providers/implementations/keymgmt/ec_kmgmt.c

   1 /*
   2  * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * ECDH/ECDSA low level APIs are deprecated for public use, but still ok for
  12  * internal use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <openssl/core_numbers.h>
  17 #include <openssl/core_names.h>
  18 #include <openssl/bn.h>
  19 #include <openssl/objects.h>
  20 #include <openssl/params.h>
  21 #include "crypto/bn.h"
  22 #include "crypto/ec.h"
  23 #include "internal/param_build.h"
  24 #include "prov/implementations.h"
  25 #include "prov/providercommon.h"
  26
  27 static OSSL_OP_keymgmt_new_fn ec_newdata;
  28 static OSSL_OP_keymgmt_free_fn ec_freedata;
  29 static OSSL_OP_keymgmt_get_params_fn ec_get_params;
  30 static OSSL_OP_keymgmt_gettable_params_fn ec_gettable_params;
  31 static OSSL_OP_keymgmt_set_params_fn ec_set_params;
  32 static OSSL_OP_keymgmt_settable_params_fn ec_settable_params;
  33 static OSSL_OP_keymgmt_has_fn ec_has;
  34 static OSSL_OP_keymgmt_match_fn ec_match;
  35 static OSSL_OP_keymgmt_validate_fn ec_validate;
  36 static OSSL_OP_keymgmt_import_fn ec_import;
  37 static OSSL_OP_keymgmt_import_types_fn ec_import_types;
  38 static OSSL_OP_keymgmt_export_fn ec_export;
  39 static OSSL_OP_keymgmt_export_types_fn ec_export_types;
  40 static OSSL_OP_keymgmt_query_operation_name_fn ec_query_operation_name;
  41
  42 #define EC_POSSIBLE_SELECTIONS                 \
  43     (OSSL_KEYMGMT_SELECT_KEYPAIR | OSSL_KEYMGMT_SELECT_ALL_PARAMETERS )
  44
  45 static
  46 const char *ec_query_operation_name(int operation_id)
  47 {
  48     switch (operation_id) {
  49     case OSSL_OP_KEYEXCH:
  50         return "ECDH";
  51 #if 0
  52     case OSSL_OP_SIGNATURE:
  53         return deflt_signature;
  54 #endif
  55     }
  56     return NULL;
  57 }
  58
  59 static ossl_inline
  60 int params_to_domparams(EC_KEY *ec, const OSSL_PARAM params[])
  61 {
  62     const OSSL_PARAM *param_ec_name;
  63     EC_GROUP *ecg = NULL;
  64     char *curve_name = NULL;
  65     int ok = 0;
  66
  67     if (ec == NULL)
  68         return 0;
  69
  70     param_ec_name = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_NAME);
  71     if (param_ec_name == NULL) {
  72         /* explicit parameters */
  73
  74         /*
  75          * TODO(3.0): should we support explicit parameters curves?
  76          */
  77         return 0;
  78     } else {
  79         /* named curve */
  80         int curve_nid;
  81
  82         if (!OSSL_PARAM_get_utf8_string(param_ec_name, &curve_name, 0)
  83                 || curve_name == NULL
  84                 || (curve_nid = OBJ_sn2nid(curve_name)) == NID_undef)
  85             goto err;
  86
  87         if ((ecg = EC_GROUP_new_by_curve_name(curve_nid)) == NULL)
  88             goto err;
  89     }
  90
  91     if (!EC_KEY_set_group(ec, ecg))
  92         goto err;
  93
  94     /*
  95      * TODO(3.0): if the group has changed, should we invalidate the private and
  96      * public key?
