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4f22f405 RS |
1 | /* |
2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. | |
dcbd0d74 | 3 | * |
4f22f405 RS |
4 | * Licensed under the OpenSSL license (the "License"). You may not use |
5 | * this file except in compliance with the License. You can obtain a copy | |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
dcbd0d74 | 8 | */ |
d02b48c6 | 9 | |
b39fc560 | 10 | #include "internal/cryptlib.h" |
d02b48c6 RE |
11 | #include "bn_lcl.h" |
12 | ||
d02b48c6 | 13 | static BIGNUM *euclid(BIGNUM *a, BIGNUM *b); |
9b141126 | 14 | |
cbd48ba6 | 15 | int BN_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx) |
0f113f3e MC |
16 | { |
17 | BIGNUM *a, *b, *t; | |
18 | int ret = 0; | |
19 | ||
20 | bn_check_top(in_a); | |
21 | bn_check_top(in_b); | |
22 | ||
23 | BN_CTX_start(ctx); | |
24 | a = BN_CTX_get(ctx); | |
25 | b = BN_CTX_get(ctx); | |
26 | if (a == NULL || b == NULL) | |
27 | goto err; | |
28 | ||
29 | if (BN_copy(a, in_a) == NULL) | |
30 | goto err; | |
31 | if (BN_copy(b, in_b) == NULL) | |
32 | goto err; | |
33 | a->neg = 0; | |
34 | b->neg = 0; | |
35 | ||
36 | if (BN_cmp(a, b) < 0) { | |
37 | t = a; | |
38 | a = b; | |
39 | b = t; | |
40 | } | |
41 | t = euclid(a, b); | |
42 | if (t == NULL) | |
43 | goto err; | |
44 | ||
45 | if (BN_copy(r, t) == NULL) | |
46 | goto err; | |
47 | ret = 1; | |
48 | err: | |
49 | BN_CTX_end(ctx); | |
50 | bn_check_top(r); | |
51 | return (ret); | |
52 | } | |
d02b48c6 | 53 | |
6b691a5c | 54 | static BIGNUM *euclid(BIGNUM *a, BIGNUM *b) |
0f113f3e MC |
55 | { |
56 | BIGNUM *t; | |
57 | int shifts = 0; | |
58 | ||
59 | bn_check_top(a); | |
60 | bn_check_top(b); | |
61 | ||
62 | /* 0 <= b <= a */ | |
63 | while (!BN_is_zero(b)) { | |
64 | /* 0 < b <= a */ | |
65 | ||
66 | if (BN_is_odd(a)) { | |
67 | if (BN_is_odd(b)) { | |
68 | if (!BN_sub(a, a, b)) | |
69 | goto err; | |
70 | if (!BN_rshift1(a, a)) | |
71 | goto err; | |
72 | if (BN_cmp(a, b) < 0) { | |
73 | t = a; | |
74 | a = b; | |
75 | b = t; | |
76 | } | |
77 | } else { /* a odd - b even */ | |
78 | ||
79 | if (!BN_rshift1(b, b)) | |
80 | goto err; | |
81 | if (BN_cmp(a, b) < 0) { | |
82 | t = a; | |
83 | a = b; | |
84 | b = t; | |
85 | } | |
86 | } | |
87 | } else { /* a is even */ | |
88 | ||
89 | if (BN_is_odd(b)) { | |
90 | if (!BN_rshift1(a, a)) | |
91 | goto err; | |
92 | if (BN_cmp(a, b) < 0) { | |
93 | t = a; | |
94 | a = b; | |
95 | b = t; | |
96 | } | |
97 | } else { /* a even - b even */ | |
98 | ||
99 | if (!BN_rshift1(a, a)) | |
100 | goto err; | |
101 | if (!BN_rshift1(b, b)) | |
102 | goto err; | |
103 | shifts++; | |
104 | } | |
105 | } | |
106 | /* 0 <= b <= a */ | |
107 | } | |
108 | ||
109 | if (shifts) { | |
110 | if (!BN_lshift(a, a, shifts)) | |
111 | goto err; | |
112 | } | |
113 | bn_check_top(a); | |
114 | return (a); | |
115 | err: | |
116 | return (NULL); | |
117 | } | |
dcbd0d74 | 118 | |
