summaryrefslogtreecommitdiffstats
path: root/engines/e_ossltest.c
blob: 64376247c3f0334ec36d3ed5aeeaca28ab9489d4 (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
/*
 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/*
 * This is the OSSLTEST engine. It provides deliberately crippled digest
 * implementations for test purposes. It is highly insecure and must NOT be
 * used for any purpose except testing
 */

#include <stdio.h>
#include <string.h>

#include <openssl/engine.h>
#include <openssl/sha.h>
#include <openssl/md5.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/modes.h>
#include <openssl/aes.h>
#include <openssl/rand.h>
#include <openssl/crypto.h>

#include "e_ossltest_err.c"

/* Engine Id and Name */
static const char *engine_ossltest_id = "ossltest";
static const char *engine_ossltest_name = "OpenSSL Test engine support";


/* Engine Lifetime functions */
static int ossltest_destroy(ENGINE *e);
static int ossltest_init(ENGINE *e);
static int ossltest_finish(ENGINE *e);
void ENGINE_load_ossltest(void);


/* Set up digests */
static int ossltest_digests(ENGINE *e, const EVP_MD **digest,
                          const int **nids, int nid);
static const RAND_METHOD *ossltest_rand_method(void);

/* MD5 */
static int digest_md5_init(EVP_MD_CTX *ctx);
static int digest_md5_update(EVP_MD_CTX *ctx, const void *data,
                             size_t count);
static int digest_md5_final(EVP_MD_CTX *ctx, unsigned char *md);

static EVP_MD *_hidden_md5_md = NULL;
static const EVP_MD *digest_md5(void)
{
    if (_hidden_md5_md == NULL) {
        EVP_MD *md;

        if ((md = EVP_MD_meth_new(NID_md5, NID_md5WithRSAEncryption)) == NULL
            || !EVP_MD_meth_set_result_size(md, MD5_DIGEST_LENGTH)
            || !EVP_MD_meth_set_input_blocksize(md, MD5_CBLOCK)
            || !EVP_MD_meth_set_app_datasize(md,
                                             sizeof(EVP_MD *) + sizeof(MD5_CTX))
            || !EVP_MD_meth_set_flags(md, 0)
            || !EVP_MD_meth_set_init(md, digest_md5_init)
            || !EVP_MD_meth_set_update(md, digest_md5_update)
            || !EVP_MD_meth_set_final(md, digest_md5_final)) {
            EVP_MD_meth_free(md);
            md = NULL;
        }
        _hidden_md5_md = md;
    }
    return _hidden_md5_md;
}

/* SHA1 */
static int digest_sha1_init(EVP_MD_CTX *ctx);
static int digest_sha1_update(EVP_MD_CTX *ctx, const void *data,
                              size_t count);
static int digest_sha1_final(EVP_MD_CTX *ctx, unsigned char *md);

static EVP_MD *_hidden_sha1_md = NULL;
static const EVP_MD *digest_sha1(void)
{
    if (_hidden_sha1_md == NULL) {
        EVP_MD *md;

        if ((md = EVP_MD_meth_new(NID_sha1, NID_sha1WithRSAEncryption)) == NULL
            || !EVP_MD_meth_set_result_size(md, SHA_DIGEST_LENGTH)
            || !EVP_MD_meth_set_input_blocksize(md, SHA_CBLOCK)
            || !EVP_MD_meth_set_app_datasize(md,
                                             sizeof(EVP_MD *) + sizeof(SHA_CTX))
            || !EVP_MD_meth_set_flags(md, EVP_MD_FLAG_DIGALGID_ABSENT)
            || !EVP_MD_meth_set_init(md, digest_sha1_init)
            || !EVP_MD_meth_set_update(md, digest_sha1_update)
            || !EVP_MD_meth_set_final(md, digest_sha1_final)) {
            EVP_MD_meth_free(md);
            md = NULL;
        }
        _hidden_sha1_md = md;
    }
    return _hidden_sha1_md;
}

