eng_rsax.c 20 KB

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  1. /* crypto/engine/eng_rsax.c */
  2. /* Copyright (c) 2010-2010 Intel Corp.
  3. * Author: [email protected]
  4. * Jim Guilford
  5. * [email protected]
  6. * [email protected]
  7. * [email protected]
  8. *
  9. * More information about algorithm used can be found at:
  10. * http://www.cse.buffalo.edu/srds2009/escs2009_submission_Gopal.pdf
  11. */
  12. /* ====================================================================
  13. * Copyright (c) 1999-2001 The OpenSSL Project. All rights reserved.
  14. *
  15. * Redistribution and use in source and binary forms, with or without
  16. * modification, are permitted provided that the following conditions
  17. * are met:
  18. *
  19. * 1. Redistributions of source code must retain the above copyright
  20. * notice, this list of conditions and the following disclaimer.
  21. *
  22. * 2. Redistributions in binary form must reproduce the above copyright
  23. * notice, this list of conditions and the following disclaimer in
  24. * the documentation and/or other materials provided with the
  25. * distribution.
  26. *
  27. * 3. All advertising materials mentioning features or use of this
  28. * software must display the following acknowledgment:
  29. * "This product includes software developed by the OpenSSL Project
  30. * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  31. *
  32. * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  33. * endorse or promote products derived from this software without
  34. * prior written permission. For written permission, please contact
  35. * [email protected].
  36. *
  37. * 5. Products derived from this software may not be called "OpenSSL"
  38. * nor may "OpenSSL" appear in their names without prior written
  39. * permission of the OpenSSL Project.
  40. *
  41. * 6. Redistributions of any form whatsoever must retain the following
  42. * acknowledgment:
  43. * "This product includes software developed by the OpenSSL Project
  44. * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  45. *
  46. * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  47. * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  49. * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
  50. * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  51. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  52. * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  53. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  55. * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  56. * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  57. * OF THE POSSIBILITY OF SUCH DAMAGE.
  58. * ====================================================================
  59. *
  60. * This product includes cryptographic software written by Eric Young
  61. * ([email protected]). This product includes software written by Tim
  62. * Hudson ([email protected]).
  63. */
  64. #include <openssl/opensslconf.h>
  65. #include <stdio.h>
  66. #include <string.h>
  67. #include <openssl/crypto.h>
  68. #include <openssl/buffer.h>
  69. #include <openssl/engine.h>
  70. #ifndef OPENSSL_NO_RSA
  71. # include <openssl/rsa.h>
  72. #endif
  73. #include <openssl/bn.h>
  74. #include <openssl/err.h>
  75. /* RSAX is available **ONLY* on x86_64 CPUs */
  76. #undef COMPILE_RSAX
  77. #if (defined(__x86_64) || defined(__x86_64__) || \
  78. defined(_M_AMD64) || defined (_M_X64)) && !defined(OPENSSL_NO_ASM)
  79. # define COMPILE_RSAX
  80. static ENGINE *ENGINE_rsax(void);
  81. #endif
  82. void ENGINE_load_rsax(void)
  83. {
  84. /* On non-x86 CPUs it just returns. */
  85. #ifdef COMPILE_RSAX