  97      */
  98
  99     ok = 1;
 100
 101  err:
 102     OPENSSL_free(curve_name);
 103     EC_GROUP_free(ecg);
 104     return ok;
 105 }
 106
 107 static ossl_inline
 108 int domparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl)
 109 {
 110     const EC_GROUP *ecg;
 111     int curve_nid;
 112
 113     if (ec == NULL)
 114         return 0;
 115
 116     ecg = EC_KEY_get0_group(ec);
 117     if (ecg == NULL)
 118         return 0;
 119
 120     curve_nid = EC_GROUP_get_curve_name(ecg);
 121
 122     if (curve_nid == NID_undef) {
 123         /* explicit parameters */
 124
 125         /*
 126          * TODO(3.0): should we support explicit parameters curves?
 127          */
 128         return 0;
 129     } else {
 130         /* named curve */
 131         const char *curve_name = NULL;
 132
 133         if ((curve_name = OBJ_nid2sn(curve_nid)) == NULL)
 134             return 0;
 135
 136         if (!ossl_param_bld_push_utf8_string(tmpl, OSSL_PKEY_PARAM_EC_NAME, curve_name, 0))
 137             return 0;
 138     }
 139
 140     return 1;
 141 }
 142
 143 /*
 144  * Callers of params_to_key MUST make sure that params_to_domparams has been
 145  * called before!
 146  *
 147  * This function only imports the bare keypair, domain parameters and other
 148  * parameters are imported separately, and domain parameters are required to
 149  * define a keypair.
 150  */
 151 static ossl_inline
 152 int params_to_key(EC_KEY *ec, const OSSL_PARAM params[], int include_private)
 153 {
 154     const OSSL_PARAM *param_priv_key, *param_pub_key;
 155     BIGNUM *priv_key = NULL;
 156     unsigned char *pub_key = NULL;
 157     size_t pub_key_len;
 158     const EC_GROUP *ecg = NULL;
 159     EC_POINT *pub_point = NULL;
 160     int ok = 0;
 161
 162     ecg = EC_KEY_get0_group(ec);
 163     if (ecg == NULL)
 164         return 0;
 165
 166     param_priv_key =
 167         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PRIV_KEY);
 168     param_pub_key =
 169         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PUB_KEY);
 170
 171     /*
 172      * We want to have at least a public key either way, so we end up
 173      * requiring it unconditionally.
 174      */
 175     if (param_pub_key == NULL
 176             || !OSSL_PARAM_get_octet_string(param_pub_key,
 177                                             (void **)&pub_key, 0, &pub_key_len)
 178             || (pub_point = EC_POINT_new(ecg)) == NULL
 179             || !EC_POINT_oct2point(ecg, pub_point,
 180                                    pub_key, pub_key_len, NULL))
 181         goto err;
 182
 183     if (param_priv_key != NULL && include_private) {
 184         int fixed_top;
 185         const BIGNUM *order;
 186
 187         /*
 188          * Key import/export should never leak the bit length of the secret
 189          * scalar in the key.
 190          *
 191          * For this reason, on export we use padded BIGNUMs with fixed length.
 192          *
 193          * When importing we also should make sure that, even if short lived,
 194          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 195          * soon as possible, so that any processing of this BIGNUM might opt for
 196          * constant time implementations in the backend.
 197          *
 198          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 199          * to preallocate the BIGNUM internal buffer to a fixed public size big
 200          * enough that operations performed during the processing never trigger
 201          * a realloc which would leak the size of the scalar through memory
 202          * accesses.
 203          *
 204          * Fixed Length
 205          * ------------
 206          *
 207          * The order of the large prime subgroup of the curve is our choice for
 208          * a fixed public size, as that is generally the upper bound for
 209          * generating a private key in EC cryptosystems and should fit all valid
 210          * secret scalars.
 211          *
 212          * For padding on export we just use the bit length of the order
 213          * converted to bytes (rounding up).
 214          *
 215          * For preallocating the BIGNUM storage we look at the number of "words"
 216          * required for the internal representation of the order, and we
 217          * preallocate 2 extra "words" in case any of the subsequent processing
 218          * might temporarily overflow the order length.
