Coverage Report

Created: 2024-11-21 07:03

/src/boringssl/crypto/fipsmodule/bn/montgomery.c.inc
Line
Count
Source (jump to first uncovered line)
1
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2
 * All rights reserved.
3
 *
4
 * This package is an SSL implementation written
5
 * by Eric Young (eay@cryptsoft.com).
6
 * The implementation was written so as to conform with Netscapes SSL.
7
 *
8
 * This library is free for commercial and non-commercial use as long as
9
 * the following conditions are aheared to.  The following conditions
10
 * apply to all code found in this distribution, be it the RC4, RSA,
11
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12
 * included with this distribution is covered by the same copyright terms
13
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14
 *
15
 * Copyright remains Eric Young's, and as such any Copyright notices in
16
 * the code are not to be removed.
17
 * If this package is used in a product, Eric Young should be given attribution
18
 * as the author of the parts of the library used.
19
 * This can be in the form of a textual message at program startup or
20
 * in documentation (online or textual) provided with the package.
21
 *
22
 * Redistribution and use in source and binary forms, with or without
23
 * modification, are permitted provided that the following conditions
24
 * are met:
25
 * 1. Redistributions of source code must retain the copyright
26
 *    notice, this list of conditions and the following disclaimer.
27
 * 2. Redistributions in binary form must reproduce the above copyright
28
 *    notice, this list of conditions and the following disclaimer in the
29
 *    documentation and/or other materials provided with the distribution.
30
 * 3. All advertising materials mentioning features or use of this software
31
 *    must display the following acknowledgement:
32
 *    "This product includes cryptographic software written by
33
 *     Eric Young (eay@cryptsoft.com)"
34
 *    The word 'cryptographic' can be left out if the rouines from the library
35
 *    being used are not cryptographic related :-).
36
 * 4. If you include any Windows specific code (or a derivative thereof) from
37
 *    the apps directory (application code) you must include an acknowledgement:
38
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39
 *
40
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50
 * SUCH DAMAGE.
51
 *
52
 * The licence and distribution terms for any publically available version or
53
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
54
 * copied and put under another distribution licence
55
 * [including the GNU Public Licence.]
56
 */
57
/* ====================================================================
58
 * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
59
 *
60
 * Redistribution and use in source and binary forms, with or without
61
 * modification, are permitted provided that the following conditions
62
 * are met:
63
 *
64
 * 1. Redistributions of source code must retain the above copyright
65
 *    notice, this list of conditions and the following disclaimer.
66
 *
67
 * 2. Redistributions in binary form must reproduce the above copyright
68
 *    notice, this list of conditions and the following disclaimer in
69
 *    the documentation and/or other materials provided with the
70
 *    distribution.
71
 *
72
 * 3. All advertising materials mentioning features or use of this
73
 *    software must display the following acknowledgment:
74
 *    "This product includes software developed by the OpenSSL Project
75
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76
 *
77
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78
 *    endorse or promote products derived from this software without
79
 *    prior written permission. For written permission, please contact
80
 *    openssl-core@openssl.org.
81
 *
82
 * 5. Products derived from this software may not be called "OpenSSL"
83
 *    nor may "OpenSSL" appear in their names without prior written
84
 *    permission of the OpenSSL Project.
85
 *
86
 * 6. Redistributions of any form whatsoever must retain the following
87
 *    acknowledgment:
88
 *    "This product includes software developed by the OpenSSL Project
89
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90
 *
91
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
95
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102
 * OF THE POSSIBILITY OF SUCH DAMAGE.