d02b48c6 | 119 | /* solves ax == 1 (mod n) */ |
55525742 | 120 | static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in, |
0f113f3e MC |
121 | const BIGNUM *a, const BIGNUM *n, |
122 | BN_CTX *ctx); | |
879bd6e3 | 123 | |
020fc820 | 124 | BIGNUM *BN_mod_inverse(BIGNUM *in, |
0f113f3e MC |
125 | const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx) |
126 | { | |
127 | BIGNUM *rv; | |
128 | int noinv; | |
129 | rv = int_bn_mod_inverse(in, a, n, ctx, &noinv); | |
130 | if (noinv) | |
131 | BNerr(BN_F_BN_MOD_INVERSE, BN_R_NO_INVERSE); | |
132 | return rv; | |
133 | } | |
879bd6e3 DSH |
134 | |
135 | BIGNUM *int_bn_mod_inverse(BIGNUM *in, | |
0f113f3e MC |
136 | const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx, |
137 | int *pnoinv) | |
138 | { | |
139 | BIGNUM *A, *B, *X, *Y, *M, *D, *T, *R = NULL; | |
140 | BIGNUM *ret = NULL; | |
141 | int sign; | |
142 | ||
143 | if (pnoinv) | |
144 | *pnoinv = 0; | |
145 | ||
146 | if ((BN_get_flags(a, BN_FLG_CONSTTIME) != 0) | |
147 | || (BN_get_flags(n, BN_FLG_CONSTTIME) != 0)) { | |
148 | return BN_mod_inverse_no_branch(in, a, n, ctx); | |
149 | } | |
150 | ||
151 | bn_check_top(a); | |
152 | bn_check_top(n); | |
153 | ||
154 | BN_CTX_start(ctx); | |
155 | A = BN_CTX_get(ctx); | |
156 | B = BN_CTX_get(ctx); | |
157 | X = BN_CTX_get(ctx); | |
158 | D = BN_CTX_get(ctx); | |
159 | M = BN_CTX_get(ctx); | |
160 | Y = BN_CTX_get(ctx); | |
161 | T = BN_CTX_get(ctx); | |
162 | if (T == NULL) | |
163 | goto err; | |
164 | ||
165 | if (in == NULL) | |
166 | R = BN_new(); | |
167 | else | |
168 | R = in; | |
169 | if (R == NULL) | |
170 | goto err; | |
171 | ||
172 | BN_one(X); | |
173 | BN_zero(Y); | |
174 | if (BN_copy(B, a) == NULL) | |
175 | goto err; | |
176 | if (BN_copy(A, n) == NULL) | |
177 | goto err; | |
178 | A->neg = 0; | |
179 | if (B->neg || (BN_ucmp(B, A) >= 0)) { | |
180 | if (!BN_nnmod(B, B, A, ctx)) | |
181 | goto err; | |
182 | } | |
183 | sign = -1; | |
50e735f9 MC |
184 | /*- |
185 | * From B = a mod |n|, A = |n| it follows that | |
186 | * | |
187 | * 0 <= B < A, | |
188 | * -sign*X*a == B (mod |n|), | |
189 | * sign*Y*a == A (mod |n|). | |
190 | */ | |
0f113f3e | 191 | |
94af0cd7 | 192 | if (BN_is_odd(n) && (BN_num_bits(n) <= 2048)) { |
0f113f3e MC |
193 | /* |
194 | * Binary inversion algorithm; requires odd modulus. This is faster | |
195 | * than the general algorithm if the modulus is sufficiently small | |
0d4fb843 | 196 | * (about 400 .. 500 bits on 32-bit systems, but much more on 64-bit |
0f113f3e MC |
197 | * systems) |
198 | */ | |
199 | int shift; | |
200 | ||
201 | while (!BN_is_zero(B)) { | |
50e735f9 MC |
202 | /*- |
203 | * 0 < B < |n|, | |
204 | * 0 < A <= |n|, | |
205 | * (1) -sign*X*a == B (mod |n|), | |
206 | * (2) sign*Y*a == A (mod |n|) | |
207 | */ | |
0f113f3e MC |
208 | |
209 | /* | |
210 | * Now divide B by the maximum possible power of two in the | |
