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58964a49 | 1 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
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. | |
0f113f3e | 7 | * |
d02b48c6 RE |
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). | |
0f113f3e | 14 | * |
d02b48c6 RE |
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. | |
0f113f3e | 21 | * |
d02b48c6 RE |
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 :-). | |
0f113f3e | 36 | * 4. If you include any Windows specific code (or a derivative thereof) from |
d02b48c6 RE |
37 | * the apps directory (application code) you must include an acknowledgement: |
38 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
0f113f3e | 39 | * |
d02b48c6 RE |
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. | |
0f113f3e | 51 | * |
d02b48c6 RE |
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 | */ | |
675f605d BM |
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 | |
0f113f3e | 65 | * notice, this list of conditions and the following disclaimer. |
675f605d BM |
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 | */ | |
d02b48c6 | 110 | |
1b3b0a54 | 111 | /* |
b99b1107 BM |
112 | * Details about Montgomery multiplication algorithms can be found at |
113 | * http://security.ece.orst.edu/publications.html, e.g. | |
114 | * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and | |
115 | * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf | |
1b3b0a54 RE |
116 | */ |
117 | ||
b39fc560 | 118 | #include "internal/cryptlib.h" |
d02b48c6 RE |
119 | #include "bn_lcl.h" |
120 | ||
0f113f3e | 121 | #define MONT_WORD /* use the faster word-based algorithm */ |
6535eb17 | 122 | |
9b4eab50 AP |
123 | #ifdef MONT_WORD |
124 | static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); | |
125 | #endif | |
126 | ||
020fc820 | 127 | int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, |
0f113f3e MC |
128 | BN_MONT_CTX *mont, BN_CTX *ctx) |
129 | { | |
130 | BIGNUM *tmp; | |
131 | int ret = 0; | |
9b4eab50 | 132 | #if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD) |
0f113f3e MC |
133 | int num = mont->N.top; |
134 | ||
135 | if (num > 1 && a->top == num && b->top == num) { | |
136 | if (bn_wexpand(r, num) == NULL) | |
137 | return (0); | |
138 | if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) { | |
139 | r->neg = a->neg ^ b->neg; | |
140 | r->top = num; | |
141 | bn_correct_top(r); | |
142 | return (1); | |
143 | } | |
144 | } | |
e7382805 | 145 | #endif |
dfeab068 | 146 | |
0f113f3e MC |
147 | BN_CTX_start(ctx); |
148 | tmp = BN_CTX_get(ctx); | |
149 | if (tmp == NULL) | |
150 | goto err; | |
151 | ||
152 | bn_check_top(tmp); | |
153 | if (a == b) { | |
154 | if (!BN_sqr(tmp, a, ctx)) | |
155 | goto err; | |
156 | } else { | |
157 | if (!BN_mul(tmp, a, b, ctx)) | |
158 | goto err; | |
159 | } | |
160 | /* reduce from aRR to aR */ | |
9b4eab50 | 161 | #ifdef MONT_WORD |
