crypto/ec/ec_lib.c

   1 /*
   2  * Copyright 2001-2021 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  * EC_GROUP low level APIs are deprecated for public use, but still ok for
  13  * internal use.
  14  */
  15 #include "internal/deprecated.h"
  16
  17 #include <string.h>
  18 #include <openssl/params.h>
  19 #include <openssl/core_names.h>
  20 #include <openssl/err.h>
  21 #include <openssl/opensslv.h>
  22 #include "crypto/ec.h"
  23 #include "internal/nelem.h"
  24 #include "ec_local.h"
  25
  26 /* functions for EC_GROUP objects */
  27
  28 EC_GROUP *ossl_ec_group_new_ex(OSSL_LIB_CTX *libctx, const char *propq,
  29                                const EC_METHOD *meth)
  30 {
  31     EC_GROUP *ret;
  32
  33     if (meth == NULL) {
  34         ERR_raise(ERR_LIB_EC, EC_R_SLOT_FULL);
  35         return NULL;
  36     }
  37     if (meth->group_init == 0) {
  38         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
  39         return NULL;
  40     }
  41
  42     ret = OPENSSL_zalloc(sizeof(*ret));
  43     if (ret == NULL) {
  44         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
  45         return NULL;
  46     }
  47
  48     ret->libctx = libctx;
  49     if (propq != NULL) {
  50         ret->propq = OPENSSL_strdup(propq);
  51         if (ret->propq == NULL) {
  52             ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
  53             goto err;
  54         }
  55     }
  56     ret->meth = meth;
  57     if ((ret->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
  58         ret->order = BN_new();
  59         if (ret->order == NULL)
  60             goto err;
  61         ret->cofactor = BN_new();
  62         if (ret->cofactor == NULL)
  63             goto err;
  64     }
  65     ret->asn1_flag = OPENSSL_EC_EXPLICIT_CURVE;
  66     ret->asn1_form = POINT_CONVERSION_UNCOMPRESSED;
  67     if (!meth->group_init(ret))
  68         goto err;
  69     return ret;
  70
  71  err:
  72     BN_free(ret->order);
  73     BN_free(ret->cofactor);
  74     OPENSSL_free(ret->propq);
  75     OPENSSL_free(ret);
  76     return NULL;
  77 }
  78
  79 #ifndef OPENSSL_NO_DEPRECATED_3_0
  80 # ifndef FIPS_MODULE
  81 EC_GROUP *EC_GROUP_new(const EC_METHOD *meth)
  82 {
  83     return ossl_ec_group_new_ex(NULL, NULL, meth);
  84 }
  85 # endif
  86 #endif
  87
  88 void EC_pre_comp_free(EC_GROUP *group)
  89 {
  90     switch (group->pre_comp_type) {
  91     case PCT_none:
  92         break;
  93     case PCT_nistz256:
  94 #ifdef ECP_NISTZ256_ASM
  95         EC_nistz256_pre_comp_free(group->pre_comp.nistz256);
  96 #endif
  97         break;
  98 #ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
  99     case PCT_nistp224:
 100         EC_nistp224_pre_comp_free(group->pre_comp.nistp224);
 101         break;
 102     case PCT_nistp256:
 103         EC_nistp256_pre_comp_free(group->pre_comp.nistp256);
 104         break;
 105     case PCT_nistp521:
 106         EC_nistp521_pre_comp_free(group->pre_comp.nistp521);
 107         break;
 108 #else
 109     case PCT_nistp224:
 110     case PCT_nistp256:
 111     case PCT_nistp521:
 112         break;
 113 #endif
 114     case PCT_ec:
 115         EC_ec_pre_comp_free(group->pre_comp.ec);
 116         break;
 117     }
 118     group->pre_comp.ec = NULL;
 119 }
 120
 121 void EC_GROUP_free(EC_GROUP *group)
 122 {
 123     if (!group)
 124         return;
 125
 126     if (group->meth->group_finish != 0)
 127         group->meth->group_finish(group);
 128
 129     EC_pre_comp_free(group);
 130     BN_MONT_CTX_free(group->mont_data);
 131     EC_POINT_free(group->generator);
 132     BN_free(group->order);
 133     BN_free(group->cofactor);
 134     OPENSSL_free(group->seed);
 135     OPENSSL_free(group->propq);
 136     OPENSSL_free(group);
 137 }
 138
 139 #ifndef OPENSSL_NO_DEPRECATED_3_0
 140 void EC_GROUP_clear_free(EC_GROUP *group)
 141 {
 142     if (!group)
 143         return;
 144
 145     if (group->meth->group_clear_finish != 0)
 146         group->meth->group_clear_finish(group);
 147     else if (group->meth->group_finish != 0)
 148         group->meth->group_finish(group);
 149
 150     EC_pre_comp_free(group);
 151     BN_MONT_CTX_free(group->mont_data);
 152     EC_POINT_clear_free(group->generator);
 153     BN_clear_free(group->order);
 154     BN_clear_free(group->cofactor);
 155     OPENSSL_clear_free(group->seed, group->seed_len);
 156     OPENSSL_clear_free(group, sizeof(*group));
 157 }
 158 #endif
 159
 160 int EC_GROUP_copy(EC_GROUP *dest, const EC_GROUP *src)
 161 {
 162     if (dest->meth->group_copy == 0) {
 163         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 164         return 0;
 165     }
 166     if (dest->meth != src->meth) {
 167         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 168         return 0;
 169     }
 170     if (dest == src)
 171         return 1;
 172
 173     dest->libctx = src->libctx;
 174     dest->curve_name = src->curve_name;
 175
 176     /* Copy precomputed */
 177     dest->pre_comp_type = src->pre_comp_type;
 178     switch (src->pre_comp_type) {
 179     case PCT_none:
 180         dest->pre_comp.ec = NULL;
 181         break;
 182     case PCT_nistz256:
 183 #ifdef ECP_NISTZ256_ASM
 184         dest->pre_comp.nistz256 = EC_nistz256_pre_comp_dup(src->pre_comp.nistz256);
 185 #endif
 186         break;
 187 #ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
 188     case PCT_nistp224:
 189         dest->pre_comp.nistp224 = EC_nistp224_pre_comp_dup(src->pre_comp.nistp224);
 190         break;
 191     case PCT_nistp256:
 192         dest->pre_comp.nistp256 = EC_nistp256_pre_comp_dup(src->pre_comp.nistp256);
 193         break;
 194     case PCT_nistp521:
 195         dest->pre_comp.nistp521 = EC_nistp521_pre_comp_dup(src->pre_comp.nistp521);
 196         break;
 197 #else
 198     case PCT_nistp224:
 199     case PCT_nistp256:
 200     case PCT_nistp521:
 201         break;
 202 #endif
 203     case PCT_ec:
 204         dest->pre_comp.ec = EC_ec_pre_comp_dup(src->pre_comp.ec);
 205         break;
 206     }
 207
 208     if (src->mont_data != NULL) {
 209         if (dest->mont_data == NULL) {
 210             dest->mont_data = BN_MONT_CTX_new();
 211             if (dest->mont_data == NULL)
 212                 return 0;
 213         }
 214         if (!BN_MONT_CTX_copy(dest->mont_data, src->mont_data))
 215             return 0;
 216     } else {
 217         /* src->generator == NULL */
 218         BN_MONT_CTX_free(dest->mont_data);
 219         dest->mont_data = NULL;
 220     }
 221
 222     if (src->generator != NULL) {
 223         if (dest->generator == NULL) {
