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 "e_os.h" /* strcasecmp */
  17 #include <string.h>
  18 #include <openssl/core_dispatch.h>
  19 #include <openssl/core_names.h>
  20 #include <openssl/bn.h>
  21 #include <openssl/err.h>
  22 #include <openssl/objects.h>
  23 #include "crypto/bn.h"
  24 #include "crypto/ec.h"
  25 #include "prov/implementations.h"
  26 #include "prov/providercommon.h"
  27 #include "prov/providercommonerr.h"
  28 #include "prov/provider_ctx.h"
  29 #include "internal/param_build_set.h"
  30
  31 static OSSL_FUNC_keymgmt_new_fn ec_newdata;
  32 static OSSL_FUNC_keymgmt_gen_init_fn ec_gen_init;
  33 static OSSL_FUNC_keymgmt_gen_set_template_fn ec_gen_set_template;
  34 static OSSL_FUNC_keymgmt_gen_set_params_fn ec_gen_set_params;
  35 static OSSL_FUNC_keymgmt_gen_settable_params_fn ec_gen_settable_params;
  36 static OSSL_FUNC_keymgmt_gen_fn ec_gen;
  37 static OSSL_FUNC_keymgmt_gen_cleanup_fn ec_gen_cleanup;
  38 static OSSL_FUNC_keymgmt_load_fn ec_load;
  39 static OSSL_FUNC_keymgmt_free_fn ec_freedata;
  40 static OSSL_FUNC_keymgmt_get_params_fn ec_get_params;
  41 static OSSL_FUNC_keymgmt_gettable_params_fn ec_gettable_params;
  42 static OSSL_FUNC_keymgmt_set_params_fn ec_set_params;
  43 static OSSL_FUNC_keymgmt_settable_params_fn ec_settable_params;
  44 static OSSL_FUNC_keymgmt_has_fn ec_has;
  45 static OSSL_FUNC_keymgmt_match_fn ec_match;
  46 static OSSL_FUNC_keymgmt_validate_fn ec_validate;
  47 static OSSL_FUNC_keymgmt_import_fn ec_import;
  48 static OSSL_FUNC_keymgmt_import_types_fn ec_import_types;
  49 static OSSL_FUNC_keymgmt_export_fn ec_export;
  50 static OSSL_FUNC_keymgmt_export_types_fn ec_export_types;
  51 static OSSL_FUNC_keymgmt_query_operation_name_fn ec_query_operation_name;
  52
  53 #define EC_DEFAULT_MD "SHA256"
  54 #define EC_POSSIBLE_SELECTIONS                                                 \
  55     (OSSL_KEYMGMT_SELECT_KEYPAIR | OSSL_KEYMGMT_SELECT_ALL_PARAMETERS)
  56
  57 static
  58 const char *ec_query_operation_name(int operation_id)
  59 {
  60     switch (operation_id) {
  61     case OSSL_OP_KEYEXCH:
  62         return "ECDH";
  63     case OSSL_OP_SIGNATURE:
  64         return "ECDSA";
  65     }
  66     return NULL;
  67 }
  68
  69 /*
  70  * Callers of key_to_params MUST make sure that domparams_to_params is also
  71  * called!
  72  *
  73  * This function only exports the bare keypair, domain parameters and other
  74  * parameters are exported separately.
  75  */
  76 static ossl_inline
  77 int key_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl,
  78                   OSSL_PARAM params[], int include_private,
  79                   unsigned char **pub_key)
  80 {
  81     BIGNUM *x = NULL, *y = NULL;
  82     const BIGNUM *priv_key = NULL;
  83     const EC_POINT *pub_point = NULL;
  84     const EC_GROUP *ecg = NULL;
  85     size_t pub_key_len = 0;
  86     int ret = 0;
  87     BN_CTX *bnctx = NULL;
  88
  89     if (eckey == NULL
  90         || (ecg = EC_KEY_get0_group(eckey)) == NULL)
  91         return 0;
  92
  93     priv_key = EC_KEY_get0_private_key(eckey);
  94     pub_point = EC_KEY_get0_public_key(eckey);
  95
  96     if (pub_point != NULL) {
  97         OSSL_PARAM *p = NULL, *px = NULL, *py = NULL;
  98         /*
  99          * EC_POINT_point2buf() can generate random numbers in some
 100          * implementations so we need to ensure we use the correct libctx.
