crypto/ec/ec_key.c

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