/* SHA256 */
static int digest_sha256_init(EVP_MD_CTX *ctx);
static int digest_sha256_update(EVP_MD_CTX *ctx, const void *data,
                                size_t count);
static int digest_sha256_final(EVP_MD_CTX *ctx, unsigned char *md);

static EVP_MD *_hidden_sha256_md = NULL;
static const EVP_MD *digest_sha256(void)
{
    if (_hidden_sha256_md == NULL) {
        EVP_MD *md;

        if ((md = EVP_MD_meth_new(NID_sha256, NID_sha256WithRSAEncryption)) == NULL
            || !EVP_MD_meth_set_result_size(md, SHA256_DIGEST_LENGTH)
            || !EVP_MD_meth_set_input_blocksize(md, SHA256_CBLOCK)
            || !EVP_MD_meth_set_app_datasize(md,
                                             sizeof(EVP_MD *) + sizeof(SHA256_CTX))
            || !EVP_MD_meth_set_flags(md, EVP_MD_FLAG_DIGALGID_ABSENT)
            || !EVP_MD_meth_set_init(md, digest_sha256_init)
            || !EVP_MD_meth_set_update(md, digest_sha256_update)
            || !EVP_MD_meth_set_final(md, digest_sha256_final)) {
            EVP_MD_meth_free(md);
            md = NULL;
        }
        _hidden_sha256_md = md;
    }
    return _hidden_sha256_md;
}

/* SHA384/SHA512 */
static int digest_sha384_init(EVP_MD_CTX *ctx);
static int digest_sha512_init(EVP_MD_CTX *ctx);
static int digest_sha512_update(EVP_MD_CTX *ctx, const void *data,
                                size_t count);
static int digest_sha384_final(EVP_MD_CTX *ctx, unsigned char *md);
static int digest_sha512_final(EVP_MD_CTX *ctx, unsigned char *md);

static EVP_MD *_hidden_sha384_md = NULL;
static const EVP_MD *digest_sha384(void)
{
    if (_hidden_sha384_md == NULL) {
        EVP_MD *md;

        if ((md = EVP_MD_meth_new(NID_sha384, NID_sha384WithRSAEncryption)) == NULL
            || !EVP_MD_meth_set_result_size(md, SHA384_DIGEST_LENGTH)
            || !EVP_MD_meth_set_input_blocksize(md, SHA512_CBLOCK)
            || !EVP_MD_meth_set_app_datasize(md,
                                             sizeof(EVP_MD *) + sizeof(SHA512_CTX))
            || !EVP_MD_meth_set_flags(md, EVP_MD_FLAG_DIGALGID_ABSENT)
            || !EVP_MD_meth_set_init(md, digest_sha384_init)
            || !EVP_MD_meth_set_update(md, digest_sha512_update)
            || !EVP_MD_meth_set_final(md, digest_sha384_final)) {
            EVP_MD_meth_free(md);
            md = NULL;
        }
        _hidden_sha384_md = md;
    }
    return _hidden_sha384_md;
}
static EVP_MD *_hidden_sha512_md = NULL;
static const EVP_MD *digest_sha512(void)
{
    if (_hidden_sha512_md == NULL) {
        EVP_MD *md;

        if ((md = EVP_MD_meth_new(NID_sha512, NID_sha512WithRSAEncryption)) == NULL
            || !EVP_MD_meth_set_result_size(md, SHA512_DIGEST_LENGTH)
            || !EVP_MD_meth_set_input_blocksize(md, SHA512_CBLOCK)
            || !EVP_MD_meth_set_app_datasize(md,
                                             sizeof(EVP_MD *) + sizeof(SHA512_CTX))
            || !EVP_MD_meth_set_flags(md, EVP_MD_FLAG_DIGALGID_ABSENT)
            || !EVP_MD_meth_set_init(md, digest_sha512_init)
            || !EVP_MD_meth_set_update(md, digest_sha512_update)
            || !EVP_MD_meth_set_final(md, digest_sha512_final)) {
            EVP_MD_meth_free(md);
            md = NULL;
        }
        _hidden_sha512_md = md;
    }
    return _hidden_sha512_md;
}
static void destroy_digests(void)
{
    EVP_MD_meth_free(_hidden_md5_md);
    _hidden_md5_md = NULL;
    EVP_MD_meth_free(_hidden_sha1_md);
    _hidden_sha1_md = NULL;
    EVP_MD_meth_free(_hidden_sha256_md);
    _hidden_sha256_md = NULL;
    EVP_MD_meth_free(_hidden_sha384_md);
    _hidden_sha384_md = NULL;
    EVP_MD_meth_free(_hidden_sha512_md);
    _hidden_sha512_md = NULL;
}
static int ossltest_digest_nids(const int **nids)
{
    static int digest_nids[6] = { 0, 0, 0, 0, 0, 0 };
    static int pos = 0;
    static int init = 0;