 101          */
 102         bnctx = BN_CTX_new_ex(ec_key_get_libctx(eckey));
 103         if (bnctx == NULL)
 104             goto err;
 105
 106
 107         /* If we are doing a get then check first before decoding the point */
 108         if (tmpl == NULL) {
 109             p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_PUB_KEY);
 110             px = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_EC_PUB_X);
 111             py = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_EC_PUB_Y);
 112         }
 113
 114         if (p != NULL || tmpl != NULL) {
 115             /* convert pub_point to a octet string according to the SECG standard */
 116             if ((pub_key_len = EC_POINT_point2buf(ecg, pub_point,
 117                                                   POINT_CONVERSION_COMPRESSED,
 118                                                   pub_key, bnctx)) == 0
 119                 || !ossl_param_build_set_octet_string(tmpl, p,
 120                                                       OSSL_PKEY_PARAM_PUB_KEY,
 121                                                       *pub_key, pub_key_len))
 122                 goto err;
 123         }
 124         if (px != NULL || py != NULL) {
 125             if (px != NULL)
 126                 x = BN_CTX_get(bnctx);
 127             if (py != NULL)
 128                 y = BN_CTX_get(bnctx);
 129
 130             if (!EC_POINT_get_affine_coordinates(ecg, pub_point, x, y, bnctx))
 131                 goto err;
 132             if (px != NULL
 133                 && !ossl_param_build_set_bn(tmpl, px,
 134                                             OSSL_PKEY_PARAM_EC_PUB_X, x))
 135                 goto err;
 136             if (py != NULL
 137                 && !ossl_param_build_set_bn(tmpl, py,
 138                                             OSSL_PKEY_PARAM_EC_PUB_Y, y))
 139                 goto err;
 140         }
 141     }
 142
 143     if (priv_key != NULL && include_private) {
 144         size_t sz;
 145         int ecbits;
 146
 147         /*
 148          * Key import/export should never leak the bit length of the secret
 149          * scalar in the key.
 150          *
 151          * For this reason, on export we use padded BIGNUMs with fixed length.
 152          *
 153          * When importing we also should make sure that, even if short lived,
 154          * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
 155          * soon as possible, so that any processing of this BIGNUM might opt for
 156          * constant time implementations in the backend.
 157          *
 158          * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
 159          * to preallocate the BIGNUM internal buffer to a fixed public size big
 160          * enough that operations performed during the processing never trigger
 161          * a realloc which would leak the size of the scalar through memory
 162          * accesses.
 163          *
 164          * Fixed Length
 165          * ------------
 166          *
 167          * The order of the large prime subgroup of the curve is our choice for
 168          * a fixed public size, as that is generally the upper bound for
 169          * generating a private key in EC cryptosystems and should fit all valid
 170          * secret scalars.
 171          *
 172          * For padding on export we just use the bit length of the order
 173          * converted to bytes (rounding up).
 174          *
 175          * For preallocating the BIGNUM storage we look at the number of "words"
 176          * required for the internal representation of the order, and we
 177          * preallocate 2 extra "words" in case any of the subsequent processing
 178          * might temporarily overflow the order length.
 179          */
 180         ecbits = EC_GROUP_order_bits(ecg);
 181         if (ecbits <= 0)
 182             goto err;
 183         sz = (ecbits + 7 ) / 8;
 184
 185         if (!ossl_param_build_set_bn_pad(tmpl, params,
 186                                          OSSL_PKEY_PARAM_PRIV_KEY,
 187                                          priv_key, sz))
 188             goto err;
 189     }
 190     ret = 1;
 191  err:
 192     BN_CTX_free(bnctx);
 193     return ret;
 194 }
 195
 196 static ossl_inline
 197 int otherparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl,
 198                           OSSL_PARAM params[])
 199 {
 200     int ecdh_cofactor_mode = 0;
 201
 202     if (ec == NULL)
 203         return 0;
 204
 205     ecdh_cofactor_mode =
 206         (EC_KEY_get_flags(ec) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 207     return ossl_param_build_set_int(tmpl, params,
 208                                     OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
 209                                     ecdh_cofactor_mode);
 210 }
 211
 212 static
 213 void *ec_newdata(void *provctx)
 214 {
 215     return EC_KEY_new_with_libctx(PROV_LIBRARY_CONTEXT_OF(provctx), NULL);
 216 }
 217
 218 static
 219 void ec_freedata(void *keydata)
 220 {
 221     EC_KEY_free(keydata);
 222 }
 223
 224 static
 225 int ec_has(void *keydata, int selection)
 226 {
 227     EC_KEY *ec = keydata;
 228     int ok = 0;
 229
 230     if (ec != NULL) {
 231         if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 232             ok = 1;
 233
 234         if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 235             ok = ok && (EC_KEY_get0_public_key(ec) != NULL);
 236         if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 237             ok = ok && (EC_KEY_get0_private_key(ec) != NULL);
 238         if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 239             ok = ok && (EC_KEY_get0_group(ec) != NULL);
 240         /*
 241          * We consider OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS to always be
 242          * available, so no extra check is needed other than the previous one
 243          * against EC_POSSIBLE_SELECTIONS.
