text: /*
   * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  /*
   * ECDH/ECDSA low level APIs are deprecated for public use, but still ok for
   * internal use.
   */
  #include "internal/deprecated.h"
  
  #include <openssl/core_numbers.h>
  #include <openssl/core_names.h>
  #include <openssl/bn.h>
  #include <openssl/err.h>
  #include <openssl/objects.h>
  #include "crypto/bn.h"
  #include "crypto/ec.h"
  #include "prov/implementations.h"
  #include "prov/providercommon.h"
  #include "prov/providercommonerr.h"
  #include "prov/provider_ctx.h"
  #include "internal/param_build_set.h"
  
  static OSSL_OP_keymgmt_new_fn ec_newdata;
  static OSSL_OP_keymgmt_gen_init_fn ec_gen_init;
  static OSSL_OP_keymgmt_gen_set_template_fn ec_gen_set_template;
  static OSSL_OP_keymgmt_gen_set_params_fn ec_gen_set_params;
  static OSSL_OP_keymgmt_gen_settable_params_fn ec_gen_settable_params;
  static OSSL_OP_keymgmt_gen_fn ec_gen;
  static OSSL_OP_keymgmt_gen_cleanup_fn ec_gen_cleanup;
  static OSSL_OP_keymgmt_free_fn ec_freedata;
  static OSSL_OP_keymgmt_get_params_fn ec_get_params;
  static OSSL_OP_keymgmt_gettable_params_fn ec_gettable_params;
  static OSSL_OP_keymgmt_set_params_fn ec_set_params;
  static OSSL_OP_keymgmt_settable_params_fn ec_settable_params;
  static OSSL_OP_keymgmt_has_fn ec_has;
  static OSSL_OP_keymgmt_match_fn ec_match;
  static OSSL_OP_keymgmt_validate_fn ec_validate;
  static OSSL_OP_keymgmt_import_fn ec_import;
  static OSSL_OP_keymgmt_import_types_fn ec_import_types;
  static OSSL_OP_keymgmt_export_fn ec_export;
  static OSSL_OP_keymgmt_export_types_fn ec_export_types;
  static OSSL_OP_keymgmt_query_operation_name_fn ec_query_operation_name;
  
  #define EC_DEFAULT_MD "SHA256"
  #define EC_POSSIBLE_SELECTIONS                                                 \
      (OSSL_KEYMGMT_SELECT_KEYPAIR | OSSL_KEYMGMT_SELECT_ALL_PARAMETERS)
  
  static
  const char *ec_query_operation_name(int operation_id)
  {
      switch (operation_id) {
      case OSSL_OP_KEYEXCH:
          return "ECDH";
      case OSSL_OP_SIGNATURE:
          return "ECDSA";
      }
      return NULL;
  }
  
  static ossl_inline
  int domparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl,
                          OSSL_PARAM params[])
  {
      const EC_GROUP *ecg;
      int curve_nid;
  
      if (ec == NULL)
          return 0;
  
      ecg = EC_KEY_get0_group(ec);
      if (ecg == NULL)
          return 0;
  
      curve_nid = EC_GROUP_get_curve_name(ecg);
  
      if (curve_nid == NID_undef) {
          /* TODO(3.0): should we support explicit parameters curves? */
          return 0;
      } else {
          /* named curve */
          const char *curve_name = NULL;
  
          if ((curve_name = ec_curve_nid2name(curve_nid)) == NULL)
              return 0;
          if (!ossl_param_build_set_utf8_string(tmpl, params,
                                                OSSL_PKEY_PARAM_GROUP_NAME,
                                                curve_name))
  
              return 0;
      }
  
      return 1;
  }
  
  /*
   * Callers of key_to_params MUST make sure that domparams_to_params is also
   * called!
   *
   * This function only exports the bare keypair, domain parameters and other
   * parameters are exported separately.
   */
  static ossl_inline
  int key_to_params(const EC_KEY *eckey, OSSL_PARAM_BLD *tmpl,
                    OSSL_PARAM params[], int include_private,
                    unsigned char **pub_key)
  {
      BIGNUM *x = NULL, *y = NULL;
      const BIGNUM *priv_key = NULL;
      const EC_POINT *pub_point = NULL;
      const EC_GROUP *ecg = NULL;
      size_t pub_key_len = 0;
      int ret = 0;
      BN_CTX *bnctx = NULL;
  
