rsa.c (94284B)
1 /* 2 * The RSA public-key cryptosystem 3 * 4 * Copyright The Mbed TLS Contributors 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 */ 7 8 /* 9 * The following sources were referenced in the design of this implementation 10 * of the RSA algorithm: 11 * 12 * [1] A method for obtaining digital signatures and public-key cryptosystems 13 * R Rivest, A Shamir, and L Adleman 14 * http://people.csail.mit.edu/rivest/pubs.html#RSA78 15 * 16 * [2] Handbook of Applied Cryptography - 1997, Chapter 8 17 * Menezes, van Oorschot and Vanstone 18 * 19 * [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks 20 * Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and 21 * Stefan Mangard 22 * https://arxiv.org/abs/1702.08719v2 23 * 24 */ 25 26 #include "common.h" 27 28 #if defined(MBEDTLS_RSA_C) 29 30 #include "mbedtls/rsa.h" 31 #include "bignum_core.h" 32 #include "bignum_internal.h" 33 #include "rsa_alt_helpers.h" 34 #include "rsa_internal.h" 35 #include "mbedtls/oid.h" 36 #include "mbedtls/asn1write.h" 37 #include "mbedtls/platform_util.h" 38 #include "mbedtls/error.h" 39 #include "constant_time_internal.h" 40 #include "mbedtls/constant_time.h" 41 #include "md_psa.h" 42 43 #include <string.h> 44 45 #if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) && !defined(__NetBSD__) 46 #include <stdlib.h> 47 #endif 48 49 #include "mbedtls/platform.h" 50 51 /* 52 * Wrapper around mbedtls_asn1_get_mpi() that rejects zero. 53 * 54 * The value zero is: 55 * - never a valid value for an RSA parameter 56 * - interpreted as "omitted, please reconstruct" by mbedtls_rsa_complete(). 57 * 58 * Since values can't be omitted in PKCS#1, passing a zero value to 59 * rsa_complete() would be incorrect, so reject zero values early. 60 */ 61 static int asn1_get_nonzero_mpi(unsigned char **p, 62 const unsigned char *end, 63 mbedtls_mpi *X) 64 { 65 int ret; 66 67 ret = mbedtls_asn1_get_mpi(p, end, X); 68 if (ret != 0) { 69 return ret; 70 } 71 72 if (mbedtls_mpi_cmp_int(X, 0) == 0) { 73 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 74 } 75 76 return 0; 77 } 78 79 int mbedtls_rsa_parse_key(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen) 80 { 81 int ret, version; 82 size_t len; 83 unsigned char *p, *end; 84 85 mbedtls_mpi T; 86 mbedtls_mpi_init(&T); 87 88 p = (unsigned char *) key; 89 end = p + keylen; 90 91 /* 92 * This function parses the RSAPrivateKey (PKCS#1) 93 * 94 * RSAPrivateKey ::= SEQUENCE { 95 * version Version, 96 * modulus INTEGER, -- n 97 * publicExponent INTEGER, -- e 98 * privateExponent INTEGER, -- d 99 * prime1 INTEGER, -- p 100 * prime2 INTEGER, -- q 101 * exponent1 INTEGER, -- d mod (p-1) 102 * exponent2 INTEGER, -- d mod (q-1) 103 * coefficient INTEGER, -- (inverse of q) mod p 104 * otherPrimeInfos OtherPrimeInfos OPTIONAL 105 * } 106 */ 107 if ((ret = mbedtls_asn1_get_tag(&p, end, &len, 108 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { 109 return ret; 110 } 111 112 if (end != p + len) { 113 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 114 } 115 116 if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) { 117 return ret; 118 } 119 120 if (version != 0) { 121 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 122 } 123 124 /* Import N */ 125 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 126 (ret = mbedtls_rsa_import(rsa, &T, NULL, NULL, 127 NULL, NULL)) != 0) { 128 goto cleanup; 129 } 130 131 /* Import E */ 132 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 133 (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL, 134 NULL, &T)) != 0) { 135 goto cleanup; 136 } 137 138 /* Import D */ 139 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 140 (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL, 141 &T, NULL)) != 0) { 142 goto cleanup; 143 } 144 145 /* Import P */ 146 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 147 (ret = mbedtls_rsa_import(rsa, NULL, &T, NULL, 148 NULL, NULL)) != 0) { 149 goto cleanup; 150 } 151 152 /* Import Q */ 153 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 154 (ret = mbedtls_rsa_import(rsa, NULL, NULL, &T, 155 NULL, NULL)) != 0) { 156 goto cleanup; 157 } 158 159 #if !defined(MBEDTLS_RSA_NO_CRT) && !defined(MBEDTLS_RSA_ALT) 160 /* 161 * The RSA CRT parameters DP, DQ and QP are nominally redundant, in 162 * that they can be easily recomputed from D, P and Q. However by 163 * parsing them from the PKCS1 structure it is possible to avoid 164 * recalculating them which both reduces the overhead of loading 165 * RSA private keys into memory and also avoids side channels which 166 * can arise when computing those values, since all of D, P, and Q 167 * are secret. See https://eprint.iacr.org/2020/055 for a 168 * description of one such attack. 169 */ 170 171 /* Import DP */ 172 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 173 (ret = mbedtls_mpi_copy(&rsa->DP, &T)) != 0) { 174 goto cleanup; 175 } 176 177 /* Import DQ */ 178 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 179 (ret = mbedtls_mpi_copy(&rsa->DQ, &T)) != 0) { 180 goto cleanup; 181 } 182 183 /* Import QP */ 184 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 185 (ret = mbedtls_mpi_copy(&rsa->QP, &T)) != 0) { 186 goto cleanup; 187 } 188 189 #else 190 /* Verify existence of the CRT params */ 191 if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 192 (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || 193 (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0) { 194 goto cleanup; 195 } 196 #endif 197 198 /* rsa_complete() doesn't complete anything with the default 199 * implementation but is still called: 200 * - for the benefit of alternative implementation that may want to 201 * pre-compute stuff beyond what's provided (eg Montgomery factors) 202 * - as is also sanity-checks the key 203 * 204 * Furthermore, we also check the public part for consistency with 205 * mbedtls_pk_parse_pubkey(), as it includes size minima for example. 206 */ 207 if ((ret = mbedtls_rsa_complete(rsa)) != 0 || 208 (ret = mbedtls_rsa_check_pubkey(rsa)) != 0) { 209 goto cleanup; 210 } 211 212 if (p != end) { 213 ret = MBEDTLS_ERR_ASN1_LENGTH_MISMATCH; 214 } 215 216 cleanup: 217 218 mbedtls_mpi_free(&T); 219 220 if (ret != 0) { 221 mbedtls_rsa_free(rsa); 222 } 223 224 return ret; 225 } 226 227 int mbedtls_rsa_parse_pubkey(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen) 228 { 229 unsigned char *p = (unsigned char *) key; 230 unsigned char *end = (unsigned char *) (key + keylen); 231 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 232 size_t len; 233 234 /* 235 * RSAPublicKey ::= SEQUENCE { 236 * modulus INTEGER, -- n 237 * publicExponent INTEGER -- e 238 * } 239 */ 240 241 if ((ret = mbedtls_asn1_get_tag(&p, end, &len, 242 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { 243 return ret; 244 } 245 246 if (end != p + len) { 247 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 248 } 249 250 /* Import N */ 251 if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) { 252 return ret; 253 } 254 255 if ((ret = mbedtls_rsa_import_raw(rsa, p, len, NULL, 0, NULL, 0, 256 NULL, 0, NULL, 0)) != 0) { 257 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 258 } 259 260 p += len; 261 262 /* Import E */ 263 if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) { 264 return ret; 265 } 266 267 if ((ret = mbedtls_rsa_import_raw(rsa, NULL, 0, NULL, 0, NULL, 0, 268 NULL, 0, p, len)) != 0) { 269 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 270 } 271 272 p += len; 273 274 if (mbedtls_rsa_complete(rsa) != 0 || 275 mbedtls_rsa_check_pubkey(rsa) != 0) { 276 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 277 } 278 279 if (p != end) { 280 return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH; 281 } 282 283 return 0; 284 } 285 286 int mbedtls_rsa_write_key(const mbedtls_rsa_context *rsa, unsigned char *start, 287 unsigned char **p) 288 { 289 size_t len = 0; 290 int ret; 291 292 mbedtls_mpi T; /* Temporary holding the exported parameters */ 293 294 /* 295 * Export the parameters one after another to avoid simultaneous copies. 296 */ 297 298 mbedtls_mpi_init(&T); 299 300 /* Export QP */ 301 if ((ret = mbedtls_rsa_export_crt(rsa, NULL, NULL, &T)) != 0 || 302 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 303 goto end_of_export; 304 } 305 len += ret; 306 307 /* Export DQ */ 308 if ((ret = mbedtls_rsa_export_crt(rsa, NULL, &T, NULL)) != 0 || 309 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 310 goto end_of_export; 311 } 312 len += ret; 313 314 /* Export DP */ 315 if ((ret = mbedtls_rsa_export_crt(rsa, &T, NULL, NULL)) != 0 || 316 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 317 goto end_of_export; 318 } 319 len += ret; 320 321 /* Export Q */ 322 if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, &T, NULL, NULL)) != 0 || 323 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 324 goto end_of_export; 325 } 326 len += ret; 327 328 /* Export P */ 329 if ((ret = mbedtls_rsa_export(rsa, NULL, &T, NULL, NULL, NULL)) != 0 || 330 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 331 goto end_of_export; 332 } 333 len += ret; 334 335 /* Export D */ 336 if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, &T, NULL)) != 0 || 337 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 338 goto end_of_export; 339 } 340 len += ret; 341 342 /* Export E */ 343 if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 || 344 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 345 goto end_of_export; 346 } 347 len += ret; 348 349 /* Export N */ 350 if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 || 351 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 352 goto end_of_export; 353 } 354 len += ret; 355 356 end_of_export: 357 358 mbedtls_mpi_free(&T); 359 if (ret < 0) { 360 return ret; 361 } 362 363 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, start, 0)); 364 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); 365 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, 366 MBEDTLS_ASN1_CONSTRUCTED | 367 MBEDTLS_ASN1_SEQUENCE)); 368 369 return (int) len; 370 } 371 372 /* 373 * RSAPublicKey ::= SEQUENCE { 374 * modulus INTEGER, -- n 375 * publicExponent INTEGER -- e 376 * } 377 */ 378 int mbedtls_rsa_write_pubkey(const mbedtls_rsa_context *rsa, unsigned char *start, 379 unsigned char **p) 380 { 381 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 382 size_t len = 0; 383 mbedtls_mpi T; 384 385 mbedtls_mpi_init(&T); 386 387 /* Export E */ 388 if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 || 389 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 390 goto end_of_export; 391 } 392 len += ret; 393 394 /* Export N */ 395 if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 || 396 (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { 397 goto end_of_export; 398 } 399 len += ret; 400 401 end_of_export: 402 403 mbedtls_mpi_free(&T); 404 if (ret < 0) { 405 return ret; 406 } 407 408 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); 409 MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED | 410 MBEDTLS_ASN1_SEQUENCE)); 411 412 return (int) len; 413 } 414 415 #if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT) 416 417 /** This function performs the unpadding part of a PKCS#1 v1.5 decryption 418 * operation (EME-PKCS1-v1_5 decoding). 