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/err.h>
  20 #include <openssl/objects.h>
  21 #include "crypto/bn.h"
  22 #include "crypto/ec.h"
  23 #include "prov/implementations.h"
  24 #include "prov/providercommon.h"
  25 #include "prov/providercommonerr.h"
  26 #include "prov/provider_ctx.h"
  27 #include "internal/param_build_set.h"
  28
  29 static OSSL_OP_keymgmt_new_fn ec_newdata;
  30 static OSSL_OP_keymgmt_gen_init_fn ec_gen_init;
  31 static OSSL_OP_keymgmt_gen_set_template_fn ec_gen_set_template;
  32 static OSSL_OP_keymgmt_gen_set_params_fn ec_gen_set_params;
  33 static OSSL_OP_keymgmt_gen_settable_params_fn ec_gen_settable_params;
  34 static OSSL_OP_keymgmt_gen_fn ec_gen;
  35 static OSSL_OP_keymgmt_gen_cleanup_fn ec_gen_cleanup;
  36 static OSSL_OP_keymgmt_free_fn ec_freedata;
  37 static OSSL_OP_keymgmt_get_params_fn ec_get_params;
  38 static OSSL_OP_keymgmt_gettable_params_fn ec_gettable_params;
  39 static OSSL_OP_keymgmt_set_params_fn ec_set_params;
  40 static OSSL_OP_keymgmt_settable_params_fn ec_settable_params;
  41 static OSSL_OP_keymgmt_has_fn ec_has;
  42 static OSSL_OP_keymgmt_match_fn ec_match;
  43 static OSSL_OP_keymgmt_validate_fn ec_validate;
  44 static OSSL_OP_keymgmt_import_fn ec_import;
  45 static OSSL_OP_keymgmt_import_types_fn ec_import_types;
  46 static OSSL_OP_keymgmt_export_fn ec_export;
  47 static OSSL_OP_keymgmt_export_types_fn ec_export_types;
  48 static OSSL_OP_keymgmt_query_operation_name_fn ec_query_operation_name;
  49
  50 #define EC_DEFAULT_MD "SHA256"
  51 #define EC_POSSIBLE_SELECTIONS                                                 \
  52     (OSSL_KEYMGMT_SELECT_KEYPAIR | OSSL_KEYMGMT_SELECT_ALL_PARAMETERS)
  53
  54 static
  55 const char *ec_query_operation_name(int operation_id)
  56 {
  57     switch (operation_id) {
  58     case OSSL_OP_KEYEXCH:
  59         return "ECDH";
  60     case OSSL_OP_SIGNATURE:
  61         return "ECDSA";
  62     }
  63     return NULL;
  64 }
  65
  66 static ossl_inline
  67 int domparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl,
  68                         OSSL_PARAM params[])
  69 {
  70     const EC_GROUP *ecg;
  71     int curve_nid;
  72
  73     if (ec == NULL)
  74         return 0;
  75
  76     ecg = EC_KEY_get0_group(ec);
  77     if (ecg == NULL)
  78         return 0;
  79
  80     curve_nid = EC_GROUP_get_curve_name(ecg);
  81
  82     if (curve_nid == NID_undef) {
  83         /* TODO(3.0): should we support explicit parameters curves? */
  84         return 0;
  85     } else {
  86         /* named curve */
  87         const char *curve_name = NULL;
  88
  89         if ((curve_name = ec_curve_nid2name(curve_nid)) == NULL)
  90             return 0;
  91         if (!ossl_param_build_set_utf8_string(tmpl, params,
  92                                               OSSL_PKEY_PARAM_EC_NAME,
  93                                               curve_name))
  94
  95             return 0;
  96     }
  97
  98     return 1;
  99 }
 100
 101 /*
 102  * Callers of key_to_params MUST make sure that domparams_to_params is also
 103  * called!
 104  *
 105  * This function only exports the bare keypair, domain parameters and other
 106  * parameters are exported separately.
