1 /* $OpenBSD: rsa_eay.c,v 1.42 2016/07/07 11:53:12 bcook 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 static int RSA_eay_public_encrypt(int flen, const unsigned char *from, 122 unsigned char *to, RSA *rsa, int padding); 123 static int RSA_eay_private_encrypt(int flen, const unsigned char *from, 124 unsigned char *to, RSA *rsa, int padding); 125 static int RSA_eay_public_decrypt(int flen, const unsigned char *from, 126 unsigned char *to, RSA *rsa, int padding); 127 static int RSA_eay_private_decrypt(int flen, const unsigned char *from, 128 unsigned char *to, RSA *rsa, int padding); 129 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx); 130 static int RSA_eay_init(RSA *rsa); 131 static int RSA_eay_finish(RSA *rsa); 132 133 static RSA_METHOD rsa_pkcs1_eay_meth = { 134 .name = "Eric Young's PKCS#1 RSA", 135 .rsa_pub_enc = RSA_eay_public_encrypt, 136 .rsa_pub_dec = RSA_eay_public_decrypt, /* signature verification */ 137 .rsa_priv_enc = RSA_eay_private_encrypt, /* signing */ 138 .rsa_priv_dec = RSA_eay_private_decrypt, 139 .rsa_mod_exp = RSA_eay_mod_exp, 140 .bn_mod_exp = BN_mod_exp_mont, /* XXX probably we should not use Montgomery if e == 3 */ 141 .init = RSA_eay_init, 142 .finish = RSA_eay_finish, 143 }; 144 145 const RSA_METHOD * 146 RSA_PKCS1_SSLeay(void) 147 { 148 return &rsa_pkcs1_eay_meth; 149 } 150 151 static int 152 RSA_eay_public_encrypt(int flen, const unsigned char *from, unsigned char *to, 153 RSA *rsa, int padding) 154 { 155 BIGNUM *f, *ret; 156 int i, j, k, num = 0, r = -1; 157 unsigned char *buf = NULL; 158 BN_CTX *ctx = NULL; 159 160 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 161 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE); 162 return -1; 163 } 164 165 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 166 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 167 return -1; 168 } 169 170 /* for large moduli, enforce exponent limit */ 171 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 172 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 173 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE); 174 return -1; 175 } 176 } 177 178 if ((ctx = BN_CTX_new()) == NULL) 179 goto err; 180 181 BN_CTX_start(ctx); 182 f = BN_CTX_get(ctx); 183 ret = BN_CTX_get(ctx); 184 num = BN_num_bytes(rsa->n); 185 buf = malloc(num); 186 187 if (f == NULL || ret == NULL || buf == NULL) { 188 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE); 189 goto err; 190 } 191 192 switch (padding) { 193 case RSA_PKCS1_PADDING: 194 i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen); 195 break; 196 #ifndef OPENSSL_NO_SHA 197 case RSA_PKCS1_OAEP_PADDING: 198 i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0); 199 break; 200 #endif 201 case RSA_SSLV23_PADDING: 202 i = RSA_padding_add_SSLv23(buf, num, from, flen); 203 break; 204 case RSA_NO_PADDING: 205 i = RSA_padding_add_none(buf, num, from, flen); 206 break; 207 default: 208 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, 209 RSA_R_UNKNOWN_PADDING_TYPE); 210 goto err; 211 } 212 if (i <= 0) 213 goto err; 214 215 if (BN_bin2bn(buf, num, f) == NULL) 216 goto err; 217 218 if (BN_ucmp(f, rsa->n) >= 0) { 219 /* usually the padding functions would catch this */ 220 RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, 221 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 222 goto err; 223 } 224 225 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 226 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 227 CRYPTO_LOCK_RSA, rsa->n, ctx)) 228 goto err; 229 230 if (!rsa->meth->bn_mod_exp(ret, f,rsa->e, rsa->n, ctx, 231 rsa->_method_mod_n)) 232 goto err; 233 234 /* put in leading 0 bytes if the number is less than the 235 * length of the modulus */ 236 j = BN_num_bytes(ret); 237 i = BN_bn2bin(ret, &(to[num - j])); 238 for (k = 0; k < num - i; k++) 239 to[k] = 0; 240 241 r = num; 242 err: 243 if (ctx != NULL) { 244 BN_CTX_end(ctx); 245 BN_CTX_free(ctx); 246 } 247 if (buf != NULL) { 248 explicit_bzero(buf, num); 249 free(buf); 250 } 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 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 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 case RSA_SSLV23_PADDING: 390 default: 391 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 392 RSA_R_UNKNOWN_PADDING_TYPE); 393 