0f113f3e MC |
162 | if (!BN_from_montgomery_word(r, tmp, mont)) |
163 | goto err; | |
9b4eab50 | 164 | #else |
0f113f3e MC |
165 | if (!BN_from_montgomery(r, tmp, mont, ctx)) |
166 | goto err; | |
9b4eab50 | 167 | #endif |
0f113f3e MC |
168 | bn_check_top(r); |
169 | ret = 1; | |
170 | err: | |
171 | BN_CTX_end(ctx); | |
172 | return (ret); | |
173 | } | |
d02b48c6 | 174 | |
6535eb17 | 175 | #ifdef MONT_WORD |
9b4eab50 | 176 | static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) |
0f113f3e MC |
177 | { |
178 | BIGNUM *n; | |
179 | BN_ULONG *ap, *np, *rp, n0, v, carry; | |
180 | int nl, max, i; | |
181 | ||
182 | n = &(mont->N); | |
183 | nl = n->top; | |
184 | if (nl == 0) { | |
185 | ret->top = 0; | |
186 | return (1); | |
187 | } | |
188 | ||
189 | max = (2 * nl); /* carry is stored separately */ | |
190 | if (bn_wexpand(r, max) == NULL) | |
191 | return (0); | |
192 | ||
193 | r->neg ^= n->neg; | |
194 | np = n->d; | |
195 | rp = r->d; | |
196 | ||
197 | /* clear the top words of T */ | |
9f040d6d RS |
198 | i = max - r->top; |
199 | if (i) | |
200 | memset(&rp[r->top], 0, sizeof(*rp) * i); | |
0f113f3e MC |
201 | |
202 | r->top = max; | |
203 | n0 = mont->n0[0]; | |
204 | ||
205 | for (carry = 0, i = 0; i < nl; i++, rp++) { | |
206 | v = bn_mul_add_words(rp, np, nl, (rp[0] * n0) & BN_MASK2); | |
207 | v = (v + carry + rp[nl]) & BN_MASK2; | |
208 | carry |= (v != rp[nl]); | |
209 | carry &= (v <= rp[nl]); | |
210 | rp[nl] = v; | |
211 | } | |
212 | ||
213 | if (bn_wexpand(ret, nl) == NULL) | |
214 | return (0); | |
215 | ret->top = nl; | |
216 | ret->neg = r->neg; | |
217 | ||
218 | rp = ret->d; | |
219 | ap = &(r->d[nl]); | |
220 | ||
221 | # define BRANCH_FREE 1 | |
222 | # if BRANCH_FREE | |
223 | { | |
224 | BN_ULONG *nrp; | |
225 | size_t m; | |
226 | ||
227 | v = bn_sub_words(rp, ap, np, nl) - carry; | |
228 | /* | |
229 | * if subtraction result is real, then trick unconditional memcpy | |
230 | * below to perform in-place "refresh" instead of actual copy. | |
231 | */ | |
232 | m = (0 - (size_t)v); | |
233 | nrp = | |
234 | (BN_ULONG *)(((PTR_SIZE_INT) rp & ~m) | ((PTR_SIZE_INT) ap & m)); | |
235 | ||
236 | for (i = 0, nl -= 4; i < nl; i += 4) { | |
237 | BN_ULONG t1, t2, t3, t4; | |
238 | ||
239 | t1 = nrp[i + 0]; | |
240 | t2 = nrp[i + 1]; | |
241 | t3 = nrp[i + 2]; | |
242 | ap[i + 0] = 0; | |
243 | t4 = nrp[i + 3]; | |
244 | ap[i + 1] = 0; | |
245 | rp[i + 0] = t1; | |
246 | ap[i + 2] = 0; | |
247 | rp[i + 1] = t2; | |
248 | ap[i + 3] = 0; | |
249 | rp[i + 2] = t3; | |
250 | rp[i + 3] = t4; | |
251 | } | |
252 | for (nl += 4; i < nl; i++) | |
253 | rp[i] = nrp[i], ap[i] = 0; | |
254 | } | |
255 | # else | |
256 | if (bn_sub_words(rp, ap, np, nl) - carry) | |
257 | memcpy(rp, ap, nl * sizeof(BN_ULONG)); | |
258 | # endif | |
259 | bn_correct_top(r); | |
260 | bn_correct_top(ret); | |
261 | bn_check_top(ret); | |
262 | ||
