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