crypto/ec/ec_key.c

   1 /*
   2  * Written by Nils Larsch for the OpenSSL project.
   3  */
   4 /* ====================================================================
   5  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  *
  19  * 3. All advertising materials mentioning features or use of this
  20  *    software must display the following acknowledgment:
  21  *    "This product includes software developed by the OpenSSL Project
  22  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  23  *
  24  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  25  *    endorse or promote products derived from this software without
  26  *    prior written permission. For written permission, please contact
  27  *    openssl-core@openssl.org.
  28  *
  29  * 5. Products derived from this software may not be called "OpenSSL"
  30  *    nor may "OpenSSL" appear in their names without prior written
  31  *    permission of the OpenSSL Project.
  32  *
  33  * 6. Redistributions of any form whatsoever must retain the following
  34  *    acknowledgment:
  35  *    "This product includes software developed by the OpenSSL Project
  36  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  37  *
  38  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  39  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  40  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  41  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  44  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  45  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  46  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  47  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  48  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  49  * OF THE POSSIBILITY OF SUCH DAMAGE.
  50  * ====================================================================
  51  *
  52  * This product includes cryptographic software written by Eric Young
  53  * (eay@cryptsoft.com).  This product includes software written by Tim
  54  * Hudson (tjh@cryptsoft.com).
  55  *
  56  */
  57 /* ====================================================================
  58  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  59  * Portions originally developed by SUN MICROSYSTEMS, INC., and
  60  * contributed to the OpenSSL project.
  61  */
  62
  63 #include <internal/cryptlib.h>
  64 #include <string.h>
  65 #include "ec_lcl.h"
  66 #include <openssl/err.h>
  67 #ifndef OPENSSL_NO_ENGINE
  68 # include <openssl/engine.h>
  69 #endif
  70
  71 EC_KEY *EC_KEY_new(void)
  72 {
  73     return EC_KEY_new_method(NULL);
  74 }
  75
  76 EC_KEY *EC_KEY_new_by_curve_name(int nid)
  77 {
  78     EC_KEY *ret = EC_KEY_new();
  79     if (ret == NULL)
  80         return NULL;
  81     ret->group = EC_GROUP_new_by_curve_name(nid);
  82     if (ret->group == NULL) {
  83         EC_KEY_free(ret);
  84         return NULL;
  85     }
  86     if (ret->meth->set_group != NULL
  87         && ret->meth->set_group(ret, ret->group) == 0) {
  88         EC_KEY_free(ret);
  89         return NULL;
  90     }
  91     return ret;
  92 }
  93
  94 void EC_KEY_free(EC_KEY *r)
  95 {
  96     int i;
  97
  98     if (r == NULL)
  99         return;
 100
 101     i = CRYPTO_add(&r->references, -1, CRYPTO_LOCK_EC);
 102 #ifdef REF_PRINT
 103     REF_PRINT("EC_KEY", r);
 104 #endif
 105     if (i > 0)
 106         return;
 107 #ifdef REF_CHECK
 108     if (i < 0) {
 109         fprintf(stderr, "EC_KEY_free, bad reference count\n");
 110         abort();
 111     }
 112 #endif
 113
 114     if (r->meth->finish != NULL)
 115         r->meth->finish(r);
 116
 117 #ifndef OPENSSL_NO_ENGINE
 118     if (r->engine != NULL)
 119         ENGINE_finish(r->engine);
 120 #endif
 121
 122     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data);
 123     EC_GROUP_free(r->group);
 124     EC_POINT_free(r->pub_key);
 125     BN_clear_free(r->priv_key);
 126
 127     OPENSSL_clear_free((void *)r, sizeof(EC_KEY));
 128 }
 129
 130 EC_KEY *EC_KEY_copy(EC_KEY *dest, EC_KEY *src)
 131 {
 132     if (dest == NULL || src == NULL) {
 133         ECerr(EC_F_EC_KEY_COPY, ERR_R_PASSED_NULL_PARAMETER);
 134         return NULL;
 135     }
 136     if (src->meth != dest->meth) {
 137         if (dest->meth->finish != NULL)
 138             dest->meth->finish(dest);
 139 #ifndef OPENSSL_NO_ENGINE
