aboutsummaryrefslogtreecommitdiffstats
path: root/engines/e_atalla.c
blob: 7d136fff073632db3b250eb97bc1aee03053152b (plain) (blame)
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
/* crypto/engine/hw_atalla.c */
/*
 * Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL project
 * 2000.
 */
/* ====================================================================
 * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/buffer.h>
#include <openssl/dso.h>
#include <openssl/engine.h>
#ifndef OPENSSL_NO_RSA
# include <openssl/rsa.h>
#endif
#ifndef OPENSSL_NO_DSA
# include <openssl/dsa.h>
#endif
#ifndef OPENSSL_NO_DH
# include <openssl/dh.h>
#endif
#include <openssl/bn.h>

#ifndef OPENSSL_NO_HW
# ifndef OPENSSL_NO_HW_ATALLA

#  ifdef FLAT_INC
#   include "atalla.h"
#  else
#   include "vendor_defns/atalla.h"
#  endif

#  define ATALLA_LIB_NAME "atalla engine"
#  include "e_atalla_err.c"

static int atalla_destroy(ENGINE *e);
static int atalla_init(ENGINE *e);
static int atalla_finish(ENGINE *e);
static int atalla_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void));

/* BIGNUM stuff */
static int atalla_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                          const BIGNUM *m, BN_CTX *ctx);

#  ifndef OPENSSL_NO_RSA
/* RSA stuff */
static int atalla_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
                              BN_CTX *ctx);
/* This function is aliased to mod_exp (with the mont stuff dropped). */
static int atalla_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                               const BIGNUM *m, BN_CTX *ctx,
                               BN_MONT_CTX *m_ctx);
#  endif

#  ifndef OPENSSL_NO_DSA
/* DSA stuff */
static int atalla_dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1,
                              BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m,
                              BN_CTX *ctx, BN_MONT_CTX *in_mont);
static int atalla_mod_exp_dsa(DSA *dsa, BIGNUM *r, BIGNUM *a,
                              const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
                              BN_MONT_CTX *m_ctx);
#  endif

#  ifndef OPENSSL_NO_DH
/* DH stuff */
/* This function is alised to mod_exp (with the DH and mont dropped). */
static int atalla_mod_exp_dh(const DH *dh, BIGNUM *r,
                             const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *m, BN_CTX *ctx,
                             BN_MONT_CTX *m_ctx);
#  endif

/* The definitions for control commands specific to this engine */
#  define ATALLA_CMD_SO_PATH              ENGINE_CMD_BASE
static const ENGINE_CMD_DEFN atalla_cmd_defns[] = {
    {ATALLA_CMD_SO_PATH,
     "SO_PATH",
     "Specifies the path to the 'atasi' shared library",
     ENGINE_CMD_FLAG_STRING},
    {0, NULL, NULL, 0}
};

#  ifndef OPENSSL_NO_RSA
/* Our internal RSA_METHOD that we provide pointers to */
static RSA_METHOD atalla_rsa = {
    "Atalla RSA method",
    NULL,
    NULL,
    NULL,
    NULL,
    atalla_rsa_mod_exp,
    atalla_mod_exp_mont,
    NULL,
    NULL,
    0,
    NULL,
    NULL,
    NULL,
    NULL
};
#  endif

#  ifndef OPENSSL_NO_DSA
/* Our internal DSA_METHOD that we provide pointers to */
static DSA_METHOD atalla_dsa = {
    "Atalla DSA method",
    NULL,                       /* dsa_do_sign */
    NULL,                       /* dsa_sign_setup */
    NULL,                       /* dsa_do_verify */
    atalla_dsa_mod_exp,         /* dsa_mod_exp */
    atalla_mod_exp_dsa,         /* bn_mod_exp */
    NULL,                       /* init */
    NULL,                       /* finish */
    0,                          /* flags */
    NULL,                       /* app_data */
    NULL,                       /* dsa_paramgen */
    NULL                        /* dsa_keygen */
};
#  endif

#  ifndef OPENSSL_NO_DH
/* Our internal DH_METHOD that we provide pointers to */
static DH_METHOD atalla_dh = {
    "Atalla DH method",
    NULL,
    NULL,
    atalla_mod_exp_dh,
    NULL,
    NULL,
    0,
    NULL,
    NULL
};
#  endif