103
 * ====================================================================
104
 *
105
 * This product includes cryptographic software written by Eric Young
106
 * (eay@cryptsoft.com).  This product includes software written by Tim
107
 * Hudson (tjh@cryptsoft.com). */
108
109
#include <openssl/bn.h>
110
111
#include <assert.h>
112
#include <stdio.h>
113
#include <stdlib.h>
114
#include <string.h>
115
116
#include <openssl/err.h>
117
#include <openssl/mem.h>
118
#include <openssl/thread.h>
119
120
#include "internal.h"
121
#include "../../internal.h"
122
123
124
914
void bn_mont_ctx_init(BN_MONT_CTX *mont) {
125
914
  OPENSSL_memset(mont, 0, sizeof(BN_MONT_CTX));
126
914
  BN_init(&mont->RR);
127
914
  BN_init(&mont->N);
128
914
}
129
130
914
void bn_mont_ctx_cleanup(BN_MONT_CTX *mont) {
131
914
  BN_free(&mont->RR);
132
914
  BN_free(&mont->N);
133
914
}
134
135
38.9k
BN_MONT_CTX *BN_MONT_CTX_new(void) {
136
38.9k
  BN_MONT_CTX *ret = OPENSSL_malloc(sizeof(BN_MONT_CTX));
137
38.9k
  if (ret == NULL) {
138
0
    return NULL;
139
0
  }
140
141
38.9k
  bn_mont_ctx_init(ret);
142
38.9k
  return ret;
143
38.9k
}
144
145
5.43k
void BN_MONT_CTX_free(BN_MONT_CTX *mont) {
146
5.43k
  if (mont == NULL) {
147
4.52k
    return;
148
4.52k
  }
149
150
914
  bn_mont_ctx_cleanup(mont);
151
914
  OPENSSL_free(mont);
152
914
}
153
154
0
BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, const BN_MONT_CTX *from) {
155
0
  if (to == from) {
156
0
    return to;
157
0
  }
158
159
0
  if (!BN_copy(&to->RR, &from->RR) ||
160
0
      !BN_copy(&to->N, &from->N)) {
161
0
    return NULL;
162
0
  }
163
0
  to->n0[0] = from->n0[0];
164
0
  to->n0[1] = from->n0[1];
165
0
  return to;
166
0
}
167
168
914
static int bn_mont_ctx_set_N_and_n0(BN_MONT_CTX *mont, const BIGNUM *mod) {
169
914
  if (BN_is_zero(mod)) {
170
17
    OPENSSL_PUT_ERROR(BN, BN_R_DIV_BY_ZERO);
171
17
    return 0;
172
17
  }
173
897
  if (!BN_is_odd(mod)) {
174
26
    OPENSSL_PUT_ERROR(BN, BN_R_CALLED_WITH_EVEN_MODULUS);
175
26
    return 0;
176
26
  }
177
871
  if (BN_is_negative(mod)) {
178
0
    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
179
0
    return 0;
180
0
  }
181
871
  if (!bn_fits_in_words(mod, BN_MONTGOMERY_MAX_WORDS)) {
182
0
    OPENSSL_PUT_ERROR(BN, BN_R_BIGNUM_TOO_LONG);
183
0
    return 0;
184
0
  }
185
186
  // Save the modulus.
187
871
  if (!BN_copy(&mont->N, mod)) {
188
0
    OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
189
0
    return 0;
190
0
  }
191
  // |mont->N| is always stored minimally. Computing RR efficiently leaks the
192
  // size of the modulus. While the modulus may be private in RSA (one of the
193
  // primes), their sizes are public, so this is fine.
194
871
  bn_set_minimal_width(&mont->N);
195
196
  // Find n0 such that n0 * N == -1 (mod r).
197
  //
198
  // Only certain BN_BITS2<=32 platforms actually make use of n0[1]. For the
199
  // others, we could use a shorter R value and use faster |BN_ULONG|-based
200
  // math instead of |uint64_t|-based math, which would be double-precision.
201
  // However, currently only the assembler files know which is which.