 224             dest->generator = EC_POINT_new(dest);
 225             if (dest->generator == NULL)
 226                 return 0;
 227         }
 228         if (!EC_POINT_copy(dest->generator, src->generator))
 229             return 0;
 230     } else {
 231         /* src->generator == NULL */
 232         EC_POINT_clear_free(dest->generator);
 233         dest->generator = NULL;
 234     }
 235
 236     if ((src->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
 237         if (!BN_copy(dest->order, src->order))
 238             return 0;
 239         if (!BN_copy(dest->cofactor, src->cofactor))
 240             return 0;
 241     }
 242
 243     dest->asn1_flag = src->asn1_flag;
 244     dest->asn1_form = src->asn1_form;
 245     dest->decoded_from_explicit_params = src->decoded_from_explicit_params;
 246
 247     if (src->seed) {
 248         OPENSSL_free(dest->seed);
 249         if ((dest->seed = OPENSSL_malloc(src->seed_len)) == NULL) {
 250             ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
 251             return 0;
 252         }
 253         if (!memcpy(dest->seed, src->seed, src->seed_len))
 254             return 0;
 255         dest->seed_len = src->seed_len;
 256     } else {
 257         OPENSSL_free(dest->seed);
 258         dest->seed = NULL;
 259         dest->seed_len = 0;
 260     }
 261
 262     return dest->meth->group_copy(dest, src);
 263 }
 264
 265 EC_GROUP *EC_GROUP_dup(const EC_GROUP *a)
 266 {
 267     EC_GROUP *t = NULL;
 268     int ok = 0;
 269
 270     if (a == NULL)
 271         return NULL;
 272
 273     if ((t = ossl_ec_group_new_ex(a->libctx, a->propq, a->meth)) == NULL)
 274         return NULL;
 275     if (!EC_GROUP_copy(t, a))
 276         goto err;
 277
 278     ok = 1;
 279
 280  err:
 281     if (!ok) {
 282         EC_GROUP_free(t);
 283         return NULL;
 284     }
 285         return t;
 286 }
 287
 288 #ifndef OPENSSL_NO_DEPRECATED_3_0
 289 const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group)
 290 {
 291     return group->meth;
 292 }
 293
 294 int EC_METHOD_get_field_type(const EC_METHOD *meth)
 295 {
 296     return meth->field_type;
 297 }
 298 #endif
 299
 300 static int ec_precompute_mont_data(EC_GROUP *);
 301
 302 /*-
 303  * Try computing cofactor from the generator order (n) and field cardinality (q).
 304  * This works for all curves of cryptographic interest.
 305  *
 306  * Hasse thm: q + 1 - 2*sqrt(q) <= n*h <= q + 1 + 2*sqrt(q)
 307  * h_min = (q + 1 - 2*sqrt(q))/n
 308  * h_max = (q + 1 + 2*sqrt(q))/n
 309  * h_max - h_min = 4*sqrt(q)/n
 310  * So if n > 4*sqrt(q) holds, there is only one possible value for h:
 311  * h = \lfloor (h_min + h_max)/2 \rceil = \lfloor (q + 1)/n \rceil
 312  *
 313  * Otherwise, zero cofactor and return success.
 314  */
 315 static int ec_guess_cofactor(EC_GROUP *group) {
 316     int ret = 0;
 317     BN_CTX *ctx = NULL;
 318     BIGNUM *q = NULL;
 319
 320     /*-
 321      * If the cofactor is too large, we cannot guess it.
 322      * The RHS of below is a strict overestimate of lg(4 * sqrt(q))
 323      */
 324     if (BN_num_bits(group->order) <= (BN_num_bits(group->field) + 1) / 2 + 3) {
 325         /* default to 0 */
 326         BN_zero(group->cofactor);
 327         /* return success */
 328         return 1;
 329     }
 330
 331     if ((ctx = BN_CTX_new_ex(group->libctx)) == NULL)
 332         return 0;
 333
 334     BN_CTX_start(ctx);
 335     if ((q = BN_CTX_get(ctx)) == NULL)
 336         goto err;
 337
 338     /* set q = 2**m for binary fields; q = p otherwise */
 339     if (group->meth->field_type == NID_X9_62_characteristic_two_field) {
 340         BN_zero(q);
 341         if (!BN_set_bit(q, BN_num_bits(group->field) - 1))
 342             goto err;
 343     } else {
 344         if (!BN_copy(q, group->field))
 345             goto err;
 346     }
 347
 348     /* compute h = \lfloor (q + 1)/n \rceil = \lfloor (q + 1 + n/2)/n \rfloor */
 349     if (!BN_rshift1(group->cofactor, group->order) /* n/2 */
 350         || !BN_add(group->cofactor, group->cofactor, q) /* q + n/2 */
 351         /* q + 1 + n/2 */
 352         || !BN_add(group->cofactor, group->cofactor, BN_value_one())
 353         /* (q + 1 + n/2)/n */
 354         || !BN_div(group->cofactor, NULL, group->cofactor, group->order, ctx))
 355         goto err;
 356     ret = 1;
 357  err:
 358     BN_CTX_end(ctx);
 359     BN_CTX_free(ctx);
 360     return ret;
 361 }
 362
 363 int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
 364                            const BIGNUM *order, const BIGNUM *cofactor)
 365 {
 366     if (generator == NULL) {
 367         ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
 368         return 0;
 369     }
 370
 371     /* require group->field >= 1 */
 372     if (group->field == NULL || BN_is_zero(group->field)
 373         || BN_is_negative(group->field)) {
 374         ERR_raise(ERR_LIB_EC, EC_R_INVALID_FIELD);
 375         return 0;
 376     }
 377
 378     /*-
 379      * - require order >= 1
 380      * - enforce upper bound due to Hasse thm: order can be no more than one bit
 381      *   longer than field cardinality
 382      */
 383     if (order == NULL || BN_is_zero(order) || BN_is_negative(order)
 384         || BN_num_bits(order) > BN_num_bits(group->field) + 1) {
 385         ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER);
 386         return 0;
 387     }
 388
 389     /*-
 390      * Unfortunately the cofactor is an optional field in many standards.
 391      * Internally, the lib uses 0 cofactor as a marker for "unknown cofactor".
 392      * So accept cofactor == NULL or cofactor >= 0.
 393      */
 394     if (cofactor != NULL && BN_is_negative(cofactor)) {
 395         ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_COFACTOR);
 396         return 0;
 397     }
 398
 399     if (group->generator == NULL) {
 400         group->generator = EC_POINT_new(group);
 401         if (group->generator == NULL)
 402             return 0;
 403     }
 404     if (!EC_POINT_copy(group->generator, generator))
 405         return 0;
 406
 407     if (!BN_copy(group->order, order))
 408         return 0;
 409
 410     /* Either take the provided positive cofactor, or try to compute it */
 411     if (cofactor != NULL && !BN_is_zero(cofactor)) {
 412         if (!BN_copy(group->cofactor, cofactor))
 413             return 0;
 414     } else if (!ec_guess_cofactor(group)) {
 415         BN_zero(group->cofactor);
 416         return 0;
 417     }
 418
 419     /*
 420      * Some groups have an order with
 421      * factors of two, which makes the Montgomery setup fail.
 422      * |group->mont_data| will be NULL in this case.