 219          */
 220         order = EC_GROUP_get0_order(ecg);
 221         if (order == NULL || BN_is_zero(order))
 222             goto err;
 223
 224         fixed_top = bn_get_top(order) + 2;
 225
 226         if ((priv_key = BN_new()) == NULL)
 227             goto err;
 228         if (bn_wexpand(priv_key, fixed_top) == NULL)
 229             goto err;
 230         BN_set_flags(priv_key, BN_FLG_CONSTTIME);
 231
 232         if (!OSSL_PARAM_get_BN(param_priv_key, &priv_key))
 233             goto err;
 234     }
 235
 236     if (priv_key != NULL
 237             && !EC_KEY_set_private_key(ec, priv_key))
 238         goto err;
 239
 240     if (!EC_KEY_set_public_key(ec, pub_point))
 241         goto err;
 242
 243     ok = 1;
 244
 245  err:
 246     BN_clear_free(priv_key);
 247     OPENSSL_free(pub_key);
 248     EC_POINT_free(pub_point);
 249     return ok;
 250 }
 251
 252 /*
 253  * Callers of key_to_params MUST make sure that domparams_to_params is also
 254  * called!
 255  *
 256  * This function only exports the bare keypair, domain parameters and other
 257  * parameters are exported separately.
 258  */
 259 static ossl_inline
 260 int key_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl, int include_private)
 261 {
 262     const BIGNUM *priv_key = NULL;
 263     const EC_POINT *pub_point = NULL;
 264     const EC_GROUP *ecg = NULL;
 265     unsigned char *pub_key = NULL;
 266     size_t pub_key_len = 0;
 267     int ret = 0;
 268
 269     if (eckey == NULL)
 270         return 0;
 271
 272     ecg = EC_KEY_get0_group(eckey);
 273     priv_key = EC_KEY_get0_private_key(eckey);
 274     pub_point = EC_KEY_get0_public_key(eckey);
 275
 276     /* group and public_key must be present, priv_key is optional */
 277     if (ecg == NULL || pub_point == NULL)
 278         return 0;
 279     if ((pub_key_len = EC_POINT_point2buf(ecg, pub_point,
 280                                           POINT_CONVERSION_COMPRESSED,
 281                                           &pub_key, NULL)) == 0)
 282         return 0;
 283
 284     if (!ossl_param_bld_push_octet_string(tmpl,
 285                                           OSSL_PKEY_PARAM_PUB_KEY,
 286                                           pub_key, pub_key_len))
 287         goto err;
 288
 289     if (priv_key != NULL && include_private) {
 290         size_t sz;
 291         int ecbits;
 292
 293         /*
 294          * Key import/export should never leak the bit length of the secret
 295          * scalar in the key.
 296          *
 297          * For this reason, on export we use padded BIGNUMs with fixed length.
 298          *
 299          * When importing we also should make sure that, even if short lived,
 300          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 301          * soon as possible, so that any processing of this BIGNUM might opt for
 302          * constant time implementations in the backend.
 303          *
 304          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 305          * to preallocate the BIGNUM internal buffer to a fixed public size big
 306          * enough that operations performed during the processing never trigger
 307          * a realloc which would leak the size of the scalar through memory
 308          * accesses.
 309          *
 310          * Fixed Length
 311          * ------------
 312          *
 313          * The order of the large prime subgroup of the curve is our choice for
 314          * a fixed public size, as that is generally the upper bound for
 315          * generating a private key in EC cryptosystems and should fit all valid
 316          * secret scalars.
 317          *
 318          * For padding on export we just use the bit length of the order
 319          * converted to bytes (rounding up).
 320          *
 321          * For preallocating the BIGNUM storage we look at the number of "words"
 322          * required for the internal representation of the order, and we
 323          * preallocate 2 extra "words" in case any of the subsequent processing
 324          * might temporarily overflow the order length.
