crypto/ec/ec_key.c

   1 /*
   2  * Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 /*
  12  * ECDSA low level APIs are deprecated for public use, but still ok for
  13  * internal use.
  14  */
  15 #include "internal/deprecated.h"
  16
  17 #include "internal/cryptlib.h"
  18 #include <string.h>
  19 #include "ec_local.h"
  20 #include "internal/refcount.h"
  21 #include <openssl/err.h>
  22 #include <openssl/engine.h>
  23
  24 #ifndef FIPS_MODE
  25 EC_KEY *EC_KEY_new(void)
  26 {
  27     return ec_key_new_method_int(NULL, NULL);
  28 }
  29 #endif
  30
  31 EC_KEY *EC_KEY_new_ex(OPENSSL_CTX *ctx)
  32 {
  33     return ec_key_new_method_int(ctx, NULL);
  34 }
  35
  36 EC_KEY *EC_KEY_new_by_curve_name_ex(OPENSSL_CTX *ctx, int nid)
  37 {
  38     EC_KEY *ret = EC_KEY_new_ex(ctx);
  39     if (ret == NULL)
  40         return NULL;
  41     ret->group = EC_GROUP_new_by_curve_name_ex(ctx, nid);
  42     if (ret->group == NULL) {
  43         EC_KEY_free(ret);
  44         return NULL;
  45     }
  46     if (ret->meth->set_group != NULL
  47         && ret->meth->set_group(ret, ret->group) == 0) {
  48         EC_KEY_free(ret);
  49         return NULL;
  50     }
  51     return ret;
  52 }
  53
  54 #ifndef FIPS_MODE
  55 EC_KEY *EC_KEY_new_by_curve_name(int nid)
  56 {
  57     return EC_KEY_new_by_curve_name_ex(NULL, nid);
  58 }
  59 #endif
  60
  61 void EC_KEY_free(EC_KEY *r)
  62 {
  63     int i;
  64
  65     if (r == NULL)
  66         return;
  67
  68     CRYPTO_DOWN_REF(&r->references, &i, r->lock);
  69     REF_PRINT_COUNT("EC_KEY", r);
  70     if (i > 0)
  71         return;
  72     REF_ASSERT_ISNT(i < 0);
  73
  74     if (r->meth != NULL && r->meth->finish != NULL)
  75         r->meth->finish(r);
  76
  77 #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
  78     ENGINE_finish(r->engine);
  79 #endif
  80
  81     if (r->group && r->group->meth->keyfinish)
  82         r->group->meth->keyfinish(r);
  83
  84 #ifndef FIPS_MODE
  85     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data);
  86 #endif
  87     CRYPTO_THREAD_lock_free(r->lock);
  88     EC_GROUP_free(r->group);
  89     EC_POINT_free(r->pub_key);
  90     BN_clear_free(r->priv_key);
  91
  92     OPENSSL_clear_free((void *)r, sizeof(EC_KEY));
  93 }
  94
  95 EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src)
  96 {
  97     if (dest == NULL || src == NULL) {
  98         ECerr(EC_F_EC_KEY_COPY, ERR_R_PASSED_NULL_PARAMETER);
  99         return NULL;
 100     }
 101     if (src->meth != dest->meth) {
 102         if (dest->meth->finish != NULL)
 103             dest->meth->finish(dest);
 104         if (dest->group && dest->group->meth->keyfinish)
 105             dest->group->meth->keyfinish(dest);
 106 #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
 107         if (ENGINE_finish(dest->engine) == 0)
 108             return 0;
 109         dest->engine = NULL;
 110 #endif
 111     }
 112     dest->libctx = src->libctx;
 113     /* copy the parameters */
 114     if (src->group != NULL) {
 115         const EC_METHOD *meth = EC_GROUP_method_of(src->group);
 116         /* clear the old group */
 117         EC_GROUP_free(dest->group);
 118         dest->group = EC_GROUP_new_ex(src->libctx, meth);
 119         if (dest->group == NULL)
 120             return NULL;
 121         if (!EC_GROUP_copy(dest->group, src->group))