 423      */
 424     if (BN_is_odd(group->order)) {
 425         return ec_precompute_mont_data(group);
 426     }
 427
 428     BN_MONT_CTX_free(group->mont_data);
 429     group->mont_data = NULL;
 430     return 1;
 431 }
 432
 433 const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group)
 434 {
 435     return group->generator;
 436 }
 437
 438 BN_MONT_CTX *EC_GROUP_get_mont_data(const EC_GROUP *group)
 439 {
 440     return group->mont_data;
 441 }
 442
 443 int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx)
 444 {
 445     if (group->order == NULL)
 446         return 0;
 447     if (!BN_copy(order, group->order))
 448         return 0;
 449
 450     return !BN_is_zero(order);
 451 }
 452
 453 const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group)
 454 {
 455     return group->order;
 456 }
 457
 458 int EC_GROUP_order_bits(const EC_GROUP *group)
 459 {
 460     return group->meth->group_order_bits(group);
 461 }
 462
 463 int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor,
 464                           BN_CTX *ctx)
 465 {
 466
 467     if (group->cofactor == NULL)
 468         return 0;
 469     if (!BN_copy(cofactor, group->cofactor))
 470         return 0;
 471
 472     return !BN_is_zero(group->cofactor);
 473 }
 474
 475 const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group)
 476 {
 477     return group->cofactor;
 478 }
 479
 480 void EC_GROUP_set_curve_name(EC_GROUP *group, int nid)
 481 {
 482     group->curve_name = nid;
 483     group->asn1_flag =
 484         (nid != NID_undef)
 485         ? OPENSSL_EC_NAMED_CURVE
 486         : OPENSSL_EC_EXPLICIT_CURVE;
 487 }
 488
 489 int EC_GROUP_get_curve_name(const EC_GROUP *group)
 490 {
 491     return group->curve_name;
 492 }
 493
 494 const BIGNUM *EC_GROUP_get0_field(const EC_GROUP *group)
 495 {
 496     return group->field;
 497 }
 498
 499 int EC_GROUP_get_field_type(const EC_GROUP *group)
 500 {
 501     return group->meth->field_type;
 502 }
 503
 504 void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag)
 505 {
 506     group->asn1_flag = flag;
 507 }
 508
 509 int EC_GROUP_get_asn1_flag(const EC_GROUP *group)
 510 {
 511     return group->asn1_flag;
 512 }
 513
 514 void EC_GROUP_set_point_conversion_form(EC_GROUP *group,
 515                                         point_conversion_form_t form)
 516 {
 517     group->asn1_form = form;
 518 }
 519
 520 point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP
 521                                                            *group)
 522 {
 523     return group->asn1_form;
 524 }
 525
 526 size_t EC_GROUP_set_seed(EC_GROUP *group, const unsigned char *p, size_t len)
 527 {
 528     OPENSSL_free(group->seed);
 529     group->seed = NULL;
 530     group->seed_len = 0;
 531
 532     if (!len || !p)
 533         return 1;
 534
 535     if ((group->seed = OPENSSL_malloc(len)) == NULL) {
 536         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
 537         return 0;
 538     }
 539     memcpy(group->seed, p, len);
 540     group->seed_len = len;
 541
 542     return len;
 543 }
 544
 545 unsigned char *EC_GROUP_get0_seed(const EC_GROUP *group)
 546 {
 547     return group->seed;
 548 }
 549
 550 size_t EC_GROUP_get_seed_len(const EC_GROUP *group)
 551 {
 552     return group->seed_len;
 553 }
 554
 555 int EC_GROUP_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
 556                        const BIGNUM *b, BN_CTX *ctx)
 557 {
 558     if (group->meth->group_set_curve == 0) {
 559         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 560         return 0;
 561     }
 562     return group->meth->group_set_curve(group, p, a, b, ctx);
 563 }
 564
 565 int EC_GROUP_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b,
 566                        BN_CTX *ctx)
 567 {
 568     if (group->meth->group_get_curve == NULL) {
 569         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 570         return 0;
 571     }
 572     return group->meth->group_get_curve(group, p, a, b, ctx);
 573 }
 574
 575 #ifndef OPENSSL_NO_DEPRECATED_3_0
 576 int EC_GROUP_set_curve_GFp(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
 577                            const BIGNUM *b, BN_CTX *ctx)
 578 {
 579     return EC_GROUP_set_curve(group, p, a, b, ctx);
 580 }
 581
 582 int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
 583                            BIGNUM *b, BN_CTX *ctx)
 584 {
 585     return EC_GROUP_get_curve(group, p, a, b, ctx);
 586 }
 587
 588 # ifndef OPENSSL_NO_EC2M
 589 int EC_GROUP_set_curve_GF2m(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
 590                             const BIGNUM *b, BN_CTX *ctx)
 591 {
 592     return EC_GROUP_set_curve(group, p, a, b, ctx);
 593 }
 594
 595 int EC_GROUP_get_curve_GF2m(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
 596                             BIGNUM *b, BN_CTX *ctx)
 597 {
 598     return EC_GROUP_get_curve(group, p, a, b, ctx);
 599 }
 600 # endif
 601 #endif
 602
 603 int EC_GROUP_get_degree(const EC_GROUP *group)
 604 {
 605     if (group->meth->group_get_degree == 0) {
 606         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 607         return 0;
 608     }
 609     return group->meth->group_get_degree(group);
 610 }
 611
 612 int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
 613 {
 614     if (group->meth->group_check_discriminant == 0) {
 615         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 616         return 0;
 617     }
 618     return group->meth->group_check_discriminant(group, ctx);
 619 }
 620
 621 int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
 622 {
 623     int r = 0;
 624     BIGNUM *a1, *a2, *a3, *b1, *b2, *b3;
 625 #ifndef FIPS_MODULE
 626     BN_CTX *ctx_new = NULL;
 627 #endif
 628
 629     /* compare the field types */
 630     if (EC_GROUP_get_field_type(a) != EC_GROUP_get_field_type(b))
 631         return 1;
 632     /* compare the curve name (if present in both) */
 633     if (EC_GROUP_get_curve_name(a) && EC_GROUP_get_curve_name(b) &&
 634         EC_GROUP_get_curve_name(a) != EC_GROUP_get_curve_name(b))
 635         return 1;
 636     if (a->meth->flags & EC_FLAGS_CUSTOM_CURVE)
 637         return 0;
 638
 639 #ifndef FIPS_MODULE
 640     if (ctx == NULL)
 641         ctx_new = ctx = BN_CTX_new();
 642 #endif
 643     if (ctx == NULL)
 644         return -1;
 645
 646     BN_CTX_start(ctx);
 647     a1 = BN_CTX_get(ctx);
 648     a2 = BN_CTX_get(ctx);
 649     a3 = BN_CTX_get(ctx);
 650     b1 = BN_CTX_get(ctx);
 651     b2 = BN_CTX_get(ctx);
 652     b3 = BN_CTX_get(ctx);
 653     if (b3 == NULL) {
 654         BN_CTX_end(ctx);
 655 #ifndef FIPS_MODULE
 656         BN_CTX_free(ctx_new);
 657 #endif
 658         return -1;
 659     }
 660
 661     /*
 662      * XXX This approach assumes that the external representation of curves
 663      * over the same field type is the same.
