfile.mkdtemp())
        leap_assert(len(listkeys()) is 0, 'Keyring not empty.')

        # import keys into the keyring:
        # concatenating ascii-armored keys, which is correctly
        # understood by GPG.

        self._gpg.import_keys("".join(
            [x.key_data for x in publkeys + privkeys]))

        # assert the number of keys in the keyring
        leap_assert(
            len(listkeys()) == len(publkeys) + len(privkeys),
            'Wrong number of public keys in keyring: %d, should be %d)' %
            (len(listkeys()), len(publkeys) + len(privkeys)))
        leap_assert(
            len(listsecretkeys()) == len(privkeys),
            'Wrong number of private keys in keyring: %d, should be %d)' %
            (len(listsecretkeys()), len(privkeys)))

    def _destroy_keyring(self):
        """
        Securely erase the keyring.
        """
        # TODO: implement some kind of wiping of data or a more
        # secure way that
        # does not write to disk.

        try:
            for secret in [True, False]:
                for key in self._gpg.list_keys(secret=secret):
                    self._gpg.delete_keys(
                        key['fingerprint'],
                        secret=secret)
            leap_assert(len(self._gpg.list_keys()) is 0, 'Keyring not empty!')

        except:
            raise

        finally:
            leap_assert(self._gpg.homedir != os.path.expanduser('~/.gnupg'),
                        "watch out! Tried to remove default gnupg home!")
            shutil.rmtree(self._gpg.homedir)


def _parse_address(address):
    """
    Remove name, '<', '>' and the identity suffix after the '+' until the '@'
    e.g.: test_user+something@provider.com becomes test_user@provider.com
    since the key belongs to the identity without the '+' suffix.

    :type address: str
    :rtype: str
    """
    mail_regex = '(.*<)?([\w.-]+)(\+.*)?(@[\w.-]+)(>.*)?'
    match = re.match(mail_regex, address)
    if match is None:
        return None
    return ''.join(match.group(2, 4))


#
# The OpenPGP wrapper
#

class OpenPGPKey(EncryptionKey):
    """
    Base class for OpenPGP keys.
    """

    def __init__(self, address, gpgbinary=None, **kwargs):
        self._gpgbinary = gpgbinary
        super(OpenPGPKey, self).__init__(address, **kwargs)

    @property
    def signatures(self):
        """
        Get the key signatures

        :return: the key IDs that have signed the key
        :rtype: list(str)
        """
        with TempGPGWrapper(keys=[self], gpgbinary=self._gpgbinary) as gpg:
            res = gpg.list_sigs(self.fingerprint)
            for uid, sigs in res.sigs.iteritems():
                if _parse_address(uid) in self.address:
                    return sigs

        return []

    def merge(self, newkey):
        if newkey.fingerprint != self.fingerprint:
            logger.critical(
                "Can't put a key whith the same key_id and different "
                "fingerprint: %s, %s"
                % (newkey.fingerprint, self.fingerprint))
            raise errors.KeyFingerprintMismatch(newkey.fingerprint)

        with TempGPGWrapper(gpgbinary=self._gpgbinary) as gpg:
            gpg.import_keys(self.key_data)
            gpg.import_keys(newkey.key_data)
            gpgkey = gpg.list_keys(secret=newkey.private).pop()

            if gpgkey['expires']:
                self.expiry_date = datetime.fromtimestamp(
                    int(gpgkey['expires']))
            else:
                self.expiry_date = None

            self.uids = []
            for uid in gpgkey['uids']:
                self.uids.append(_parse_address(uid))

            self.length = int(gpgkey['length'])
            self.key_data = gpg.export_keys(gpgkey['fingerprint'],
                                            secret=self.private)

        if newkey.validation > self.validation:
            self.validation = newkey.validation
        if newkey.last_audited_at > self.last_audited_at:
            self.validation = newkey.last_audited_at
        self.encr_used = newkey.encr_used or self.encr_used
        self.sign_used = newkey.sign_used or self.sign_used
        self.refreshed_at = datetime.now()


class OpenPGPScheme(EncryptionScheme):
    """
    A wrapper for OpenPGP keys management and use (encryption, decyption,
    signing and verification).
    """

