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     dest->dirty_cnt++;
 173
 174     return dest;
 175 }
 176
 177 EC_KEY *EC_KEY_dup(const EC_KEY *ec_key)
 178 {
 179     EC_KEY *ret = ec_key_new_method_int(ec_key->libctx, ec_key->engine);
 180
 181     if (ret == NULL)
 182         return NULL;
 183
 184     if (EC_KEY_copy(ret, ec_key) == NULL) {
 185         EC_KEY_free(ret);
 186         return NULL;
 187     }
 188     return ret;
 189 }
 190
 191 int EC_KEY_up_ref(EC_KEY *r)
 192 {
 193     int i;
 194
 195     if (CRYPTO_UP_REF(&r->references, &i, r->lock) <= 0)
 196         return 0;
 197
 198     REF_PRINT_COUNT("EC_KEY", r);
 199     REF_ASSERT_ISNT(i < 2);
 200     return ((i > 1) ? 1 : 0);
 201 }
 202
 203 ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey)
 204 {
 205     return eckey->engine;
 206 }
 207
 208 int EC_KEY_generate_key(EC_KEY *eckey)
 209 {
 210     if (eckey == NULL || eckey->group == NULL) {
 211         ECerr(EC_F_EC_KEY_GENERATE_KEY, ERR_R_PASSED_NULL_PARAMETER);
 212         return 0;
 213     }
 214     if (eckey->meth->keygen != NULL) {
 215         int ret;
 216
 217         ret = eckey->meth->keygen(eckey);
 218         if (ret == 1)
 219             eckey->dirty_cnt++;
 220
 221         return ret;
 222     }
 223     ECerr(EC_F_EC_KEY_GENERATE_KEY, EC_R_OPERATION_NOT_SUPPORTED);
 224     return 0;
 225 }
 226
 227 int ossl_ec_key_gen(EC_KEY *eckey)
 228 {
 229     int ret;
 230
 231     ret = eckey->group->meth->keygen(eckey);
 232
 233     if (ret == 1)
 234         eckey->dirty_cnt++;
 235     return ret;
 236 }
 237
 238 /*
 239  * ECC Key generation.
 240  * See SP800-56AR3 5.6.1.2.2 "Key Pair Generation by Testing Candidates"
 241  *
 242  * Params:
 243  *     eckey An EC key object that contains domain params. The generated keypair
 244  *           is stored in this object.
 245  * Returns 1 if the keypair was generated or 0 otherwise.
 246  */
 247 int ec_key_simple_generate_key(EC_KEY *eckey)
 248 {
 249     int ok = 0;
 250     BIGNUM *priv_key = NULL;
 251     const BIGNUM *order = NULL;
 252     EC_POINT *pub_key = NULL;
 253     const EC_GROUP *group = eckey->group;
 254     BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx);
 255
 256     if (ctx == NULL)
 257         goto err;
 258
 259     if (eckey->priv_key == NULL) {
 260         priv_key = BN_secure_new();
 261         if (priv_key == NULL)
 262             goto err;
 263     } else
 264         priv_key = eckey->priv_key;
 265
 266     /*
 267      * Steps (1-2): Check domain parameters and security strength.
 268      * These steps must be done by the user. This would need to be
 269      * stated in the security policy.
 270      */
 271
 272     order = EC_GROUP_get0_order(group);
 273     if (order == NULL)
 274         goto err;
 275
 276     /*
 277      * Steps (3-7): priv_key = DRBG_RAND(order_n_bits) (range [1, n-1]).
 278      * Although this is slightly different from the standard, it is effectively
 279      * equivalent as it gives an unbiased result ranging from 1..n-1. It is also
 280      * faster as the standard needs to retry more often. Also doing
 281      * 1 + rand[0..n-2] would effect the way that tests feed dummy entropy into
 282      * rand so the simpler backward compatible method has been used here.