      if (eckey == NULL
          || (ecg = EC_KEY_get0_group(eckey)) == NULL)
          return 0;
  
      priv_key = EC_KEY_get0_private_key(eckey);
      pub_point = EC_KEY_get0_public_key(eckey);
  
      if (pub_point != NULL) {
          OSSL_PARAM *p = NULL, *px = NULL, *py = NULL;
          /*
           * EC_POINT_point2buf() can generate random numbers in some
           * implementations so we need to ensure we use the correct libctx.
           */
          bnctx = BN_CTX_new_ex(ec_key_get_libctx(eckey));
          if (bnctx == NULL)
              goto err;
  
  
          /* If we are doing a get then check first before decoding the point */
          if (tmpl == NULL) {
              p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_PUB_KEY);
              px = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_EC_PUB_X);
              py = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_EC_PUB_Y);
          }
  
          if (p != NULL || tmpl != NULL) {
              /* convert pub_point to a octet string according to the SECG standard */
              if ((pub_key_len = EC_POINT_point2buf(ecg, pub_point,
                                                    POINT_CONVERSION_COMPRESSED,
                                                    pub_key, bnctx)) == 0
                  || !ossl_param_build_set_octet_string(tmpl, p,
                                                        OSSL_PKEY_PARAM_PUB_KEY,
                                                        *pub_key, pub_key_len))
                  goto err;
          }
          if (px != NULL || py != NULL) {
              if (px != NULL)
                  x = BN_CTX_get(bnctx);
              if (py != NULL)
                  y = BN_CTX_get(bnctx);
  
              if (!EC_POINT_get_affine_coordinates(ecg, pub_point, x, y, bnctx))
                  goto err;
              if (px != NULL
                  && !ossl_param_build_set_bn(tmpl, px,
                                              OSSL_PKEY_PARAM_EC_PUB_X, x))
                  goto err;
              if (py != NULL
                  && !ossl_param_build_set_bn(tmpl, py,
                                              OSSL_PKEY_PARAM_EC_PUB_Y, y))
                  goto err;
          }
      }
  
      if (priv_key != NULL && include_private) {
          size_t sz;
          int ecbits;
  
          /*
           * Key import/export should never leak the bit length of the secret
           * scalar in the key.
           *
           * For this reason, on export we use padded BIGNUMs with fixed length.
           *
           * When importing we also should make sure that, even if short lived,
           * the newly created BIGNUM is marked with the BN_FLG_CONSTTIME flag as
           * soon as possible, so that any processing of this BIGNUM might opt for
           * constant time implementations in the backend.
           *
           * Setting the BN_FLG_CONSTTIME flag alone is never enough, we also have
           * to preallocate the BIGNUM internal buffer to a fixed public size big
           * enough that operations performed during the processing never trigger
           * a realloc which would leak the size of the scalar through memory
           * accesses.
           *
           * Fixed Length
           * ------------
           *
           * The order of the large prime subgroup of the curve is our choice for
           * a fixed public size, as that is generally the upper bound for
           * generating a private key in EC cryptosystems and should fit all valid
           * secret scalars.
           *
           * For padding on export we just use the bit length of the order
           * converted to bytes (rounding up).
           *
           * For preallocating the BIGNUM storage we look at the number of "words"
           * required for the internal representation of the order, and we
           * preallocate 2 extra "words" in case any of the subsequent processing
           * might temporarily overflow the order length.
           */
          ecbits = EC_GROUP_order_bits(ecg);
          if (ecbits <= 0)
              goto err;
          sz = (ecbits + 7 ) / 8;
  
          if (!ossl_param_build_set_bn_pad(tmpl, params,
                                           OSSL_PKEY_PARAM_PRIV_KEY,
                                           priv_key, sz))
              goto err;
      }
      ret = 1;
   err:
      BN_CTX_free(bnctx);
      return ret;
  }
  
