rsa_eay.c revision 344604
1/* crypto/rsa/rsa_eay.c */ 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) 1998-2018 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 "cryptlib.h" 114#include <openssl/bn.h> 115#include <openssl/rsa.h> 116#include <openssl/rand.h> 117#include "bn_int.h" 118#include "constant_time_locl.h" 119 120#ifndef RSA_NULL 121 122static int RSA_eay_public_encrypt(int flen, const unsigned char *from, 123 unsigned char *to, RSA *rsa, int padding); 124static int RSA_eay_private_encrypt(int flen, const unsigned char *from, 125 unsigned char *to, RSA *rsa, int padding); 126static int RSA_eay_public_decrypt(int flen, const unsigned char *from, 127 unsigned char *to, RSA *rsa, int padding); 128static int RSA_eay_private_decrypt(int flen, const unsigned char *from, 129 unsigned char *to, RSA *rsa, int padding); 130static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, 131 BN_CTX *ctx); 132static int RSA_eay_init(RSA *rsa); 133static int RSA_eay_finish(RSA *rsa); 134static RSA_METHOD rsa_pkcs1_eay_meth = { 135 "Eric Young's PKCS#1 RSA", 136 RSA_eay_public_encrypt, 137 RSA_eay_public_decrypt, /* signature verification */ 138 RSA_eay_private_encrypt, /* signing */ 139 RSA_eay_private_decrypt, 140 RSA_eay_mod_exp, 141 BN_mod_exp_mont, /* XXX probably we should not use Montgomery 142 * if e == 3 */ 143 RSA_eay_init, 144 RSA_eay_finish, 145 0, /* flags */ 146 NULL, 147 0, /* rsa_sign */ 148 0, /* rsa_verify */ 149 NULL /* rsa_keygen */ 150}; 151 152const RSA_METHOD *RSA_PKCS1_SSLeay(void) 153{ 154 return (&rsa_pkcs1_eay_meth); 155} 156 157static int RSA_eay_public_encrypt(int flen, const unsigned char *from, 158 unsigned char *to, RSA *rsa, int padding) 159{ 160 BIGNUM *f, *ret; 161 int i, num = 0, r = -1; 162 unsigned char *buf = NULL; 163 BN_CTX *ctx = NULL; 164 165 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 166 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE); 167 return -1; 168 } 169 170 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 171 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 172 return -1; 173 } 174 175 /* for large moduli, enforce exponent limit */ 176 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 177 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 178 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 179 return -1; 180 } 181 } 182 183 if ((ctx = BN_CTX_new()) == NULL) 184 goto err; 185 BN_CTX_start(ctx); 186 f = BN_CTX_get(ctx); 187 ret = BN_CTX_get(ctx); 188 num = BN_num_bytes(rsa->n); 189 buf = OPENSSL_malloc(num); 190 if (!f || !ret || !buf) { 191 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE); 192 goto err; 193 } 194 195 switch (padding) { 196 case RSA_PKCS1_PADDING: 197 i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen); 198 break; 199# ifndef OPENSSL_NO_SHA 200 case RSA_PKCS1_OAEP_PADDING: 201 i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0); 202 break; 203# endif 204 case RSA_SSLV23_PADDING: 205 i = RSA_padding_add_SSLv23(buf, num, from, flen); 206 break; 207 case RSA_NO_PADDING: 208 i = RSA_padding_add_none(buf, num, from, flen); 209 break; 210 default: 211 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE); 212 goto err; 213 } 214 if (i <= 0) 215 goto err; 216 217 if (BN_bin2bn(buf, num, f) == NULL) 218 goto err; 219 220 if (BN_ucmp(f, rsa->n) >= 0) { 221 /* usually the padding functions would catch this */ 222 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, 223 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 224 goto err; 225 } 226 227 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 228 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, 229 rsa->n, ctx)) 230 goto err; 231 232 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 233 rsa->_method_mod_n)) 234 goto err; 235 236 /* 237 * BN_bn2binpad puts in leading 0 bytes if the number is less than 238 * the length of the modulus. 