1 /*- 2 * Copyright (c) 2012 Alistair Crooks <agc@NetBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 #include "config.h" 26 27 #include <sys/types.h> 28 #include <sys/syslog.h> 29 30 #ifdef _KERNEL 31 # include <sys/kmem.h> 32 # define logmessage log 33 #else 34 # include <stdio.h> 35 # include <stdlib.h> 36 # include <string.h> 37 # include <unistd.h> 38 #endif 39 40 #include "misc.h" 41 #include "digest.h" 42 #include "rsa.h" 43 44 #ifndef USE_ARG 45 #define USE_ARG(x) /*LINTED*/(void)&(x) 46 #endif 47 48 #define RSA_MAX_MODULUS_BITS 16384 49 #define RSA_SMALL_MODULUS_BITS 3072 50 #define RSA_MAX_PUBEXP_BITS 64 /* exponent limit enforced for "large" modulus only */ 51 52 static int 53 rsa_padding_check_none(uint8_t *to, int tlen, const uint8_t *from, int flen, int num) 54 { 55 USE_ARG(num); 56 if (flen > tlen) { 57 printf("r too large\n"); 58 return -1; 59 } 60 (void) memset(to, 0x0, tlen - flen); 61 (void) memcpy(to + tlen - flen, from, flen); 62 return tlen; 63 } 64 65 static int 66 lowlevel_rsa_private_encrypt(int plainc, const unsigned char *plain, unsigned char *encbuf, RSA *rsa) 67 { 68 BIGNUM *decbn; 69 BIGNUM *signedbn; 70 uint8_t *decbuf; 71 int nbytes; 72 int signc; 73 int signedbytes; 74 int r; 75 76 decbuf = NULL; 77 r = -1; 78 decbn = BN_new(); 79 signedbn = BN_new(); 80 nbytes = BN_num_bytes(rsa->n); 81 decbuf = netpgp_allocate(1, nbytes); 82 /* add no padding */ 83 memcpy(decbuf, plain, plainc); 84 BN_bin2bn(decbuf, nbytes, decbn); 85 if (BN_cmp(decbn, rsa->n) >= 0) { 86 printf("decbn too big\n"); 87 goto err; 88 } 89 if (!BN_mod_exp(signedbn, decbn, rsa->d, rsa->n, NULL)) { 90 printf("bad mod_exp\n"); 91 goto err; 92 } 93 signedbytes = BN_num_bytes(signedbn); 94 signc = BN_bn2bin(signedbn, &encbuf[nbytes - signedbytes]); 95 memset(encbuf, 0x0, nbytes - signc); 96 r = nbytes; 97 err: 98 netpgp_deallocate(decbuf, nbytes); 99 BN_clear_free(decbn); 100 BN_clear_free(signedbn); 101 return r; 102 } 103 104 static int 105 lowlevel_rsa_public_encrypt(int plainc, const unsigned char *plain, unsigned char *encbuf, RSA *rsa) 106 { 107 BIGNUM *decbn; 108 BIGNUM *encbn; 109 uint8_t *decbuf; 110 int nbytes; 111 int encc; 112 int r; 113 int i; 114 115 r = -1; 116 decbn = BN_new(); 117 encbn = BN_new(); 118 nbytes = BN_num_bytes(rsa->n); 119 decbuf = netpgp_allocate(1, nbytes); 120 (void) memcpy(decbuf, plain, plainc); 121 if (BN_bin2bn(decbuf, nbytes, decbn) == NULL) { 122 printf("bin2bn failed\n"); 123 goto err; 124 } 125 if (BN_cmp(decbn, rsa->n) >= 0) { 126 printf("BN_cmp failed\n"); 127 goto err; 128 } 129 if (!BN_mod_exp(encbn, decbn, rsa->e, rsa->n, NULL)) { 130 printf("BN_mod_exp failed\n"); 131 goto err; 132 } 133 encc = BN_num_bytes(encbn); 134 i = BN_bn2bin(encbn, &encbuf[nbytes - encc]); 135 (void) memset(encbuf, 0x0, nbytes - i); 136 r = nbytes; 137 err: 138 if (decbuf) { 139 memset(decbuf, 0x0, nbytes); 140 netpgp_deallocate(decbuf, nbytes); 141 } 142 BN_clear_free(decbn); 143 BN_clear_free(encbn); 144 return r; 145 } 146 147 static int 148 lowlevel_rsa_private_decrypt(int enclen, const unsigned char *encbuf, unsigned char *to, RSA *rsa) 149 { 150 BIGNUM *encbn; 151 BIGNUM *decbn; 152 uint8_t *buf; 153 int nbytes; 154 int j; 155 int r; 156 157 r = -1; 158 decbn = encbn = NULL; 159 buf = NULL; 160 if (BN_num_bits(rsa->n) > RSA_MAX_MODULUS_BITS) { 161 return -1; 162 } 163 if (BN_cmp(rsa->n, rsa->e) <= 0) { 164 return -1; 165 } 166 encbn = BN_new(); 167 decbn = BN_new(); 168 nbytes = BN_num_bytes(rsa->n); 169 buf = netpgp_allocate(1, nbytes); 170 if (enclen > nbytes) { 171 printf("bad enclen\n"); 172 goto err; 173 } 174 BN_bin2bn(encbuf, enclen, encbn); 175 if (BN_cmp(encbn, rsa->n) >= 0) { 176 printf("bad encbn\n"); 177 goto err; 178 } 179 BN_mod_exp(decbn, encbn, rsa->d, rsa->n, NULL); 180 j = BN_bn2bin(decbn, buf); 181 r = rsa_padding_check_none(to, nbytes, buf, j, nbytes); 182 err: 183 BN_clear_free(encbn); 184 BN_clear_free(decbn); 185 netpgp_deallocate(buf, nbytes); 186 return r; 187 } 188 189 static int 190 lowlevel_rsa_public_decrypt(const uint8_t *encbuf, int enclen, uint8_t *dec, const rsa_pubkey_t *rsa) 191 { 192 uint8_t *decbuf; 193 BIGNUM *decbn; 194 BIGNUM *encbn; 195 int decbytes; 196 int nbytes; 197 int r; 198 199 nbytes = 0; 200 r = -1; 201 decbuf = NULL; 202 decbn = encbn = NULL; 203 if (BN_num_bits(rsa->n) > RSA_MAX_MODULUS_BITS) { 204 printf("rsa r modulus too large\n"); 205 goto err; 206 } 207 if (BN_cmp(rsa->n, rsa->e) <= 0) { 208 printf("rsa r bad n value\n"); 209 goto err; 210 } 211 if (BN_num_bits(rsa->n) > RSA_SMALL_MODULUS_BITS && 212 BN_num_bits(rsa->e) > RSA_MAX_PUBEXP_BITS) { 213 printf("rsa r bad exponent limit\n"); 214 goto err; 215 } 216 if ((encbn = BN_new()) == NULL || 217 (decbn = BN_new()) == NULL || 218 (decbuf = netpgp_allocate(1, nbytes = BN_num_bytes(rsa->n))) == NULL) { 219 printf("allocation failure\n"); 220 goto err; 221 } 222 if (enclen > nbytes) { 223 printf("rsa r > mod len\n"); 224 goto err; 225 } 226 if (BN_bin2bn(encbuf, enclen, encbn) == NULL) { 227 printf("null encrypted BN\n"); 228 goto err; 229 } 230 if (BN_cmp(encbn, rsa->n) >= 0) { 231 printf("rsa r data too large for modulus\n"); 232 goto err; 233 } 234 if (BN_mod_exp(decbn, encbn, rsa->e, rsa->n, NULL) < 0) { 235 printf("BN_mod_exp < 0\n"); 236 goto err; 237 } 238 decbytes = BN_num_bytes(decbn); 239 (void) BN_bn2bin(decbn, decbuf); 240 if ((r = rsa_padding_check_none(dec, nbytes, decbuf, decbytes, 0)) < 0) { 241 