  86. ENGINE *toadd = ENGINE_rsax();
  87. if (!toadd)
  88. return;
  89. ENGINE_add(toadd);
  90. ENGINE_free(toadd);
  91. ERR_clear_error();
  92. #endif
  93. }
  94. #ifdef COMPILE_RSAX
  95. # define E_RSAX_LIB_NAME "rsax engine"
  96. static int e_rsax_destroy(ENGINE *e);
  97. static int e_rsax_init(ENGINE *e);
  98. static int e_rsax_finish(ENGINE *e);
  99. static int e_rsax_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void));
  100. # ifndef OPENSSL_NO_RSA
  101. /* RSA stuff */
  102. static int e_rsax_rsa_mod_exp(BIGNUM *r, const BIGNUM *I, RSA *rsa,
  103. BN_CTX *ctx);
  104. static int e_rsax_rsa_finish(RSA *r);
  105. # endif
  106. static const ENGINE_CMD_DEFN e_rsax_cmd_defns[] = {
  107. {0, NULL, NULL, 0}
  108. };
  109. # ifndef OPENSSL_NO_RSA
  110. /* Our internal RSA_METHOD that we provide pointers to */
  111. static RSA_METHOD e_rsax_rsa = {
  112. "Intel RSA-X method",
  113. NULL,
  114. NULL,
  115. NULL,
  116. NULL,
  117. e_rsax_rsa_mod_exp,
  118. NULL,
  119. NULL,
  120. e_rsax_rsa_finish,
  121. RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE,
  122. NULL,
  123. NULL,
  124. NULL
  125. };
  126. # endif
  127. /* Constants used when creating the ENGINE */
  128. static const char *engine_e_rsax_id = "rsax";
  129. static const char *engine_e_rsax_name = "RSAX engine support";
  130. /* This internal function is used by ENGINE_rsax() */
  131. static int bind_helper(ENGINE *e)
  132. {
  133. # ifndef OPENSSL_NO_RSA
  134. const RSA_METHOD *meth1;
  135. # endif
  136. if (!ENGINE_set_id(e, engine_e_rsax_id) ||
  137. !ENGINE_set_name(e, engine_e_rsax_name) ||
  138. # ifndef OPENSSL_NO_RSA
  139. !ENGINE_set_RSA(e, &e_rsax_rsa) ||
  140. # endif
  141. !ENGINE_set_destroy_function(e, e_rsax_destroy) ||
  142. !ENGINE_set_init_function(e, e_rsax_init) ||
  143. !ENGINE_set_finish_function(e, e_rsax_finish) ||
  144. !ENGINE_set_ctrl_function(e, e_rsax_ctrl) ||
  145. !ENGINE_set_cmd_defns(e, e_rsax_cmd_defns))
  146. return 0;
  147. # ifndef OPENSSL_NO_RSA
  148. meth1 = RSA_PKCS1_SSLeay();
  149. e_rsax_rsa.rsa_pub_enc = meth1->rsa_pub_enc;
  150. e_rsax_rsa.rsa_pub_dec = meth1->rsa_pub_dec;
  151. e_rsax_rsa.rsa_priv_enc = meth1->rsa_priv_enc;
  152. e_rsax_rsa.rsa_priv_dec = meth1->rsa_priv_dec;
  153. e_rsax_rsa.bn_mod_exp = meth1->bn_mod_exp;
  154. # endif
  155. return 1;
  156. }
  157. static ENGINE *ENGINE_rsax(void)
  158. {
  159. ENGINE *ret = ENGINE_new();
  160. if (!ret)
  161. return NULL;
  162. if (!bind_helper(ret)) {
  163. ENGINE_free(ret);
  164. return NULL;
  165. }
  166. return ret;
  167. }
  168. # ifndef OPENSSL_NO_RSA
  169. /* Used to attach our own key-data to an RSA structure */
  170. static int rsax_ex_data_idx = -1;
  171. # endif
  172. static int e_rsax_destroy(ENGINE *e)
  173. {
  174. return 1;
  175. }
  176. /* (de)initialisation functions. */
  177. static int e_rsax_init(ENGINE *e)
  178. {
  179. # ifndef OPENSSL_NO_RSA
  180. if (rsax_ex_data_idx == -1)
  181. rsax_ex_data_idx = RSA_get_ex_new_index(0, NULL, NULL, NULL, NULL);
  182. # endif
  183. if (rsax_ex_data_idx == -1)
  184. return 0;
  185. return 1;
  186. }
  187. static int e_rsax_finish(ENGINE *e)
  188. {
  189. return 1;
  190. }
  191. static int e_rsax_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
  192. {
  193. int to_return = 1;
  194. switch (cmd) {
  195. /* The command isn't understood by this engine */
  196. default:
  197. to_return = 0;
  198. break;
  199. }
  200. return to_return;
  201. }
  202. # ifndef OPENSSL_NO_RSA
  203. # ifdef _WIN32
  204. typedef unsigned __int64 UINT64;
  205. # else
  206. typedef unsigned long long UINT64;