 664      */
 665     if (!a->meth->group_get_curve(a, a1, a2, a3, ctx) ||
 666         !b->meth->group_get_curve(b, b1, b2, b3, ctx))
 667         r = 1;
 668
 669     /* return 1 if the curve parameters are different */
 670     if (r || BN_cmp(a1, b1) != 0 || BN_cmp(a2, b2) != 0 || BN_cmp(a3, b3) != 0)
 671         r = 1;
 672
 673     /* XXX EC_POINT_cmp() assumes that the methods are equal */
 674     /* return 1 if the generators are different */
 675     if (r || EC_POINT_cmp(a, EC_GROUP_get0_generator(a),
 676                           EC_GROUP_get0_generator(b), ctx) != 0)
 677         r = 1;
 678
 679     if (!r) {
 680         const BIGNUM *ao, *bo, *ac, *bc;
 681         /* compare the orders */
 682         ao = EC_GROUP_get0_order(a);
 683         bo = EC_GROUP_get0_order(b);
 684         if (ao == NULL || bo == NULL) {
 685             /* return an error if either order is NULL */
 686             r = -1;
 687             goto end;
 688         }
 689         if (BN_cmp(ao, bo) != 0) {
 690             /* return 1 if orders are different */
 691             r = 1;
 692             goto end;
 693         }
 694         /*
 695          * It gets here if the curve parameters and generator matched.
 696          * Now check the optional cofactors (if both are present).
 697          */
 698         ac = EC_GROUP_get0_cofactor(a);
 699         bc = EC_GROUP_get0_cofactor(b);
 700         /* Returns 1 (mismatch) if both cofactors are specified and different */
 701         if (!BN_is_zero(ac) && !BN_is_zero(bc) && BN_cmp(ac, bc) != 0)
 702             r = 1;
 703         /* Returns 0 if the parameters matched */
 704     }
 705 end:
 706     BN_CTX_end(ctx);
 707 #ifndef FIPS_MODULE
 708     BN_CTX_free(ctx_new);
 709 #endif
 710     return r;
 711 }
 712
 713 /* functions for EC_POINT objects */
 714
 715 EC_POINT *EC_POINT_new(const EC_GROUP *group)
 716 {
 717     EC_POINT *ret;
 718
 719     if (group == NULL) {
 720         ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
 721         return NULL;
 722     }
 723     if (group->meth->point_init == NULL) {
 724         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 725         return NULL;
 726     }
 727
 728     ret = OPENSSL_zalloc(sizeof(*ret));
 729     if (ret == NULL) {
 730         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
 731         return NULL;
 732     }
 733
 734     ret->meth = group->meth;
 735     ret->curve_name = group->curve_name;
 736
 737     if (!ret->meth->point_init(ret)) {
 738         OPENSSL_free(ret);
 739         return NULL;
 740     }
 741
 742     return ret;
 743 }
 744
 745 void EC_POINT_free(EC_POINT *point)
 746 {
 747     if (point == NULL)
 748         return;
 749
 750     if (point->meth->point_finish != 0)
 751         point->meth->point_finish(point);
 752     OPENSSL_free(point);
 753 }
 754
 755 void EC_POINT_clear_free(EC_POINT *point)
 756 {
 757     if (point == NULL)
 758         return;
 759
 760     if (point->meth->point_clear_finish != 0)
 761         point->meth->point_clear_finish(point);
 762     else if (point->meth->point_finish != 0)
 763         point->meth->point_finish(point);
 764     OPENSSL_clear_free(point, sizeof(*point));
 765 }
 766
 767 int EC_POINT_copy(EC_POINT *dest, const EC_POINT *src)
 768 {
 769     if (dest->meth->point_copy == 0) {
 770         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 771         return 0;
 772     }
 773     if (dest->meth != src->meth
 774             || (dest->curve_name != src->curve_name
 775                  && dest->curve_name != 0
 776                  && src->curve_name != 0)) {
 777         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 778         return 0;
 779     }
 780     if (dest == src)
 781         return 1;
 782     return dest->meth->point_copy(dest, src);
 783 }
 784
 785 EC_POINT *EC_POINT_dup(const EC_POINT *a, const EC_GROUP *group)
 786 {
 787     EC_POINT *t;
 788     int r;
 789
 790     if (a == NULL)
 791         return NULL;
 792
 793     t = EC_POINT_new(group);
 794     if (t == NULL)
 795         return NULL;
 796     r = EC_POINT_copy(t, a);
 797     if (!r) {
 798         EC_POINT_free(t);
 799         return NULL;
 800     }
 801     return t;
 802 }
 803
 804 #ifndef OPENSSL_NO_DEPRECATED_3_0
 805 const EC_METHOD *EC_POINT_method_of(const EC_POINT *point)
 806 {
 807     return point->meth;
 808 }
 809 #endif
 810
 811 int EC_POINT_set_to_infinity(const EC_GROUP *group, EC_POINT *point)
 812 {
 813     if (group->meth->point_set_to_infinity == 0) {
 814         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 815         return 0;
 816     }
 817     if (group->meth != point->meth) {
 818         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 819         return 0;
 820     }
 821     return group->meth->point_set_to_infinity(group, point);
 822 }
 823
 824 #ifndef OPENSSL_NO_DEPRECATED_3_0
 825 int EC_POINT_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
 826                                              EC_POINT *point, const BIGNUM *x,
 827                                              const BIGNUM *y, const BIGNUM *z,
 828                                              BN_CTX *ctx)
 829 {
 830     if (group->meth->field_type != NID_X9_62_prime_field) {
 831         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 832         return 0;
 833     }
 834     if (!ec_point_is_compat(point, group)) {
 835         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 836         return 0;
 837     }
 838     return ossl_ec_GFp_simple_set_Jprojective_coordinates_GFp(group, point,
 839                                                               x, y, z, ctx);
 840 }
 841
 842 int EC_POINT_get_Jprojective_coordinates_GFp(const EC_GROUP *group,
 843                                              const EC_POINT *point, BIGNUM *x,
 844                                              BIGNUM *y, BIGNUM *z,
 845                                              BN_CTX *ctx)
 846 {
 847     if (group->meth->field_type != NID_X9_62_prime_field) {
 848         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 849         return 0;
 850     }
 851     if (!ec_point_is_compat(point, group)) {
 852         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 853         return 0;
 854     }
 855     return ossl_ec_GFp_simple_get_Jprojective_coordinates_GFp(group, point,
 856                                                               x, y, z, ctx);
 857 }
 858 #endif
 859
 860 int EC_POINT_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point,
 861                                     const BIGNUM *x, const BIGNUM *y,
 862                                     BN_CTX *ctx)
 863 {
 864     if (group->meth->point_set_affine_coordinates == NULL) {
 865         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 866         return 0;
 867     }
 868     if (!ec_point_is_compat(point, group)) {
 869         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 870         return 0;
 871     }
 872     if (!group->meth->point_set_affine_coordinates(group, point, x, y, ctx))
 873         return 0;
 874
 875     if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
 876         ERR_raise(ERR_LIB_EC, EC_R_POINT_IS_NOT_ON_CURVE);
 877         return 0;
 878     }
 879     return 1;
 880 }
 881
 882 #ifndef OPENSSL_NO_DEPRECATED_3_0
 883 int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group,
 884                                         EC_POINT *point, const BIGNUM *x,
 885                                         const BIGNUM *y, BN_CTX *ctx)
 886 {
 887     return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
 888 }
 889
 890 # ifndef OPENSSL_NO_EC2M
 891 int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group,
 892                                          EC_POINT *point, const BIGNUM *x,
 893                                          const BIGNUM *y, BN_CTX *ctx)
 894 {
 895     return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
 896 }
 897 # endif
 898 #endif
 899
 900 int EC_POINT_get_affine_coordinates(const EC_GROUP *group,
 901                                     const EC_POINT *point, BIGNUM *x, BIGNUM *y,
 902                                     BN_CTX *ctx)
 903 {
 904     if (group->meth->point_get_affine_coordinates == NULL) {
 905         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 906         return 0;
 907     }
 908     if (!ec_point_is_compat(point, group)) {
 909         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 910         return 0;
 911     }
 912     if (EC_POINT_is_at_infinity(group, point)) {
 913         ERR_raise(ERR_LIB_EC, EC_R_POINT_AT_INFINITY);
 914         return 0;
 915     }
 916     return group->meth->point_get_affine_coordinates(group, point, x, y, ctx);
 917 }
 918
 919 #ifndef OPENSSL_NO_DEPRECATED_3_0
 920 int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