419 * 420 * \note The return value from this function is a sensitive value 421 * (this is unusual). #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE shouldn't happen 422 * in a well-written application, but 0 vs #MBEDTLS_ERR_RSA_INVALID_PADDING 423 * is often a situation that an attacker can provoke and leaking which 424 * one is the result is precisely the information the attacker wants. 425 * 426 * \param input The input buffer which is the payload inside PKCS#1v1.5 427 * encryption padding, called the "encoded message EM" 428 * by the terminology. 429 * \param ilen The length of the payload in the \p input buffer. 430 * \param output The buffer for the payload, called "message M" by the 431 * PKCS#1 terminology. This must be a writable buffer of 432 * length \p output_max_len bytes. 433 * \param olen The address at which to store the length of 434 * the payload. This must not be \c NULL. 435 * \param output_max_len The length in bytes of the output buffer \p output. 436 * 437 * \return \c 0 on success. 438 * \return #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE 439 * The output buffer is too small for the unpadded payload. 440 * \return #MBEDTLS_ERR_RSA_INVALID_PADDING 441 * The input doesn't contain properly formatted padding. 442 */ 443 static int mbedtls_ct_rsaes_pkcs1_v15_unpadding(unsigned char *input, 444 size_t ilen, 445 unsigned char *output, 446 size_t output_max_len, 447 size_t *olen) 448 { 449 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 450 size_t i, plaintext_max_size; 451 452 /* The following variables take sensitive values: their value must 453 * not leak into the observable behavior of the function other than 454 * the designated outputs (output, olen, return value). Otherwise 455 * this would open the execution of the function to 456 * side-channel-based variants of the Bleichenbacher padding oracle 457 * attack. Potential side channels include overall timing, memory 458 * access patterns (especially visible to an adversary who has access 459 * to a shared memory cache), and branches (especially visible to 460 * an adversary who has access to a shared code cache or to a shared 461 * branch predictor). */ 462 size_t pad_count = 0; 463 mbedtls_ct_condition_t bad; 464 mbedtls_ct_condition_t pad_done; 465 size_t plaintext_size = 0; 466 mbedtls_ct_condition_t output_too_large; 467 468 plaintext_max_size = (output_max_len > ilen - 11) ? ilen - 11 469 : output_max_len; 470 471 /* Check and get padding length in constant time and constant 472 * memory trace. The first byte must be 0. */ 473 bad = mbedtls_ct_bool(input[0]); 474 475 476 /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00 477 * where PS must be at least 8 nonzero bytes. */ 478 bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(input[1], MBEDTLS_RSA_CRYPT)); 479 480 /* Read the whole buffer. Set pad_done to nonzero if we find 481 * the 0x00 byte and remember the padding length in pad_count. */ 482 pad_done = MBEDTLS_CT_FALSE; 483 for (i = 2; i < ilen; i++) { 484 mbedtls_ct_condition_t found = mbedtls_ct_uint_eq(input[i], 0); 485 pad_done = mbedtls_ct_bool_or(pad_done, found); 486 pad_count += mbedtls_ct_uint_if_else_0(mbedtls_ct_bool_not(pad_done), 1); 487 } 488 489 /* If pad_done is still zero, there's no data, only unfinished padding. */ 490 bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool_not(pad_done)); 491 492 /* There must be at least 8 bytes of padding. */ 493 bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_gt(8, pad_count)); 494 495 /* If the padding is valid, set plaintext_size to the number of 496 * remaining bytes after stripping the padding. If the padding 497 * is invalid, avoid leaking this fact through the size of the 498 * output: use the maximum message size that fits in the output 499 * buffer. Do it without branches to avoid leaking the padding 500 * validity through timing. RSA keys are small enough that all the 501 * size_t values involved fit in unsigned int. */ 502 plaintext_size = mbedtls_ct_uint_if( 503 bad, (unsigned) plaintext_max_size, 504 (unsigned) (ilen - pad_count - 3)); 505 506 /* Set output_too_large to 0 if the plaintext fits in the output 507 * buffer and to 1 otherwise. */ 508 output_too_large = mbedtls_ct_uint_gt(plaintext_size, 509 plaintext_max_size); 510 511 /* Set ret without branches to avoid timing attacks. Return: 512 * - INVALID_PADDING if the padding is bad (bad != 0). 513 * - OUTPUT_TOO_LARGE if the padding is good but the decrypted 514 * plaintext does not fit in the output buffer. 515 * - 0 if the padding is correct. */ 516 ret = mbedtls_ct_error_if( 517 bad, 518 MBEDTLS_ERR_RSA_INVALID_PADDING, 519 mbedtls_ct_error_if_else_0(output_too_large, MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE) 520 ); 521 522 /* If the padding is bad or the plaintext is too large, zero the 523 * data that we're about to copy to the output buffer. 524 * We need to copy the same amount of data 525 * from the same buffer whether the padding is good or not to 526 * avoid leaking the padding validity through overall timing or 527 * through memory or cache access patterns. */ 528 mbedtls_ct_zeroize_if(mbedtls_ct_bool_or(bad, output_too_large), input + 11, ilen - 11); 529 530 /* If the plaintext is too large, truncate it to the buffer size. 531 * Copy anyway to avoid revealing the length through timing, because 532 * revealing the length is as bad as revealing the padding validity 533 * for a Bleichenbacher attack. */ 534 plaintext_size = mbedtls_ct_uint_if(output_too_large, 535 (unsigned) plaintext_max_size, 536 (unsigned) plaintext_size); 537 538 /* Move the plaintext to the leftmost position where it can start in 539 * the working buffer, i.e. make it start plaintext_max_size from 540 * the end of the buffer. Do this with a memory access trace that 541 * does not depend on the plaintext size. After this move, the 542 * starting location of the plaintext is no longer sensitive 543 * information. */ 544 mbedtls_ct_memmove_left(input + ilen - plaintext_max_size, 545 plaintext_max_size, 546 plaintext_max_size - plaintext_size); 547 548 /* Finally copy the decrypted plaintext plus trailing zeros into the output 549 * buffer. If output_max_len is 0, then output may be an invalid pointer 550 * and the result of memcpy() would be undefined; prevent undefined 551 * behavior making sure to depend only on output_max_len (the size of the 552 * user-provided output buffer), which is independent from plaintext 553 * length, validity of padding, success of the decryption, and other 554 * secrets. */ 555 if (output_max_len != 0) { 556 memcpy(output, input + ilen - plaintext_max_size, plaintext_max_size); 557 } 558 559 /* Report the amount of data we copied to the output buffer. In case 560 * of errors (bad padding or output too large), the value of *olen 561 * when this function returns is not specified. Making it equivalent 562 * to the good case limits the risks of leaking the padding validity. */ 563 *olen = plaintext_size; 564 565 return ret; 566 } 567 568 #endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */ 569 570 #if !defined(MBEDTLS_RSA_ALT) 571 572 int mbedtls_rsa_import(mbedtls_rsa_context *ctx, 573 const mbedtls_mpi *N, 574 const mbedtls_mpi *P, const mbedtls_mpi *Q, 575 const mbedtls_mpi *D, const mbedtls_mpi *E) 576 { 577 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 578 579 if ((N != NULL && (ret = mbedtls_mpi_copy(&ctx->N, N)) != 0) || 580 (P != NULL && (ret = mbedtls_mpi_copy(&ctx->P, P)) != 0) || 581 (Q != NULL && (ret = mbedtls_mpi_copy(&ctx->Q, Q)) != 0) || 582 (D != NULL && (ret = mbedtls_mpi_copy(&ctx->D, D)) != 0) || 583 (E != NULL && (ret = mbedtls_mpi_copy(&ctx->E, E)) != 0)) { 584 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 585 } 586 587 if (N != NULL) { 588 ctx->len = mbedtls_mpi_size(&ctx->N); 589 } 590 591 return 0; 592 } 593 594 int mbedtls_rsa_import_raw(mbedtls_rsa_context *ctx, 595 unsigned char const *N, size_t N_len, 596 unsigned char const *P, size_t P_len, 597 unsigned char const *Q, size_t Q_len, 598 unsigned char const *D, size_t D_len, 599 unsigned char const *E, size_t E_len) 600 { 601 int ret = 0; 602 603 if (N != NULL) { 604 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->N, N, N_len)); 605 ctx->len = mbedtls_mpi_size(&ctx->N); 606 } 607 608 if (P != NULL) { 609 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->P, P, P_len)); 610 } 611 612 if (Q != NULL) { 613 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->Q, Q, Q_len)); 614 } 615 616 if (D != NULL) { 617 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->D, D, D_len)); 618 } 619 620 if (E != NULL) { 621 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->E, E, E_len)); 622 } 623 624 cleanup: 625 626 if (ret != 0) { 627 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 628 } 629 630 return 0; 631 } 632 633 /* 634 * Checks whether the context fields are set in such a way 635 * that the RSA primitives will be able to execute without error. 636 * It does *not* make guarantees for consistency of the parameters. 637 */ 638 static int rsa_check_context(mbedtls_rsa_context const *ctx, int is_priv, 639 int blinding_needed) 640 { 641 #if !defined(MBEDTLS_RSA_NO_CRT) 642 /* blinding_needed is only used for NO_CRT to decide whether 643 * P,Q need to be present or not. */ 644 ((void) blinding_needed); 645 #endif 646 647 if (ctx->len != mbedtls_mpi_size(&ctx->N) || 648 ctx->len > MBEDTLS_MPI_MAX_SIZE) { 649 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 650 } 651 652 /* 653 * 1. Modular exponentiation needs positive, odd moduli. 654 */ 655 656 /* Modular exponentiation wrt. N is always used for 657 * RSA public key operations. */ 658 if (mbedtls_mpi_cmp_int(&ctx->N, 0) <= 0 || 659 mbedtls_mpi_get_bit(&ctx->N, 0) == 0) { 660 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 661 } 662 663 #if !defined(MBEDTLS_RSA_NO_CRT) 664 /* Modular exponentiation for P and Q is only 665 * used for private key operations and if CRT 666 * is used. */ 667 if (is_priv && 668 (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 || 669 mbedtls_mpi_get_bit(&ctx->P, 0) == 0 || 670 mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0 || 671 mbedtls_mpi_get_bit(&ctx->Q, 0) == 0)) { 672 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 673 } 674 #endif /* !MBEDTLS_RSA_NO_CRT */ 675 676 /* 677 * 2. Exponents must be positive 678 */ 679 680 /* Always need E for public key operations */ 681 if (mbedtls_mpi_cmp_int(&ctx->E, 0) <= 0) { 682 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 683 } 684 685 #if defined(MBEDTLS_RSA_NO_CRT) 686 /* For private key operations, use D or DP & DQ 687 * as (unblinded) exponents. */ 688 if (is_priv && mbedtls_mpi_cmp_int(&ctx->D, 0) <= 0) { 689 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 690 } 691 #else 692 if (is_priv && 693 (mbedtls_mpi_cmp_int(&ctx->DP, 0) <= 0 || 694 mbedtls_mpi_cmp_int(&ctx->DQ, 0) <= 0)) { 695 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 696 } 697 #endif /* MBEDTLS_RSA_NO_CRT */ 698 699 /* Blinding shouldn't make exponents negative either, 700 * so check that P, Q >= 1 if that hasn't yet been 701 * done as part of 1. */ 702 #if defined(MBEDTLS_RSA_NO_CRT) 703 if (is_priv && blinding_needed && 704 (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 || 705 mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0)) { 706 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 707 } 708 #endif 709 710 /* It wouldn't lead to an error if it wasn't satisfied, 711 * but check for QP >= 1 nonetheless. */ 712 #if !defined(MBEDTLS_RSA_NO_CRT) 713 if (is_priv && 714 mbedtls_mpi_cmp_int(&ctx->QP, 0) <= 0) { 715 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 716 } 717 #endif 718 719 return 0; 720 } 721 722 int mbedtls_rsa_complete(mbedtls_rsa_context *ctx) 723 { 724 int ret = 0; 725 int have_N, have_P, have_Q, have_D, have_E; 726 #if !defined(MBEDTLS_RSA_NO_CRT) 727 int have_DP, have_DQ, have_QP; 728 #endif 729 int n_missing, pq_missing, d_missing, is_pub, is_priv; 730 731 have_N = (mbedtls_mpi_cmp_int(&ctx->N, 0) != 0); 732 have_P = (mbedtls_mpi_cmp_int(&ctx->P, 0) != 0); 733 have_Q = (mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0); 734 have_D = (mbedtls_mpi_cmp_int(&ctx->D, 0) != 0); 735 have_E = (mbedtls_mpi_cmp_int(&ctx->E, 0) != 0); 736 737 #if !defined(MBEDTLS_RSA_NO_CRT) 738 have_DP = (mbedtls_mpi_cmp_int(&ctx->DP, 0) != 0); 739 have_DQ = (mbedtls_mpi_cmp_int(&ctx->DQ, 0) != 0); 740 have_QP = (mbedtls_mpi_cmp_int(&ctx->QP, 0) != 0); 741 #endif 742 743 /* 744 * Check whether provided parameters are enough 745 * to deduce all others. The following incomplete 746 * parameter sets for private keys are supported: 747 * 748 * (1) P, Q missing. 