  207. # endif
  208. typedef unsigned short UINT16;
  209. /*
  210. * Table t is interleaved in the following manner: The order in memory is
  211. * t[0][0], t[0][1], ..., t[0][7], t[1][0], ... A particular 512-bit value is
  212. * stored in t[][index] rather than the more normal t[index][]; i.e. the
  213. * qwords of a particular entry in t are not adjacent in memory
  214. */
  215. /* Init BIGNUM b from the interleaved UINT64 array */
  216. static int interleaved_array_to_bn_512(BIGNUM *b, UINT64 *array);
  217. /*
  218. * Extract array elements from BIGNUM b To set the whole array from b, call
  219. * with n=8
  220. */
  221. static int bn_extract_to_array_512(const BIGNUM *b, unsigned int n,
  222. UINT64 *array);
  223. struct mod_ctx_512 {
  224. UINT64 t[8][8];
  225. UINT64 m[8];
  226. UINT64 m1[8]; /* 2^278 % m */
  227. UINT64 m2[8]; /* 2^640 % m */
  228. UINT64 k1[2]; /* (- 1/m) % 2^128 */
  229. };
  230. static int mod_exp_pre_compute_data_512(UINT64 *m, struct mod_ctx_512 *data);
  231. void mod_exp_512(UINT64 *result, /* 512 bits, 8 qwords */
  232. UINT64 *g, /* 512 bits, 8 qwords */
  233. UINT64 *exp, /* 512 bits, 8 qwords */
  234. struct mod_ctx_512 *data);
  235. typedef struct st_e_rsax_mod_ctx {
  236. UINT64 type;
  237. union {
  238. struct mod_ctx_512 b512;
  239. } ctx;
  240. } E_RSAX_MOD_CTX;
  241. static E_RSAX_MOD_CTX *e_rsax_get_ctx(RSA *rsa, int idx, BIGNUM *m)
  242. {
  243. E_RSAX_MOD_CTX *hptr;
  244. if (idx < 0 || idx > 2)
  245. return NULL;
  246. hptr = RSA_get_ex_data(rsa, rsax_ex_data_idx);
  247. if (!hptr) {
  248. hptr = OPENSSL_malloc(3 * sizeof(E_RSAX_MOD_CTX));
  249. if (!hptr)
  250. return NULL;
  251. hptr[2].type = hptr[1].type = hptr[0].type = 0;
  252. RSA_set_ex_data(rsa, rsax_ex_data_idx, hptr);
  253. }
  254. if (hptr[idx].type == (UINT64)BN_num_bits(m))
  255. return hptr + idx;
  256. if (BN_num_bits(m) == 512) {
  257. UINT64 _m[8];
  258. bn_extract_to_array_512(m, 8, _m);
  259. memset(&hptr[idx].ctx.b512, 0, sizeof(struct mod_ctx_512));
  260. mod_exp_pre_compute_data_512(_m, &hptr[idx].ctx.b512);
  261. }
  262. hptr[idx].type = BN_num_bits(m);
  263. return hptr + idx;
  264. }
  265. static int e_rsax_rsa_finish(RSA *rsa)
  266. {
  267. E_RSAX_MOD_CTX *hptr = RSA_get_ex_data(rsa, rsax_ex_data_idx);
  268. if (hptr) {
  269. OPENSSL_free(hptr);
  270. RSA_set_ex_data(rsa, rsax_ex_data_idx, NULL);
  271. }
  272. if (rsa->_method_mod_n)
  273. BN_MONT_CTX_free(rsa->_method_mod_n);
  274. if (rsa->_method_mod_p)
  275. BN_MONT_CTX_free(rsa->_method_mod_p);
  276. if (rsa->_method_mod_q)
  277. BN_MONT_CTX_free(rsa->_method_mod_q);
  278. return 1;
  279. }
  280. static int e_rsax_bn_mod_exp(BIGNUM *r, const BIGNUM *g, const BIGNUM *e,
  281. const BIGNUM *m, BN_CTX *ctx,
  282. BN_MONT_CTX *in_mont,
  283. E_RSAX_MOD_CTX *rsax_mod_ctx)
  284. {
  285. if (rsax_mod_ctx && BN_get_flags(e, BN_FLG_CONSTTIME) != 0) {
  286. if (BN_num_bits(m) == 512) {
  287. UINT64 _r[8];
  288. UINT64 _g[8];
  289. UINT64 _e[8];
  290. /* Init the arrays from the BIGNUMs */
  291. bn_extract_to_array_512(g, 8, _g);
  292. bn_extract_to_array_512(e, 8, _e);
  293. mod_exp_512(_r, _g, _e, &rsax_mod_ctx->ctx.b512);
  294. /* Return the result in the BIGNUM */
  295. interleaved_array_to_bn_512(r, _r);
  296. return 1;
  297. }
  298. }
  299. return BN_mod_exp_mont(r, g, e, m, ctx, in_mont);
  300. }
  301. /*
  302. * Declares for the Intel CIAP 512-bit / CRT / 1024 bit RSA modular
  303. * exponentiation routine precalculations and a structure to hold the
  304. * necessary values. These files are meant to live in crypto/rsa/ in the
  305. * target openssl.
