1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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 #include <openssl/rsa.h> 58 59 #include <string.h> 60 61 #include <openssl/bn.h> 62 #include <openssl/engine.h> 63 #include <openssl/err.h> 64 #include <openssl/ex_data.h> 65 #include <openssl/mem.h> 66 #include <openssl/obj.h> 67 #include <openssl/thread.h> 68 69 #include "internal.h" 70 #include "../internal.h" 71 72 73 extern const RSA_METHOD RSA_default_method; 74 75 static CRYPTO_EX_DATA_CLASS g_ex_data_class = CRYPTO_EX_DATA_CLASS_INIT; 76 77 RSA *RSA_new(void) { return RSA_new_method(NULL); } 78 79 RSA *RSA_new_method(const ENGINE *engine) { 80 RSA *rsa = (RSA *)OPENSSL_malloc(sizeof(RSA)); 81 if (rsa == NULL) { 82 OPENSSL_PUT_ERROR(RSA, RSA_new_method, ERR_R_MALLOC_FAILURE); 83 return NULL; 84 } 85 86 memset(rsa, 0, sizeof(RSA)); 87 88 if (engine) { 89 rsa->meth = ENGINE_get_RSA_method(engine); 90 } 91 92 if (rsa->meth == NULL) { 93 rsa->meth = (RSA_METHOD*) &RSA_default_method; 94 } 95 METHOD_ref(rsa->meth); 96 97 rsa->references = 1; 98 rsa->flags = rsa->meth->flags; 99 CRYPTO_MUTEX_init(&rsa->lock); 100 101 if (!CRYPTO_new_ex_data(&g_ex_data_class, rsa, &rsa->ex_data)) { 102 METHOD_unref(rsa->meth); 103 OPENSSL_free(rsa); 104 return NULL; 105 } 106 107 if (rsa->meth->init && !rsa->meth->init(rsa)) { 108 CRYPTO_free_ex_data(&g_ex_data_class, rsa, &rsa->ex_data); 109 METHOD_unref(rsa->meth); 110 OPENSSL_free(rsa); 111 return NULL; 112 } 113 114 return rsa; 115 } 116 117 void RSA_free(RSA *rsa) { 118 unsigned u; 119 120 if (rsa == NULL) { 121 return; 122 } 123 124 if (!CRYPTO_refcount_dec_and_test_zero(&rsa->references)) { 125 return; 126 } 127 128 if (rsa->meth->finish) { 129 rsa->meth->finish(rsa); 130 } 131 METHOD_unref(rsa->meth); 132 133 CRYPTO_free_ex_data(&g_ex_data_class, rsa, &rsa->ex_data); 134 135 BN_clear_free(rsa->n); 136 BN_clear_free(rsa->e); 137 BN_clear_free(rsa->d); 138 BN_clear_free(rsa->p); 139 BN_clear_free(rsa->q); 140 BN_clear_free(rsa->dmp1); 141 BN_clear_free(rsa->dmq1); 142 BN_clear_free(rsa->iqmp); 143 for (u = 0; u < rsa->num_blindings; u++) { 144 BN_BLINDING_free(rsa->blindings[u]); 145 } 146 OPENSSL_free(rsa->blindings); 147 OPENSSL_free(rsa->blindings_inuse); 148 CRYPTO_MUTEX_cleanup(&rsa->lock); 149 OPENSSL_free(rsa); 150 } 151 152 int RSA_up_ref(RSA *rsa) { 153 CRYPTO_refcount_inc(&rsa->references); 154 return 1; 155 } 156 157 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) { 158 if (rsa->meth->keygen) { 159 return rsa->meth->keygen(rsa, bits, e_value, cb); 160 } 161 162 return RSA_default_method.keygen(rsa, bits, e_value, cb); 163 } 164 165 int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, 166 const uint8_t *in, size_t in_len, int padding) { 167 if (rsa->meth->encrypt) { 168 return rsa->meth->encrypt(rsa, out_len, out, max_out, in, in_len, padding); 169 } 170 171 return RSA_default_method.encrypt(rsa, out_len, out, max_out, in, in_len, 172 padding); 173 } 174 175 int RSA_public_encrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, 176 int padding) { 177 size_t out_len; 178 179 if (!RSA_encrypt(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { 180 return -1; 181 } 182 