 122             return NULL;
 123
 124         /*  copy the public key */
 125         if (src->pub_key != NULL) {
 126             EC_POINT_free(dest->pub_key);
 127             dest->pub_key = EC_POINT_new(src->group);
 128             if (dest->pub_key == NULL)
 129                 return NULL;
 130             if (!EC_POINT_copy(dest->pub_key, src->pub_key))
 131                 return NULL;
 132         }
 133         /* copy the private key */
 134         if (src->priv_key != NULL) {
 135             if (dest->priv_key == NULL) {
 136                 dest->priv_key = BN_new();
 137                 if (dest->priv_key == NULL)
 138                     return NULL;
 139             }
 140             if (!BN_copy(dest->priv_key, src->priv_key))
 141                 return NULL;
 142             if (src->group->meth->keycopy
 143                 && src->group->meth->keycopy(dest, src) == 0)
 144                 return NULL;
 145         }
 146     }
 147
 148
 149     /* copy the rest */
 150     dest->enc_flag = src->enc_flag;
 151     dest->conv_form = src->conv_form;
 152     dest->version = src->version;
 153     dest->flags = src->flags;
 154 #ifndef FIPS_MODE
 155     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY,
 156                             &dest->ex_data, &src->ex_data))
 157         return NULL;
 158 #endif
 159
 160     if (src->meth != dest->meth) {
 161 #if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
 162         if (src->engine != NULL && ENGINE_init(src->engine) == 0)
 163             return NULL;
 164         dest->engine = src->engine;
 165 #endif
 166         dest->meth = src->meth;
 167     }
 168
 169     if (src->meth->copy != NULL && src->meth->copy(dest, src) == 0)
 170         return NULL;
 171
 172     return dest;
 173 }
 174
 175 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key)
 176 {
 177     EC_KEY *ret = ec_key_new_method_int(ec_key->libctx, ec_key->engine);
 178
 179     if (ret == NULL)
 180         return NULL;
 181
 182     if (EC_KEY_copy(ret, ec_key) == NULL) {
 183         EC_KEY_free(ret);
 184         return NULL;
 185     }
 186     return ret;
 187 }
 188
 189 int EC_KEY_up_ref(EC_KEY *r)
 190 {
 191     int i;
 192
 193     if (CRYPTO_UP_REF(&r->references, &i, r->lock) <= 0)
 194         return 0;
 195
 196     REF_PRINT_COUNT("EC_KEY", r);
 197     REF_ASSERT_ISNT(i < 2);
 198     return ((i > 1) ? 1 : 0);
 199 }
 200
 201 ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey)
 202 {
 203     return eckey->engine;
 204 }
 205
 206 int EC_KEY_generate_key(EC_KEY *eckey)
 207 {
 208     if (eckey == NULL || eckey->group == NULL) {
 209         ECerr(EC_F_EC_KEY_GENERATE_KEY, ERR_R_PASSED_NULL_PARAMETER);
 210         return 0;
 211     }
 212     if (eckey->meth->keygen != NULL)
 213         return eckey->meth->keygen(eckey);
 214     ECerr(EC_F_EC_KEY_GENERATE_KEY, EC_R_OPERATION_NOT_SUPPORTED);
 215     return 0;
 216 }
 217
 218 int ossl_ec_key_gen(EC_KEY *eckey)
 219 {
 220     return eckey->group->meth->keygen(eckey);
 221 }
 222
 223 /*
 224  * ECC Key generation.
 225  * See SP800-56AR3 5.6.1.2.2 "Key Pair Generation by Testing Candidates"
 226  *
 227  * Params:
 228  *     eckey An EC key object that contains domain params. The generated keypair
 229  *           is stored in this object.
 230  * Returns 1 if the keypair was generated or 0 otherwise.