749 * (2) D and potentially N missing. 750 * 751 */ 752 753 n_missing = have_P && have_Q && have_D && have_E; 754 pq_missing = have_N && !have_P && !have_Q && have_D && have_E; 755 d_missing = have_P && have_Q && !have_D && have_E; 756 is_pub = have_N && !have_P && !have_Q && !have_D && have_E; 757 758 /* These three alternatives are mutually exclusive */ 759 is_priv = n_missing || pq_missing || d_missing; 760 761 if (!is_priv && !is_pub) { 762 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 763 } 764 765 /* 766 * Step 1: Deduce N if P, Q are provided. 767 */ 768 769 if (!have_N && have_P && have_Q) { 770 if ((ret = mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P, 771 &ctx->Q)) != 0) { 772 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 773 } 774 775 ctx->len = mbedtls_mpi_size(&ctx->N); 776 } 777 778 /* 779 * Step 2: Deduce and verify all remaining core parameters. 780 */ 781 782 if (pq_missing) { 783 ret = mbedtls_rsa_deduce_primes(&ctx->N, &ctx->E, &ctx->D, 784 &ctx->P, &ctx->Q); 785 if (ret != 0) { 786 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 787 } 788 789 } else if (d_missing) { 790 if ((ret = mbedtls_rsa_deduce_private_exponent(&ctx->P, 791 &ctx->Q, 792 &ctx->E, 793 &ctx->D)) != 0) { 794 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 795 } 796 } 797 798 /* 799 * Step 3: Deduce all additional parameters specific 800 * to our current RSA implementation. 801 */ 802 803 #if !defined(MBEDTLS_RSA_NO_CRT) 804 if (is_priv && !(have_DP && have_DQ && have_QP)) { 805 ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, 806 &ctx->DP, &ctx->DQ, &ctx->QP); 807 if (ret != 0) { 808 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 809 } 810 } 811 #endif /* MBEDTLS_RSA_NO_CRT */ 812 813 /* 814 * Step 3: Basic sanity checks 815 */ 816 817 return rsa_check_context(ctx, is_priv, 1); 818 } 819 820 int mbedtls_rsa_export_raw(const mbedtls_rsa_context *ctx, 821 unsigned char *N, size_t N_len, 822 unsigned char *P, size_t P_len, 823 unsigned char *Q, size_t Q_len, 824 unsigned char *D, size_t D_len, 825 unsigned char *E, size_t E_len) 826 { 827 int ret = 0; 828 int is_priv; 829 830 /* Check if key is private or public */ 831 is_priv = 832 mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && 833 mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && 834 mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && 835 mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && 836 mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; 837 838 if (!is_priv) { 839 /* If we're trying to export private parameters for a public key, 840 * something must be wrong. */ 841 if (P != NULL || Q != NULL || D != NULL) { 842 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 843 } 844 845 } 846 847 if (N != NULL) { 848 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->N, N, N_len)); 849 } 850 851 if (P != NULL) { 852 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->P, P, P_len)); 853 } 854 855 if (Q != NULL) { 856 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->Q, Q, Q_len)); 857 } 858 859 if (D != NULL) { 860 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->D, D, D_len)); 861 } 862 863 if (E != NULL) { 864 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->E, E, E_len)); 865 } 866 867 cleanup: 868 869 return ret; 870 } 871 872 int mbedtls_rsa_export(const mbedtls_rsa_context *ctx, 873 mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q, 874 mbedtls_mpi *D, mbedtls_mpi *E) 875 { 876 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 877 int is_priv; 878 879 /* Check if key is private or public */ 880 is_priv = 881 mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && 882 mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && 883 mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && 884 mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && 885 mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; 886 887 if (!is_priv) { 888 /* If we're trying to export private parameters for a public key, 889 * something must be wrong. */ 890 if (P != NULL || Q != NULL || D != NULL) { 891 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 892 } 893 894 } 895 896 /* Export all requested core parameters. */ 897 898 if ((N != NULL && (ret = mbedtls_mpi_copy(N, &ctx->N)) != 0) || 899 (P != NULL && (ret = mbedtls_mpi_copy(P, &ctx->P)) != 0) || 900 (Q != NULL && (ret = mbedtls_mpi_copy(Q, &ctx->Q)) != 0) || 901 (D != NULL && (ret = mbedtls_mpi_copy(D, &ctx->D)) != 0) || 902 (E != NULL && (ret = mbedtls_mpi_copy(E, &ctx->E)) != 0)) { 903 return ret; 904 } 905 906 return 0; 907 } 908 909 /* 910 * Export CRT parameters 911 * This must also be implemented if CRT is not used, for being able to 912 * write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt 913 * can be used in this case. 914 */ 915 int mbedtls_rsa_export_crt(const mbedtls_rsa_context *ctx, 916 mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP) 917 { 918 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 919 int is_priv; 920 921 /* Check if key is private or public */ 922 is_priv = 923 mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && 924 mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && 925 mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && 926 mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && 927 mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; 928 929 if (!is_priv) { 930 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 931 } 932 933 #if !defined(MBEDTLS_RSA_NO_CRT) 934 /* Export all requested blinding parameters. */ 935 if ((DP != NULL && (ret = mbedtls_mpi_copy(DP, &ctx->DP)) != 0) || 936 (DQ != NULL && (ret = mbedtls_mpi_copy(DQ, &ctx->DQ)) != 0) || 937 (QP != NULL && (ret = mbedtls_mpi_copy(QP, &ctx->QP)) != 0)) { 938 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 939 } 940 #else 941 if ((ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, 942 DP, DQ, QP)) != 0) { 943 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); 944 } 945 #endif 946 947 return 0; 948 } 949 950 /* 951 * Initialize an RSA context 952 */ 953 void mbedtls_rsa_init(mbedtls_rsa_context *ctx) 954 { 955 memset(ctx, 0, sizeof(mbedtls_rsa_context)); 956 957 ctx->padding = MBEDTLS_RSA_PKCS_V15; 958 ctx->hash_id = MBEDTLS_MD_NONE; 959 960 #if defined(MBEDTLS_THREADING_C) 961 /* Set ctx->ver to nonzero to indicate that the mutex has been 962 * initialized and will need to be freed. */ 963 ctx->ver = 1; 964 mbedtls_mutex_init(&ctx->mutex); 965 #endif 966 } 967 968 /* 969 * Set padding for an existing RSA context 970 */ 971 int mbedtls_rsa_set_padding(mbedtls_rsa_context *ctx, int padding, 972 mbedtls_md_type_t hash_id) 973 { 974 switch (padding) { 975 #if defined(MBEDTLS_PKCS1_V15) 976 case MBEDTLS_RSA_PKCS_V15: 977 break; 978 #endif 979 980 #if defined(MBEDTLS_PKCS1_V21) 981 case MBEDTLS_RSA_PKCS_V21: 982 break; 983 #endif 984 default: 985 return MBEDTLS_ERR_RSA_INVALID_PADDING; 986 } 987 988 #if defined(MBEDTLS_PKCS1_V21) 989 if ((padding == MBEDTLS_RSA_PKCS_V21) && 990 (hash_id != MBEDTLS_MD_NONE)) { 991 /* Just make sure this hash is supported in this build. */ 992 if (mbedtls_md_info_from_type(hash_id) == NULL) { 993 return MBEDTLS_ERR_RSA_INVALID_PADDING; 994 } 995 } 996 #endif /* MBEDTLS_PKCS1_V21 */ 997 998 ctx->padding = padding; 999 ctx->hash_id = hash_id; 1000 1001 return 0; 1002 } 1003 1004 /* 1005 * Get padding mode of initialized RSA context 1006 */ 1007 int mbedtls_rsa_get_padding_mode(const mbedtls_rsa_context *ctx) 1008 { 1009 return ctx->padding; 1010 } 1011 1012 /* 1013 * Get hash identifier of mbedtls_md_type_t type 1014 */ 1015 int mbedtls_rsa_get_md_alg(const mbedtls_rsa_context *ctx) 1016 { 1017 return ctx->hash_id; 1018 } 1019 1020 /* 1021 * Get length in bits of RSA modulus 1022 */ 1023 size_t mbedtls_rsa_get_bitlen(const mbedtls_rsa_context *ctx) 1024 { 1025 return mbedtls_mpi_bitlen(&ctx->N); 1026 } 1027 1028 /* 1029 * Get length in bytes of RSA modulus 1030 */ 1031 size_t mbedtls_rsa_get_len(const mbedtls_rsa_context *ctx) 1032 { 1033 return ctx->len; 1034 } 1035 1036 #if defined(MBEDTLS_GENPRIME) 1037 1038 /* 1039 * Generate an RSA keypair 1040 * 1041 * This generation method follows the RSA key pair generation procedure of 1042 * FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072. 1043 */ 1044 int mbedtls_rsa_gen_key(mbedtls_rsa_context *ctx, 1045 int (*f_rng)(void *, unsigned char *, size_t), 1046 void *p_rng, 1047 unsigned int nbits, int exponent) 1048 { 1049 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1050 mbedtls_mpi H, G, L; 1051 int prime_quality = 0; 1052 1053 /* 1054 * If the modulus is 1024 bit long or shorter, then the security strength of 1055 * the RSA algorithm is less than or equal to 80 bits and therefore an error 1056 * rate of 2^-80 is sufficient. 