    # type used on the soledad documents
    KEY_TYPE = OpenPGPKey.__name__
    ACTIVE_TYPE = KEY_TYPE + KEYMANAGER_ACTIVE_TYPE

    def __init__(self, soledad, gpgbinary=None):
        """
        Initialize the OpenPGP wrapper.

        :param soledad: A Soledad instance for key storage.
        :type soledad: leap.soledad.Soledad
        :param gpgbinary: Name for GnuPG binary executable.
        :type gpgbinary: C{str}
        """
        EncryptionScheme.__init__(self, soledad)
        self._wait_indexes("get_key", "put_key")
        self._gpgbinary = gpgbinary

    #
    # Keys management
    #

    def gen_key(self, address):
        """
        Generate an OpenPGP keypair bound to C{address}.

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

        :return: A Deferred which fires with the key bound to address, or fails
                 with KeyAlreadyExists if key already exists in local database.
        :rtype: Deferred
        """
        # make sure the key does not already exist
        leap_assert(is_address(address), 'Not an user address: %s' % address)

        @defer.inlineCallbacks
        def _gen_key(_):
            with TempGPGWrapper(gpgbinary=self._gpgbinary) as gpg:
                # TODO: inspect result, or use decorator
                params = gpg.gen_key_input(
                    key_type='RSA',
                    key_length=4096,
                    name_real=address,
                    name_email=address,
                    name_comment='')
                logger.info("About to generate keys... "
                            "This might take SOME time.")
                yield from_thread(gpg.gen_key, params)
                logger.info("Keys for %s have been successfully "
                            "generated." % (address,))
                pubkeys = gpg.list_keys()

                # assert for new key characteristics
                leap_assert(
                    len(pubkeys) is 1,  # a unitary keyring!
                    'Keyring has wrong number of keys: %d.' % len(pubkeys))
                key = gpg.list_keys(secret=True).pop()
                leap_assert(
                    len(key['uids']) is 1,  # with just one uid!
                    'Wrong number of uids for key: %d.' % len(key['uids']))
                uid_match = False
                for uid in key['uids']:
                    if re.match('.*<%s>$' % address, uid) is not None:
                        uid_match = True
                        break
                leap_assert(uid_match, 'Key not correctly bound to address.')

                # insert both public and private keys in storage
                deferreds = []
                for secret in [True, False]:
                    key = gpg.list_keys(secret=secret).pop()
                    openpgp_key = self._build_key_from_gpg(
                        key,
                        gpg.export_keys(key['fingerprint'], secret=secret))
                    d = self.put_key(openpgp_key, address)
                    deferreds.append(d)
                yield defer.gatherResults(deferreds)

        def key_already_exists(_):
            raise errors.KeyAlreadyExists(address)

        d = self.get_key(address)
        d.addCallbacks(key_already_exists, _gen_key)
        d.addCallback(lambda _: self.get_key(address, private=True))
        return d

    def get_key(self, address, private=False):
        """
        Get key bound to C{address} 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: A Deferred which fires with the OpenPGPKey bound to address,
                 or which fails with KeyNotFound if the key was not found on
                 local storage.
        :rtype: Deferred
        """
        address = _parse_address(address)

        def build_key((keydoc, activedoc)):
            if keydoc is None:
                raise errors.KeyNotFound(address)
            leap_assert(
                address in keydoc.content[KEY_ADDRESS_KEY],
                'Wrong address in key %s. Expected %s, found %s.'
                % (keydoc.content[KEY_FINGERPRINT_KEY], address,
                   keydoc.content[KEY_ADDRESS_KEY]))
            key = build_key_from_dict(OpenPGPKey, keydoc.content,
                                      activedoc.content)
            key._gpgbinary = self._gpgbinary
            return key

        d = self._get_key_doc(address, private)
        d.addCallback(build_key)
        return d

    def parse_ascii_key(self, key_data):
        """
        Parses an ascii armored key (or key pair) data and returns
        the OpenPGPKey keys.

