1 /* $OpenBSD: rsa_eay.c,v 1.44 2017/01/21 09:38:59 beck 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_SSLeay(void) 149 { 150 return &rsa_pkcs1_eay_meth; 151 } 152 153 static int 154 RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *to, 155 RSA *rsa, int padding) 156 { 157 BIGNUM *f, *ret; 158 int i, j, k, num = 0, r = -1; 159 unsigned char *buf = NULL; 160 BN_CTX *ctx = NULL; 161 162 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 163 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE); 164 return -1; 165 } 166 167 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 168 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 169 return -1; 170 } 171 172 /* for large moduli, enforce exponent limit */ 173 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 174 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 175 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 176 return -1; 177 } 178 } 179 180 if ((ctx = BN_CTX_new()) == NULL) 181 goto err; 182 183 BN_CTX_start(ctx); 184 f = BN_CTX_get(ctx); 185 ret = BN_CTX_get(ctx); 186 num = BN_num_bytes(rsa->n); 187 buf = malloc(num); 188 189 if (f == NULL || ret == NULL || buf == NULL) { 190 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE); 191 goto err; 192 } 193 194 switch (padding) { 195 case RSA_PKCS1_PADDING: 196 i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen); 197 break; 198 #ifndef OPENSSL_NO_SHA 199 case RSA_PKCS1_OAEP_PADDING: 200 i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0); 201 break; 202 #endif 203 case RSA_SSLV23_PADDING: 204 i = RSA_padding_add_SSLv23(buf, num, from, flen); 205 break; 206 case RSA_NO_PADDING: 207 i = RSA_padding_add_none(buf, num, from, flen); 208 break; 209 default: 210 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, 211 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, 229 CRYPTO_LOCK_RSA, 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 /* put in leading 0 bytes if the number is less than the 237 * length of the modulus */ 238 j = BN_num_bytes(ret); 239 i = BN_bn2bin(ret, &(to[num - j])); 240 for (k = 0; k < num - i; k++) 241 to[k] = 0; 242 243 r = num; 244 err: 245 if (ctx != NULL) { 246 BN_CTX_end(ctx); 247 BN_CTX_free(ctx); 248 } 249 if (buf != NULL) { 250 explicit_bzero(buf, num); 251 free(buf); 252 } 253 return r; 254 } 255 256 static BN_BLINDING * 257 rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx) 258 { 259 BN_BLINDING *ret; 260 int got_write_lock = 0; 261 CRYPTO_THREADID cur; 262 263 CRYPTO_r_lock(CRYPTO_LOCK_RSA); 264 265 if (rsa->blinding == NULL) { 266 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 267 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 268 got_write_lock = 1; 269 270 if (rsa->blinding == NULL) 271 rsa->blinding = RSA_setup_blinding(rsa, ctx); 272 } 273 274 ret = rsa->blinding; 275 if (ret == NULL) 276 goto err; 277 278 CRYPTO_THREADID_current(&cur); 279 if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) { 280 /* rsa->blinding is ours! */ 281 *local = 1; 282 } else { 283 /* resort to rsa->mt_blinding instead */ 284 /* 285 * Instruct rsa_blinding_convert(), rsa_blinding_invert() 286 * that the BN_BLINDING is shared, meaning that accesses 287 * require locks, and that the blinding factor must be 288 * stored outside the BN_BLINDING 289 */ 290 *local = 0; 291 292 if (rsa->mt_blinding == NULL) { 293 if (!got_write_lock) { 294 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 295 CRYPTO_w_lock(CRYPTO_LOCK_RSA); 296 got_write_lock = 1; 297 } 298 299 if (rsa->mt_blinding == NULL) 300 rsa->mt_blinding = RSA_setup_blinding(rsa, ctx); 301 } 302 ret = rsa->mt_blinding; 303 } 304 305 err: 306 if (got_write_lock) 307 CRYPTO_w_unlock(CRYPTO_LOCK_RSA); 308 else 309 CRYPTO_r_unlock(CRYPTO_LOCK_RSA); 310 return ret; 311 } 312 313 static int 314 rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) 315 { 316 if (unblind == NULL) 317 /* 318 * Local blinding: store the unblinding factor 319 * in BN_BLINDING. 