263 | return (1); | |
264 | } | |
265 | #endif /* MONT_WORD */ | |
9b4eab50 AP |
266 | |
267 | int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, | |
0f113f3e MC |
268 | BN_CTX *ctx) |
269 | { | |
270 | int retn = 0; | |
9b4eab50 | 271 | #ifdef MONT_WORD |
0f113f3e MC |
272 | BIGNUM *t; |
273 | ||
274 | BN_CTX_start(ctx); | |
275 | if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) | |
276 | retn = BN_from_montgomery_word(ret, t, mont); | |
277 | BN_CTX_end(ctx); | |
278 | #else /* !MONT_WORD */ | |
279 | BIGNUM *t1, *t2; | |
280 | ||
281 | BN_CTX_start(ctx); | |
282 | t1 = BN_CTX_get(ctx); | |
283 | t2 = BN_CTX_get(ctx); | |
284 | if (t1 == NULL || t2 == NULL) | |
285 | goto err; | |
286 | ||
287 | if (!BN_copy(t1, a)) | |
288 | goto err; | |
289 | BN_mask_bits(t1, mont->ri); | |
290 | ||
291 | if (!BN_mul(t2, t1, &mont->Ni, ctx)) | |
292 | goto err; | |
293 | BN_mask_bits(t2, mont->ri); | |
294 | ||
295 | if (!BN_mul(t1, t2, &mont->N, ctx)) | |
296 | goto err; | |
297 | if (!BN_add(t2, a, t1)) | |
298 | goto err; | |
299 | if (!BN_rshift(ret, t2, mont->ri)) | |
300 | goto err; | |
301 | ||
302 | if (BN_ucmp(ret, &(mont->N)) >= 0) { | |
303 | if (!BN_usub(ret, ret, &(mont->N))) | |
304 | goto err; | |
305 | } | |
306 | retn = 1; | |
307 | bn_check_top(ret); | |
e93f9a32 | 308 | err: |
0f113f3e MC |
309 | BN_CTX_end(ctx); |
310 | #endif /* MONT_WORD */ | |
311 | return (retn); | |
312 | } | |
d02b48c6 | 313 | |
6b691a5c | 314 | BN_MONT_CTX *BN_MONT_CTX_new(void) |
0f113f3e MC |
315 | { |
316 | BN_MONT_CTX *ret; | |
d02b48c6 | 317 | |
b4faea50 | 318 | if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) |
0f113f3e | 319 | return (NULL); |
dfeab068 | 320 | |
0f113f3e MC |
321 | BN_MONT_CTX_init(ret); |
322 | ret->flags = BN_FLG_MALLOCED; | |
323 | return (ret); | |
324 | } | |
d02b48c6 | 325 | |
6b691a5c | 326 | void BN_MONT_CTX_init(BN_MONT_CTX *ctx) |
0f113f3e MC |
327 | { |
328 | ctx->ri = 0; | |
d59c7c81 RS |
329 | bn_init(&(ctx->RR)); |
330 | bn_init(&(ctx->N)); | |
331 | bn_init(&(ctx->Ni)); | |
0f113f3e MC |
332 | ctx->n0[0] = ctx->n0[1] = 0; |
333 | ctx->flags = 0; | |
334 | } | |
dfeab068 | 335 | |
6b691a5c | 336 | void BN_MONT_CTX_free(BN_MONT_CTX *mont) |
0f113f3e MC |
337 | { |
338 | if (mont == NULL) | |
339 | return; | |
e03ddfae | 340 | |
1a586b39 LV |
341 | BN_clear_free(&(mont->RR)); |
342 | BN_clear_free(&(mont->N)); | |
343 | BN_clear_free(&(mont->Ni)); | |
0f113f3e MC |
344 | if (mont->flags & BN_FLG_MALLOCED) |
345 | OPENSSL_free(mont); | |
346 | } | |
d02b48c6 | 347 | |
84c15db5 | 348 | int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) |
0f113f3e MC |
349 | { |
350 | int ret = 0; | |
351 | BIGNUM *Ri, *R; | |
352 | ||
6a009812 MC |
353 | if (BN_is_zero(mod)) |
354 | return 0; | |
355 | ||
0f113f3e MC |
356 | BN_CTX_start(ctx); |
357 | if ((Ri = BN_CTX_get(ctx)) == NULL) | |
358 | goto err; | |
359 | R = &(mont->RR); /* grab RR as a temp */ | |
