text: /*
   * Copyright 2006-2019 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the OpenSSL license (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
   */
  
  #include <stdio.h>
  #include "internal/cryptlib.h"
  #include <openssl/x509.h>
  #include <openssl/ec.h>
  #include <openssl/bn.h>
  #include <openssl/cms.h>
  #include <openssl/asn1t.h>
  #include "crypto/asn1.h"
  #include "crypto/evp.h"
  #include "ec_local.h"
  
  #ifndef OPENSSL_NO_CMS
  static int ecdh_cms_decrypt(CMS_RecipientInfo *ri);
  static int ecdh_cms_encrypt(CMS_RecipientInfo *ri);
  #endif
  
  static int eckey_param2type(int *pptype, void **ppval, const EC_KEY *ec_key)
  {
      const EC_GROUP *group;
      int nid;
      if (ec_key == NULL || (group = EC_KEY_get0_group(ec_key)) == NULL) {
          ECerr(EC_F_ECKEY_PARAM2TYPE, EC_R_MISSING_PARAMETERS);
          return 0;
      }
      if (EC_GROUP_get_asn1_flag(group)
          && (nid = EC_GROUP_get_curve_name(group)))
          /* we have a 'named curve' => just set the OID */
      {
          *ppval = OBJ_nid2obj(nid);
          *pptype = V_ASN1_OBJECT;
      } else {                    /* explicit parameters */
  
          ASN1_STRING *pstr = NULL;
          pstr = ASN1_STRING_new();
          if (pstr == NULL)
              return 0;
  
          /*
           * The cast in the following line is intentional as the
           * `i2d_ECParameters` signature can't be constified (see discussion at
           * https://github.com/openssl/openssl/pull/9347 where related and
           * required constification backports were rejected).
           *
           * This cast should be safe anyway, because we can expect
           * `i2d_ECParameters()` to treat the first argument as if it was const.
           */
          pstr->length = i2d_ECParameters((EC_KEY *)ec_key, &pstr->data);
          if (pstr->length <= 0) {
              ASN1_STRING_free(pstr);
              ECerr(EC_F_ECKEY_PARAM2TYPE, ERR_R_EC_LIB);
              return 0;
          }
          *ppval = pstr;
          *pptype = V_ASN1_SEQUENCE;
      }
      return 1;
  }
  
  static int eckey_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
  {
      const EC_KEY *ec_key = pkey->pkey.ec;
      void *pval = NULL;
      int ptype;
      unsigned char *penc = NULL, *p;
      int penclen;
  
      if (!eckey_param2type(&ptype, &pval, ec_key)) {
          ECerr(EC_F_ECKEY_PUB_ENCODE, ERR_R_EC_LIB);
          return 0;
      }
      penclen = i2o_ECPublicKey(ec_key, NULL);
      if (penclen <= 0)
          goto err;
      penc = OPENSSL_malloc(penclen);
      if (penc == NULL)
          goto err;
      p = penc;
      penclen = i2o_ECPublicKey(ec_key, &p);
      if (penclen <= 0)
          goto err;
      if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_EC),
                                 ptype, pval, penc, penclen))
          return 1;
   err:
      if (ptype == V_ASN1_OBJECT)
          ASN1_OBJECT_free(pval);
      else
          ASN1_STRING_free(pval);
      OPENSSL_free(penc);
      return 0;
  }
  
  static EC_KEY *eckey_type2param(int ptype, const void *pval)
  {
      EC_KEY *eckey = NULL;
      EC_GROUP *group = NULL;
  
      if (ptype == V_ASN1_SEQUENCE) {
          const ASN1_STRING *pstr = pval;
          const unsigned char *pm = pstr->data;
          int pmlen = pstr->length;
  
          if ((eckey = d2i_ECParameters(NULL, &pm, pmlen)) == NULL) {
              ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
              goto ecerr;
          }
      } else if (ptype == V_ASN1_OBJECT) {
          const ASN1_OBJECT *poid = pval;
  
