olm.cpp 21.7 KB
Newer Older
Mark Haines's avatar
Mark Haines committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
/* Copyright 2015 OpenMarket Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
Richard van der Hoff's avatar
Richard van der Hoff committed
15
#include "olm/olm.h"
16
17
#include "olm/session.hh"
#include "olm/account.hh"
18
#include "olm/cipher.h"
19
#include "olm/utility.hh"
20
#include "olm/base64.hh"
21
#include "olm/memory.hh"
22
23
24
25
26
27

#include <new>
#include <cstring>

namespace {

28
29
static OlmAccount * to_c(olm::Account * account) {
    return reinterpret_cast<OlmAccount *>(account);
30
31
}

32
33
34
35
36
37
static OlmSession * to_c(olm::Session * session) {
    return reinterpret_cast<OlmSession *>(session);
}

static OlmUtility * to_c(olm::Utility * utility) {
    return reinterpret_cast<OlmUtility *>(utility);
38
39
}

40
41
static olm::Account * from_c(OlmAccount * account) {
    return reinterpret_cast<olm::Account *>(account);
42
43
}

44
45
46
47
48
49
static olm::Session * from_c(OlmSession * session) {
    return reinterpret_cast<olm::Session *>(session);
}

static olm::Utility * from_c(OlmUtility * utility) {
    return reinterpret_cast<olm::Utility *>(utility);
50
51
52
53
54
55
56
57
58
59
}

static std::uint8_t * from_c(void * bytes) {
    return reinterpret_cast<std::uint8_t *>(bytes);
}

static std::uint8_t const * from_c(void const * bytes) {
    return reinterpret_cast<std::uint8_t const *>(bytes);
}

60
61
static const struct _olm_cipher_aes_sha_256 PICKLE_CIPHER =
    OLM_CIPHER_INIT_AES_SHA_256("Pickle");
62
63
64
65

std::size_t enc_output_length(
    size_t raw_length
) {
66
    auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
67
68
    std::size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
    length += cipher->ops->mac_length(cipher);
69
    return olm::encode_base64_length(length);
70
71
72
73
74
75
76
}


std::uint8_t * enc_output_pos(
    std::uint8_t * output,
    size_t raw_length
) {
77
    auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
78
79
    std::size_t length = cipher->ops->encrypt_ciphertext_length(cipher, raw_length);
    length += cipher->ops->mac_length(cipher);
80
    return output + olm::encode_base64_length(length) - length;
81
82
83
84
85
86
}

std::size_t enc_output(
    std::uint8_t const * key, std::size_t key_length,
    std::uint8_t * output, size_t raw_length
) {
87
    auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
88
89
    std::size_t ciphertext_length = cipher->ops->encrypt_ciphertext_length(
        cipher, raw_length
90
    );
91
    std::size_t length = ciphertext_length + cipher->ops->mac_length(cipher);
92
    std::size_t base64_length = olm::encode_base64_length(length);
93
    std::uint8_t * raw_output = output + base64_length - length;
94
95
    cipher->ops->encrypt(
        cipher,
96
97
98
99
100
        key, key_length,
        raw_output, raw_length,
        raw_output, ciphertext_length,
        raw_output, length
    );
101
    olm::encode_base64(raw_output, length, output);
102
103
104
105
106
107
    return raw_length;
}

std::size_t enc_input(
    std::uint8_t const * key, std::size_t key_length,
    std::uint8_t * input, size_t b64_length,
108
    OlmErrorCode & last_error
109
) {
110
    std::size_t enc_length = olm::decode_base64_length(b64_length);
111
    if (enc_length == std::size_t(-1)) {
112
        last_error = OlmErrorCode::OLM_INVALID_BASE64;
113
114
        return std::size_t(-1);
    }
115
    olm::decode_base64(input, b64_length, input);
116
    auto *cipher = OLM_CIPHER_BASE(&PICKLE_CIPHER);
117
118
119
    std::size_t raw_length = enc_length - cipher->ops->mac_length(cipher);
    std::size_t result = cipher->ops->decrypt(
        cipher,
120
121
122
123
124
125
        key, key_length,
        input, enc_length,
        input, raw_length,
        input, raw_length
    );
    if (result == std::size_t(-1)) {
126
        last_error = OlmErrorCode::OLM_BAD_ACCOUNT_KEY;
127
128
129
130
131
132
133
134
    }
    return result;
}