  306. */
  307. /*
  308. * Local method: extracts a piece from a BIGNUM, to fit it into
  309. * an array. Call with n=8 to extract an entire 512-bit BIGNUM
  310. */
  311. static int bn_extract_to_array_512(const BIGNUM *b, unsigned int n,
  312. UINT64 *array)
  313. {
  314. int i;
  315. UINT64 tmp;
  316. unsigned char bn_buff[64];
  317. memset(bn_buff, 0, 64);
  318. if (BN_num_bytes(b) > 64) {
  319. printf("Can't support this byte size\n");
  320. return 0;
  321. }
  322. if (BN_num_bytes(b) != 0) {
  323. if (!BN_bn2bin(b, bn_buff + (64 - BN_num_bytes(b)))) {
  324. printf("Error's in bn2bin\n");
  325. /* We have to error, here */
  326. return 0;
  327. }
  328. }
  329. while (n-- > 0) {
  330. array[n] = 0;
  331. for (i = 7; i >= 0; i--) {
  332. tmp = bn_buff[63 - (n * 8 + i)];
  333. array[n] |= tmp << (8 * i);
  334. }
  335. }
  336. return 1;
  337. }
  338. /* Init a 512-bit BIGNUM from the UINT64*_ (8 * 64) interleaved array */
  339. static int interleaved_array_to_bn_512(BIGNUM *b, UINT64 *array)
  340. {
  341. unsigned char tmp[64];
  342. int n = 8;
  343. int i;
  344. while (n-- > 0) {
  345. for (i = 7; i >= 0; i--) {
  346. tmp[63 - (n * 8 + i)] = (unsigned char)(array[n] >> (8 * i));
  347. }}
  348. BN_bin2bn(tmp, 64, b);
  349. return 0;
  350. }
  351. /* The main 512bit precompute call */
  352. static int mod_exp_pre_compute_data_512(UINT64 *m, struct mod_ctx_512 *data)
  353. {
  354. BIGNUM two_768, two_640, two_128, two_512, tmp, _m, tmp2;
  355. /* We need a BN_CTX for the modulo functions */
  356. BN_CTX *ctx;
  357. /* Some tmps */
  358. UINT64 _t[8];
  359. int i, j, ret = 0;
  360. /* Init _m with m */
  361. BN_init(&_m);
  362. interleaved_array_to_bn_512(&_m, m);
  363. memset(_t, 0, 64);
  364. /* Inits */
  365. BN_init(&two_768);
  366. BN_init(&two_640);
  367. BN_init(&two_128);
  368. BN_init(&two_512);
  369. BN_init(&tmp);
  370. BN_init(&tmp2);
  371. /* Create our context */
  372. if ((ctx = BN_CTX_new()) == NULL) {
  373. goto err;
  374. }
  375. BN_CTX_start(ctx);
  376. /*
  377. * For production, if you care, these only need to be set once,
  378. * and may be made constants.
  379. */
  380. BN_lshift(&two_768, BN_value_one(), 768);
  381. BN_lshift(&two_640, BN_value_one(), 640);
  382. BN_lshift(&two_128, BN_value_one(), 128);
  383. BN_lshift(&two_512, BN_value_one(), 512);
  384. if (0 == (m[7] & 0x8000000000000000)) {
  385. goto err;
  386. }
  387. if (0 == (m[0] & 0x1)) { /* Odd modulus required for Mont */
  388. goto err;
  389. }
  390. /* Precompute m1 */
  391. BN_mod(&tmp, &two_768, &_m, ctx);
  392. if (!bn_extract_to_array_512(&tmp, 8, &data->m1[0])) {
  393. goto err;
  394. }
  395. /* Precompute m2 */
  396. BN_mod(&tmp, &two_640, &_m, ctx);
  397. if (!bn_extract_to_array_512(&tmp, 8, &data->m2[0])) {
  398. goto err;
  399. }
  400. /*
  401. * Precompute k1, a 128b number = ((-1)* m-1 ) mod 2128; k1 should
  402. * be non-negative.