          /*
           * type == V_ASN1_OBJECT => the parameters are given by an asn1 OID
           */
          if ((eckey = EC_KEY_new()) == NULL) {
              ECerr(EC_F_ECKEY_TYPE2PARAM, ERR_R_MALLOC_FAILURE);
              goto ecerr;
          }
          group = EC_GROUP_new_by_curve_name(OBJ_obj2nid(poid));
          if (group == NULL)
              goto ecerr;
          EC_GROUP_set_asn1_flag(group, OPENSSL_EC_NAMED_CURVE);
          if (EC_KEY_set_group(eckey, group) == 0)
              goto ecerr;
          EC_GROUP_free(group);
      } else {
          ECerr(EC_F_ECKEY_TYPE2PARAM, EC_R_DECODE_ERROR);
          goto ecerr;
      }
  
      return eckey;
  
   ecerr:
      EC_KEY_free(eckey);
      EC_GROUP_free(group);
      return NULL;
  }
  
  static int eckey_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
  {
      const unsigned char *p = NULL;
      const void *pval;
      int ptype, pklen;
      EC_KEY *eckey = NULL;
      X509_ALGOR *palg;
  
      if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
          return 0;
      X509_ALGOR_get0(NULL, &ptype, &pval, palg);
  
      eckey = eckey_type2param(ptype, pval);
  
      if (!eckey) {
          ECerr(EC_F_ECKEY_PUB_DECODE, ERR_R_EC_LIB);
          return 0;
      }
  
      /* We have parameters now set public key */
      if (!o2i_ECPublicKey(&eckey, &p, pklen)) {
          ECerr(EC_F_ECKEY_PUB_DECODE, EC_R_DECODE_ERROR);
          goto ecerr;
      }
  
      EVP_PKEY_assign_EC_KEY(pkey, eckey);
      return 1;
  
   ecerr:
      EC_KEY_free(eckey);
      return 0;
  }
  
  static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
  {
      int r;
      const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
      const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
          *pb = EC_KEY_get0_public_key(b->pkey.ec);
      if (group == NULL || pa == NULL || pb == NULL)
          return -2;
      r = EC_POINT_cmp(group, pa, pb, NULL);
      if (r == 0)
          return 1;
      if (r == 1)
          return 0;
      return -2;
  }
  
  static int eckey_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
  {
      const unsigned char *p = NULL;
      const void *pval;
      int ptype, pklen;
      EC_KEY *eckey = NULL;
      const X509_ALGOR *palg;
  
      if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
          return 0;
      X509_ALGOR_get0(NULL, &ptype, &pval, palg);
  
      eckey = eckey_type2param(ptype, pval);
  
      if (!eckey)
          goto ecliberr;
  
      /* We have parameters now set private key */
      if (!d2i_ECPrivateKey(&eckey, &p, pklen)) {
          ECerr(EC_F_ECKEY_PRIV_DECODE, EC_R_DECODE_ERROR);
          goto ecerr;
      }
  
      EVP_PKEY_assign_EC_KEY(pkey, eckey);
      return 1;
  
   ecliberr:
      ECerr(EC_F_ECKEY_PRIV_DECODE, ERR_R_EC_LIB);
   ecerr:
      EC_KEY_free(eckey);
      return 0;
  }
  
  static int eckey_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
  {
      EC_KEY ec_key = *(pkey->pkey.ec);
      unsigned char *ep, *p;
      int eplen, ptype;
      void *pval;
      unsigned int old_flags;
  
      if (!eckey_param2type(&ptype, &pval, &ec_key)) {
          ECerr(EC_F_ECKEY_PRIV_ENCODE, EC_R_DECODE_ERROR);
          return 0;
      }
  