 107  */
 108 static ossl_inline
 109 int key_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl,
 110                   OSSL_PARAM params[], int include_private,
 111                   unsigned char **pub_key)
 112 {
 113     const BIGNUM *priv_key = NULL;
 114     const EC_POINT *pub_point = NULL;
 115     const EC_GROUP *ecg = NULL;
 116     size_t pub_key_len = 0;
 117     int ret = 0;
 118     BN_CTX *bnctx = NULL;
 119
 120     if (eckey == NULL
 121         || (ecg = EC_KEY_get0_group(eckey)) == NULL)
 122         return 0;
 123
 124     priv_key = EC_KEY_get0_private_key(eckey);
 125     pub_point = EC_KEY_get0_public_key(eckey);
 126
 127     if (pub_point != NULL) {
 128         /*
 129          * EC_POINT_point2buf() can generate random numbers in some
 130          * implementations so we need to ensure we use the correct libctx.
 131          */
 132         bnctx = BN_CTX_new_ex(ec_key_get_libctx(eckey));
 133         if (bnctx == NULL)
 134             goto err;
 135
 136         /* convert pub_point to a octet string according to the SECG standard */
 137         if ((pub_key_len = EC_POINT_point2buf(ecg, pub_point,
 138                                               POINT_CONVERSION_COMPRESSED,
 139                                               pub_key, bnctx)) == 0
 140             || !ossl_param_build_set_octet_string(tmpl, params,
 141                                                   OSSL_PKEY_PARAM_PUB_KEY,
 142                                                   *pub_key, pub_key_len))
 143             goto err;
 144     }
 145
 146     if (priv_key != NULL && include_private) {
 147         size_t sz;
 148         int ecbits;
 149
 150         /*
 151          * Key import/export should never leak the bit length of the secret
 152          * scalar in the key.
 153          *
 154          * For this reason, on export we use padded BIGNUMs with fixed length.
 155          *
 156          * When importing we also should make sure that, even if short lived,
 157          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 158          * soon as possible, so that any processing of this BIGNUM might opt for
 159          * constant time implementations in the backend.
 160          *
 161          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 162          * to preallocate the BIGNUM internal buffer to a fixed public size big
 163          * enough that operations performed during the processing never trigger
 164          * a realloc which would leak the size of the scalar through memory
 165          * accesses.
 166          *
 167          * Fixed Length
 168          * ------------
 169          *
 170          * The order of the large prime subgroup of the curve is our choice for
 171          * a fixed public size, as that is generally the upper bound for
 172          * generating a private key in EC cryptosystems and should fit all valid
 173          * secret scalars.
 174          *
 175          * For padding on export we just use the bit length of the order
 176          * converted to bytes (rounding up).
 177          *
 178          * For preallocating the BIGNUM storage we look at the number of "words"
 179          * required for the internal representation of the order, and we
 180          * preallocate 2 extra "words" in case any of the subsequent processing
 181          * might temporarily overflow the order length.
 182          */
 183         ecbits = EC_GROUP_order_bits(ecg);
 184         if (ecbits <= 0)
 185             goto err;
 186         sz = (ecbits + 7 ) / 8;
 187
 188         if (!ossl_param_build_set_bn_pad(tmpl, params,
 189                                          OSSL_PKEY_PARAM_PRIV_KEY,
 190                                          priv_key, sz))
 191             goto err;
 192     }
 193     ret = 1;
 194  err:
 195     BN_CTX_free(bnctx);
 196     return ret;
 197 }
 198
 199 static ossl_inline
 200 int otherparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl,
 201                           OSSL_PARAM params[])
 202 {
 203     int ecdh_cofactor_mode = 0;
 204
 205     if (ec == NULL)
 206         return 0;
 207
 208     ecdh_cofactor_mode =
 209         (EC_KEY_get_flags(ec) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 210     return ossl_param_build_set_int(tmpl, params,
 211                                     OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 212                                     ecdh_cofactor_mode);
 213 }
 214
 215 static
 216 void *ec_newdata(void *provctx)
 217 {
 218     return EC_KEY_new_ex(PROV_LIBRARY_CONTEXT_OF(provctx));
 219 }
 220
 221 static
 222 void ec_freedata(void *keydata)
 223 {
 224     EC_KEY_free(keydata);
 225 }
 226
 227 static
 228 int ec_has(void *keydata, int selection)
 229 {
 230     EC_KEY *ec = keydata;
 231     int ok = 0;
 232
 233     if (ec != NULL) {
 234         if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 235             ok = 1;
 236
 237         if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 238             ok = ok && (EC_KEY_get0_public_key(ec) != NULL);
 239         if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 240             ok = ok && (EC_KEY_get0_private_key(ec) != NULL);
 241         if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 242             ok = ok && (EC_KEY_get0_group(ec) != NULL);
 243         /*
 244          * We consider OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS to always be
 245          * available, so no extra check is needed other than the previous one
 246          * against EC_POSSIBLE_SELECTIONS.