183 return out_len; 184 } 185 186 int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, 187 const uint8_t *in, size_t in_len, int padding) { 188 if (rsa->meth->sign_raw) { 189 return rsa->meth->sign_raw(rsa, out_len, out, max_out, in, in_len, padding); 190 } 191 192 return RSA_default_method.sign_raw(rsa, out_len, out, max_out, in, in_len, 193 padding); 194 } 195 196 int RSA_private_encrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, 197 int padding) { 198 size_t out_len; 199 200 if (!RSA_sign_raw(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { 201 return -1; 202 } 203 204 return out_len; 205 } 206 207 int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, 208 const uint8_t *in, size_t in_len, int padding) { 209 if (rsa->meth->decrypt) { 210 return rsa->meth->decrypt(rsa, out_len, out, max_out, in, in_len, padding); 211 } 212 213 return RSA_default_method.decrypt(rsa, out_len, out, max_out, in, in_len, 214 padding); 215 } 216 217 int RSA_private_decrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, 218 int padding) { 219 size_t out_len; 220 221 if (!RSA_decrypt(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { 222 return -1; 223 } 224 225 return out_len; 226 } 227 228 int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, 229 const uint8_t *in, size_t in_len, int padding) { 230 if (rsa->meth->verify_raw) { 231 return rsa->meth->verify_raw(rsa, out_len, out, max_out, in, in_len, padding); 232 } 233 234 return RSA_default_method.verify_raw(rsa, out_len, out, max_out, in, in_len, 235 padding); 236 } 237 238 int RSA_public_decrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, 239 int padding) { 240 size_t out_len; 241 242 if (!RSA_verify_raw(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { 243 return -1; 244 } 245 246 return out_len; 247 } 248 249 unsigned RSA_size(const RSA *rsa) { 250 if (rsa->meth->size) { 251 return rsa->meth->size(rsa); 252 } 253 254 return RSA_default_method.size(rsa); 255 } 256 257 int RSA_is_opaque(const RSA *rsa) { 258 return rsa->meth && (rsa->meth->flags & RSA_FLAG_OPAQUE); 259 } 260 261 int RSA_supports_digest(const RSA *rsa, const EVP_MD *md) { 262 if (rsa->meth && rsa->meth->supports_digest) { 263 return rsa->meth->supports_digest(rsa, md); 264 } 265 return 1; 266 } 267 268 int RSA_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func, 269 CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func) { 270 int index; 271 if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp, new_func, 272 dup_func, free_func)) { 273 return -1; 274 } 275 return index; 276 } 277 278 int RSA_set_ex_data(RSA *d, int idx, void *arg) { 279 return CRYPTO_set_ex_data(&d->ex_data, idx, arg); 280 } 281 282 void *RSA_get_ex_data(const RSA *d, int idx) { 283 return CRYPTO_get_ex_data(&d->ex_data, idx); 284 } 285 286 /* SSL_SIG_LENGTH is the size of an SSL/TLS (prior to TLS 1.2) signature: it's 287 * the length of an MD5 and SHA1 hash. */ 288 static const unsigned SSL_SIG_LENGTH = 36; 289 290 /* pkcs1_sig_prefix contains the ASN.1, DER encoded prefix for a hash that is 291 * to be signed with PKCS#1. */ 292 struct pkcs1_sig_prefix { 293 /* nid identifies the hash function. */ 294 int nid; 