      /* set the private key */
  
      /*
       * do not include the parameters in the SEC1 private key see PKCS#11
       * 12.11
       */
      old_flags = EC_KEY_get_enc_flags(&ec_key);
      EC_KEY_set_enc_flags(&ec_key, old_flags | EC_PKEY_NO_PARAMETERS);
  
      eplen = i2d_ECPrivateKey(&ec_key, NULL);
      if (!eplen) {
          ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
          return 0;
      }
      ep = OPENSSL_malloc(eplen);
      if (ep == NULL) {
          ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
          return 0;
      }
      p = ep;
      if (!i2d_ECPrivateKey(&ec_key, &p)) {
          OPENSSL_free(ep);
          ECerr(EC_F_ECKEY_PRIV_ENCODE, ERR_R_EC_LIB);
          return 0;
      }
  
      if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_X9_62_id_ecPublicKey), 0,
                           ptype, pval, ep, eplen)) {
          OPENSSL_free(ep);
          return 0;
      }
  
      return 1;
  }
  
  static int int_ec_size(const EVP_PKEY *pkey)
  {
      return ECDSA_size(pkey->pkey.ec);
  }
  
  static int ec_bits(const EVP_PKEY *pkey)
  {
      return EC_GROUP_order_bits(EC_KEY_get0_group(pkey->pkey.ec));
  }
  
  static int ec_security_bits(const EVP_PKEY *pkey)
  {
      int ecbits = ec_bits(pkey);
      if (ecbits >= 512)
          return 256;
      if (ecbits >= 384)
          return 192;
      if (ecbits >= 256)
          return 128;
      if (ecbits >= 224)
          return 112;
      if (ecbits >= 160)
          return 80;
      return ecbits / 2;
  }
  
  static int ec_missing_parameters(const EVP_PKEY *pkey)
  {
      if (pkey->pkey.ec == NULL || EC_KEY_get0_group(pkey->pkey.ec) == NULL)
          return 1;
      return 0;
  }
  
  static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
  {
      EC_GROUP *group = EC_GROUP_dup(EC_KEY_get0_group(from->pkey.ec));
  
      if (group == NULL)
          return 0;
      if (to->pkey.ec == NULL) {
          to->pkey.ec = EC_KEY_new();
          if (to->pkey.ec == NULL)
              goto err;
      }
      if (EC_KEY_set_group(to->pkey.ec, group) == 0)
          goto err;
      EC_GROUP_free(group);
      return 1;
   err:
      EC_GROUP_free(group);
      return 0;
  }
  
  static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
  {
      const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
          *group_b = EC_KEY_get0_group(b->pkey.ec);
      if (group_a == NULL || group_b == NULL)
          return -2;
      if (EC_GROUP_cmp(group_a, group_b, NULL))
          return 0;
      else
          return 1;
  }
  
  static void int_ec_free(EVP_PKEY *pkey)
  {
      EC_KEY_free(pkey->pkey.ec);
  }
  
  typedef enum {
      EC_KEY_PRINT_PRIVATE,
      EC_KEY_PRINT_PUBLIC,
      EC_KEY_PRINT_PARAM
  } ec_print_t;
  
  static int do_EC_KEY_print(BIO *bp, const EC_KEY *x, int off, ec_print_t ktype)
  {
      const char *ecstr;
      unsigned char *priv = NULL, *pub = NULL;
      size_t privlen = 0, publen = 0;
      int ret = 0;
      const EC_GROUP *group;
  
      if (x == NULL || (group = EC_KEY_get0_group(x)) == NULL) {
          ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
  
      if (ktype != EC_KEY_PRINT_PARAM && EC_KEY_get0_public_key(x) != NULL) {
          publen = EC_KEY_key2buf(x, EC_KEY_get_conv_form(x), &pub, NULL);
          if (publen == 0)
              goto err;
      }
  
      if (ktype == EC_KEY_PRINT_PRIVATE && EC_KEY_get0_private_key(x) != NULL) {
          privlen = EC_KEY_priv2buf(x, &priv);
          if (privlen == 0)
              goto err;
      }
  
      if (ktype == EC_KEY_PRINT_PRIVATE)
          ecstr = "Private-Key";
      else if (ktype == EC_KEY_PRINT_PUBLIC)
          ecstr = "Public-Key";
      else
          ecstr = "ECDSA-Parameters";
  