 921                                         const EC_POINT *point, BIGNUM *x,
 922                                         BIGNUM *y, BN_CTX *ctx)
 923 {
 924     return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
 925 }
 926
 927 # ifndef OPENSSL_NO_EC2M
 928 int EC_POINT_get_affine_coordinates_GF2m(const EC_GROUP *group,
 929                                          const EC_POINT *point, BIGNUM *x,
 930                                          BIGNUM *y, BN_CTX *ctx)
 931 {
 932     return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
 933 }
 934 # endif
 935 #endif
 936
 937 int EC_POINT_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
 938                  const EC_POINT *b, BN_CTX *ctx)
 939 {
 940     if (group->meth->add == 0) {
 941         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 942         return 0;
 943     }
 944     if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)
 945         || !ec_point_is_compat(b, group)) {
 946         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 947         return 0;
 948     }
 949     return group->meth->add(group, r, a, b, ctx);
 950 }
 951
 952 int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
 953                  BN_CTX *ctx)
 954 {
 955     if (group->meth->dbl == 0) {
 956         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 957         return 0;
 958     }
 959     if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)) {
 960         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 961         return 0;
 962     }
 963     return group->meth->dbl(group, r, a, ctx);
 964 }
 965
 966 int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a, BN_CTX *ctx)
 967 {
 968     if (group->meth->invert == 0) {
 969         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 970         return 0;
 971     }
 972     if (!ec_point_is_compat(a, group)) {
 973         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 974         return 0;
 975     }
 976     return group->meth->invert(group, a, ctx);
 977 }
 978
 979 int EC_POINT_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
 980 {
 981     if (group->meth->is_at_infinity == 0) {
 982         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
 983         return 0;
 984     }
 985     if (!ec_point_is_compat(point, group)) {
 986         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
 987         return 0;
 988     }
 989     return group->meth->is_at_infinity(group, point);
 990 }
 991
 992 /*
 993  * Check whether an EC_POINT is on the curve or not. Note that the return
 994  * value for this function should NOT be treated as a boolean. Return values:
 995  *  1: The point is on the curve
 996  *  0: The point is not on the curve
 997  * -1: An error occurred
 998  */
 999 int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point,
1000                          BN_CTX *ctx)
1001 {
1002     if (group->meth->is_on_curve == 0) {
1003         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1004         return 0;
1005     }
1006     if (!ec_point_is_compat(point, group)) {
1007         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1008         return 0;
1009     }
1010     return group->meth->is_on_curve(group, point, ctx);
1011 }
1012
1013 int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b,
1014                  BN_CTX *ctx)
1015 {
1016     if (group->meth->point_cmp == 0) {
1017         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1018         return -1;
1019     }
1020     if (!ec_point_is_compat(a, group) || !ec_point_is_compat(b, group)) {
1021         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1022         return -1;
1023     }
1024     return group->meth->point_cmp(group, a, b, ctx);
1025 }
1026
1027 #ifndef OPENSSL_NO_DEPRECATED_3_0
1028 int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
1029 {
1030     if (group->meth->make_affine == 0) {
1031         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1032         return 0;
1033     }
1034     if (!ec_point_is_compat(point, group)) {
1035         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1036         return 0;
1037     }
1038     return group->meth->make_affine(group, point, ctx);
1039 }
1040
1041 int EC_POINTs_make_affine(const EC_GROUP *group, size_t num,
1042                           EC_POINT *points[], BN_CTX *ctx)
1043 {
1044     size_t i;
1045
1046     if (group->meth->points_make_affine == 0) {
1047         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1048         return 0;
1049     }
1050     for (i = 0; i < num; i++) {
1051         if (!ec_point_is_compat(points[i], group)) {
1052             ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1053             return 0;
1054         }
1055     }
1056     return group->meth->points_make_affine(group, num, points, ctx);
1057 }
1058 #endif
1059
1060 /*
1061  * Functions for point multiplication. If group->meth->mul is 0, we use the
1062  * wNAF-based implementations in ec_mult.c; otherwise we dispatch through
1063  * methods.
1064  */
1065
1066 #ifndef OPENSSL_NO_DEPRECATED_3_0
1067 int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
1068                   size_t num, const EC_POINT *points[],
1069                   const BIGNUM *scalars[], BN_CTX *ctx)
1070 {
1071     int ret = 0;
1072     size_t i = 0;
1073 #ifndef FIPS_MODULE
1074     BN_CTX *new_ctx = NULL;
1075 #endif
1076
1077     if (!ec_point_is_compat(r, group)) {
1078         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1079         return 0;
1080     }
1081
1082     if (scalar == NULL && num == 0)
1083         return EC_POINT_set_to_infinity(group, r);
1084
1085     for (i = 0; i < num; i++) {
1086         if (!ec_point_is_compat(points[i], group)) {
1087             ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1088             return 0;
1089         }
1090     }
1091
1092 #ifndef FIPS_MODULE
1093     if (ctx == NULL)
1094         ctx = new_ctx = BN_CTX_secure_new();
1095 #endif
1096     if (ctx == NULL) {
1097         ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
1098         return 0;
1099     }
1100
1101     if (group->meth->mul != NULL)
1102         ret = group->meth->mul(group, r, scalar, num, points, scalars, ctx);
1103     else
1104         /* use default */
1105         ret = ossl_ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
1106
1107 #ifndef FIPS_MODULE
1108     BN_CTX_free(new_ctx);
1109 #endif
1110     return ret;
1111 }
1112 #endif
1113
1114 int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
1115                  const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx)
1116 {
1117     int ret = 0;
1118     size_t num;
1119 #ifndef FIPS_MODULE
1120     BN_CTX *new_ctx = NULL;
1121 #endif
1122
1123     if (!ec_point_is_compat(r, group)
1124         || (point != NULL && !ec_point_is_compat(point, group))) {
1125         ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1126         return 0;
1127     }
1128
1129     if (g_scalar == NULL && p_scalar == NULL)
1130         return EC_POINT_set_to_infinity(group, r);
1131
1132 #ifndef FIPS_MODULE
1133     if (ctx == NULL)
1134         ctx = new_ctx = BN_CTX_secure_new();
1135 #endif
1136     if (ctx == NULL) {
1137         ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
1138         return 0;
1139     }
1140
1141     num = (point != NULL && p_scalar != NULL) ? 1 : 0;
1142     if (group->meth->mul != NULL)
1143         ret = group->meth->mul(group, r, g_scalar, num, &point, &p_scalar, ctx);
1144     else
1145         /* use default */
1146         ret = ossl_ec_wNAF_mul(group, r, g_scalar, num, &point, &p_scalar, ctx);
1147
1148 #ifndef FIPS_MODULE
1149     BN_CTX_free(new_ctx);
1150 #endif
1151     return ret;
1152 }
1153
1154 #ifndef OPENSSL_NO_DEPRECATED_3_0
1155 int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
1156 {
1157     if (group->meth->mul == 0)
1158         /* use default */
1159         return ossl_ec_wNAF_precompute_mult(group, ctx);
1160
1161     if (group->meth->precompute_mult != 0)
1162         return group->meth->precompute_mult(group, ctx);
1163     else
1164         return 1;               /* nothing to do, so report success */
1165 }
1166
1167 int EC_GROUP_have_precompute_mult(const EC_GROUP *group)
1168 {
1169     if (group->meth->mul == 0)
1170         /* use default */
1171         return ossl_ec_wNAF_have_precompute_mult(group);
1172
1173     if (group->meth->have_precompute_mult != 0)
1174         return group->meth->have_precompute_mult(group);
1175     else
1176         return 0;               /* cannot tell whether precomputation has
1177                                  * been performed */
1178 }
1179 #endif
1180
1181 /*
1182  * ec_precompute_mont_data sets |group->mont_data| from |group->order| and
1183  * returns one on success. On error it returns zero.
