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