std::size_t b64_output_length(
    size_t raw_length
) {
135
    return olm::encode_base64_length(raw_length);
136
137
138
139
140
141
}

std::uint8_t * b64_output_pos(
    std::uint8_t * output,
    size_t raw_length
) {
142
    return output + olm::encode_base64_length(raw_length) - raw_length;
143
144
145
146
147
}

std::size_t b64_output(
    std::uint8_t * output, size_t raw_length
) {
148
    std::size_t base64_length = olm::encode_base64_length(raw_length);
149
    std::uint8_t * raw_output = output + base64_length - raw_length;
150
    olm::encode_base64(raw_output, raw_length, output);
151
152
153
154
155
    return base64_length;
}

std::size_t b64_input(
    std::uint8_t * input, size_t b64_length,
156
    OlmErrorCode & last_error
157
) {
158
    std::size_t raw_length = olm::decode_base64_length(b64_length);
159
    if (raw_length == std::size_t(-1)) {
160
        last_error = OlmErrorCode::OLM_INVALID_BASE64;
161
162
        return std::size_t(-1);
    }
163
    olm::decode_base64(input, b64_length, input);
164
165
166
167
168
169
170
171
172
    return raw_length;
}

} // namespace


extern "C" {


173
size_t olm_error() {
174
175
176
177
    return std::size_t(-1);
}


178
const char * olm_account_last_error(
179
    OlmAccount * account
180
) {
181
182
    auto error = from_c(account)->last_error;
    return _olm_error_to_string(error);
183
184
185
}


186
187
const char * olm_session_last_error(
    OlmSession * session
188
) {
189
190
    auto error = from_c(session)->last_error;
    return _olm_error_to_string(error);
191
192
}

193
194
195
const char * olm_utility_last_error(
    OlmUtility * utility
) {
196
197
    auto error = from_c(utility)->last_error;
    return _olm_error_to_string(error);
198
}
199

200
201
size_t olm_account_size() {
    return sizeof(olm::Account);
202
203
204
}


205
206
size_t olm_session_size() {
    return sizeof(olm::Session);
207
208
}

209
210
211
size_t olm_utility_size() {
    return sizeof(olm::Utility);
}
212

213
OlmAccount * olm_account(
214
215
    void * memory
) {
216
    olm::unset(memory, sizeof(olm::Account));
217
    return to_c(new(memory) olm::Account());
218
219
220
}


221
OlmSession * olm_session(
222
223
    void * memory
) {
224
    olm::unset(memory, sizeof(olm::Session));
225
    return to_c(new(memory) olm::Session());
226
227
228
}


229
230
231
232
233
234
235
236
OlmUtility * olm_utility(
    void * memory
) {
    olm::unset(memory, sizeof(olm::Utility));
    return to_c(new(memory) olm::Utility());
}


237
size_t olm_clear_account(
238
    OlmAccount * account
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
) {
    /* Clear the memory backing the account  */
    olm::unset(account, sizeof(olm::Account));
    /* Initialise a fresh account object in case someone tries to use it */
    new(account) olm::Account();
    return sizeof(olm::Account);
}


size_t olm_clear_session(
    OlmSession * session
) {
    /* Clear the memory backing the session */
    olm::unset(session, sizeof(olm::Session));
    /* Initialise a fresh session object in case someone tries to use it */
    new(session) olm::Session();
    return sizeof(olm::Session);
}


259
260
261
262
263
264
265
266
267
268
269
size_t olm_clear_utility(
    OlmUtility * utility
) {
    /* Clear the memory backing the session */
    olm::unset(utility, sizeof(olm::Utility));
    /* Initialise a fresh session object in case someone tries to use it */
    new(utility) olm::Utility();
    return sizeof(olm::Utility);
}