202
871
  static_assert(BN_MONT_CTX_N0_LIMBS == 1 || BN_MONT_CTX_N0_LIMBS == 2,
203
871
                "BN_MONT_CTX_N0_LIMBS value is invalid");
204
871
  static_assert(sizeof(BN_ULONG) * BN_MONT_CTX_N0_LIMBS == sizeof(uint64_t),
205
871
                "uint64_t is insufficient precision for n0");
206
871
  uint64_t n0 = bn_mont_n0(&mont->N);
207
871
  mont->n0[0] = (BN_ULONG)n0;
208
#if BN_MONT_CTX_N0_LIMBS == 2
209
  mont->n0[1] = (BN_ULONG)(n0 >> BN_BITS2);
210
#else
211
871
  mont->n0[1] = 0;
212
871
#endif
213
871
  return 1;
214
871
}
215
216
116
int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) {
217
116
  if (!bn_mont_ctx_set_N_and_n0(mont, mod)) {
218
43
    return 0;
219
43
  }
220
221
73
  BN_CTX *new_ctx = NULL;
222
73
  if (ctx == NULL) {
223
0
    new_ctx = BN_CTX_new();
224
0
    if (new_ctx == NULL) {
225
0
      return 0;
226
0
    }
227
0
    ctx = new_ctx;
228
0
  }
229
230
  // Save RR = R**2 (mod N). R is the smallest power of 2**BN_BITS2 such that R
231
  // > mod. Even though the assembly on some 32-bit platforms works with 64-bit
232
  // values, using |BN_BITS2| here, rather than |BN_MONT_CTX_N0_LIMBS *
233
  // BN_BITS2|, is correct because R**2 will still be a multiple of the latter
234
  // as |BN_MONT_CTX_N0_LIMBS| is either one or two.
235
73
  unsigned lgBigR = mont->N.width * BN_BITS2;
236
73
  BN_zero(&mont->RR);
237
73
  int ok = BN_set_bit(&mont->RR, lgBigR * 2) &&
238
73
           BN_mod(&mont->RR, &mont->RR, &mont->N, ctx) &&
239
73
           bn_resize_words(&mont->RR, mont->N.width);
240
73
  BN_CTX_free(new_ctx);
241
73
  return ok;
242
73
}
243
244
76
BN_MONT_CTX *BN_MONT_CTX_new_for_modulus(const BIGNUM *mod, BN_CTX *ctx) {
245
76
  BN_MONT_CTX *mont = BN_MONT_CTX_new();
246
76
  if (mont == NULL ||
247
76
      !BN_MONT_CTX_set(mont, mod, ctx)) {
248
11
    BN_MONT_CTX_free(mont);
249
11
    return NULL;
250
11
  }
251
65
  return mont;
252
76
}
253
254
798
BN_MONT_CTX *BN_MONT_CTX_new_consttime(const BIGNUM *mod, BN_CTX *ctx) {
255
798
  BN_MONT_CTX *mont = BN_MONT_CTX_new();
256
798
  if (mont == NULL ||
257
798
      !bn_mont_ctx_set_N_and_n0(mont, mod) ||
258
798
      !bn_mont_ctx_set_RR_consttime(mont, ctx)) {
259
0
    BN_MONT_CTX_free(mont);
260
0
    return NULL;
261
0
  }
262
798
  return mont;
263
798
}
264
265
int BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_MUTEX *lock,
266
59
                           const BIGNUM *mod, BN_CTX *bn_ctx) {
267
59
  CRYPTO_MUTEX_lock_read(lock);
268
59
  BN_MONT_CTX *ctx = *pmont;
269
59
  CRYPTO_MUTEX_unlock_read(lock);
270
271
59
  if (ctx) {
272
0
    return 1;
273
0
  }
274
275
59
  CRYPTO_MUTEX_lock_write(lock);
276
59
  if (*pmont == NULL) {
277
59
    *pmont = BN_MONT_CTX_new_for_modulus(mod, bn_ctx);
278
59
  }
279
59
  const int ok = *pmont != NULL;
280
59
  CRYPTO_MUTEX_unlock_write(lock);
281
59
  return ok;
282
59
}
283
284
int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a, const BN_MONT_CTX *mont,
285
22.7k
                     BN_CTX *ctx) {
286
22.7k
  return BN_mod_mul_montgomery(ret, a, &mont->RR, mont, ctx);
287
22.7k
}
288
289
static int bn_from_montgomery_in_place(BN_ULONG *r, size_t num_r, BN_ULONG *a,
290
2.47M
                                       size_t num_a, const BN_MONT_CTX *mont) {
291
2.47M
  const BN_ULONG *n = mont->N.d;
292
2.47M
  size_t num_n = mont->N.width;
293
2.47M
  if (num_r != num_n || num_a != 2 * num_n) {
294
0
    OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
295
0
    return 0;
296
0
  }
297
298
  // Add multiples of |n| to |r| until R = 2^(nl * BN_BITS2) divides it. On
299
  // input, we had |r| < |n| * R, so now |r| < 2 * |n| * R. Note that |r|
300
  // includes |carry| which is stored separately.