239 */ 240 r = bn_bn2binpad(ret, to, num); 241 err: 242 if (ctx != NULL) { 243 BN_CTX_end(ctx); 244 BN_CTX_free(ctx); 245 } 246 if (buf != NULL) { 247 OPENSSL_cleanse(buf, num); 248 OPENSSL_free(buf); 249 } 250 return (r); 251} 252 253static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx) 254{ 255 BN_BLINDING *ret; 256 int got_write_lock = 0; 257 CRYPTO_THREADID cur; 258 259 CRYPTO_r_lock(CRYPTO_LOCK_RSA); 260 261 if (rsa->blinding == NULL) { 262 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 263 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 264 got_write_lock = 1; 265 266 if (rsa->blinding == NULL) 267 rsa->blinding = RSA_setup_blinding(rsa, ctx); 268 } 269 270 ret = rsa->blinding; 271 if (ret == NULL) 272 goto err; 273 274 CRYPTO_THREADID_current(&cur); 275 if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) { 276 /* rsa->blinding is ours! */ 277 278 *local = 1; 279 } else { 280 /* resort to rsa->mt_blinding instead */ 281 282 /* 283 * instructs rsa_blinding_convert(), rsa_blinding_invert() that the 284 * BN_BLINDING is shared, meaning that accesses require locks, and 285 * that the blinding factor must be stored outside the BN_BLINDING 286 */ 287 *local = 0; 288 289 if (rsa->mt_blinding == NULL) { 290 if (!got_write_lock) { 291 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 292 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 293 got_write_lock = 1; 294 } 295 296 if (rsa->mt_blinding == NULL) 297 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx); 298 } 299 ret = rsa->mt_blinding; 300 } 301 302 err: 303 if (got_write_lock) 304 CRYPTO_w_unlock(CRYPTO_LOCK_RSA); 305 else 306 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 307 return ret; 308} 309 310static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, 311 BN_CTX *ctx) 312{ 313 if (unblind == NULL) 314 /* 315 * Local blinding: store the unblinding factor in BN_BLINDING. 316 */ 317 return BN_BLINDING_convert_ex(f, NULL, b, ctx); 318 else { 319 /* 320 * Shared blinding: store the unblinding factor outside BN_BLINDING. 321 */ 322 int ret; 323 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING); 324 ret = BN_BLINDING_convert_ex(f, unblind, b, ctx); 325 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); 326 return ret; 327 } 328} 329 330static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, 331 BN_CTX *ctx) 332{ 333 /* 334 * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex 335 * will use the unblinding factor stored in BN_BLINDING. If BN_BLINDING 336 * is shared between threads, unblind must be non-null: 337 * BN_BLINDING_invert_ex will then use the local unblinding factor, and 338 * will only read the modulus from BN_BLINDING. In both cases it's safe 339 * to access the blinding without a lock. 340 */ 341 return BN_BLINDING_invert_ex(f, unblind, b, ctx); 342} 343 344/* signing */ 345static int RSA_eay_private_encrypt(int flen, const unsigned char *from, 346 unsigned char *to, RSA *rsa, int padding) 347{ 348 BIGNUM *f, *ret, *res; 349 int i, num = 0, r = -1; 350 unsigned char *buf = NULL; 351 BN_CTX *ctx = NULL; 352 int local_blinding = 0; 353 /* 354 * Used only if the blinding structure is shared. A non-NULL unblind 355 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 356 * the unblinding factor outside the blinding structure. 357 */ 358 BIGNUM *unblind = NULL; 359 BN_BLINDING *blinding = NULL; 360 361 if ((ctx = BN_CTX_new()) == NULL) 362 goto err; 363 BN_CTX_start(ctx); 364 f = BN_CTX_get(ctx); 365 ret = BN_CTX_get(ctx); 366 num = BN_num_bytes(rsa->n); 367 buf = OPENSSL_malloc(num); 368 if (!f || !ret || !buf) { 369 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE); 370 goto err; 371 } 372 373 switch (padding) { 374 case RSA_PKCS1_PADDING: 375 i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen); 376 break; 377 case RSA_X931_PADDING: 378 i = RSA_padding_add_X931(buf, num, from, flen); 379 break; 380 case RSA_NO_PADDING: 381 i = RSA_padding_add_none(buf, num, from, flen); 382 break; 383 case RSA_SSLV23_PADDING: 384 default: 385 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE); 