      if (!BIO_indent(bp, off, 128))
          goto err;
      if (BIO_printf(bp, "%s: (%d bit)\n", ecstr,
                     EC_GROUP_order_bits(group)) <= 0)
          goto err;
  
      if (privlen != 0) {
          if (BIO_printf(bp, "%*spriv:\n", off, "") <= 0)
              goto err;
          if (ASN1_buf_print(bp, priv, privlen, off + 4) == 0)
              goto err;
      }
  
      if (publen != 0) {
          if (BIO_printf(bp, "%*spub:\n", off, "") <= 0)
              goto err;
          if (ASN1_buf_print(bp, pub, publen, off + 4) == 0)
              goto err;
      }
  
      if (!ECPKParameters_print(bp, group, off))
          goto err;
      ret = 1;
   err:
      if (!ret)
          ECerr(EC_F_DO_EC_KEY_PRINT, ERR_R_EC_LIB);
      OPENSSL_clear_free(priv, privlen);
      OPENSSL_free(pub);
      return ret;
  }
  
  static int eckey_param_decode(EVP_PKEY *pkey,
                                const unsigned char **pder, int derlen)
  {
      EC_KEY *eckey;
  
      if ((eckey = d2i_ECParameters(NULL, pder, derlen)) == NULL) {
          ECerr(EC_F_ECKEY_PARAM_DECODE, ERR_R_EC_LIB);
          return 0;
      }
      EVP_PKEY_assign_EC_KEY(pkey, eckey);
      return 1;
  }
  
  static int eckey_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
  {
      return i2d_ECParameters(pkey->pkey.ec, pder);
  }
  
  static int eckey_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                               ASN1_PCTX *ctx)
  {
      return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PARAM);
  }
  
  static int eckey_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                             ASN1_PCTX *ctx)
  {
      return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PUBLIC);
  }
  
  static int eckey_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                              ASN1_PCTX *ctx)
  {
      return do_EC_KEY_print(bp, pkey->pkey.ec, indent, EC_KEY_PRINT_PRIVATE);
  }
  
  static int old_ec_priv_decode(EVP_PKEY *pkey,
                                const unsigned char **pder, int derlen)
  {
      EC_KEY *ec;
  
      if ((ec = d2i_ECPrivateKey(NULL, pder, derlen)) == NULL) {
          ECerr(EC_F_OLD_EC_PRIV_DECODE, EC_R_DECODE_ERROR);
          return 0;
      }
      EVP_PKEY_assign_EC_KEY(pkey, ec);
      return 1;
  }
  
  static int old_ec_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
  {
      return i2d_ECPrivateKey(pkey->pkey.ec, pder);
  }
  
  static int ec_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
  {
      switch (op) {
      case ASN1_PKEY_CTRL_PKCS7_SIGN:
          if (arg1 == 0) {
              int snid, hnid;
              X509_ALGOR *alg1, *alg2;
              PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
              if (alg1 == NULL || alg1->algorithm == NULL)
                  return -1;
              hnid = OBJ_obj2nid(alg1->algorithm);
              if (hnid == NID_undef)
                  return -1;
              if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
                  return -1;
              X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
          }
          return 1;
  #ifndef OPENSSL_NO_CMS
      case ASN1_PKEY_CTRL_CMS_SIGN:
          if (arg1 == 0) {
              int snid, hnid;
              X509_ALGOR *alg1, *alg2;
              CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
              if (alg1 == NULL || alg1->algorithm == NULL)
                  return -1;
              hnid = OBJ_obj2nid(alg1->algorithm);
              if (hnid == NID_undef)
                  return -1;
              if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
                  return -1;
              X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
          }
          return 1;
  
      case ASN1_PKEY_CTRL_CMS_ENVELOPE:
          if (arg1 == 1)
              return ecdh_cms_decrypt(arg2);
          else if (arg1 == 0)
              return ecdh_cms_encrypt(arg2);
          return -2;
  
      case ASN1_PKEY_CTRL_CMS_RI_TYPE:
          *(int *)arg2 = CMS_RECIPINFO_AGREE;
          return 1;
  #endif
  