  static ossl_inline
  int otherparams_to_params(const EC_KEY *ec, OSSL_PARAM_BLD *tmpl,
                            OSSL_PARAM params[])
  {
      int ecdh_cofactor_mode = 0;
  
      if (ec == NULL)
          return 0;
  
      ecdh_cofactor_mode =
          (EC_KEY_get_flags(ec) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
      return ossl_param_build_set_int(tmpl, params,
                                      OSSL_PKEY_PARAM_USE_COFACTOR_ECDH,
                                      ecdh_cofactor_mode);
  }
  
  static
  void *ec_newdata(void *provctx)
  {
      return EC_KEY_new_with_libctx(PROV_LIBRARY_CONTEXT_OF(provctx), NULL);
  }
  
  static
  void ec_freedata(void *keydata)
  {
      EC_KEY_free(keydata);
  }
  
  static
  int ec_has(void *keydata, int selection)
  {
      EC_KEY *ec = keydata;
      int ok = 0;
  
      if (ec != NULL) {
          if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
              ok = 1;
  
          if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
              ok = ok && (EC_KEY_get0_public_key(ec) != NULL);
          if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
              ok = ok && (EC_KEY_get0_private_key(ec) != NULL);
          if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
              ok = ok && (EC_KEY_get0_group(ec) != NULL);
          /*
           * We consider OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS to always be
           * available, so no extra check is needed other than the previous one
           * against EC_POSSIBLE_SELECTIONS.
           */
      }
      return ok;
  }
  
  static int ec_match(const void *keydata1, const void *keydata2, int selection)
  {
      const EC_KEY *ec1 = keydata1;
      const EC_KEY *ec2 = keydata2;
      const EC_GROUP *group_a = EC_KEY_get0_group(ec1);
      const EC_GROUP *group_b = EC_KEY_get0_group(ec2);
      int ok = 1;
  
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
          ok = ok && group_a != NULL && group_b != NULL
              && EC_GROUP_cmp(group_a, group_b, NULL) == 0;
      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {
          const BIGNUM *pa = EC_KEY_get0_private_key(ec1);
          const BIGNUM *pb = EC_KEY_get0_private_key(ec2);
  
          ok = ok && BN_cmp(pa, pb) == 0;
      }
      if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0) {
          const EC_POINT *pa = EC_KEY_get0_public_key(ec1);
          const EC_POINT *pb = EC_KEY_get0_public_key(ec2);
  
          ok = ok && EC_POINT_cmp(group_b, pa, pb, NULL);
      }
      return ok;
  }
  
  static
  int ec_import(void *keydata, int selection, const OSSL_PARAM params[])
  {
      EC_KEY *ec = keydata;
      int ok = 1;
  
      if (ec == NULL)
          return 0;
  
      /*
       * In this implementation, we can export/import only keydata in the
       * following combinations:
       *   - domain parameters only
       *   - public key with associated domain parameters (+optional other params)
       *   - private key with associated public key and domain parameters
       *         (+optional other params)
       *
       * This means:
       *   - domain parameters must always be requested
       *   - private key must be requested alongside public key
       *   - other parameters must be requested only alongside a key
       */
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
          return 0;
      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
              && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
          return 0;
      if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
              && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
          return 0;
  
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
          ok = ok && ec_key_domparams_fromdata(ec, params);
      if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
          int include_private =
              selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
  
          ok = ok && ec_key_fromdata(ec, params, include_private);
      }
      if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
          ok = ok && ec_key_otherparams_fromdata(ec, params);
  
      return ok;
  }
  
  static
  int ec_export(void *keydata, int selection, OSSL_CALLBACK *param_cb,
                void *cbarg)
  {
      EC_KEY *ec = keydata;
      OSSL_PARAM_BLD *tmpl;
      OSSL_PARAM *params = NULL;
      unsigned char *pub_key = NULL;
      int ok = 1;
  
      if (ec == NULL)
          return 0;
  