/* Constants used when creating the ENGINE */
static const char *engine_atalla_id = "atalla";
static const char *engine_atalla_name = "Atalla hardware engine support";

/*
 * This internal function is used by ENGINE_atalla() and possibly by the
 * "dynamic" ENGINE support too
 */
static int bind_helper(ENGINE *e)
{
#  ifndef OPENSSL_NO_RSA
    const RSA_METHOD *meth1;
#  endif
#  ifndef OPENSSL_NO_DSA
    const DSA_METHOD *meth2;
#  endif
#  ifndef OPENSSL_NO_DH
    const DH_METHOD *meth3;
#  endif
    if (!ENGINE_set_id(e, engine_atalla_id) ||
        !ENGINE_set_name(e, engine_atalla_name) ||
#  ifndef OPENSSL_NO_RSA
        !ENGINE_set_RSA(e, &atalla_rsa) ||
#  endif
#  ifndef OPENSSL_NO_DSA
        !ENGINE_set_DSA(e, &atalla_dsa) ||
#  endif
#  ifndef OPENSSL_NO_DH
        !ENGINE_set_DH(e, &atalla_dh) ||
#  endif
        !ENGINE_set_destroy_function(e, atalla_destroy) ||
        !ENGINE_set_init_function(e, atalla_init) ||
        !ENGINE_set_finish_function(e, atalla_finish) ||
        !ENGINE_set_ctrl_function(e, atalla_ctrl) ||
        !ENGINE_set_cmd_defns(e, atalla_cmd_defns))
        return 0;

#  ifndef OPENSSL_NO_RSA
    /*
     * We know that the "PKCS1_SSLeay()" functions hook properly to the
     * atalla-specific mod_exp and mod_exp_crt so we use those functions. NB:
     * We don't use ENGINE_openssl() or anything "more generic" because
     * something like the RSAref code may not hook properly, and if you own
     * one of these cards then you have the right to do RSA operations on it
     * anyway!
     */
    meth1 = RSA_PKCS1_SSLeay();
    atalla_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
    atalla_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
    atalla_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
    atalla_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
#  endif

#  ifndef OPENSSL_NO_DSA
    /*
     * Use the DSA_OpenSSL() method and just hook the mod_exp-ish bits.
     */
    meth2 = DSA_OpenSSL();
    atalla_dsa.dsa_do_sign = meth2->dsa_do_sign;
    atalla_dsa.dsa_sign_setup = meth2->dsa_sign_setup;
    atalla_dsa.dsa_do_verify = meth2->dsa_do_verify;
#  endif

#  ifndef OPENSSL_NO_DH
    /* Much the same for Diffie-Hellman */
    meth3 = DH_OpenSSL();
    atalla_dh.generate_key = meth3->generate_key;
    atalla_dh.compute_key = meth3->compute_key;
#  endif

    /* Ensure the atalla error handling is set up */
    ERR_load_ATALLA_strings();
    return 1;
}

#  ifdef OPENSSL_NO_DYNAMIC_ENGINE
static ENGINE *engine_atalla(void)
{
    ENGINE *ret = ENGINE_new();
    if (!ret)
        return NULL;
    if (!bind_helper(ret)) {
        ENGINE_free(ret);
        return NULL;
    }
    return ret;
}

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

/*
 * This is a process-global DSO handle used for loading and unloading the
 * Atalla library. NB: This is only set (or unset) during an init() or
 * finish() call (reference counts permitting) and they're operating with
 * global locks, so this should be thread-safe implicitly.
 */
static DSO *atalla_dso = NULL;

/*
 * These are the function pointers that are (un)set when the library has
 * successfully (un)loaded.
 */
static tfnASI_GetHardwareConfig *p_Atalla_GetHardwareConfig = NULL;
static tfnASI_RSAPrivateKeyOpFn *p_Atalla_RSAPrivateKeyOpFn = NULL;
static tfnASI_GetPerformanceStatistics *p_Atalla_GetPerformanceStatistics =
    NULL;