goto err; 394 } 395 if (i <= 0) 396 goto err; 397 398 if (BN_bin2bn(buf, num, f) == NULL) 399 goto err; 400 401 if (BN_ucmp(f, rsa->n) >= 0) { 402 /* usually the padding functions would catch this */ 403 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 404 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 405 goto err; 406 } 407 408 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 409 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 410 if (blinding == NULL) { 411 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 412 ERR_R_INTERNAL_ERROR); 413 goto err; 414 } 415 } 416 417 if (blinding != NULL) { 418 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 419 RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, 420 ERR_R_MALLOC_FAILURE); 421 goto err; 422 } 423 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 424 goto err; 425 } 426 427 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 428 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 429 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 430 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 431 goto err; 432 } else { 433 BIGNUM d; 434 435 BN_init(&d); 436 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 437 438 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 439 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 440 CRYPTO_LOCK_RSA, rsa->n, ctx)) 441 goto err; 442 443 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 444 rsa->_method_mod_n)) { 445 goto err; 446 } 447 } 448 449 if (blinding) 450 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 451 goto err; 452 453 if (padding == RSA_X931_PADDING) { 454 BN_sub(f, rsa->n, ret); 455 if (BN_cmp(ret, f) > 0) 456 res = f; 457 else 458 res = ret; 459 } else 460 res = ret; 461 462 /* put in leading 0 bytes if the number is less than the 463 * length of the modulus */ 464 j = BN_num_bytes(res); 465 i = BN_bn2bin(res, &(to[num - j])); 466 for (k = 0; k < num - i; k++) 467 to[k] = 0; 468 469 r = num; 470 err: 471 if (ctx != NULL) { 472 BN_CTX_end(ctx); 473 BN_CTX_free(ctx); 474 } 475 if (buf != NULL) { 476 explicit_bzero(buf, num); 477 free(buf); 478 } 479 return r; 480 } 481 482 static int 483 RSA_eay_private_decrypt(int flen, const unsigned char *from, unsigned char *to, 484 RSA *rsa, int padding) 485 { 486 BIGNUM *f, *ret; 487 int j, num = 0, r = -1; 488 unsigned char *p; 489 unsigned char *buf = NULL; 490 BN_CTX *ctx = NULL; 491 int local_blinding = 0; 492 /* 493 * Used only if the blinding structure is shared. A non-NULL unblind 494 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 495 * the unblinding factor outside the blinding structure. 496 */ 497 BIGNUM *unblind = NULL; 498 BN_BLINDING *blinding = NULL; 499 500 if ((ctx = BN_CTX_new()) == NULL) 501 goto err; 502 503 BN_CTX_start(ctx); 504 f = BN_CTX_get(ctx); 505 ret = BN_CTX_get(ctx); 506 num = BN_num_bytes(rsa->n); 507 buf = malloc(num); 508 509 if (!f || !ret || !buf) { 510 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE); 511 goto err; 512 } 513 514 /* This check was for equality but PGP does evil things 515 * and chops off the top '0' bytes */ 516 if (flen > num) { 517 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 518 RSA_R_DATA_GREATER_THAN_MOD_LEN); 519 goto err; 520 } 521 522 /* make data into a big number */ 523 if (BN_bin2bn(from, (int)flen, f) == NULL) 524 goto err; 525 526 if (BN_ucmp(f, rsa->n) >= 0) { 527 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 528 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 529 goto err; 530 } 531 532 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 533 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 534 if (blinding == NULL) { 535 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 536 ERR_R_INTERNAL_ERROR); 537 goto err; 538 } 539 } 540 541 if (blinding != NULL) { 542 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 543 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 544 ERR_R_MALLOC_FAILURE); 545 goto err; 546 } 547 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 548 goto err; 549 } 550 551 /* do the decrypt */ 552 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 553 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 554 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 555 