      case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
          if (EVP_PKEY_id(pkey) == EVP_PKEY_SM2) {
              /* For SM2, the only valid digest-alg is SM3 */
              *(int *)arg2 = NID_sm3;
          } else {
              *(int *)arg2 = NID_sha256;
          }
          return 1;
  
      case ASN1_PKEY_CTRL_SET1_TLS_ENCPT:
          return EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(pkey), arg2, arg1, NULL);
  
      case ASN1_PKEY_CTRL_GET1_TLS_ENCPT:
          return EC_KEY_key2buf(EVP_PKEY_get0_EC_KEY(pkey),
                                POINT_CONVERSION_UNCOMPRESSED, arg2, NULL);
  
      default:
          return -2;
  
      }
  
  }
  
  static int ec_pkey_check(const EVP_PKEY *pkey)
  {
      EC_KEY *eckey = pkey->pkey.ec;
  
      /* stay consistent to what EVP_PKEY_check demands */
      if (eckey->priv_key == NULL) {
          ECerr(EC_F_EC_PKEY_CHECK, EC_R_MISSING_PRIVATE_KEY);
          return 0;
      }
  
      return EC_KEY_check_key(eckey);
  }
  
  static int ec_pkey_public_check(const EVP_PKEY *pkey)
  {
      EC_KEY *eckey = pkey->pkey.ec;
  
      /*
       * Note: it unnecessary to check eckey->pub_key here since
       * it will be checked in EC_KEY_check_key(). In fact, the
       * EC_KEY_check_key() mainly checks the public key, and checks
       * the private key optionally (only if there is one). So if
       * someone passes a whole EC key (public + private), this
       * will also work...
       */
  
      return EC_KEY_check_key(eckey);
  }
  
  static int ec_pkey_param_check(const EVP_PKEY *pkey)
  {
      EC_KEY *eckey = pkey->pkey.ec;
  
      /* stay consistent to what EVP_PKEY_check demands */
      if (eckey->group == NULL) {
          ECerr(EC_F_EC_PKEY_PARAM_CHECK, EC_R_MISSING_PARAMETERS);
          return 0;
      }
  
      return EC_GROUP_check(eckey->group, NULL);
  }
  
  const EVP_PKEY_ASN1_METHOD eckey_asn1_meth = {
      EVP_PKEY_EC,
      EVP_PKEY_EC,
      0,
      "EC",
      "OpenSSL EC algorithm",
  
      eckey_pub_decode,
      eckey_pub_encode,
      eckey_pub_cmp,
      eckey_pub_print,
  
      eckey_priv_decode,
      eckey_priv_encode,
      eckey_priv_print,
  
      int_ec_size,
      ec_bits,
      ec_security_bits,
  
      eckey_param_decode,
      eckey_param_encode,
      ec_missing_parameters,
      ec_copy_parameters,
      ec_cmp_parameters,
      eckey_param_print,
      0,
  
      int_ec_free,
      ec_pkey_ctrl,
      old_ec_priv_decode,
      old_ec_priv_encode,
  
      0, 0, 0,
  
      ec_pkey_check,
      ec_pkey_public_check,
      ec_pkey_param_check
  };
  
  #if !defined(OPENSSL_NO_SM2)
  const EVP_PKEY_ASN1_METHOD sm2_asn1_meth = {
     EVP_PKEY_SM2,
     EVP_PKEY_EC,
     ASN1_PKEY_ALIAS
  };
  #endif
  
  int EC_KEY_print(BIO *bp, const EC_KEY *x, int off)
  {
      int private = EC_KEY_get0_private_key(x) != NULL;
  
      return do_EC_KEY_print(bp, x, off,
                  private ? EC_KEY_PRINT_PRIVATE : EC_KEY_PRINT_PUBLIC);
  }
  
  int ECParameters_print(BIO *bp, const EC_KEY *x)
  {
      return do_EC_KEY_print(bp, x, 4, EC_KEY_PRINT_PARAM);
  }
  