211 | * integers, and divide X by the same value mod |n|. When we're | |
212 | * done, (1) still holds. | |
213 | */ | |
214 | shift = 0; | |
215 | while (!BN_is_bit_set(B, shift)) { /* note that 0 < B */ | |
216 | shift++; | |
217 | ||
218 | if (BN_is_odd(X)) { | |
219 | if (!BN_uadd(X, X, n)) | |
220 | goto err; | |
221 | } | |
222 | /* | |
223 | * now X is even, so we can easily divide it by two | |
224 | */ | |
225 | if (!BN_rshift1(X, X)) | |
226 | goto err; | |
227 | } | |
228 | if (shift > 0) { | |
229 | if (!BN_rshift(B, B, shift)) | |
230 | goto err; | |
231 | } | |
232 | ||
233 | /* | |
234 | * Same for A and Y. Afterwards, (2) still holds. | |
235 | */ | |
236 | shift = 0; | |
237 | while (!BN_is_bit_set(A, shift)) { /* note that 0 < A */ | |
238 | shift++; | |
239 | ||
240 | if (BN_is_odd(Y)) { | |
241 | if (!BN_uadd(Y, Y, n)) | |
242 | goto err; | |
243 | } | |
244 | /* now Y is even */ | |
245 | if (!BN_rshift1(Y, Y)) | |
246 | goto err; | |
247 | } | |
248 | if (shift > 0) { | |
249 | if (!BN_rshift(A, A, shift)) | |
250 | goto err; | |
251 | } | |
252 | ||
50e735f9 MC |
253 | /*- |
254 | * We still have (1) and (2). | |
255 | * Both A and B are odd. | |
256 | * The following computations ensure that | |
257 | * | |
258 | * 0 <= B < |n|, | |
259 | * 0 < A < |n|, | |
260 | * (1) -sign*X*a == B (mod |n|), | |
261 | * (2) sign*Y*a == A (mod |n|), | |
262 | * | |
263 | * and that either A or B is even in the next iteration. | |
264 | */ | |
0f113f3e MC |
265 | if (BN_ucmp(B, A) >= 0) { |
266 | /* -sign*(X + Y)*a == B - A (mod |n|) */ | |
267 | if (!BN_uadd(X, X, Y)) | |
268 | goto err; | |
269 | /* | |
270 | * NB: we could use BN_mod_add_quick(X, X, Y, n), but that | |
271 | * actually makes the algorithm slower | |
272 | */ | |
273 | if (!BN_usub(B, B, A)) | |
274 | goto err; | |
275 | } else { | |
276 | /* sign*(X + Y)*a == A - B (mod |n|) */ | |
277 | if (!BN_uadd(Y, Y, X)) | |
278 | goto err; | |
279 | /* | |
280 | * as above, BN_mod_add_quick(Y, Y, X, n) would slow things | |
281 | * down | |
282 | */ | |
283 | if (!BN_usub(A, A, B)) | |
284 | goto err; | |
285 | } | |
286 | } | |
287 | } else { | |
288 | /* general inversion algorithm */ | |
289 | ||
290 | while (!BN_is_zero(B)) { | |
291 | BIGNUM *tmp; | |
292 | ||
50e735f9 MC |
293 | /*- |
294 | * 0 < B < A, | |
295 | * (*) -sign*X*a == B (mod |n|), | |
296 | * sign*Y*a == A (mod |n|) | |
297 | */ | |
0f113f3e MC |
298 | |
299 | /* (D, M) := (A/B, A%B) ... */ | |
300 | if (BN_num_bits(A) == BN_num_bits(B)) { | |
301 | if (!BN_one(D)) | |
302 | goto err; | |
303 | if (!BN_sub(M, A, B)) | |
304 | goto err; | |
305 | } else if (BN_num_bits(A) == BN_num_bits(B) + 1) { | |
306 | /* A/B is 1, 2, or 3 */ | |
307 | if (!BN_lshift1(T, B)) | |
308 | goto err; | |
309 | if (BN_ucmp(A, T) < 0) { | |
310 | /* A < 2*B, so D=1 */ | |
311 | if (!BN_one(D)) | |
312 | goto err; | |
313 | if (!BN_sub(M, A, B)) | |
314 | goto err; | |
315 | } else { | |