        :param key_data: the key data to be parsed.
        :type key_data: str or unicode

        :returns: the public key and private key (if applies) for that data.
        :rtype: (public, private) -> tuple(OpenPGPKey, OpenPGPKey)
                the tuple may have one or both components None
        """
        leap_assert_type(key_data, (str, unicode))
        # TODO: add more checks for correct key data.
        leap_assert(key_data is not None, 'Data does not represent a key.')

        priv_info, privkey = process_ascii_key(
            key_data, self._gpgbinary, secret=True)
        pub_info, pubkey = process_ascii_key(
            key_data, self._gpgbinary, secret=False)

        if not pubkey:
            return (None, None)

        openpgp_privkey = None
        if privkey:
            # build private key
            openpgp_privkey = self._build_key_from_gpg(priv_info, privkey)
            leap_check(pub_info['fingerprint'] == priv_info['fingerprint'],
                       'Fingerprints for public and private key differ.',
                       errors.KeyFingerprintMismatch)
        # build public key
        openpgp_pubkey = self._build_key_from_gpg(pub_info, pubkey)

        return (openpgp_pubkey, openpgp_privkey)

    def put_ascii_key(self, key_data, address):
        """
        Put key contained in ascii-armored C{key_data} in local storage.

        :param key_data: The key data to be stored.
        :type key_data: str or unicode
        :param address: address for which this key will be active
        :type address: str

        :return: A Deferred which fires when the OpenPGPKey is in the storage.
        :rtype: Deferred
        """
        leap_assert_type(key_data, (str, unicode))

        openpgp_privkey = None
        try:
            openpgp_pubkey, openpgp_privkey = self.parse_ascii_key(key_data)
        except (errors.KeyAddressMismatch, errors.KeyFingerprintMismatch) as e:
            return defer.fail(e)

        def put_key(_, key):
            return self.put_key(key, address)

        d = defer.succeed(None)
        if openpgp_pubkey is not None:
            d.addCallback(put_key, openpgp_pubkey)
        if openpgp_privkey is not None:
            d.addCallback(put_key, openpgp_privkey)
        return d

    def put_key(self, key, address):
        """
        Put C{key} in local storage.

        :param key: The key to be stored.
        :type key: OpenPGPKey
        :param address: address for which this key will be active.
        :type address: str

        :return: A Deferred which fires when the key is in the storage.
        :rtype: Deferred
        """
        def merge_and_put((keydoc, activedoc)):
            if not keydoc:
                return put_new_key(activedoc)

            active_content = None
            if activedoc:
                active_content = activedoc.content
            oldkey = build_key_from_dict(OpenPGPKey, keydoc.content,
                                         active_content)

            key.merge(oldkey)
            keydoc.set_json(key.get_json())
            deferred_key = self._soledad.put_doc(keydoc)

            active_json = key.get_active_json(address)
            if activedoc:
                activedoc.set_json(active_json)
                deferred_active = self._soledad.put_doc(activedoc)
            else:
                deferred_active = self._soledad.create_doc_from_json(
                    active_json)

            return defer.gatherResults([deferred_key, deferred_active])

        def put_new_key(activedoc):
            deferreds = []
            if activedoc:
                d = self._soledad.delete_doc(activedoc)
                deferreds.append(d)
            for json in [key.get_json(), key.get_active_json(address)]:
                d = self._soledad.create_doc_from_json(json)
                deferreds.append(d)
            return defer.gatherResults(deferreds)

        dk = self._get_key_doc_from_fingerprint(key.fingerprint, key.private)
        da = self._get_active_doc_from_address(address, key.private)
        d = defer.gatherResults([dk, da])
        d.addCallback(merge_and_put)
        return d

    def _get_key_doc(self, address, private=False):
        """
        Get the document with a key (public, by default) bound to C{address}.