 244          */
 245     }
 246     return ok;
 247 }
 248
 249 static int ec_match(const void *keydata1, const void *keydata2, int selection)
 250 {
 251     const EC_KEY *ec1 = keydata1;
 252     const EC_KEY *ec2 = keydata2;
 253     const EC_GROUP *group_a = EC_KEY_get0_group(ec1);
 254     const EC_GROUP *group_b = EC_KEY_get0_group(ec2);
 255     BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(ec1));
 256     int ok = 1;
 257
 258     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 259         ok = ok && group_a != NULL && group_b != NULL
 260             && EC_GROUP_cmp(group_a, group_b, ctx) == 0;
 261     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {
 262         const BIGNUM *pa = EC_KEY_get0_private_key(ec1);
 263         const BIGNUM *pb = EC_KEY_get0_private_key(ec2);
 264
 265         ok = ok && BN_cmp(pa, pb) == 0;
 266     }
 267     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0) {
 268         const EC_POINT *pa = EC_KEY_get0_public_key(ec1);
 269         const EC_POINT *pb = EC_KEY_get0_public_key(ec2);
 270
 271         ok = ok && EC_POINT_cmp(group_b, pa, pb, ctx) == 0;
 272     }
 273     BN_CTX_free(ctx);
 274     return ok;
 275 }
 276
 277 static
 278 int ec_import(void *keydata, int selection, const OSSL_PARAM params[])
 279 {
 280     EC_KEY *ec = keydata;
 281     int ok = 1;
 282
 283     if (ec == NULL)
 284         return 0;
 285
 286     /*
 287      * In this implementation, we can export/import only keydata in the
 288      * following combinations:
 289      *   - domain parameters (+optional other params)
 290      *   - public key with associated domain parameters (+optional other params)
 291      *   - private key with associated public key and domain parameters
 292      *         (+optional other params)
 293      *
 294      * This means:
 295      *   - domain parameters must always be requested
 296      *   - private key must be requested alongside public key
 297      *   - other parameters are always optional
 298      */
 299     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 300         return 0;
 301     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 302             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 303         return 0;
 304
 305     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 306         ok = ok && ec_group_fromdata(ec, params);
 307     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 308         int include_private =
 309             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 310
 311         ok = ok && ec_key_fromdata(ec, params, include_private);
 312     }
 313     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 314         ok = ok && ec_key_otherparams_fromdata(ec, params);
 315
 316     return ok;
 317 }
 318
 319 static
 320 int ec_export(void *keydata, int selection, OSSL_CALLBACK *param_cb,
 321               void *cbarg)
 322 {
 323     EC_KEY *ec = keydata;
 324     OSSL_PARAM_BLD *tmpl;
 325     OSSL_PARAM *params = NULL;
 326     unsigned char *pub_key = NULL, *genbuf = NULL;
 327     BN_CTX *bnctx = NULL;
 328     int ok = 1;
 329
 330     if (ec == NULL)
 331         return 0;
 332
 333     /*
 334      * In this implementation, we can export/import only keydata in the
 335      * following combinations:
 336      *   - domain parameters (+optional other params)
 337      *   - public key with associated domain parameters (+optional other params)
 338      *   - private key with associated public key and domain parameters
 339      *         (+optional other params)
 340      *
 341      * This means:
 342      *   - domain parameters must always be requested
 343      *   - private key must be requested alongside public key
 344      *   - other parameters are always optional
 345      */
 346     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
 347         return 0;
 348     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
 349             && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
 350         return 0;
 351     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
 352             && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
 353         return 0;
 354
 355     tmpl = OSSL_PARAM_BLD_new();
 356     if (tmpl == NULL)
 357         return 0;
 358
 359     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0) {
 360         bnctx = BN_CTX_new_ex(ec_key_get_libctx(ec));
 361         BN_CTX_start(bnctx);
 362         ok = ok && (bnctx != NULL);
 363         ok = ok && ec_group_todata(EC_KEY_get0_group(ec), tmpl, NULL,
 364                                    ec_key_get_libctx(ec), ec_key_get0_propq(ec),
 365                                    bnctx, &genbuf);
 366     }
 367
 368     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
 369         int include_private =
 370             selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
 371
 372         ok = ok && key_to_params(ec, tmpl, NULL, include_private, &pub_key);
 373     }
 374     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 375         ok = ok && otherparams_to_params(ec, tmpl, NULL);
 376
 377     if (ok && (params = OSSL_PARAM_BLD_to_param(tmpl)) != NULL)
 378         ok = param_cb(params, cbarg);
 379
 380     OSSL_PARAM_BLD_free_params(params);
 381     OSSL_PARAM_BLD_free(tmpl);
 382     OPENSSL_free(pub_key);
 383     OPENSSL_free(genbuf);
 384     BN_CTX_end(bnctx);
 385     BN_CTX_free(bnctx);
 386     return ok;
 387 }
 388
 389 /* IMEXPORT = IMPORT + EXPORT */
 390
 391 # define EC_IMEXPORTABLE_DOM_PARAMETERS                                        \
 392     OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME, NULL, 0),               \
 393     OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_ENCODING, NULL, 0),              \
 394     OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_FIELD_TYPE, NULL, 0),            \
 395     OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_P, NULL, 0),                              \
 396     OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_A, NULL, 0),                              \
 397     OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_B, NULL, 0),                              \
 398     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_GENERATOR, NULL, 0),            \
 399     OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_ORDER, NULL, 0),                          \
 400     OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_COFACTOR, NULL, 0),                       \
 401     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_SEED, NULL, 0)
 402
 403 # define EC_IMEXPORTABLE_PUBLIC_KEY                                            \
 404     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_PUB_KEY, NULL, 0)
 405 # define EC_IMEXPORTABLE_PRIVATE_KEY                                           \
 406     OSSL_PARAM_BN(OSSL_PKEY_PARAM_PRIV_KEY, NULL, 0)
 407 # define EC_IMEXPORTABLE_OTHER_PARAMETERS                                      \
 408     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL)
 409
 410 /*
 411  * Include all the possible combinations of OSSL_PARAM arrays for
 412  * ec_imexport_types().
 413  *
 414  * They are in a separate file as it is ~100 lines of unreadable and
 415  * uninteresting machine generated stuff.