/*
 * These are the static string constants for the DSO file name and the
 * function symbol names to bind to. Regrettably, the DSO name on *nix
 * appears to be "atasi.so" rather than something more consistent like
 * "libatasi.so". At the time of writing, I'm not sure what the file name on
 * win32 is but clearly native name translation is not possible (eg
 * libatasi.so on *nix, and atasi.dll on win32). For the purposes of testing,
 * I have created a symbollic link called "libatasi.so" so that we can use
 * native name-translation - a better solution will be needed.
 */
static const char *ATALLA_LIBNAME = NULL;
static const char *get_ATALLA_LIBNAME(void)
{
    if (ATALLA_LIBNAME)
        return ATALLA_LIBNAME;
    return "atasi";
}

static void free_ATALLA_LIBNAME(void)
{
    if (ATALLA_LIBNAME)
        OPENSSL_free((void *)ATALLA_LIBNAME);
    ATALLA_LIBNAME = NULL;
}

static long set_ATALLA_LIBNAME(const char *name)
{
    free_ATALLA_LIBNAME();
    return (((ATALLA_LIBNAME = BUF_strdup(name)) != NULL) ? 1 : 0);
}

static const char *ATALLA_F1 = "ASI_GetHardwareConfig";
static const char *ATALLA_F2 = "ASI_RSAPrivateKeyOpFn";
static const char *ATALLA_F3 = "ASI_GetPerformanceStatistics";

/* Destructor (complements the "ENGINE_atalla()" constructor) */
static int atalla_destroy(ENGINE *e)
{
    free_ATALLA_LIBNAME();
    /*
     * Unload the atalla error strings so any error state including our
     * functs or reasons won't lead to a segfault (they simply get displayed
     * without corresponding string data because none will be found).
     */
    ERR_unload_ATALLA_strings();
    return 1;
}

/* (de)initialisation functions. */
static int atalla_init(ENGINE *e)
{
    tfnASI_GetHardwareConfig *p1;
    tfnASI_RSAPrivateKeyOpFn *p2;
    tfnASI_GetPerformanceStatistics *p3;
    /*
     * Not sure of the origin of this magic value, but Ben's code had it and
     * it seemed to have been working for a few people. :-)
     */
    unsigned int config_buf[1024];

    if (atalla_dso != NULL) {
        ATALLAerr(ATALLA_F_ATALLA_INIT, ATALLA_R_ALREADY_LOADED);
        goto err;
    }
    /*
     * Attempt to load libatasi.so/atasi.dll/whatever. Needs to be changed
     * unfortunately because the Atalla drivers don't have standard library
     * names that can be platform-translated well.
     */
    /*
     * TODO: Work out how to actually map to the names the Atalla drivers
     * really use - for now a symbollic link needs to be created on the host
     * system from libatasi.so to atasi.so on unix variants.
     */
    atalla_dso = DSO_load(NULL, get_ATALLA_LIBNAME(), NULL, 0);
    if (atalla_dso == NULL) {
        ATALLAerr(ATALLA_F_ATALLA_INIT, ATALLA_R_NOT_LOADED);
        goto err;
    }
    if (!
        (p1 =
         (tfnASI_GetHardwareConfig *) DSO_bind_func(atalla_dso, ATALLA_F1))
|| !(p2 = (tfnASI_RSAPrivateKeyOpFn *) DSO_bind_func(atalla_dso, ATALLA_F2))
|| !(p3 =
     (tfnASI_GetPerformanceStatistics *) DSO_bind_func(atalla_dso,
                                                       ATALLA_F3))) {
        ATALLAerr(ATALLA_F_ATALLA_INIT, ATALLA_R_NOT_LOADED);
        goto err;
    }
    /* Copy the pointers */
    p_Atalla_GetHardwareConfig = p1;
    p_Atalla_RSAPrivateKeyOpFn = p2;
    p_Atalla_GetPerformanceStatistics = p3;
    /*
     * Perform a basic test to see if there's actually any unit running.
     */
    if (p1(0L, config_buf) != 0) {
        ATALLAerr(ATALLA_F_ATALLA_INIT, ATALLA_R_UNIT_FAILURE);
        goto err;
    }
    /* Everything's fine. */
    return 1;
 err:
    if (atalla_dso)
        DSO_free(atalla_dso);
    atalla_dso = NULL;
    p_Atalla_GetHardwareConfig = NULL;
    p_Atalla_RSAPrivateKeyOpFn = NULL;
    p_Atalla_GetPerformanceStatistics = NULL;
    return 0;
}