301
2.47M
  BN_ULONG n0 = mont->n0[0];
302
2.47M
  BN_ULONG carry = 0;
303
37.2M
  for (size_t i = 0; i < num_n; i++) {
304
34.8M
    BN_ULONG v = bn_mul_add_words(a + i, n, num_n, a[i] * n0);
305
34.8M
    v += carry + a[i + num_n];
306
34.8M
    carry |= (v != a[i + num_n]);
307
34.8M
    carry &= (v <= a[i + num_n]);
308
34.8M
    a[i + num_n] = v;
309
34.8M
  }
310
311
  // Shift |num_n| words to divide by R. We have |a| < 2 * |n|. Note that |a|
312
  // includes |carry| which is stored separately.
313
2.47M
  a += num_n;
314
315
  // |a| thus requires at most one additional subtraction |n| to be reduced.
316
2.47M
  bn_reduce_once(r, a, carry, n, num_n);
317
2.47M
  return 1;
318
2.47M
}
319
320
static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r,
321
2.26M
                                   const BN_MONT_CTX *mont) {
322
2.26M
  if (r->neg) {
323
0
    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
324
0
    return 0;
325
0
  }
326
327
2.26M
  const BIGNUM *n = &mont->N;
328
2.26M
  if (n->width == 0) {
329
0
    ret->width = 0;
330
0
    return 1;
331
0
  }
332
333
2.26M
  int max = 2 * n->width;  // carry is stored separately
334
2.26M
  if (!bn_resize_words(r, max) ||
335
2.26M
      !bn_wexpand(ret, n->width)) {
336
0
    return 0;
337
0
  }
338
339
2.26M
  ret->width = n->width;
340
2.26M
  ret->neg = 0;
341
2.26M
  return bn_from_montgomery_in_place(ret->d, ret->width, r->d, r->width, mont);
342
2.26M
}
343
344
int BN_from_montgomery(BIGNUM *r, const BIGNUM *a, const BN_MONT_CTX *mont,
345
7.75k
                       BN_CTX *ctx) {
346
7.75k
  int ret = 0;
347
7.75k
  BIGNUM *t;
348
349
7.75k
  BN_CTX_start(ctx);
350
7.75k
  t = BN_CTX_get(ctx);
351
7.75k
  if (t == NULL ||
352
7.75k
      !BN_copy(t, a)) {
353
0
    goto err;
354
0
  }
355
356
7.75k
  ret = BN_from_montgomery_word(r, t, mont);
357
358
7.75k
err:
359
7.75k
  BN_CTX_end(ctx);
360
361
7.75k
  return ret;
362
7.75k
}
363
364
4.66k
int bn_one_to_montgomery(BIGNUM *r, const BN_MONT_CTX *mont, BN_CTX *ctx) {
365
  // If the high bit of |n| is set, R = 2^(width*BN_BITS2) < 2 * |n|, so we
366
  // compute R - |n| rather than perform Montgomery reduction.