316 | /* A >= 2*B, so D=2 or D=3 */ | |
317 | if (!BN_sub(M, A, T)) | |
318 | goto err; | |
319 | if (!BN_add(D, T, B)) | |
320 | goto err; /* use D (:= 3*B) as temp */ | |
321 | if (BN_ucmp(A, D) < 0) { | |
322 | /* A < 3*B, so D=2 */ | |
323 | if (!BN_set_word(D, 2)) | |
324 | goto err; | |
325 | /* | |
326 | * M (= A - 2*B) already has the correct value | |
327 | */ | |
328 | } else { | |
329 | /* only D=3 remains */ | |
330 | if (!BN_set_word(D, 3)) | |
331 | goto err; | |
332 | /* | |
333 | * currently M = A - 2*B, but we need M = A - 3*B | |
334 | */ | |
335 | if (!BN_sub(M, M, B)) | |
336 | goto err; | |
337 | } | |
338 | } | |
339 | } else { | |
340 | if (!BN_div(D, M, A, B, ctx)) | |
341 | goto err; | |
342 | } | |
343 | ||
50e735f9 MC |
344 | /*- |
345 | * Now | |
346 | * A = D*B + M; | |
347 | * thus we have | |
348 | * (**) sign*Y*a == D*B + M (mod |n|). | |
349 | */ | |
0f113f3e MC |
350 | |
351 | tmp = A; /* keep the BIGNUM object, the value does not | |
352 | * matter */ | |
353 | ||
354 | /* (A, B) := (B, A mod B) ... */ | |
355 | A = B; | |
356 | B = M; | |
357 | /* ... so we have 0 <= B < A again */ | |
358 | ||
50e735f9 MC |
359 | /*- |
360 | * Since the former M is now B and the former B is now A, | |
361 | * (**) translates into | |
362 | * sign*Y*a == D*A + B (mod |n|), | |
363 | * i.e. | |
364 | * sign*Y*a - D*A == B (mod |n|). | |
365 | * Similarly, (*) translates into | |
366 | * -sign*X*a == A (mod |n|). | |
367 | * | |
368 | * Thus, | |
369 | * sign*Y*a + D*sign*X*a == B (mod |n|), | |
370 | * i.e. | |
371 | * sign*(Y + D*X)*a == B (mod |n|). | |
372 | * | |
373 | * So if we set (X, Y, sign) := (Y + D*X, X, -sign), we arrive back at | |
374 | * -sign*X*a == B (mod |n|), | |
375 | * sign*Y*a == A (mod |n|). | |
376 | * Note that X and Y stay non-negative all the time. | |
377 | */ | |
0f113f3e MC |
378 | |
379 | /* | |
380 | * most of the time D is very small, so we can optimize tmp := | |
381 | * D*X+Y | |
382 | */ | |
383 | if (BN_is_one(D)) { | |
384 | if (!BN_add(tmp, X, Y)) | |
385 | goto err; | |
386 | } else { | |
387 | if (BN_is_word(D, 2)) { | |
388 | if (!BN_lshift1(tmp, X)) | |
389 | goto err; | |
390 | } else if (BN_is_word(D, 4)) { | |
391 | if (!BN_lshift(tmp, X, 2)) | |
392 | goto err; | |
393 | } else if (D->top == 1) { | |
394 | if (!BN_copy(tmp, X)) | |
395 | goto err; | |
396 | if (!BN_mul_word(tmp, D->d[0])) | |
397 | goto err; | |
398 | } else { | |
399 | if (!BN_mul(tmp, D, X, ctx)) | |
400 | goto err; | |
401 | } | |
402 | if (!BN_add(tmp, tmp, Y)) | |
403 | goto err; | |
404 | } | |
405 | ||
406 | M = Y; /* keep the BIGNUM object, the value does not | |
407 | * matter */ | |
408 | Y = X; | |
409 | X = tmp; | |
410 | sign = -sign; | |
411 | } | |
412 | } | |
413 | ||
50e735f9 MC |
414 | /*- |
415 | * The while loop (Euclid's algorithm) ends when | |
416 | * A == gcd(a,n); | |
417 | * we have | |
418 | * sign*Y*a == A (mod |n|), | |