 140         if (dest->engine != NULL && ENGINE_finish(dest->engine) == 0)
 141             return 0;
 142         dest->engine = NULL;
 143 #endif
 144     }
 145     /* copy the parameters */
 146     if (src->group != NULL) {
 147         const EC_METHOD *meth = EC_GROUP_method_of(src->group);
 148         /* clear the old group */
 149         EC_GROUP_free(dest->group);
 150         dest->group = EC_GROUP_new(meth);
 151         if (dest->group == NULL)
 152             return NULL;
 153         if (!EC_GROUP_copy(dest->group, src->group))
 154             return NULL;
 155     }
 156     /*  copy the public key */
 157     if (src->pub_key != NULL && src->group != NULL) {
 158         EC_POINT_free(dest->pub_key);
 159         dest->pub_key = EC_POINT_new(src->group);
 160         if (dest->pub_key == NULL)
 161             return NULL;
 162         if (!EC_POINT_copy(dest->pub_key, src->pub_key))
 163             return NULL;
 164     }
 165     /* copy the private key */
 166     if (src->priv_key != NULL) {
 167         if (dest->priv_key == NULL) {
 168             dest->priv_key = BN_new();
 169             if (dest->priv_key == NULL)
 170                 return NULL;
 171         }
 172         if (!BN_copy(dest->priv_key, src->priv_key))
 173             return NULL;
 174     }
 175
 176     /* copy the rest */
 177     dest->enc_flag = src->enc_flag;
 178     dest->conv_form = src->conv_form;
 179     dest->version = src->version;
 180     dest->flags = src->flags;
 181     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY,
 182                             &dest->ex_data, &src->ex_data))
 183         return NULL;
 184
 185     if (src->meth != dest->meth) {
 186 #ifndef OPENSSL_NO_ENGINE
 187         if (src->engine != NULL && ENGINE_init(src->engine) == 0)
 188             return NULL;
 189         dest->engine = src->engine;
 190 #endif
 191         dest->meth = src->meth;
 192     }
 193
 194     if (src->meth->copy != NULL && src->meth->copy(dest, src) == 0)
 195         return NULL;
 196
 197     return dest;
 198 }
 199
 200 EC_KEY *EC_KEY_dup(EC_KEY *ec_key)
 201 {
 202     EC_KEY *ret = EC_KEY_new_method(ec_key->engine);
 203
 204     if (ret == NULL)
 205         return NULL;
 206     if (EC_KEY_copy(ret, ec_key) == NULL) {
 207         EC_KEY_free(ret);
 208         return NULL;
 209     }
 210     return ret;
 211 }
 212
 213 int EC_KEY_up_ref(EC_KEY *r)
 214 {
 215     int i = CRYPTO_add(&r->references, 1, CRYPTO_LOCK_EC);
 216 #ifdef REF_PRINT
 217     REF_PRINT("EC_KEY", r);
 218 #endif
 219 #ifdef REF_CHECK
 220     if (i < 2) {
 221         fprintf(stderr, "EC_KEY_up, bad reference count\n");
 222         abort();
 223     }
 224 #endif
 225     return ((i > 1) ? 1 : 0);
 226 }
 227
 228 int EC_KEY_generate_key(EC_KEY *eckey)
 229 {
 230     if (eckey == NULL || eckey->group == NULL) {
 231         ECerr(EC_F_EC_KEY_GENERATE_KEY, ERR_R_PASSED_NULL_PARAMETER);
 232         return 0;
 233     }
 234     if (eckey->meth->keygen != NULL)
 235         return eckey->meth->keygen(eckey);
 236     ECerr(EC_F_EC_KEY_GENERATE_KEY, EC_R_OPERATION_NOT_SUPPORTED);
 237     return 0;
 238 }
 239
 240 int ossl_ec_key_gen(EC_KEY *eckey)
 241 {
 242     int ok = 0;
 243     BN_CTX *ctx = NULL;
 244     BIGNUM *priv_key = NULL;
 245     const BIGNUM *order = NULL;
 246     EC_POINT *pub_key = NULL;
 247
 248     if ((ctx = BN_CTX_new()) == NULL)
 249         goto err;
 250
 251     if (eckey->priv_key == NULL) {
 252         priv_key = BN_new();
 253         if (priv_key == NULL)
 254             goto err;
 255     } else
 256         priv_key = eckey->priv_key;
 257
 258     order = EC_GROUP_get0_order(eckey->group);
 259     if (order == NULL)
 260         goto err;
 261
 262     do
 263         if (!BN_rand_range(priv_key, order))
 264             goto err;
 265     while (BN_is_zero(priv_key)) ;
 266
 267     if (eckey->pub_key == NULL) {
 268         pub_key = EC_POINT_new(eckey->group);
 269         if (pub_key == NULL)
 270             goto err;
 271     } else
 272         pub_key = eckey->pub_key;
 273
 274     if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx))
 275         goto err;
 276
 277     eckey->priv_key = priv_key;
 278     eckey->pub_key = pub_key;
 279
 280     ok = 1;
 281
 282  err:
 283     if (eckey->pub_key == NULL)
 284         EC_POINT_free(pub_key);
 285     if (eckey->priv_key != priv_key)