320 */ 321 return BN_BLINDING_convert_ex(f, NULL, b, ctx); 322 else { 323 /* 324 * Shared blinding: store the unblinding factor 325 * outside BN_BLINDING. 326 */ 327 int ret; 328 CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING); 329 ret = BN_BLINDING_convert_ex(f, unblind, b, ctx); 330 CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING); 331 return ret; 332 } 333 } 334 335 static int 336 rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind, BN_CTX *ctx) 337 { 338 /* 339 * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex 340 * will use the unblinding factor stored in BN_BLINDING. 341 * If BN_BLINDING is shared between threads, unblind must be non-null: 342 * BN_BLINDING_invert_ex will then use the local unblinding factor, 343 * and will only read the modulus from BN_BLINDING. 344 * In both cases it's safe to access the blinding without a lock. 345 */ 346 return BN_BLINDING_invert_ex(f, unblind, b, ctx); 347 } 348 349 /* signing */ 350 static int 351 RSA_eay_private_encrypt(int flen, const unsigned char *from, unsigned char *to, 352 RSA *rsa, int padding) 353 { 354 BIGNUM *f, *ret, *res; 355 int i, j, k, num = 0, r = -1; 356 unsigned char *buf = NULL; 357 BN_CTX *ctx = NULL; 358 int local_blinding = 0; 359 /* 360 * Used only if the blinding structure is shared. A non-NULL unblind 361 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 362 * the unblinding factor outside the blinding structure. 363 */ 364 BIGNUM *unblind = NULL; 365 BN_BLINDING *blinding = NULL; 366 367 if ((ctx = BN_CTX_new()) == NULL) 368 goto err; 369 370 BN_CTX_start(ctx); 371 f = BN_CTX_get(ctx); 372 ret = BN_CTX_get(ctx); 373 num = BN_num_bytes(rsa->n); 374 buf = malloc(num); 375 376 if (f == NULL || ret == NULL || buf == NULL) { 377 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE); 378 goto err; 379 } 380 381 switch (padding) { 382 case RSA_PKCS1_PADDING: 383 i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen); 384 break; 385 case RSA_X931_PADDING: 386 i = RSA_padding_add_X931(buf, num, from, flen); 387 break; 388 case RSA_NO_PADDING: 389 i = RSA_padding_add_none(buf, num, from, flen); 390 break; 391 case RSA_SSLV23_PADDING: 392 default: 393 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 394 RSA_R_UNKNOWN_PADDING_TYPE); 395 goto err; 396 } 397 if (i <= 0) 398 goto err; 399 400 if (BN_bin2bn(buf, num, f) == NULL) 401 goto err; 402 403 if (BN_ucmp(f, rsa->n) >= 0) { 404 /* usually the padding functions would catch this */ 405 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 406 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 407 goto err; 408 } 409 410 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 411 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 412 if (blinding == NULL) { 413 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 414 ERR_R_INTERNAL_ERROR); 415 goto err; 416 } 417 } 418 419 if (blinding != NULL) { 420 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 421 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 422 ERR_R_MALLOC_FAILURE); 423 goto err; 424 } 425 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 426 goto err; 427 } 428 429 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 430 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 431 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 432 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 433 goto err; 434 } else { 435 BIGNUM d; 436 437 BN_init(&d); 438 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 439 440 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 441 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 442 CRYPTO_LOCK_RSA, rsa->n, ctx)) 443 goto err; 444 445 