1 /* $OpenBSD: rsa_eay.c,v 1.41 2016/06/30 02:02:06 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_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 436 437 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 438 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 439 CRYPTO_LOCK_RSA, rsa->n, ctx)) 440 goto err; 441 442 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 443 rsa->_method_mod_n)) { 444 goto err; 445 } 446 } 447 448 if (blinding) 449 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 450 goto err; 451 452 if (padding == RSA_X931_PADDING) { 453 BN_sub(f, rsa->n, ret); 454 if (BN_cmp(ret, f) > 0) 455 res = f; 456 else 457 res = ret; 458 } else 459 res = ret; 460 461 /* put in leading 0 bytes if the number is less than the 462 * length of the modulus */ 463 j = BN_num_bytes(res); 464 i = BN_bn2bin(res, &(to[num - j])); 465 for (k = 0; k < num - i; k++) 466 to[k] = 0; 467 468 r = num; 469 err: 470 if (ctx != NULL) { 471 BN_CTX_end(ctx); 472 BN_CTX_free(ctx); 473 } 474 if (buf != NULL) { 475 explicit_bzero(buf, num); 476 free(buf); 477 } 478 return r; 479 } 480 481 static int 482 RSA_eay_private_decrypt(int flen, const unsigned char *from, unsigned char *to, 483 RSA *rsa, int padding) 484 { 485 BIGNUM *f, *ret; 486 int j, num = 0, r = -1; 487 unsigned char *p; 488 unsigned char *buf = NULL; 489 BN_CTX *ctx = NULL; 490 int local_blinding = 0; 491 /* 492 * Used only if the blinding structure is shared. A non-NULL unblind 493 * instructs rsa_blinding_convert() and rsa_blinding_invert() to store 494 * the unblinding factor outside the blinding structure. 495 */ 496 BIGNUM *unblind = NULL; 497 BN_BLINDING *blinding = NULL; 498 499 if ((ctx = BN_CTX_new()) == NULL) 500 goto err; 501 502 BN_CTX_start(ctx); 503 f = BN_CTX_get(ctx); 504 ret = BN_CTX_get(ctx); 505 num = BN_num_bytes(rsa->n); 506 buf = malloc(num); 507 508 if (!f || !ret || !buf) { 509 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE); 510 goto err; 511 } 512 513 /* This check was for equality but PGP does evil things 514 * and chops off the top '0' bytes */ 515 if (flen > num) { 516 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 517 RSA_R_DATA_GREATER_THAN_MOD_LEN); 518 goto err; 519 } 520 521 /* make data into a big number */ 522 if (BN_bin2bn(from, (int)flen, f) == NULL) 523 goto err; 524 525 if (BN_ucmp(f, rsa->n) >= 0) { 526 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 527 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 528 goto err; 529 } 530 531 if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) { 532 blinding = rsa_get_blinding(rsa, &local_blinding, ctx); 533 if (blinding == NULL) { 534 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 535 ERR_R_INTERNAL_ERROR); 536 goto err; 537 } 538 } 539 540 if (blinding != NULL) { 541 if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) { 542 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 543 ERR_R_MALLOC_FAILURE); 544 goto err; 545 } 546 if (!rsa_blinding_convert(blinding, f, unblind, ctx)) 547 goto err; 548 } 549 550 /* do the decrypt */ 551 if ((rsa->flags & RSA_FLAG_EXT_PKEY) || 552 (rsa->p != NULL && rsa->q != NULL && rsa->dmp1 != NULL && 553 rsa->dmq1 != NULL && rsa->iqmp != NULL)) { 554 if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) 555 goto err; 556 } else { 557 BIGNUM d; 558 559 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 560 561 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 562 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 563 CRYPTO_LOCK_RSA, rsa->n, ctx)) 564 goto err; 565 566 if (!rsa->meth->bn_mod_exp(ret, f, &d, rsa->n, ctx, 567 rsa->_method_mod_n)) { 568 goto err; 569 } 570 } 571 572 if (blinding) 573 if (!rsa_blinding_invert(blinding, ret, unblind, ctx)) 574 goto err; 575 576 p = buf; 577 j = BN_bn2bin(ret, p); /* j is only used with no-padding mode */ 578 579 switch (padding) { 580 case