 416  *
 417  * TODO(3.0): the generated list looks quite ugly, as to cover all possible
 418  * combinations of the bits in `selection`, it also includes combinations that
 419  * are not really useful: we might want to consider alternatives to this
 420  * solution.
 421  */
 422 #include "ec_kmgmt_imexport.inc"
 423
 424 static ossl_inline
 425 const OSSL_PARAM *ec_imexport_types(int selection)
 426 {
 427     int type_select = 0;
 428
 429     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 430         type_select += 1;
 431     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 432         type_select += 2;
 433     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 434         type_select += 4;
 435     if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
 436         type_select += 8;
 437     return ec_types[type_select];
 438 }
 439
 440 static
 441 const OSSL_PARAM *ec_import_types(int selection)
 442 {
 443     return ec_imexport_types(selection);
 444 }
 445
 446 static
 447 const OSSL_PARAM *ec_export_types(int selection)
 448 {
 449     return ec_imexport_types(selection);
 450 }
 451
 452 static int ec_get_ecm_params(const EC_GROUP *group, OSSL_PARAM params[])
 453 {
 454 #ifdef OPENSSL_NO_EC2M
 455     return 1;
 456 #else
 457     int ret = 0, m;
 458     unsigned int k1 = 0, k2 = 0, k3 = 0;
 459     int basis_nid;
 460     const char *basis_name = NULL;
 461     int fid = EC_GROUP_get_field_type(group);
 462
 463     if (fid != NID_X9_62_characteristic_two_field)
 464         return 1;
 465
 466     basis_nid = EC_GROUP_get_basis_type(group);
 467     if (basis_nid == NID_X9_62_tpBasis)
 468         basis_name = SN_X9_62_tpBasis;
 469     else if (basis_nid == NID_X9_62_ppBasis)
 470         basis_name = SN_X9_62_ppBasis;
 471     else
 472         goto err;
 473
 474     m = EC_GROUP_get_degree(group);
 475     if (!ossl_param_build_set_int(NULL, params, OSSL_PKEY_PARAM_EC_CHAR2_M, m)
 476         || !ossl_param_build_set_utf8_string(NULL, params,
 477                                              OSSL_PKEY_PARAM_EC_CHAR2_TYPE,
 478                                              basis_name))
 479         goto err;
 480
 481     if (basis_nid == NID_X9_62_tpBasis) {
 482         if (!EC_GROUP_get_trinomial_basis(group, &k1)
 483             || !ossl_param_build_set_int(NULL, params,
 484                                          OSSL_PKEY_PARAM_EC_CHAR2_TP_BASIS,
 485                                          (int)k1))
 486             goto err;
 487     } else {
 488         if (!EC_GROUP_get_pentanomial_basis(group, &k1, &k2, &k3)
 489             || !ossl_param_build_set_int(NULL, params,
 490                                          OSSL_PKEY_PARAM_EC_CHAR2_PP_K1, (int)k1)
 491             || !ossl_param_build_set_int(NULL, params,
 492                                          OSSL_PKEY_PARAM_EC_CHAR2_PP_K2, (int)k2)
 493             || !ossl_param_build_set_int(NULL, params,
 494                                          OSSL_PKEY_PARAM_EC_CHAR2_PP_K3, (int)k3))
 495             goto err;
 496     }
 497     ret = 1;
 498 err:
 499     return ret;
 500 #endif /* OPENSSL_NO_EC2M */
 501 }
 502
 503 static
 504 int ec_get_params(void *key, OSSL_PARAM params[])
 505 {
 506     int ret = 0;
 507     EC_KEY *eck = key;
 508     const EC_GROUP *ecg = NULL;
 509     OSSL_PARAM *p;
 510     unsigned char *pub_key = NULL, *genbuf = NULL;
 511     OPENSSL_CTX *libctx;
 512     const char *propq;
 513     BN_CTX *bnctx = NULL;
 514
 515     ecg = EC_KEY_get0_group(eck);
 516     if (ecg == NULL)
 517         return 0;
 518
 519     libctx = ec_key_get_libctx(eck);
 520     propq = ec_key_get0_propq(eck);
 521
 522     bnctx = BN_CTX_new_ex(libctx);
 523     if (bnctx == NULL)
 524         return 0;
 525     BN_CTX_start(bnctx);
 526
 527     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_MAX_SIZE)) != NULL
 528         && !OSSL_PARAM_set_int(p, ECDSA_size(eck)))
 529         return 0;
 530     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_BITS)) != NULL
 531         && !OSSL_PARAM_set_int(p, EC_GROUP_order_bits(ecg)))
 532         return 0;
 533     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_SECURITY_BITS)) != NULL) {
 534         int ecbits, sec_bits;
 535
 536         ecbits = EC_GROUP_order_bits(ecg);
 537
 538         /*
 539          * The following estimates are based on the values published
 540          * in Table 2 of "NIST Special Publication 800-57 Part 1 Revision 4"
 541          * at http://dx.doi.org/10.6028/NIST.SP.800-57pt1r4 .
 542          *
 543          * Note that the above reference explicitly categorizes algorithms in a
 544          * discrete set of values {80, 112, 128, 192, 256}, and that it is
 545          * relevant only for NIST approved Elliptic Curves, while OpenSSL
 546          * applies the same logic also to other curves.