1184  */
1185 static int ec_precompute_mont_data(EC_GROUP *group)
1186 {
1187     BN_CTX *ctx = BN_CTX_new_ex(group->libctx);
1188     int ret = 0;
1189
1190     BN_MONT_CTX_free(group->mont_data);
1191     group->mont_data = NULL;
1192
1193     if (ctx == NULL)
1194         goto err;
1195
1196     group->mont_data = BN_MONT_CTX_new();
1197     if (group->mont_data == NULL)
1198         goto err;
1199
1200     if (!BN_MONT_CTX_set(group->mont_data, group->order, ctx)) {
1201         BN_MONT_CTX_free(group->mont_data);
1202         group->mont_data = NULL;
1203         goto err;
1204     }
1205
1206     ret = 1;
1207
1208  err:
1209
1210     BN_CTX_free(ctx);
1211     return ret;
1212 }
1213
1214 #ifndef FIPS_MODULE
1215 int EC_KEY_set_ex_data(EC_KEY *key, int idx, void *arg)
1216 {
1217     return CRYPTO_set_ex_data(&key->ex_data, idx, arg);
1218 }
1219
1220 void *EC_KEY_get_ex_data(const EC_KEY *key, int idx)
1221 {
1222     return CRYPTO_get_ex_data(&key->ex_data, idx);
1223 }
1224 #endif
1225
1226 int ossl_ec_group_simple_order_bits(const EC_GROUP *group)
1227 {
1228     if (group->order == NULL)
1229         return 0;
1230     return BN_num_bits(group->order);
1231 }
1232
1233 static int ec_field_inverse_mod_ord(const EC_GROUP *group, BIGNUM *r,
1234                                     const BIGNUM *x, BN_CTX *ctx)
1235 {
1236     BIGNUM *e = NULL;
1237     int ret = 0;
1238 #ifndef FIPS_MODULE
1239     BN_CTX *new_ctx = NULL;
1240 #endif
1241
1242     if (group->mont_data == NULL)
1243         return 0;
1244
1245 #ifndef FIPS_MODULE
1246     if (ctx == NULL)
1247         ctx = new_ctx = BN_CTX_secure_new();
1248 #endif
1249     if (ctx == NULL)
1250         return 0;
1251
1252     BN_CTX_start(ctx);
1253     if ((e = BN_CTX_get(ctx)) == NULL)
1254         goto err;
1255
1256     /*-
1257      * We want inverse in constant time, therefore we utilize the fact
1258      * order must be prime and use Fermats Little Theorem instead.
1259      */
1260     if (!BN_set_word(e, 2))
1261         goto err;
1262     if (!BN_sub(e, group->order, e))
1263         goto err;
1264     /*-
1265      * Exponent e is public.
1266      * No need for scatter-gather or BN_FLG_CONSTTIME.
1267      */
1268     if (!BN_mod_exp_mont(r, x, e, group->order, ctx, group->mont_data))
1269         goto err;
1270
1271     ret = 1;
1272
1273  err:
1274     BN_CTX_end(ctx);
1275 #ifndef FIPS_MODULE
1276     BN_CTX_free(new_ctx);
1277 #endif
1278     return ret;
1279 }
1280
1281 /*-
1282  * Default behavior, if group->meth->field_inverse_mod_ord is NULL:
1283  * - When group->order is even, this function returns an error.
1284  * - When group->order is otherwise composite, the correctness
1285  *   of the output is not guaranteed.
1286  * - When x is outside the range [1, group->order), the correctness
1287  *   of the output is not guaranteed.
1288  * - Otherwise, this function returns the multiplicative inverse in the
1289  *   range [1, group->order).
1290  *
1291  * EC_METHODs must implement their own field_inverse_mod_ord for
1292  * other functionality.
1293  */
1294 int ossl_ec_group_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
1295                                  const BIGNUM *x, BN_CTX *ctx)
1296 {
1297     if (group->meth->field_inverse_mod_ord != NULL)
1298         return group->meth->field_inverse_mod_ord(group, res, x, ctx);
1299     else
1300         return ec_field_inverse_mod_ord(group, res, x, ctx);
1301 }
1302
1303 /*-
1304  * Coordinate blinding for EC_POINT.
1305  *
1306  * The underlying EC_METHOD can optionally implement this function:
1307  * underlying implementations should return 0 on errors, or 1 on
1308  * success.
1309  *
1310  * This wrapper returns 1 in case the underlying EC_METHOD does not
1311  * support coordinate blinding.
1312  */
1313 int ossl_ec_point_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
1314                                     BN_CTX *ctx)
1315 {
1316     if (group->meth->blind_coordinates == NULL)
1317         return 1; /* ignore if not implemented */
1318
1319     return group->meth->blind_coordinates(group, p, ctx);
1320 }
1321
1322 int EC_GROUP_get_basis_type(const EC_GROUP *group)
1323 {
1324     int i;
1325
1326     if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field)
1327         /* everything else is currently not supported */
1328         return 0;
1329
1330     /* Find the last non-zero element of group->poly[] */
1331     for (i = 0;
1332          i < (int)OSSL_NELEM(group->poly) && group->poly[i] != 0;
1333          i++)
1334         continue;
1335
1336     if (i == 4)
1337         return NID_X9_62_ppBasis;
1338     else if (i == 2)
1339         return NID_X9_62_tpBasis;
1340     else
1341         /* everything else is currently not supported */
1342         return 0;
1343 }
1344
1345 #ifndef OPENSSL_NO_EC2M
1346 int EC_GROUP_get_trinomial_basis(const EC_GROUP *group, unsigned int *k)
1347 {
1348     if (group == NULL)
1349         return 0;
1350
1351     if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field
1352         || !((group->poly[0] != 0) && (group->poly[1] != 0)
1353              && (group->poly[2] == 0))) {
1354         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1355         return 0;
1356     }
1357
1358     if (k)
1359         *k = group->poly[1];
1360
1361     return 1;
1362 }
1363
1364 int EC_GROUP_get_pentanomial_basis(const EC_GROUP *group, unsigned int *k1,
1365                                    unsigned int *k2, unsigned int *k3)
1366 {
1367     if (group == NULL)
1368         return 0;
1369
1370     if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field
1371         || !((group->poly[0] != 0) && (group->poly[1] != 0)
1372              && (group->poly[2] != 0) && (group->poly[3] != 0)
1373              && (group->poly[4] == 0))) {
1374         ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1375         return 0;
1376     }
1377
1378     if (k1)
1379         *k1 = group->poly[3];
1380     if (k2)
1381         *k2 = group->poly[2];
1382     if (k3)
1383         *k3 = group->poly[1];
1384
1385     return 1;
1386 }
1387 #endif
1388
1389 #ifndef FIPS_MODULE
1390 /*
1391  * Check if the explicit parameters group matches any built-in curves.