RSA_PKCS1_PADDING: 581 r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num); 582 break; 583 #ifndef OPENSSL_NO_SHA 584 case RSA_PKCS1_OAEP_PADDING: 585 r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0); 586 break; 587 #endif 588 case RSA_SSLV23_PADDING: 589 r = RSA_padding_check_SSLv23(to, num, buf, j, num); 590 break; 591 case RSA_NO_PADDING: 592 r = RSA_padding_check_none(to, num, buf, j, num); 593 break; 594 default: 595 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 596 RSA_R_UNKNOWN_PADDING_TYPE); 597 goto err; 598 } 599 if (r < 0) 600 RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, 601 RSA_R_PADDING_CHECK_FAILED); 602 603 err: 604 if (ctx != NULL) { 605 BN_CTX_end(ctx); 606 BN_CTX_free(ctx); 607 } 608 if (buf != NULL) { 609 explicit_bzero(buf, num); 610 free(buf); 611 } 612 return r; 613 } 614 615 /* signature verification */ 616 static int 617 RSA_eay_public_decrypt(int flen, const unsigned char *from, unsigned char *to, 618 RSA *rsa, int padding) 619 { 620 BIGNUM *f, *ret; 621 int i, num = 0, r = -1; 622 unsigned char *p; 623 unsigned char *buf = NULL; 624 BN_CTX *ctx = NULL; 625 626 if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) { 627 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE); 628 return -1; 629 } 630 631 if (BN_ucmp(rsa->n, rsa->e) <= 0) { 632 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 633 return -1; 634 } 635 636 /* for large moduli, enforce exponent limit */ 637 if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) { 638 if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) { 639 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE); 640 return -1; 641 } 642 } 643 644 if ((ctx = BN_CTX_new()) == NULL) 645 goto err; 646 647 BN_CTX_start(ctx); 648 f = BN_CTX_get(ctx); 649 ret = BN_CTX_get(ctx); 650 num = BN_num_bytes(rsa->n); 651 buf = malloc(num); 652 653 if (!f || !ret || !buf) { 654 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE); 655 goto err; 656 } 657 658 /* This check was for equality but PGP does evil things 659 * and chops off the top '0' bytes */ 660 if (flen > num) { 661 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 662 RSA_R_DATA_GREATER_THAN_MOD_LEN); 663 goto err; 664 } 665 666 if (BN_bin2bn(from, flen, f) == NULL) 667 goto err; 668 669 if (BN_ucmp(f, rsa->n) >= 0) { 670 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 671 RSA_R_DATA_TOO_LARGE_FOR_MODULUS); 672 goto err; 673 } 674 675 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 676 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 677 CRYPTO_LOCK_RSA, rsa->n, ctx)) 678 goto err; 679 680 if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx, 681 rsa->_method_mod_n)) 682 goto err; 683 684 if (padding == RSA_X931_PADDING && (ret->d[0] & 0xf) != 12) 685 if (!BN_sub(ret, rsa->n, ret)) 686 goto err; 687 688 p = buf; 689 i = BN_bn2bin(ret, p); 690 691 switch (padding) { 692 case RSA_PKCS1_PADDING: 693 r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num); 694 break; 695 case RSA_X931_PADDING: 696 r = RSA_padding_check_X931(to, num, buf, i, num); 697 break; 698 case RSA_NO_PADDING: 699 r = RSA_padding_check_none(to, num, buf, i, num); 700 break; 701 default: 702 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 703 RSA_R_UNKNOWN_PADDING_TYPE); 704 goto err; 705 } 706 if (r < 0) 707 RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, 708 RSA_R_PADDING_CHECK_FAILED); 709 710 err: 711 if (ctx != NULL) { 712 BN_CTX_end(ctx); 713 BN_CTX_free(ctx); 714 } 715 if (buf != NULL) { 716 explicit_bzero(buf, num); 717 free(buf); 718 } 719 return r; 720 } 721 722 static int 723 RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx) 724 { 725 BIGNUM *r1, *m1, *vrfy; 726 BIGNUM dmp1, dmq1, c, pr1; 727 int ret = 0; 728 729 BN_CTX_start(ctx); 730 r1 = BN_CTX_get(ctx); 731 m1 = BN_CTX_get(ctx); 732 vrfy = BN_CTX_get(ctx); 733 if (r1 == NULL || m1 == NULL || vrfy == NULL) { 734 RSAerr(RSA_F_RSA_EAY_MOD_EXP, ERR_R_MALLOC_FAILURE); 735 goto err; 736 } 737 738 { 739 BIGNUM p, q; 740 741 /* 742 * Make sure BN_mod_inverse in Montgomery intialization uses the 743 * BN_FLG_CONSTTIME flag 744 */ 745 BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME); 746 BN_with_flags(&q, rsa->q, BN_FLG_CONSTTIME); 747 748 if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) { 749 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, 750 CRYPTO_LOCK_RSA, &p, ctx) || 751 !BN_MONT_CTX_set_locked(&rsa->_method_mod_q, 752 CRYPTO_LOCK_RSA, &q, ctx)) { 753 goto err; 754 } 755 } 756 } 757 758 if (rsa->flags & RSA_FLAG_CACHE_PUBLIC) 759 if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, 760 CRYPTO_LOCK_RSA, rsa->n, ctx)) 761 goto err; 762 763 /* compute I mod q */ 764 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 765 766 if (!BN_mod(r1, &c, rsa->q, ctx)) 767 goto err; 768 769 /* compute r1^dmq1 mod q */ 770 BN_with_flags(&dmq1, rsa->dmq1, BN_FLG_CONSTTIME); 771 772 if (!rsa->meth->bn_mod_exp(m1, r1, &dmq1, rsa->q, ctx, 773 rsa->_method_mod_q)) 774 goto err; 775 776 /* compute I mod p */ 777 BN_with_flags(&c, I, BN_FLG_CONSTTIME); 778 779 if (!BN_mod(r1, &c, rsa->p, ctx)) 780 goto err; 781 782 /* compute r1^dmp1 mod p */ 783 BN_with_flags(&dmp1, rsa->dmp1, BN_FLG_CONSTTIME); 784 785 if (!rsa->meth->bn_mod_exp(r0, r1, &dmp1, rsa->p, ctx, 786 rsa->_method_mod_p)) 787 goto err; 788 789 if (!BN_sub(r0, r0, m1)) 790 goto err; 791 792 /* 793 * This will help stop the size of r0 increasing, which does 794 * affect the multiply if it optimised for a power of 2 size 795 */ 796 if (BN_is_negative(r0)) 797 if (!BN_add(r0, r0, rsa->p)) 798 goto err; 799 800 if (!BN_mul(r1, r0, rsa->iqmp, ctx)) 801 goto err; 802 803 /* Turn BN_FLG_CONSTTIME flag on before division operation */ 804 BN_with_flags(&pr1, r1, BN_FLG_CONSTTIME); 805 806 if (!BN_mod(r0, &pr1, rsa->p, ctx)) 807 goto err; 808 809 /* 810 * If p < q it is occasionally possible for the correction of 811 * adding 'p' if r0 is negative above to leave the result still 812 * negative. This can break the private key operations: the following 813 * second correction should *always* correct this rare occurrence. 814 * This will *never* happen with OpenSSL generated keys because 815 * they ensure p > q [steve] 816 */ 817 if (BN_is_negative(r0)) 818 if (!BN_add(r0, r0, rsa->p)) 819 goto err; 820 if (!BN_mul(r1, r0, rsa->q, ctx)) 821 goto err; 822 if (!BN_add(r0, r1, m1)) 823 goto err; 824 825 if (rsa->e && rsa->n) { 826 if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx, 827 rsa->_method_mod_n)) 828 goto err; 829 /* 830 * If 'I' was greater than (or equal to) rsa->n, the operation 831 * will be equivalent to using 'I mod n'. However, the result of 832 * the verify will *always* be less than 'n' so we don't check 833 * for absolute equality, just congruency. 834 */ 835 if (!BN_sub(vrfy, vrfy, I)) 836 goto err; 837 if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) 838 goto err; 839 if (BN_is_negative(vrfy)) 840 if (!BN_add(vrfy, vrfy, rsa->n)) 841 goto err; 842 if (!BN_is_zero(vrfy)) { 843 /* 844 * 'I' and 'vrfy' aren't congruent mod n. Don't leak 845 * miscalculated CRT output, just do a raw (slower) 846 * mod_exp and return that instead. 847 */ 848 BIGNUM d; 849 850 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME); 851 852 if (!rsa->meth->bn_mod_exp(r0, I, &d, rsa->n, ctx, 853 rsa->_method_mod_n)) { 854 goto err; 855 } 856 } 857 } 858 ret = 1; 859 err: 860 BN_CTX_end(ctx); 861 return ret; 862 } 863 864 static int 865 RSA_eay_init(RSA *rsa) 866 { 867 rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE; 868 return 1; 869 } 870 871 static int 872 RSA_eay_finish(RSA *rsa) 873 { 874 BN_MONT_CTX_free(rsa->_method_mod_n); 875 BN_MONT_CTX_free(rsa->_method_mod_p); 876 BN_MONT_CTX_free(rsa->_method_mod_q); 877 878 return 1; 879 } 880