 547          *
 548          * Classifications produced by other standardazing bodies might differ,
 549          * so the results provided for "bits of security" by this provider are
 550          * to be considered merely indicative, and it is the users'
 551          * responsibility to compare these values against the normative
 552          * references that may be relevant for their intent and purposes.
 553          */
 554         if (ecbits >= 512)
 555             sec_bits = 256;
 556         else if (ecbits >= 384)
 557             sec_bits = 192;
 558         else if (ecbits >= 256)
 559             sec_bits = 128;
 560         else if (ecbits >= 224)
 561             sec_bits = 112;
 562         else if (ecbits >= 160)
 563             sec_bits = 80;
 564         else
 565             sec_bits = ecbits / 2;
 566
 567         if (!OSSL_PARAM_set_int(p, sec_bits))
 568             return 0;
 569     }
 570
 571     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_DEFAULT_DIGEST)) != NULL
 572         && !OSSL_PARAM_set_utf8_string(p, EC_DEFAULT_MD))
 573         return 0;
 574
 575     p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
 576     if (p != NULL) {
 577         int ecdh_cofactor_mode = 0;
 578
 579         ecdh_cofactor_mode =
 580             (EC_KEY_get_flags(eck) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
 581
 582         if (!OSSL_PARAM_set_int(p, ecdh_cofactor_mode))
 583             return 0;
 584     }
 585     if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_TLS_ENCODED_PT)) != NULL) {
 586         p->return_size = EC_POINT_point2oct(EC_KEY_get0_group(key),
 587                                             EC_KEY_get0_public_key(key),
 588                                             POINT_CONVERSION_UNCOMPRESSED,
 589                                             p->data, p->return_size, bnctx);
 590         if (p->return_size == 0)
 591             goto err;
 592     }
 593
 594     ret = ec_get_ecm_params(ecg, params)
 595           && ec_group_todata(ecg, NULL, params, libctx, propq, bnctx, &genbuf)
 596           && key_to_params(eck, NULL, params, 1, &pub_key)
 597           && otherparams_to_params(eck, NULL, params);
 598 err:
 599     OPENSSL_free(genbuf);
 600     OPENSSL_free(pub_key);
 601     BN_CTX_end(bnctx);
 602     BN_CTX_free(bnctx);
 603     return ret;
 604 }
 605
 606 #ifndef OPENSSL_NO_EC2M
 607 # define EC2M_GETTABLE_DOM_PARAMS                                              \
 608         OSSL_PARAM_int(OSSL_PKEY_PARAM_EC_CHAR2_M, NULL),                      \
 609         OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_CHAR2_TYPE, NULL, 0),        \
 610         OSSL_PARAM_int(OSSL_PKEY_PARAM_EC_CHAR2_TP_BASIS, NULL),               \
 611         OSSL_PARAM_int(OSSL_PKEY_PARAM_EC_CHAR2_PP_K1, NULL),                  \
 612         OSSL_PARAM_int(OSSL_PKEY_PARAM_EC_CHAR2_PP_K2, NULL),                  \
 613         OSSL_PARAM_int(OSSL_PKEY_PARAM_EC_CHAR2_PP_K3, NULL),
 614 #else
 615 # define EC2M_GETTABLE_DOM_PARAMS
 616 #endif
 617
 618 static const OSSL_PARAM ec_known_gettable_params[] = {
 619     OSSL_PARAM_int(OSSL_PKEY_PARAM_BITS, NULL),
 620     OSSL_PARAM_int(OSSL_PKEY_PARAM_SECURITY_BITS, NULL),
 621     OSSL_PARAM_int(OSSL_PKEY_PARAM_MAX_SIZE, NULL),
 622     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_TLS_ENCODED_PT, NULL, 0),
 623     EC_IMEXPORTABLE_DOM_PARAMETERS,
 624     EC2M_GETTABLE_DOM_PARAMS
 625     EC_IMEXPORTABLE_PUBLIC_KEY,
 626     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_PUB_X, NULL, 0),
 627     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_PUB_Y, NULL, 0),
 628     EC_IMEXPORTABLE_PRIVATE_KEY,
 629     EC_IMEXPORTABLE_OTHER_PARAMETERS,
 630     OSSL_PARAM_END
 631 };
 632
 633 static
 634 const OSSL_PARAM *ec_gettable_params(void *provctx)
 635 {
 636     return ec_known_gettable_params;
 637 }
 638
 639 static const OSSL_PARAM ec_known_settable_params[] = {
 640     OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 641     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_TLS_ENCODED_PT, NULL, 0),
 642     OSSL_PARAM_END
 643 };
 644
 645 static
 646 const OSSL_PARAM *ec_settable_params(void *provctx)
 647 {
 648     return ec_known_settable_params;
 649 }
 650
 651 static
 652 int ec_set_params(void *key, const OSSL_PARAM params[])
 653 {
 654     EC_KEY *eck = key;
 655     const OSSL_PARAM *p;
 656
 657     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_TLS_ENCODED_PT);
 658     if (p != NULL) {
 659         BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(key));
 660         int ret = 1;
 661
 662         if (ctx == NULL
 663                 || p->data_type != OSSL_PARAM_OCTET_STRING
 664                 || !EC_KEY_oct2key(key, p->data, p->data_size, ctx))
 665             ret = 0;
 666         BN_CTX_free(ctx);
 667         if (!ret)