270
271
size_t olm_pickle_account_length(
    OlmAccount * account
272
273
274
275
276
) {
    return enc_output_length(pickle_length(*from_c(account)));
}


277
278
size_t olm_pickle_session_length(
    OlmSession * session
279
280
281
282
283
) {
    return enc_output_length(pickle_length(*from_c(session)));
}


284
285
size_t olm_pickle_account(
    OlmAccount * account,
286
287
288
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
) {
289
    olm::Account & object = *from_c(account);
290
291
    std::size_t raw_length = pickle_length(object);
    if (pickled_length < enc_output_length(raw_length)) {
292
        object.last_error = OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
293
294
295
296
297
298
299
        return size_t(-1);
    }
    pickle(enc_output_pos(from_c(pickled), raw_length), object);
    return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}


300
301
size_t olm_pickle_session(
    OlmSession * session,
302
303
304
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
) {
305
    olm::Session & object = *from_c(session);
306
307
    std::size_t raw_length = pickle_length(object);
    if (pickled_length < enc_output_length(raw_length)) {
308
        object.last_error = OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
309
310
311
312
313
314
315
        return size_t(-1);
    }
    pickle(enc_output_pos(from_c(pickled), raw_length), object);
    return enc_output(from_c(key), key_length, from_c(pickled), raw_length);
}


316
317
size_t olm_unpickle_account(
    OlmAccount * account,
318
319
320
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
) {
321
    olm::Account & object = *from_c(account);
322
323
324
325
326
327
328
329
    std::uint8_t * const pos = from_c(pickled);
    std::size_t raw_length = enc_input(
        from_c(key), key_length, pos, pickled_length, object.last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    std::uint8_t * const end = pos + raw_length;
330
331
332
333
334
    /* On success unpickle will return (pos + raw_length). If unpickling
     * terminates too soon then it will return a pointer before
     * (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
     */
    if (end != unpickle(pos, end + 1, object)) {
335
336
        if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
            object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
337
338
339
        }
        return std::size_t(-1);
    }
340
341
342
343
    return pickled_length;
}


344
345
size_t olm_unpickle_session(
    OlmSession * session,
346
347
348
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
) {
349
    olm::Session & object = *from_c(session);
350
351
352
353
354
355
356
    std::uint8_t * const pos = from_c(pickled);
    std::size_t raw_length = enc_input(
        from_c(key), key_length, pos, pickled_length, object.last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
357

358
    std::uint8_t * const end = pos + raw_length;
359
360
361
362
363
    /* On success unpickle will return (pos + raw_length). If unpickling
     * terminates too soon then it will return a pointer before
     * (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
     */
    if (end != unpickle(pos, end + 1, object)) {
364
365
        if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
            object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
366
367
368
        }
        return std::size_t(-1);
    }
369
370
371
372
    return pickled_length;
}


373
374
size_t olm_create_account_random_length(
    OlmAccount * account
375
376
377
378
379
) {
    return from_c(account)->new_account_random_length();
}


380
381
size_t olm_create_account(
    OlmAccount * account,
382
    void * random, size_t random_length
383
) {
384
385
386
    size_t result = from_c(account)->new_account(from_c(random), random_length);
    olm::unset(random, random_length);
    return result;
387
388
}

389

390
size_t olm_account_identity_keys_length(
391
392
393
    OlmAccount * account
) {
    return from_c(account)->get_identity_json_length();
394
395
}

396

397
398
size_t olm_account_identity_keys(
    OlmAccount * account,
399
400
    void * identity_keys, size_t identity_key_length
) {
401
402
403
    return from_c(account)->get_identity_json(
        from_c(identity_keys), identity_key_length
    );
404
405
406
}


