1 /* $OpenBSD: rsa_eay.c,v 1.51 2019/11/02 13:52:31 jsing Exp $ */ 2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 /* ==================================================================== 59 * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved. 60 * 61 * Redistribution and use in source and binary forms, with or without 62 * modification, are permitted provided that the following conditions 63 * are met: 64 * 65 * 1. Redistributions of source code must retain the above copyright 66 * notice, this list of conditions and the following disclaimer. 67 * 68 * 2. Redistributions in binary form must reproduce the above copyright 69 * notice, this list of conditions and the following disclaimer in 70 * the documentation and/or other materials provided with the 71 * distribution. 72 * 73 * 3. All advertising materials mentioning features or use of this 74 * software must display the following acknowledgment: 75 * "This product includes software developed by the OpenSSL Project 76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 77 * 78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 79 * endorse or promote products derived from this software without 80 * prior written permission. For written permission, please contact 81 * openssl-core@openssl.org. 82 * 83 * 5. Products derived from this software may not be called "OpenSSL" 84 * nor may "OpenSSL" appear in their names without prior written 85 * permission of the OpenSSL Project. 86 * 87 * 6. Redistributions of any form whatsoever must retain the following 88 * acknowledgment: 89 * "This product includes software developed by the OpenSSL Project 90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 91 * 92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 103 * OF THE POSSIBILITY OF SUCH DAMAGE. 104 * ==================================================================== 105 * 106 * This product includes cryptographic software written by Eric Young 107 * (eay@cryptsoft.com). This product includes software written by Tim 108 * Hudson (tjh@cryptsoft.com). 109 * 110 */ 111 112 #include <stdio.h> 113 #include <string.h> 114 115 #include <openssl/opensslconf.h> 116 117 #include <openssl/bn.h> 118 #include <openssl/err.h> 119 #include <openssl/rsa.h> 120 121 #include "bn_lcl.h" 122 123 static int RSA_eay_public_encrypt(int flen, const unsigned char *from, 124 unsigned char *to, RSA *rsa, int padding); 125 static int RSA_eay_private_encrypt(int flen, const unsigned char *from, 126 unsigned char *to, RSA *rsa, int padding); 127 static int RSA_eay_public_decrypt(int flen, const unsigned char *from, 128 unsigned char *to, RSA *rsa, int padding); 129 static int RSA_eay_private_decrypt(int flen, const unsigned char *from, 130 unsigned char *to, RSA *rsa, int padding); 131 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx); 132 static int RSA_eay_init(RSA *rsa); 133 static int RSA_eay_finish(RSA *rsa); 134 135 static RSA_METHOD rsa_pkcs1_eay_meth = { 136 .name = "Eric Young's PKCS#1 RSA", 137 .rsa_pub_enc = RSA_eay_public_encrypt, 138 .rsa_pub_dec = RSA_eay_public_decrypt, /* signature verification */ 139 .rsa_priv_enc = RSA_eay_private_encrypt, /* signing */ 140 .rsa_priv_dec = RSA_eay_private_decrypt, 141 .rsa_mod_exp = RSA_eay_mod_exp, 142 .bn_mod_exp = BN_mod_exp_mont_ct, /* XXX probably we should not use Montgomery if e == 3 */ 143 .init = RSA_eay_init, 144 .finish = RSA_eay_finish, 145 }; 146 147 const RSA_METHOD * 148 RSA_PKCS1_OpenSSL(void) 149 { 150 return &rsa_pkcs1_eay_meth; 151 } 152 153 const RSA_METHOD * 154 RSA_PKCS1_SSLeay(void) 155 { 156 return &rsa_pkcs1_eay_meth; 157 } 158 159 