printf("rsa r padding check failed\n"); 242 } 243 err: 244 BN_free(encbn); 245 BN_free(decbn); 246 if (decbuf != NULL) { 247 (void) memset(decbuf, 0x0, nbytes); 248 netpgp_deallocate(decbuf, nbytes); 249 } 250 return r; 251 } 252 253 #if 0 254 /** 255 @file rsa_make_key.c 256 RSA key generation, Tom St Denis 257 */ 258 259 /** 260 Create an RSA key 261 @param prng An active PRNG state 262 @param wprng The index of the PRNG desired 263 @param size The size of the modulus (key size) desired (octets) 264 @param e The "e" value (public key). e==65537 is a good choice 265 @param key [out] Destination of a newly created private key pair 266 @return CRYPT_OK if successful, upon error all allocated ram is freed 267 */ 268 static int 269 rsa_make_key(prng_state *prng, int wprng, int size, long e, rsa_key *key) 270 { 271 void *p, *q, *tmp1, *tmp2, *tmp3; 272 int err; 273 274 LTC_ARGCHK(ltc_mp.name != NULL); 275 LTC_ARGCHK(key != NULL); 276 277 if ((size < (MIN_RSA_SIZE/8)) || (size > (MAX_RSA_SIZE/8))) { 278 return CRYPT_INVALID_KEYSIZE; 279 } 280 281 if ((e < 3) || ((e & 1) == 0)) { 282 return CRYPT_INVALID_ARG; 283 } 284 285 if ((err = prng_is_valid(wprng)) != CRYPT_OK) { 286 return err; 287 } 288 289 if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != CRYPT_OK) { 290 return err; 291 } 292 293 /* make primes p and q (optimization provided by Wayne Scott) */ 294 /* tmp3 = e */ 295 if ((err = mp_set_int(tmp3, e)) != CRYPT_OK) { 296 goto errkey; 297 } 298 299 /* make prime "p" */ 300 do { 301 if ((err = rand_prime( p, size/2, prng, wprng)) != CRYPT_OK) { 302 goto errkey; 303 } 304 /* tmp1 = p-1 */ 305 if ((err = mp_sub_d( p, 1, tmp1)) != CRYPT_OK) { 306 goto errkey; 307 } 308 /* tmp2 = gcd(p-1, e) */ 309 if ((err = mp_gcd( tmp1, tmp3, tmp2)) != CRYPT_OK) { 310 goto errkey; 311 } 312 } while (mp_cmp_d( tmp2, 1) != 0); 313 /* while e divides p-1 */ 314 315 /* make prime "q" */ 316 do { 317 if ((err = rand_prime( q, size/2, prng, wprng)) != CRYPT_OK) { 318 goto errkey; 319 } 320 /* tmp1 = q-1 */ 321 if ((err = mp_sub_d( q, 1, tmp1)) != CRYPT_OK) { 322 goto errkey; 323 } 324 /* tmp2 = gcd(q-1, e) */ 325 if ((err = mp_gcd( tmp1, tmp3, tmp2)) != CRYPT_OK) { 326 goto errkey; 327 } 328 } while (mp_cmp_d( tmp2, 1) != 0); 329 /* while e divides q-1 */ 330 331 /* tmp1 = lcm(p-1, q-1) */ 332 /* tmp2 = p-1 */ 333 if ((err = mp_sub_d( p, 1, tmp2)) != CRYPT_OK) { 334 goto errkey; 335 } 336 /* tmp1 = q-1 (previous do/while loop) */ 337 /* tmp1 = lcm(p-1, q-1) */ 338 if ((err = mp_lcm( tmp1, tmp2, tmp1)) != CRYPT_OK) { 339 goto errkey; 340 } 341 342 /* make key */ 343 if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP, &key->p, &key->q, NULL)) != CRYPT_OK) { 344 goto errkey; 345 } 346 347 /* key->e = e */ 348 if ((err = mp_set_int( key->e, e)) != CRYPT_OK) { 349 goto errkey; 350 } 351 /* key->d = 1/e mod lcm(p-1,q-1) */ 352 if ((err = mp_invmod( key->e, tmp1, key->d)) != CRYPT_OK) { 353 goto errkey; 354 } 355 /* key->N = pq */ 356 if ((err = mp_mul( p, q, key->N)) != CRYPT_OK) { 357 goto errkey; 358 } 359 360 /* optimize for CRT now */ 361 /* find d mod q-1 and d mod p-1 */ 362 /* tmp1 = q-1 */ 363 if ((err = mp_sub_d( p, 1, tmp1)) != CRYPT_OK) { 364 goto errkey; 365 } 366 /* tmp2 = p-1 */ 367 if ((err = mp_sub_d( q, 1, tmp2)) != CRYPT_OK) { 368 goto errkey; 369 } 370 /* dP = d mod p-1 */ 371 if ((err = mp_mod( key->d, tmp1, key->dP)) != CRYPT_OK) { 372 goto errkey; 373 } 374 /* dQ = d mod q-1 */ 375 if ((err = mp_mod( key->d, tmp2, key->dQ)) != CRYPT_OK) { 376 goto errkey; 377 } 378 /* qP = 1/q mod p */ 379 if ((err = mp_invmod( q, p, key->qP)) != CRYPT_OK) { 380 got oerrkey; 381 } 382 383 if ((err = mp_copy( p, key->p)) != CRYPT_OK) { 384 goto errkey; 385 } 386 if ((err = mp_copy( q, key->q)) != CRYPT_OK) { 387 goto errkey; 388 } 389 390 /* set key type (in this case it's CRT optimized) */ 391 key->type = PK_PRIVATE; 392 393 /* return ok and free temps */ 394 err = CRYPT_OK; 395 goto cleanup; 396 errkey: 397 mp_clear_multi(key->d, key->e, key->N, key->dQ, key->dP, key->qP, key->p, key->q, NULL); 398 cleanup: 399 mp_clear_multi(tmp3, tmp2, tmp1, p, q, NULL); 400 return err; 401 } 402 #endif 403 404 #define HASHBUF_LEN 512 405 406 #define DSA_MAX_MODULUS_BITS 10000 407 408 static int 409 dsa_do_verify(const unsigned char *calculated, int dgst_len, const dsasig_t *sig, mpi_dsa_t *dsa) 410 { 411 BIGNUM *M; 412 BIGNUM *W; 413 BIGNUM *t1; 414 int ret = -1; 415 int qbits; 416 417 if (dsa->p == NULL || dsa->q == NULL || dsa->g == NULL) { 418 return 0; 419 } 420 M = W = t1 = NULL; 421 qbits = BN_num_bits(dsa->q); 422 switch(qbits) { 423 case 160: 424 case 224: 425 case 256: 426 /* openssl sources say these are the valid values */ 427 /* according to FIPS 186-3 */ 428 break; 429 default: 430 printf("dsa: bad # of Q bits\n"); 431 return 0; 432 } 433 if (BN_num_bits(dsa->p) > DSA_MAX_MODULUS_BITS) { 434 printf("dsa: p too large\n"); 435 return 0; 436 } 437 /* no love for SHA512? */ 438 if (dgst_len > SHA256_DIGEST_LENGTH) { 439 printf("dsa: digest too long\n"); 440 return 0; 441 } 442 ret = 0; 443 if ((M = BN_new()) == NULL || 444 (W = BN_new()) == NULL || 445 (t1 = BN_new()) == NULL) { 446 goto err; 447 } 448 if (BN_is_zero(sig->r) || 449 BN_is_negative(sig->r) || 450 BN_cmp(sig->r, dsa->q) >= 0) { 451 goto err; 452 } 453 if (BN_is_zero(sig->s) || 454 BN_is_negative(sig->s) || 455 BN_cmp(sig->s, dsa->q) >= 0) { 456 goto err; 457 } 458 if (BN_mod_inverse(W, sig->s, dsa->q, NULL) != MP_OKAY) { 