      /*
       * In this implementation, we can export/import only keydata in the
       * following combinations:
       *   - domain parameters only
       *   - public key with associated domain parameters (+optional other params)
       *   - private key with associated public key and domain parameters
       *         (+optional other params)
       *
       * This means:
       *   - domain parameters must always be requested
       *   - private key must be requested alongside public key
       *   - other parameters must be requested only alongside a key
       */
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0)
          return 0;
      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
              && (selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) == 0)
          return 0;
      if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0
              && (selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == 0)
          return 0;
  
      tmpl = OSSL_PARAM_BLD_new();
      if (tmpl == NULL)
          return 0;
  
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
          ok = ok && domparams_to_params(ec, tmpl, NULL);
  
      if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
          int include_private =
              selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY ? 1 : 0;
  
          ok = ok && key_to_params(ec, tmpl, NULL, include_private, &pub_key);
      }
      if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
          ok = ok && otherparams_to_params(ec, tmpl, NULL);
  
      if (ok && (params = OSSL_PARAM_BLD_to_param(tmpl)) != NULL)
          ok = param_cb(params, cbarg);
  
      OSSL_PARAM_BLD_free_params(params);
      OSSL_PARAM_BLD_free(tmpl);
      OPENSSL_free(pub_key);
      return ok;
  }
  
  /* IMEXPORT = IMPORT + EXPORT */
  
  # define EC_IMEXPORTABLE_DOM_PARAMETERS                          \
      OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME, NULL, 0)
  # define EC_IMEXPORTABLE_PUBLIC_KEY                              \
      OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_PUB_KEY, NULL, 0)
  # define EC_IMEXPORTABLE_PRIVATE_KEY                             \
      OSSL_PARAM_BN(OSSL_PKEY_PARAM_PRIV_KEY, NULL, 0)
  # define EC_IMEXPORTABLE_OTHER_PARAMETERS                        \
      OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL)
  
  /*
   * Include all the possible combinations of OSSL_PARAM arrays for
   * ec_imexport_types().
   *
   * They are in a separate file as it is ~100 lines of unreadable and
   * uninteresting machine generated stuff.
   *
   * TODO(3.0): the generated list looks quite ugly, as to cover all possible
   * combinations of the bits in `selection`, it also includes combinations that
   * are not really useful: we might want to consider alternatives to this
   * solution.
   */
  #include "ec_kmgmt_imexport.inc"
  
  static ossl_inline
  const OSSL_PARAM *ec_imexport_types(int selection)
  {
      int type_select = 0;
  
      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
          type_select += 1;
      if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
          type_select += 2;
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
          type_select += 4;
      if ((selection & OSSL_KEYMGMT_SELECT_OTHER_PARAMETERS) != 0)
          type_select += 8;
      return ec_types[type_select];
  }
  
  static
  const OSSL_PARAM *ec_import_types(int selection)
  {
      return ec_imexport_types(selection);
  }
  
  static
  const OSSL_PARAM *ec_export_types(int selection)
  {
      return ec_imexport_types(selection);
  }
  
  static
  int ec_get_params(void *key, OSSL_PARAM params[])
  {
      int ret;
      EC_KEY *eck = key;
      const EC_GROUP *ecg = NULL;
      OSSL_PARAM *p;
      unsigned char *pub_key = NULL;
  
      ecg = EC_KEY_get0_group(eck);
      if (ecg == NULL)
          return 0;
  
      if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_MAX_SIZE)) != NULL
          && !OSSL_PARAM_set_int(p, ECDSA_size(eck)))
          return 0;
      if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_BITS)) != NULL
          && !OSSL_PARAM_set_int(p, EC_GROUP_order_bits(ecg)))
          return 0;
      if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_SECURITY_BITS)) != NULL) {
          int ecbits, sec_bits;
  
          ecbits = EC_GROUP_order_bits(ecg);
  