  #ifndef OPENSSL_NO_CMS
  
  static int ecdh_cms_set_peerkey(EVP_PKEY_CTX *pctx,
                                  X509_ALGOR *alg, ASN1_BIT_STRING *pubkey)
  {
      const ASN1_OBJECT *aoid;
      int atype;
      const void *aval;
      int rv = 0;
      EVP_PKEY *pkpeer = NULL;
      EC_KEY *ecpeer = NULL;
      const unsigned char *p;
      int plen;
      X509_ALGOR_get0(&aoid, &atype, &aval, alg);
      if (OBJ_obj2nid(aoid) != NID_X9_62_id_ecPublicKey)
          goto err;
      /* If absent parameters get group from main key */
      if (atype == V_ASN1_UNDEF || atype == V_ASN1_NULL) {
          const EC_GROUP *grp;
          EVP_PKEY *pk;
          pk = EVP_PKEY_CTX_get0_pkey(pctx);
          if (!pk)
              goto err;
          grp = EC_KEY_get0_group(pk->pkey.ec);
          ecpeer = EC_KEY_new();
          if (ecpeer == NULL)
              goto err;
          if (!EC_KEY_set_group(ecpeer, grp))
              goto err;
      } else {
          ecpeer = eckey_type2param(atype, aval);
          if (!ecpeer)
              goto err;
      }
      /* We have parameters now set public key */
      plen = ASN1_STRING_length(pubkey);
      p = ASN1_STRING_get0_data(pubkey);
      if (!p || !plen)
          goto err;
      if (!o2i_ECPublicKey(&ecpeer, &p, plen))
          goto err;
      pkpeer = EVP_PKEY_new();
      if (pkpeer == NULL)
          goto err;
      EVP_PKEY_set1_EC_KEY(pkpeer, ecpeer);
      if (EVP_PKEY_derive_set_peer(pctx, pkpeer) > 0)
          rv = 1;
   err:
      EC_KEY_free(ecpeer);
      EVP_PKEY_free(pkpeer);
      return rv;
  }
  
  /* Set KDF parameters based on KDF NID */
  static int ecdh_cms_set_kdf_param(EVP_PKEY_CTX *pctx, int eckdf_nid)
  {
      int kdf_nid, kdfmd_nid, cofactor;
      const EVP_MD *kdf_md;
      if (eckdf_nid == NID_undef)
          return 0;
  
      /* Lookup KDF type, cofactor mode and digest */
      if (!OBJ_find_sigid_algs(eckdf_nid, &kdfmd_nid, &kdf_nid))
          return 0;
  
      if (kdf_nid == NID_dh_std_kdf)
          cofactor = 0;
      else if (kdf_nid == NID_dh_cofactor_kdf)
          cofactor = 1;
      else
          return 0;
  
      if (EVP_PKEY_CTX_set_ecdh_cofactor_mode(pctx, cofactor) <= 0)
          return 0;
  
      if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, EVP_PKEY_ECDH_KDF_X9_63) <= 0)
          return 0;
  
      kdf_md = EVP_get_digestbynid(kdfmd_nid);
      if (!kdf_md)
          return 0;
  
      if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
          return 0;
      return 1;
  }
  
  static int ecdh_cms_set_shared_info(EVP_PKEY_CTX *pctx, CMS_RecipientInfo *ri)
  {
      int rv = 0;
  
      X509_ALGOR *alg, *kekalg = NULL;
      ASN1_OCTET_STRING *ukm;
      const unsigned char *p;
      unsigned char *der = NULL;
      int plen, keylen;
      const EVP_CIPHER *kekcipher;
      EVP_CIPHER_CTX *kekctx;
  
      if (!CMS_RecipientInfo_kari_get0_alg(ri, &alg, &ukm))
          return 0;
  
      if (!ecdh_cms_set_kdf_param(pctx, OBJ_obj2nid(alg->algorithm))) {
          ECerr(EC_F_ECDH_CMS_SET_SHARED_INFO, EC_R_KDF_PARAMETER_ERROR);
          return 0;
      }
  