1392  *
1393  * We create a copy of the group just built, so that we can remove optional
1394  * fields for the lookup: we do this to avoid the possibility that one of
1395  * the optional parameters is used to force the library into using a less
1396  * performant and less secure EC_METHOD instead of the specialized one.
1397  * In any case, `seed` is not really used in any computation, while a
1398  * cofactor different from the one in the built-in table is just
1399  * mathematically wrong anyway and should not be used.
1400  */
1401 static EC_GROUP *ec_group_explicit_to_named(const EC_GROUP *group,
1402                                             OSSL_LIB_CTX *libctx,
1403                                             const char *propq,
1404                                             BN_CTX *ctx)
1405 {
1406     EC_GROUP *ret_group = NULL, *dup = NULL;
1407     int curve_name_nid;
1408
1409     const EC_POINT *point = EC_GROUP_get0_generator(group);
1410     const BIGNUM *order = EC_GROUP_get0_order(group);
1411     int no_seed = (EC_GROUP_get0_seed(group) == NULL);
1412
1413     if ((dup = EC_GROUP_dup(group)) == NULL
1414             || EC_GROUP_set_seed(dup, NULL, 0) != 1
1415             || !EC_GROUP_set_generator(dup, point, order, NULL))
1416         goto err;
1417     if ((curve_name_nid = ossl_ec_curve_nid_from_params(dup, ctx)) != NID_undef) {
1418         /*
1419          * The input explicit parameters successfully matched one of the
1420          * built-in curves: often for built-in curves we have specialized
1421          * methods with better performance and hardening.
1422          *
1423          * In this case we replace the `EC_GROUP` created through explicit
1424          * parameters with one created from a named group.
1425          */
1426
1427 # ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
1428         /*
1429          * NID_wap_wsg_idm_ecid_wtls12 and NID_secp224r1 are both aliases for
1430          * the same curve, we prefer the SECP nid when matching explicit
1431          * parameters as that is associated with a specialized EC_METHOD.
1432          */
1433         if (curve_name_nid == NID_wap_wsg_idm_ecid_wtls12)
1434             curve_name_nid = NID_secp224r1;
1435 # endif /* !def(OPENSSL_NO_EC_NISTP_64_GCC_128) */
1436
1437         ret_group = EC_GROUP_new_by_curve_name_ex(libctx, propq, curve_name_nid);
1438         if (ret_group == NULL)
1439             goto err;
1440
1441         /*
1442          * Set the flag so that EC_GROUPs created from explicit parameters are
1443          * serialized using explicit parameters by default.
1444          */
1445         EC_GROUP_set_asn1_flag(ret_group, OPENSSL_EC_EXPLICIT_CURVE);
1446
1447         /*
1448          * If the input params do not contain the optional seed field we make
1449          * sure it is not added to the returned group.
1450          *
1451          * The seed field is not really used inside libcrypto anyway, and
1452          * adding it to parsed explicit parameter keys would alter their DER
1453          * encoding output (because of the extra field) which could impact
1454          * applications fingerprinting keys by their DER encoding.
1455          */
1456         if (no_seed) {
1457             if (EC_GROUP_set_seed(ret_group, NULL, 0) != 1)
1458                 goto err;
1459         }
1460     } else {
1461         ret_group = (EC_GROUP *)group;
1462     }
1463     EC_GROUP_free(dup);
1464     return ret_group;
1465 err:
1466     EC_GROUP_free(dup);
1467     EC_GROUP_free(ret_group);
1468     return NULL;
1469 }
1470 #endif /* FIPS_MODULE */
1471
1472 static EC_GROUP *group_new_from_name(const OSSL_PARAM *p,
1473                                      OSSL_LIB_CTX *libctx, const char *propq)
1474 {
1475     int ok = 0, nid;
1476     const char *curve_name = NULL;
1477
1478     switch (p->data_type) {
1479     case OSSL_PARAM_UTF8_STRING:
1480         /* The OSSL_PARAM functions have no support for this */
1481         curve_name = p->data;
1482         ok = (curve_name != NULL);
1483         break;
1484     case OSSL_PARAM_UTF8_PTR:
1485         ok = OSSL_PARAM_get_utf8_ptr(p, &curve_name);
1486         break;
1487     }
1488
1489     if (ok) {
1490         nid = ossl_ec_curve_name2nid(curve_name);
1491         if (nid == NID_undef) {
1492             ERR_raise(ERR_LIB_EC, EC_R_INVALID_CURVE);
1493             return NULL;
1494         } else {
1495             return EC_GROUP_new_by_curve_name_ex(libctx, propq, nid);
1496         }
1497     }
1498     return NULL;
1499 }
1500
1501 /* These parameters can be set directly into an EC_GROUP */
1502 int ossl_ec_group_set_params(EC_GROUP *group, const OSSL_PARAM params[])
1503 {
1504     int encoding_flag = -1, format = -1;
1505     const OSSL_PARAM *p;
1506
1507     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_POINT_CONVERSION_FORMAT);
1508     if (p != NULL) {
1509         if (!ossl_ec_pt_format_param2id(p, &format)) {
1510             ECerr(0, EC_R_INVALID_FORM);
1511             return 0;
1512         }
1513         EC_GROUP_set_point_conversion_form(group, format);
1514     }
1515
1516     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ENCODING);
1517     if (p != NULL) {
1518         if (!ossl_ec_encoding_param2id(p, &encoding_flag)) {
1519             ECerr(0, EC_R_INVALID_FORM);
1520             return 0;
1521         }
1522         EC_GROUP_set_asn1_flag(group, encoding_flag);
1523     }
1524     /* Optional seed */
1525     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_SEED);
1526     if (p != NULL) {
1527         /* The seed is allowed to be NULL */
1528         if (p->data_type != OSSL_PARAM_OCTET_STRING
1529             || !EC_GROUP_set_seed(group, p->data, p->data_size)) {
1530             ECerr(0, EC_R_INVALID_SEED);
1531             return 0;
1532         }
1533     }
1534     return 1;
1535 }
1536
1537 EC_GROUP *EC_GROUP_new_from_params(const OSSL_PARAM params[],
1538                                    OSSL_LIB_CTX *libctx, const char *propq)
1539 {
1540     const OSSL_PARAM *ptmp;
1541     EC_GROUP *group = NULL;
1542
1543 #ifndef FIPS_MODULE
1544     const OSSL_PARAM *pa, *pb;
1545     int ok = 0;
1546     EC_GROUP *named_group = NULL;
1547     BIGNUM *p = NULL, *a = NULL, *b = NULL, *order = NULL, *cofactor = NULL;
1548     EC_POINT *point = NULL;
1549     int field_bits = 0;
1550     int is_prime_field = 1;
1551     BN_CTX *bnctx = NULL;
1552     const unsigned char *buf = NULL;
1553     int encoding_flag = -1;
1554 #endif
1555
1556     /* This is the simple named group case */
1557     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_GROUP_NAME);
1558     if (ptmp != NULL) {
1559         group = group_new_from_name(ptmp, libctx, propq);
1560         if (group != NULL) {
1561             if (!ossl_ec_group_set_params(group, params)) {
