crypto/ec/ec_key.c

   1 /*
   2  * Copyright 2002-2017 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
   4  *
   5  * Licensed under the OpenSSL license (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 "e_os.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->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 int ec_key_simple_generate_key(EC_KEY *eckey)
 199 {
 200     int ok = 0;
 201     BN_CTX *ctx = NULL;
 202     BIGNUM *priv_key = NULL;
 203     const BIGNUM *order = NULL;
 204     EC_POINT *pub_key = NULL;
 205
 206     if ((ctx = BN_CTX_new()) == NULL)
 207         goto err;
 208
 209     if (eckey->priv_key == NULL) {
 210         priv_key = BN_new();
 211         if (priv_key == NULL)
 212             goto err;
 213     } else
 214         priv_key = eckey->priv_key;
 215
 216     order = EC_GROUP_get0_order(eckey->group);
 217     if (order == NULL)
 218         goto err;
 219
 220     do
 221         if (!BN_priv_rand_range(priv_key, order))
 222             goto err;
 223     while (BN_is_zero(priv_key)) ;
 224
 225     if (eckey->pub_key == NULL) {
 226         pub_key = EC_POINT_new(eckey->group);
 227         if (pub_key == NULL)
 228             goto err;
 229     } else
 230         pub_key = eckey->pub_key;
 231
 232     if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx))
 233         goto err;
 234
 235     eckey->priv_key = priv_key;
 236     eckey->pub_key = pub_key;
 237
 238     ok = 1;
 239
 240  err:
 241     if (eckey->pub_key == NULL)
 242         EC_POINT_free(pub_key);
 243     if (eckey->priv_key != priv_key)
 244         BN_free(priv_key);
 245     BN_CTX_free(ctx);
 246     return ok;
 247 }
 248
 249 int ec_key_simple_generate_public_key(EC_KEY *eckey)
 250 {
 251     return EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL,
 252                         NULL, NULL);
 253 }
 254
 255 int EC_KEY_check_key(const EC_KEY *eckey)
 256 {
 257     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 258         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 259         return 0;
 260     }
 261
 262     if (eckey->group->meth->keycheck == NULL) {
 263         ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 264         return 0;
 265     }
 266
 267     return eckey->group->meth->keycheck(eckey);
 268 }
 269
 270 int ec_key_simple_check_key(const EC_KEY *eckey)
 271 {
 272     int ok = 0;
 273     BN_CTX *ctx = NULL;
 274     const BIGNUM *order = NULL;
 275     EC_POINT *point = NULL;
 276
 277     if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
 278         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
 279         return 0;
 280     }
 281
 282     if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
 283         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_AT_INFINITY);
 284         goto err;
 285     }
 286
 287     if ((ctx = BN_CTX_new()) == NULL)
 288         goto err;
 289     if ((point = EC_POINT_new(eckey->group)) == NULL)
 290         goto err;
 291
 292     /* testing whether the pub_key is on the elliptic curve */
 293     if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
 294         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
 295         goto err;
 296     }
 297     /* testing whether pub_key * order is the point at infinity */
 298     order = eckey->group->order;
 299     if (BN_is_zero(order)) {
 300         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
 301         goto err;
 302     }
 303     if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
 304         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 305         goto err;
 306     }
 307     if (!EC_POINT_is_at_infinity(eckey->group, point)) {
 308         ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 309         goto err;
 310     }
 311     /*
 312      * in case the priv_key is present : check if generator * priv_key ==
 313      * pub_key
 314      */
 315     if (eckey->priv_key != NULL) {
 316         if (BN_cmp(eckey->priv_key, order) >= 0) {
 317             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
 318             goto err;
 319         }
 320         if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
 321                           NULL, NULL, ctx)) {
 322             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
 323             goto err;
 324         }
 325         if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
 326             ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
 327             goto err;
 328         }
 329     }
 330     ok = 1;
 331  err:
 332     BN_CTX_free(ctx);
 333     EC_POINT_free(point);
 334     return ok;
 335 }
 336
 337 int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
 338                                              BIGNUM *y)
 339 {
 340     BN_CTX *ctx = NULL;
 341     BIGNUM *tx, *ty;
 342     EC_POINT *point = NULL;
 343     int ok = 0;
 344 #ifndef OPENSSL_NO_EC2M
 345     int tmp_nid, is_char_two = 0;
 346 #endif
 347
 348     if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
 349         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 350               ERR_R_PASSED_NULL_PARAMETER);
 351         return 0;
 352     }
 353     ctx = BN_CTX_new();
 354     if (ctx == NULL)
 355         return 0;
 356
 357     BN_CTX_start(ctx);
 358     point = EC_POINT_new(key->group);
 359
 360     if (point == NULL)