 247          */
 248     }
 249     return ok;
 250 }
 251
 252 static int ec_match(const void *keydata1, const void *keydata2, int selection)
 253 {
 254     const EC_KEY *ec1 = keydata1;
 255     const EC_KEY *ec2 = keydata2;
 256     const EC_GROUP *group_a = EC_KEY_get0_group(ec1);
 257     const EC_GROUP *group_b = EC_KEY_get0_group(ec2);
 258     int ok = 1;
 259
 260     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 261         ok = ok && group_a != NULL && group_b != NULL
 262             && EC_GROUP_cmp(group_a, group_b, NULL) == 0;
 263     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {
 264         const BIGNUM *pa = EC_KEY_get0_private_key(ec1);
 265         const BIGNUM *pb = EC_KEY_get0_private_key(ec2);
 266
 267         ok = ok && BN_cmp(pa, pb) == 0;
 268     }
 269     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0) {
 270         const EC_POINT *pa = EC_KEY_get0_public_key(ec1);
 271         const EC_POINT *pb = EC_KEY_get0_public_key(ec2);
 272
 273         ok = ok && EC_POINT_cmp(group_b, pa, pb, NULL);
 274     }
 275     return ok;
 276 }
 277
 278 static
 279 int ec_import(void *keydata, int selection, const OSSL_PARAM params[])
 280 {
 281     EC_KEY *ec = keydata;
 282     int ok = 1;
 283
 284     if (ec == NULL)
 285         return 0;
 286
 287     /*
 288      * In this implementation, we can export/import only keydata in the
 289      * following combinations:
 290      *   - domain parameters only
 291      *   - public key with associated domain parameters (+optional other params)
 292      *   - private key with associated public key and domain parameters
 293      *         (+optional other params)
 294      *
 295      * This means:
 296      *   - domain parameters must always be requested
 297      *   - private key must be requested alongside public key
 298      *   - other parameters must be requested only alongside a key
 299      */
 300     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 301         return 0;
 302     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 303             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 304         return 0;
 305     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
 306             && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
 307         return 0;
 308
 309     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 310         ok = ok && ec_key_domparams_fromdata(ec, params);
 311     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 312         int include_private =
 313             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 314
 315         ok = ok && ec_key_fromdata(ec, params, include_private);
 316     }
 317     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 318         ok = ok && ec_key_otherparams_fromdata(ec, params);
 319
 320     return ok;
 321 }
 322
 323 static
 324 int ec_export(void *keydata, int selection, OSSL_CALLBACK *param_cb,
 325               void *cbarg)
 326 {
 327     EC_KEY *ec = keydata;
 328     OSSL_PARAM_BLD *tmpl;
 329     OSSL_PARAM *params = NULL;
 330     unsigned char *pub_key = NULL;
 331     int ok = 1;
 332
 333     if (ec == NULL)
 334         return 0;
 335
 336     /*
 337      * In this implementation, we can export/import only keydata in the
 338      * following combinations:
 339      *   - domain parameters only
 340      *   - public key with associated domain parameters (+optional other params)
 341      *   - private key with associated public key and domain parameters
 342      *         (+optional other params)
 343      *
 344      * This means:
 345      *   - domain parameters must always be requested
 346      *   - private key must be requested alongside public key
 347      *   - other parameters must be requested only alongside a key
 348      */
 349     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 350         return 0;
 351     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 352             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 353         return 0;