 286         BN_free(priv_key);
 287     BN_CTX_free(ctx);
 288     return (ok);
 289 }
 290
 291 int EC_KEY_check_key(const EC_KEY *eckey)
 292 {
 293     int ok = 0;
 294     BN_CTX *ctx = NULL;
 295     const BIGNUM *order = NULL;
 296     EC_POINT *point = NULL;
 297
 298     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 299         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 300         return 0;
 301     }
 302
 303     if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
 304         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_AT_INFINITY);
 305         goto err;
 306     }
 307
 308     if ((ctx = BN_CTX_new()) == NULL)
 309         goto err;
 310     if ((point = EC_POINT_new(eckey->group)) == NULL)
 311         goto err;
 312
 313     /* testing whether the pub_key is on the elliptic curve */
 314     if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
 315         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
 316         goto err;
 317     }
 318     /* testing whether pub_key * order is the point at infinity */
 319     order = eckey->group->order;
 320     if (BN_is_zero(order)) {
 321         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
 322         goto err;
 323     }
 324     if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
 325         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
 326         goto err;
 327     }
 328     if (!EC_POINT_is_at_infinity(eckey->group, point)) {
 329         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
 330         goto err;
 331     }
 332     /*
 333      * in case the priv_key is present : check if generator * priv_key ==
 334      * pub_key
 335      */
 336     if (eckey->priv_key != NULL) {
 337         if (BN_cmp(eckey->priv_key, order) >= 0) {
 338             ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
 339             goto err;
 340         }
 341         if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
 342                           NULL, NULL, ctx)) {
 343             ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
 344             goto err;
 345         }
 346         if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
 347             ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
 348             goto err;
 349         }
 350     }
 351     ok = 1;
 352  err:
 353     BN_CTX_free(ctx);
 354     EC_POINT_free(point);
 355     return (ok);
 356 }
 357
 358 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
 359                                              BIGNUM *y)
 360 {
 361     BN_CTX *ctx = NULL;
 362     BIGNUM *tx, *ty;
 363     EC_POINT *point = NULL;
 364     int ok = 0;
 365 #ifndef OPENSSL_NO_EC2M
 366     int tmp_nid, is_char_two = 0;
 367 #endif
 368
 369     if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
 370         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 371               ERR_R_PASSED_NULL_PARAMETER);
 372         return 0;
 373     }
 374     ctx = BN_CTX_new();
 375     if (ctx == NULL)
 376         goto err;
 377
 378     point = EC_POINT_new(key->group);
 379
 380     if (point == NULL)
 381         goto err;
 382
 383     tx = BN_CTX_get(ctx);
 384     ty = BN_CTX_get(ctx);
 385     if (ty == NULL)
 386         goto err;
 387
 388 #ifndef OPENSSL_NO_EC2M
 389     tmp_nid = EC_METHOD_get_field_type(EC_GROUP_method_of(key->group));
 390
 391     if (tmp_nid == NID_X9_62_characteristic_two_field)
 392         is_char_two = 1;
 393
 394     if (is_char_two) {
 395         if (!EC_POINT_set_affine_coordinates_GF2m(key->group, point,
 396                                                   x, y, ctx))
 397             goto err;
 398         if (!EC_POINT_get_affine_coordinates_GF2m(key->group, point,
 399                                                   tx, ty, ctx))
 400             goto err;
 401     } else
 402 #endif
 403     {
 404         if (!EC_POINT_set_affine_coordinates_GFp(key->group, point,
 405                                                  x, y, ctx))
 406             goto err;
 407         if (!EC_POINT_get_affine_coordinates_GFp(key->group, point,
 408                                                  tx, ty, ctx))
 409             goto err;
 410     }
 411     /*
 412      * Check if retrieved coordinates match originals and are less than field
 413      * order: if not values are out of range.