1057 */ 1058 if (nbits > 1024) { 1059 prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR; 1060 } 1061 1062 mbedtls_mpi_init(&H); 1063 mbedtls_mpi_init(&G); 1064 mbedtls_mpi_init(&L); 1065 1066 if (exponent < 3 || nbits % 2 != 0) { 1067 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1068 goto cleanup; 1069 } 1070 1071 if (nbits < MBEDTLS_RSA_GEN_KEY_MIN_BITS) { 1072 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1073 goto cleanup; 1074 } 1075 1076 /* 1077 * find primes P and Q with Q < P so that: 1078 * 1. |P-Q| > 2^( nbits / 2 - 100 ) 1079 * 2. GCD( E, (P-1)*(Q-1) ) == 1 1080 * 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 ) 1081 */ 1082 MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&ctx->E, exponent)); 1083 1084 do { 1085 MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->P, nbits >> 1, 1086 prime_quality, f_rng, p_rng)); 1087 1088 MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->Q, nbits >> 1, 1089 prime_quality, f_rng, p_rng)); 1090 1091 /* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */ 1092 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&H, &ctx->P, &ctx->Q)); 1093 if (mbedtls_mpi_bitlen(&H) <= ((nbits >= 200) ? ((nbits >> 1) - 99) : 0)) { 1094 continue; 1095 } 1096 1097 /* not required by any standards, but some users rely on the fact that P > Q */ 1098 if (H.s < 0) { 1099 mbedtls_mpi_swap(&ctx->P, &ctx->Q); 1100 } 1101 1102 /* Temporarily replace P,Q by P-1, Q-1 */ 1103 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->P, &ctx->P, 1)); 1104 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->Q, &ctx->Q, 1)); 1105 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&H, &ctx->P, &ctx->Q)); 1106 1107 /* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */ 1108 MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->E, &H)); 1109 if (mbedtls_mpi_cmp_int(&G, 1) != 0) { 1110 continue; 1111 } 1112 1113 /* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */ 1114 MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->P, &ctx->Q)); 1115 MBEDTLS_MPI_CHK(mbedtls_mpi_div_mpi(&L, NULL, &H, &G)); 1116 MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&ctx->D, &ctx->E, &L)); 1117 1118 if (mbedtls_mpi_bitlen(&ctx->D) <= ((nbits + 1) / 2)) { // (FIPS 186-4 §B.3.1 criterion 3(a)) 1119 continue; 1120 } 1121 1122 break; 1123 } while (1); 1124 1125 /* Restore P,Q */ 1126 MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->P, &ctx->P, 1)); 1127 MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->Q, &ctx->Q, 1)); 1128 1129 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P, &ctx->Q)); 1130 1131 ctx->len = mbedtls_mpi_size(&ctx->N); 1132 1133 #if !defined(MBEDTLS_RSA_NO_CRT) 1134 /* 1135 * DP = D mod (P - 1) 1136 * DQ = D mod (Q - 1) 1137 * QP = Q^-1 mod P 1138 */ 1139 MBEDTLS_MPI_CHK(mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, 1140 &ctx->DP, &ctx->DQ, &ctx->QP)); 1141 #endif /* MBEDTLS_RSA_NO_CRT */ 1142 1143 /* Double-check */ 1144 MBEDTLS_MPI_CHK(mbedtls_rsa_check_privkey(ctx)); 1145 1146 cleanup: 1147 1148 mbedtls_mpi_free(&H); 1149 mbedtls_mpi_free(&G); 1150 mbedtls_mpi_free(&L); 1151 1152 if (ret != 0) { 1153 mbedtls_rsa_free(ctx); 1154 1155 if ((-ret & ~0x7f) == 0) { 1156 ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret); 1157 } 1158 return ret; 1159 } 1160 1161 return 0; 1162 } 1163 1164 #endif /* MBEDTLS_GENPRIME */ 1165 1166 /* 1167 * Check a public RSA key 1168 */ 1169 int mbedtls_rsa_check_pubkey(const mbedtls_rsa_context *ctx) 1170 { 1171 if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */) != 0) { 1172 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1173 } 1174 1175 if (mbedtls_mpi_bitlen(&ctx->N) < 128) { 1176 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1177 } 1178 1179 if (mbedtls_mpi_get_bit(&ctx->E, 0) == 0 || 1180 mbedtls_mpi_bitlen(&ctx->E) < 2 || 1181 mbedtls_mpi_cmp_mpi(&ctx->E, &ctx->N) >= 0) { 1182 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1183 } 1184 1185 return 0; 1186 } 1187 1188 /* 1189 * Check for the consistency of all fields in an RSA private key context 1190 */ 1191 int mbedtls_rsa_check_privkey(const mbedtls_rsa_context *ctx) 1192 { 1193 if (mbedtls_rsa_check_pubkey(ctx) != 0 || 1194 rsa_check_context(ctx, 1 /* private */, 1 /* blinding */) != 0) { 1195 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1196 } 1197 1198 if (mbedtls_rsa_validate_params(&ctx->N, &ctx->P, &ctx->Q, 1199 &ctx->D, &ctx->E, NULL, NULL) != 0) { 1200 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1201 } 1202 1203 #if !defined(MBEDTLS_RSA_NO_CRT) 1204 else if (mbedtls_rsa_validate_crt(&ctx->P, &ctx->Q, &ctx->D, 1205 &ctx->DP, &ctx->DQ, &ctx->QP) != 0) { 1206 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1207 } 1208 #endif 1209 1210 return 0; 1211 } 1212 1213 /* 1214 * Check if contexts holding a public and private key match 1215 */ 1216 int mbedtls_rsa_check_pub_priv(const mbedtls_rsa_context *pub, 1217 const mbedtls_rsa_context *prv) 1218 { 1219 if (mbedtls_rsa_check_pubkey(pub) != 0 || 1220 mbedtls_rsa_check_privkey(prv) != 0) { 1221 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1222 } 1223 1224 if (mbedtls_mpi_cmp_mpi(&pub->N, &prv->N) != 0 || 1225 mbedtls_mpi_cmp_mpi(&pub->E, &prv->E) != 0) { 1226 return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; 1227 } 1228 1229 return 0; 1230 } 1231 1232 /* 1233 * Do an RSA public key operation 1234 */ 1235 int mbedtls_rsa_public(mbedtls_rsa_context *ctx, 1236 const unsigned char *input, 1237 unsigned char *output) 1238 { 1239 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1240 size_t olen; 1241 mbedtls_mpi T; 1242 1243 if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */)) { 1244 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1245 } 1246 1247 mbedtls_mpi_init(&T); 1248 1249 #if defined(MBEDTLS_THREADING_C) 1250 if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { 1251 return ret; 1252 } 1253 #endif 1254 1255 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len)); 1256 1257 if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) { 1258 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; 1259 goto cleanup; 1260 } 1261 1262 olen = ctx->len; 1263 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod_unsafe(&T, &T, &ctx->E, &ctx->N, &ctx->RN)); 1264 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen)); 1265 1266 cleanup: 1267 #if defined(MBEDTLS_THREADING_C) 1268 if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { 1269 return MBEDTLS_ERR_THREADING_MUTEX_ERROR; 1270 } 1271 #endif 1272 1273 mbedtls_mpi_free(&T); 1274 1275 if (ret != 0) { 1276 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret); 1277 } 1278 1279 return 0; 1280 } 1281 1282 /* 1283 * Generate or update blinding values, see section 10 of: 1284 * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, 1285 * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer 1286 * Berlin Heidelberg, 1996. p. 104-113. 1287 */ 1288 static int rsa_prepare_blinding(mbedtls_rsa_context *ctx, 1289 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) 1290 { 1291 int ret, count = 0; 1292 mbedtls_mpi R; 1293 1294 mbedtls_mpi_init(&R); 1295 1296 if (ctx->Vf.p != NULL) { 1297 /* We already have blinding values, just update them by squaring */ 1298 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &ctx->Vi)); 1299 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); 1300 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vf, &ctx->Vf)); 1301 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->N)); 1302 1303 goto cleanup; 1304 } 1305 1306 /* Unblinding value: Vf = random number, invertible mod N */ 1307 do { 1308 if (count++ > 10) { 1309 ret = MBEDTLS_ERR_RSA_RNG_FAILED; 1310 goto cleanup; 1311 } 1312 1313 MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&ctx->Vf, ctx->len - 1, f_rng, p_rng)); 1314 1315 /* Compute Vf^-1 as R * (R Vf)^-1 to avoid leaks from inv_mod. */ 1316 MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, ctx->len - 1, f_rng, p_rng)); 1317 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vf, &R)); 1318 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); 1319 1320 /* At this point, Vi is invertible mod N if and only if both Vf and R 1321 * are invertible mod N. If one of them isn't, we don't need to know 1322 * which one, we just loop and choose new values for both of them. 1323 * (Each iteration succeeds with overwhelming probability.) */ 1324 ret = mbedtls_mpi_inv_mod(&ctx->Vi, &ctx->Vi, &ctx->N); 1325 if (ret != 0 && ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) { 1326 goto cleanup; 1327 } 1328 1329 } while (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE); 1330 1331 /* Finish the computation of Vf^-1 = R * (R Vf)^-1 */ 1332 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &R)); 1333 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); 1334 1335 /* Blinding value: Vi = Vf^(-e) mod N 1336 * (Vi already contains Vf^-1 at this point) */ 1337 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN)); 1338 1339 1340 cleanup: 1341 mbedtls_mpi_free(&R); 1342 1343 return ret; 1344 } 1345 1346 /* 1347 * Unblind 1348 * T = T * Vf mod N 1349 */ 1350 static int rsa_unblind(mbedtls_mpi *T, mbedtls_mpi *Vf, const mbedtls_mpi *N) 1351 { 1352 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1353 const mbedtls_mpi_uint mm = mbedtls_mpi_core_montmul_init(N->p); 1354 const size_t nlimbs = N->n; 1355 const size_t tlimbs = mbedtls_mpi_core_montmul_working_limbs(nlimbs); 1356 mbedtls_mpi RR, M_T; 1357 1358 mbedtls_mpi_init(&RR); 1359 mbedtls_mpi_init(&M_T); 1360 1361 MBEDTLS_MPI_CHK(mbedtls_mpi_core_get_mont_r2_unsafe(&RR, N)); 1362 MBEDTLS_MPI_CHK(mbedtls_mpi_grow(&M_T, tlimbs)); 1363 1364 MBEDTLS_MPI_CHK(mbedtls_mpi_grow(T, nlimbs)); 1365 MBEDTLS_MPI_CHK(mbedtls_mpi_grow(Vf, nlimbs)); 1366 1367 /* T = T * Vf mod N 1368 * Reminder: montmul(A, B, N) = A * B * R^-1 mod N 1369 * Usually both operands are multiplied by R mod N beforehand (by calling 1370 * `to_mont_rep()` on them), yielding a result that's also * R mod N (aka 1371 * "in the Montgomery domain"). Here we only multiply one operand by R mod 1372 * N, so the result is directly what we want - no need to call 1373 * `from_mont_rep()` on it. */ 1374 mbedtls_mpi_core_to_mont_rep(T->p, T->p, N->p, nlimbs, mm, RR.p, M_T.p); 1375 mbedtls_mpi_core_montmul(T->p, T->p, Vf->p, nlimbs, N->p, nlimbs, mm, M_T.p); 1376 1377 cleanup: 1378 1379 mbedtls_mpi_free(&RR); 1380 mbedtls_mpi_free(&M_T); 1381 1382 return ret; 1383 } 1384 1385 /* 1386 * Exponent blinding supposed to prevent side-channel attacks using multiple 1387 * traces of measurements to recover the RSA key. The more collisions are there, 1388 * the more bits of the key can be recovered. See [3]. 1389 * 1390 * Collecting n collisions with m bit long blinding value requires 2^(m-m/n) 1391 * observations on average. 1392 * 1393 * For example with 28 byte blinding to achieve 2 collisions the adversary has 1394 * to make 2^112 observations on average. 1395 * 1396 * (With the currently (as of 2017 April) known best algorithms breaking 2048 1397 * bit RSA requires approximately as much time as trying out 2^112 random keys. 1398 * Thus in this sense with 28 byte blinding the security is not reduced by 1399 * side-channel attacks like the one in [3]) 1400 * 1401 * This countermeasure does not help if the key recovery is possible with a 1402 * single trace. 