1562                 EC_GROUP_free(group);
1563                 group = NULL;
1564             }
1565         }
1566         return group;
1567     }
1568 #ifdef FIPS_MODULE
1569     ERR_raise(ERR_LIB_EC, EC_R_EXPLICIT_PARAMS_NOT_SUPPORTED);
1570     return NULL;
1571 #else
1572     /* If it gets here then we are trying explicit parameters */
1573     bnctx = BN_CTX_new_ex(libctx);
1574     if (bnctx == NULL) {
1575         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
1576         return 0;
1577     }
1578     BN_CTX_start(bnctx);
1579
1580     p = BN_CTX_get(bnctx);
1581     a = BN_CTX_get(bnctx);
1582     b = BN_CTX_get(bnctx);
1583     order = BN_CTX_get(bnctx);
1584     if (order == NULL) {
1585         ERR_raise(ERR_LIB_EC, ERR_R_MALLOC_FAILURE);
1586         goto err;
1587     }
1588
1589     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_FIELD_TYPE);
1590     if (ptmp == NULL || ptmp->data_type != OSSL_PARAM_UTF8_STRING) {
1591         ERR_raise(ERR_LIB_EC, EC_R_INVALID_FIELD);
1592         goto err;
1593     }
1594     if (OPENSSL_strcasecmp(ptmp->data, SN_X9_62_prime_field) == 0) {
1595         is_prime_field = 1;
1596     } else if (OPENSSL_strcasecmp(ptmp->data,
1597                                   SN_X9_62_characteristic_two_field) == 0) {
1598         is_prime_field = 0;
1599     } else {
1600         /* Invalid field */
1601         ERR_raise(ERR_LIB_EC, EC_R_UNSUPPORTED_FIELD);
1602         goto err;
1603     }
1604
1605     pa = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_A);
1606     if (!OSSL_PARAM_get_BN(pa, &a)) {
1607         ERR_raise(ERR_LIB_EC, EC_R_INVALID_A);
1608         goto err;
1609     }
1610     pb = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_B);
1611     if (!OSSL_PARAM_get_BN(pb, &b)) {
1612         ERR_raise(ERR_LIB_EC, EC_R_INVALID_B);
1613         goto err;
1614     }
1615
1616     /* extract the prime number or irreducible polynomial */
1617     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_P);
1618     if (!OSSL_PARAM_get_BN(ptmp, &p)) {
1619         ERR_raise(ERR_LIB_EC, EC_R_INVALID_P);
1620         goto err;
1621     }
1622
1623     if (is_prime_field) {
1624         if (BN_is_negative(p) || BN_is_zero(p)) {
1625             ERR_raise(ERR_LIB_EC, EC_R_INVALID_P);
1626             goto err;
1627         }
1628         field_bits = BN_num_bits(p);
1629         if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS) {
1630             ERR_raise(ERR_LIB_EC, EC_R_FIELD_TOO_LARGE);
1631             goto err;
1632         }
1633
1634         /* create the EC_GROUP structure */
1635         group = EC_GROUP_new_curve_GFp(p, a, b, bnctx);
1636     } else {
1637 # ifdef OPENSSL_NO_EC2M
1638         ERR_raise(ERR_LIB_EC, EC_R_GF2M_NOT_SUPPORTED);
1639         goto err;
1640 # else
1641         /* create the EC_GROUP structure */
1642         group = EC_GROUP_new_curve_GF2m(p, a, b, NULL);
1643         if (group != NULL) {
1644             field_bits = EC_GROUP_get_degree(group);
1645             if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS) {
1646                 ERR_raise(ERR_LIB_EC, EC_R_FIELD_TOO_LARGE);
1647                 goto err;
1648             }
1649         }
1650 # endif /* OPENSSL_NO_EC2M */
1651     }
1652
1653     if (group == NULL) {
1654         ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
1655         goto err;
1656     }
1657
1658     /* Optional seed */
1659     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_SEED);
1660     if (ptmp != NULL) {
1661         if (ptmp->data_type != OSSL_PARAM_OCTET_STRING) {
1662             ERR_raise(ERR_LIB_EC, EC_R_INVALID_SEED);
1663             goto err;
1664         }
1665         if (!EC_GROUP_set_seed(group, ptmp->data, ptmp->data_size))
1666             goto err;
1667     }
1668
1669     /* generator base point */
1670     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_GENERATOR);
1671     if (ptmp == NULL
1672         || ptmp->data_type != OSSL_PARAM_OCTET_STRING) {
1673         ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1674         goto err;
1675     }
1676     buf = (const unsigned char *)(ptmp->data);
1677     if ((point = EC_POINT_new(group)) == NULL)
1678         goto err;
1679     EC_GROUP_set_point_conversion_form(group,
1680                                        (point_conversion_form_t)buf[0] & ~0x01);
1681     if (!EC_POINT_oct2point(group, point, buf, ptmp->data_size, bnctx)) {
1682         ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1683         goto err;
1684     }
1685
1686     /* order */
1687     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ORDER);
1688     if (!OSSL_PARAM_get_BN(ptmp, &order)
1689         || (BN_is_negative(order) || BN_is_zero(order))
1690         || (BN_num_bits(order) > (int)field_bits + 1)) { /* Hasse bound */
1691         ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER);
1692         goto err;
1693     }
1694
1695     /* Optional cofactor */
1696     ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_COFACTOR);
1697     if (ptmp != NULL) {
1698         cofactor = BN_CTX_get(bnctx);
1699         if (cofactor == NULL || !OSSL_PARAM_get_BN(ptmp, &cofactor)) {
1700             ERR_raise(ERR_LIB_EC, EC_R_INVALID_COFACTOR);
1701             goto err;
1702         }
1703     }
1704
1705     /* set the generator, order and cofactor (if present) */
1706     if (!EC_GROUP_set_generator(group, point, order, cofactor)) {
1707         ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1708         goto err;
1709     }
1710
1711     named_group = ec_group_explicit_to_named(group, libctx, propq, bnctx);
1712     if (named_group == NULL) {
1713         ERR_raise(ERR_LIB_EC, EC_R_INVALID_NAMED_GROUP_CONVERSION);
1714         goto err;
1715     }
1716     if (named_group == group) {
1717         /*
1718          * If we did not find a named group then the encoding should be explicit
1719          * if it was specified
1720          */
1721         ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ENCODING);
1722         if (ptmp != NULL
1723             && !ossl_ec_encoding_param2id(ptmp, &encoding_flag)) {
1724             ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
1725             goto err;
1726         }
1727         if (encoding_flag == OPENSSL_EC_NAMED_CURVE) {
1728             ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
1729             goto err;
1730         }
1731         EC_GROUP_set_asn1_flag(group, OPENSSL_EC_EXPLICIT_CURVE);
1732     } else {
1733         EC_GROUP_free(group);
1734         group = named_group;
1735     }
1736     ok = 1;
1737  err:
1738     if (!ok) {
1739         EC_GROUP_free(group);
1740         group = NULL;
1741     }
1742     EC_POINT_free(point);
1743     BN_CTX_end(bnctx);
1744     BN_CTX_free(bnctx);
1745
1746     return group;
1747 #endif /* FIPS_MODULE */
1748 }