          /*
           * The following estimates are based on the values published
           * in Table 2 of "NIST Special Publication 800-57 Part 1 Revision 4"
           * at http://dx.doi.org/10.6028/NIST.SP.800-57pt1r4 .
           *
           * Note that the above reference explicitly categorizes algorithms in a
           * discrete set of values {80, 112, 128, 192, 256}, and that it is
           * relevant only for NIST approved Elliptic Curves, while OpenSSL
           * applies the same logic also to other curves.
           *
           * Classifications produced by other standardazing bodies might differ,
           * so the results provided for "bits of security" by this provider are
           * to be considered merely indicative, and it is the users'
           * responsibility to compare these values against the normative
           * references that may be relevant for their intent and purposes.
           */
          if (ecbits >= 512)
              sec_bits = 256;
          else if (ecbits >= 384)
              sec_bits = 192;
          else if (ecbits >= 256)
              sec_bits = 128;
          else if (ecbits >= 224)
              sec_bits = 112;
          else if (ecbits >= 160)
              sec_bits = 80;
          else
              sec_bits = ecbits / 2;
  
          if (!OSSL_PARAM_set_int(p, sec_bits))
              return 0;
      }
  
      if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_DEFAULT_DIGEST)) != NULL
          && !OSSL_PARAM_set_utf8_string(p, EC_DEFAULT_MD))
          return 0;
  
      p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH);
      if (p != NULL) {
          int ecdh_cofactor_mode = 0;
  
          ecdh_cofactor_mode =
              (EC_KEY_get_flags(eck) & EC_FLAG_COFACTOR_ECDH) ? 1 : 0;
  
          if (!OSSL_PARAM_set_int(p, ecdh_cofactor_mode))
              return 0;
      }
      if ((p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_TLS_ENCODED_PT)) != NULL) {
          BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(key));
  
          if (ctx == NULL)
              return 0;
          p->return_size = EC_POINT_point2oct(EC_KEY_get0_group(key),
                                              EC_KEY_get0_public_key(key),
                                              POINT_CONVERSION_UNCOMPRESSED,
                                              p->data, p->return_size, ctx);
          BN_CTX_free(ctx);
          if (p->return_size == 0)
              return 0;
      }
  
      ret = domparams_to_params(eck, NULL, params)
            && key_to_params(eck, NULL, params, 1, &pub_key)
            && otherparams_to_params(eck, NULL, params);
      OPENSSL_free(pub_key);
      return ret;
  }
  
  static const OSSL_PARAM ec_known_gettable_params[] = {
      OSSL_PARAM_int(OSSL_PKEY_PARAM_BITS, NULL),
      OSSL_PARAM_int(OSSL_PKEY_PARAM_SECURITY_BITS, NULL),
      OSSL_PARAM_int(OSSL_PKEY_PARAM_MAX_SIZE, NULL),
      OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_TLS_ENCODED_PT, NULL, 0),
      EC_IMEXPORTABLE_DOM_PARAMETERS,
      EC_IMEXPORTABLE_PUBLIC_KEY,
      OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_PUB_X, NULL, 0),
      OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_EC_PUB_Y, NULL, 0),
      EC_IMEXPORTABLE_PRIVATE_KEY,
      EC_IMEXPORTABLE_OTHER_PARAMETERS,
      OSSL_PARAM_END
  };
  
  static
  const OSSL_PARAM *ec_gettable_params(void)
  {
      return ec_known_gettable_params;
  }
  
  static const OSSL_PARAM ec_known_settable_params[] = {
      OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
      OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_TLS_ENCODED_PT, NULL, 0),
      OSSL_PARAM_END
  };
  
  static
  const OSSL_PARAM *ec_settable_params(void)
  {
      return ec_known_settable_params;
  }
  
  static
  int ec_set_params(void *key, const OSSL_PARAM params[])
  {
      EC_KEY *eck = key;
      const OSSL_PARAM *p;
  
      p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_TLS_ENCODED_PT);
      if (p != NULL) {
          BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(key));
          int ret = 1;
  
          if (ctx == NULL
                  || p->data_type != OSSL_PARAM_OCTET_STRING
                  || !EC_KEY_oct2key(key, p->data, p->data_size, ctx))
              ret = 0;
          BN_CTX_free(ctx);
          if (!ret)
              return 0;
      }
  
      return ec_key_otherparams_fromdata(eck, params);
  }
  
  static
  int ec_validate(void *keydata, int selection)
  {
      EC_KEY *eck = keydata;
      int ok = 0;
      BN_CTX *ctx = BN_CTX_new_ex(ec_key_get_libctx(eck));
  
      if (ctx == NULL)
          return 0;
  
      if ((selection & EC_POSSIBLE_SELECTIONS) != 0)
          ok = 1;
  