1403 */ 1404 #define RSA_EXPONENT_BLINDING 28 1405 1406 /* 1407 * Do an RSA private key operation 1408 */ 1409 int mbedtls_rsa_private(mbedtls_rsa_context *ctx, 1410 int (*f_rng)(void *, unsigned char *, size_t), 1411 void *p_rng, 1412 const unsigned char *input, 1413 unsigned char *output) 1414 { 1415 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1416 size_t olen; 1417 1418 /* Temporary holding the result */ 1419 mbedtls_mpi T; 1420 1421 /* Temporaries holding P-1, Q-1 and the 1422 * exponent blinding factor, respectively. */ 1423 mbedtls_mpi P1, Q1, R; 1424 1425 #if !defined(MBEDTLS_RSA_NO_CRT) 1426 /* Temporaries holding the results mod p resp. mod q. */ 1427 mbedtls_mpi TP, TQ; 1428 1429 /* Temporaries holding the blinded exponents for 1430 * the mod p resp. mod q computation (if used). */ 1431 mbedtls_mpi DP_blind, DQ_blind; 1432 #else 1433 /* Temporary holding the blinded exponent (if used). */ 1434 mbedtls_mpi D_blind; 1435 #endif /* MBEDTLS_RSA_NO_CRT */ 1436 1437 /* Temporaries holding the initial input and the double 1438 * checked result; should be the same in the end. */ 1439 mbedtls_mpi input_blinded, check_result_blinded; 1440 1441 if (f_rng == NULL) { 1442 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1443 } 1444 1445 if (rsa_check_context(ctx, 1 /* private key checks */, 1446 1 /* blinding on */) != 0) { 1447 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1448 } 1449 1450 #if defined(MBEDTLS_THREADING_C) 1451 if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { 1452 return ret; 1453 } 1454 #endif 1455 1456 /* MPI Initialization */ 1457 mbedtls_mpi_init(&T); 1458 1459 mbedtls_mpi_init(&P1); 1460 mbedtls_mpi_init(&Q1); 1461 mbedtls_mpi_init(&R); 1462 1463 #if defined(MBEDTLS_RSA_NO_CRT) 1464 mbedtls_mpi_init(&D_blind); 1465 #else 1466 mbedtls_mpi_init(&DP_blind); 1467 mbedtls_mpi_init(&DQ_blind); 1468 #endif 1469 1470 #if !defined(MBEDTLS_RSA_NO_CRT) 1471 mbedtls_mpi_init(&TP); mbedtls_mpi_init(&TQ); 1472 #endif 1473 1474 mbedtls_mpi_init(&input_blinded); 1475 mbedtls_mpi_init(&check_result_blinded); 1476 1477 /* End of MPI initialization */ 1478 1479 MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len)); 1480 if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) { 1481 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; 1482 goto cleanup; 1483 } 1484 1485 /* 1486 * Blinding 1487 * T = T * Vi mod N 1488 */ 1489 MBEDTLS_MPI_CHK(rsa_prepare_blinding(ctx, f_rng, p_rng)); 1490 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&T, &T, &ctx->Vi)); 1491 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &T, &ctx->N)); 1492 1493 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&input_blinded, &T)); 1494 1495 /* 1496 * Exponent blinding 1497 */ 1498 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&P1, &ctx->P, 1)); 1499 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&Q1, &ctx->Q, 1)); 1500 1501 #if defined(MBEDTLS_RSA_NO_CRT) 1502 /* 1503 * D_blind = ( P - 1 ) * ( Q - 1 ) * R + D 1504 */ 1505 MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, 1506 f_rng, p_rng)); 1507 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &P1, &Q1)); 1508 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &D_blind, &R)); 1509 MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&D_blind, &D_blind, &ctx->D)); 1510 #else 1511 /* 1512 * DP_blind = ( P - 1 ) * R + DP 1513 */ 1514 MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, 1515 f_rng, p_rng)); 1516 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DP_blind, &P1, &R)); 1517 MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DP_blind, &DP_blind, 1518 &ctx->DP)); 1519 1520 /* 1521 * DQ_blind = ( Q - 1 ) * R + DQ 1522 */ 1523 MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, 1524 f_rng, p_rng)); 1525 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DQ_blind, &Q1, &R)); 1526 MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DQ_blind, &DQ_blind, 1527 &ctx->DQ)); 1528 #endif /* MBEDTLS_RSA_NO_CRT */ 1529 1530 #if defined(MBEDTLS_RSA_NO_CRT) 1531 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&T, &T, &D_blind, &ctx->N, &ctx->RN)); 1532 #else 1533 /* 1534 * Faster decryption using the CRT 1535 * 1536 * TP = input ^ dP mod P 1537 * TQ = input ^ dQ mod Q 1538 */ 1539 1540 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TP, &T, &DP_blind, &ctx->P, &ctx->RP)); 1541 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TQ, &T, &DQ_blind, &ctx->Q, &ctx->RQ)); 1542 1543 /* 1544 * T = (TP - TQ) * (Q^-1 mod P) mod P 1545 */ 1546 MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&T, &TP, &TQ)); 1547 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->QP)); 1548 MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &TP, &ctx->P)); 1549 1550 /* 1551 * T = TQ + T * Q 1552 */ 1553 MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->Q)); 1554 MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&T, &TQ, &TP)); 1555 #endif /* MBEDTLS_RSA_NO_CRT */ 1556 1557 /* Verify the result to prevent glitching attacks. */ 1558 MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&check_result_blinded, &T, &ctx->E, 1559 &ctx->N, &ctx->RN)); 1560 if (mbedtls_mpi_cmp_mpi(&check_result_blinded, &input_blinded) != 0) { 1561 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; 1562 goto cleanup; 1563 } 1564 1565 /* 1566 * Unblind 1567 * T = T * Vf mod N 1568 */ 1569 MBEDTLS_MPI_CHK(rsa_unblind(&T, &ctx->Vf, &ctx->N)); 1570 1571 olen = ctx->len; 1572 MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen)); 1573 1574 cleanup: 1575 #if defined(MBEDTLS_THREADING_C) 1576 if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { 1577 return MBEDTLS_ERR_THREADING_MUTEX_ERROR; 1578 } 1579 #endif 1580 1581 mbedtls_mpi_free(&P1); 1582 mbedtls_mpi_free(&Q1); 1583 mbedtls_mpi_free(&R); 1584 1585 #if defined(MBEDTLS_RSA_NO_CRT) 1586 mbedtls_mpi_free(&D_blind); 1587 #else 1588 mbedtls_mpi_free(&DP_blind); 1589 mbedtls_mpi_free(&DQ_blind); 1590 #endif 1591 1592 mbedtls_mpi_free(&T); 1593 1594 #if !defined(MBEDTLS_RSA_NO_CRT) 1595 mbedtls_mpi_free(&TP); mbedtls_mpi_free(&TQ); 1596 #endif 1597 1598 mbedtls_mpi_free(&check_result_blinded); 1599 mbedtls_mpi_free(&input_blinded); 1600 1601 if (ret != 0 && ret >= -0x007f) { 1602 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret); 1603 } 1604 1605 return ret; 1606 } 1607 1608 #if defined(MBEDTLS_PKCS1_V21) 1609 /** 1610 * Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer. 1611 * 1612 * \param dst buffer to mask 1613 * \param dlen length of destination buffer 1614 * \param src source of the mask generation 1615 * \param slen length of the source buffer 1616 * \param md_alg message digest to use 1617 */ 1618 static int mgf_mask(unsigned char *dst, size_t dlen, unsigned char *src, 1619 size_t slen, mbedtls_md_type_t md_alg) 1620 { 1621 unsigned char counter[4]; 1622 unsigned char *p; 1623 unsigned int hlen; 1624 size_t i, use_len; 1625 unsigned char mask[MBEDTLS_MD_MAX_SIZE]; 1626 int ret = 0; 1627 const mbedtls_md_info_t *md_info; 1628 mbedtls_md_context_t md_ctx; 1629 1630 mbedtls_md_init(&md_ctx); 1631 md_info = mbedtls_md_info_from_type(md_alg); 1632 if (md_info == NULL) { 1633 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1634 } 1635 1636 mbedtls_md_init(&md_ctx); 1637 if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) { 1638 goto exit; 1639 } 1640 1641 hlen = mbedtls_md_get_size(md_info); 1642 1643 memset(mask, 0, sizeof(mask)); 1644 memset(counter, 0, 4); 1645 1646 /* Generate and apply dbMask */ 1647 p = dst; 1648 1649 while (dlen > 0) { 1650 use_len = hlen; 1651 if (dlen < hlen) { 1652 use_len = dlen; 1653 } 1654 1655 if ((ret = mbedtls_md_starts(&md_ctx)) != 0) { 1656 goto exit; 1657 } 1658 if ((ret = mbedtls_md_update(&md_ctx, src, slen)) != 0) { 1659 goto exit; 1660 } 1661 if ((ret = mbedtls_md_update(&md_ctx, counter, 4)) != 0) { 1662 goto exit; 1663 } 1664 if ((ret = mbedtls_md_finish(&md_ctx, mask)) != 0) { 1665 goto exit; 1666 } 1667 1668 for (i = 0; i < use_len; ++i) { 1669 *p++ ^= mask[i]; 1670 } 1671 1672 counter[3]++; 1673 1674 dlen -= use_len; 1675 } 1676 1677 exit: 1678 mbedtls_platform_zeroize(mask, sizeof(mask)); 1679 mbedtls_md_free(&md_ctx); 1680 1681 return ret; 1682 } 1683 1684 /** 1685 * Generate Hash(M') as in RFC 8017 page 43 points 5 and 6. 1686 * 1687 * \param hash the input hash 1688 * \param hlen length of the input hash 1689 * \param salt the input salt 1690 * \param slen length of the input salt 1691 * \param out the output buffer - must be large enough for \p md_alg 1692 * \param md_alg message digest to use 1693 */ 1694 static int hash_mprime(const unsigned char *hash, size_t hlen, 1695 const unsigned char *salt, size_t slen, 1696 unsigned char *out, mbedtls_md_type_t md_alg) 1697 { 1698 const unsigned char zeros[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; 1699 1700 mbedtls_md_context_t md_ctx; 1701 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1702 1703 const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(md_alg); 1704 if (md_info == NULL) { 1705 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1706 } 1707 1708 mbedtls_md_init(&md_ctx); 1709 if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) { 1710 goto exit; 1711 } 1712 if ((ret = mbedtls_md_starts(&md_ctx)) != 0) { 1713 goto exit; 1714 } 1715 if ((ret = mbedtls_md_update(&md_ctx, zeros, sizeof(zeros))) != 0) { 1716 goto exit; 1717 } 1718 if ((ret = mbedtls_md_update(&md_ctx, hash, hlen)) != 0) { 1719 goto exit; 1720 } 1721 if ((ret = mbedtls_md_update(&md_ctx, salt, slen)) != 0) { 1722 goto exit; 1723 } 1724 if ((ret = mbedtls_md_finish(&md_ctx, out)) != 0) { 1725 goto exit; 1726 } 1727 1728 exit: 1729 mbedtls_md_free(&md_ctx); 1730 1731 return ret; 1732 } 1733 1734 /** 1735 * Compute a hash. 1736 * 1737 * \param md_alg algorithm to use 1738 * \param input input message to hash 1739 * \param ilen input length 1740 * \param output the output buffer - must be large enough for \p md_alg 1741 */ 1742 static int compute_hash(mbedtls_md_type_t md_alg, 1743 const unsigned char *input, size_t ilen, 1744 unsigned char *output) 1745 { 1746 const mbedtls_md_info_t *md_info; 1747 1748 md_info = mbedtls_md_info_from_type(md_alg); 1749 if (md_info == NULL) { 1750 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1751 } 1752 1753 return mbedtls_md(md_info, input, ilen, output); 1754 } 1755 #endif /* MBEDTLS_PKCS1_V21 */ 1756 1757 #if defined(MBEDTLS_PKCS1_V21) 1758 /* 1759 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function 1760 */ 1761 int mbedtls_rsa_rsaes_oaep_encrypt(mbedtls_rsa_context *ctx, 1762 int (*f_rng)(void *, unsigned char *, size_t), 1763 void *p_rng, 1764 const unsigned char *label, size_t label_len, 1765 size_t ilen, 1766 const unsigned char *input, 1767 unsigned char *output) 1768 { 1769 size_t olen; 1770 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1771 unsigned char *p = output; 1772 unsigned int hlen; 1773 1774 if (f_rng == NULL) { 1775 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1776 } 1777 1778 hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id); 1779 if (hlen == 0) { 1780 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1781 } 1782 1783 olen = ctx->len; 1784 1785 /* first comparison checks for overflow */ 1786 if (ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2) { 1787 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1788 } 1789 1790 memset(output, 0, olen); 1791 1792 *p++ = 0; 1793 1794 /* Generate a random octet string seed */ 1795 if ((ret = f_rng(p_rng, p, hlen)) != 0) { 1796 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); 1797 } 1798 1799 p += hlen; 1800 1801 /* Construct DB */ 1802 ret = compute_hash((mbedtls_md_type_t) ctx->hash_id, label, label_len, p); 1803 if (ret != 0) { 1804 return ret; 1805 } 1806 p += hlen; 1807 p += olen - 2 * hlen - 2 - ilen; 1808 *p++ = 1; 1809 if (ilen != 0) { 1810 memcpy(p, input, ilen); 1811 } 1812 1813 /* maskedDB: Apply dbMask to DB */ 1814 if ((ret = mgf_mask(output + hlen + 1, olen - hlen - 1, output + 1, hlen, 1815 (mbedtls_md_type_t) ctx->hash_id)) != 0) { 1816 return ret; 1817 } 1818 1819 /* maskedSeed: Apply seedMask to seed */ 1820 if ((ret = mgf_mask(output + 1, hlen, output + hlen + 1, olen - hlen - 1, 1821 (mbedtls_md_type_t) ctx->hash_id)) != 0) { 1822 return ret; 1823 } 1824 1825 return mbedtls_rsa_public(ctx, output, output); 1826 } 1827 #endif /* MBEDTLS_PKCS1_V21 */ 1828 1829 #if defined(MBEDTLS_PKCS1_V15) 1830 /* 1831 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function 1832 */ 1833 int mbedtls_rsa_rsaes_pkcs1_v15_encrypt(mbedtls_rsa_context *ctx, 1834 int (*f_rng)(void *, unsigned char *, size_t), 1835 void *p_rng, size_t ilen, 1836 const unsigned char *input, 1837 unsigned char *output) 1838 { 1839 size_t nb_pad, olen; 1840 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1841 unsigned char *p = output; 1842 1843 olen = ctx->len; 1844 1845 /* first comparison checks for overflow */ 1846 if (ilen + 11 < ilen || olen < ilen + 11) { 1847 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1848 } 1849 1850 nb_pad = olen - 3 - ilen; 1851 1852 *p++ = 0; 1853 1854 if (f_rng == NULL) { 1855 