  403. */
  404. BN_mod_inverse(&tmp, &_m, &two_128, ctx);
  405. if (!BN_is_zero(&tmp)) {
  406. BN_sub(&tmp, &two_128, &tmp);
  407. }
  408. if (!bn_extract_to_array_512(&tmp, 2, &data->k1[0])) {
  409. goto err;
  410. }
  411. /* Precompute t */
  412. for (i = 0; i < 8; i++) {
  413. BN_zero(&tmp);
  414. if (i & 1) {
  415. BN_add(&tmp, &two_512, &tmp);
  416. }
  417. if (i & 2) {
  418. BN_add(&tmp, &two_512, &tmp);
  419. }
  420. if (i & 4) {
  421. BN_add(&tmp, &two_640, &tmp);
  422. }
  423. BN_nnmod(&tmp2, &tmp, &_m, ctx);
  424. if (!bn_extract_to_array_512(&tmp2, 8, _t)) {
  425. goto err;
  426. }
  427. for (j = 0; j < 8; j++)
  428. data->t[j][i] = _t[j];
  429. }
  430. /* Precompute m */
  431. for (i = 0; i < 8; i++) {
  432. data->m[i] = m[i];
  433. }
  434. ret = 1;
  435. err:
  436. /* Cleanup */
  437. if (ctx != NULL) {
  438. BN_CTX_end(ctx);
  439. BN_CTX_free(ctx);
  440. }
  441. BN_free(&two_768);
  442. BN_free(&two_640);
  443. BN_free(&two_128);
  444. BN_free(&two_512);
  445. BN_free(&tmp);
  446. BN_free(&tmp2);
  447. BN_free(&_m);
  448. return ret;
  449. }
  450. static int e_rsax_rsa_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa,
  451. BN_CTX *ctx)
  452. {
  453. BIGNUM *r1, *m1, *vrfy;
  454. BIGNUM local_dmp1, local_dmq1, local_c, local_r1;
  455. BIGNUM *dmp1, *dmq1, *c, *pr1;
  456. int ret = 0;
  457. BN_CTX_start(ctx);
  458. r1 = BN_CTX_get(ctx);
  459. m1 = BN_CTX_get(ctx);
  460. vrfy = BN_CTX_get(ctx);
  461. {
  462. BIGNUM local_p, local_q;
  463. BIGNUM *p = NULL, *q = NULL;
  464. int error = 0;
  465. /*
  466. * Make sure BN_mod_inverse in Montgomery intialization uses the
  467. * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
  468. */
  469. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  470. BN_init(&local_p);
  471. p = &local_p;
  472. BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
  473. BN_init(&local_q);
  474. q = &local_q;
  475. BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
  476. } else {
  477. p = rsa->p;
  478. q = rsa->q;
  479. }
  480. if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
  481. if (!BN_MONT_CTX_set_locked
  482. (&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx))
  483. error = 1;
  484. if (!BN_MONT_CTX_set_locked
  485. (&rsa->_method_mod_q, CRYPTO_LOCK_RSA, q, ctx))
  486. error = 1;
  487. }
  488. /* clean up */
  489. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  490. BN_free(&local_p);
  491. BN_free(&local_q);
  492. }
  493. if (error)
  494. goto err;
  495. }
  496. if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
  497. if (!BN_MONT_CTX_set_locked
  498. (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
  499. goto err;
  500. /* compute I mod q */
  501. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  502. c = &local_c;
  503. BN_with_flags(c, I, BN_FLG_CONSTTIME);
  504. if (!BN_mod(r1, c, rsa->q, ctx))
  505. goto err;
  506. } else {
  507. if (!BN_mod(r1, I, rsa->q, ctx))
  508. goto err;
  509. }
  510. /* compute r1^dmq1 mod q */
  511. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  512. dmq1 = &local_dmq1;
  513. BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
  514. } else
  515. dmq1 = rsa->dmq1;
  516. if (!e_rsax_bn_mod_exp(m1, r1, dmq1, rsa->q, ctx,
  517. rsa->_method_mod_q, e_rsax_get_ctx(rsa, 0,