    if (!init) {
        const EVP_MD *md;
        if ((md = digest_md5()) != NULL)
            digest_nids[pos++] = EVP_MD_type(md);
        if ((md = digest_sha1()) != NULL)
            digest_nids[pos++] = EVP_MD_type(md);
        if ((md = digest_sha256()) != NULL)
            digest_nids[pos++] = EVP_MD_type(md);
        if ((md = digest_sha384()) != NULL)
            digest_nids[pos++] = EVP_MD_type(md);
        if ((md = digest_sha512()) != NULL)
            digest_nids[pos++] = EVP_MD_type(md);
        digest_nids[pos] = 0;
        init = 1;
    }
    *nids = digest_nids;
    return pos;
}

/* Setup ciphers */
static int ossltest_ciphers(ENGINE *, const EVP_CIPHER **,
                            const int **, int);

static int ossltest_cipher_nids[] = {
    NID_aes_128_cbc, NID_aes_128_gcm, 0
};

/* AES128 */

int ossltest_aes128_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
                             const unsigned char *iv, int enc);
int ossltest_aes128_cbc_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                               const unsigned char *in, size_t inl);
int ossltest_aes128_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
                             const unsigned char *iv, int enc);
int ossltest_aes128_gcm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                               const unsigned char *in, size_t inl);
static int ossltest_aes128_gcm_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
                                    void *ptr);

static EVP_CIPHER *_hidden_aes_128_cbc = NULL;
static const EVP_CIPHER *ossltest_aes_128_cbc(void)
{
    if (_hidden_aes_128_cbc == NULL
        && ((_hidden_aes_128_cbc = EVP_CIPHER_meth_new(NID_aes_128_cbc,
                                                       16 /* block size */,
                                                       16 /* key len */)) == NULL
            || !EVP_CIPHER_meth_set_iv_length(_hidden_aes_128_cbc,16)
            || !EVP_CIPHER_meth_set_flags(_hidden_aes_128_cbc,
                                          EVP_CIPH_FLAG_DEFAULT_ASN1
                                          | EVP_CIPH_CBC_MODE)
            || !EVP_CIPHER_meth_set_init(_hidden_aes_128_cbc,
                                         ossltest_aes128_init_key)
            || !EVP_CIPHER_meth_set_do_cipher(_hidden_aes_128_cbc,
                                              ossltest_aes128_cbc_cipher)
            || !EVP_CIPHER_meth_set_impl_ctx_size(_hidden_aes_128_cbc,
                                                  EVP_CIPHER_impl_ctx_size(EVP_aes_128_cbc())))) {
        EVP_CIPHER_meth_free(_hidden_aes_128_cbc);
        _hidden_aes_128_cbc = NULL;
    }
    return _hidden_aes_128_cbc;
}
static EVP_CIPHER *_hidden_aes_128_gcm = NULL;