 668             return 0;
 669     }
 670
 671     return ec_key_otherparams_fromdata(eck, params);
 672 }
 673
 674 static
 675 int ec_validate(void *keydata, int selection)
 676 {
 677     EC_KEY *eck = keydata;
 678     int ok = 0;
 679     BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(eck));
 680
 681     if (ctx == NULL)
 682         return 0;
 683
 684     if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
 685         ok = 1;
 686
 687     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
 688         ok = ok && EC_GROUP_check(EC_KEY_get0_group(eck), ctx);
 689
 690     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
 691         ok = ok && ec_key_public_check(eck, ctx);
 692
 693     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
 694         ok = ok && ec_key_private_check(eck);
 695
 696     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == OSSL_KEYMGMT_SELECT_KEYPAIR)
 697         ok = ok && ec_key_pairwise_check(eck, ctx);
 698
 699     BN_CTX_free(ctx);
 700     return ok;
 701 }
 702
 703 struct ec_gen_ctx {
 704     OPENSSL_CTX *libctx;
 705     char *group_name;
 706     char *encoding;
 707     char *field_type;
 708     BIGNUM *p, *a, *b, *order, *cofactor;
 709     unsigned char *gen, *seed;
 710     size_t gen_len, seed_len;
 711     int selection;
 712     int ecdh_mode;
 713     EC_GROUP *gen_group;
 714 };
 715
 716 static void *ec_gen_init(void *provctx, int selection)
 717 {
 718     OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
 719     struct ec_gen_ctx *gctx = NULL;
 720
 721     if ((selection & (EC_POSSIBLE_SELECTIONS)) == 0)
 722         return NULL;
 723
 724     if ((gctx = OPENSSL_zalloc(sizeof(*gctx))) != NULL) {
 725         gctx->libctx = libctx;
 726         gctx->selection = selection;
 727         gctx->ecdh_mode = 0;
 728     }
 729     return gctx;
 730 }
 731
 732 static int ec_gen_set_group(void *genctx, const EC_GROUP *src)
 733 {
 734     struct ec_gen_ctx *gctx = genctx;
 735     EC_GROUP *group;
 736
 737     group = EC_GROUP_dup(src);
 738     if (group == NULL) {
 739         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
 740         return 0;
 741     }
 742     EC_GROUP_free(gctx->gen_group);
 743     gctx->gen_group = group;
 744     return 1;
 745 }
 746
 747 static int ec_gen_set_template(void *genctx, void *templ)
 748 {
 749     struct ec_gen_ctx *gctx = genctx;
 750     EC_KEY *ec = templ;
 751     const EC_GROUP *ec_group;
 752
 753     if (gctx == NULL || ec == NULL)
 754         return 0;
 755     if ((ec_group = EC_KEY_get0_group(ec)) == NULL)
 756         return 0;
 757     return ec_gen_set_group(gctx, ec_group);
 758 }
 759
 760 #define COPY_INT_PARAM(params, key, val)                                       \
 761 p = OSSL_PARAM_locate_const(params, key);                                      \
 762 if (p != NULL && !OSSL_PARAM_get_int(p, &val))                                 \
 763     goto err;
 764
 765 #define COPY_UTF8_PARAM(params, key, val)                                      \
 766 p = OSSL_PARAM_locate_const(params, key);                                      \
 767 if (p != NULL) {                                                               \
 768     if (p->data_type != OSSL_PARAM_UTF8_STRING)                                \
 769         goto err;                                                              \
 770     OPENSSL_free(val);                                                         \
 771     val = OPENSSL_strdup(p->data);                                             \
 772     if (val == NULL)                                                           \
 773         goto err;                                                              \
 774 }
 775
 776 #define COPY_OCTET_PARAM(params, key, val, len)                                \
 777 p = OSSL_PARAM_locate_const(params, key);                                      \
 778 if (p != NULL) {                                                               \
 779     if (p->data_type != OSSL_PARAM_OCTET_STRING)                               \
 780         goto err;                                                              \
 781     OPENSSL_free(val);                                                         \
 782     len = p->data_size;                                                        \
 783     val = OPENSSL_memdup(p->data, p->data_size);                               \
 784     if (val == NULL)                                                           \
 785         goto err;                                                              \
 786 }
 787
 788 #define COPY_BN_PARAM(params, key, bn)                                         \
 789 p = OSSL_PARAM_locate_const(params, key);                                      \
 790 if (p != NULL) {                                                               \