        If C{private} is True, looks for a private key instead of a public.

        :param address: The address bound to the key.
        :type address: str
        :param private: Whether to look for a private key.
        :type private: bool

        :return: A Deferred which fires with a touple of two SoledadDocument
                 (keydoc, activedoc) or None if it does not exist.
        :rtype: Deferred
        """
        def get_key_from_active_doc(activedoc):
            if not activedoc:
                return (None, None)
            fingerprint = activedoc.content[KEY_FINGERPRINT_KEY]
            d = self._get_key_doc_from_fingerprint(fingerprint, private)
            d.addCallback(delete_active_if_no_key, activedoc)
            return d

        def delete_active_if_no_key(keydoc, activedoc):
            if not keydoc:
                d = self._soledad.delete_doc(activedoc)
                d.addCallback(lambda _: (None, None))
                return d
            return (keydoc, activedoc)

        d = self._get_active_doc_from_address(address, private)
        d.addCallback(get_key_from_active_doc)
        return d

    def _build_key_from_gpg(self, key, key_data):
        """
        Build an OpenPGPKey for C{address} based on C{key} from
        local gpg storage.

        ASCII armored GPG key data has to be queried independently in this
        wrapper, so we receive it in C{key_data}.

        :param key: Key obtained from GPG storage.
        :type key: dict
        :param key_data: Key data obtained from GPG storage.
        :type key_data: str
        :return: An instance of the key.
        :rtype: OpenPGPKey
        """
        return build_gpg_key(key, key_data, self._gpgbinary)

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

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

        :return: A Deferred which fires when the key is deleted, or which
                 fails with KeyNotFound if the key was not found on local
                 storage.
        :rtype: Deferred
        """
        leap_assert_type(key, OpenPGPKey)

        def delete_docs(activedocs):
            deferreds = []
            for doc in activedocs:
                d = self._soledad.delete_doc(doc)
                deferreds.append(d)
            return defer.gatherResults(deferreds)

        def get_key_docs(_):
            return self._soledad.get_from_index(
                TYPE_FINGERPRINT_PRIVATE_INDEX,
                self.KEY_TYPE,
                key.fingerprint,
                '1' if key.private else '0')

        def delete_key(docs):
            if len(docs) == 0:
                raise errors.KeyNotFound(key)
            elif len(docs) > 1:
                logger.warning("There is more than one key for fingerprint %s"
                               % key.fingerprint)

            has_deleted = False
            deferreds = []
            for doc in docs:
                if doc.content['fingerprint'] == key.fingerprint:
                    d = self._soledad.delete_doc(doc)
                    deferreds.append(d)
                    has_deleted = True
            if not has_deleted:
                raise errors.KeyNotFound(key)
            return defer.gatherResults(deferreds)

        d = self._soledad.get_from_index(
            TYPE_FINGERPRINT_PRIVATE_INDEX,
            self.ACTIVE_TYPE,
            key.fingerprint,
            '1' if key.private else '0')
        d.addCallback(delete_docs)
        d.addCallback(get_key_docs)
        d.addCallback(delete_key)
        return d

    #
    # Data encryption, decryption, signing and verifying
    #

    @staticmethod
    def _assert_gpg_result_ok(result):
        """
        Check if GPG result is 'ok' and log stderr outputs.