 361         goto err;
 362
 363     tx = BN_CTX_get(ctx);
 364     ty = BN_CTX_get(ctx);
 365     if (ty == NULL)
 366         goto err;
 367
 368 #ifndef OPENSSL_NO_EC2M
 369     tmp_nid = EC_METHOD_get_field_type(EC_GROUP_method_of(key->group));
 370
 371     if (tmp_nid == NID_X9_62_characteristic_two_field)
 372         is_char_two = 1;
 373
 374     if (is_char_two) {
 375         if (!EC_POINT_set_affine_coordinates_GF2m(key->group, point,
 376                                                   x, y, ctx))
 377             goto err;
 378         if (!EC_POINT_get_affine_coordinates_GF2m(key->group, point,
 379                                                   tx, ty, ctx))
 380             goto err;
 381     } else
 382 #endif
 383     {
 384         if (!EC_POINT_set_affine_coordinates_GFp(key->group, point,
 385                                                  x, y, ctx))
 386             goto err;
 387         if (!EC_POINT_get_affine_coordinates_GFp(key->group, point,
 388                                                  tx, ty, ctx))
 389             goto err;
 390     }
 391     /*
 392      * Check if retrieved coordinates match originals and are less than field
 393      * order: if not values are out of range.
 394      */
 395     if (BN_cmp(x, tx) || BN_cmp(y, ty)
 396         || (BN_cmp(x, key->group->field) >= 0)
 397         || (BN_cmp(y, key->group->field) >= 0)) {
 398         ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
 399               EC_R_COORDINATES_OUT_OF_RANGE);
 400         goto err;
 401     }
 402
 403     if (!EC_KEY_set_public_key(key, point))
 404         goto err;
 405
 406     if (EC_KEY_check_key(key) == 0)
 407         goto err;
 408
 409     ok = 1;
 410
 411  err:
 412     BN_CTX_end(ctx);
 413     BN_CTX_free(ctx);
 414     EC_POINT_free(point);
 415     return ok;
 416
 417 }
 418
 419 const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
 420 {
 421     return key->group;
 422 }
 423
 424 int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
 425 {
 426     if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
 427         return 0;
 428     EC_GROUP_free(key->group);
 429     key->group = EC_GROUP_dup(group);
 430     return (key->group == NULL) ? 0 : 1;
 431 }
 432
 433 const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
 434 {
 435     return key->priv_key;
 436 }
 437
 438 int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
 439 {
 440     if (key->group == NULL || key->group->meth == NULL)
 441         return 0;
 442     if (key->group->meth->set_private != NULL
 443         && key->group->meth->set_private(key, priv_key) == 0)
 444         return 0;
 445     if (key->meth->set_private != NULL
 446         && key->meth->set_private(key, priv_key) == 0)
 447         return 0;
 448     BN_clear_free(key->priv_key);
 449     key->priv_key = BN_dup(priv_key);
 450     return (key->priv_key == NULL) ? 0 : 1;
 451 }
 452
 453 const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
 454 {
 455     return key->pub_key;
 456 }
 457
 458 int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
 459 {
 460     if (key->meth->set_public != NULL
 461         && key->meth->set_public(key, pub_key) == 0)
 462         return 0;
 463     EC_POINT_free(key->pub_key);
 464     key->pub_key = EC_POINT_dup(pub_key, key->group);
 465     return (key->pub_key == NULL) ? 0 : 1;
 466 }
 467
 468 unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
 469 {
 470     return key->enc_flag;
 471 }
 472
 473 void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
 474 {
 475     key->enc_flag = flags;
 476 }
 477
 478 point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
 479 {
 480     return key->conv_form;
 481 }
 482
 483 void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
 484 {
 485     key->conv_form = cform;
 486     if (key->group != NULL)
 487         EC_GROUP_set_point_conversion_form(key->group, cform);
 488 }
 489
 490 void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
 491 {
 492     if (key->group != NULL)
 493         EC_GROUP_set_asn1_flag(key->group, flag);
 494 }
 495
 496 int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
 497 {
 498     if (key->group == NULL)
 499         return 0;
 500     return EC_GROUP_precompute_mult(key->group, ctx);
 501 }
 502
 503 int EC_KEY_get_flags(const EC_KEY *key)
 504 {
 505     return key->flags;
 506 }
 507
 508 void EC_KEY_set_flags(EC_KEY *key, int flags)
 509 {
 510     key->flags |= flags;
 511 }
 512
 513 void EC_KEY_clear_flags(EC_KEY *key, int flags)
 514 {
 515     key->flags &= ~flags;
 516 }
 517
 518 size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
 519                         unsigned char **pbuf, BN_CTX *ctx)
 520 {
 521     if (key == NULL || key->pub_key == NULL || key->group == NULL)
 522         return 0;
 523     return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
 524 }
 525
 526 int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
 527                    BN_CTX *ctx)
 528 {
 529     if (key == NULL || key->group == NULL)
 530         return 0;
 531     if (key->pub_key == NULL)
 532         key->pub_key = EC_POINT_new(key->group);
 533     if (key->pub_key == NULL)
 534         return 0;
 535     if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0)
 536         return 0;
 537     /*
 538      * Save the point conversion form.