 791     if (bn == NULL)                                                            \
 792         bn = BN_new();                                                         \
 793     if (bn == NULL || !OSSL_PARAM_get_BN(p, &bn))                              \
 794         goto err;                                                              \
 795 }
 796
 797 static int ec_gen_set_params(void *genctx, const OSSL_PARAM params[])
 798 {
 799     int ret = 0;
 800     struct ec_gen_ctx *gctx = genctx;
 801     const OSSL_PARAM *p;
 802     EC_GROUP *group = NULL;
 803
 804     COPY_INT_PARAM(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, gctx->ecdh_mode);
 805
 806     COPY_UTF8_PARAM(params, OSSL_PKEY_PARAM_GROUP_NAME, gctx->group_name);
 807     COPY_UTF8_PARAM(params, OSSL_PKEY_PARAM_EC_FIELD_TYPE, gctx->field_type);
 808     COPY_UTF8_PARAM(params, OSSL_PKEY_PARAM_EC_ENCODING, gctx->encoding);
 809
 810     COPY_BN_PARAM(params, OSSL_PKEY_PARAM_EC_P, gctx->p);
 811     COPY_BN_PARAM(params, OSSL_PKEY_PARAM_EC_A, gctx->a);
 812     COPY_BN_PARAM(params, OSSL_PKEY_PARAM_EC_B, gctx->b);
 813     COPY_BN_PARAM(params, OSSL_PKEY_PARAM_EC_ORDER, gctx->order);
 814     COPY_BN_PARAM(params, OSSL_PKEY_PARAM_EC_COFACTOR, gctx->cofactor);
 815
 816     COPY_OCTET_PARAM(params, OSSL_PKEY_PARAM_EC_SEED, gctx->seed, gctx->seed_len);
 817     COPY_OCTET_PARAM(params, OSSL_PKEY_PARAM_EC_GENERATOR, gctx->gen,
 818                      gctx->gen_len);
 819
 820     ret = 1;
 821 err:
 822     EC_GROUP_free(group);
 823     return ret;
 824 }
 825
 826 static int ec_gen_set_group_from_params(struct ec_gen_ctx *gctx)
 827 {
 828     int ret = 0;
 829     OSSL_PARAM_BLD *bld;
 830     OSSL_PARAM *params = NULL;
 831     EC_GROUP *group = NULL;
 832
 833     bld = OSSL_PARAM_BLD_new();
 834     if (bld == NULL)
 835         return 0;
 836
 837     if (gctx->encoding != NULL
 838         && !OSSL_PARAM_BLD_push_utf8_string(bld, OSSL_PKEY_PARAM_EC_ENCODING,
 839                                             gctx->encoding, 0))
 840         goto err;
 841
 842     if (gctx->group_name != NULL) {
 843         if (!OSSL_PARAM_BLD_push_utf8_string(bld, OSSL_PKEY_PARAM_GROUP_NAME,
 844                                              gctx->group_name, 0))
 845             goto err;
 846         /* Ignore any other parameters if there is a group name */
 847         goto build;
 848     } else if (gctx->field_type != NULL) {
 849         if (!OSSL_PARAM_BLD_push_utf8_string(bld, OSSL_PKEY_PARAM_EC_FIELD_TYPE,
 850                                              gctx->field_type, 0))
 851             goto err;
 852     } else {
 853         goto err;
 854     }
 855     if (gctx->p == NULL
 856         || gctx->a == NULL
 857         || gctx->b == NULL
 858         || gctx->order == NULL
 859         || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_EC_P, gctx->p)
 860         || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_EC_A, gctx->a)
 861         || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_EC_B, gctx->b)
 862         || !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_EC_ORDER, gctx->order))
 863         goto err;
 864
 865     if (gctx->cofactor != NULL
 866         && !OSSL_PARAM_BLD_push_BN(bld, OSSL_PKEY_PARAM_EC_COFACTOR,
 867                                    gctx->cofactor))
 868         goto err;
 869
 870     if (gctx->seed != NULL
 871         && !OSSL_PARAM_BLD_push_octet_string(bld, OSSL_PKEY_PARAM_EC_SEED,
 872                                              gctx->seed, gctx->seed_len))
 873         goto err;
 874
 875     if (gctx->gen == NULL
 876         || !OSSL_PARAM_BLD_push_octet_string(bld, OSSL_PKEY_PARAM_EC_GENERATOR,
 877                                              gctx->gen, gctx->gen_len))
 878         goto err;
 879 build:
 880     params = OSSL_PARAM_BLD_to_param(bld);
 881     if (params == NULL)
 882         goto err;
 883     group = EC_GROUP_new_from_params(params, gctx->libctx, NULL);
 884     if (group == NULL)
 885         goto err;
 886
 887     EC_GROUP_free(gctx->gen_group);
 888     gctx->gen_group = group;
 889
 890     ret = 1;
 891 err:
 892     OSSL_PARAM_BLD_free_params(params);
 893     OSSL_PARAM_BLD_free(bld);
 894     return ret;
 895 }
 896
 897 static const OSSL_PARAM *ec_gen_settable_params(void *provctx)
 898 {
 899     static OSSL_PARAM settable[] = {
 900         OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME, NULL, 0),
 901         OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
 902         OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_ENCODING, NULL, 0),
 903         OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_EC_FIELD_TYPE, NULL, 0),
 904         OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_P, NULL, 0),
 905         OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_A, NULL, 0),
 906         OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_B, NULL, 0),
