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