295 /* len is the number of bytes of |bytes| which are valid. */ 296 uint8_t len; 297 /* bytes contains the DER bytes. */ 298 uint8_t bytes[19]; 299 }; 300 301 /* kPKCS1SigPrefixes contains the ASN.1 prefixes for PKCS#1 signatures with 302 * different hash functions. */ 303 static const struct pkcs1_sig_prefix kPKCS1SigPrefixes[] = { 304 { 305 NID_md5, 306 18, 307 {0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 308 0x02, 0x05, 0x05, 0x00, 0x04, 0x10}, 309 }, 310 { 311 NID_sha1, 312 15, 313 {0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a, 0x05, 314 0x00, 0x04, 0x14}, 315 }, 316 { 317 NID_sha224, 318 19, 319 {0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 320 0x04, 0x02, 0x04, 0x05, 0x00, 0x04, 0x1c}, 321 }, 322 { 323 NID_sha256, 324 19, 325 {0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 326 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20}, 327 }, 328 { 329 NID_sha384, 330 19, 331 {0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 332 0x04, 0x02, 0x02, 0x05, 0x00, 0x04, 0x30}, 333 }, 334 { 335 NID_sha512, 336 19, 337 {0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 338 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40}, 339 }, 340 { 341 NID_undef, 0, {0}, 342 }, 343 }; 344 345 /* TODO(fork): mostly new code, needs careful review. */ 346 347 /* pkcs1_prefixed_msg builds a PKCS#1, prefixed version of |msg| for the given 348 * hash function and sets |out_msg| to point to it. On successful return, 349 * |*out_msg| may be allocated memory and, if so, |*is_alloced| will be 1. */ 350 static int pkcs1_prefixed_msg(uint8_t **out_msg, size_t *out_msg_len, 351 int *is_alloced, int hash_nid, const uint8_t *msg, 352 size_t msg_len) { 353 unsigned i; 354 355 if (hash_nid == NID_md5_sha1) { 356 /* Special case: SSL signature, just check the length. */ 357 if (msg_len != SSL_SIG_LENGTH) { 358 OPENSSL_PUT_ERROR(RSA, pkcs1_prefixed_msg, RSA_R_INVALID_MESSAGE_LENGTH); 359 return 0; 360 } 361 362 *out_msg = (uint8_t*) msg; 363 *out_msg_len = SSL_SIG_LENGTH; 364 *is_alloced = 0; 365 return 1; 366 } 367 368 for (i = 0; kPKCS1SigPrefixes[i].nid != NID_undef; i++) { 369 const struct pkcs1_sig_prefix *sig_prefix = &kPKCS1SigPrefixes[i]; 370 if (sig_prefix->nid != hash_nid) { 371 continue; 372 } 373 374 const uint8_t* prefix = sig_prefix->bytes; 375 unsigned prefix_len = sig_prefix->len; 376 unsigned signed_msg_len; 377 uint8_t *signed_msg; 378 379 signed_msg_len = prefix_len + msg_len; 380 if (signed_msg_len < prefix_len) { 381 OPENSSL_PUT_ERROR(RSA, pkcs1_prefixed_msg, RSA_R_TOO_LONG); 382 return 0; 383 } 384 385 signed_msg = OPENSSL_malloc(signed_msg_len); 386 if (!signed_msg) { 387 OPENSSL_PUT_ERROR(RSA, pkcs1_prefixed_msg, ERR_R_MALLOC_FAILURE); 388 return 0; 389 } 390 391 memcpy(signed_msg, prefix, prefix_len); 392 memcpy(signed_msg + prefix_len, msg, msg_len); 393 394 *out_msg = signed_msg; 395 *out_msg_len = signed_msg_len; 396 *is_alloced = 1; 397 398 return 1; 399 } 400 401 OPENSSL_PUT_ERROR(RSA, pkcs1_prefixed_msg, RSA_R_UNKNOWN_ALGORITHM_TYPE); 402 return 0; 403 } 404 405 int RSA_sign(int hash_nid, const uint8_t *in, unsigned in_len, uint8_t *out, 406 unsigned *out_len, RSA *rsa) { 407 const