 354     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
 355             && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
 356         return 0;
 357
 358     tmpl = OSSL_PARAM_BLD_new();
 359     if (tmpl == NULL)
 360         return 0;
 361
 362     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 363         ok = ok && domparams_to_params(ec, tmpl, NULL);
 364
 365     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 366         int include_private =
 367             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 368
 369         ok = ok && key_to_params(ec, tmpl, NULL, include_private, &pub_key);
 370     }
 371     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 372         ok = ok && otherparams_to_params(ec, tmpl, NULL);
 373
 374     if (ok && (params = OSSL_PARAM_BLD_to_param(tmpl)) != NULL)
 375         ok = param_cb(params, cbarg);
 376
 377     OSSL_PARAM_BLD_free_params(params);
 378     OSSL_PARAM_BLD_free(tmpl);
 379     OPENSSL_free(pub_key);
 380     return ok;
 381 }
 382
 383 /* IMEXPORT = IMPORT + EXPORT */
 384
 385 # define EC_IMEXPORTABLE_DOM_PARAMETERS                          \
 386     OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_NAME, NULL, 0)
 387 # define EC_IMEXPORTABLE_PUBLIC_KEY                              \
 388     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_PUB_KEY, NULL, 0)
 389 # define EC_IMEXPORTABLE_PRIVATE_KEY                             \
 390     OSSL_PARAM_BN(OSSL_PKEY_PARAM_PRIV_KEY, NULL, 0)
 391 # define EC_IMEXPORTABLE_OTHER_PARAMETERS                        \
 392     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL)
 393
 394 /*
 395  * Include all the possible combinations of OSSL_PARAM arrays for
 396  * ec_imexport_types().
 397  *
 398  * They are in a separate file as it is ~100 lines of unreadable and
 399  * uninteresting machine generated stuff.
 400  *
 401  * TODO(3.0): the generated list looks quite ugly, as to cover all possible
 402  * combinations of the bits in `selection`, it also includes combinations that
 403  * are not really useful: we might want to consider alternatives to this
 404  * solution.
 405  */
 406 #include "ec_kmgmt_imexport.inc"
 407
 408 static ossl_inline
 409 const OSSL_PARAM *ec_imexport_types(int selection)
 410 {
 411     int type_select = 0;
 412
 413     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 414         type_select += 1;
 415     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 416         type_select += 2;
 417     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 418         type_select += 4;
 419     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 420         type_select += 8;
 421     return ec_types[type_select];
 422 }
 423
 424 static
 425 const OSSL_PARAM *ec_import_types(int selection)
 426 {
 427     return ec_imexport_types(selection);
 428 }
 429
 430 static
 431 const OSSL_PARAM *ec_export_types(int selection)
 432 {
 433     return ec_imexport_types(selection);
 434 }
 435
 436 static
 437 int ec_get_params(void *key, OSSL_PARAM params[])
 438 {
 439     int ret;
 440     EC_KEY *eck = key;
 441     const EC_GROUP *ecg = NULL;
 442     OSSL_PARAM *p;
 443     unsigned char *pub_key = NULL;
 444
 445     ecg = EC_KEY_get0_group(eck);
 446     if (ecg == NULL)
 447         return 0;
 448
 449     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_MAX_SIZE)) != NULL
 450         && !OSSL_PARAM_set_int(p, ECDSA_size(eck)))
 451         return 0;
 452     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_BITS)) != NULL
 453         && !OSSL_PARAM_set_int(p, EC_GROUP_order_bits(ecg)))
 454         return 0;
 455     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_SECURITY_BITS)) != NULL) {
 456         int ecbits, sec_bits;
 457
 458         ecbits = EC_GROUP_order_bits(ecg);
 459
 460         /*
 461          * The following estimates are based on the values published
 462          * in Table 2 of "NIST Special Publication 800-57 Part 1 Revision 4"
 463          * at http://dx.doi.org/10.6028/NIST.SP.800-57pt1r4 .