 325          */
 326         ecbits = EC_GROUP_order_bits(ecg);
 327         if (ecbits <= 0)
 328             goto err;
 329         sz = (ecbits + 7 ) / 8;
 330         if (!ossl_param_bld_push_BN_pad(tmpl,
 331                                         OSSL_PKEY_PARAM_PRIV_KEY,
 332                                         priv_key, sz))
 333             goto err;
 334     }
 335
 336     ret = 1;
 337
 338  err:
 339     OPENSSL_free(pub_key);
 340     return ret;
 341 }
 342
 343 static ossl_inline
 344 int ec_set_param_ecdh_cofactor_mode(EC_KEY *ec, const OSSL_PARAM *p)
 345 {
 346     const EC_GROUP *ecg = EC_KEY_get0_group(ec);
 347     const BIGNUM *cofactor;
 348     int mode;
 349
 350     if (!OSSL_PARAM_get_int(p, &mode))
 351         return 0;
 352
 353     /*
 354      * mode can be only 0 for disable, or 1 for enable here.
 355      *
 356      * This is in contrast with the same parameter on an ECDH EVP_PKEY_CTX that
 357      * also supports mode == -1 with the meaning of "reset to the default for
 358      * the associated key".
 359      */
 360     if (mode < 0 || mode > 1)
 361         return 0;
 362
 363     if ((cofactor = EC_GROUP_get0_cofactor(ecg)) == NULL )
 364         return 0;
 365
 366     /* ECDH cofactor mode has no effect if cofactor is 1 */
 367     if (BN_is_one(cofactor))
 368         return 1;
 369
 370     if (mode == 1)
 371         EC_KEY_set_flags(ec, EC_FLAG_COFACTOR_ECDH);
 372     else if (mode == 0)
 373         EC_KEY_clear_flags(ec, EC_FLAG_COFACTOR_ECDH);
 374
 375     return 1;
 376 }
 377
 378 static ossl_inline
 379 int params_to_otherparams(EC_KEY *ec, const OSSL_PARAM params[])
 380 {
 381     const OSSL_PARAM *p;
 382
 383     if (ec == NULL)
 384         return 0;
 385
 386     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
 387     if (p != NULL && !ec_set_param_ecdh_cofactor_mode(ec, p))
 388         return 0;
 389
 390     return 1;
 391 }
 392
 393 static ossl_inline
 394 int otherparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl)
 395 {
 396     int ecdh_cofactor_mode = 0;
 397
 398     if (ec == NULL)
 399         return 0;
 400
 401     ecdh_cofactor_mode =
 402         (EC_KEY_get_flags(ec) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 403     if (!ossl_param_bld_push_int(tmpl,
 404                 OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 405                 ecdh_cofactor_mode))
 406         return 0;
 407
 408     return 1;
 409 }
 410
 411 static
 412 void *ec_newdata(void *provctx)
 413 {
 414     return EC_KEY_new();
 415 }
 416
 417 static
 418 void ec_freedata(void *keydata)
 419 {
 420     EC_KEY_free(keydata);
 421 }
 422
 423 static
 424 int ec_has(void *keydata, int selection)
 425 {
 426     EC_KEY *ec = keydata;
 427     int ok = 0;
 428
 429     if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 430         ok = 1;
 431
 432     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 433         ok = ok && (EC_KEY_get0_public_key(ec) != NULL);
 434     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 435         ok = ok && (EC_KEY_get0_private_key(ec) != NULL);
 436     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 437         ok = ok && (EC_KEY_get0_group(ec) != NULL);
 438     /*
 439      * We consider OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS to always be available,
 440      * so no extra check is needed other than the previous one against
 441      * EC_POSSIBLE_SELECTIONS.