 231  */
 232 int ec_key_simple_generate_key(EC_KEY *eckey)
 233 {
 234     int ok = 0;
 235     BIGNUM *priv_key = NULL;
 236     const BIGNUM *order = NULL;
 237     EC_POINT *pub_key = NULL;
 238     const EC_GROUP *group = eckey->group;
 239     BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx);
 240
 241     if (ctx == NULL)
 242         goto err;
 243
 244     if (eckey->priv_key == NULL) {
 245         priv_key = BN_secure_new();
 246         if (priv_key == NULL)
 247             goto err;
 248     } else
 249         priv_key = eckey->priv_key;
 250
 251     /*
 252      * Steps (1-2): Check domain parameters and security strength.
 253      * These steps must be done by the user. This would need to be
 254      * stated in the security policy.
 255      */
 256
 257     order = EC_GROUP_get0_order(group);
 258     if (order == NULL)
 259         goto err;
 260
 261     /*
 262      * Steps (3-7): priv_key = DRBG_RAND(order_n_bits) (range [1, n-1]).
 263      * Although this is slightly different from the standard, it is effectively
 264      * equivalent as it gives an unbiased result ranging from 1..n-1. It is also
 265      * faster as the standard needs to retry more often. Also doing
 266      * 1 + rand[0..n-2] would effect the way that tests feed dummy entropy into
 267      * rand so the simpler backward compatible method has been used here.
 268      */
 269     do
 270         if (!BN_priv_rand_range_ex(priv_key, order, ctx))
 271             goto err;
 272     while (BN_is_zero(priv_key)) ;
 273
 274     if (eckey->pub_key == NULL) {
 275         pub_key = EC_POINT_new(group);
 276         if (pub_key == NULL)
 277             goto err;
 278     } else
 279         pub_key = eckey->pub_key;
 280
 281     /* Step (8) : pub_key = priv_key * G (where G is a point on the curve) */
 282     if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx))
 283         goto err;
 284
 285     eckey->priv_key = priv_key;
 286     eckey->pub_key = pub_key;
 287     priv_key = NULL;
 288     pub_key = NULL;
 289
 290     ok = 1;
 291
 292 err:
 293     /* Step (9): If there is an error return an invalid keypair. */
 294     if (!ok) {
 295         BN_clear(eckey->priv_key);
 296         if (eckey->pub_key != NULL)
 297             EC_POINT_set_to_infinity(group, eckey->pub_key);
 298     }
 299
 300     EC_POINT_free(pub_key);
 301     BN_clear_free(priv_key);
 302     BN_CTX_free(ctx);
 303     return ok;
 304 }
 305
 306 int ec_key_simple_generate_public_key(EC_KEY *eckey)
 307 {
 308     /*
 309      * See SP800-56AR3 5.6.1.2.2: Step (8)
 310      * pub_key = priv_key * G (where G is a point on the curve)
 311      */
 312     return EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL,
 313                         NULL, NULL);
 314 }
 315
 316 int EC_KEY_check_key(const EC_KEY *eckey)
 317 {
 318     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 319         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 320         return 0;
 321     }
 322
 323     if (eckey->group->meth->keycheck == NULL) {
 324         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 325         return 0;
 326     }
 327
 328     return eckey->group->meth->keycheck(eckey);
 329 }
 330
 331 /*
 332  * Check the range of the EC public key.
 333  * See SP800-56A R3 Section 5.6.2.3.3 (Part 2)
 334  * i.e.
 335  *  - If q = odd prime p: Verify that xQ and yQ are integers in the
 336  *    interval[0, p - 1], OR
 337  *  - If q = 2m: Verify that xQ and yQ are bit strings of length m bits.
 338  * Returns 1 if the public key has a valid range, otherwise it returns 0.