419 | * where Y is non-negative. | |
420 | */ | |
0f113f3e MC |
421 | |
422 | if (sign < 0) { | |
423 | if (!BN_sub(Y, n, Y)) | |
424 | goto err; | |
425 | } | |
426 | /* Now Y*a == A (mod |n|). */ | |
427 | ||
428 | if (BN_is_one(A)) { | |
429 | /* Y*a == 1 (mod |n|) */ | |
430 | if (!Y->neg && BN_ucmp(Y, n) < 0) { | |
431 | if (!BN_copy(R, Y)) | |
432 | goto err; | |
433 | } else { | |
434 | if (!BN_nnmod(R, Y, n, ctx)) | |
435 | goto err; | |
436 | } | |
437 | } else { | |
438 | if (pnoinv) | |
439 | *pnoinv = 1; | |
440 | goto err; | |
441 | } | |
442 | ret = R; | |
443 | err: | |
444 | if ((ret == NULL) && (in == NULL)) | |
445 | BN_free(R); | |
446 | BN_CTX_end(ctx); | |
447 | bn_check_top(ret); | |
448 | return (ret); | |
449 | } | |
450 | ||
451 | /* | |
452 | * BN_mod_inverse_no_branch is a special version of BN_mod_inverse. It does | |
453 | * not contain branches that may leak sensitive information. | |
bd31fb21 | 454 | */ |
55525742 | 455 | static BIGNUM *BN_mod_inverse_no_branch(BIGNUM *in, |
0f113f3e MC |
456 | const BIGNUM *a, const BIGNUM *n, |
457 | BN_CTX *ctx) | |
458 | { | |
459 | BIGNUM *A, *B, *X, *Y, *M, *D, *T, *R = NULL; | |
0f113f3e MC |
460 | BIGNUM *ret = NULL; |
461 | int sign; | |
462 | ||
463 | bn_check_top(a); | |
464 | bn_check_top(n); | |
465 | ||
466 | BN_CTX_start(ctx); | |
467 | A = BN_CTX_get(ctx); | |
468 | B = BN_CTX_get(ctx); | |
469 | X = BN_CTX_get(ctx); | |
470 | D = BN_CTX_get(ctx); | |
471 | M = BN_CTX_get(ctx); | |
472 | Y = BN_CTX_get(ctx); | |
473 | T = BN_CTX_get(ctx); | |
474 | if (T == NULL) | |
475 | goto err; | |
476 | ||
477 | if (in == NULL) | |
478 | R = BN_new(); | |
479 | else | |
480 | R = in; | |
481 | if (R == NULL) | |
482 | goto err; | |
483 | ||
484 | BN_one(X); | |
485 | BN_zero(Y); | |
486 | if (BN_copy(B, a) == NULL) | |
487 | goto err; | |
488 | if (BN_copy(A, n) == NULL) | |
489 | goto err; | |
490 | A->neg = 0; | |
491 | ||
492 | if (B->neg || (BN_ucmp(B, A) >= 0)) { | |
493 | /* | |
494 | * Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked, | |
495 | * BN_div_no_branch will be called eventually. | |
496 | */ | |
fd7d2520 MC |
497 | { |
498 | BIGNUM local_B; | |
d59c7c81 | 499 | bn_init(&local_B); |
fd7d2520 MC |
500 | BN_with_flags(&local_B, B, BN_FLG_CONSTTIME); |
501 | if (!BN_nnmod(B, &local_B, A, ctx)) | |
502 | goto err; | |
503 | /* Ensure local_B goes out of scope before any further use of B */ | |
504 | } | |
0f113f3e MC |
505 | } |
506 | sign = -1; | |
50e735f9 MC |
507 | /*- |
508 | * From B = a mod |n|, A = |n| it follows that | |
509 | * | |
510 | * 0 <= B < A, | |
511 | * -sign*X*a == B (mod |n|), | |
512 | * sign*Y*a == A (mod |n|). | |
513 | */ | |
0f113f3e MC |
514 | |
515 | while (!BN_is_zero(B)) { | |
516 | BIGNUM *tmp; | |
517 | ||
50e735f9 MC |
518 | /*- |
519 | * 0 < B < A, | |
520 | * (*) -sign*X*a == B (mod |n|), | |
521 | * sign*Y*a == A (mod |n|) | |
522 | */ | |