407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
size_t olm_account_signature_length(
    OlmAccount * account
) {
    return b64_output_length(from_c(account)->signature_length());
}


size_t olm_account_sign(
    OlmAccount * account,
    void const * message, size_t message_length,
    void * signature, size_t signature_length
) {
    std::size_t raw_length = from_c(account)->signature_length();
    if (signature_length < b64_output_length(raw_length)) {
        from_c(account)->last_error =
422
            OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
423
424
425
426
427
428
429
430
431
432
        return std::size_t(-1);
    }
    from_c(account)->sign(
         from_c(message), message_length,
         b64_output_pos(from_c(signature), raw_length), raw_length
    );
    return b64_output(from_c(signature), raw_length);
}


433
434
size_t olm_account_one_time_keys_length(
    OlmAccount * account
435
) {
436
    return from_c(account)->get_one_time_keys_json_length();
437
438
439
}


440
441
size_t olm_account_one_time_keys(
    OlmAccount * account,
442
    void * one_time_keys_json, size_t one_time_key_json_length
443
) {
444
445
446
    return from_c(account)->get_one_time_keys_json(
        from_c(one_time_keys_json), one_time_key_json_length
    );
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
size_t olm_account_mark_keys_as_published(
    OlmAccount * account
) {
    return from_c(account)->mark_keys_as_published();
}


size_t olm_account_max_number_of_one_time_keys(
    OlmAccount * account
) {
    return from_c(account)->max_number_of_one_time_keys();
}


size_t olm_account_generate_one_time_keys_random_length(
    OlmAccount * account,
    size_t number_of_keys
) {
    return from_c(account)->generate_one_time_keys_random_length(number_of_keys);
}


size_t olm_account_generate_one_time_keys(
    OlmAccount * account,
    size_t number_of_keys,
475
    void * random, size_t random_length
476
) {
477
    size_t result = from_c(account)->generate_one_time_keys(
478
479
480
        number_of_keys,
        from_c(random), random_length
    );
481
482
    olm::unset(random, random_length);
    return result;
483
484
485
}


486
487
size_t olm_create_outbound_session_random_length(
    OlmSession * session
Mark Haines's avatar
Mark Haines committed
488
489
490
491
) {
    return from_c(session)->new_outbound_session_random_length();
}

492

493
494
495
size_t olm_create_outbound_session(
    OlmSession * session,
    OlmAccount * account,
496
497
    void const * their_identity_key, size_t their_identity_key_length,
    void const * their_one_time_key, size_t their_one_time_key_length,
498
    void * random, size_t random_length
499
) {
500
501
502
503
504
505
506
    std::uint8_t const * id_key = from_c(their_identity_key);
    std::uint8_t const * ot_key = from_c(their_one_time_key);
    std::size_t id_key_length = their_identity_key_length;
    std::size_t ot_key_length = their_one_time_key_length;

    if (olm::decode_base64_length(id_key_length) != olm::KEY_LENGTH
            || olm::decode_base64_length(ot_key_length) != olm::KEY_LENGTH
507
    ) {
508
        from_c(session)->last_error = OlmErrorCode::OLM_INVALID_BASE64;
509
510
        return std::size_t(-1);
    }
511
    olm::Curve25519PublicKey identity_key;
512
    olm::Curve25519PublicKey one_time_key;
513

514
515
    olm::decode_base64(id_key, id_key_length, identity_key.public_key);
    olm::decode_base64(ot_key, ot_key_length, one_time_key.public_key);
516

517
    size_t result = from_c(session)->new_outbound_session(
518
519
520
        *from_c(account), identity_key, one_time_key,
        from_c(random), random_length
    );
521
522
    olm::unset(random, random_length);
    return result;
523
524
525
}