 442      */
 443
 444     return ok;
 445 }
 446
 447 static int ec_match(const void *keydata1, const void *keydata2, int selection)
 448 {
 449     const EC_KEY *ec1 = keydata1;
 450     const EC_KEY *ec2 = keydata2;
 451     const EC_GROUP *group_a = EC_KEY_get0_group(ec1);
 452     const EC_GROUP *group_b = EC_KEY_get0_group(ec2);
 453     int ok = 1;
 454
 455     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 456         ok = ok && group_a != NULL && group_b != NULL
 457             && EC_GROUP_cmp(group_a, group_b, NULL) == 0;
 458     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {
 459         const BIGNUM *pa = EC_KEY_get0_private_key(ec1);
 460         const BIGNUM *pb = EC_KEY_get0_private_key(ec2);
 461
 462         ok = ok && BN_cmp(pa, pb) == 0;
 463     }
 464     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0) {
 465         const EC_POINT *pa = EC_KEY_get0_public_key(ec1);
 466         const EC_POINT *pb = EC_KEY_get0_public_key(ec2);
 467
 468         ok = ok && EC_POINT_cmp(group_b, pa, pb, NULL);
 469     }
 470     return ok;
 471 }
 472
 473 static
 474 int ec_import(void *keydata, int selection, const OSSL_PARAM params[])
 475 {
 476     EC_KEY *ec = keydata;
 477     int ok = 1;
 478
 479     if (ec == NULL)
 480         return 0;
 481
 482     /*
 483      * In this implementation, we can export/import only keydata in the
 484      * following combinations:
 485      *   - domain parameters only
 486      *   - public key with associated domain parameters (+optional other params)
 487      *   - private key with associated public key and domain parameters
 488      *         (+optional other params)
 489      *
 490      * This means:
 491      *   - domain parameters must always be requested
 492      *   - private key must be requested alongside public key
 493      *   - other parameters must be requested only alongside a key
 494      */
 495     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 496         return 0;
 497     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 498             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 499         return 0;
 500     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
 501             && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
 502         return 0;
 503
 504     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 505         ok = ok && params_to_domparams(ec, params);
 506     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 507         int include_private =
 508             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 509
 510         ok = ok && params_to_key(ec, params, include_private);
 511     }
 512     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 513         ok = ok && params_to_otherparams(ec, params);
 514
 515     return ok;
 516 }
 517
 518 static
 519 int ec_export(void *keydata, int selection, OSSL_CALLBACK *param_cb,
 520               void *cbarg)
 521 {
 522     EC_KEY *ec = keydata;
 523     OSSL_PARAM_BLD tmpl;
 524     OSSL_PARAM *params = NULL;
 525     int ok = 1;
 526
 527     if (ec == NULL)
 528         return 0;
 529
 530     /*
 531      * In this implementation, we can export/import only keydata in the
 532      * following combinations:
 533      *   - domain parameters only
 534      *   - public key with associated domain parameters (+optional other params)
 535      *   - private key with associated public key and domain parameters
 536      *         (+optional other params)
 537      *
 538      * This means:
 539      *   - domain parameters must always be requested
 540      *   - private key must be requested alongside public key
 541      *   - other parameters must be requested only alongside a key
 542      */
 543     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 544         return 0;
 545     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 546             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 547         return 0;
 548     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
 549             && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
 550         return 0;
 551
 552     ossl_param_bld_init(&tmpl);
 553
 554     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 555         ok = ok && domparams_to_params(ec, &tmpl);
 556     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 557         int include_private =
 558             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 559
 560         ok = ok && key_to_params(ec, &tmpl, include_private);
 561     }
 562     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 563         ok = ok && otherparams_to_params(ec, &tmpl);
 564
 565     if (!ok
 566         || (params = ossl_param_bld_to_param(&tmpl)) == NULL)
 567         return 0;
 568
 569     ok = param_cb(params, cbarg);
 570     ossl_param_bld_free(params);
 571     return ok;
 572 }
 573
 574 /* IMEXPORT = IMPORT + EXPORT */
 575
 576 # define EC_IMEXPORTABLE_DOM_PARAMETERS                          \
 577     OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_NAME, NULL, 0)
 578 # define EC_IMEXPORTABLE_PUBLIC_KEY                              \
 579     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_PUB_KEY, NULL, 0)
 580 # define EC_IMEXPORTABLE_PRIVATE_KEY                             \
 581     OSSL_PARAM_BN(OSSL_PKEY_PARAM_PRIV_KEY, NULL, 0)
 582 # define EC_IMEXPORTABLE_OTHER_PARAMETERS                        \
 583     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL)
 584
 585 /*
 586  * Include all the possible combinations of OSSL_PARAM arrays for
 587  * ec_imexport_types().