 283      */
 284     do
 285         if (!BN_priv_rand_range_ex(priv_key, order, ctx))
 286             goto err;
 287     while (BN_is_zero(priv_key)) ;
 288
 289     if (eckey->pub_key == NULL) {
 290         pub_key = EC_POINT_new(group);
 291         if (pub_key == NULL)
 292             goto err;
 293     } else
 294         pub_key = eckey->pub_key;
 295
 296     /* Step (8) : pub_key = priv_key * G (where G is a point on the curve) */
 297     if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx))
 298         goto err;
 299
 300     eckey->priv_key = priv_key;
 301     eckey->pub_key = pub_key;
 302     priv_key = NULL;
 303     pub_key = NULL;
 304
 305     eckey->dirty_cnt++;
 306
 307     ok = 1;
 308
 309 err:
 310     /* Step (9): If there is an error return an invalid keypair. */
 311     if (!ok) {
 312         BN_clear(eckey->priv_key);
 313         if (eckey->pub_key != NULL)
 314             EC_POINT_set_to_infinity(group, eckey->pub_key);
 315     }
 316
 317     EC_POINT_free(pub_key);
 318     BN_clear_free(priv_key);
 319     BN_CTX_free(ctx);
 320     return ok;
 321 }
 322
 323 int ec_key_simple_generate_public_key(EC_KEY *eckey)
 324 {
 325     int ret;
 326
 327     /*
 328      * See SP800-56AR3 5.6.1.2.2: Step (8)
 329      * pub_key = priv_key * G (where G is a point on the curve)
 330      */
 331     ret = EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL,
 332                        NULL, NULL);
 333
 334     if (ret == 1)
 335         eckey->dirty_cnt++;
 336
 337     return ret;
 338 }
 339
 340 int EC_KEY_check_key(const EC_KEY *eckey)
 341 {
 342     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 343         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 344         return 0;
 345     }
 346
 347     if (eckey->group->meth->keycheck == NULL) {
 348         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 349         return 0;
 350     }
 351
 352     return eckey->group->meth->keycheck(eckey);
 353 }
 354
 355 /*
 356  * Check the range of the EC public key.
 357  * See SP800-56A R3 Section 5.6.2.3.3 (Part 2)
 358  * i.e.
 359  *  - If q = odd prime p: Verify that xQ and yQ are integers in the
 360  *    interval[0, p - 1], OR
 361  *  - If q = 2m: Verify that xQ and yQ are bit strings of length m bits.
 362  * Returns 1 if the public key has a valid range, otherwise it returns 0.
 363  */
 364 static int ec_key_public_range_check(BN_CTX *ctx, const EC_KEY *key)
 365 {
 366     int ret = 0;
 367     BIGNUM *x, *y;
 368
 369     BN_CTX_start(ctx);
 370     x = BN_CTX_get(ctx);
 371     y = BN_CTX_get(ctx);
 372     if (y == NULL)
 373         goto err;
 374
 375     if (!EC_POINT_get_affine_coordinates(key->group, key->pub_key, x, y, ctx))
 376         goto err;
 377
 378     if (EC_METHOD_get_field_type(key->group->meth) == NID_X9_62_prime_field) {
 379         if (BN_is_negative(x)
 380             || BN_cmp(x, key->group->field) >= 0
 381             || BN_is_negative(y)
 382             || BN_cmp(y, key->group->field) >= 0) {
 383             goto err;
 384         }
 385     } else {
 386         int m = EC_GROUP_get_degree(key->group);
 387         if (BN_num_bits(x) > m || BN_num_bits(y) > m) {
 388             goto err;
 389         }
 390     }
 391     ret = 1;
 392 err:
 393     BN_CTX_end(ctx);
 394     return ret;
 395 }
 396
 397 /*
 398  * ECC Key validation as specified in SP800-56A R3.
 399  *    Section 5.6.2.3.3 ECC Full Public-Key Validation
 400  *    Section 5.6.2.1.2 Owner Assurance of Private-Key Validity
 401  *    Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
 402  * NOTES:
 403  *    Before calling this method in fips mode, there should be an assurance that
 404  *    an approved elliptic-curve group is used.
 405  * Returns 1 if the key is valid, otherwise it returns 0.