static int atalla_finish(ENGINE *e)
{
    free_ATALLA_LIBNAME();
    if (atalla_dso == NULL) {
        ATALLAerr(ATALLA_F_ATALLA_FINISH, ATALLA_R_NOT_LOADED);
        return 0;
    }
    if (!DSO_free(atalla_dso)) {
        ATALLAerr(ATALLA_F_ATALLA_FINISH, ATALLA_R_UNIT_FAILURE);
        return 0;
    }
    atalla_dso = NULL;
    p_Atalla_GetHardwareConfig = NULL;
    p_Atalla_RSAPrivateKeyOpFn = NULL;
    p_Atalla_GetPerformanceStatistics = NULL;
    return 1;
}

static int atalla_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
{
    int initialised = ((atalla_dso == NULL) ? 0 : 1);
    switch (cmd) {
    case ATALLA_CMD_SO_PATH:
        if (p == NULL) {
            ATALLAerr(ATALLA_F_ATALLA_CTRL, ERR_R_PASSED_NULL_PARAMETER);
            return 0;
        }
        if (initialised) {
            ATALLAerr(ATALLA_F_ATALLA_CTRL, ATALLA_R_ALREADY_LOADED);
            return 0;
        }
        return set_ATALLA_LIBNAME((const char *)p);
    default:
        break;
    }
    ATALLAerr(ATALLA_F_ATALLA_CTRL, ATALLA_R_CTRL_COMMAND_NOT_IMPLEMENTED);
    return 0;
}

static int atalla_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                          const BIGNUM *m, BN_CTX *ctx)
{
    /*
     * I need somewhere to store temporary serialised values for use with the
     * Atalla API calls. A neat cheat - I'll use BIGNUMs from the BN_CTX but
     * access their arrays directly as byte arrays <grin>. This way I don't
     * have to clean anything up.
     */
    BIGNUM *modulus;
    BIGNUM *exponent;
    BIGNUM *argument;
    BIGNUM *result;
    RSAPrivateKey keydata;
    int to_return, numbytes;

    modulus = exponent = argument = result = NULL;
    to_return = 0;              /* expect failure */

    if (!atalla_dso) {
        ATALLAerr(ATALLA_F_ATALLA_MOD_EXP, ATALLA_R_NOT_LOADED);
        goto err;
    }
    /* Prepare the params */
    BN_CTX_start(ctx);
    modulus = BN_CTX_get(ctx);
    exponent = BN_CTX_get(ctx);
    argument = BN_CTX_get(ctx);
    result = BN_CTX_get(ctx);
    if (!result) {
        ATALLAerr(ATALLA_F_ATALLA_MOD_EXP, ATALLA_R_BN_CTX_FULL);
        goto err;
    }
    if (!bn_wexpand(modulus, m->top) || !bn_wexpand(exponent, m->top) ||
        !bn_wexpand(argument, m->top) || !bn_wexpand(result, m->top)) {
        ATALLAerr(ATALLA_F_ATALLA_MOD_EXP, ATALLA_R_BN_EXPAND_FAIL);
        goto err;
    }
    /* Prepare the key-data */
    memset(&keydata, 0, sizeof(keydata));
    numbytes = BN_num_bytes(m);
    memset(exponent->d, 0, numbytes);
    memset(modulus->d, 0, numbytes);
    BN_bn2bin(p, (unsigned char *)exponent->d + numbytes - BN_num_bytes(p));
    BN_bn2bin(m, (unsigned char *)modulus->d + numbytes - BN_num_bytes(m));
    keydata.privateExponent.data = (unsigned char *)exponent->d;
    keydata.privateExponent.len = numbytes;
    keydata.modulus.data = (unsigned char *)modulus->d;
    keydata.modulus.len = numbytes;
    /* Prepare the argument */
    memset(argument->d, 0, numbytes);
    memset(result->d, 0, numbytes);
    BN_bn2bin(a, (unsigned char *)argument->d + numbytes - BN_num_bytes(a));
    /* Perform the operation */
    if (p_Atalla_RSAPrivateKeyOpFn(&keydata, (unsigned char *)result->d,
                                   (unsigned char *)argument->d,
                                   keydata.modulus.len) != 0) {
        ATALLAerr(ATALLA_F_ATALLA_MOD_EXP, ATALLA_R_REQUEST_FAILED);
        goto err;
    }
    /* Convert the response */
    BN_bin2bn((unsigned char *)result->d, numbytes, r);
    to_return = 1;
 err:
    BN_CTX_end(ctx);
    return to_return;
}