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1856 } 1857 1858 *p++ = MBEDTLS_RSA_CRYPT; 1859 1860 while (nb_pad-- > 0) { 1861 int rng_dl = 100; 1862 1863 do { 1864 ret = f_rng(p_rng, p, 1); 1865 } while (*p == 0 && --rng_dl && ret == 0); 1866 1867 /* Check if RNG failed to generate data */ 1868 if (rng_dl == 0 || ret != 0) { 1869 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); 1870 } 1871 1872 p++; 1873 } 1874 1875 *p++ = 0; 1876 if (ilen != 0) { 1877 memcpy(p, input, ilen); 1878 } 1879 1880 return mbedtls_rsa_public(ctx, output, output); 1881 } 1882 #endif /* MBEDTLS_PKCS1_V15 */ 1883 1884 /* 1885 * Add the message padding, then do an RSA operation 1886 */ 1887 int mbedtls_rsa_pkcs1_encrypt(mbedtls_rsa_context *ctx, 1888 int (*f_rng)(void *, unsigned char *, size_t), 1889 void *p_rng, 1890 size_t ilen, 1891 const unsigned char *input, 1892 unsigned char *output) 1893 { 1894 switch (ctx->padding) { 1895 #if defined(MBEDTLS_PKCS1_V15) 1896 case MBEDTLS_RSA_PKCS_V15: 1897 return mbedtls_rsa_rsaes_pkcs1_v15_encrypt(ctx, f_rng, p_rng, 1898 ilen, input, output); 1899 #endif 1900 1901 #if defined(MBEDTLS_PKCS1_V21) 1902 case MBEDTLS_RSA_PKCS_V21: 1903 return mbedtls_rsa_rsaes_oaep_encrypt(ctx, f_rng, p_rng, NULL, 0, 1904 ilen, input, output); 1905 #endif 1906 1907 default: 1908 return MBEDTLS_ERR_RSA_INVALID_PADDING; 1909 } 1910 } 1911 1912 #if defined(MBEDTLS_PKCS1_V21) 1913 /* 1914 * Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function 1915 */ 1916 int mbedtls_rsa_rsaes_oaep_decrypt(mbedtls_rsa_context *ctx, 1917 int (*f_rng)(void *, unsigned char *, size_t), 1918 void *p_rng, 1919 const unsigned char *label, size_t label_len, 1920 size_t *olen, 1921 const unsigned char *input, 1922 unsigned char *output, 1923 size_t output_max_len) 1924 { 1925 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 1926 size_t ilen, i, pad_len; 1927 unsigned char *p; 1928 mbedtls_ct_condition_t bad, in_padding; 1929 unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; 1930 unsigned char lhash[MBEDTLS_MD_MAX_SIZE]; 1931 unsigned int hlen; 1932 1933 /* 1934 * Parameters sanity checks 1935 */ 1936 if (ctx->padding != MBEDTLS_RSA_PKCS_V21) { 1937 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1938 } 1939 1940 ilen = ctx->len; 1941 1942 if (ilen < 16 || ilen > sizeof(buf)) { 1943 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1944 } 1945 1946 hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id); 1947 if (hlen == 0) { 1948 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1949 } 1950 1951 // checking for integer underflow 1952 if (2 * hlen + 2 > ilen) { 1953 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 1954 } 1955 1956 /* 1957 * RSA operation 1958 */ 1959 ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf); 1960 1961 if (ret != 0) { 1962 goto cleanup; 1963 } 1964 1965 /* 1966 * Unmask data and generate lHash 1967 */ 1968 /* seed: Apply seedMask to maskedSeed */ 1969 if ((ret = mgf_mask(buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1, 1970 (mbedtls_md_type_t) ctx->hash_id)) != 0 || 1971 /* DB: Apply dbMask to maskedDB */ 1972 (ret = mgf_mask(buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen, 1973 (mbedtls_md_type_t) ctx->hash_id)) != 0) { 1974 goto cleanup; 1975 } 1976 1977 /* Generate lHash */ 1978 ret = compute_hash((mbedtls_md_type_t) ctx->hash_id, 1979 label, label_len, lhash); 1980 if (ret != 0) { 1981 goto cleanup; 1982 } 1983 1984 /* 1985 * Check contents, in "constant-time" 1986 */ 1987 p = buf; 1988 1989 bad = mbedtls_ct_bool(*p++); /* First byte must be 0 */ 1990 1991 p += hlen; /* Skip seed */ 1992 1993 /* Check lHash */ 1994 bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool(mbedtls_ct_memcmp(lhash, p, hlen))); 1995 p += hlen; 1996 1997 /* Get zero-padding len, but always read till end of buffer 1998 * (minus one, for the 01 byte) */ 1999 pad_len = 0; 2000 in_padding = MBEDTLS_CT_TRUE; 2001 for (i = 0; i < ilen - 2 * hlen - 2; i++) { 2002 in_padding = mbedtls_ct_bool_and(in_padding, mbedtls_ct_uint_eq(p[i], 0)); 2003 pad_len += mbedtls_ct_uint_if_else_0(in_padding, 1); 2004 } 2005 2006 p += pad_len; 2007 bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(*p++, 0x01)); 2008 2009 /* 2010 * The only information "leaked" is whether the padding was correct or not 2011 * (eg, no data is copied if it was not correct). This meets the 2012 * recommendations in PKCS#1 v2.2: an opponent cannot distinguish between 2013 * the different error conditions. 2014 */ 2015 if (bad != MBEDTLS_CT_FALSE) { 2016 ret = MBEDTLS_ERR_RSA_INVALID_PADDING; 2017 goto cleanup; 2018 } 2019 2020 if (ilen - ((size_t) (p - buf)) > output_max_len) { 2021 ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE; 2022 goto cleanup; 2023 } 2024 2025 *olen = ilen - ((size_t) (p - buf)); 2026 if (*olen != 0) { 2027 memcpy(output, p, *olen); 2028 } 2029 ret = 0; 2030 2031 cleanup: 2032 mbedtls_platform_zeroize(buf, sizeof(buf)); 2033 mbedtls_platform_zeroize(lhash, sizeof(lhash)); 2034 2035 return ret; 2036 } 2037 #endif /* MBEDTLS_PKCS1_V21 */ 2038 2039 #if defined(MBEDTLS_PKCS1_V15) 2040 /* 2041 * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function 2042 */ 2043 int mbedtls_rsa_rsaes_pkcs1_v15_decrypt(mbedtls_rsa_context *ctx, 2044 int (*f_rng)(void *, unsigned char *, size_t), 2045 void *p_rng, 2046 size_t *olen, 2047 const unsigned char *input, 2048 unsigned char *output, 2049 size_t output_max_len) 2050 { 2051 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2052 size_t ilen; 2053 unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; 2054 2055 ilen = ctx->len; 2056 2057 if (ctx->padding != MBEDTLS_RSA_PKCS_V15) { 2058 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2059 } 2060 2061 if (ilen < 16 || ilen > sizeof(buf)) { 2062 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2063 } 2064 2065 ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf); 2066 2067 if (ret != 0) { 2068 goto cleanup; 2069 } 2070 2071 ret = mbedtls_ct_rsaes_pkcs1_v15_unpadding(buf, ilen, 2072 output, output_max_len, olen); 2073 2074 cleanup: 2075 mbedtls_platform_zeroize(buf, sizeof(buf)); 2076 2077 return ret; 2078 } 2079 #endif /* MBEDTLS_PKCS1_V15 */ 2080 2081 /* 2082 * Do an RSA operation, then remove the message padding 2083 */ 2084 int mbedtls_rsa_pkcs1_decrypt(mbedtls_rsa_context *ctx, 2085 int (*f_rng)(void *, unsigned char *, size_t), 2086 void *p_rng, 2087 size_t *olen, 2088 const unsigned char *input, 2089 unsigned char *output, 2090 size_t output_max_len) 2091 { 2092 switch (ctx->padding) { 2093 #if defined(MBEDTLS_PKCS1_V15) 2094 case MBEDTLS_RSA_PKCS_V15: 2095 return mbedtls_rsa_rsaes_pkcs1_v15_decrypt(ctx, f_rng, p_rng, olen, 2096 input, output, output_max_len); 2097 #endif 2098 2099 #if defined(MBEDTLS_PKCS1_V21) 2100 case MBEDTLS_RSA_PKCS_V21: 2101 return mbedtls_rsa_rsaes_oaep_decrypt(ctx, f_rng, p_rng, NULL, 0, 2102 olen, input, output, 2103 output_max_len); 2104 #endif 2105 2106 default: 2107 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2108 } 2109 } 2110 2111 #if defined(MBEDTLS_PKCS1_V21) 2112 static int rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx, 2113 int (*f_rng)(void *, unsigned char *, size_t), 2114 void *p_rng, 2115 mbedtls_md_type_t md_alg, 2116 unsigned int hashlen, 2117 const unsigned char *hash, 2118 int saltlen, 2119 unsigned char *sig) 2120 { 2121 size_t olen; 2122 unsigned char *p = sig; 2123 unsigned char *salt = NULL; 2124 size_t slen, min_slen, hlen, offset = 0; 2125 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2126 size_t msb; 2127 mbedtls_md_type_t hash_id; 2128 2129 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2130 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2131 } 2132 2133 if (f_rng == NULL) { 2134 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2135 } 2136 2137 olen = ctx->len; 2138 2139 if (md_alg != MBEDTLS_MD_NONE) { 2140 /* Gather length of hash to sign */ 2141 size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg); 2142 if (exp_hashlen == 0) { 2143 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2144 } 2145 2146 if (hashlen != exp_hashlen) { 2147 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2148 } 2149 } 2150 2151 hash_id = (mbedtls_md_type_t) ctx->hash_id; 2152 if (hash_id == MBEDTLS_MD_NONE) { 2153 hash_id = md_alg; 2154 } 2155 hlen = mbedtls_md_get_size_from_type(hash_id); 2156 if (hlen == 0) { 2157 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2158 } 2159 2160 if (saltlen == MBEDTLS_RSA_SALT_LEN_ANY) { 2161 /* Calculate the largest possible salt length, up to the hash size. 2162 * Normally this is the hash length, which is the maximum salt length 2163 * according to FIPS 185-4 §5.5 (e) and common practice. If there is not 2164 * enough room, use the maximum salt length that fits. The constraint is 2165 * that the hash length plus the salt length plus 2 bytes must be at most 2166 * the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017 2167 * (PKCS#1 v2.2) §9.1.1 step 3. */ 2168 min_slen = hlen - 2; 2169 if (olen < hlen + min_slen + 2) { 2170 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2171 } else if (olen >= hlen + hlen + 2) { 2172 slen = hlen; 2173 } else { 2174 slen = olen - hlen - 2; 2175 } 2176 } else if ((saltlen < 0) || (saltlen + hlen + 2 > olen)) { 2177 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2178 } else { 2179 slen = (size_t) saltlen; 2180 } 2181 2182 memset(sig, 0, olen); 2183 2184 /* Note: EMSA-PSS encoding is over the length of N - 1 bits */ 2185 msb = mbedtls_mpi_bitlen(&ctx->N) - 1; 2186 p += olen - hlen - slen - 2; 2187 *p++ = 0x01; 2188 2189 /* Generate salt of length slen in place in the encoded message */ 2190 salt = p; 2191 if ((ret = f_rng(p_rng, salt, slen)) != 0) { 2192 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); 2193 } 2194 2195 p += slen; 2196 2197 /* Generate H = Hash( M' ) */ 2198 ret = hash_mprime(hash, hashlen, salt, slen, p, hash_id); 2199 if (ret != 0) { 2200 return ret; 2201 } 2202 2203 /* Compensate for boundary condition when applying mask */ 2204 if (msb % 8 == 0) { 2205 offset = 1; 2206 } 2207 2208 /* maskedDB: Apply dbMask to DB */ 2209 ret = mgf_mask(sig + offset, olen - hlen - 1 - offset, p, hlen, hash_id); 2210 if (ret != 0) { 2211 return ret; 2212 } 2213 2214 msb = mbedtls_mpi_bitlen(&ctx->N) - 1; 2215 sig[0] &= 0xFF >> (olen * 8 - msb); 2216 2217 p += hlen; 2218 *p++ = 0xBC; 2219 2220 return mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig); 2221 } 2222 2223 static int rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx, 2224 int (*f_rng)(void *, unsigned char *, size_t), 2225 void *p_rng, 2226 mbedtls_md_type_t md_alg, 2227 unsigned int hashlen, 2228 const unsigned char *hash, 2229 int saltlen, 2230 unsigned char *sig) 2231 { 2232 if (ctx->padding != MBEDTLS_RSA_PKCS_V21) { 2233 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2234 } 2235 if ((ctx->hash_id == MBEDTLS_MD_NONE) && (md_alg == MBEDTLS_MD_NONE)) { 2236 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2237 } 2238 return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg, hashlen, hash, saltlen, 2239 sig); 2240 } 2241 2242 int mbedtls_rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx, 2243 int (*f_rng)(void *, unsigned char *, size_t), 2244 void *p_rng, 2245 mbedtls_md_type_t md_alg, 2246 unsigned int hashlen, 2247 const unsigned char *hash, 2248 unsigned char *sig) 2249 { 2250 return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg, 2251 hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig); 2252 } 2253 2254 /* 2255 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function with 2256 * the option to pass in the salt length. 