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 446 rsa->_method_mod_n)) { 447 goto err; 448 } 449 } 450 451 if (blinding) 452 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 453 goto err; 454 455 if (padding == RSA_X931_PADDING) { 456 BN_sub(f, rsa->n, ret); 457 if (BN_cmp(ret, f) > 0) 458 res = f; 459 else 460 res = ret; 461 } else 462 res = ret; 463 464 /* put in leading 0 bytes if the number is less than the 465 * length of the modulus */ 466 j = BN_num_bytes(res); 467 i = BN_bn2bin(res, &(to[num - j])); 468 for (k = 0; k < num - i; k++) 469 to[k] = 0; 470 471 r = num; 472 err: 473 if (ctx != NULL) { 474 BN_CTX_end(ctx); 475 BN_CTX_free(ctx); 476 } 477 if (buf != NULL) { 478 explicit_bzero(buf, num); 479 free(buf); 480 } 481 return r; 482 } 483 484 static int 485 RSA_eay_private_decrypt(int flen, const unsigned char *from, unsigned char *to, 486 RSA *rsa, int padding) 487 { 488 BIGNUM *f, *ret; 489 int j, num = 0, r = -1; 490 unsigned char *p; 491 unsigned char *buf = NULL; 492 BN_CTX *ctx = NULL; 493 int local_blinding = 0; 494 /* 495 * Used only if the blinding structure is shared. A non-NULL unblind 496 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 497 * the unblinding factor outside the blinding structure. 498 */ 499 BIGNUM *unblind = NULL; 500 BN_BLINDING *blinding = NULL; 501 502 if ((ctx = BN_CTX_new()) == NULL) 503 goto err; 504 505 BN_CTX_start(ctx); 506 f = BN_CTX_get(ctx); 507 ret = BN_CTX_get(ctx); 508 num = BN_num_bytes(rsa->n); 509 buf = malloc(num); 510 511 if (!f || !ret || !buf) { 512 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE); 513 goto err; 514 } 515 516 /* This check was for equality but PGP does evil things 517 * and chops off the top '0' bytes */ 518 if (flen > num) { 519 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 520 RSA_R_DATA_GREATER_THAN_MOD_LEN); 521 goto err; 522 } 523 524 /* make data into a big number */ 525 if (BN_bin2bn(from, (int)flen, f) == NULL) 526 goto err; 527 528 if (BN_ucmp(f, rsa->n) >= 0) { 529 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 530 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 531 goto err; 532 } 533 534 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 535 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 536 if (blinding == NULL) { 537 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 538 ERR_R_INTERNAL_ERROR); 539 goto err; 540 } 541 } 542 543 if (blinding != NULL) { 544 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 545 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 546 ERR_R_MALLOC_FAILURE); 547 goto err; 548 } 549 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 550 goto err; 551 } 552 553 /* do the decrypt */ 554 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 555 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 556 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 557 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 558 goto err; 559 } else { 560 BIGNUM d; 561 562 BN_init(&d); 563 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 564 565 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 566 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 567 CRYPTO_LOCK_RSA, rsa->n, ctx)) 568 goto err; 569 570 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 571 rsa->_method_mod_n)) { 572 goto err; 573 } 574 } 575 576 if (blinding) 577 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 578 goto err; 579 580 p = buf; 581 j = BN_bn2bin(ret, p); /* j is only used with no-padding mode */ 582 583 switch (padding) { 584 case RSA_PKCS1_PADDING: 585 r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num); 586 break; 587 #ifndef OPENSSL_NO_SHA 588 case RSA_PKCS1_OAEP_PADDING: 589 r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0); 590 break; 591 #endif 592 case RSA_SSLV23_PADDING: 593 r = RSA_padding_check_SSLv23(to, num, buf, j, num); 594 break; 595 case RSA_NO_PADDING: 596 r = RSA_padding_check_none(to, num, buf, j, num); 597 break; 598 default: 599 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 600 RSA_R_UNKNOWN_PADDING_TYPE); 601 goto err; 602 } 603 if (r < 0) 604 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 605 RSA_R_PADDING_CHECK_FAILED); 606 607 err: 608 if (ctx != NULL) { 609 BN_CTX_end(ctx); 610 BN_CTX_free(ctx); 611 } 612 if (buf != NULL) { 613 explicit_bzero(buf, num); 614 free(buf); 615 } 616 return r; 617 } 618 619 /* signature verification */ 620 static int 621 RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to, 622 RSA *rsa, int padding) 623 { 624 BIGNUM *f, *ret; 625 int i, num = 0, r = -1; 626 unsigned char *p; 627 unsigned char *buf = NULL; 628 BN_CTX *ctx = NULL; 629 630 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 631 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE); 632 return -1; 633 } 634 635 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 636 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 637 return -1; 638 } 639 640 /* for large moduli, enforce exponent limit */ 641 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 642 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 643 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 644 return -1; 645 } 646 } 647 648 if ((ctx = BN_CTX_new()) == NULL) 649 goto err; 650 651 BN_CTX_start(ctx); 652 f = BN_CTX_get(ctx); 653 ret = BN_CTX_get(ctx); 654 num = BN_num_bytes(rsa->n); 655 buf = malloc(num); 656 657 if (!f || !ret || !buf) { 658 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE); 659 goto err; 660 } 661 662 /* This check was for equality but PGP does evil things 663 * and chops off the top '0' bytes */ 664 if (flen > num) { 665 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 666 RSA_R_DATA_GREATER_THAN_MOD_LEN); 667 goto err; 668 } 669 670 if (BN_bin2bn(from, flen, f) == NULL) 671 goto err; 672 673 if (BN_ucmp(f, rsa->n) >= 0) { 674 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 675 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 676 goto err; 677 } 678 679 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 680 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 681 CRYPTO_LOCK_RSA, rsa->n, ctx)) 682 goto err; 683 684 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 685 rsa->_method_mod_n)) 686 goto err; 687 688 if (padding == RSA_X931_PADDING && (ret->d[0] & 0xf) != 12) 689 if (!BN_sub(ret, rsa->n, ret)) 690 goto err; 691 692 p = buf; 693 i = BN_bn2bin(ret, p); 694 695 switch (padding) { 696 case RSA_PKCS1_PADDING: 697 r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num); 698 break; 699 case RSA_X931_PADDING: 700 r = RSA_padding_check_X931(to, num, buf, i, num); 701 break; 702 case RSA_NO_PADDING: 703 r = RSA_padding_check_none(to, num, buf, i, num); 704 break; 705 default: 706 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 707 RSA_R_UNKNOWN_PADDING_TYPE); 708 goto err; 709 } 710 if (r < 0) 711 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 712 RSA_R_PADDING_CHECK_FAILED); 713 714 err: 715 if (ctx != NULL) { 716 BN_CTX_end(ctx); 717 BN_CTX_free(ctx); 718 } 719 if (buf != NULL) { 720 explicit_bzero(buf, num); 721 free(buf); 722 } 723 return r; 724 } 725 726 static int 727 RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) 728 { 729 BIGNUM *r1, *m1, *vrfy; 730 BIGNUM dmp1, dmq1, c, pr1; 731 int ret = 0; 732 733 BN_CTX_start(ctx); 734 r1 = BN_CTX_get(ctx); 735 m1 = BN_CTX_get(ctx); 736 vrfy = BN_CTX_get(ctx); 737 if (r1 == NULL || m1 == NULL || vrfy == NULL) { 738 RSAerr(RSA_F_RSA_EAY_MOD_EXP, ERR_R_MALLOC_FAILURE); 739 goto err; 740 } 741 742 { 743 BIGNUM p, q; 744 745 /* 746 * Make sure BN_mod_inverse in Montgomery intialization uses the 747 * BN_FLG_CONSTTIME