#define AES_GCM_FLAGS   (EVP_CIPH_FLAG_DEFAULT_ASN1 \
                | EVP_CIPH_CUSTOM_IV | EVP_CIPH_FLAG_CUSTOM_CIPHER \
                | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CTRL_INIT \
                | EVP_CIPH_CUSTOM_COPY |EVP_CIPH_FLAG_AEAD_CIPHER \
                | EVP_CIPH_GCM_MODE)

static const EVP_CIPHER *ossltest_aes_128_gcm(void)
{
    if (_hidden_aes_128_gcm == NULL
        && ((_hidden_aes_128_gcm = EVP_CIPHER_meth_new(NID_aes_128_gcm,
                                                       1 /* block size */,
                                                       16 /* key len */)) == NULL
            || !EVP_CIPHER_meth_set_iv_length(_hidden_aes_128_gcm,12)
            || !EVP_CIPHER_meth_set_flags(_hidden_aes_128_gcm, AES_GCM_FLAGS)
            || !EVP_CIPHER_meth_set_init(_hidden_aes_128_gcm,
                                         ossltest_aes128_gcm_init_key)
            || !EVP_CIPHER_meth_set_do_cipher(_hidden_aes_128_gcm,
                                              ossltest_aes128_gcm_cipher)
            || !EVP_CIPHER_meth_set_ctrl(_hidden_aes_128_gcm,
                                              ossltest_aes128_gcm_ctrl)
            || !EVP_CIPHER_meth_set_impl_ctx_size(_hidden_aes_128_gcm,
                              EVP_CIPHER_impl_ctx_size(EVP_aes_128_gcm())))) {
        EVP_CIPHER_meth_free(_hidden_aes_128_gcm);
        _hidden_aes_128_gcm = NULL;
    }
    return _hidden_aes_128_gcm;
}

static void destroy_ciphers(void)
{
    EVP_CIPHER_meth_free(_hidden_aes_128_cbc);
    EVP_CIPHER_meth_free(_hidden_aes_128_gcm);
    _hidden_aes_128_cbc = NULL;
}

static int bind_ossltest(ENGINE *e)
{
    /* Ensure the ossltest error handling is set up */
    ERR_load_OSSLTEST_strings();

    if (!ENGINE_set_id(e, engine_ossltest_id)
        || !ENGINE_set_name(e, engine_ossltest_name)
        || !ENGINE_set_digests(e, ossltest_digests)
        || !ENGINE_set_ciphers(e, ossltest_ciphers)
        || !ENGINE_set_RAND(e, ossltest_rand_method())
        || !ENGINE_set_destroy_function(e, ossltest_destroy)
        || !ENGINE_set_init_function(e, ossltest_init)
        || !ENGINE_set_finish_function(e, ossltest_finish)) {
        OSSLTESTerr(OSSLTEST_F_BIND_OSSLTEST, OSSLTEST_R_INIT_FAILED);
        return 0;
    }

    return 1;
}

#ifndef OPENSSL_NO_DYNAMIC_ENGINE
static int bind_helper(ENGINE *e, const char *id)
{
    if (id && (strcmp(id, engine_ossltest_id) != 0))
        return 0;
    if (!bind_ossltest(e))
        return 0;
    return 1;
}

IMPLEMENT_DYNAMIC_CHECK_FN()
    IMPLEMENT_DYNAMIC_BIND_FN(bind_helper)
#endif

static ENGINE *engine_ossltest(void)
{
    ENGINE *ret = ENGINE_new();
    if (ret == NULL)
        return NULL;
    if (!bind_ossltest(ret)) {
        ENGINE_free(ret);
        return NULL;
    }
    return ret;
}

void ENGINE_load_ossltest(void)
{
    /* Copied from eng_[openssl|dyn].c */
    ENGINE *toadd = engine_ossltest();
    if (!toadd)
        return;
    ENGINE_add(toadd);
    ENGINE_free(toadd);
    ERR_clear_error();
}


static int ossltest_init(ENGINE *e)
{
    return 1;
}


static int ossltest_finish(ENGINE *e)
{
    return 1;
}


static int ossltest_destroy(ENGINE *e)
{
    destroy_digests();
    destroy_ciphers();
    ERR_unload_OSSLTEST_strings();
    return 1;
}