        :param result: GPG results, which have a field calld 'ok' that states
                       whether the gpg operation was successful or not.
        :type result: object

        :raise GPGError: Raised when the gpg operation was not successful.
        """
        stderr = getattr(result, 'stderr', None)
        if stderr:
            logger.debug("%s" % (stderr,))
        if getattr(result, 'ok', None) is not True:
            raise errors.GPGError(
                'Failed to encrypt/decrypt: %s' % stderr)

    @defer.inlineCallbacks
    def encrypt(self, data, pubkey, passphrase=None, sign=None,
                cipher_algo='AES256'):
        """
        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: OpenPGPKey
        :param sign: The key used for signing.
        :type sign: OpenPGPKey
        :param cipher_algo: The cipher algorithm to use.
        :type cipher_algo: str

        :return: A Deferred that will be fired with the encrypted data.
        :rtype: defer.Deferred

        :raise EncryptError: Raised if failed encrypting for some reason.
        """
        leap_assert_type(pubkey, OpenPGPKey)
        leap_assert(pubkey.private is False, 'Key is not public.')
        keys = [pubkey]
        if sign is not None:
            leap_assert_type(sign, OpenPGPKey)
            leap_assert(sign.private is True)
            keys.append(sign)
        with TempGPGWrapper(keys, self._gpgbinary) as gpg:
            result = yield from_thread(
                gpg.encrypt,
                data, pubkey.fingerprint,
                default_key=sign.fingerprint if sign else None,
                passphrase=passphrase, symmetric=False,
                cipher_algo=cipher_algo)
            # Here we cannot assert for correctness of sig because the sig is
            # in the ciphertext.
            # result.ok    - (bool) indicates if the operation succeeded
            # result.data  - (bool) contains the result of the operation
            try:
                self._assert_gpg_result_ok(result)
                defer.returnValue(result.data)
            except errors.GPGError as e:
                logger.error('Failed to decrypt: %s.' % str(e))
                raise errors.EncryptError()

    @defer.inlineCallbacks
    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 passphrase: The passphrase for the secret key used for
                           decryption.
        :type passphrase: str
        :param verify: The key used to verify a signature.
        :type verify: OpenPGPKey

        :return: Deferred that will fire with the decrypted data and
                 if signature verifies (unicode, bool)
        :rtype: Deferred

        :raise DecryptError: Raised if failed decrypting for some reason.
        """
        leap_assert(privkey.private is True, 'Key is not private.')
        keys = [privkey]
        if verify is not None:
            leap_assert_type(verify, OpenPGPKey)
            leap_assert(verify.private is False)
            keys.append(verify)
        with TempGPGWrapper(keys, self._gpgbinary) as gpg:
            try:
                result = yield from_thread(gpg.decrypt,
                                           data, passphrase=passphrase,
                                           always_trust=True)
                self._assert_gpg_result_ok(result)

                # verify signature
                sign_valid = False
                if (verify is not None and
                        result.valid is True and
                        verify.fingerprint == result.pubkey_fingerprint):
                    sign_valid = True

                defer.returnValue((result.data, sign_valid))
            except errors.GPGError as e:
                logger.error('Failed to decrypt: %s.' % str(e))
                raise errors.DecryptError(str(e))

    def is_encrypted(self, data):
        """
        Return whether C{data} was asymmetrically encrypted using OpenPGP.

        :param data: The data we want to know about.
        :type data: str

        :return: Whether C{data} was encrypted using this wrapper.
        :rtype: bool
        """
        with TempGPGWrapper(gpgbinary=self._gpgbinary) as gpg:
            gpgutil = GPGUtilities(gpg)
            return gpgutil.is_encrypted_asym(data)

    def sign(self, data, privkey, digest_algo='SHA512', clearsign=False,
             detach=True, binary=False):
        """
        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: OpenPGPKey
        :param digest_algo: The hash digest to use.
        :type digest_algo: str
        :param clearsign: If True, create a cleartext signature.
        :type clearsign: bool
        :param detach: If True, create a detached signature.
        :type detach: bool
        :param binary: If True, do not ascii armour the output.
        :type binary: bool