  518. rsa->q)))
  519. goto err;
  520. /* compute I mod p */
  521. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  522. c = &local_c;
  523. BN_with_flags(c, I, BN_FLG_CONSTTIME);
  524. if (!BN_mod(r1, c, rsa->p, ctx))
  525. goto err;
  526. } else {
  527. if (!BN_mod(r1, I, rsa->p, ctx))
  528. goto err;
  529. }
  530. /* compute r1^dmp1 mod p */
  531. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  532. dmp1 = &local_dmp1;
  533. BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
  534. } else
  535. dmp1 = rsa->dmp1;
  536. if (!e_rsax_bn_mod_exp(r0, r1, dmp1, rsa->p, ctx,
  537. rsa->_method_mod_p, e_rsax_get_ctx(rsa, 1,
  538. rsa->p)))
  539. goto err;
  540. if (!BN_sub(r0, r0, m1))
  541. goto err;
  542. /*
  543. * This will help stop the size of r0 increasing, which does affect the
  544. * multiply if it optimised for a power of 2 size
  545. */
  546. if (BN_is_negative(r0))
  547. if (!BN_add(r0, r0, rsa->p))
  548. goto err;
  549. if (!BN_mul(r1, r0, rsa->iqmp, ctx))
  550. goto err;
  551. /* Turn BN_FLG_CONSTTIME flag on before division operation */
  552. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  553. pr1 = &local_r1;
  554. BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
  555. } else
  556. pr1 = r1;
  557. if (!BN_mod(r0, pr1, rsa->p, ctx))
  558. goto err;
  559. /*
  560. * If p < q it is occasionally possible for the correction of adding 'p'
  561. * if r0 is negative above to leave the result still negative. This can
  562. * break the private key operations: the following second correction
  563. * should *always* correct this rare occurrence. This will *never* happen
  564. * with OpenSSL generated keys because they ensure p > q [steve]
  565. */
  566. if (BN_is_negative(r0))
  567. if (!BN_add(r0, r0, rsa->p))
  568. goto err;
  569. if (!BN_mul(r1, r0, rsa->q, ctx))
  570. goto err;
  571. if (!BN_add(r0, r1, m1))
  572. goto err;
  573. if (rsa->e && rsa->n) {
  574. if (!e_rsax_bn_mod_exp
  575. (vrfy, r0, rsa->e, rsa->n, ctx, rsa->_method_mod_n,
  576. e_rsax_get_ctx(rsa, 2, rsa->n)))
  577. goto err;
  578. /*
  579. * If 'I' was greater than (or equal to) rsa->n, the operation will
  580. * be equivalent to using 'I mod n'. However, the result of the
  581. * verify will *always* be less than 'n' so we don't check for
  582. * absolute equality, just congruency.
  583. */
  584. if (!BN_sub(vrfy, vrfy, I))
  585. goto err;
  586. if (!BN_mod(vrfy, vrfy, rsa->n, ctx))
  587. goto err;
  588. if (BN_is_negative(vrfy))
  589. if (!BN_add(vrfy, vrfy, rsa->n))
  590. goto err;
  591. if (!BN_is_zero(vrfy)) {
  592. /*
  593. * 'I' and 'vrfy' aren't congruent mod n. Don't leak
  594. * miscalculated CRT output, just do a raw (slower) mod_exp and
  595. * return that instead.
  596. */
  597. BIGNUM local_d;
  598. BIGNUM *d = NULL;
  599. if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
  600. d = &local_d;
  601. BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
  602. } else
  603. d = rsa->d;
  604. if (!e_rsax_bn_mod_exp(r0, I, d, rsa->n, ctx,
  605. rsa->_method_mod_n, e_rsax_get_ctx(rsa, 2,
  606. rsa->n)))
  607. goto err;
  608. }
  609. }
  610. ret = 1;
  611. err:
  612. BN_CTX_end(ctx);
  613. return ret;
  614. }
  615. # endif /* !OPENSSL_NO_RSA */
  616. #endif /* !COMPILE_RSAX */