0f113f3e MC |
523 | |
524 | /* | |
525 | * Turn BN_FLG_CONSTTIME flag on, so that when BN_div is invoked, | |
526 | * BN_div_no_branch will be called eventually. | |
527 | */ | |
fd7d2520 MC |
528 | { |
529 | BIGNUM local_A; | |
d59c7c81 | 530 | bn_init(&local_A); |
fd7d2520 | 531 | BN_with_flags(&local_A, A, BN_FLG_CONSTTIME); |
0f113f3e | 532 | |
fd7d2520 MC |
533 | /* (D, M) := (A/B, A%B) ... */ |
534 | if (!BN_div(D, M, &local_A, B, ctx)) | |
535 | goto err; | |
536 | /* Ensure local_A goes out of scope before any further use of A */ | |
537 | } | |
0f113f3e | 538 | |
50e735f9 MC |
539 | /*- |
540 | * Now | |
541 | * A = D*B + M; | |
542 | * thus we have | |
543 | * (**) sign*Y*a == D*B + M (mod |n|). | |
544 | */ | |
0f113f3e MC |
545 | |
546 | tmp = A; /* keep the BIGNUM object, the value does not | |
547 | * matter */ | |
548 | ||
549 | /* (A, B) := (B, A mod B) ... */ | |
550 | A = B; | |
551 | B = M; | |
552 | /* ... so we have 0 <= B < A again */ | |
553 | ||
50e735f9 MC |
554 | /*- |
555 | * Since the former M is now B and the former B is now A, | |
556 | * (**) translates into | |
557 | * sign*Y*a == D*A + B (mod |n|), | |
558 | * i.e. | |
559 | * sign*Y*a - D*A == B (mod |n|). | |
560 | * Similarly, (*) translates into | |
561 | * -sign*X*a == A (mod |n|). | |
562 | * | |
563 | * Thus, | |
564 | * sign*Y*a + D*sign*X*a == B (mod |n|), | |
565 | * i.e. | |
566 | * sign*(Y + D*X)*a == B (mod |n|). | |
567 | * | |
568 | * So if we set (X, Y, sign) := (Y + D*X, X, -sign), we arrive back at | |
569 | * -sign*X*a == B (mod |n|), | |
570 | * sign*Y*a == A (mod |n|). | |
571 | * Note that X and Y stay non-negative all the time. | |
572 | */ | |
0f113f3e MC |
573 | |
574 | if (!BN_mul(tmp, D, X, ctx)) | |
575 | goto err; | |
576 | if (!BN_add(tmp, tmp, Y)) | |
577 | goto err; | |
578 | ||
579 | M = Y; /* keep the BIGNUM object, the value does not | |
580 | * matter */ | |
581 | Y = X; | |
582 | X = tmp; | |
583 | sign = -sign; | |
584 | } | |
585 | ||
50e735f9 MC |
586 | /*- |
587 | * The while loop (Euclid's algorithm) ends when | |
588 | * A == gcd(a,n); | |
589 | * we have | |
590 | * sign*Y*a == A (mod |n|), | |
591 | * where Y is non-negative. | |
592 | */ | |
0f113f3e MC |
593 | |
594 | if (sign < 0) { | |
595 | if (!BN_sub(Y, n, Y)) | |
596 | goto err; | |
597 | } | |
598 | /* Now Y*a == A (mod |n|). */ | |
599 | ||
600 | if (BN_is_one(A)) { | |
601 | /* Y*a == 1 (mod |n|) */ | |
602 | if (!Y->neg && BN_ucmp(Y, n) < 0) { | |
603 | if (!BN_copy(R, Y)) | |
604 | goto err; | |
605 | } else { | |
606 | if (!BN_nnmod(R, Y, n, ctx)) | |
607 | goto err; | |
608 | } | |
609 | } else { | |
610 | BNerr(BN_F_BN_MOD_INVERSE_NO_BRANCH, BN_R_NO_INVERSE); | |
611 | goto err; | |
612 | } | |
613 | ret = R; | |
614 | err: | |
615 | if ((ret == NULL) && (in == NULL)) | |
616 | BN_free(R); | |
617 | BN_CTX_end(ctx); | |
618 | bn_check_top(ret); | |
619 | return (ret); | |
620 | } |