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, *order = NULL;
 245     EC_POINT *pub_key = NULL;
 246
 247     if ((order = BN_new()) == NULL)
 248         goto err;
 249     if ((ctx = BN_CTX_new()) == NULL)
 250         goto err;
 251
 252     if (eckey->priv_key == NULL) {
 253         priv_key = BN_new();
 254         if (priv_key == NULL)
 255             goto err;
 256     } else
 257         priv_key = eckey->priv_key;
 258
 259     if (!EC_GROUP_get_order(eckey->group, order, ctx))
 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     BN_free(order);
 284     if (eckey->pub_key == NULL)
 285         EC_POINT_free(pub_key);
 286     if (eckey->priv_key != priv_key)
 287         BN_free(priv_key);
 288     BN_CTX_free(ctx);
 289     return (ok);
 290 }
 291
 292 int EC_KEY_check_key(const EC_KEY *eckey)
 293 {
 294     int ok = 0;
 295     BN_CTX *ctx = NULL;
 296     const BIGNUM *order = NULL;
 297     EC_POINT *point = NULL;
 298
 299     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 300         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 301         return 0;
 302     }
 303
 304     if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
 305         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_AT_INFINITY);
 306         goto err;
 307     }
 308
 309     if ((ctx = BN_CTX_new()) == NULL)
 310         goto err;
 311     if ((point = EC_POINT_new(eckey->group)) == NULL)
 312         goto err;
 313
 314     /* testing whether the pub_key is on the elliptic curve */
 315     if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
 316         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
 317         goto err;
 318     }
 319     /* testing whether pub_key * order is the point at infinity */
 320     order = eckey->group->order;
 321     if (BN_is_zero(order)) {
 322         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
 323         goto err;
 324     }
 325     if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
 326         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
 327         goto err;
 328     }
 329     if (!EC_POINT_is_at_infinity(eckey->group, point)) {
 330         ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
 331         goto err;
 332     }
 333     /*
 334      * in case the priv_key is present : check if generator * priv_key ==
 335      * pub_key
 336      */
 337     if (eckey->priv_key != NULL) {
 338         if (BN_cmp(eckey->priv_key, order) >= 0) {
 339             ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_WRONG_ORDER);
 340             goto err;
 341         }
 342         if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
 343                           NULL, NULL, ctx)) {
 344             ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_EC_LIB);
 345             goto err;
 346         }
 347         if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
 348             ECerr(EC_F_EC_KEY_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
 349             goto err;
 350         }
 351     }
 352     ok = 1;
 353  err:
 354     BN_CTX_free(ctx);
 355     EC_POINT_free(point);
 356     return (ok);
 357 }
 358
 359 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
 360                                              BIGNUM *y)
 361 {
 362     BN_CTX *ctx = NULL;
 363     BIGNUM *tx, *ty;
 364     EC_POINT *point = NULL;
 365     int ok = 0;
 366 #ifndef OPENSSL_NO_EC2M
 367     int tmp_nid, is_char_two = 0;
 368 #endif
 369
 370     if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
 371         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 372               ERR_R_PASSED_NULL_PARAMETER);
 373         return 0;
 374     }
 375     ctx = BN_CTX_new();
 376     if (ctx == NULL)
 377         goto err;
 378
 379     point = EC_POINT_new(key->group);
 380
 381     if (point == NULL)
 382         goto err;
 383
 384     tx = BN_CTX_get(ctx);
 385     ty = BN_CTX_get(ctx);
 386     if (ty == NULL)
 387         goto err;
 388
 389 #ifndef OPENSSL_NO_EC2M
 390     tmp_nid = EC_METHOD_get_field_type(EC_GROUP_method_of(key->group));
 391
 392     if (tmp_nid == NID_X9_62_characteristic_two_field)
 393         is_char_two = 1;
 394
 395     if (is_char_two) {
 396         if (!EC_POINT_set_affine_coordinates_GF2m(key->group, point,
 397                                                   x, y, ctx))
 398             goto err;
 399         if (!EC_POINT_get_affine_coordinates_GF2m(key->group, point,
 400                                                   tx, ty, ctx))
 401             goto err;
 402     } else
 403 #endif
 404     {
 405         if (!EC_POINT_set_affine_coordinates_GFp(key->group, point,
 406                                                  x, y, ctx))
 407             goto err;
 408         if (!EC_POINT_get_affine_coordinates_GFp(key->group, point,
 409                                                  tx, ty, ctx))
 410             goto err;
 411     }
 412     /*
 413      * Check if retrieved coordinates match originals and are less than field
 414      * order: if not values are out of range.