 907         OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_GENERATOR, NULL, 0),
 908         OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_ORDER, NULL, 0),
 909         OSSL_PARAM_BN(OSSL_PKEY_PARAM_EC_COFACTOR, NULL, 0),
 910         OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_SEED, NULL, 0),
 911         OSSL_PARAM_END
 912     };
 913
 914     return settable;
 915 }
 916
 917 static int ec_gen_assign_group(EC_KEY *ec, EC_GROUP *group)
 918 {
 919     if (group == NULL) {
 920         ERR_raise(ERR_LIB_PROV, PROV_R_NO_PARAMETERS_SET);
 921         return 0;
 922     }
 923     return EC_KEY_set_group(ec, group) > 0;
 924 }
 925
 926 /*
 927  * The callback arguments (osslcb & cbarg) are not used by EC_KEY generation
 928  */
 929 static void *ec_gen(void *genctx, OSSL_CALLBACK *osslcb, void *cbarg)
 930 {
 931     struct ec_gen_ctx *gctx = genctx;
 932     EC_KEY *ec = NULL;
 933     int ret = 0;
 934
 935     if (gctx == NULL
 936         || (ec = EC_KEY_new_with_libctx(gctx->libctx, NULL)) == NULL)
 937         return NULL;
 938
 939     if (gctx->gen_group == NULL) {
 940         if (!ec_gen_set_group_from_params(gctx))
 941             goto err;
 942     } else {
 943         if (gctx->encoding) {
 944             int flags = ec_encoding_name2id(gctx->encoding);
 945             if (flags < 0)
 946                 goto err;
 947             EC_GROUP_set_asn1_flag(gctx->gen_group, flags);
 948         }
 949     }
 950
 951     /* We must always assign a group, no matter what */
 952     ret = ec_gen_assign_group(ec, gctx->gen_group);
 953
 954     /* Whether you want it or not, you get a keypair, not just one half */
 955     if ((gctx->selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0)
 956         ret = ret && EC_KEY_generate_key(ec);
 957
 958     if (gctx->ecdh_mode != -1)
 959         ret = ret && ec_set_ecdh_cofactor_mode(ec, gctx->ecdh_mode);
 960
 961     if (ret)
 962         return ec;
 963 err:
 964     /* Something went wrong, throw the key away */
 965     EC_KEY_free(ec);
 966     return NULL;
 967 }
 968
 969 static void ec_gen_cleanup(void *genctx)
 970 {
 971     struct ec_gen_ctx *gctx = genctx;
 972
 973     if (gctx == NULL)
 974         return;
 975
 976     EC_GROUP_free(gctx->gen_group);
 977     BN_free(gctx->p);
 978     BN_free(gctx->a);
 979     BN_free(gctx->b);
 980     BN_free(gctx->order);
 981     BN_free(gctx->cofactor);
 982     OPENSSL_free(gctx->group_name);
 983     OPENSSL_free(gctx->field_type);;
 984     OPENSSL_free(gctx->encoding);
 985     OPENSSL_free(gctx->seed);
 986     OPENSSL_free(gctx->gen);
 987     OPENSSL_free(gctx);
 988 }
 989
 990 void *ec_load(const void *reference, size_t reference_sz)
 991 {
 992     EC_KEY *ec = NULL;
 993
 994     if (reference_sz == sizeof(ec)) {
 995         /* The contents of the reference is the address to our object */
 996         ec = *(EC_KEY **)reference;
 997         /* We grabbed, so we detach it */
 998         *(EC_KEY **)reference = NULL;
 999         return ec;
1000     }
1001     return NULL;
1002 }
1003
1004 const OSSL_DISPATCH ec_keymgmt_functions[] = {
1005     { OSSL_FUNC_KEYMGMT_NEW, (void (*)(void))ec_newdata },
1006     { OSSL_FUNC_KEYMGMT_GEN_INIT, (void (*)(void))ec_gen_init },
1007     { OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE,
1008       (void (*)(void))ec_gen_set_template },
1009     { OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS, (void (*)(void))ec_gen_set_params },
1010     { OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS,
1011       (void (*)(void))ec_gen_settable_params },
1012     { OSSL_FUNC_KEYMGMT_GEN, (void (*)(void))ec_gen },
1013     { OSSL_FUNC_KEYMGMT_GEN_CLEANUP, (void (*)(void))ec_gen_cleanup },
1014     { OSSL_FUNC_KEYMGMT_LOAD, (void (*)(void))ec_load },
1015     { OSSL_FUNC_KEYMGMT_FREE, (void (*)(void))ec_freedata },
1016     { OSSL_FUNC_KEYMGMT_GET_PARAMS, (void (*) (void))ec_get_params },
1017     { OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS, (void (*) (void))ec_gettable_params },
1018     { OSSL_FUNC_KEYMGMT_SET_PARAMS, (void (*) (void))ec_set_params },
1019     { OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS, (void (*) (void))ec_settable_params },
1020     { OSSL_FUNC_KEYMGMT_HAS, (void (*)(void))ec_has },
1021     { OSSL_FUNC_KEYMGMT_MATCH, (void (*)(void))ec_match },
1022     { OSSL_FUNC_KEYMGMT_VALIDATE, (void (*)(void))ec_validate },
1023     { OSSL_FUNC_KEYMGMT_IMPORT, (void (*)(void))ec_import },
1024     { OSSL_FUNC_KEYMGMT_IMPORT_TYPES, (void (*)(void))ec_import_types },
1025     { OSSL_FUNC_KEYMGMT_EXPORT, (void (*)(void))ec_export },
1026     { OSSL_FUNC_KEYMGMT_EXPORT_TYPES, (void (*)(void))ec_export_types },
1027     { OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME,
1028       (void (*)(void))ec_query_operation_name },
1029     { 0, NULL }
1030 };