526
527
528
size_t olm_create_inbound_session(
    OlmSession * session,
    OlmAccount * account,
529
530
531
532
533
534
535
536
537
    void * one_time_key_message, size_t message_length
) {
    std::size_t raw_length = b64_input(
        from_c(one_time_key_message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    return from_c(session)->new_inbound_session(
538
539
540
541
542
543
544
545
546
547
548
        *from_c(account), nullptr, from_c(one_time_key_message), raw_length
    );
}


size_t olm_create_inbound_session_from(
    OlmSession * session,
    OlmAccount * account,
    void const * their_identity_key, size_t their_identity_key_length,
    void * one_time_key_message, size_t message_length
) {
549
550
551
552
    std::uint8_t const * id_key = from_c(their_identity_key);
    std::size_t id_key_length = their_identity_key_length;

    if (olm::decode_base64_length(id_key_length) != olm::KEY_LENGTH) {
553
        from_c(session)->last_error = OlmErrorCode::OLM_INVALID_BASE64;
554
555
556
        return std::size_t(-1);
    }
    olm::Curve25519PublicKey identity_key;
557
    olm::decode_base64(id_key, id_key_length, identity_key.public_key);
558
559
560
561
562
563
564
565
566
567

    std::size_t raw_length = b64_input(
        from_c(one_time_key_message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    return from_c(session)->new_inbound_session(
        *from_c(account), &identity_key,
        from_c(one_time_key_message), raw_length
568
569
570
571
    );
}


572
573
574
575
576
577
578
579
580
581
582
583
584
size_t olm_session_id_length(
    OlmSession * session
) {
    return b64_output_length(from_c(session)->session_id_length());
}

size_t olm_session_id(
    OlmSession * session,
    void * id, size_t id_length
) {
    std::size_t raw_length = from_c(session)->session_id_length();
    if (id_length < b64_output_length(raw_length)) {
        from_c(session)->last_error =
585
                OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
586
587
588
589
590
591
592
593
594
595
596
597
        return std::size_t(-1);
    }
    std::size_t result = from_c(session)->session_id(
       b64_output_pos(from_c(id), raw_length), raw_length
    );
    if (result == std::size_t(-1)) {
        return result;
    }
    return b64_output(from_c(id), raw_length);
}


598
599
size_t olm_matches_inbound_session(
    OlmSession * session,
600
601
602
603
604
605
606
607
608
    void * one_time_key_message, size_t message_length
) {
    std::size_t raw_length = b64_input(
        from_c(one_time_key_message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    bool matches = from_c(session)->matches_inbound_session(
609
610
611
612
613
614
615
616
617
618
619
        nullptr, from_c(one_time_key_message), raw_length
    );
    return matches ? 1 : 0;
}


size_t olm_matches_inbound_session_from(
    OlmSession * session,
    void const * their_identity_key, size_t their_identity_key_length,
    void * one_time_key_message, size_t message_length
) {
620
621
622
623
    std::uint8_t const * id_key = from_c(their_identity_key);
    std::size_t id_key_length = their_identity_key_length;

    if (olm::decode_base64_length(id_key_length) != olm::KEY_LENGTH) {
624
        from_c(session)->last_error = OlmErrorCode::OLM_INVALID_BASE64;
625
626
627
        return std::size_t(-1);
    }
    olm::Curve25519PublicKey identity_key;
628
    olm::decode_base64(id_key, id_key_length, identity_key.public_key);
629
630
631
632
633
634
635
636
637

    std::size_t raw_length = b64_input(
        from_c(one_time_key_message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    bool matches = from_c(session)->matches_inbound_session(
        &identity_key, from_c(one_time_key_message), raw_length
638
639
640
641
642
    );
    return matches ? 1 : 0;
}


643
644
645
size_t olm_remove_one_time_keys(
    OlmAccount * account,
    OlmSession * session
646
647
) {
    size_t result = from_c(account)->remove_key(
648
        from_c(session)->bob_one_time_key
649
650
    );
    if (result == std::size_t(-1)) {
651
        from_c(account)->last_error = OlmErrorCode::OLM_BAD_MESSAGE_KEY_ID;
652
653
654
655
656
    }
    return result;
}


657
658
size_t olm_encrypt_message_type(
    OlmSession * session
659
660
661
662
663
) {
    return size_t(from_c(session)->encrypt_message_type());
}