 464          *
 465          * Note that the above reference explicitly categorizes algorithms in a
 466          * discrete set of values {80, 112, 128, 192, 256}, and that it is
 467          * relevant only for NIST approved Elliptic Curves, while OpenSSL
 468          * applies the same logic also to other curves.
 469          *
 470          * Classifications produced by other standardazing bodies might differ,
 471          * so the results provided for "bits of security" by this provider are
 472          * to be considered merely indicative, and it is the users'
 473          * responsibility to compare these values against the normative
 474          * references that may be relevant for their intent and purposes.
 475          */
 476         if (ecbits >= 512)
 477             sec_bits = 256;
 478         else if (ecbits >= 384)
 479             sec_bits = 192;
 480         else if (ecbits >= 256)
 481             sec_bits = 128;
 482         else if (ecbits >= 224)
 483             sec_bits = 112;
 484         else if (ecbits >= 160)
 485             sec_bits = 80;
 486         else
 487             sec_bits = ecbits / 2;
 488
 489         if (!OSSL_PARAM_set_int(p, sec_bits))
 490             return 0;
 491     }
 492
 493     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_DEFAULT_DIGEST)) != NULL
 494         && !OSSL_PARAM_set_utf8_string(p, EC_DEFAULT_MD))
 495         return 0;
 496
 497     p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
 498     if (p != NULL) {
 499         int ecdh_cofactor_mode = 0;
 500
 501         ecdh_cofactor_mode =
 502             (EC_KEY_get_flags(eck) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 503
 504         if (!OSSL_PARAM_set_int(p, ecdh_cofactor_mode))
 505             return 0;
 506     }
 507     ret = domparams_to_params(eck, NULL, params)
 508           && key_to_params(eck, NULL, params, 1, &pub_key)
 509           && otherparams_to_params(eck, NULL, params);
 510     OPENSSL_free(pub_key);
 511     return ret;
 512 }
 513
 514 static const OSSL_PARAM ec_known_gettable_params[] = {
 515     OSSL_PARAM_int(OSSL_PKEY_PARAM_BITS, NULL),
 516     OSSL_PARAM_int(OSSL_PKEY_PARAM_SECURITY_BITS, NULL),
 517     OSSL_PARAM_int(OSSL_PKEY_PARAM_MAX_SIZE, NULL),
 518     EC_IMEXPORTABLE_DOM_PARAMETERS,
 519     EC_IMEXPORTABLE_PUBLIC_KEY,
 520     EC_IMEXPORTABLE_PRIVATE_KEY,
 521     EC_IMEXPORTABLE_OTHER_PARAMETERS,
 522     OSSL_PARAM_END
 523 };
 524
 525 static
 526 const OSSL_PARAM *ec_gettable_params(void)
 527 {
 528     return ec_known_gettable_params;
 529 }
 530
 531 static const OSSL_PARAM ec_known_settable_params[] = {
 532     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 533     OSSL_PARAM_END
 534 };
 535
 536 static
 537 const OSSL_PARAM *ec_settable_params(void)
 538 {
 539     return ec_known_settable_params;
 540 }
 541
 542 static
 543 int ec_set_params(void *key, const OSSL_PARAM params[])
 544 {
 545     EC_KEY *eck = key;
 546
 547     return ec_key_otherparams_fromdata(eck, params);
 548 }
 549
 550 static
 551 int ec_validate(void *keydata, int selection)
 552 {
 553     EC_KEY *eck = keydata;
 554     int ok = 0;
 555     BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(eck));
 556
 557     if (ctx == NULL)
 558         return 0;
 559
 560     if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 561         ok = 1;
 562
 563     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 564         ok = ok && EC_GROUP_check(EC_KEY_get0_group(eck), ctx);