#  ifndef OPENSSL_NO_RSA
static int atalla_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
                              BN_CTX *ctx)
{
    int to_return = 0;

    if (!atalla_dso) {
        ATALLAerr(ATALLA_F_ATALLA_RSA_MOD_EXP, ATALLA_R_NOT_LOADED);
        goto err;
    }
    if (!rsa->d || !rsa->n) {
        ATALLAerr(ATALLA_F_ATALLA_RSA_MOD_EXP,
                  ATALLA_R_MISSING_KEY_COMPONENTS);
        goto err;
    }
    to_return = atalla_mod_exp(r0, I, rsa->d, rsa->n, ctx);
 err:
    return to_return;
}
#  endif

#  ifndef OPENSSL_NO_DSA
/*
 * This code was liberated and adapted from the commented-out code in
 * dsa_ossl.c. Because of the unoptimised form of the Atalla acceleration (it
 * doesn't have a CRT form for RSA), this function means that an Atalla
 * system running with a DSA server certificate can handshake around 5 or 6
 * times faster/more than an equivalent system running with RSA. Just check
 * out the "signs" statistics from the RSA and DSA parts of "openssl speed
 * -engine atalla dsa1024 rsa1024".
 */
static int atalla_dsa_mod_exp(DSA *dsa, BIGNUM *rr, BIGNUM *a1,
                              BIGNUM *p1, BIGNUM *a2, BIGNUM *p2, BIGNUM *m,
                              BN_CTX *ctx, BN_MONT_CTX *in_mont)
{
    BIGNUM t;
    int to_return = 0;

    BN_init(&t);
    /* let rr = a1 ^ p1 mod m */
    if (!atalla_mod_exp(rr, a1, p1, m, ctx))
        goto end;
    /* let t = a2 ^ p2 mod m */
    if (!atalla_mod_exp(&t, a2, p2, m, ctx))
        goto end;
    /* let rr = rr * t mod m */
    if (!BN_mod_mul(rr, rr, &t, m, ctx))
        goto end;
    to_return = 1;
 end:
    BN_free(&t);
    return to_return;
}

static int atalla_mod_exp_dsa(DSA *dsa, BIGNUM *r, BIGNUM *a,
                              const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
                              BN_MONT_CTX *m_ctx)
{
    return atalla_mod_exp(r, a, p, m, ctx);
}
#  endif

#  ifndef OPENSSL_NO_RSA
/* This function is aliased to mod_exp (with the mont stuff dropped). */
static int atalla_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
                               const BIGNUM *m, BN_CTX *ctx,
                               BN_MONT_CTX *m_ctx)
{
    return atalla_mod_exp(r, a, p, m, ctx);
}
#  endif

#  ifndef OPENSSL_NO_DH
/* This function is aliased to mod_exp (with the dh and mont dropped). */
static int atalla_mod_exp_dh(const DH *dh, BIGNUM *r,
                             const BIGNUM *a, const BIGNUM *p,
                             const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
{
    return atalla_mod_exp(r, a, p, m, ctx);
}
#  endif

/*
 * This stuff is needed if this ENGINE is being compiled into a
 * self-contained shared-library.
 */
#  ifndef OPENSSL_NO_DYNAMIC_ENGINE
static int bind_fn(ENGINE *e, const char *id)
{
    if (id && (strcmp(id, engine_atalla_id) != 0))
        return 0;
    if (!bind_helper(e))
        return 0;
    return 1;
}

IMPLEMENT_DYNAMIC_CHECK_FN()
    IMPLEMENT_DYNAMIC_BIND_FN(bind_fn)
#  endif                        /* OPENSSL_NO_DYNAMIC_ENGINE */
# endif                         /* !OPENSSL_NO_HW_ATALLA */
#endif                          /* !OPENSSL_NO_HW */