flag 748 */ 749 BN_init(&p); 750 BN_init(&q); 751 BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME); 752 BN_with_flags(&q, rsa->q, BN_FLG_CONSTTIME); 753 754 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { 755 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, 756 CRYPTO_LOCK_RSA, &p, ctx) || 757 !BN_MONT_CTX_set_locked(&rsa->_method_mod_q, 758 CRYPTO_LOCK_RSA, &q, ctx)) { 759 goto err; 760 } 761 } 762 } 763 764 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 765 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 766 CRYPTO_LOCK_RSA, rsa->n, ctx)) 767 goto err; 768 769 /* compute I mod q */ 770 BN_init(&c); 771 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 772 773 if (!BN_mod(r1, &c, rsa->q, ctx)) 774 goto err; 775 776 /* compute r1^dmq1 mod q */ 777 BN_init(&dmq1); 778 BN_with_flags(&dmq1, rsa->dmq1, BN_FLG_CONSTTIME); 779 780 if (!rsa->meth->bn_mod_exp(m1, r1, &dmq1, rsa->q, ctx, 781 rsa->_method_mod_q)) 782 goto err; 783 784 /* compute I mod p */ 785 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 786 787 if (!BN_mod(r1, &c, rsa->p, ctx)) 788 goto err; 789 790 /* compute r1^dmp1 mod p */ 791 BN_init(&dmp1); 792 BN_with_flags(&dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 793 794 if (!rsa->meth->bn_mod_exp(r0, r1, &dmp1, rsa->p, ctx, 795 rsa->_method_mod_p)) 796 goto err; 797 798 if (!BN_sub(r0, r0, m1)) 799 goto err; 800 801 /* 802 * This will help stop the size of r0 increasing, which does 803 * affect the multiply if it optimised for a power of 2 size 804 */ 805 if (BN_is_negative(r0)) 806 if (!BN_add(r0, r0, rsa->p)) 807 goto err; 808 809 if (!BN_mul(r1, r0, rsa->iqmp, ctx)) 810 goto err; 811 812 /* Turn BN_FLG_CONSTTIME flag on before division operation */ 813 BN_init(&pr1); 814 BN_with_flags(&pr1, r1, BN_FLG_CONSTTIME); 815 816 if (!BN_mod(r0, &pr1, rsa->p, ctx)) 817 goto err; 818 819 /* 820 * If p < q it is occasionally possible for the correction of 821 * adding 'p' if r0 is negative above to leave the result still 822 * negative. This can break the private key operations: the following 823 * second correction should *always* correct this rare occurrence. 824 * This will *never* happen with OpenSSL generated keys because 825 * they ensure p > q [steve] 826 */ 827 if (BN_is_negative(r0)) 828 if (!BN_add(r0, r0, rsa->p)) 829 goto err; 830 if (!BN_mul(r1, r0, rsa->q, ctx)) 831 goto err; 832 if (!BN_add(r0, r1, m1)) 833 goto err; 834 835 if (rsa->e && rsa->n) { 836 if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx, 837 rsa->_method_mod_n)) 838 goto err; 839 /* 840 * If 'I' was greater than (or equal to) rsa->n, the operation 841 * will be equivalent to using 'I mod n'. However, the result of 842 * the verify will *always* be less than 'n' so we don't check 843 * for absolute equality, just congruency. 844 */ 845 if (!BN_sub(vrfy, vrfy, I)) 846 goto err; 847 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) 848 goto err; 849 if (BN_is_negative(vrfy)) 850 if (!BN_add(vrfy, vrfy, rsa->n)) 851 goto err; 852 if (!BN_is_zero(vrfy)) { 853 /* 854 * 'I' and 'vrfy' aren't congruent mod n. Don't leak 855 * miscalculated CRT output, just do a raw (slower) 856 * mod_exp and return that instead. 857 */ 858 BIGNUM d; 859 860 BN_init(&d); 861 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 862 863 if (!rsa->meth->bn_mod_exp(r0, I, &d, rsa->n, ctx, 864 rsa->_method_mod_n)) { 865 goto err; 866 } 867 } 868 } 869 ret = 1; 870 err: 871 BN_CTX_end(ctx); 872 return ret; 873 } 874 875 static int 876 RSA_eay_init(RSA *rsa) 877 { 878 rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE; 879 return 1; 880 } 881 882 static int 883 RSA_eay_finish(RSA *rsa) 884 { 885 BN_MONT_CTX_free(rsa->_method_mod_n); 886 BN_MONT_CTX_free(rsa->_method_mod_p); 887 BN_MONT_CTX_free(rsa->_method_mod_q); 888 889 return 1; 890 } 891