386 goto err; 387 } 388 if (i <= 0) 389 goto err; 390 391 if (BN_bin2bn(buf, num, f) == NULL) 392 goto err; 393 394 if (BN_ucmp(f, rsa->n) >= 0) { 395 /* usually the padding functions would catch this */ 396 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 397 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 398 goto err; 399 } 400 401 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 402 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, 403 rsa->n, ctx)) 404 goto err; 405 406 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 407 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 408 if (blinding == NULL) { 409 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR); 410 goto err; 411 } 412 } 413 414 if (blinding != NULL) { 415 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 416 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE); 417 goto err; 418 } 419 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 420 goto err; 421 } 422 423 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 424 ((rsa->p != NULL) && 425 (rsa->q != NULL) && 426 (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) { 427 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 428 goto err; 429 } else { 430 BIGNUM local_d; 431 BIGNUM *d = NULL; 432 433 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 434 BN_init(&local_d); 435 d = &local_d; 436 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); 437 } else 438 d = rsa->d; 439 440 if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx, 441 rsa->_method_mod_n)) 442 goto err; 443 } 444 445 if (blinding) 446 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 447 goto err; 448 449 if (padding == RSA_X931_PADDING) { 450 BN_sub(f, rsa->n, ret); 451 if (BN_cmp(ret, f) > 0) 452 res = f; 453 else 454 res = ret; 455 } else 456 res = ret; 457 458 /* 459 * BN_bn2binpad puts in leading 0 bytes if the number is less than 460 * the length of the modulus. 461 */ 462 r = bn_bn2binpad(res, to, num); 463 err: 464 if (ctx != NULL) { 465 BN_CTX_end(ctx); 466 BN_CTX_free(ctx); 467 } 468 if (buf != NULL) { 469 OPENSSL_cleanse(buf, num); 470 OPENSSL_free(buf); 471 } 472 return (r); 473} 474 475static int RSA_eay_private_decrypt(int flen, const unsigned char *from, 476 unsigned char *to, RSA *rsa, int padding) 477{ 478 BIGNUM *f, *ret; 479 int j, num = 0, r = -1; 480 unsigned char *buf = NULL; 481 BN_CTX *ctx = NULL; 482 int local_blinding = 0; 483 /* 484 * Used only if the blinding structure is shared. A non-NULL unblind 485 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 486 * the unblinding factor outside the blinding structure. 487 */ 488 BIGNUM *unblind = NULL; 489 BN_BLINDING *blinding = NULL; 490 491 if ((ctx = BN_CTX_new()) == NULL) 492 goto err; 493 BN_CTX_start(ctx); 494 f = BN_CTX_get(ctx); 495 ret = BN_CTX_get(ctx); 496 num = BN_num_bytes(rsa->n); 497 buf = OPENSSL_malloc(num); 498 if (!f || !ret || !buf) { 499 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE); 500 goto err; 501 } 502 503 /* 504 * This check was for equality but PGP does evil things and chops off the 505 * top '0' bytes 506 */ 507 if (flen > num) { 508 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 509 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 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 519 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 520 goto err; 521 } 522 523 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 524 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 525 if (blinding == NULL) { 526 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR); 527 goto err; 528 } 529 } 530 531 if (blinding != NULL) { 532 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 533 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE); 534 goto err; 535 } 536 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 537 goto err; 538 } 539 540 /* do the decrypt */ 541 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 