 339  */
 340 static int ec_key_public_range_check(BN_CTX *ctx, const EC_KEY *key)
 341 {
 342     int ret = 0;
 343     BIGNUM *x, *y;
 344
 345     BN_CTX_start(ctx);
 346     x = BN_CTX_get(ctx);
 347     y = BN_CTX_get(ctx);
 348     if (y == NULL)
 349         goto err;
 350
 351     if (!EC_POINT_get_affine_coordinates(key->group, key->pub_key, x, y, ctx))
 352         goto err;
 353
 354     if (EC_METHOD_get_field_type(key->group->meth) == NID_X9_62_prime_field) {
 355         if (BN_is_negative(x)
 356             || BN_cmp(x, key->group->field) >= 0
 357             || BN_is_negative(y)
 358             || BN_cmp(y, key->group->field) >= 0) {
 359             goto err;
 360         }
 361     } else {
 362         int m = EC_GROUP_get_degree(key->group);
 363         if (BN_num_bits(x) > m || BN_num_bits(y) > m) {
 364             goto err;
 365         }
 366     }
 367     ret = 1;
 368 err:
 369     BN_CTX_end(ctx);
 370     return ret;
 371 }
 372
 373 /*
 374  * ECC Key validation as specified in SP800-56A R3.
 375  *    Section 5.6.2.3.3 ECC Full Public-Key Validation
 376  *    Section 5.6.2.1.2 Owner Assurance of Private-Key Validity
 377  *    Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
 378  * NOTES:
 379  *    Before calling this method in fips mode, there should be an assurance that
 380  *    an approved elliptic-curve group is used.
 381  * Returns 1 if the key is valid, otherwise it returns 0.
 382  */
 383 int ec_key_simple_check_key(const EC_KEY *eckey)
 384 {
 385     int ok = 0;
 386     BN_CTX *ctx = NULL;
 387     const BIGNUM *order = NULL;
 388     EC_POINT *point = NULL;
 389
 390     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 391         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 392         return 0;
 393     }
 394
 395     /* 5.6.2.3.3 (Step 1): Q != infinity */
 396     if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
 397         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_AT_INFINITY);
 398         goto err;
 399     }
 400
 401     if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL)
 402         goto err;
 403
 404     if ((point = EC_POINT_new(eckey->group)) == NULL)
 405         goto err;
 406
 407     /* 5.6.2.3.3 (Step 2) Test if the public key is in range */
 408     if (!ec_key_public_range_check(ctx, eckey)) {
 409         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_COORDINATES_OUT_OF_RANGE);
 410         goto err;
 411     }
 412
 413     /* 5.6.2.3.3 (Step 3) is the pub_key on the elliptic curve */
 414     if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
 415         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
 416         goto err;
 417     }
 418
 419     order = eckey->group->order;
 420     if (BN_is_zero(order)) {
 421         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
 422         goto err;
 423     }
 424     /* 5.6.2.3.3 (Step 4) : pub_key * order is the point at infinity. */
 425     if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
 426         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 427         goto err;
 428     }
 429     if (!EC_POINT_is_at_infinity(eckey->group, point)) {
 430         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 431         goto err;
 432     }
 433
 434     if (eckey->priv_key != NULL) {
 435         /*
 436          * 5.6.2.1.2 Owner Assurance of Private-Key Validity
 437          * The private key is in the range [1, order-1]
 438          */
 439         if (BN_cmp(eckey->priv_key, BN_value_one()) < 0
 440                 || BN_cmp(eckey->priv_key, order) >= 0) {
 441             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 442             goto err;
 443         }
 444         /*
 445          * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency (b)
 446          * Check if generator * priv_key = pub_key
 447          */
 448         if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
 449                           NULL, NULL, ctx)) {
 450             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 451             goto err;
 452         }
 453         if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
 454             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
 455             goto err;
 456         }
 457     }
 458     ok = 1;
 459  err:
 460     BN_CTX_free(ctx);
 461     EC_POINT_free(point);
 462     return ok;
 463 }
 464
 465 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
 466                                              BIGNUM *y)
 467 {
 468     BN_CTX *ctx = NULL;
 469     BIGNUM *tx, *ty;
 470     EC_POINT *point = NULL;
 471     int ok = 0;
 472
 473     if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
 474         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 475               ERR_R_PASSED_NULL_PARAMETER);
 476         return 0;
 477     }
 478     ctx = BN_CTX_new_ex(key->libctx);
 479     if (ctx == NULL)
 480         return 0;
 481
 482     BN_CTX_start(ctx);
 483     point = EC_POINT_new(key->group);
 484
 485     if (point == NULL)
 486         goto err;
 487
 488     tx = BN_CTX_get(ctx);
 489     ty = BN_CTX_get(ctx);
 490     if (ty == NULL)
 491         goto err;
 492
 493     if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx))
 494         goto err;
 495     if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx))
 496         goto err;
 497
 498     /*
 499      * Check if retrieved coordinates match originals. The range check is done
 500      * inside EC_KEY_check_key().