 406  */
 407 int ec_key_simple_check_key(const EC_KEY *eckey)
 408 {
 409     int ok = 0;
 410     BN_CTX *ctx = NULL;
 411     const BIGNUM *order = NULL;
 412     EC_POINT *point = NULL;
 413
 414     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 415         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 416         return 0;
 417     }
 418
 419     /* 5.6.2.3.3 (Step 1): Q != infinity */
 420     if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
 421         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_AT_INFINITY);
 422         goto err;
 423     }
 424
 425     if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL)
 426         goto err;
 427
 428     if ((point = EC_POINT_new(eckey->group)) == NULL)
 429         goto err;
 430
 431     /* 5.6.2.3.3 (Step 2) Test if the public key is in range */
 432     if (!ec_key_public_range_check(ctx, eckey)) {
 433         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_COORDINATES_OUT_OF_RANGE);
 434         goto err;
 435     }
 436
 437     /* 5.6.2.3.3 (Step 3) is the pub_key on the elliptic curve */
 438     if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
 439         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
 440         goto err;
 441     }
 442
 443     order = eckey->group->order;
 444     if (BN_is_zero(order)) {
 445         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
 446         goto err;
 447     }
 448     /* 5.6.2.3.3 (Step 4) : pub_key * order is the point at infinity. */
 449     if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
 450         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 451         goto err;
 452     }
 453     if (!EC_POINT_is_at_infinity(eckey->group, point)) {
 454         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 455         goto err;
 456     }
 457
 458     if (eckey->priv_key != NULL) {
 459         /*
 460          * 5.6.2.1.2 Owner Assurance of Private-Key Validity
 461          * The private key is in the range [1, order-1]
 462          */
 463         if (BN_cmp(eckey->priv_key, BN_value_one()) < 0
 464                 || BN_cmp(eckey->priv_key, order) >= 0) {
 465             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 466             goto err;
 467         }
 468         /*
 469          * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency (b)
 470          * Check if generator * priv_key = pub_key
 471          */
 472         if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
 473                           NULL, NULL, ctx)) {
 474             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 475             goto err;
 476         }
 477         if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
 478             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
 479             goto err;
 480         }
 481     }
 482     ok = 1;
 483  err:
 484     BN_CTX_free(ctx);
 485     EC_POINT_free(point);
 486     return ok;
 487 }
 488
 489 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
 490                                              BIGNUM *y)
 491 {
 492     BN_CTX *ctx = NULL;
 493     BIGNUM *tx, *ty;
 494     EC_POINT *point = NULL;
 495     int ok = 0;
 496
 497     if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
 498         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 499               ERR_R_PASSED_NULL_PARAMETER);
 500         return 0;
 501     }
 502     ctx = BN_CTX_new_ex(key->libctx);
 503     if (ctx == NULL)
 504         return 0;
 505
 506     BN_CTX_start(ctx);
 507     point = EC_POINT_new(key->group);
 508
 509     if (point == NULL)
 510         goto err;
 511
 512     tx = BN_CTX_get(ctx);
 513     ty = BN_CTX_get(ctx);
 514     if (ty == NULL)
 515         goto err;
 516
 517     if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx))
 518         goto err;
 519     if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx))
 520         goto err;
 521
 522     /*
 523      * Check if retrieved coordinates match originals. The range check is done
 524      * inside EC_KEY_check_key().
 525      */
 526     if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
 527         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 528               EC_R_COORDINATES_OUT_OF_RANGE);
 529         goto err;
 530     }
 531
 532     /* EC_KEY_set_public_key updates dirty_cnt */
 533     if (!EC_KEY_set_public_key(key, point))
 534         goto err;
 535
 536     if (EC_KEY_check_key(key) == 0)
 537         goto err;
 538
 539     ok = 1;
 540
 541  err:
 542     BN_CTX_end(ctx);
 543     BN_CTX_free(ctx);
 544     EC_POINT_free(point);
 545     return ok;
 546
 547 }
 548
 549 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
 550 {
 551     return key->group;
 552 }
 553
 554 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
 555 {
 556     if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
 557         return 0;
 558     EC_GROUP_free(key->group);
 559     key->group = EC_GROUP_dup(group);
 560     key->dirty_cnt++;
 561     return (key->group == NULL) ? 0 : 1;
 562 }
 563
 564 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
 565 {
 566     return key->priv_key;
 567 }
 568
 569 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
 570 {
 571     if (key->group == NULL || key->group->meth == NULL)
 572         return 0;
 573     if (key->group->meth->set_private != NULL
 574         && key->group->meth->set_private(key, priv_key) == 0)
 575         return 0;
 576     if (key->meth->set_private != NULL
 577         && key->meth->set_private(key, priv_key) == 0)
 578         return 0;
 579     BN_clear_free(key->priv_key);
 580     key->priv_key = BN_dup(priv_key);
 581     key->dirty_cnt++;
 582     return (key->priv_key == NULL) ? 0 : 1;
 583 }
 584
 585 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
 586 {
 587     return key->pub_key;
 588 }
 589
 590 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
 591 {
 592     if (key->meth->set_public != NULL
 593         && key->meth->set_public(key, pub_key) == 0)
 594         return 0;
 595     EC_POINT_free(key->pub_key);
 596     key->pub_key = EC_POINT_dup(pub_key, key->group);
 597     key->dirty_cnt++;
 598     return (key->pub_key == NULL) ? 0 : 1;
 599 }
 600
 601 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
 602 {
 603     return key->enc_flag;
 604 }
 605
 606 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
 607 {
 608     key->enc_flag = flags;
 609 }
 610
 611 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
 612 {
 613     return key->conv_form;
 614 }
 615
 616 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
 617 {
 618     key->conv_form = cform;
 619     if (key->group != NULL)
 620         EC_GROUP_set_point_conversion_form(key->group, cform);
 621 }
 622
 623 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
 624 {
 625     if (key->group != NULL)
 626         EC_GROUP_set_asn1_flag(key->group, flag);
 627 }
 628
 629 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
 630 {
 631     if (key->group == NULL)
 632         return 0;
 633     return EC_GROUP_precompute_mult(key->group, ctx);
 634 }
 635
 636 int EC_KEY_get_flags(const EC_KEY *key)
 637 {
 638     return key->flags;
 639 }
 640
 641 void EC_KEY_set_flags(EC_KEY *key, int flags)
 642 {
 643     key->flags |= flags;
 644     key->dirty_cnt++;
 645 }
 646
 647 void EC_KEY_clear_flags(EC_KEY *key, int flags)
 648 {
 649     key->flags &= ~flags;
 650     key->dirty_cnt++;
 651 }
 652
 653 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
 654                         unsigned char **pbuf, BN_CTX *ctx)
 655 {
 656     if (key == NULL || key->pub_key == NULL || key->group == NULL)
 657         return 0;
 658     return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
 659 }
 660
 661 int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
 662                    BN_CTX *ctx)
 663 {
 664     if (key == NULL || key->group == NULL)
 665         return 0;
 666     if (key->pub_key == NULL)
 667         key->pub_key = EC_POINT_new(key->group);
 668     if (key->pub_key == NULL)
 669         return 0;
 670     if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0)
 671         return 0;
 672     key->dirty_cnt++;
 673     /*
 674      * Save the point conversion form.