      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0)
          ok = ok && EC_GROUP_check(EC_KEY_get0_group(eck), ctx);
  
      if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0)
          ok = ok && ec_key_public_check(eck, ctx);
  
      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0)
          ok = ok && ec_key_private_check(eck);
  
      if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) == OSSL_KEYMGMT_SELECT_KEYPAIR)
          ok = ok && ec_key_pairwise_check(eck, ctx);
  
      BN_CTX_free(ctx);
      return ok;
  }
  
  struct ec_gen_ctx {
      OPENSSL_CTX *libctx;
      EC_GROUP *gen_group;
      int selection;
      int ecdh_mode;
  };
  
  static void *ec_gen_init(void *provctx, int selection)
  {
      OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(provctx);
      struct ec_gen_ctx *gctx = NULL;
  
      if ((selection & (EC_POSSIBLE_SELECTIONS)) == 0)
          return NULL;
  
      if ((gctx = OPENSSL_zalloc(sizeof(*gctx))) != NULL) {
          gctx->libctx = libctx;
          gctx->gen_group = NULL;
          gctx->selection = selection;
          gctx->ecdh_mode = 0;
      }
      return gctx;
  }
  
  static int ec_gen_set_group(void *genctx, int nid)
  {
      struct ec_gen_ctx *gctx = genctx;
      EC_GROUP *group;
  
      group = EC_GROUP_new_by_curve_name_with_libctx(gctx->libctx, NULL, nid);
      if (group == NULL) {
          ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
          return 0;
      }
      EC_GROUP_free(gctx->gen_group);
      gctx->gen_group = group;
      return 1;
  }
  static int ec_gen_set_template(void *genctx, void *templ)
  {
      struct ec_gen_ctx *gctx = genctx;
      EC_KEY *ec = templ;
      const EC_GROUP *ec_group;
  
      if (gctx == NULL || ec == NULL)
          return 0;
      if ((ec_group = EC_KEY_get0_group(ec)) == NULL)
          return 0;
      return ec_gen_set_group(gctx, EC_GROUP_get_curve_name(ec_group));
  }
  
  static int ec_gen_set_params(void *genctx, const OSSL_PARAM params[])
  {
      struct ec_gen_ctx *gctx = genctx;
      const OSSL_PARAM *p;
  
      if ((p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_USE_COFACTOR_ECDH))
          != NULL) {
          if (!OSSL_PARAM_get_int(p, &gctx->ecdh_mode))
              return 0;
      }
      if ((p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_GROUP_NAME))
          != NULL) {
          const char *curve_name = NULL;
          int ret = 0;
  
          switch (p->data_type) {
          case OSSL_PARAM_UTF8_STRING:
              /* The OSSL_PARAM functions have no support for this */
              curve_name = p->data;
              ret = (curve_name != NULL);
              break;
          case OSSL_PARAM_UTF8_PTR:
              ret = OSSL_PARAM_get_utf8_ptr(p, &curve_name);
              break;
          }
  
          if (ret) {
              int nid = ec_curve_name2nid(curve_name);
  
              if (nid == NID_undef) {
                  ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CURVE);
                  ret = 0;
              } else {
                  ret = ec_gen_set_group(gctx, nid);
              }
          }
          return ret;
      }
      return 1;
  }
  
  static const OSSL_PARAM *ec_gen_settable_params(void *provctx)
  {
      static OSSL_PARAM settable[] = {
          OSSL_PARAM_utf8_string(OSSL_PKEY_PARAM_GROUP_NAME, NULL, 0),
          OSSL_PARAM_int(OSSL_PKEY_PARAM_USE_COFACTOR_ECDH, NULL),
          OSSL_PARAM_END
      };
  
      return settable;
  }
  
  static int ec_gen_assign_group(EC_KEY *ec, EC_GROUP *group)
  {
      if (group == NULL) {
          ERR_raise(ERR_LIB_PROV, PROV_R_NO_PARAMETERS_SET);
          return 0;
      }
      return EC_KEY_set_group(ec, group) > 0;
  }
  