static int 160 RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *to, 161 RSA *rsa, int padding) 162 { 163 BIGNUM *f, *ret; 164 int i, j, k, num = 0, r = -1; 165 unsigned char *buf = NULL; 166 BN_CTX *ctx = NULL; 167 168 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 169 RSAerror(RSA_R_MODULUS_TOO_LARGE); 170 return -1; 171 } 172 173 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 174 RSAerror(RSA_R_BAD_E_VALUE); 175 return -1; 176 } 177 178 /* for large moduli, enforce exponent limit */ 179 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 180 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 181 RSAerror(RSA_R_BAD_E_VALUE); 182 return -1; 183 } 184 } 185 186 if ((ctx = BN_CTX_new()) == NULL) 187 goto err; 188 189 BN_CTX_start(ctx); 190 f = BN_CTX_get(ctx); 191 ret = BN_CTX_get(ctx); 192 num = BN_num_bytes(rsa->n); 193 buf = malloc(num); 194 195 if (f == NULL || ret == NULL || buf == NULL) { 196 RSAerror(ERR_R_MALLOC_FAILURE); 197 goto err; 198 } 199 200 switch (padding) { 201 case RSA_PKCS1_PADDING: 202 i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen); 203 break; 204 #ifndef OPENSSL_NO_SHA 205 case RSA_PKCS1_OAEP_PADDING: 206 i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0); 207 break; 208 #endif 209 case RSA_NO_PADDING: 210 i = RSA_padding_add_none(buf, num, from, flen); 211 break; 212 default: 213 RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); 214 goto err; 215 } 216 if (i <= 0) 217 goto err; 218 219 if (BN_bin2bn(buf, num, f) == NULL) 220 goto err; 221 222 if (BN_ucmp(f, rsa->n) >= 0) { 223 /* usually the padding functions would catch this */ 224 RSAerror(RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 225 goto err; 226 } 227 228 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 229 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 230 CRYPTO_LOCK_RSA, rsa->n, ctx)) 231 goto err; 232 233 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 234 rsa->_method_mod_n)) 235 goto err; 236 237 /* put in leading 0 bytes if the number is less than the 238 * length of the modulus */ 239 j = BN_num_bytes(ret); 240 i = BN_bn2bin(ret, &(to[num - j])); 241 for (k = 0; k < num - i; k++) 242 to[k] = 0; 243 244 r = num; 245 err: 246 if (ctx != NULL) { 247 BN_CTX_end(ctx); 248 BN_CTX_free(ctx); 249 } 250 freezero(buf, num); 251 return r; 252 } 253 254 static BN_BLINDING * 255 rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx) 256 { 257 BN_BLINDING *ret; 258 int got_write_lock = 0; 259 CRYPTO_THREADID cur; 260 261 CRYPTO_r_lock(CRYPTO_LOCK_RSA); 262 263 if (rsa->blinding == NULL) { 264 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 265 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 266 got_write_lock = 1; 267 268 if (rsa->blinding == NULL) 269 rsa->blinding = RSA_setup_blinding(rsa, ctx); 270 } 271 272 ret = rsa->blinding; 273 if (ret == NULL) 274 goto err; 275 276 CRYPTO_THREADID_current(&cur); 277 if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) { 278 /* rsa->blinding is ours! */ 279 *local = 1; 280 } else { 281 /* resort to rsa->mt_blinding instead */ 282 /* 283 * Instruct rsa_blinding_convert(), rsa_blinding_invert() 284 * that the BN_BLINDING is shared, meaning that accesses 285 * require locks, and that the blinding factor must be 286 * stored outside the BN_BLINDING 287 */ 288 *local = 0; 289 290 if (rsa->mt_blinding == NULL) { 291 if (!got_write_lock) { 292 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 293 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 294 got_write_lock = 1; 295 } 296 297 if (rsa->mt_blinding == NULL) 298 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx); 299 } 300 ret = rsa->mt_blinding; 301 } 302 303 err: 304 if (got_write_lock) 305 CRYPTO_w_unlock(CRYPTO_LOCK_RSA); 306 else 307 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 308 return ret; 309 } 310 311 static int 312 rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) 313 { 314 if (unblind == NULL) 315 /* 316 * Local blinding: store the unblinding factor 317 * in BN_BLINDING. 