 565
 566     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 567         ok = ok && ec_key_public_check(eck, ctx);
 568
 569     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 570         ok = ok && ec_key_private_check(eck);
 571
 572     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == OSSL_KEYMGMT_SELECT_KEYPAIR)
 573         ok = ok && ec_key_pairwise_check(eck, ctx);
 574
 575     BN_CTX_free(ctx);
 576     return ok;
 577 }
 578
 579 struct ec_gen_ctx {
 580     OPENSSL_CTX *libctx;
 581     EC_GROUP *gen_group;
 582     int selection;
 583     int ecdh_mode;
 584 };
 585
 586 static void *ec_gen_init(void *provctx, int selection)
 587 {
 588     OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
 589     struct ec_gen_ctx *gctx = NULL;
 590
 591     if ((selection & (EC_POSSIBLE_SELECTIONS)) == 0)
 592         return NULL;
 593
 594     if ((gctx = OPENSSL_zalloc(sizeof(*gctx))) != NULL) {
 595         gctx->libctx = libctx;
 596         gctx->gen_group = NULL;
 597         gctx->selection = selection;
 598         gctx->ecdh_mode = 0;
 599     }
 600     return gctx;
 601 }
 602
 603 static int ec_gen_set_group(void *genctx, int nid)
 604 {
 605     struct ec_gen_ctx *gctx = genctx;
 606     EC_GROUP *group;
 607
 608     group = EC_GROUP_new_by_curve_name_ex(gctx->libctx, nid);
 609     if (group == NULL) {
 610         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
 611         return 0;
 612     }
 613     EC_GROUP_free(gctx->gen_group);
 614     gctx->gen_group = group;
 615     return 1;
 616 }
 617 static int ec_gen_set_template(void *genctx, void *templ)
 618 {
 619     struct ec_gen_ctx *gctx = genctx;
 620     EC_KEY *ec = templ;
 621     const EC_GROUP *ec_group;
 622
 623     if (gctx == NULL || ec == NULL)
 624         return 0;
 625     if ((ec_group = EC_KEY_get0_group(ec)) == NULL)
 626         return 0;
 627     return ec_gen_set_group(gctx, EC_GROUP_get_curve_name(ec_group));
 628 }
 629
 630 static int ec_gen_set_params(void *genctx, const OSSL_PARAM params[])
 631 {
 632     struct ec_gen_ctx *gctx = genctx;
 633     const OSSL_PARAM *p;
 634
 635     if ((p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH))
 636         != NULL) {
 637         if (!OSSL_PARAM_get_int(p, &gctx->ecdh_mode))
 638             return 0;
 639     }
 640     if ((p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_NAME))
 641         != NULL) {
 642         const char *curve_name = NULL;
 643         int ret = 0;
 644
 645         switch (p->data_type) {
 646         case OSSL_PARAM_UTF8_STRING:
 647             /* The OSSL_PARAM functions have no support for this */
 648             curve_name = p->data;
 649             ret = (curve_name != NULL);
 650             break;
 651         case OSSL_PARAM_UTF8_PTR:
 652             ret = OSSL_PARAM_get_utf8_ptr(p, &curve_name);
 653             break;
 654         }
 655
 656         if (ret) {
 657             int nid = ec_curve_name2nid(curve_name);
 658
 659             if (nid == NID_undef) {
 660                 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
 661                 ret = 0;
 662             } else {
 663                 ret = ec_gen_set_group(gctx, nid);
 664             }
 665         }
 666         return ret;
 667     }
 668     return 1;
 669 }
 670
 671 static const OSSL_PARAM *ec_gen_settable_params(void *provctx)
 672 {
 673     static OSSL_PARAM settable[] = {