 539      * For non-custom curves the first octet of the buffer (excluding
 540      * the last significant bit) contains the point conversion form.
 541      * EC_POINT_oct2point() has already performed sanity checking of
 542      * the buffer so we know it is valid.
 543      */
 544     if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0)
 545         key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01);
 546     return 1;
 547 }
 548
 549 size_t EC_KEY_priv2oct(const EC_KEY *eckey,
 550                        unsigned char *buf, size_t len)
 551 {
 552     if (eckey->group == NULL || eckey->group->meth == NULL)
 553         return 0;
 554     if (eckey->group->meth->priv2oct == NULL) {
 555         ECerr(EC_F_EC_KEY_PRIV2OCT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 556         return 0;
 557     }
 558
 559     return eckey->group->meth->priv2oct(eckey, buf, len);
 560 }
 561
 562 size_t ec_key_simple_priv2oct(const EC_KEY *eckey,
 563                               unsigned char *buf, size_t len)
 564 {
 565     size_t buf_len;
 566
 567     buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8;
 568     if (eckey->priv_key == NULL)
 569         return 0;
 570     if (buf == NULL)
 571         return buf_len;
 572     else if (len < buf_len)
 573         return 0;
 574
 575     /* Octetstring may need leading zeros if BN is to short */
 576
 577     if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) {
 578         ECerr(EC_F_EC_KEY_SIMPLE_PRIV2OCT, EC_R_BUFFER_TOO_SMALL);
 579         return 0;
 580     }
 581
 582     return buf_len;
 583 }
 584
 585 int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 586 {
 587     if (eckey->group == NULL || eckey->group->meth == NULL)
 588         return 0;
 589     if (eckey->group->meth->oct2priv == NULL) {
 590         ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 591         return 0;
 592     }
 593     return eckey->group->meth->oct2priv(eckey, buf, len);
 594 }
 595
 596 int ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
 597 {
 598     if (eckey->priv_key == NULL)
 599         eckey->priv_key = BN_secure_new();
 600     if (eckey->priv_key == NULL) {
 601         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_MALLOC_FAILURE);
 602         return 0;
 603     }
 604     eckey->priv_key = BN_bin2bn(buf, len, eckey->priv_key);
 605     if (eckey->priv_key == NULL) {
 606         ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_BN_LIB);
 607         return 0;
 608     }
 609     return 1;
 610 }
 611
 612 size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf)
 613 {
 614     size_t len;
 615     unsigned char *buf;
 616     len = EC_KEY_priv2oct(eckey, NULL, 0);
 617     if (len == 0)
 618         return 0;
 619     buf = OPENSSL_malloc(len);
 620     if (buf == NULL)
 621         return 0;
 622     len = EC_KEY_priv2oct(eckey, buf, len);
 623     if (len == 0) {
 624         OPENSSL_free(buf);
 625         return 0;
 626     }
 627     *pbuf = buf;
 628     return len;
 629 }
 630
 631 int EC_KEY_can_sign(const EC_KEY *eckey)
 632 {
 633     if (eckey->group == NULL || eckey->group->meth == NULL
 634         || (eckey->group->meth->flags & EC_FLAGS_NO_SIGN))
 635         return 0;
 636     return 1;
 637 }