 588  *
 589  * They are in a separate file as it is ~100 lines of unreadable and
 590  * uninteresting machine generated stuff.
 591  *
 592  * TODO(3.0): the generated list looks quite ugly, as to cover all possible
 593  * combinations of the bits in `selection`, it also includes combinations that
 594  * are not really useful: we might want to consider alternatives to this
 595  * solution.
 596  */
 597 #include "ec_kmgmt_imexport.inc"
 598
 599 static ossl_inline
 600 const OSSL_PARAM *ec_imexport_types(int selection)
 601 {
 602     int type_select = 0;
 603
 604     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 605         type_select += 1;
 606     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 607         type_select += 2;
 608     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 609         type_select += 4;
 610     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 611         type_select += 8;
 612     return ec_types[type_select];
 613 }
 614
 615 static
 616 const OSSL_PARAM *ec_import_types(int selection)
 617 {
 618     return ec_imexport_types(selection);
 619 }
 620
 621 static
 622 const OSSL_PARAM *ec_export_types(int selection)
 623 {
 624     return ec_imexport_types(selection);
 625 }
 626
 627 static
 628 int ec_get_params(void *key, OSSL_PARAM params[])
 629 {
 630     EC_KEY *eck = key;
 631     const EC_GROUP *ecg = NULL;
 632     OSSL_PARAM *p;
 633
 634     ecg = EC_KEY_get0_group(eck);
 635     if (ecg == NULL)
 636         return 0;
 637
 638     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_MAX_SIZE)) != NULL
 639         && !OSSL_PARAM_set_int(p, ECDSA_size(eck)))
 640         return 0;
 641     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_BITS)) != NULL
 642         && !OSSL_PARAM_set_int(p, EC_GROUP_order_bits(ecg)))
 643         return 0;
 644     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_SECURITY_BITS)) != NULL) {
 645         int ecbits, sec_bits;
 646
 647         ecbits = EC_GROUP_order_bits(ecg);
 648
 649         /*
 650          * The following estimates are based on the values published
 651          * in Table 2 of "NIST Special Publication 800-57 Part 1 Revision 4"
 652          * at http://dx.doi.org/10.6028/NIST.SP.800-57pt1r4 .
 653          *
 654          * Note that the above reference explicitly categorizes algorithms in a
 655          * discrete set of values {80, 112, 128, 192, 256}, and that it is
 656          * relevant only for NIST approved Elliptic Curves, while OpenSSL
 657          * applies the same logic also to other curves.
 658          *
 659          * Classifications produced by other standardazing bodies might differ,
 660          * so the results provided for "bits of security" by this provider are
 661          * to be considered merely indicative, and it is the users'
 662          * responsibility to compare these values against the normative
 663          * references that may be relevant for their intent and purposes.