      if (alg->parameter->type != V_ASN1_SEQUENCE)
          return 0;
  
      p = alg->parameter->value.sequence->data;
      plen = alg->parameter->value.sequence->length;
      kekalg = d2i_X509_ALGOR(NULL, &p, plen);
      if (!kekalg)
          goto err;
      kekctx = CMS_RecipientInfo_kari_get0_ctx(ri);
      if (!kekctx)
          goto err;
      kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
      if (!kekcipher || EVP_CIPHER_mode(kekcipher) != EVP_CIPH_WRAP_MODE)
          goto err;
      if (!EVP_EncryptInit_ex(kekctx, kekcipher, NULL, NULL, NULL))
          goto err;
      if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0)
          goto err;
  
      keylen = EVP_CIPHER_CTX_key_length(kekctx);
      if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
          goto err;
  
      plen = CMS_SharedInfo_encode(&der, kekalg, ukm, keylen);
  
      if (!plen)
          goto err;
  
      if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, der, plen) <= 0)
          goto err;
      der = NULL;
  
      rv = 1;
   err:
      X509_ALGOR_free(kekalg);
      OPENSSL_free(der);
      return rv;
  }
  
  static int ecdh_cms_decrypt(CMS_RecipientInfo *ri)
  {
      EVP_PKEY_CTX *pctx;
      pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
      if (!pctx)
          return 0;
      /* See if we need to set peer key */
      if (!EVP_PKEY_CTX_get0_peerkey(pctx)) {
          X509_ALGOR *alg;
          ASN1_BIT_STRING *pubkey;
          if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &alg, &pubkey,
                                                   NULL, NULL, NULL))
              return 0;
          if (!alg || !pubkey)
              return 0;
          if (!ecdh_cms_set_peerkey(pctx, alg, pubkey)) {
              ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_PEER_KEY_ERROR);
              return 0;
          }
      }
      /* Set ECDH derivation parameters and initialise unwrap context */
      if (!ecdh_cms_set_shared_info(pctx, ri)) {
          ECerr(EC_F_ECDH_CMS_DECRYPT, EC_R_SHARED_INFO_ERROR);
          return 0;
      }
      return 1;
  }
  
  static int ecdh_cms_encrypt(CMS_RecipientInfo *ri)
  {
      EVP_PKEY_CTX *pctx;
      EVP_PKEY *pkey;
      EVP_CIPHER_CTX *ctx;
      int keylen;
      X509_ALGOR *talg, *wrap_alg = NULL;
      const ASN1_OBJECT *aoid;
      ASN1_BIT_STRING *pubkey;
      ASN1_STRING *wrap_str;
      ASN1_OCTET_STRING *ukm;
      unsigned char *penc = NULL;
      int penclen;
      int rv = 0;
      int ecdh_nid, kdf_type, kdf_nid, wrap_nid;
      const EVP_MD *kdf_md;
      pctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
      if (!pctx)
          return 0;
      /* Get ephemeral key */
      pkey = EVP_PKEY_CTX_get0_pkey(pctx);
      if (!CMS_RecipientInfo_kari_get0_orig_id(ri, &talg, &pubkey,
                                               NULL, NULL, NULL))
          goto err;
      X509_ALGOR_get0(&aoid, NULL, NULL, talg);
      /* Is everything uninitialised? */
      if (aoid == OBJ_nid2obj(NID_undef)) {
  
          EC_KEY *eckey = pkey->pkey.ec;
          /* Set the key */
          unsigned char *p;
  
          penclen = i2o_ECPublicKey(eckey, NULL);
          if (penclen <= 0)
              goto err;
          penc = OPENSSL_malloc(penclen);
          if (penc == NULL)
              goto err;
          p = penc;
          penclen = i2o_ECPublicKey(eckey, &p);
          if (penclen <= 0)
              goto err;
          ASN1_STRING_set0(pubkey, penc, penclen);
          pubkey->flags &= ~(ASN1_STRING_FLAG_BITS_LEFT | 0x07);
          pubkey->flags |= ASN1_STRING_FLAG_BITS_LEFT;
  
          penc = NULL;
          X509_ALGOR_set0(talg, OBJ_nid2obj(NID_X9_62_id_ecPublicKey),
                          V_ASN1_UNDEF, NULL);
      }
  