664
665
size_t olm_encrypt_random_length(
    OlmSession * session
666
667
668
669
670
) {
    return from_c(session)->encrypt_random_length();
}


671
672
size_t olm_encrypt_message_length(
    OlmSession * session,
673
674
675
676
677
678
679
680
    size_t plaintext_length
) {
    return b64_output_length(
        from_c(session)->encrypt_message_length(plaintext_length)
    );
}


681
682
size_t olm_encrypt(
    OlmSession * session,
683
    void const * plaintext, size_t plaintext_length,
684
    void * random, size_t random_length,
685
686
687
688
689
    void * message, size_t message_length
) {
    std::size_t raw_length = from_c(session)->encrypt_message_length(
        plaintext_length
    );
690
    if (message_length < b64_output_length(raw_length)) {
691
        from_c(session)->last_error =
692
            OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
693
694
        return std::size_t(-1);
    }
695
    std::size_t result = from_c(session)->encrypt(
696
697
698
699
        from_c(plaintext), plaintext_length,
        from_c(random), random_length,
        b64_output_pos(from_c(message), raw_length), raw_length
    );
700
    olm::unset(random, random_length);
701
702
703
    if (result == std::size_t(-1)) {
        return result;
    }
704
705
706
707
    return b64_output(from_c(message), raw_length);
}


708
709
size_t olm_decrypt_max_plaintext_length(
    OlmSession * session,
710
711
712
713
714
715
716
717
718
719
    size_t message_type,
    void * message, size_t message_length
) {
    std::size_t raw_length = b64_input(
        from_c(message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    return from_c(session)->decrypt_max_plaintext_length(
720
        olm::MessageType(message_type), from_c(message), raw_length
721
722
723
724
    );
}


725
726
size_t olm_decrypt(
    OlmSession * session,
727
728
729
730
731
732
733
734
735
736
737
    size_t message_type,
    void * message, size_t message_length,
    void * plaintext, size_t max_plaintext_length
) {
    std::size_t raw_length = b64_input(
        from_c(message), message_length, from_c(session)->last_error
    );
    if (raw_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    return from_c(session)->decrypt(
738
        olm::MessageType(message_type), from_c(message), raw_length,
739
740
741
742
        from_c(plaintext), max_plaintext_length
    );
}

743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758

size_t olm_sha256_length(
   OlmUtility * utility
) {
    return b64_output_length(from_c(utility)->sha256_length());
}


size_t olm_sha256(
    OlmUtility * utility,
    void const * input, size_t input_length,
    void * output, size_t output_length
) {
    std::size_t raw_length = from_c(utility)->sha256_length();
    if (output_length < b64_output_length(raw_length)) {
        from_c(utility)->last_error =
759
            OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
        return std::size_t(-1);
    }
    std::size_t result = from_c(utility)->sha256(
       from_c(input), input_length,
       b64_output_pos(from_c(output), raw_length), raw_length
    );
    if (result == std::size_t(-1)) {
        return result;
    }
    return b64_output(from_c(output), raw_length);
}


size_t olm_ed25519_verify(
    OlmUtility * utility,
    void const * key, size_t key_length,
    void const * message, size_t message_length,
    void * signature, size_t signature_length
) {
779
    if (olm::decode_base64_length(key_length) != olm::KEY_LENGTH) {
780
        from_c(utility)->last_error = OlmErrorCode::OLM_INVALID_BASE64;
781
782
783
        return std::size_t(-1);
    }
    olm::Ed25519PublicKey verify_key;
784
    olm::decode_base64(from_c(key), key_length, verify_key.public_key);
785
786
787
788
789
790
791
792
793
794
795
796
797
    std::size_t raw_signature_length = b64_input(
        from_c(signature), signature_length, from_c(utility)->last_error
    );
    if (raw_signature_length == std::size_t(-1)) {
        return std::size_t(-1);
    }
    return from_c(utility)->ed25519_verify(
        verify_key,
        from_c(message), message_length,
        from_c(signature), raw_signature_length
    );
}

798
}