 674         OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_NAME, NULL, 0),
 675         OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 676         OSSL_PARAM_END
 677     };
 678
 679     return settable;
 680 }
 681
 682 static int ec_gen_assign_group(EC_KEY *ec, EC_GROUP *group)
 683 {
 684     if (group == NULL) {
 685         ERR_raise(ERR_LIB_PROV, PROV_R_NO_PARAMETERS_SET);
 686         return 0;
 687     }
 688     return EC_KEY_set_group(ec, group) > 0;
 689 }
 690
 691 /*
 692  * The callback arguments (osslcb & cbarg) are not used by EC_KEY generation
 693  */
 694 static void *ec_gen(void *genctx, OSSL_CALLBACK *osslcb, void *cbarg)
 695 {
 696     struct ec_gen_ctx *gctx = genctx;
 697     EC_KEY *ec = NULL;
 698     int ret = 1;                 /* Start optimistically */
 699
 700     if (gctx == NULL
 701         || (ec = EC_KEY_new_ex(gctx->libctx)) == NULL)
 702         return NULL;
 703
 704     /* We must always assign a group, no matter what */
 705     ret = ec_gen_assign_group(ec, gctx->gen_group);
 706     /* Whether you want it or not, you get a keypair, not just one half */
 707     if ((gctx->selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0)
 708         ret = ret && EC_KEY_generate_key(ec);
 709
 710     if (gctx->ecdh_mode != -1)
 711         ret = ret && ec_set_ecdh_cofactor_mode(ec, gctx->ecdh_mode);
 712
 713     if (ret)
 714         return ec;
 715
 716     /* Something went wrong, throw the key away */
 717     EC_KEY_free(ec);
 718     return NULL;
 719 }
 720
 721 static void ec_gen_cleanup(void *genctx)
 722 {
 723     struct ec_gen_ctx *gctx = genctx;
 724
 725     if (gctx == NULL)
 726         return;
 727
 728     EC_GROUP_free(gctx->gen_group);
 729     OPENSSL_free(gctx);
 730 }
 731
 732 const OSSL_DISPATCH ec_keymgmt_functions[] = {
 733     { OSSL_FUNC_KEYMGMT_NEW, (void (*)(void))ec_newdata },
 734     { OSSL_FUNC_KEYMGMT_GEN_INIT, (void (*)(void))ec_gen_init },
 735     { OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE,
 736       (void (*)(void))ec_gen_set_template },
 737     { OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS, (void (*)(void))ec_gen_set_params },
 738     { OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS,
 739       (void (*)(void))ec_gen_settable_params },
 740     { OSSL_FUNC_KEYMGMT_GEN, (void (*)(void))ec_gen },
 741     { OSSL_FUNC_KEYMGMT_GEN_CLEANUP, (void (*)(void))ec_gen_cleanup },
 742     { OSSL_FUNC_KEYMGMT_FREE, (void (*)(void))ec_freedata },
 743     { OSSL_FUNC_KEYMGMT_GET_PARAMS, (void (*) (void))ec_get_params },
 744     { OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS, (void (*) (void))ec_gettable_params },
 745     { OSSL_FUNC_KEYMGMT_SET_PARAMS, (void (*) (void))ec_set_params },
 746     { OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS, (void (*) (void))ec_settable_params },
 747     { OSSL_FUNC_KEYMGMT_HAS, (void (*)(void))ec_has },
 748     { OSSL_FUNC_KEYMGMT_MATCH, (void (*)(void))ec_match },
 749     { OSSL_FUNC_KEYMGMT_VALIDATE, (void (*)(void))ec_validate },
 750     { OSSL_FUNC_KEYMGMT_IMPORT, (void (*)(void))ec_import },
 751     { OSSL_FUNC_KEYMGMT_IMPORT_TYPES, (void (*)(void))ec_import_types },
 752     { OSSL_FUNC_KEYMGMT_EXPORT, (void (*)(void))ec_export },
 753     { OSSL_FUNC_KEYMGMT_EXPORT_TYPES, (void (*)(void))ec_export_types },
 754     { OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME,
 755       (void (*)(void))ec_query_operation_name },
 756     { 0, NULL }
 757 };