360 | if (!BN_copy(&(mont->N), mod)) | |
361 | goto err; /* Set N */ | |
362 | mont->N.neg = 0; | |
dfeab068 | 363 | |
6535eb17 | 364 | #ifdef MONT_WORD |
0f113f3e MC |
365 | { |
366 | BIGNUM tmod; | |
367 | BN_ULONG buf[2]; | |
368 | ||
d59c7c81 | 369 | bn_init(&tmod); |
0f113f3e MC |
370 | tmod.d = buf; |
371 | tmod.dmax = 2; | |
372 | tmod.neg = 0; | |
373 | ||
374 | mont->ri = (BN_num_bits(mod) + (BN_BITS2 - 1)) / BN_BITS2 * BN_BITS2; | |
375 | ||
376 | # if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) | |
377 | /* | |
378 | * Only certain BN_BITS2<=32 platforms actually make use of n0[1], | |
379 | * and we could use the #else case (with a shorter R value) for the | |
380 | * others. However, currently only the assembler files do know which | |
381 | * is which. | |
382 | */ | |
383 | ||
384 | BN_zero(R); | |
385 | if (!(BN_set_bit(R, 2 * BN_BITS2))) | |
386 | goto err; | |
387 | ||
388 | tmod.top = 0; | |
389 | if ((buf[0] = mod->d[0])) | |
390 | tmod.top = 1; | |
391 | if ((buf[1] = mod->top > 1 ? mod->d[1] : 0)) | |
392 | tmod.top = 2; | |
393 | ||
394 | if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL) | |
395 | goto err; | |
396 | if (!BN_lshift(Ri, Ri, 2 * BN_BITS2)) | |
397 | goto err; /* R*Ri */ | |
398 | if (!BN_is_zero(Ri)) { | |
399 | if (!BN_sub_word(Ri, 1)) | |
400 | goto err; | |
401 | } else { /* if N mod word size == 1 */ | |
402 | ||
403 | if (bn_expand(Ri, (int)sizeof(BN_ULONG) * 2) == NULL) | |
404 | goto err; | |
405 | /* Ri-- (mod double word size) */ | |
406 | Ri->neg = 0; | |
407 | Ri->d[0] = BN_MASK2; | |
408 | Ri->d[1] = BN_MASK2; | |
409 | Ri->top = 2; | |
410 | } | |
411 | if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) | |
412 | goto err; | |
413 | /* | |
414 | * Ni = (R*Ri-1)/N, keep only couple of least significant words: | |
415 | */ | |
416 | mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; | |
417 | mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0; | |
418 | # else | |
419 | BN_zero(R); | |
420 | if (!(BN_set_bit(R, BN_BITS2))) | |
421 | goto err; /* R */ | |
422 | ||
423 | buf[0] = mod->d[0]; /* tmod = N mod word size */ | |
424 | buf[1] = 0; | |
425 | tmod.top = buf[0] != 0 ? 1 : 0; | |
426 | /* Ri = R^-1 mod N */ | |
427 | if ((BN_mod_inverse(Ri, R, &tmod, ctx)) == NULL) | |
428 | goto err; | |
429 | if (!BN_lshift(Ri, Ri, BN_BITS2)) | |
430 | goto err; /* R*Ri */ | |
431 | if (!BN_is_zero(Ri)) { | |
432 | if (!BN_sub_word(Ri, 1)) | |
433 | goto err; | |
434 | } else { /* if N mod word size == 1 */ | |
435 | ||
436 | if (!BN_set_word(Ri, BN_MASK2)) | |
437 | goto err; /* Ri-- (mod word size) */ | |
438 | } | |
439 | if (!BN_div(Ri, NULL, Ri, &tmod, ctx)) | |
440 | goto err; | |
441 | /* | |
442 | * Ni = (R*Ri-1)/N, keep only least significant word: | |
443 | */ | |
444 | mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; | |
445 | mont->n0[1] = 0; | |