542 ((rsa->p != NULL) && 543 (rsa->q != NULL) && 544 (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) { 545 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 546 goto err; 547 } else { 548 BIGNUM local_d; 549 BIGNUM *d = NULL; 550 551 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 552 d = &local_d; 553 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); 554 } else 555 d = rsa->d; 556 557 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 558 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, 559 rsa->n, ctx)) 560 goto err; 561 if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx, 562 rsa->_method_mod_n)) 563 goto err; 564 } 565 566 if (blinding) 567 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 568 goto err; 569 570 j = bn_bn2binpad(ret, buf, num); 571 572 switch (padding) { 573 case RSA_PKCS1_PADDING: 574 r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num); 575 break; 576# ifndef OPENSSL_NO_SHA 577 case RSA_PKCS1_OAEP_PADDING: 578 r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0); 579 break; 580# endif 581 case RSA_SSLV23_PADDING: 582 r = RSA_padding_check_SSLv23(to, num, buf, j, num); 583 break; 584 case RSA_NO_PADDING: 585 memcpy(to, buf, (r = j)); 586 break; 587 default: 588 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE); 589 goto err; 590 } 591 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED); 592 err_clear_last_constant_time(r >= 0); 593 594 err: 595 if (ctx != NULL) { 596 BN_CTX_end(ctx); 597 BN_CTX_free(ctx); 598 } 599 if (buf != NULL) { 600 OPENSSL_cleanse(buf, num); 601 OPENSSL_free(buf); 602 } 603 return (r); 604} 605 606/* signature verification */ 607static int RSA_eay_public_decrypt(int flen, const unsigned char *from, 608 unsigned char *to, RSA *rsa, int padding) 609{ 610 BIGNUM *f, *ret; 611 int i, num = 0, r = -1; 612 unsigned char *buf = NULL; 613 BN_CTX *ctx = NULL; 614 615 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 616 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE); 617 return -1; 618 } 619 620 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 621 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 622 return -1; 623 } 624 625 /* for large moduli, enforce exponent limit */ 626 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 627 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 628 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 629 return -1; 630 } 631 } 632 633 if ((ctx = BN_CTX_new()) == NULL) 634 goto err; 635 BN_CTX_start(ctx); 636 f = BN_CTX_get(ctx); 637 ret = BN_CTX_get(ctx); 638 num = BN_num_bytes(rsa->n); 639 buf = OPENSSL_malloc(num); 640 if (!f || !ret || !buf) { 641 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE); 642 goto err; 643 } 644 645 /* 646 * This check was for equality but PGP does evil things and chops off the 647 * top '0' bytes 648 */ 649 if (flen > num) { 650 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_DATA_GREATER_THAN_MOD_LEN); 651 goto err; 652 } 653 654 if (BN_bin2bn(from, flen, f) == NULL) 655 goto err; 656 657 if (BN_ucmp(f, rsa->n) >= 0) { 658 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 659 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 660 goto err; 661 } 662 663 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 664 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, 665 rsa->n, ctx)) 666 goto err; 667 668 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 669 rsa->_method_mod_n)) 670 goto err; 671 672 if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12)) 673 if (!BN_sub(ret, rsa->n, ret)) 674 goto err; 675 676 i = bn_bn2binpad(ret, buf, num); 677 678 switch (padding) { 679 case RSA_PKCS1_PADDING: 680 r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num); 681 break; 682 case RSA_X931_PADDING: 683 r = RSA_padding_check_X931(to, num, buf, i, num); 684 break; 685 case RSA_NO_PADDING: 686 memcpy(to, buf, (r = i)); 687 break; 688 default: 689 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE); 