  /*
   * The callback arguments (osslcb & cbarg) are not used by EC_KEY generation
   */
  static void *ec_gen(void *genctx, OSSL_CALLBACK *osslcb, void *cbarg)
  {
      struct ec_gen_ctx *gctx = genctx;
      EC_KEY *ec = NULL;
      int ret = 1;                 /* Start optimistically */
  
      if (gctx == NULL
          || (ec = EC_KEY_new_with_libctx(gctx->libctx, NULL)) == NULL)
          return NULL;
  
      /* We must always assign a group, no matter what */
      ret = ec_gen_assign_group(ec, gctx->gen_group);
      /* Whether you want it or not, you get a keypair, not just one half */
      if ((gctx->selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0)
          ret = ret && EC_KEY_generate_key(ec);
  
      if (gctx->ecdh_mode != -1)
          ret = ret && ec_set_ecdh_cofactor_mode(ec, gctx->ecdh_mode);
  
      if (ret)
          return ec;
  
      /* Something went wrong, throw the key away */
      EC_KEY_free(ec);
      return NULL;
  }
  
  static void ec_gen_cleanup(void *genctx)
  {
      struct ec_gen_ctx *gctx = genctx;
  
      if (gctx == NULL)
          return;
  
      EC_GROUP_free(gctx->gen_group);
      OPENSSL_free(gctx);
  }
  
  const OSSL_DISPATCH ec_keymgmt_functions[] = {
      { OSSL_FUNC_KEYMGMT_NEW, (void (*)(void))ec_newdata },
      { OSSL_FUNC_KEYMGMT_GEN_INIT, (void (*)(void))ec_gen_init },
      { OSSL_FUNC_KEYMGMT_GEN_SET_TEMPLATE,
        (void (*)(void))ec_gen_set_template },
      { OSSL_FUNC_KEYMGMT_GEN_SET_PARAMS, (void (*)(void))ec_gen_set_params },
      { OSSL_FUNC_KEYMGMT_GEN_SETTABLE_PARAMS,
        (void (*)(void))ec_gen_settable_params },
      { OSSL_FUNC_KEYMGMT_GEN, (void (*)(void))ec_gen },
      { OSSL_FUNC_KEYMGMT_GEN_CLEANUP, (void (*)(void))ec_gen_cleanup },
      { OSSL_FUNC_KEYMGMT_FREE, (void (*)(void))ec_freedata },
      { OSSL_FUNC_KEYMGMT_GET_PARAMS, (void (*) (void))ec_get_params },
      { OSSL_FUNC_KEYMGMT_GETTABLE_PARAMS, (void (*) (void))ec_gettable_params },
      { OSSL_FUNC_KEYMGMT_SET_PARAMS, (void (*) (void))ec_set_params },
      { OSSL_FUNC_KEYMGMT_SETTABLE_PARAMS, (void (*) (void))ec_settable_params },
      { OSSL_FUNC_KEYMGMT_HAS, (void (*)(void))ec_has },
      { OSSL_FUNC_KEYMGMT_MATCH, (void (*)(void))ec_match },
      { OSSL_FUNC_KEYMGMT_VALIDATE, (void (*)(void))ec_validate },
      { OSSL_FUNC_KEYMGMT_IMPORT, (void (*)(void))ec_import },
      { OSSL_FUNC_KEYMGMT_IMPORT_TYPES, (void (*)(void))ec_import_types },
      { OSSL_FUNC_KEYMGMT_EXPORT, (void (*)(void))ec_export },
      { OSSL_FUNC_KEYMGMT_EXPORT_TYPES, (void (*)(void))ec_export_types },
      { OSSL_FUNC_KEYMGMT_QUERY_OPERATION_NAME,
        (void (*)(void))ec_query_operation_name },
      { 0, NULL }
  };
  