367
4.66k
  const BIGNUM *n = &mont->N;
368
4.66k
  if (n->width > 0 && (n->d[n->width - 1] >> (BN_BITS2 - 1)) != 0) {
369
1.16k
    if (!bn_wexpand(r, n->width)) {
370
0
      return 0;
371
0
    }
372
1.16k
    r->d[0] = 0 - n->d[0];
373
15.6k
    for (int i = 1; i < n->width; i++) {
374
14.5k
      r->d[i] = ~n->d[i];
375
14.5k
    }
376
1.16k
    r->width = n->width;
377
1.16k
    r->neg = 0;
378
1.16k
    return 1;
379
1.16k
  }
380
381
3.49k
  return BN_from_montgomery(r, &mont->RR, mont, ctx);
382
4.66k
}
383
384
static int bn_mod_mul_montgomery_fallback(BIGNUM *r, const BIGNUM *a,
385
                                          const BIGNUM *b,
386
                                          const BN_MONT_CTX *mont,
387
2.25M
                                          BN_CTX *ctx) {
388
2.25M
  int ret = 0;
389
390
2.25M
  BN_CTX_start(ctx);
391
2.25M
  BIGNUM *tmp = BN_CTX_get(ctx);
392
2.25M
  if (tmp == NULL) {
393
0
    goto err;
394
0
  }
395
396
2.25M
  if (a == b) {
397
1.92M
    if (!bn_sqr_consttime(tmp, a, ctx)) {
398
0
      goto err;
399
0
    }
400
1.92M
  } else {
401
325k
    if (!bn_mul_consttime(tmp, a, b, ctx)) {
402
0
      goto err;
403
0
    }
404
325k
  }
405
406
  // reduce from aRR to aR
407
2.25M
  if (!BN_from_montgomery_word(r, tmp, mont)) {
408
0
    goto err;
409
0
  }
410
411
2.25M
  ret = 1;
412
413
2.25M
err:
414
2.25M
  BN_CTX_end(ctx);
415
2.25M
  return ret;
416
2.25M
}
417
418
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
419
2.62M
                          const BN_MONT_CTX *mont, BN_CTX *ctx) {
420
2.62M
  if (a->neg || b->neg) {
421
0
    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
422
0
    return 0;
423
0
  }
424
425
#if defined(OPENSSL_BN_ASM_MONT)
426
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
427
372k
  int num = mont->N.width;
428
372k
  if (num >= (128 / BN_BITS2) &&
429
372k
      a->width == num &&
430
372k
      b->width == num) {
431
371k
    if (!bn_wexpand(r, num)) {
432
0
      return 0;
433
0
    }
434
    // This bound is implied by |bn_mont_ctx_set_N_and_n0|. |bn_mul_mont|
435
    // allocates |num| words on the stack, so |num| cannot be too large.
436
371k
    assert((size_t)num <= BN_MONTGOMERY_MAX_WORDS);
437
371k
    if (!bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
438
      // The check above ensures this won't happen.
439
0
      assert(0);
440
0
      OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
441
0
      return 0;
442
0
    }
443
371k
    r->neg = 0;
444
371k
    r->width = num;
445
371k
    return 1;
446
371k
  }
447
426
#endif
448
449
2.25M
  return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
450
372k
}
BN_mod_mul_montgomery
Line
Count
Source
419
2.25M
                          const BN_MONT_CTX *mont, BN_CTX *ctx) {
420
2.25M
  if (a->neg || b->neg) {
421
0
    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
422
0
    return 0;
423
0
  }
424
425
#if defined(OPENSSL_BN_ASM_MONT)
426
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
427
  int num = mont->N.width;
428
  if (num >= (128 / BN_BITS2) &&
429
      a->width == num &&
430
      b->width == num) {
431
    if (!bn_wexpand(r, num)) {
432
      return 0;
433
    }
434
    // This bound is implied by |bn_mont_ctx_set_N_and_n0|. |bn_mul_mont|
435
    // allocates |num| words on the stack, so |num| cannot be too large.
436
    assert((size_t)num <= BN_MONTGOMERY_MAX_WORDS);
437
    if (!bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
438
      // The check above ensures this won't happen.
439
      assert(0);
440
      OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
441
      return 0;
442
    }
443
    r->neg = 0;
444
    r->width = num;
445
    return 1;
446
  }
447
#endif
448
449
2.25M
  return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
450
2.25M
}
BN_mod_mul_montgomery
Line
Count
Source
419
372k
                          const BN_MONT_CTX *mont, BN_CTX *ctx) {
420
372k
  if (a->neg || b->neg) {
421
0
    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
422
0
    return 0;
423
0
  }
424
425
372k
#if defined(OPENSSL_BN_ASM_MONT)
426
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
427
372k
  int num = mont->N.width;
428
372k
  if (num >= (128 / BN_BITS2) &&
429
372k
      a->width == num &&
430
372k
      b->width == num) {
431
371k
    if (!bn_wexpand(r, num)) {
432
0
      return 0;
433
0
    }
434
    // This bound is implied by |bn_mont_ctx_set_N_and_n0|. |bn_mul_mont|
435
    // allocates |num| words on the stack, so |num| cannot be too large.