2257 */ 2258 int mbedtls_rsa_rsassa_pss_sign_ext(mbedtls_rsa_context *ctx, 2259 int (*f_rng)(void *, unsigned char *, size_t), 2260 void *p_rng, 2261 mbedtls_md_type_t md_alg, 2262 unsigned int hashlen, 2263 const unsigned char *hash, 2264 int saltlen, 2265 unsigned char *sig) 2266 { 2267 return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, 2268 hashlen, hash, saltlen, sig); 2269 } 2270 2271 /* 2272 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function 2273 */ 2274 int mbedtls_rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx, 2275 int (*f_rng)(void *, unsigned char *, size_t), 2276 void *p_rng, 2277 mbedtls_md_type_t md_alg, 2278 unsigned int hashlen, 2279 const unsigned char *hash, 2280 unsigned char *sig) 2281 { 2282 return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, 2283 hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig); 2284 } 2285 #endif /* MBEDTLS_PKCS1_V21 */ 2286 2287 #if defined(MBEDTLS_PKCS1_V15) 2288 /* 2289 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function 2290 */ 2291 2292 /* Construct a PKCS v1.5 encoding of a hashed message 2293 * 2294 * This is used both for signature generation and verification. 2295 * 2296 * Parameters: 2297 * - md_alg: Identifies the hash algorithm used to generate the given hash; 2298 * MBEDTLS_MD_NONE if raw data is signed. 2299 * - hashlen: Length of hash. Must match md_alg if that's not NONE. 2300 * - hash: Buffer containing the hashed message or the raw data. 2301 * - dst_len: Length of the encoded message. 2302 * - dst: Buffer to hold the encoded message. 2303 * 2304 * Assumptions: 2305 * - hash has size hashlen. 2306 * - dst points to a buffer of size at least dst_len. 2307 * 2308 */ 2309 static int rsa_rsassa_pkcs1_v15_encode(mbedtls_md_type_t md_alg, 2310 unsigned int hashlen, 2311 const unsigned char *hash, 2312 size_t dst_len, 2313 unsigned char *dst) 2314 { 2315 size_t oid_size = 0; 2316 size_t nb_pad = dst_len; 2317 unsigned char *p = dst; 2318 const char *oid = NULL; 2319 2320 /* Are we signing hashed or raw data? */ 2321 if (md_alg != MBEDTLS_MD_NONE) { 2322 unsigned char md_size = mbedtls_md_get_size_from_type(md_alg); 2323 if (md_size == 0) { 2324 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2325 } 2326 2327 if (mbedtls_oid_get_oid_by_md(md_alg, &oid, &oid_size) != 0) { 2328 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2329 } 2330 2331 if (hashlen != md_size) { 2332 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2333 } 2334 2335 /* Double-check that 8 + hashlen + oid_size can be used as a 2336 * 1-byte ASN.1 length encoding and that there's no overflow. */ 2337 if (8 + hashlen + oid_size >= 0x80 || 2338 10 + hashlen < hashlen || 2339 10 + hashlen + oid_size < 10 + hashlen) { 2340 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2341 } 2342 2343 /* 2344 * Static bounds check: 2345 * - Need 10 bytes for five tag-length pairs. 2346 * (Insist on 1-byte length encodings to protect against variants of 2347 * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification) 2348 * - Need hashlen bytes for hash 2349 * - Need oid_size bytes for hash alg OID. 2350 */ 2351 if (nb_pad < 10 + hashlen + oid_size) { 2352 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2353 } 2354 nb_pad -= 10 + hashlen + oid_size; 2355 } else { 2356 if (nb_pad < hashlen) { 2357 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2358 } 2359 2360 nb_pad -= hashlen; 2361 } 2362 2363 /* Need space for signature header and padding delimiter (3 bytes), 2364 * and 8 bytes for the minimal padding */ 2365 if (nb_pad < 3 + 8) { 2366 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2367 } 2368 nb_pad -= 3; 2369 2370 /* Now nb_pad is the amount of memory to be filled 2371 * with padding, and at least 8 bytes long. */ 2372 2373 /* Write signature header and padding */ 2374 *p++ = 0; 2375 *p++ = MBEDTLS_RSA_SIGN; 2376 memset(p, 0xFF, nb_pad); 2377 p += nb_pad; 2378 *p++ = 0; 2379 2380 /* Are we signing raw data? */ 2381 if (md_alg == MBEDTLS_MD_NONE) { 2382 memcpy(p, hash, hashlen); 2383 return 0; 2384 } 2385 2386 /* Signing hashed data, add corresponding ASN.1 structure 2387 * 2388 * DigestInfo ::= SEQUENCE { 2389 * digestAlgorithm DigestAlgorithmIdentifier, 2390 * digest Digest } 2391 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier 2392 * Digest ::= OCTET STRING 2393 * 2394 * Schematic: 2395 * TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ] 2396 * TAG-NULL + LEN [ NULL ] ] 2397 * TAG-OCTET + LEN [ HASH ] ] 2398 */ 2399 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; 2400 *p++ = (unsigned char) (0x08 + oid_size + hashlen); 2401 *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; 2402 *p++ = (unsigned char) (0x04 + oid_size); 2403 *p++ = MBEDTLS_ASN1_OID; 2404 *p++ = (unsigned char) oid_size; 2405 memcpy(p, oid, oid_size); 2406 p += oid_size; 2407 *p++ = MBEDTLS_ASN1_NULL; 2408 *p++ = 0x00; 2409 *p++ = MBEDTLS_ASN1_OCTET_STRING; 2410 *p++ = (unsigned char) hashlen; 2411 memcpy(p, hash, hashlen); 2412 p += hashlen; 2413 2414 /* Just a sanity-check, should be automatic 2415 * after the initial bounds check. */ 2416 if (p != dst + dst_len) { 2417 mbedtls_platform_zeroize(dst, dst_len); 2418 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2419 } 2420 2421 return 0; 2422 } 2423 2424 /* 2425 * Do an RSA operation to sign the message digest 2426 */ 2427 int mbedtls_rsa_rsassa_pkcs1_v15_sign(mbedtls_rsa_context *ctx, 2428 int (*f_rng)(void *, unsigned char *, size_t), 2429 void *p_rng, 2430 mbedtls_md_type_t md_alg, 2431 unsigned int hashlen, 2432 const unsigned char *hash, 2433 unsigned char *sig) 2434 { 2435 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2436 unsigned char *sig_try = NULL, *verif = NULL; 2437 2438 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2439 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2440 } 2441 2442 if (ctx->padding != MBEDTLS_RSA_PKCS_V15) { 2443 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2444 } 2445 2446 /* 2447 * Prepare PKCS1-v1.5 encoding (padding and hash identifier) 2448 */ 2449 2450 if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash, 2451 ctx->len, sig)) != 0) { 2452 return ret; 2453 } 2454 2455 /* Private key operation 2456 * 2457 * In order to prevent Lenstra's attack, make the signature in a 2458 * temporary buffer and check it before returning it. 2459 */ 2460 2461 sig_try = mbedtls_calloc(1, ctx->len); 2462 if (sig_try == NULL) { 2463 return MBEDTLS_ERR_MPI_ALLOC_FAILED; 2464 } 2465 2466 verif = mbedtls_calloc(1, ctx->len); 2467 if (verif == NULL) { 2468 mbedtls_free(sig_try); 2469 return MBEDTLS_ERR_MPI_ALLOC_FAILED; 2470 } 2471 2472 MBEDTLS_MPI_CHK(mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig_try)); 2473 MBEDTLS_MPI_CHK(mbedtls_rsa_public(ctx, sig_try, verif)); 2474 2475 if (mbedtls_ct_memcmp(verif, sig, ctx->len) != 0) { 2476 ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED; 2477 goto cleanup; 2478 } 2479 2480 memcpy(sig, sig_try, ctx->len); 2481 2482 cleanup: 2483 mbedtls_zeroize_and_free(sig_try, ctx->len); 2484 mbedtls_zeroize_and_free(verif, ctx->len); 2485 2486 if (ret != 0) { 2487 memset(sig, '!', ctx->len); 2488 } 2489 return ret; 2490 } 2491 #endif /* MBEDTLS_PKCS1_V15 */ 2492 2493 /* 2494 * Do an RSA operation to sign the message digest 2495 */ 2496 int mbedtls_rsa_pkcs1_sign(mbedtls_rsa_context *ctx, 2497 int (*f_rng)(void *, unsigned char *, size_t), 2498 void *p_rng, 2499 mbedtls_md_type_t md_alg, 2500 unsigned int hashlen, 2501 const unsigned char *hash, 2502 unsigned char *sig) 2503 { 2504 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2505 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2506 } 2507 2508 switch (ctx->padding) { 2509 #if defined(MBEDTLS_PKCS1_V15) 2510 case MBEDTLS_RSA_PKCS_V15: 2511 return mbedtls_rsa_rsassa_pkcs1_v15_sign(ctx, f_rng, p_rng, 2512 md_alg, hashlen, hash, sig); 2513 #endif 2514 2515 #if defined(MBEDTLS_PKCS1_V21) 2516 case MBEDTLS_RSA_PKCS_V21: 2517 return mbedtls_rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, 2518 hashlen, hash, sig); 2519 #endif 2520 2521 default: 2522 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2523 } 2524 } 2525 2526 #if defined(MBEDTLS_PKCS1_V21) 2527 /* 2528 * Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function 2529 */ 2530 int mbedtls_rsa_rsassa_pss_verify_ext(mbedtls_rsa_context *ctx, 2531 mbedtls_md_type_t md_alg, 2532 unsigned int hashlen, 2533 const unsigned char *hash, 2534 mbedtls_md_type_t mgf1_hash_id, 2535 int expected_salt_len, 2536 const unsigned char *sig) 2537 { 2538 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2539 size_t siglen; 2540 unsigned char *p; 2541 unsigned char *hash_start; 2542 unsigned char result[MBEDTLS_MD_MAX_SIZE]; 2543 unsigned int hlen; 2544 size_t observed_salt_len, msb; 2545 unsigned char buf[MBEDTLS_MPI_MAX_SIZE] = { 0 }; 2546 2547 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2548 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2549 } 2550 2551 siglen = ctx->len; 2552 2553 if (siglen < 16 || siglen > sizeof(buf)) { 2554 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2555 } 2556 2557 ret = mbedtls_rsa_public(ctx, sig, buf); 2558 2559 if (ret != 0) { 2560 return ret; 2561 } 2562 2563 p = buf; 2564 2565 if (buf[siglen - 1] != 0xBC) { 2566 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2567 } 2568 2569 if (md_alg != MBEDTLS_MD_NONE) { 2570 /* Gather length of hash to sign */ 2571 size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg); 2572 if (exp_hashlen == 0) { 2573 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2574 } 2575 2576 if (hashlen != exp_hashlen) { 2577 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2578 } 2579 } 2580 2581 hlen = mbedtls_md_get_size_from_type(mgf1_hash_id); 2582 if (hlen == 0) { 2583 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2584 } 2585 2586 /* 2587 * Note: EMSA-PSS verification is over the length of N - 1 bits 2588 */ 2589 msb = mbedtls_mpi_bitlen(&ctx->N) - 1; 2590 2591 if (buf[0] >> (8 - siglen * 8 + msb)) { 2592 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2593 } 2594 2595 /* Compensate for boundary condition when applying mask */ 2596 if (msb % 8 == 0) { 2597 p++; 2598 siglen -= 1; 2599 } 2600 2601 if (siglen < hlen + 2) { 2602 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2603 } 2604 hash_start = p + siglen - hlen - 1; 2605 2606 ret = mgf_mask(p, siglen - hlen - 1, hash_start, hlen, mgf1_hash_id); 2607 if (ret != 0) { 2608 return ret; 2609 } 2610 2611 buf[0] &= 0xFF >> (siglen * 8 - msb); 2612 2613 while (p < hash_start - 1 && *p == 0) { 2614 p++; 2615 } 2616 2617 if (*p++ != 0x01) { 2618 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2619 } 2620 2621 observed_salt_len = (size_t) (hash_start - p); 2622 2623 if (expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY && 2624 observed_salt_len != (size_t) expected_salt_len) { 2625 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2626 } 2627 2628 /* 2629 * Generate H = Hash( M' ) 2630 */ 2631 ret = hash_mprime(hash, hashlen, p, observed_salt_len, 2632 result, mgf1_hash_id); 2633 if (ret != 0) { 2634 return ret; 2635 } 2636 2637 if (memcmp(hash_start, result, hlen) != 0) { 2638 return MBEDTLS_ERR_RSA_VERIFY_FAILED; 2639 } 2640 2641 return 0; 