 501      */
 502     if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
 503         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 504               EC_R_COORDINATES_OUT_OF_RANGE);
 505         goto err;
 506     }
 507
 508     if (!EC_KEY_set_public_key(key, point))
 509         goto err;
 510
 511     if (EC_KEY_check_key(key) == 0)
 512         goto err;
 513
 514     ok = 1;
 515
 516  err:
 517     BN_CTX_end(ctx);
 518     BN_CTX_free(ctx);
 519     EC_POINT_free(point);
 520     return ok;
 521
 522 }
 523
 524 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
 525 {
 526     return key->group;
 527 }
 528
 529 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
 530 {
 531     if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
 532         return 0;
 533     EC_GROUP_free(key->group);
 534     key->group = EC_GROUP_dup(group);
 535     return (key->group == NULL) ? 0 : 1;
 536 }
 537
 538 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
 539 {
 540     return key->priv_key;
 541 }
 542
 543 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
 544 {
 545     if (key->group == NULL || key->group->meth == NULL)
 546         return 0;
 547     if (key->group->meth->set_private != NULL
 548         && key->group->meth->set_private(key, priv_key) == 0)
 549         return 0;
 550     if (key->meth->set_private != NULL
 551         && key->meth->set_private(key, priv_key) == 0)
 552         return 0;
 553     BN_clear_free(key->priv_key);
 554     key->priv_key = BN_dup(priv_key);
 555     return (key->priv_key == NULL) ? 0 : 1;
 556 }
 557
 558 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
 559 {
 560     return key->pub_key;
 561 }
 562
 563 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
 564 {
 565     if (key->meth->set_public != NULL
 566         && key->meth->set_public(key, pub_key) == 0)
 567         return 0;
 568     EC_POINT_free(key->pub_key);
 569     key->pub_key = EC_POINT_dup(pub_key, key->group);
 570     return (key->pub_key == NULL) ? 0 : 1;
 571 }
 572
 573 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
 574 {
 575     return key->enc_flag;
 576 }
 577
 578 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
 579 {
 580     key->enc_flag = flags;
 581 }
 582
 583 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
 584 {
 585     return key->conv_form;
 586 }
 587
 588 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
 589 {
 590     key->conv_form = cform;
 591     if (key->group != NULL)
 592         EC_GROUP_set_point_conversion_form(key->group, cform);
 593 }
 594
 595 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
 596 {
 597     if (key->group != NULL)
 598         EC_GROUP_set_asn1_flag(key->group, flag);
 599 }
 600
 601 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
 602 {
 603     if (key->group == NULL)
 604         return 0;
 605     return EC_GROUP_precompute_mult(key->group, ctx);
 606 }
 607
 608 int EC_KEY_get_flags(const EC_KEY *key)
 609 {
 610     return key->flags;
 611 }
 612
 613 void EC_KEY_set_flags(EC_KEY *key, int flags)
 614 {
 615     key->flags |= flags;
 616 }
 617
 618 void EC_KEY_clear_flags(EC_KEY *key, int flags)
 619 {
 620     key->flags &= ~flags;
 621 }
 622
 623 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
 624                         unsigned char **pbuf, BN_CTX *ctx)
 625 {
 626     if (key == NULL || key->pub_key == NULL || key->group == NULL)
 627         return 0;
 628     return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
 629 }
 630
 631 int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
 632                    BN_CTX *ctx)
 633 {
 634     if (key == NULL || key->group == NULL)
 635         return 0;
 636     if (key->pub_key == NULL)
 637         key->pub_key = EC_POINT_new(key->group);
 638     if (key->pub_key == NULL)
 639         return 0;
 640     if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0)
 641         return 0;
 642     /*
 643      * Save the point conversion form.