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 556 goto err; 557 } else { 558 BIGNUM d; 559 560 BN_init(&d); 561 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 562 563 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 564 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 565 CRYPTO_LOCK_RSA, rsa->n, ctx)) 566 goto err; 567 568 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 569 rsa->_method_mod_n)) { 570 goto err; 571 } 572 } 573 574 if (blinding) 575 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 576 goto err; 577 578 p = buf; 579 j = BN_bn2bin(ret, p); /* j is only used with no-padding mode */ 580 581 switch (padding) { 582 case RSA_PKCS1_PADDING: 583 r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num); 584 break; 585 #ifndef OPENSSL_NO_SHA 586 case RSA_PKCS1_OAEP_PADDING: 587 r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0); 588 break; 589 #endif 590 case RSA_SSLV23_PADDING: 591 r = RSA_padding_check_SSLv23(to, num, buf, j, num); 592 break; 593 case RSA_NO_PADDING: 594 r = RSA_padding_check_none(to, num, buf, j, num); 595 break; 596 default: 597 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 598 RSA_R_UNKNOWN_PADDING_TYPE); 599 goto err; 600 } 601 if (r < 0) 602 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 603 RSA_R_PADDING_CHECK_FAILED); 604 605 err: 606 if (ctx != NULL) { 607 BN_CTX_end(ctx); 608 BN_CTX_free(ctx); 609 } 610 if (buf != NULL) { 611 explicit_bzero(buf, num); 612 free(buf); 613 } 614 return r; 615 } 616 617 /* signature verification */ 618 static int 619 RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to, 620 RSA *rsa, int padding) 621 { 622 BIGNUM *f, *ret; 623 int i, num = 0, r = -1; 624 unsigned char *p; 625 unsigned char *buf = NULL; 626 BN_CTX *ctx = NULL; 627 628 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 629 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE); 630 return -1; 631 } 632 633 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 634 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 635 return -1; 636 } 637 638 /* for large moduli, enforce exponent limit */ 639 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 640 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 641 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 642 return -1; 643 } 644 } 645 646 if ((ctx = BN_CTX_new()) == NULL) 647 goto err; 648 649 BN_CTX_start(ctx); 650 f = BN_CTX_get(ctx); 651 ret = BN_CTX_get(ctx); 652 num = BN_num_bytes(rsa->n); 653 buf = malloc(num); 654 655 if (!f || !ret || !buf) { 656 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE); 657 goto err; 658 } 659 660 /* This check was for equality but PGP does evil things 661 * and chops off the top '0' bytes */ 662 if (flen > num) { 663 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 664 RSA_R_DATA_GREATER_THAN_MOD_LEN); 665 goto err; 666 } 667 668 if (BN_bin2bn(from, flen, f) == NULL) 669 goto err; 670 671 if (BN_ucmp(f, rsa->n) >= 0) { 672 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 673 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 674 goto err; 675 } 676 677 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 678 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 679 CRYPTO_LOCK_RSA, rsa->n, ctx)) 680 goto err; 681 682 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 683 rsa->_method_mod_n)) 684 goto err; 685 686 if (padding == RSA_X931_PADDING && (ret->d[0] & 0xf) != 12) 687 if (!BN_sub(ret, rsa->n, ret)) 688 goto err; 689 690 p = buf; 691 i = BN_bn2bin(ret, p); 692 693 switch (padding) { 694 case RSA_PKCS1_PADDING: 695 r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num); 696 break; 697 case RSA_X931_PADDING: 698 r = RSA_padding_check_X931(to, num, buf, i, num); 699 break; 700 case RSA_NO_PADDING: 701 r = RSA_padding_check_none(to, num, buf, i, num); 702 break; 703 default: 704 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 705 RSA_R_UNKNOWN_PADDING_TYPE); 706 goto err; 707 } 708 if (r < 0) 709 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 710 RSA_R_PADDING_CHECK_FAILED); 711 712 err: 713 if (ctx != NULL) { 714 BN_CTX_end(ctx); 715 BN_CTX_free(ctx); 716 } 717 if (buf != NULL) { 718 explicit_bzero(buf, num); 719 free(buf); 720 } 721 return r; 722 } 723 724 static int 725 RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) 