318 */ 319 return BN_BLINDING_convert_ex(f, NULL, b, ctx); 320 else { 321 /* 322 * Shared blinding: store the unblinding factor 323 * outside BN_BLINDING. 324 */ 325 int ret; 326 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING); 327 ret = BN_BLINDING_convert_ex(f, unblind, b, ctx); 328 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); 329 return ret; 330 } 331 } 332 333 static int 334 rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) 335 { 336 /* 337 * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex 338 * will use the unblinding factor stored in BN_BLINDING. 339 * If BN_BLINDING is shared between threads, unblind must be non-null: 340 * BN_BLINDING_invert_ex will then use the local unblinding factor, 341 * and will only read the modulus from BN_BLINDING. 342 * In both cases it's safe to access the blinding without a lock. 343 */ 344 return BN_BLINDING_invert_ex(f, unblind, b, ctx); 345 } 346 347 /* signing */ 348 static int 349 RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to, 350 RSA *rsa, int padding) 351 { 352 BIGNUM *f, *ret, *res; 353 int i, j, k, num = 0, r = -1; 354 unsigned char *buf = NULL; 355 BN_CTX *ctx = NULL; 356 int local_blinding = 0; 357 /* 358 * Used only if the blinding structure is shared. A non-NULL unblind 359 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 360 * the unblinding factor outside the blinding structure. 361 */ 362 BIGNUM *unblind = NULL; 363 BN_BLINDING *blinding = NULL; 364 365 if ((ctx = BN_CTX_new()) == NULL) 366 goto err; 367 368 BN_CTX_start(ctx); 369 f = BN_CTX_get(ctx); 370 ret = BN_CTX_get(ctx); 371 num = BN_num_bytes(rsa->n); 372 buf = malloc(num); 373 374 if (f == NULL || ret == NULL || buf == NULL) { 375 RSAerror(ERR_R_MALLOC_FAILURE); 376 goto err; 377 } 378 379 switch (padding) { 380 case RSA_PKCS1_PADDING: 381 i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen); 382 break; 383 case RSA_X931_PADDING: 384 i = RSA_padding_add_X931(buf, num, from, flen); 385 break; 386 case RSA_NO_PADDING: 387 i = RSA_padding_add_none(buf, num, from, flen); 388 break; 389 default: 390 RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); 391 goto err; 392 } 393 if (i <= 0) 394 goto err; 395 396 if (BN_bin2bn(buf, num, f) == NULL) 397 goto err; 398 399 if (BN_ucmp(f, rsa->n) >= 0) { 400 /* usually the padding functions would catch this */ 401 RSAerror(RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 402 goto err; 403 } 404 405 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 406 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 407 if (blinding == NULL) { 408 RSAerror(ERR_R_INTERNAL_ERROR); 409 goto err; 410 } 411 } 412 413 if (blinding != NULL) { 414 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 415 RSAerror(ERR_R_MALLOC_FAILURE); 416 goto err; 417 } 418 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 419 goto err; 420 } 421 422 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 423 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 424 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 425 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 426 goto err; 427 } else { 428 BIGNUM d; 429 430 BN_init(&d); 431 