2642 } 2643 2644 /* 2645 * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function 2646 */ 2647 int mbedtls_rsa_rsassa_pss_verify(mbedtls_rsa_context *ctx, 2648 mbedtls_md_type_t md_alg, 2649 unsigned int hashlen, 2650 const unsigned char *hash, 2651 const unsigned char *sig) 2652 { 2653 mbedtls_md_type_t mgf1_hash_id; 2654 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2655 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2656 } 2657 2658 mgf1_hash_id = (ctx->hash_id != MBEDTLS_MD_NONE) 2659 ? (mbedtls_md_type_t) ctx->hash_id 2660 : md_alg; 2661 2662 return mbedtls_rsa_rsassa_pss_verify_ext(ctx, 2663 md_alg, hashlen, hash, 2664 mgf1_hash_id, 2665 MBEDTLS_RSA_SALT_LEN_ANY, 2666 sig); 2667 2668 } 2669 #endif /* MBEDTLS_PKCS1_V21 */ 2670 2671 #if defined(MBEDTLS_PKCS1_V15) 2672 /* 2673 * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function 2674 */ 2675 int mbedtls_rsa_rsassa_pkcs1_v15_verify(mbedtls_rsa_context *ctx, 2676 mbedtls_md_type_t md_alg, 2677 unsigned int hashlen, 2678 const unsigned char *hash, 2679 const unsigned char *sig) 2680 { 2681 int ret = 0; 2682 size_t sig_len; 2683 unsigned char *encoded = NULL, *encoded_expected = NULL; 2684 2685 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2686 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2687 } 2688 2689 sig_len = ctx->len; 2690 2691 /* 2692 * Prepare expected PKCS1 v1.5 encoding of hash. 2693 */ 2694 2695 if ((encoded = mbedtls_calloc(1, sig_len)) == NULL || 2696 (encoded_expected = mbedtls_calloc(1, sig_len)) == NULL) { 2697 ret = MBEDTLS_ERR_MPI_ALLOC_FAILED; 2698 goto cleanup; 2699 } 2700 2701 if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash, sig_len, 2702 encoded_expected)) != 0) { 2703 goto cleanup; 2704 } 2705 2706 /* 2707 * Apply RSA primitive to get what should be PKCS1 encoded hash. 2708 */ 2709 2710 ret = mbedtls_rsa_public(ctx, sig, encoded); 2711 if (ret != 0) { 2712 goto cleanup; 2713 } 2714 2715 /* 2716 * Compare 2717 */ 2718 2719 if ((ret = mbedtls_ct_memcmp(encoded, encoded_expected, 2720 sig_len)) != 0) { 2721 ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; 2722 goto cleanup; 2723 } 2724 2725 cleanup: 2726 2727 if (encoded != NULL) { 2728 mbedtls_zeroize_and_free(encoded, sig_len); 2729 } 2730 2731 if (encoded_expected != NULL) { 2732 mbedtls_zeroize_and_free(encoded_expected, sig_len); 2733 } 2734 2735 return ret; 2736 } 2737 #endif /* MBEDTLS_PKCS1_V15 */ 2738 2739 /* 2740 * Do an RSA operation and check the message digest 2741 */ 2742 int mbedtls_rsa_pkcs1_verify(mbedtls_rsa_context *ctx, 2743 mbedtls_md_type_t md_alg, 2744 unsigned int hashlen, 2745 const unsigned char *hash, 2746 const unsigned char *sig) 2747 { 2748 if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { 2749 return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; 2750 } 2751 2752 switch (ctx->padding) { 2753 #if defined(MBEDTLS_PKCS1_V15) 2754 case MBEDTLS_RSA_PKCS_V15: 2755 return mbedtls_rsa_rsassa_pkcs1_v15_verify(ctx, md_alg, 2756 hashlen, hash, sig); 2757 #endif 2758 2759 #if defined(MBEDTLS_PKCS1_V21) 2760 case MBEDTLS_RSA_PKCS_V21: 2761 return mbedtls_rsa_rsassa_pss_verify(ctx, md_alg, 2762 hashlen, hash, sig); 2763 #endif 2764 2765 default: 2766 return MBEDTLS_ERR_RSA_INVALID_PADDING; 2767 } 2768 } 2769 2770 /* 2771 * Copy the components of an RSA key 2772 */ 2773 int mbedtls_rsa_copy(mbedtls_rsa_context *dst, const mbedtls_rsa_context *src) 2774 { 2775 int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; 2776 2777 dst->len = src->len; 2778 2779 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->N, &src->N)); 2780 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->E, &src->E)); 2781 2782 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->D, &src->D)); 2783 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->P, &src->P)); 2784 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Q, &src->Q)); 2785 2786 #if !defined(MBEDTLS_RSA_NO_CRT) 2787 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DP, &src->DP)); 2788 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DQ, &src->DQ)); 2789 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->QP, &src->QP)); 2790 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RP, &src->RP)); 2791 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RQ, &src->RQ)); 2792 #endif 2793 2794 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RN, &src->RN)); 2795 2796 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vi, &src->Vi)); 2797 MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vf, &src->Vf)); 2798 2799 dst->padding = src->padding; 2800 dst->hash_id = src->hash_id; 2801 2802 cleanup: 2803 if (ret != 0) { 2804 mbedtls_rsa_free(dst); 2805 } 2806 2807 return ret; 2808 } 2809 2810 /* 2811 * Free the components of an RSA key 2812 */ 2813 void mbedtls_rsa_free(mbedtls_rsa_context *ctx) 2814 { 2815 if (ctx == NULL) { 2816 return; 2817 } 2818 2819 mbedtls_mpi_free(&ctx->Vi); 2820 mbedtls_mpi_free(&ctx->Vf); 2821 mbedtls_mpi_free(&ctx->RN); 2822 mbedtls_mpi_free(&ctx->D); 2823 mbedtls_mpi_free(&ctx->Q); 2824 mbedtls_mpi_free(&ctx->P); 2825 mbedtls_mpi_free(&ctx->E); 2826 mbedtls_mpi_free(&ctx->N); 2827 2828 #if !defined(MBEDTLS_RSA_NO_CRT) 2829 mbedtls_mpi_free(&ctx->RQ); 2830 mbedtls_mpi_free(&ctx->RP); 2831 mbedtls_mpi_free(&ctx->QP); 2832 mbedtls_mpi_free(&ctx->DQ); 2833 mbedtls_mpi_free(&ctx->DP); 2834 #endif /* MBEDTLS_RSA_NO_CRT */ 2835 2836 #if defined(MBEDTLS_THREADING_C) 2837 /* Free the mutex, but only if it hasn't been freed already. */ 2838 if (ctx->ver != 0) { 2839 mbedtls_mutex_free(&ctx->mutex); 2840 ctx->ver = 0; 2841 } 2842 #endif 2843 } 2844 2845 #endif /* !MBEDTLS_RSA_ALT */ 2846 2847 #if defined(MBEDTLS_SELF_TEST) 2848 2849 2850 /* 2851 * Example RSA-1024 keypair, for test purposes 2852 */ 2853 #define KEY_LEN 128 2854 2855 #define RSA_N "9292758453063D803DD603D5E777D788" \ 2856 "8ED1D5BF35786190FA2F23EBC0848AEA" \ 2857 "DDA92CA6C3D80B32C4D109BE0F36D6AE" \ 2858 "7130B9CED7ACDF54CFC7555AC14EEBAB" \ 2859 "93A89813FBF3C4F8066D2D800F7C38A8" \ 2860 "1AE31942917403FF4946B0A83D3D3E05" \ 2861 "EE57C6F5F5606FB5D4BC6CD34EE0801A" \ 2862 "5E94BB77B07507233A0BC7BAC8F90F79" 2863 2864 #define RSA_E "10001" 2865 2866 #define RSA_D "24BF6185468786FDD303083D25E64EFC" \ 2867 "66CA472BC44D253102F8B4A9D3BFA750" \ 2868 "91386C0077937FE33FA3252D28855837" \ 2869 "AE1B484A8A9A45F7EE8C0C634F99E8CD" \ 2870 "DF79C5CE07EE72C7F123142198164234" \ 2871 "CABB724CF78B8173B9F880FC86322407" \ 2872 "AF1FEDFDDE2BEB674CA15F3E81A1521E" \ 2873 "071513A1E85B5DFA031F21ECAE91A34D" 2874 2875 #define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \ 2876 "2C01CAD19EA484A87EA4377637E75500" \ 2877 "FCB2005C5C7DD6EC4AC023CDA285D796" \ 2878 "C3D9E75E1EFC42488BB4F1D13AC30A57" 2879 2880 #define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \ 2881 "E211C2B9E5DB1ED0BF61D0D9899620F4" \ 2882 "910E4168387E3C30AA1E00C339A79508" \ 2883 "8452DD96A9A5EA5D9DCA68DA636032AF" 2884 2885 #define PT_LEN 24 2886 #define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \ 2887 "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD" 2888 2889 #if defined(MBEDTLS_PKCS1_V15) 2890 static int myrand(void *rng_state, unsigned char *output, size_t len) 2891 { 2892 #if !defined(__OpenBSD__) && !defined(__NetBSD__) 2893 size_t i; 2894 2895 if (rng_state != NULL) { 2896 rng_state = NULL; 2897 } 2898 2899 for (i = 0; i < len; ++i) { 2900 output[i] = rand(); 2901 } 2902 #else 2903 if (rng_state != NULL) { 2904 rng_state = NULL; 2905 } 2906 2907 arc4random_buf(output, len); 2908 #endif /* !OpenBSD && !NetBSD */ 2909 2910 return 0; 2911 } 2912 #endif /* MBEDTLS_PKCS1_V15 */ 2913 2914 /* 2915 * Checkup routine 2916 */ 2917 int mbedtls_rsa_self_test(int verbose) 2918 { 2919 int ret = 0; 2920 #if defined(MBEDTLS_PKCS1_V15) 2921 size_t len; 2922 mbedtls_rsa_context rsa; 2923 unsigned char rsa_plaintext[PT_LEN]; 2924 unsigned char rsa_decrypted[PT_LEN]; 2925 unsigned char rsa_ciphertext[KEY_LEN]; 2926 #if defined(MBEDTLS_MD_CAN_SHA1) 2927 unsigned char sha1sum[20]; 2928 #endif 2929 2930 mbedtls_mpi K; 2931 2932 mbedtls_mpi_init(&K); 2933 mbedtls_rsa_init(&rsa); 2934 2935 MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_N)); 2936 MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, &K, NULL, NULL, NULL, NULL)); 2937 MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_P)); 2938 MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, &K, NULL, NULL, NULL)); 2939 MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_Q)); 2940 MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, &K, NULL, NULL)); 2941 MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_D)); 2942 MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, &K, NULL)); 2943 MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_E)); 2944 MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, NULL, &K)); 2945 2946 MBEDTLS_MPI_CHK(mbedtls_rsa_complete(&rsa)); 2947 2948 if (verbose != 0) { 2949 mbedtls_printf(" RSA key validation: "); 2950 } 2951 2952 if (mbedtls_rsa_check_pubkey(&rsa) != 0 || 2953 mbedtls_rsa_check_privkey(&rsa) != 0) { 2954 if (verbose != 0) { 2955 mbedtls_printf("failed\n"); 2956 } 2957 2958 ret = 1; 2959 goto cleanup; 2960 } 2961 2962 if (verbose != 0) { 2963 mbedtls_printf("passed\n PKCS#1 encryption : "); 2964 } 2965 2966 memcpy(rsa_plaintext, RSA_PT, PT_LEN); 2967 2968 if (mbedtls_rsa_pkcs1_encrypt(&rsa, myrand, NULL, 2969 PT_LEN, rsa_plaintext, 2970 rsa_ciphertext) != 0) { 2971 if (verbose != 0) { 2972 mbedtls_printf("failed\n"); 2973 } 2974 2975 ret = 1; 2976 goto cleanup; 2977 } 2978 2979 if (verbose != 0) { 2980 mbedtls_printf("passed\n PKCS#1 decryption : "); 2981 } 2982 2983 if (mbedtls_rsa_pkcs1_decrypt(&rsa, myrand, NULL, 2984 &len, rsa_ciphertext, rsa_decrypted, 2985 sizeof(rsa_decrypted)) != 0) { 2986 if (verbose != 0) { 2987 mbedtls_printf("failed\n"); 2988 } 2989 2990 ret = 1; 2991 goto cleanup; 2992 } 2993 2994 if (memcmp(rsa_decrypted, rsa_plaintext, len) != 0) { 2995 if (verbose != 0) { 2996 mbedtls_printf("failed\n"); 2997 } 2998 2999 ret = 1; 3000 goto cleanup; 3001 } 3002 3003 if (verbose != 0) { 3004 mbedtls_printf("passed\n"); 3005 } 3006 3007 #if defined(MBEDTLS_MD_CAN_SHA1) 3008 if (verbose != 0) { 3009 mbedtls_printf(" PKCS#1 data sign : "); 3010 } 3011 3012 if (mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA1), 3013 rsa_plaintext, PT_LEN, sha1sum) != 0) { 3014 if (verbose != 0) { 3015 mbedtls_printf("failed\n"); 3016 } 3017 3018 return 1; 3019 } 3020 3021 if (mbedtls_rsa_pkcs1_sign(&rsa, myrand, NULL, 3022 MBEDTLS_MD_SHA1, 20, 3023 sha1sum, rsa_ciphertext) != 0) { 3024 if (verbose != 0) { 3025 mbedtls_printf("failed\n"); 3026 } 3027 3028 ret = 1; 3029 goto cleanup; 3030 } 3031 3032 if (verbose != 0) { 3033 mbedtls_printf("passed\n PKCS#1 sig. verify: "); 3034 } 3035 3036 if (mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA1, 20, 3037 sha1sum, rsa_ciphertext) != 0) { 3038 if (verbose != 0) { 3039 mbedtls_printf("failed\n"); 3040 } 3041 3042 ret = 1; 3043 goto cleanup; 3044 } 3045 3046 if (verbose != 0) { 3047 mbedtls_printf("passed\n"); 3048 } 3049 #endif /* MBEDTLS_MD_CAN_SHA1 */ 3050 3051 if (verbose != 0) { 3052 mbedtls_printf("\n"); 3053 } 3054 3055 cleanup: 3056 mbedtls_mpi_free(&K); 3057 mbedtls_rsa_free(&rsa); 3058 #else /* MBEDTLS_PKCS1_V15 */ 3059 ((void) verbose); 3060 #endif /* MBEDTLS_PKCS1_V15 */ 3061 return ret; 3062 } 3063 3064 #endif /* MBEDTLS_SELF_TEST */ 3065 3066 #endif /* MBEDTLS_RSA_C */