 664          */
 665         if (ecbits >= 512)
 666             sec_bits = 256;
 667         else if (ecbits >= 384)
 668             sec_bits = 192;
 669         else if (ecbits >= 256)
 670             sec_bits = 128;
 671         else if (ecbits >= 224)
 672             sec_bits = 112;
 673         else if (ecbits >= 160)
 674             sec_bits = 80;
 675         else
 676             sec_bits = ecbits / 2;
 677
 678         if (!OSSL_PARAM_set_int(p, sec_bits))
 679             return 0;
 680     }
 681
 682     p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
 683     if (p != NULL) {
 684         int ecdh_cofactor_mode = 0;
 685
 686         ecdh_cofactor_mode =
 687             (EC_KEY_get_flags(eck) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 688
 689         if (!OSSL_PARAM_set_int(p, ecdh_cofactor_mode))
 690             return 0;
 691     }
 692
 693     return 1;
 694 }
 695
 696 static const OSSL_PARAM ec_known_gettable_params[] = {
 697     OSSL_PARAM_int(OSSL_PKEY_PARAM_BITS, NULL),
 698     OSSL_PARAM_int(OSSL_PKEY_PARAM_SECURITY_BITS, NULL),
 699     OSSL_PARAM_int(OSSL_PKEY_PARAM_MAX_SIZE, NULL),
 700     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 701     OSSL_PARAM_END
 702 };
 703
 704 static
 705 const OSSL_PARAM *ec_gettable_params(void)
 706 {
 707     return ec_known_gettable_params;
 708 }
 709
 710 static const OSSL_PARAM ec_known_settable_params[] = {
 711     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 712     OSSL_PARAM_END
 713 };
 714
 715 static
 716 const OSSL_PARAM *ec_settable_params(void)
 717 {
 718     return ec_known_settable_params;
 719 }
 720
 721 static
 722 int ec_set_params(void *key, const OSSL_PARAM params[])
 723 {
 724     EC_KEY *eck = key;
 725     const OSSL_PARAM *p;
 726
 727     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
 728     if (p != NULL && !ec_set_param_ecdh_cofactor_mode(eck, p))
 729         return 0;
 730
 731     return 1;
 732 }
 733
 734 static
 735 int ec_validate(void *keydata, int selection)
 736 {
 737     EC_KEY *eck = keydata;
 738     int ok = 0;
 739     BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(eck));
 740
 741     if (ctx == NULL)
 742         return 0;
 743
 744     if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 745         ok = 1;
 746
 747     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 748         ok = ok && EC_GROUP_check(EC_KEY_get0_group(eck), ctx);
 749
 750     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 751         ok = ok && ec_key_public_check(eck, ctx);
 752
 753     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 754         ok = ok && ec_key_private_check(eck);
 755
 756     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == OSSL_KEYMGMT_SELECT_KEYPAIR)
 757         ok = ok && ec_key_pairwise_check(eck, ctx);
 758
 759     BN_CTX_free(ctx);
 760     return ok;
 761 }
 762
 763 const OSSL_DISPATCH ec_keymgmt_functions[] = {
 764     { OSSL_FUNC_KEYMGMT_NEW, (void (*)(void))ec_newdata },
 765     { OSSL_FUNC_KEYMGMT_FREE, (void (*)(void))ec_freedata },
 766     { OSSL_FUNC_KEYMGMT_GET_PARAMS, (void (*) (void))ec_get_params },
 767     { OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS, (void (*) (void))ec_gettable_params },
 768     { OSSL_FUNC_KEYMGMT_SET_PARAMS, (void (*) (void))ec_set_params },
 769     { OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS, (void (*) (void))ec_settable_params },
 770     { OSSL_FUNC_KEYMGMT_HAS, (void (*)(void))ec_has },
 771     { OSSL_FUNC_KEYMGMT_MATCH, (void (*)(void))ec_match },
 772     { OSSL_FUNC_KEYMGMT_VALIDATE, (void (*)(void))ec_validate },
 773     { OSSL_FUNC_KEYMGMT_IMPORT, (void (*)(void))ec_import },
 774     { OSSL_FUNC_KEYMGMT_IMPORT_TYPES, (void (*)(void))ec_import_types },
 775     { OSSL_FUNC_KEYMGMT_EXPORT, (void (*)(void))ec_export },
 776     { OSSL_FUNC_KEYMGMT_EXPORT_TYPES, (void (*)(void))ec_export_types },
 777     { OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME,
 778         (void (*)(void))ec_query_operation_name },
 779     { 0, NULL }
 780 };