unsigned rsa_size = RSA_size(rsa); 408 int ret = 0; 409 uint8_t *signed_msg; 410 size_t signed_msg_len; 411 int signed_msg_is_alloced = 0; 412 size_t size_t_out_len; 413 414 if (rsa->meth->sign) { 415 return rsa->meth->sign(hash_nid, in, in_len, out, out_len, rsa); 416 } 417 418 if (!pkcs1_prefixed_msg(&signed_msg, &signed_msg_len, &signed_msg_is_alloced, 419 hash_nid, in, in_len)) { 420 return 0; 421 } 422 423 if (rsa_size < RSA_PKCS1_PADDING_SIZE || 424 signed_msg_len > rsa_size - RSA_PKCS1_PADDING_SIZE) { 425 OPENSSL_PUT_ERROR(RSA, RSA_sign, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY); 426 goto finish; 427 } 428 429 if (RSA_sign_raw(rsa, &size_t_out_len, out, rsa_size, signed_msg, 430 signed_msg_len, RSA_PKCS1_PADDING)) { 431 *out_len = size_t_out_len; 432 ret = 1; 433 } 434 435 finish: 436 if (signed_msg_is_alloced) { 437 OPENSSL_free(signed_msg); 438 } 439 return ret; 440 } 441 442 int RSA_verify(int hash_nid, const uint8_t *msg, size_t msg_len, 443 const uint8_t *sig, size_t sig_len, RSA *rsa) { 444 const size_t rsa_size = RSA_size(rsa); 445 uint8_t *buf = NULL; 446 int ret = 0; 447 uint8_t *signed_msg = NULL; 448 size_t signed_msg_len, len; 449 int signed_msg_is_alloced = 0; 450 451 if (rsa->meth->verify) { 452 return rsa->meth->verify(hash_nid, msg, msg_len, sig, sig_len, rsa); 453 } 454 455 if (sig_len != rsa_size) { 456 OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_WRONG_SIGNATURE_LENGTH); 457 return 0; 458 } 459 460 if (hash_nid == NID_md5_sha1 && msg_len != SSL_SIG_LENGTH) { 461 OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_INVALID_MESSAGE_LENGTH); 462 return 0; 463 } 464 465 buf = OPENSSL_malloc(rsa_size); 466 if (!buf) { 467 OPENSSL_PUT_ERROR(RSA, RSA_verify, ERR_R_MALLOC_FAILURE); 468 return 0; 469 } 470 471 if (!RSA_verify_raw(rsa, &len, buf, rsa_size, sig, sig_len, 472 RSA_PKCS1_PADDING)) { 473 goto out; 474 } 475 476 if (!pkcs1_prefixed_msg(&signed_msg, &signed_msg_len, &signed_msg_is_alloced, 477 hash_nid, msg, msg_len)) { 478 goto out; 479 } 480 481 if (len != signed_msg_len || CRYPTO_memcmp(buf, signed_msg, len) != 0) { 482 OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_BAD_SIGNATURE); 483 goto out; 484 } 485 486 ret = 1; 487 488 out: 489 OPENSSL_free(buf); 490 if (signed_msg_is_alloced) { 491 OPENSSL_free(signed_msg); 492 } 493 return ret; 494 } 495 496 static void bn_free_and_null(BIGNUM **bn) { 497 BN_free(*bn); 498 *bn = NULL; 499 } 500 501 int RSA_check_key(const RSA *key) { 502 BIGNUM n, pm1, qm1, lcm, gcd, de, dmp1, dmq1, iqmp; 503 BN_CTX *ctx; 504 int ok = 0, has_crt_values; 505 506 if (RSA_is_opaque(key)) { 507 /* Opaque keys can't be checked. */ 508 return 1; 509 } 510 511 if ((key->p != NULL) != (key->q != NULL)) { 512 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_ONLY_ONE_OF_P_Q_GIVEN); 513 return 0; 514 } 515 516 if (!key->n || !key->e) { 517 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_VALUE_MISSING); 518 return 0; 519 } 520 521 if (!key->d || !key->p) { 522 /* For a public key, or without p and q, there's nothing that can be 523 * checked. */ 524 return 1; 525 } 526 527 ctx = BN_CTX_new(); 528 if (ctx == NULL) { 529 OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_R_MALLOC_FAILURE); 530 return 0; 531 } 532 533 BN_init(&n); 534 BN_init(&pm1); 535 BN_init(&qm1); 536 BN_init(&lcm); 537 BN_init(&gcd); 538 BN_init(&de); 539 BN_init(&dmp1); 540 BN_init(&dmq1); 541 BN_init(&iqmp); 542 543 if (/* n = pq */ 544 !BN_mul(&n, key->p, key->q, ctx) || 545 /* lcm = lcm(p-1, q-1) */ 546 !BN_sub(&pm1, key->p, BN_value_one()) || 547 !BN_sub(&qm1, key->q, BN_value_one()) || 548 !BN_mul(&lcm, &pm1, &qm1, ctx) || 549 !BN_gcd(&gcd, &pm1, &qm1, ctx) || 550 !BN_div(&lcm, NULL, &lcm, &gcd, ctx) || 551 /* de = d*e mod lcm(p-1, q-1) */ 552 !BN_mod_mul(&de, key->d, key->e, &lcm, ctx)) { 553 OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_LIB_BN); 554 goto out; 555 } 556 557 if (BN_cmp(&n, key->n) != 0) { 558 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_N_NOT_EQUAL_P_Q); 559 goto out; 560 } 561 562 if (!BN_is_one(&de)) { 563 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_D_E_NOT_CONGRUENT_TO_1); 564 goto out; 565 } 566 567 has_crt_values = key->dmp1 != NULL; 568 if (has_crt_values != (key->dmq1 != NULL) || 569 has_crt_values != (key->iqmp != NULL)) { 570 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_INCONSISTENT_SET_OF_CRT_VALUES); 571 goto out; 572 } 573 574 if (has_crt_values) { 575 if (/* dmp1 = d mod (p-1) */ 576 !BN_mod(&dmp1, key->d, &pm1, ctx) || 577 /* dmq1 = d mod (q-1) */ 578 !BN_mod(&dmq1, key->d, &qm1, ctx) || 579 /* iqmp = q^-1 mod p */ 580 !BN_mod_inverse(&iqmp, key->q, key->p, ctx)) { 581 OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_LIB_BN); 582 goto out; 583 } 584 585 if (BN_cmp(&dmp1, key->dmp1) != 0 || 586 BN_cmp(&dmq1, key->dmq1) != 0 || 587 BN_cmp(&iqmp, key->iqmp) != 0) { 588 OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_CRT_VALUES_INCORRECT); 589 goto out; 590 } 591 } 592 593 ok = 1; 594 595 out: 596 BN_free(&n); 597 BN_free(&pm1); 598 BN_free(&qm1); 599 BN_free(&lcm); 600 BN_free(&gcd); 601 BN_free(&de); 602 BN_free(&dmp1); 603 BN_free(&dmq1); 604 BN_free(&iqmp); 605 BN_CTX_free(ctx); 606 607 return ok; 608 } 609 610 int RSA_recover_crt_params(RSA *rsa) { 611 BN_CTX *ctx; 612 BIGNUM *totient, *rem, *multiple, *p_plus_q, *p_minus_q; 613 int ok = 0; 614 615 if (rsa->n == NULL || rsa->e == NULL || rsa->d == NULL) { 616 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_EMPTY_PUBLIC_KEY); 617 return 0; 618 } 619 620 if (rsa->p || rsa->q || rsa->dmp1 || rsa->dmq1 || rsa->iqmp) { 621 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, 622 RSA_R_CRT_PARAMS_ALREADY_GIVEN); 623 return 0; 624 } 625 626 /* This uses the algorithm from section 9B of the RSA paper: 627 * http://people.csail.mit.edu/rivest/Rsapaper.pdf */ 628 629 ctx = BN_CTX_new(); 630 if (ctx == NULL) { 631 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); 632 return 0; 633 } 634 635 BN_CTX_start(ctx); 636 totient = BN_CTX_get(ctx); 637 rem = BN_CTX_get(ctx); 638 multiple = BN_CTX_get(ctx); 639 p_plus_q = BN_CTX_get(ctx); 640 p_minus_q = BN_CTX_get(ctx); 641 642 if (totient == NULL || rem == NULL || multiple == NULL || p_plus_q == NULL || 643 p_minus_q == NULL) { 644 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); 645 goto err; 646 } 647 648 /* ed-1 is a small multiple of (n). */ 649 if (!BN_mul(totient, rsa->e, rsa->d, ctx) || 650 !BN_sub_word(totient, 1) || 651 /* (n) = 652 * pq - p - q + 1 = 653 * n - (p + q) + 1 654 * 655 * Thus n is a reasonable estimate for (n). So, (ed-1)/n will be very 656 * close. But, when we calculate the quotient, we'll be truncating it 657 * because we discard the remainder. Thus (ed-1)/multiple will be >= n, 658 * which the totient cannot be. So we add one to the estimate. 