690 goto err; 691 } 692 if (r < 0) 693 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_PADDING_CHECK_FAILED); 694 695 err: 696 if (ctx != NULL) { 697 BN_CTX_end(ctx); 698 BN_CTX_free(ctx); 699 } 700 if (buf != NULL) { 701 OPENSSL_cleanse(buf, num); 702 OPENSSL_free(buf); 703 } 704 return (r); 705} 706 707static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) 708{ 709 BIGNUM *r1, *m1, *vrfy; 710 BIGNUM local_dmp1, local_dmq1, local_c, local_r1; 711 BIGNUM *dmp1, *dmq1, *c, *pr1; 712 int ret = 0, smooth = 0; 713 714 BN_CTX_start(ctx); 715 r1 = BN_CTX_get(ctx); 716 m1 = BN_CTX_get(ctx); 717 vrfy = BN_CTX_get(ctx); 718 719 { 720 BIGNUM local_p, local_q; 721 BIGNUM *p = NULL, *q = NULL; 722 723 /* 724 * Make sure BN_mod_inverse in Montgomery intialization uses the 725 * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set) 726 */ 727 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 728 BN_init(&local_p); 729 p = &local_p; 730 BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME); 731 732 BN_init(&local_q); 733 q = &local_q; 734 BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME); 735 } else { 736 p = rsa->p; 737 q = rsa->q; 738 } 739 740 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { 741 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA, 742 p, ctx)) 743 goto err; 744 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA, 745 q, ctx)) 746 goto err; 747 748 smooth = (rsa->meth->bn_mod_exp == BN_mod_exp_mont) 749 && (BN_num_bits(q) == BN_num_bits(p)); 750 } 751 } 752 753 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 754 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, 755 rsa->n, ctx)) 756 goto err; 757 758 if (smooth) { 759 /* 760 * Conversion from Montgomery domain, a.k.a. Montgomery reduction, 761 * accepts values in [0-m*2^w) range. w is m's bit width rounded up 762 * to limb width. So that at the very least if |I| is fully reduced, 763 * i.e. less than p*q, we can count on from-to round to perform 764 * below modulo operations on |I|. Unlike BN_mod it's constant time. 765 */ 766 if (/* m1 = I moq q */ 767 !bn_from_mont_fixed_top(m1, I, rsa->_method_mod_q, ctx) 768 || !bn_to_mont_fixed_top(m1, m1, rsa->_method_mod_q, ctx) 769 /* m1 = m1^dmq1 mod q */ 770 || !BN_mod_exp_mont_consttime(m1, m1, rsa->dmq1, rsa->q, ctx, 771 rsa->_method_mod_q) 772 /* r1 = I mod p */ 773 || !bn_from_mont_fixed_top(r1, I, rsa->_method_mod_p, ctx) 774 || !bn_to_mont_fixed_top(r1, r1, rsa->_method_mod_p, ctx) 775 /* r1 = r1^dmp1 mod p */ 776 || !BN_mod_exp_mont_consttime(r1, r1, rsa->dmp1, rsa->p, ctx, 777 rsa->_method_mod_p) 778 /* r1 = (r1 - m1) mod p */ 779 /* 780 * bn_mod_sub_fixed_top is not regular modular subtraction, 781 * it can tolerate subtrahend to be larger than modulus, but 782 * not bit-wise wider. This makes up for uncommon q>p case, 783 * when |m1| can be larger than |rsa->p|. 784 */ 785 || !bn_mod_sub_fixed_top(r1, r1, m1, rsa->p) 786 787 /* r1 = r1 * iqmp mod p */ 788 || !bn_to_mont_fixed_top(r1, r1, rsa->_method_mod_p, ctx) 789 || !bn_mul_mont_fixed_top(r1, r1, rsa->iqmp, rsa->_method_mod_p, 790 ctx) 791 /* r0 = r1 * q + m1 */ 792 || !bn_mul_fixed_top(r0, r1, rsa->q, ctx) 793 || !bn_mod_add_fixed_top(r0, r0, m1, rsa->n)) 794 goto err; 795 796 goto tail; 797 } 798 799 /* compute I mod q */ 800 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 801 c = &local_c; 802 BN_with_flags(c, I, BN_FLG_CONSTTIME); 803 if (!BN_mod(r1, c, rsa->q, ctx)) 804 goto err; 805 } else { 806 if (!BN_mod(r1, I, rsa->q, ctx)) 807 goto err; 808 } 809 810 /* compute r1^dmq1 mod q */ 811 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 812 dmq1 = &local_dmq1; 813 BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME); 814 } else 815 dmq1 = rsa->dmq1; 816 if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q)) 817 goto err; 818 819 /* compute I mod p */ 820 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 821 c = &local_c; 822 BN_with_flags(c, I, BN_FLG_CONSTTIME); 