459 goto err; 460 } 461 if (dgst_len > qbits / 8) { 462 dgst_len = qbits / 8; 463 } 464 if (BN_bin2bn(calculated, dgst_len, M) == NULL) { 465 goto err; 466 } 467 if (!BN_mod_mul(M, M, W, dsa->q, NULL)) { 468 goto err; 469 } 470 if (!BN_mod_mul(W, sig->r, W, dsa->q, NULL)) { 471 goto err; 472 } 473 if (!BN_mod_exp(dsa->p, t1, dsa->g, M, NULL)) { 474 goto err; 475 } 476 if (!BN_div(NULL, M, t1, dsa->q, NULL)) { 477 goto err; 478 } 479 ret = (BN_cmp(M, sig->r) == 0); 480 err: 481 if (M) { 482 BN_free(M); 483 } 484 if (W) { 485 BN_free(W); 486 } 487 if (t1) { 488 BN_free(t1); 489 } 490 return ret; 491 } 492 493 /*************************************************************************/ 494 495 int 496 RSA_size(const RSA *rsa) 497 { 498 return (rsa == NULL) ? 0 : BN_num_bits(rsa->n); 499 } 500 501 int 502 DSA_size(const DSA *dsa) 503 { 504 return (dsa == NULL) ? 0 : BN_num_bits(dsa->p); 505 } 506 507 unsigned 508 dsa_verify(const signature_t *signature, const dsa_pubkey_t *pubdsa, const uint8_t *calculated, size_t hash_length) 509 { 510 mpi_dsa_t odsa; 511 dsasig_t osig; 512 unsigned qlen; 513 int ret; 514 515 if (signature == NULL || pubdsa == NULL || calculated == NULL) { 516 return -1; 517 } 518 (void) memset(&osig, 0x0, sizeof(osig)); 519 (void) memset(&odsa, 0x0, sizeof(odsa)); 520 BN_copy(osig.r, signature->dsa.r); 521 BN_copy(osig.s, signature->dsa.s); 522 odsa.p = pubdsa->p; 523 odsa.q = pubdsa->q; 524 odsa.g = pubdsa->g; 525 odsa.pub_key = pubdsa->y; 526 if ((qlen = BN_num_bytes(odsa.q)) < hash_length) { 527 hash_length = qlen; 528 } 529 ret = dsa_do_verify(calculated, (int)hash_length, &signature->dsa, &odsa); 530 if (ret < 0) { 531 return 0; 532 } 533 BN_free(odsa.p); 534 BN_free(odsa.q); 535 BN_free(odsa.g); 536 BN_free(odsa.pub_key); 537 odsa.p = odsa.q = odsa.g = odsa.pub_key = NULL; 538 BN_free(osig.r); 539 BN_free(osig.s); 540 osig.r = osig.s = NULL; 541 return (unsigned)ret; 542 } 543 544 RSA * 545 RSA_new(void) 546 { 547 return netpgp_allocate(1, sizeof(RSA)); 548 } 549 550 void 551 RSA_free(RSA *rsa) 552 { 553 if (rsa) { 554 netpgp_deallocate(rsa, sizeof(*rsa)); 555 } 556 } 557 558 int 559 RSA_check_key(RSA *rsa) 560 { 561 BIGNUM *calcn; 562 int ret; 563 564 ret = 0; 565 if (rsa == NULL || rsa->p == NULL || rsa->q == NULL || rsa->n == NULL) { 566 return -1; 567 } 568 /* check that p and q are coprime, and that n = p*q. */ 569 if (!BN_is_prime(rsa->p, 1, NULL, NULL, NULL) || 570 !BN_is_prime(rsa->q, 1, NULL, NULL, NULL)) { 571 return 0; 572 } 573 calcn = BN_new(); 574 BN_mul(calcn, rsa->p, rsa->q, NULL); 575 if (BN_cmp(calcn, rsa->n) != 0) { 576 goto errout; 577 } 578 /* XXX - check that d*e = 1 mod (p-1*q-1) */ 579 ret = 1; 580 errout: 