static int ossltest_digests(ENGINE *e, const EVP_MD **digest,
                          const int **nids, int nid)
{
    int ok = 1;
    if (!digest) {
        /* We are returning a list of supported nids */
        return ossltest_digest_nids(nids);
    }
    /* We are being asked for a specific digest */
    switch (nid) {
    case NID_md5:
        *digest = digest_md5();
        break;
    case NID_sha1:
        *digest = digest_sha1();
        break;
    case NID_sha256:
        *digest = digest_sha256();
        break;
    case NID_sha384:
        *digest = digest_sha384();
        break;
    case NID_sha512:
        *digest = digest_sha512();
        break;
    default:
        ok = 0;
        *digest = NULL;
        break;
    }
    return ok;
}

static int ossltest_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
                          const int **nids, int nid)
{
    int ok = 1;
    if (!cipher) {
        /* We are returning a list of supported nids */
        *nids = ossltest_cipher_nids;
        return (sizeof(ossltest_cipher_nids) - 1)
               / sizeof(ossltest_cipher_nids[0]);
    }
    /* We are being asked for a specific cipher */
    switch (nid) {
    case NID_aes_128_cbc:
        *cipher = ossltest_aes_128_cbc();
        break;
    case NID_aes_128_gcm:
        *cipher = ossltest_aes_128_gcm();
        break;
    default:
        ok = 0;
        *cipher = NULL;
        break;
    }
    return ok;
}

static void fill_known_data(unsigned char *md, unsigned int len)
{
    unsigned int i;

    for (i=0; i<len; i++) {
        md[i] = (unsigned char)(i & 0xff);
    }
}

/*
 * MD5 implementation. We go through the motions of doing MD5 by deferring to
 * the standard implementation. Then we overwrite the result with a will defined
 * value, so that all "MD5" digests using the test engine always end up with
 * the same value.
 */
#undef data
#define data(ctx) ((MD5_CTX *)EVP_MD_CTX_md_data(ctx))
static int digest_md5_init(EVP_MD_CTX *ctx)
{
    return MD5_Init(data(ctx));
}

static int digest_md5_update(EVP_MD_CTX *ctx, const void *data,
                             size_t count)
{
    return MD5_Update(data(ctx), data, (size_t)count);
}

static int digest_md5_final(EVP_MD_CTX *ctx, unsigned char *md)
{
    int ret;
    ret = MD5_Final(md, data(ctx));

    if (ret > 0) {
        fill_known_data(md, MD5_DIGEST_LENGTH);
    }
    return ret;
}

/*
 * SHA1 implementation.
 */
#undef data
#define data(ctx) ((SHA_CTX *)EVP_MD_CTX_md_data(ctx))
static int digest_sha1_init(EVP_MD_CTX *ctx)
{
    return SHA1_Init(data(ctx));
}

static int digest_sha1_update(EVP_MD_CTX *ctx, const void *data,
                              size_t count)
{
    return SHA1_Update(data(ctx), data, (size_t)count);
}

static int digest_sha1_final(EVP_MD_CTX *ctx, unsigned char *md)
{
    int ret;
    ret = SHA1_Final(md, data(ctx));

    if (ret > 0) {
        fill_known_data(md, SHA_DIGEST_LENGTH);
    }
    return ret;
}

/*
 * SHA256 implementation.
 */
#undef data
#define data(ctx) ((SHA256_CTX *)EVP_MD_CTX_md_data(ctx))
static int digest_sha256_init(EVP_MD_CTX *ctx)
{
    return SHA256_Init(data(ctx));
}

static int digest_sha256_update(EVP_MD_CTX *ctx, const void *data,
                                size_t count)
{
    return SHA256_Update(data(ctx), data, (size_t)count);
}

static int digest_sha256_final(EVP_MD_CTX *ctx, unsigned char *md)
{
    int ret;
    ret = SHA256_Final(md, data(ctx));

    if (ret > 0) {
        fill_known_data(md, SHA256_DIGEST_LENGTH);
    }
    return ret;
}