 414      */
 415     if (BN_cmp(x, tx) || BN_cmp(y, ty)
 416         || (BN_cmp(x, key->group->field) >= 0)
 417         || (BN_cmp(y, key->group->field) >= 0)) {
 418         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 419               EC_R_COORDINATES_OUT_OF_RANGE);
 420         goto err;
 421     }
 422
 423     if (!EC_KEY_set_public_key(key, point))
 424         goto err;
 425
 426     if (EC_KEY_check_key(key) == 0)
 427         goto err;
 428
 429     ok = 1;
 430
 431  err:
 432     BN_CTX_free(ctx);
 433     EC_POINT_free(point);
 434     return ok;
 435
 436 }
 437
 438 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
 439 {
 440     return key->group;
 441 }
 442
 443 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
 444 {
 445     if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
 446         return 0;
 447     EC_GROUP_free(key->group);
 448     key->group = EC_GROUP_dup(group);
 449     return (key->group == NULL) ? 0 : 1;
 450 }
 451
 452 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
 453 {
 454     return key->priv_key;
 455 }
 456
 457 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
 458 {
 459     if (key->meth->set_private != NULL
 460         && key->meth->set_private(key, priv_key) == 0)
 461         return 0;
 462     BN_clear_free(key->priv_key);
 463     key->priv_key = BN_dup(priv_key);
 464     return (key->priv_key == NULL) ? 0 : 1;
 465 }
 466
 467 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
 468 {
 469     return key->pub_key;
 470 }
 471
 472 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
 473 {
 474     if (key->meth->set_public != NULL
 475         && key->meth->set_public(key, pub_key) == 0)
 476         return 0;
 477     EC_POINT_free(key->pub_key);
 478     key->pub_key = EC_POINT_dup(pub_key, key->group);
 479     return (key->pub_key == NULL) ? 0 : 1;
 480 }
 481
 482 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
 483 {
 484     return key->enc_flag;
 485 }
 486
 487 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
 488 {
 489     key->enc_flag = flags;
 490 }
 491
 492 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
 493 {
 494     return key->conv_form;
 495 }
 496
 497 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
 498 {
 499     key->conv_form = cform;
 500     if (key->group != NULL)
 501         EC_GROUP_set_point_conversion_form(key->group, cform);
 502 }
 503
 504 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
 505 {
 506     if (key->group != NULL)
 507         EC_GROUP_set_asn1_flag(key->group, flag);
 508 }
 509
 510 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
 511 {
 512     if (key->group == NULL)
 513         return 0;
 514     return EC_GROUP_precompute_mult(key->group, ctx);
 515 }
 516
 517 int EC_KEY_get_flags(const EC_KEY *key)
 518 {
 519     return key->flags;
 520 }
 521
 522 void EC_KEY_set_flags(EC_KEY *key, int flags)
 523 {
 524     key->flags |= flags;
 525 }
 526
 527 void EC_KEY_clear_flags(EC_KEY *key, int flags)
 528 {
 529     key->flags &= ~flags;
 530 }
 531
 532 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
 533                         unsigned char **pbuf, BN_CTX *ctx)
 534 {
 535     if (key == NULL || key->pub_key == NULL || key->group == NULL)
 536         return 0;
 537     return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
 538 }
 539
 540 int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
 541                    BN_CTX *ctx)
 542 {
 543     if (key == NULL || key->group == NULL)
 544         return 0;
 545     if (key->pub_key == NULL)
 546         key->pub_key = EC_POINT_new(key->group);
 547     if (key->pub_key == NULL)
 548         return 0;
 549     return EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx);
 550 }
 551
 552 size_t EC_KEY_priv2oct(const EC_KEY *eckey, unsigned char *buf, size_t len)
 553 {
 554     size_t buf_len, bn_len;
 555     if (eckey->group == NULL || eckey->group->meth == NULL)
 556         return 0;
 557
 558     buf_len = (EC_GROUP_get_degree(eckey->group) + 7) / 8;
 559     if (eckey->priv_key == NULL)
 560         return 0;
 561     if (buf == NULL)
 562         return buf_len;
 563     else if (len < buf_len)
 564         return 0;
 565
 566     bn_len = (size_t)BN_num_bytes(eckey->priv_key);
 567
 568     /* Octetstring may need leading zeros if BN is to short */
 569
 570     if (bn_len > buf_len) {
 571         ECerr(EC_F_EC_KEY_PRIV2OCT, EC_R_BUFFER_TOO_SMALL);
 572         return 0;
 573     }
 574
 575     if (!BN_bn2bin(eckey->priv_key, buf + buf_len - bn_len)) {
 576         ECerr(EC_F_EC_KEY_PRIV2OCT, ERR_R_BN_LIB);
 577         return 0;
 578     }
 579
 580     if (buf_len - bn_len > 0)
 581         memset(buf, 0, buf_len - bn_len);
 582
 583     return buf_len;
 584 }
 585
 586 int EC_KEY_oct2priv(EC_KEY *eckey, unsigned char *buf, size_t len)
 587 {
 588     if (eckey->group == NULL || eckey->group->meth == NULL)
 589         return 0;
 590
 591     if (eckey->priv_key == NULL)
 592         eckey->priv_key = BN_secure_new();
 593     if (eckey->priv_key == NULL) {
 594         ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_MALLOC_FAILURE);
 595         return 0;
 596     }
 597     eckey->priv_key = BN_bin2bn(buf, len, eckey->priv_key);
 598     if (eckey->priv_key == NULL) {
 599         ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_BN_LIB);
 600         return 0;
 601     }
 602     return 1;
 603 }