 675      * For non-custom curves the first octet of the buffer (excluding
 676      * the last significant bit) contains the point conversion form.
 677      * EC_POINT_oct2point() has already performed sanity checking of
 678      * the buffer so we know it is valid.
 679      */
 680     if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0)
 681         key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01);
 682     return 1;
 683 }
 684
 685 size_t EC_KEY_priv2oct(const EC_KEY *eckey,
 686                        unsigned char *buf, size_t len)
 687 {
 688     if (eckey->group == NULL || eckey->group->meth == NULL)
 689         return 0;
 690     if (eckey->group->meth->priv2oct == NULL) {
 691         ECerr(EC_F_EC_KEY_PRIV2OCT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 692         return 0;
 693     }
 694
 695     return eckey->group->meth->priv2oct(eckey, buf, len);
 696 }
 697
 698 size_t ec_key_simple_priv2oct(const EC_KEY *eckey,
 699                               unsigned char *buf, size_t len)
 700 {
 701     size_t buf_len;
 702
 703     buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8;
 704     if (eckey->priv_key == NULL)
 705         return 0;
 706     if (buf == NULL)
 707         return buf_len;
 708     else if (len < buf_len)
 709         return 0;
 710
 711     /* Octetstring may need leading zeros if BN is to short */
 712
 713     if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) {
 714         ECerr(EC_F_EC_KEY_SIMPLE_PRIV2OCT, EC_R_BUFFER_TOO_SMALL);
 715         return 0;
 716     }
 717
 718     return buf_len;
 719 }
 720
 721 int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 722 {
 723     int ret;
 724
 725     if (eckey->group == NULL || eckey->group->meth == NULL)
 726         return 0;
 727     if (eckey->group->meth->oct2priv == NULL) {
 728         ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 729         return 0;
 730     }
 731     ret = eckey->group->meth->oct2priv(eckey, buf, len);
 732     if (ret == 1)
 733         eckey->dirty_cnt++;
 734     return ret;
 735 }
 736
 737 int ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 738 {
 739     if (eckey->priv_key == NULL)
 740         eckey->priv_key = BN_secure_new();
 741     if (eckey->priv_key == NULL) {
 742         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_MALLOC_FAILURE);
 743         return 0;
 744     }
 745     eckey->priv_key = BN_bin2bn(buf, len, eckey->priv_key);
 746     if (eckey->priv_key == NULL) {
 747         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_BN_LIB);
 748         return 0;
 749     }
 750     eckey->dirty_cnt++;
 751     return 1;
 752 }
 753
 754 size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf)
 755 {
 756     size_t len;
 757     unsigned char *buf;
 758
 759     len = EC_KEY_priv2oct(eckey, NULL, 0);
 760     if (len == 0)
 761         return 0;
 762     if ((buf = OPENSSL_malloc(len)) == NULL) {
 763         ECerr(EC_F_EC_KEY_PRIV2BUF, ERR_R_MALLOC_FAILURE);
 764         return 0;
 765     }
 766     len = EC_KEY_priv2oct(eckey, buf, len);
 767     if (len == 0) {
 768         OPENSSL_free(buf);
 769         return 0;
 770     }
 771     *pbuf = buf;
 772     return len;
 773 }
 774
 775 int EC_KEY_can_sign(const EC_KEY *eckey)
 776 {
 777     if (eckey->group == NULL || eckey->group->meth == NULL
 778         || (eckey->group->meth->flags & EC_FLAGS_NO_SIGN))
 779         return 0;
 780     return 1;
 781 }