436
371k
    assert((size_t)num <= BN_MONTGOMERY_MAX_WORDS);
437
371k
    if (!bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
438
      // The check above ensures this won't happen.
439
0
      assert(0);
440
0
      OPENSSL_PUT_ERROR(BN, ERR_R_INTERNAL_ERROR);
441
0
      return 0;
442
0
    }
443
371k
    r->neg = 0;
444
371k
    r->width = num;
445
371k
    return 1;
446
371k
  }
447
426
#endif
448
449
426
  return bn_mod_mul_montgomery_fallback(r, a, b, mont, ctx);
450
372k
}
451
452
0
int bn_less_than_montgomery_R(const BIGNUM *bn, const BN_MONT_CTX *mont) {
453
0
  return !BN_is_negative(bn) &&
454
0
         bn_fits_in_words(bn, mont->N.width);
455
0
}
456
457
void bn_to_montgomery_small(BN_ULONG *r, const BN_ULONG *a, size_t num,
458
565
                            const BN_MONT_CTX *mont) {
459
565
  bn_mod_mul_montgomery_small(r, a, mont->RR.d, num, mont);
460
565
}
461
462
void bn_from_montgomery_small(BN_ULONG *r, size_t num_r, const BN_ULONG *a,
463
161
                              size_t num_a, const BN_MONT_CTX *mont) {
464
161
  if (num_r != (size_t)mont->N.width || num_r > BN_SMALL_MAX_WORDS ||
465
161
      num_a > 2 * num_r) {
466
0
    abort();
467
0
  }
468
161
  BN_ULONG tmp[BN_SMALL_MAX_WORDS * 2] = {0};
469
161
  OPENSSL_memcpy(tmp, a, num_a * sizeof(BN_ULONG));
470
161
  if (!bn_from_montgomery_in_place(r, num_r, tmp, 2 * num_r, mont)) {
471
0
    abort();
472
0
  }
473
161
  OPENSSL_cleanse(tmp, 2 * num_r * sizeof(BN_ULONG));
474
161
}
475
476
void bn_mod_mul_montgomery_small(BN_ULONG *r, const BN_ULONG *a,
477
                                 const BN_ULONG *b, size_t num,
478
269k
                                 const BN_MONT_CTX *mont) {
479
269k
  if (num != (size_t)mont->N.width || num > BN_SMALL_MAX_WORDS) {
480
0
    abort();
481
0
  }
482
483
#if defined(OPENSSL_BN_ASM_MONT)
484
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
485
59.6k
  if (num >= (128 / BN_BITS2)) {
486
59.6k
    if (!bn_mul_mont(r, a, b, mont->N.d, mont->n0, num)) {
487
0
      abort();  // The check above ensures this won't happen.
488
0
    }
489
59.6k
    return;
490
59.6k
  }
491
0
#endif
492
493
  // Compute the product.
494
209k
  BN_ULONG tmp[2 * BN_SMALL_MAX_WORDS];
495
209k
  if (a == b) {
496
115k
    bn_sqr_small(tmp, 2 * num, a, num);
497
115k
  } else {
498
94.0k
    bn_mul_small(tmp, 2 * num, a, num, b, num);
499
94.0k
  }
500
501
  // Reduce.