      /* See if custom parameters set */
      kdf_type = EVP_PKEY_CTX_get_ecdh_kdf_type(pctx);
      if (kdf_type <= 0)
          goto err;
      if (!EVP_PKEY_CTX_get_ecdh_kdf_md(pctx, &kdf_md))
          goto err;
      ecdh_nid = EVP_PKEY_CTX_get_ecdh_cofactor_mode(pctx);
      if (ecdh_nid < 0)
          goto err;
      else if (ecdh_nid == 0)
          ecdh_nid = NID_dh_std_kdf;
      else if (ecdh_nid == 1)
          ecdh_nid = NID_dh_cofactor_kdf;
  
      if (kdf_type == EVP_PKEY_ECDH_KDF_NONE) {
          kdf_type = EVP_PKEY_ECDH_KDF_X9_63;
          if (EVP_PKEY_CTX_set_ecdh_kdf_type(pctx, kdf_type) <= 0)
              goto err;
      } else
          /* Unknown KDF */
          goto err;
      if (kdf_md == NULL) {
          /* Fixme later for better MD */
          kdf_md = EVP_sha1();
          if (EVP_PKEY_CTX_set_ecdh_kdf_md(pctx, kdf_md) <= 0)
              goto err;
      }
  
      if (!CMS_RecipientInfo_kari_get0_alg(ri, &talg, &ukm))
          goto err;
  
      /* Lookup NID for KDF+cofactor+digest */
  
      if (!OBJ_find_sigid_by_algs(&kdf_nid, EVP_MD_type(kdf_md), ecdh_nid))
          goto err;
      /* Get wrap NID */
      ctx = CMS_RecipientInfo_kari_get0_ctx(ri);
      wrap_nid = EVP_CIPHER_CTX_type(ctx);
      keylen = EVP_CIPHER_CTX_key_length(ctx);
  
      /* Package wrap algorithm in an AlgorithmIdentifier */
  
      wrap_alg = X509_ALGOR_new();
      if (wrap_alg == NULL)
          goto err;
      wrap_alg->algorithm = OBJ_nid2obj(wrap_nid);
      wrap_alg->parameter = ASN1_TYPE_new();
      if (wrap_alg->parameter == NULL)
          goto err;
      if (EVP_CIPHER_param_to_asn1(ctx, wrap_alg->parameter) <= 0)
          goto err;
      if (ASN1_TYPE_get(wrap_alg->parameter) == NID_undef) {
          ASN1_TYPE_free(wrap_alg->parameter);
          wrap_alg->parameter = NULL;
      }
  
      if (EVP_PKEY_CTX_set_ecdh_kdf_outlen(pctx, keylen) <= 0)
          goto err;
  
      penclen = CMS_SharedInfo_encode(&penc, wrap_alg, ukm, keylen);
  
      if (!penclen)
          goto err;
  
      if (EVP_PKEY_CTX_set0_ecdh_kdf_ukm(pctx, penc, penclen) <= 0)
          goto err;
      penc = NULL;
  
      /*
       * Now need to wrap encoding of wrap AlgorithmIdentifier into parameter
       * of another AlgorithmIdentifier.
       */
      penclen = i2d_X509_ALGOR(wrap_alg, &penc);
      if (!penc || !penclen)
          goto err;
      wrap_str = ASN1_STRING_new();
      if (wrap_str == NULL)
          goto err;
      ASN1_STRING_set0(wrap_str, penc, penclen);
      penc = NULL;
      X509_ALGOR_set0(talg, OBJ_nid2obj(kdf_nid), V_ASN1_SEQUENCE, wrap_str);
  
      rv = 1;
  
   err:
      OPENSSL_free(penc);
      X509_ALGOR_free(wrap_alg);
      return rv;
  }
  
  #endif
  