823 if (!BN_mod(r1, c, rsa->p, ctx)) 824 goto err; 825 } else { 826 if (!BN_mod(r1, I, rsa->p, ctx)) 827 goto err; 828 } 829 830 /* compute r1^dmp1 mod p */ 831 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 832 dmp1 = &local_dmp1; 833 BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 834 } else 835 dmp1 = rsa->dmp1; 836 if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p)) 837 goto err; 838 839 if (!BN_sub(r0, r0, m1)) 840 goto err; 841 /* 842 * This will help stop the size of r0 increasing, which does affect the 843 * multiply if it optimised for a power of 2 size 844 */ 845 if (BN_is_negative(r0)) 846 if (!BN_add(r0, r0, rsa->p)) 847 goto err; 848 849 if (!BN_mul(r1, r0, rsa->iqmp, ctx)) 850 goto err; 851 852 /* Turn BN_FLG_CONSTTIME flag on before division operation */ 853 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 854 pr1 = &local_r1; 855 BN_with_flags(pr1, r1, BN_FLG_CONSTTIME); 856 } else 857 pr1 = r1; 858 if (!BN_mod(r0, pr1, rsa->p, ctx)) 859 goto err; 860 861 /* 862 * If p < q it is occasionally possible for the correction of adding 'p' 863 * if r0 is negative above to leave the result still negative. This can 864 * break the private key operations: the following second correction 865 * should *always* correct this rare occurrence. This will *never* happen 866 * with OpenSSL generated keys because they ensure p > q [steve] 867 */ 868 if (BN_is_negative(r0)) 869 if (!BN_add(r0, r0, rsa->p)) 870 goto err; 871 if (!BN_mul(r1, r0, rsa->q, ctx)) 872 goto err; 873 if (!BN_add(r0, r1, m1)) 874 goto err; 875 876 tail: 877 if (rsa->e && rsa->n) { 878 if (rsa->meth->bn_mod_exp == BN_mod_exp_mont) { 879 if (!BN_mod_exp_mont(vrfy, r0, rsa->e, rsa->n, ctx, 880 rsa->_method_mod_n)) 881 goto err; 882 } else { 883 bn_correct_top(r0); 884 if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx, 885 rsa->_method_mod_n)) 886 goto err; 887 } 888 /* 889 * If 'I' was greater than (or equal to) rsa->n, the operation will 890 * be equivalent to using 'I mod n'. However, the result of the 891 * verify will *always* be less than 'n' so we don't check for 892 * absolute equality, just congruency. 893 */ 894 if (!BN_sub(vrfy, vrfy, I)) 895 goto err; 896 if (BN_is_zero(vrfy)) { 897 bn_correct_top(r0); 898 ret = 1; 899 goto err; /* not actually error */ 900 } 901 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) 902 goto err; 903 if (BN_is_negative(vrfy)) 904 if (!BN_add(vrfy, vrfy, rsa->n)) 905 goto err; 906 if (!BN_is_zero(vrfy)) { 907 /* 908 * 'I' and 'vrfy' aren't congruent mod n. Don't leak 909 * miscalculated CRT output, just do a raw (slower) mod_exp and 910 * return that instead. 911 */ 912 913 BIGNUM local_d; 914 BIGNUM *d = NULL; 915 916 if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) { 917 d = &local_d; 918 BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME); 919 } else 920 d = rsa->d; 921 if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx, 922 rsa->_method_mod_n)) 923 goto err; 924 } 925 } 926 /* 927 * It's unfortunate that we have to bn_correct_top(r0). What hopefully 928 * saves the day is that correction is highly unlike, and private key 929 * operations are customarily performed on blinded message. Which means 930 * that attacker won't observe correlation with chosen plaintext. 931 * Secondly, remaining code would still handle it in same computational 932 * time and even conceal memory access pattern around corrected top. 933 */ 934 bn_correct_top(r0); 935 ret = 1; 936 err: 937 BN_CTX_end(ctx); 938 return (ret); 939} 940 941static int RSA_eay_init(RSA *rsa) 942{ 943 rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE; 944 return (1); 945} 946 947static int RSA_eay_finish(RSA *rsa) 948{ 949 if (rsa->_method_mod_n != NULL) 950 BN_MONT_CTX_free(rsa->_method_mod_n); 951 if (rsa->_method_mod_p != NULL) 952 BN_MONT_CTX_free(rsa->_method_mod_p); 953 if (rsa->_method_mod_q != NULL) 954 BN_MONT_CTX_free(rsa->_method_mod_q); 955 return (1); 956} 957 958#endif 959