 415      */
 416     if (BN_cmp(x, tx) || BN_cmp(y, ty)
 417         || (BN_cmp(x, key->group->field) >= 0)
 418         || (BN_cmp(y, key->group->field) >= 0)) {
 419         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 420               EC_R_COORDINATES_OUT_OF_RANGE);
 421         goto err;
 422     }
 423
 424     if (!EC_KEY_set_public_key(key, point))
 425         goto err;
 426
 427     if (EC_KEY_check_key(key) == 0)
 428         goto err;
 429
 430     ok = 1;
 431
 432  err:
 433     BN_CTX_free(ctx);
 434     EC_POINT_free(point);
 435     return ok;
 436
 437 }
 438
 439 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
 440 {
 441     return key->group;
 442 }
 443
 444 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
 445 {
 446     if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
 447         return 0;
 448     EC_GROUP_free(key->group);
 449     key->group = EC_GROUP_dup(group);
 450     return (key->group == NULL) ? 0 : 1;
 451 }
 452
 453 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
 454 {
 455     return key->priv_key;
 456 }
 457
 458 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
 459 {
 460     if (key->meth->set_private != NULL
 461         && key->meth->set_private(key, priv_key) == 0)
 462         return 0;
 463     BN_clear_free(key->priv_key);
 464     key->priv_key = BN_dup(priv_key);
 465     return (key->priv_key == NULL) ? 0 : 1;
 466 }
 467
 468 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
 469 {
 470     return key->pub_key;
 471 }
 472
 473 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
 474 {
 475     if (key->meth->set_public != NULL
 476         && key->meth->set_public(key, pub_key) == 0)
 477         return 0;
 478     EC_POINT_free(key->pub_key);
 479     key->pub_key = EC_POINT_dup(pub_key, key->group);
 480     return (key->pub_key == NULL) ? 0 : 1;
 481 }
 482
 483 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
 484 {
 485     return key->enc_flag;
 486 }
 487
 488 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
 489 {
 490     key->enc_flag = flags;
 491 }
 492
 493 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
 494 {
 495     return key->conv_form;
 496 }
 497
 498 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
 499 {
 500     key->conv_form = cform;
 501     if (key->group != NULL)
 502         EC_GROUP_set_point_conversion_form(key->group, cform);
 503 }
 504
 505 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
 506 {
 507     if (key->group != NULL)
 508         EC_GROUP_set_asn1_flag(key->group, flag);
 509 }
 510
 511 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
 512 {
 513     if (key->group == NULL)
 514         return 0;
 515     return EC_GROUP_precompute_mult(key->group, ctx);
 516 }
 517
 518 int EC_KEY_get_flags(const EC_KEY *key)
 519 {
 520     return key->flags;
 521 }
 522
 523 void EC_KEY_set_flags(EC_KEY *key, int flags)
 524 {
 525     key->flags |= flags;
 526 }
 527
 528 void EC_KEY_clear_flags(EC_KEY *key, int flags)
 529 {
 530     key->flags &= ~flags;
 531 }
 532
 533 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
 534                         unsigned char **pbuf, BN_CTX *ctx)
 535 {
 536     if (key == NULL || key->pub_key == NULL || key->group == NULL)
 537         return 0;
 538     return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
 539 }
 540
 541 int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
 542                    BN_CTX *ctx)
 543 {
 544     if (key == NULL || key->group == NULL)
 545         return 0;
 546     if (key->pub_key == NULL)
 547         key->pub_key = EC_POINT_new(key->group);
 548     if (key->pub_key == NULL)
 549         return 0;
 550     return EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx);
 551 }