581 BN_clear_free(calcn); 582 return ret; 583 } 584 585 RSA * 586 RSA_generate_key(int num, unsigned long e, void (*callback)(int,int,void *), void *cb_arg) 587 { 588 /* STUBBED */ 589 USE_ARG(num); 590 USE_ARG(e); 591 USE_ARG(callback); 592 USE_ARG(cb_arg); 593 printf("RSA_generate_key stubbed\n"); 594 return RSA_new(); 595 } 596 597 /* encrypt */ 598 int 599 RSA_public_encrypt(int plainc, const unsigned char *plain, unsigned char *encbuf, RSA *rsa, int padding) 600 { 601 USE_ARG(padding); 602 if (plain == NULL || encbuf == NULL || rsa == NULL) { 603 return -1; 604 } 605 return lowlevel_rsa_public_encrypt(plainc, plain, encbuf, rsa); 606 } 607 608 /* decrypt */ 609 int 610 RSA_private_decrypt(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) 611 { 612 USE_ARG(padding); 613 if (from == NULL || to == NULL || rsa == NULL) { 614 return -1; 615 } 616 return lowlevel_rsa_private_decrypt(flen, from, to, rsa); 617 } 618 619 /* sign */ 620 int 621 RSA_private_encrypt(int plainc, const unsigned char *plain, unsigned char *encbuf, RSA *rsa, int padding) 622 { 623 USE_ARG(padding); 624 if (plain == NULL || encbuf == NULL || rsa == NULL) { 625 return -1; 626 } 627 return lowlevel_rsa_private_encrypt(plainc, plain, encbuf, rsa); 628 } 629 630 /* verify */ 631 int 632 RSA_public_decrypt(int enclen, const unsigned char *enc, unsigned char *dec, RSA *rsa, int padding) 633 { 634 rsa_pubkey_t pub; 635 int ret; 636 637 if (enc == NULL || dec == NULL || rsa == NULL) { 638 return 0; 639 } 640 USE_ARG(padding); 641 (void) memset(&pub, 0x0, sizeof(pub)); 642 pub.n = BN_dup(rsa->n); 643 pub.e = BN_dup(rsa->e); 644 ret = lowlevel_rsa_public_decrypt(enc, enclen, dec, &pub); 645 BN_free(pub.n); 646 BN_free(pub.e); 647 return ret; 648 } 649 650 /***********************************************************************/ 651 652 DSA * 653 DSA_new(void) 654 { 655 return netpgp_allocate(1, sizeof(DSA)); 656 } 657 658 void 659 DSA_free(DSA *dsa) 660 { 661 if (dsa) { 662 netpgp_deallocate(dsa, sizeof(*dsa)); 663 } 664 } 665 666 DSA_SIG * 667 DSA_SIG_new(void) 668 { 669 return netpgp_allocate(1, sizeof(DSA_SIG)); 670 } 671 672 void 673 DSA_SIG_free(DSA_SIG *sig) 674 { 675 if (sig) { 676 netpgp_deallocate(sig, sizeof(*sig)); 677 } 678 } 679 680 DSA_SIG * 681 DSA_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) 682 { 683 /* STUBBED */ 684 USE_ARG(dgst); 685 USE_ARG(dlen); 686 USE_ARG(dsa); 687 printf("DSA_do_sign stubbed\n"); 688 return DSA_SIG_new(); 689 } 690 691 int 692 DSA_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, DSA *dsa) 693 { 694 if (dgst == NULL || dgst_len == 0 || sig == NULL || dsa == NULL) { 695 return -1; 696 } 697 return dsa_do_verify(dgst, dgst_len, sig, dsa); 698 } 699