        :return: The ascii-armored signed data.
        :rtype: str
        """
        leap_assert_type(privkey, OpenPGPKey)
        leap_assert(privkey.private is True)

        # result.fingerprint - contains the fingerprint of the key used to
        #                      sign.
        with TempGPGWrapper(privkey, self._gpgbinary) as gpg:
            result = gpg.sign(data, default_key=privkey.fingerprint,
                              digest_algo=digest_algo, clearsign=clearsign,
                              detach=detach, binary=binary)
            rfprint = privkey.fingerprint
            privkey = gpg.list_keys(secret=True).pop()
            kfprint = privkey['fingerprint']
            if result.fingerprint is None:
                raise errors.SignFailed(
                    'Failed to sign with key %s: %s' %
                    (privkey['fingerprint'], result.stderr))
            leap_assert(
                result.fingerprint == kfprint,
                'Signature and private key fingerprints mismatch: '
                '%s != %s' % (rfprint, kfprint))
        return result.data

    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: OpenPGPKey
        :param detached_sig: A detached signature. If given, C{data} is
                             verified against this detached signature.
        :type detached_sig: str

        :return: signature matches
        :rtype: bool
        """
        leap_assert_type(pubkey, OpenPGPKey)
        leap_assert(pubkey.private is False)
        with TempGPGWrapper(pubkey, self._gpgbinary) as gpg:
            result = None
            if detached_sig is None:
                result = gpg.verify(data)
            else:
                # to verify using a detached sig we have to use
                # gpg.verify_file(), which receives the data as a binary
                # stream and the name of a file containing the signature.
                sf, sfname = tempfile.mkstemp()
                with os.fdopen(sf, 'w') as sfd:
                    sfd.write(detached_sig)
                result = gpg.verify_file(io.BytesIO(data), sig_file=sfname)
                os.unlink(sfname)
            gpgpubkey = gpg.list_keys().pop()
            valid = result.valid
            rfprint = result.fingerprint
            kfprint = gpgpubkey['fingerprint']
            return valid and rfprint == kfprint

    def _get_active_doc_from_address(self, address, private):
        d = self._soledad.get_from_index(
            TYPE_ADDRESS_PRIVATE_INDEX,
            self.ACTIVE_TYPE,
            address,
            '1' if private else '0')
        d.addCallback(self._repair_and_get_doc, self._repair_active_docs)
        return d

    def _get_key_doc_from_fingerprint(self, fingerprint, private):
        d = self._soledad.get_from_index(
            TYPE_FINGERPRINT_PRIVATE_INDEX,
            self.KEY_TYPE,
            fingerprint,
            '1' if private else '0')
        d.addCallback(self._repair_and_get_doc, self._repair_key_docs)
        return d

    def _repair_and_get_doc(self, doclist, repair_func):
        if len(doclist) is 0:
            return None
        elif len(doclist) > 1:
            return repair_func(doclist)
        return doclist[0]


def process_ascii_key(key_data, gpgbinary, secret=False):
    with TempGPGWrapper(gpgbinary=gpgbinary) as gpg:
        try:
            gpg.import_keys(key_data)
            info = gpg.list_keys(secret=secret).pop()
            key = gpg.export_keys(info['fingerprint'], secret=secret)
        except IndexError:
            info = {}
            key = None
    return info, key


def build_gpg_key(key_info, key_data, gpgbinary=None):
    expiry_date = None
    if key_info['expires']:
        expiry_date = datetime.fromtimestamp(int(key_info['expires']))
    address = []
    for uid in key_info['uids']:
        address.append(_parse_address(uid))

    return OpenPGPKey(
        address,
        gpgbinary=gpgbinary,
        fingerprint=key_info['fingerprint'],
        key_data=key_data,
        private=True if key_info['type'] == 'sec' else False,
        length=int(key_info['length']),
        expiry_date=expiry_date,
        refreshed_at=datetime.now())