502
209k
  if (!bn_from_montgomery_in_place(r, num, tmp, 2 * num, mont)) {
503
0
    abort();
504
0
  }
505
209k
  OPENSSL_cleanse(tmp, 2 * num * sizeof(BN_ULONG));
506
209k
}
bn_mod_mul_montgomery_small
Line
Count
Source
478
209k
                                 const BN_MONT_CTX *mont) {
479
209k
  if (num != (size_t)mont->N.width || num > BN_SMALL_MAX_WORDS) {
480
0
    abort();
481
0
  }
482
483
#if defined(OPENSSL_BN_ASM_MONT)
484
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
485
  if (num >= (128 / BN_BITS2)) {
486
    if (!bn_mul_mont(r, a, b, mont->N.d, mont->n0, num)) {
487
      abort();  // The check above ensures this won't happen.
488
    }
489
    return;
490
  }
491
#endif
492
493
  // Compute the product.
494
209k
  BN_ULONG tmp[2 * BN_SMALL_MAX_WORDS];
495
209k
  if (a == b) {
496
115k
    bn_sqr_small(tmp, 2 * num, a, num);
497
115k
  } else {
498
94.0k
    bn_mul_small(tmp, 2 * num, a, num, b, num);
499
94.0k
  }
500
501
  // Reduce.
502
209k
  if (!bn_from_montgomery_in_place(r, num, tmp, 2 * num, mont)) {
503
0
    abort();
504
0
  }
505
209k
  OPENSSL_cleanse(tmp, 2 * num * sizeof(BN_ULONG));
506
209k
}
bn_mod_mul_montgomery_small
Line
Count
Source
478
59.6k
                                 const BN_MONT_CTX *mont) {
479
59.6k
  if (num != (size_t)mont->N.width || num > BN_SMALL_MAX_WORDS) {
480
0
    abort();
481
0
  }
482
483
59.6k
#if defined(OPENSSL_BN_ASM_MONT)
484
  // |bn_mul_mont| requires at least 128 bits of limbs, at least for x86.
485
59.6k
  if (num >= (128 / BN_BITS2)) {
486
59.6k
    if (!bn_mul_mont(r, a, b, mont->N.d, mont->n0, num)) {
487
0
      abort();  // The check above ensures this won't happen.
488
0
    }
489
59.6k
    return;
490
59.6k
  }
491
0
#endif
492
493
  // Compute the product.
494
0
  BN_ULONG tmp[2 * BN_SMALL_MAX_WORDS];
495
0
  if (a == b) {
496
0
    bn_sqr_small(tmp, 2 * num, a, num);
497
0
  } else {
498
0
    bn_mul_small(tmp, 2 * num, a, num, b, num);
499
0
  }
500
501
  // Reduce.
502
0
  if (!bn_from_montgomery_in_place(r, num, tmp, 2 * num, mont)) {
503
0
    abort();
504
0
  }
505
0
  OPENSSL_cleanse(tmp, 2 * num * sizeof(BN_ULONG));
506
0
}
507
508
#if defined(OPENSSL_BN_ASM_MONT) && defined(OPENSSL_X86_64)
509
int bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
510
599k
                const BN_ULONG *np, const BN_ULONG *n0, size_t num) {
511
599k
  if (ap == bp && bn_sqr8x_mont_capable(num)) {
512
8.98k
    return bn_sqr8x_mont(rp, ap, bn_mulx_adx_capable(), np, n0, num);
513
8.98k
  }
514
590k
  if (bn_mulx4x_mont_capable(num)) {
515
2.04k
    return bn_mulx4x_mont(rp, ap, bp, np, n0, num);
516
2.04k
  }
517
588k
  if (bn_mul4x_mont_capable(num)) {
518
0
    return bn_mul4x_mont(rp, ap, bp, np, n0, num);
519
0
  }
520
588k
  return bn_mul_mont_nohw(rp, ap, bp, np, n0, num);
521
588k
}
522
#endif
523
524
#if defined(OPENSSL_BN_ASM_MONT) && defined(OPENSSL_ARM)
525
int bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
526
                const BN_ULONG *np, const BN_ULONG *n0, size_t num) {
527
  if (bn_mul8x_mont_neon_capable(num)) {
528
    return bn_mul8x_mont_neon(rp, ap, bp, np, n0, num);
529
  }
530
  return bn_mul_mont_nohw(rp, ap, bp, np, n0, num);
531
}
532
#endif