/*
 * SHA384/512 implementation.
 */
#undef data
#define data(ctx) ((SHA512_CTX *)EVP_MD_CTX_md_data(ctx))
static int digest_sha384_init(EVP_MD_CTX *ctx)
{
    return SHA384_Init(data(ctx));
}

static int digest_sha512_init(EVP_MD_CTX *ctx)
{
    return SHA512_Init(data(ctx));
}

static int digest_sha512_update(EVP_MD_CTX *ctx, const void *data,
                                size_t count)
{
    return SHA512_Update(data(ctx), data, (size_t)count);
}

static int digest_sha384_final(EVP_MD_CTX *ctx, unsigned char *md)
{
    int ret;
    /* Actually uses SHA512_Final! */
    ret = SHA512_Final(md, data(ctx));

    if (ret > 0) {
        fill_known_data(md, SHA384_DIGEST_LENGTH);
    }
    return ret;
}

static int digest_sha512_final(EVP_MD_CTX *ctx, unsigned char *md)
{
    int ret;
    ret = SHA512_Final(md, data(ctx));

    if (ret > 0) {
        fill_known_data(md, SHA512_DIGEST_LENGTH);
    }
    return ret;
}

/*
 * AES128 Implementation
 */

int ossltest_aes128_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
                             const unsigned char *iv, int enc)
{
    return EVP_CIPHER_meth_get_init(EVP_aes_128_cbc()) (ctx, key, iv, enc);
}

int ossltest_aes128_cbc_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                               const unsigned char *in, size_t inl)
{
    unsigned char *tmpbuf;
    int ret;

    tmpbuf = OPENSSL_malloc(inl);

    /* OPENSSL_malloc will return NULL if inl == 0 */
    if (tmpbuf == NULL && inl > 0)
        return -1;

    /* Remember what we were asked to encrypt */
    if (tmpbuf != NULL)
        memcpy(tmpbuf, in, inl);

    /* Go through the motions of encrypting it */
    ret = EVP_CIPHER_meth_get_do_cipher(EVP_aes_128_cbc())(ctx, out, in, inl);

    /* Throw it all away and just use the plaintext as the output */
    if (tmpbuf != NULL)
        memcpy(out, tmpbuf, inl);
    OPENSSL_free(tmpbuf);

    return ret;
}

int ossltest_aes128_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
                             const unsigned char *iv, int enc)
{
    return EVP_CIPHER_meth_get_init(EVP_aes_128_gcm()) (ctx, key, iv, enc);
}


int ossltest_aes128_gcm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
                               const unsigned char *in, size_t inl)
{
    unsigned char *tmpbuf = OPENSSL_malloc(inl);

    /* OPENSSL_malloc will return NULL if inl == 0 */
    if (tmpbuf == NULL && inl > 0)
        return -1;

    /* Remember what we were asked to encrypt */
    if (tmpbuf != NULL)
        memcpy(tmpbuf, in, inl);

    /* Go through the motions of encrypting it */
    EVP_CIPHER_meth_get_do_cipher(EVP_aes_128_gcm())(ctx, out, in, inl);

    /* Throw it all away and just use the plaintext as the output */
    if (tmpbuf != NULL && out != NULL)
        memcpy(out, tmpbuf, inl);
    OPENSSL_free(tmpbuf);

    return inl;
}

static int ossltest_aes128_gcm_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg,
                                    void *ptr)
{
    /* Pass the ctrl down */
    int ret = EVP_CIPHER_meth_get_ctrl(EVP_aes_128_gcm())(ctx, type, arg, ptr);

    if (ret <= 0)
        return ret;

    switch(type) {
    case EVP_CTRL_AEAD_GET_TAG:
        /* Always give the same tag */
        memset(ptr, 0, EVP_GCM_TLS_TAG_LEN);
        break;

    default:
        break;
    }

    return 1;
}

static int ossltest_rand_bytes(unsigned char *buf, int num)
{
    unsigned char val = 1;

    while (--num >= 0)
        *buf++ = val++;
    return 1;
}

static int ossltest_rand_status(void)
{
    return 1;
}

static const RAND_METHOD *ossltest_rand_method(void)
{

    static RAND_METHOD osslt_rand_meth = {
        NULL,
        ossltest_rand_bytes,
        NULL,
        NULL,
        ossltest_rand_bytes,
        ossltest_rand_status
    };

    return &osslt_rand_meth;
}