 644      * For non-custom curves the first octet of the buffer (excluding
 645      * the last significant bit) contains the point conversion form.
 646      * EC_POINT_oct2point() has already performed sanity checking of
 647      * the buffer so we know it is valid.
 648      */
 649     if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0)
 650         key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01);
 651     return 1;
 652 }
 653
 654 size_t EC_KEY_priv2oct(const EC_KEY *eckey,
 655                        unsigned char *buf, size_t len)
 656 {
 657     if (eckey->group == NULL || eckey->group->meth == NULL)
 658         return 0;
 659     if (eckey->group->meth->priv2oct == NULL) {
 660         ECerr(EC_F_EC_KEY_PRIV2OCT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 661         return 0;
 662     }
 663
 664     return eckey->group->meth->priv2oct(eckey, buf, len);
 665 }
 666
 667 size_t ec_key_simple_priv2oct(const EC_KEY *eckey,
 668                               unsigned char *buf, size_t len)
 669 {
 670     size_t buf_len;
 671
 672     buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8;
 673     if (eckey->priv_key == NULL)
 674         return 0;
 675     if (buf == NULL)
 676         return buf_len;
 677     else if (len < buf_len)
 678         return 0;
 679
 680     /* Octetstring may need leading zeros if BN is to short */
 681
 682     if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) {
 683         ECerr(EC_F_EC_KEY_SIMPLE_PRIV2OCT, EC_R_BUFFER_TOO_SMALL);
 684         return 0;
 685     }
 686
 687     return buf_len;
 688 }
 689
 690 int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 691 {
 692     if (eckey->group == NULL || eckey->group->meth == NULL)
 693         return 0;
 694     if (eckey->group->meth->oct2priv == NULL) {
 695         ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 696         return 0;
 697     }
 698     return eckey->group->meth->oct2priv(eckey, buf, len);
 699 }
 700
 701 int ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 702 {
 703     if (eckey->priv_key == NULL)
 704         eckey->priv_key = BN_secure_new();
 705     if (eckey->priv_key == NULL) {
 706         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_MALLOC_FAILURE);
 707         return 0;
 708     }
 709     eckey->priv_key = BN_bin2bn(buf, len, eckey->priv_key);
 710     if (eckey->priv_key == NULL) {
 711         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_BN_LIB);
 712         return 0;
 713     }
 714     return 1;
 715 }
 716
 717 size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf)
 718 {
 719     size_t len;
 720     unsigned char *buf;
 721
 722     len = EC_KEY_priv2oct(eckey, NULL, 0);
 723     if (len == 0)
 724         return 0;
 725     if ((buf = OPENSSL_malloc(len)) == NULL) {
 726         ECerr(EC_F_EC_KEY_PRIV2BUF, ERR_R_MALLOC_FAILURE);
 727         return 0;
 728     }
 729     len = EC_KEY_priv2oct(eckey, buf, len);
 730     if (len == 0) {
 731         OPENSSL_free(buf);
 732         return 0;
 733     }
 734     *pbuf = buf;
 735     return len;
 736 }
 737
 738 int EC_KEY_can_sign(const EC_KEY *eckey)
 739 {
 740     if (eckey->group == NULL || eckey->group->meth == NULL
 741         || (eckey->group->meth->flags & EC_FLAGS_NO_SIGN))
 742         return 0;
 743     return 1;
 744 }