659 * 660 * Consider ed-1 as: 661 * 662 * multiple * (n - (p+q) + 1) = 663 * multiple*n - multiple*(p+q) + multiple 664 * 665 * When we divide by n, the first term becomes multiple and, since 666 * multiple and p+q is tiny compared to n, the second and third terms can 667 * be ignored. Thus I claim that subtracting one from the estimate is 668 * sufficient. */ 669 !BN_div(multiple, NULL, totient, rsa->n, ctx) || 670 !BN_add_word(multiple, 1) || 671 !BN_div(totient, rem, totient, multiple, ctx)) { 672 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); 673 goto err; 674 } 675 676 if (!BN_is_zero(rem)) { 677 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_BAD_RSA_PARAMETERS); 678 goto err; 679 } 680 681 rsa->p = BN_new(); 682 rsa->q = BN_new(); 683 rsa->dmp1 = BN_new(); 684 rsa->dmq1 = BN_new(); 685 rsa->iqmp = BN_new(); 686 if (rsa->p == NULL || rsa->q == NULL || rsa->dmp1 == NULL || rsa->dmq1 == 687 NULL || rsa->iqmp == NULL) { 688 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); 689 goto err; 690 } 691 692 /* (n) = n - (p + q) + 1 => 693 * n - totient + 1 = p + q */ 694 if (!BN_sub(p_plus_q, rsa->n, totient) || 695 !BN_add_word(p_plus_q, 1) || 696 /* p - q = sqrt((p+q)^2 - 4n) */ 697 !BN_sqr(rem, p_plus_q, ctx) || 698 !BN_lshift(multiple, rsa->n, 2) || 699 !BN_sub(rem, rem, multiple) || 700 !BN_sqrt(p_minus_q, rem, ctx) || 701 /* q is 1/2 (p+q)-(p-q) */ 702 !BN_sub(rsa->q, p_plus_q, p_minus_q) || 703 !BN_rshift1(rsa->q, rsa->q) || 704 !BN_div(rsa->p, NULL, rsa->n, rsa->q, ctx) || 705 !BN_mul(multiple, rsa->p, rsa->q, ctx)) { 706 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); 707 goto err; 708 } 709 710 if (BN_cmp(multiple, rsa->n) != 0) { 711 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_INTERNAL_ERROR); 712 goto err; 713 } 714 715 if (!BN_sub(rem, rsa->p, BN_value_one()) || 716 !BN_mod(rsa->dmp1, rsa->d, rem, ctx) || 717 !BN_sub(rem, rsa->q, BN_value_one()) || 718 !BN_mod(rsa->dmq1, rsa->d, rem, ctx) || 719 !BN_mod_inverse(rsa->iqmp, rsa->q, rsa->p, ctx)) { 720 OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); 721 goto err; 722 } 723 724 ok = 1; 725 726 err: 727 BN_CTX_end(ctx); 728 BN_CTX_free(ctx); 729 if (!ok) { 730 bn_free_and_null(&rsa->p); 731 bn_free_and_null(&rsa->q); 732 bn_free_and_null(&rsa->dmp1); 733 bn_free_and_null(&rsa->dmq1); 734 bn_free_and_null(&rsa->iqmp); 735 } 736 return ok; 737 } 738 739 int RSA_private_transform(RSA *rsa, uint8_t *out, const uint8_t *in, 740 size_t len) { 741 if (rsa->meth->private_transform) { 742 return rsa->meth->private_transform(rsa, out, in, len); 743 } 744 745 return RSA_default_method.private_transform(rsa, out, in, len); 746 } 747 748 int RSA_blinding_on(RSA *rsa, BN_CTX *ctx) { 749 return 1; 750 } 751