446 | # endif | |
447 | } | |
448 | #else /* !MONT_WORD */ | |
449 | { /* bignum version */ | |
450 | mont->ri = BN_num_bits(&mont->N); | |
451 | BN_zero(R); | |
452 | if (!BN_set_bit(R, mont->ri)) | |
453 | goto err; /* R = 2^ri */ | |
454 | /* Ri = R^-1 mod N */ | |
455 | if ((BN_mod_inverse(Ri, R, &mont->N, ctx)) == NULL) | |
456 | goto err; | |
457 | if (!BN_lshift(Ri, Ri, mont->ri)) | |
458 | goto err; /* R*Ri */ | |
459 | if (!BN_sub_word(Ri, 1)) | |
460 | goto err; | |
461 | /* | |
462 | * Ni = (R*Ri-1) / N | |
463 | */ | |
464 | if (!BN_div(&(mont->Ni), NULL, Ri, &mont->N, ctx)) | |
465 | goto err; | |
466 | } | |
d02b48c6 RE |
467 | #endif |
468 | ||
0f113f3e MC |
469 | /* setup RR for conversions */ |
470 | BN_zero(&(mont->RR)); | |
471 | if (!BN_set_bit(&(mont->RR), mont->ri * 2)) | |
472 | goto err; | |
473 | if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx)) | |
474 | goto err; | |
d02b48c6 | 475 | |
0f113f3e MC |
476 | ret = 1; |
477 | err: | |
478 | BN_CTX_end(ctx); | |
479 | return ret; | |
480 | } | |
d02b48c6 | 481 | |
6b691a5c | 482 | BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) |
0f113f3e MC |
483 | { |
484 | if (to == from) | |
485 | return (to); | |
486 | ||
487 | if (!BN_copy(&(to->RR), &(from->RR))) | |
488 | return NULL; | |
489 | if (!BN_copy(&(to->N), &(from->N))) | |
490 | return NULL; | |
491 | if (!BN_copy(&(to->Ni), &(from->Ni))) | |
492 | return NULL; | |
493 | to->ri = from->ri; | |
494 | to->n0[0] = from->n0[0]; | |
495 | to->n0[1] = from->n0[1]; | |
496 | return (to); | |
497 | } | |
dfeab068 | 498 | |
6ec8e63a | 499 | BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock, |
0f113f3e MC |
500 | const BIGNUM *mod, BN_CTX *ctx) |
501 | { | |
502 | BN_MONT_CTX *ret; | |
503 | ||
504 | CRYPTO_r_lock(lock); | |
505 | ret = *pmont; | |
506 | CRYPTO_r_unlock(lock); | |
507 | if (ret) | |
508 | return ret; | |
509 | ||
510 | /* | |
511 | * We don't want to serialise globally while doing our lazy-init math in | |
512 | * BN_MONT_CTX_set. That punishes threads that are doing independent | |
513 | * things. Instead, punish the case where more than one thread tries to | |
514 | * lazy-init the same 'pmont', by having each do the lazy-init math work | |
515 | * independently and only use the one from the thread that wins the race | |
516 | * (the losers throw away the work they've done). | |
517 | */ | |
518 | ret = BN_MONT_CTX_new(); | |
90945fa3 | 519 | if (ret == NULL) |
0f113f3e MC |
520 | return NULL; |
521 | if (!BN_MONT_CTX_set(ret, mod, ctx)) { | |
522 | BN_MONT_CTX_free(ret); | |
523 | return NULL; | |
524 | } | |
525 | ||
526 | /* The locked compare-and-set, after the local work is done. */ | |
527 | CRYPTO_w_lock(lock); | |
528 | if (*pmont) { | |
529 | BN_MONT_CTX_free(ret); | |
530 | ret = *pmont; | |
531 | } else | |
532 | *pmont = ret; | |
533 | CRYPTO_w_unlock(lock); | |
534 | return ret; | |
535 | } |