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 432 433 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 434 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 435 CRYPTO_LOCK_RSA, rsa->n, ctx)) 436 goto err; 437 438 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 439 rsa->_method_mod_n)) { 440 goto err; 441 } 442 } 443 444 if (blinding) 445 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 446 goto err; 447 448 if (padding == RSA_X931_PADDING) { 449 BN_sub(f, rsa->n, ret); 450 if (BN_cmp(ret, f) > 0) 451 res = f; 452 else 453 res = ret; 454 } else 455 res = ret; 456 457 /* put in leading 0 bytes if the number is less than the 458 * length of the modulus */ 459 j = BN_num_bytes(res); 460 i = BN_bn2bin(res, &(to[num - j])); 461 for (k = 0; k < num - i; k++) 462 to[k] = 0; 463 464 r = num; 465 err: 466 if (ctx != NULL) { 467 BN_CTX_end(ctx); 468 BN_CTX_free(ctx); 469 } 470 freezero(buf, num); 471 return r; 472 } 473 474 static int 475 RSA_eay_private_decrypt(int flen, const unsigned char *from, unsigned char *to, 476 RSA *rsa, int padding) 477 { 478 BIGNUM *f, *ret; 479 int j, num = 0, r = -1; 480 unsigned char *p; 481 unsigned char *buf = NULL; 482 BN_CTX *ctx = NULL; 483 int local_blinding = 0; 484 /* 485 * Used only if the blinding structure is shared. A non-NULL unblind 486 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 487 * the unblinding factor outside the blinding structure. 488 */ 489 BIGNUM *unblind = NULL; 490 BN_BLINDING *blinding = NULL; 491 492 if ((ctx = BN_CTX_new()) == NULL) 493 goto err; 494 495 BN_CTX_start(ctx); 496 f = BN_CTX_get(ctx); 497 ret = BN_CTX_get(ctx); 498 num = BN_num_bytes(rsa->n); 499 buf = malloc(num); 500 501 if (!f || !ret || !buf) { 502 RSAerror(ERR_R_MALLOC_FAILURE); 503 goto err; 504 } 505 506 /* This check was for equality but PGP does evil things 507 * and chops off the top '0' bytes */ 508 if (flen > num) { 509 RSAerror(RSA_R_DATA_GREATER_THAN_MOD_LEN); 510 goto err; 511 } 512 513 /* make data into a big number */ 514 if (BN_bin2bn(from, (int)flen, f) == NULL) 515 goto err; 516 517 if (BN_ucmp(f, rsa->n) >= 0) { 518 RSAerror(RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 519 goto err; 520 } 521 522 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 523 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 524 if (blinding == NULL) { 525 RSAerror(ERR_R_INTERNAL_ERROR); 526 goto err; 527 } 528 } 529 530 if (blinding != NULL) { 531 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 532 RSAerror(ERR_R_MALLOC_FAILURE); 533 goto err; 534 } 535 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 536 goto err; 537 } 538 539 /* do the decrypt */ 540 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 541 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 542 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 543 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 544 goto err; 545 } else { 546 BIGNUM d; 547 548 BN_init(&d); 549 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 550 551 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 552 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 553 CRYPTO_LOCK_RSA, rsa->n, ctx)) 554 goto err; 555 556 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 557 rsa->_method_mod_n)) { 558 goto err; 559 } 560 } 561 562 if (blinding) 563 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 564 goto err; 565 566 p = buf; 567 j = BN_bn2bin(ret, p); /* j is only used with no-padding mode */ 568 569 switch (padding) { 570 case RSA_PKCS1_PADDING: 571 r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num); 572 break; 573 #ifndef