726 { 727 BIGNUM *r1, *m1, *vrfy; 728 BIGNUM dmp1, dmq1, c, pr1; 729 int ret = 0; 730 731 BN_CTX_start(ctx); 732 r1 = BN_CTX_get(ctx); 733 m1 = BN_CTX_get(ctx); 734 vrfy = BN_CTX_get(ctx); 735 if (r1 == NULL || m1 == NULL || vrfy == NULL) { 736 RSAerr(RSA_F_RSA_EAY_MOD_EXP, ERR_R_MALLOC_FAILURE); 737 goto err; 738 } 739 740 { 741 BIGNUM p, q; 742 743 /* 744 * Make sure BN_mod_inverse in Montgomery intialization uses the 745 * BN_FLG_CONSTTIME flag 746 */ 747 BN_init(&p); 748 BN_init(&q); 749 BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME); 750 BN_with_flags(&q, rsa->q, BN_FLG_CONSTTIME); 751 752 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { 753 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, 754 CRYPTO_LOCK_RSA, &p, ctx) || 755 !BN_MONT_CTX_set_locked(&rsa->_method_mod_q, 756 CRYPTO_LOCK_RSA, &q, ctx)) { 757 goto err; 758 } 759 } 760 } 761 762 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 763 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 764 CRYPTO_LOCK_RSA, rsa->n, ctx)) 765 goto err; 766 767 /* compute I mod q */ 768 BN_init(&c); 769 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 770 771 if (!BN_mod(r1, &c, rsa->q, ctx)) 772 goto err; 773 774 /* compute r1^dmq1 mod q */ 775 BN_init(&dmq1); 776 BN_with_flags(&dmq1, rsa->dmq1, BN_FLG_CONSTTIME); 777 778 if (!rsa->meth->bn_mod_exp(m1, r1, &dmq1, rsa->q, ctx, 779 rsa->_method_mod_q)) 780 goto err; 781 782 /* compute I mod p */ 783 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 784 785 if (!BN_mod(r1, &c, rsa->p, ctx)) 786 goto err; 787 788 /* compute r1^dmp1 mod p */ 789 BN_init(&dmp1); 790 BN_with_flags(&dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 791 792 if (!rsa->meth->bn_mod_exp(r0, r1, &dmp1, rsa->p, ctx, 793 rsa->_method_mod_p)) 794 goto err; 795 796 if (!BN_sub(r0, r0, m1)) 797 goto err; 798 799 /* 800 * This will help stop the size of r0 increasing, which does 801 * affect the multiply if it optimised for a power of 2 size 802 */ 803 if (BN_is_negative(r0)) 804 if (!BN_add(r0, r0, rsa->p)) 805 goto err; 806 807 if (!BN_mul(r1, r0, rsa->iqmp, ctx)) 808 goto err; 809 810 /* Turn BN_FLG_CONSTTIME flag on before division operation */ 811 BN_init(&pr1); 812 BN_with_flags(&pr1, r1, BN_FLG_CONSTTIME); 813 814 if (!BN_mod(r0, &pr1, rsa->p, ctx)) 815 goto err; 816 817 /* 818 * If p < q it is occasionally possible for the correction of 819 * adding 'p' if r0 is negative above to leave the result still 820 * negative. This can break the private key operations: the following 821 * second correction should *always* correct this rare occurrence. 822 * This will *never* happen with OpenSSL generated keys because 823 * they ensure p > q [steve] 824 */ 825 if (BN_is_negative(r0)) 826 if (!BN_add(r0, r0, rsa->p)) 827 goto err; 828 if (!BN_mul(r1, r0, rsa->q, ctx)) 829 goto err; 830 if (!BN_add(r0, r1, m1)) 831 goto err; 832 833 if (rsa->e && rsa->n) { 834 if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx, 835 rsa->_method_mod_n)) 836 goto err; 837 /* 838 * If 'I' was greater than (or equal to) rsa->n, the operation 839 * will be equivalent to using 'I mod n'. However, the result of 840 * the verify will *always* be less than 'n' so we don't check 841 * for absolute equality, just congruency. 842 */ 843 if (!BN_sub(vrfy, vrfy, I)) 844 goto err; 845 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) 846 goto err; 847 if (BN_is_negative(vrfy)) 848 if (!BN_add(vrfy, vrfy, rsa->n)) 849 goto err; 850 if (!BN_is_zero(vrfy)) { 851 /* 852 * 'I' and 'vrfy' aren't congruent mod n. Don't leak 853 * miscalculated CRT output, just do a raw (slower) 854 * mod_exp and return that instead. 855 */ 856 BIGNUM d; 857 858 BN_init(&d); 859 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 860 861 if (!rsa->meth->bn_mod_exp(r0, I, &d, rsa->n, ctx, 862 rsa->_method_mod_n)) { 863 goto err; 864 } 865 } 866 } 867 ret = 1; 868 err: 869 BN_CTX_end(ctx); 870 return ret; 871 } 872 873 static int 874 RSA_eay_init(RSA *rsa) 875 { 876 rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE; 877 return 1; 878 } 879 880 static int 881 RSA_eay_finish(RSA *rsa) 882 { 883 BN_MONT_CTX_free(rsa->_method_mod_n); 884 BN_MONT_CTX_free(rsa->_method_mod_p); 885 BN_MONT_CTX_free(rsa->_method_mod_q); 886 887 return 1; 888 } 889