OPENSSL_NO_SHA 574 case RSA_PKCS1_OAEP_PADDING: 575 r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0); 576 break; 577 #endif 578 case RSA_NO_PADDING: 579 r = RSA_padding_check_none(to, num, buf, j, num); 580 break; 581 default: 582 RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); 583 goto err; 584 } 585 if (r < 0) 586 RSAerror(RSA_R_PADDING_CHECK_FAILED); 587 588 err: 589 if (ctx != NULL) { 590 BN_CTX_end(ctx); 591 BN_CTX_free(ctx); 592 } 593 freezero(buf, num); 594 return r; 595 } 596 597 /* signature verification */ 598 static int 599 RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to, 600 RSA *rsa, int padding) 601 { 602 BIGNUM *f, *ret; 603 int i, num = 0, r = -1; 604 unsigned char *p; 605 unsigned char *buf = NULL; 606 BN_CTX *ctx = NULL; 607 608 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 609 RSAerror(RSA_R_MODULUS_TOO_LARGE); 610 return -1; 611 } 612 613 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 614 RSAerror(RSA_R_BAD_E_VALUE); 615 return -1; 616 } 617 618 /* for large moduli, enforce exponent limit */ 619 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 620 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 621 RSAerror(RSA_R_BAD_E_VALUE); 622 return -1; 623 } 624 } 625 626 if ((ctx = BN_CTX_new()) == NULL) 627 goto err; 628 629 BN_CTX_start(ctx); 630 f = BN_CTX_get(ctx); 631 ret = BN_CTX_get(ctx); 632 num = BN_num_bytes(rsa->n); 633 buf = malloc(num); 634 635 if (!f || !ret || !buf) { 636 RSAerror(ERR_R_MALLOC_FAILURE); 637 goto err; 638 } 639 640 /* This check was for equality but PGP does evil things 641 * and chops off the top '0' bytes */ 642 if (flen > num) { 643 RSAerror(RSA_R_DATA_GREATER_THAN_MOD_LEN); 644 goto err; 645 } 646 647 if (BN_bin2bn(from, flen, f) == NULL) 648 goto err; 649 650 if (BN_ucmp(f, rsa->n) >= 0) { 651 RSAerror(RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 652 goto err; 653 } 654 655 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 656 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 657 CRYPTO_LOCK_RSA, rsa->n, ctx)) 658 goto err; 659 660 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 661 rsa->_method_mod_n)) 662 goto err; 663 664 if (padding == RSA_X931_PADDING && (ret->d[0] & 0xf) != 12) 665 if (!BN_sub(ret, rsa->n, ret)) 666 goto err; 667 668 p = buf; 669 i = BN_bn2bin(ret, p); 670 671 switch (padding) { 672 case RSA_PKCS1_PADDING: 673 r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num); 674 break; 675 case RSA_X931_PADDING: 676 r = RSA_padding_check_X931(to, num, buf, i, num); 677 break; 678 case RSA_NO_PADDING: 679 r = RSA_padding_check_none(to, num, buf, i, num); 680 break; 681 default: 682 RSAerror(RSA_R_UNKNOWN_PADDING_TYPE); 683 goto err; 684 } 685 if (r < 0) 686 RSAerror(RSA_R_PADDING_CHECK_FAILED); 687 688 err: 689 if (ctx != NULL) { 690 BN_CTX_end(ctx); 691 BN_CTX_free(ctx); 692 } 693 freezero(buf, num); 694 return r; 695 } 696 697 static int 698 RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) 699 { 700 BIGNUM *r1, *m1, *vrfy; 701 BIGNUM dmp1, dmq1, c, pr1; 702 int ret = 0; 703 704 BN_CTX_start(ctx); 705 r1 = BN_CTX_get(ctx); 706 m1 = BN_CTX_get(ctx); 707 vrfy = BN_CTX_get(ctx); 708 if (r1 == NULL || m1 == NULL || vrfy == NULL) { 709 RSAerror(ERR_R_MALLOC_FAILURE); 710 goto err; 711 } 712 713 { 714 BIGNUM p, q; 715 716 /* 717 * Make sure BN_mod_inverse in Montgomery intialization uses the 718 * BN_FLG_CONSTTIME flag 719 */ 720 BN_init(&p); 721 BN_init(&q); 722 BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME); 723 BN_with_flags(&q, rsa->q, BN_FLG_CONSTTIME); 724 725 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { 726 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, 727 CRYPTO_LOCK_RSA, &p, ctx) || 728 !BN_MONT_CTX_set_locked(&rsa->_method_mod_q, 729 CRYPTO_LOCK_RSA, &q, ctx)) { 730 goto err; 731 } 732 } 733 } 734 735 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 736 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 737 CRYPTO_LOCK_RSA, rsa->n, ctx)) 738 goto err; 739 740 /* compute I mod q */ 741 BN_init(&c); 742 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 743 744 if (!BN_mod_ct(r1, &c, rsa->q, ctx)) 745 goto err; 746 747 /* compute r1^dmq1 mod q */ 748 BN_init(&dmq1); 749 BN_with_flags(&dmq1, rsa->dmq1, BN_FLG_CONSTTIME); 750 751 if (!rsa->meth->bn_mod_exp(m1, r1, &dmq1, rsa->q, ctx, 752 rsa->_method_mod_q)) 753 goto err; 754 755 /* compute I mod p */ 756 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 757 758 if (!BN_mod_ct(r1, &c, rsa->p, ctx)) 759 goto err; 760 761 /* compute r1^dmp1 mod p */ 762 BN_init(&dmp1); 763 BN_with_flags(&dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 764 765 if (!rsa->meth->bn_mod_exp(r0, r1, &dmp1, rsa->p, ctx, 766 rsa->_method_mod_p)) 767 goto err; 768 769 if (!BN_sub(r0, r0, m1)) 770 goto err; 771 772 /* 773 * This will help stop the size of r0 increasing, which does 774 * affect the multiply if it optimised for a power of 2 size 775 */ 776 if (BN_is_negative(r0)) 777 if (!BN_add(r0, r0, rsa->p)) 778 goto err; 779 780 if (!BN_mul(r1, r0, rsa->iqmp, ctx)) 781 goto err; 782 783 /* Turn BN_FLG_CONSTTIME flag on before division operation */ 784 BN_init(&pr1); 785 BN_with_flags(&pr1, r1, BN_FLG_CONSTTIME); 786 787 if (!BN_mod_ct(r0, &pr1, rsa->p, ctx)) 788 goto err; 789 790 /* 791 * If p < q it is occasionally possible for the correction of 792 * adding 'p' if r0 is negative above to leave the result still 793 * negative. This can break the private key operations: the following 794 * second correction should *always* correct this rare occurrence. 795 * This will *never* happen with OpenSSL generated keys because 796 * they ensure p > q [steve] 797 */ 798 if (BN_is_negative(r0)) 799 if (!BN_add(r0, r0, rsa->p)) 800 goto err; 801 if (!BN_mul(r1, r0, rsa->q, ctx)) 802 goto err; 803 if (!BN_add(r0, r1, m1)) 804 goto err; 805 806 if (rsa->e && rsa->n) { 807 if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx, 808 rsa->_method_mod_n)) 809 goto err; 810 /* 811 * If 'I' was greater than (or equal to) rsa->n, the operation 812 * will be equivalent to using 'I mod n'. However, the result of 813 * the verify will *always* be less than 'n' so we don't check 814 * for absolute equality, just congruency. 815 */ 816 if (!BN_sub(vrfy, vrfy, I)) 817 goto err; 818 if (!BN_mod_ct(vrfy, vrfy, rsa->n, ctx)) 819 goto err; 820 if (BN_is_negative(vrfy)) 821 if (!BN_add(vrfy, vrfy, rsa->n)) 822 goto err; 823 if (!BN_is_zero(vrfy)) { 824 /* 825 * 'I' and 'vrfy' aren't congruent mod n. Don't leak 826 * miscalculated CRT output, just do a raw (slower) 827 * mod_exp and return that instead. 828 */ 829 BIGNUM d; 830 831 BN_init(&d); 832 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 833 834 if (!rsa->meth->bn_mod_exp(r0, I, &d, rsa->n, ctx, 835 rsa->_method_mod_n)) { 836 goto err; 837 } 838 } 839 } 840 ret = 1; 841 err: 842 BN_CTX_end(ctx); 843 return ret; 844 } 845 846 static int 847 RSA_eay_init(RSA *rsa) 848 { 849 rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE; 850 return 1; 851 } 852 853 static int 854 RSA_eay_finish(RSA *rsa) 855 { 856 BN_MONT_CTX_free(rsa->_method_mod_n); 857 BN_MONT_CTX_free(rsa->_method_mod_p); 858 BN_MONT_CTX_free(rsa->_method_mod_q); 859 860 return 1; 861 } 862