text: /*
   * Copyright 2002-2019 The Opentls Project Authors. All Rights Reserved.
   * Copyright (c) 2002, Oracle and/or its affiliates. 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.opentls.org/source/license.html
   */
  
  #include "internal/cryptlib.h"
  #include <string.h>
  #include "ec_local.h"
  #include "internal/refcount.h"
  #include <opentls/err.h>
  #include <opentls/engine.h>
  
  #ifndef FIPS_MODE
  EC_KEY *EC_KEY_new(void)
  {
      return ec_key_new_method_int(NULL, NULL);
  }
  #endif
  
  EC_KEY *EC_KEY_new_ex(OPENtls_CTX *ctx)
  {
      return ec_key_new_method_int(ctx, NULL);
  }
  
  EC_KEY *EC_KEY_new_by_curve_name_ex(OPENtls_CTX *ctx, int nid)
  {
      EC_KEY *ret = EC_KEY_new_ex(ctx);
      if (ret == NULL)
          return NULL;
      ret->group = EC_GROUP_new_by_curve_name_ex(ctx, nid);
      if (ret->group == NULL) {
          EC_KEY_free(ret);
          return NULL;
      }
      if (ret->meth->set_group != NULL
          && ret->meth->set_group(ret, ret->group) == 0) {
          EC_KEY_free(ret);
          return NULL;
      }
      return ret;
  }
  
  #ifndef FIPS_MODE
  EC_KEY *EC_KEY_new_by_curve_name(int nid)
  {
      return EC_KEY_new_by_curve_name_ex(NULL, nid);
  }
  #endif
  
  void EC_KEY_free(EC_KEY *r)
  {
      int i;
  
      if (r == NULL)
          return;
  
      CRYPTO_DOWN_REF(&r->references, &i, r->lock);
      REF_PRINT_COUNT("EC_KEY", r);
      if (i > 0)
          return;
      REF_ASSERT_ISNT(i < 0);
  
      if (r->meth != NULL && r->meth->finish != NULL)
          r->meth->finish(r);
  
  #if !defined(OPENtls_NO_ENGINE) && !defined(FIPS_MODE)
      ENGINE_finish(r->engine);
  #endif
  
      if (r->group && r->group->meth->keyfinish)
          r->group->meth->keyfinish(r);
  
  #ifndef FIPS_MODE
      CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data);
  #endif
      CRYPTO_THREAD_lock_free(r->lock);
      EC_GROUP_free(r->group);
      EC_POINT_free(r->pub_key);
      BN_clear_free(r->priv_key);
  
      OPENtls_clear_free((void *)r, sizeof(EC_KEY));
  }
  
  EC_KEY *EC_KEY_copy(EC_KEY *dest, const EC_KEY *src)
  {
      if (dest == NULL || src == NULL) {
          ECerr(EC_F_EC_KEY_COPY, ERR_R_PASSED_NULL_PARAMETER);
          return NULL;
      }
      if (src->meth != dest->meth) {
          if (dest->meth->finish != NULL)
              dest->meth->finish(dest);
          if (dest->group && dest->group->meth->keyfinish)
              dest->group->meth->keyfinish(dest);
  #if !defined(OPENtls_NO_ENGINE) && !defined(FIPS_MODE)
          if (ENGINE_finish(dest->engine) == 0)
              return 0;
          dest->engine = NULL;
  #endif
      }
      dest->libctx = src->libctx;
      /* copy the parameters */
      if (src->group != NULL) {
          const EC_METHOD *meth = EC_GROUP_method_of(src->group);
          /* clear the old group */
          EC_GROUP_free(dest->group);
          dest->group = EC_GROUP_new_ex(src->libctx, meth);
          if (dest->group == NULL)
              return NULL;
          if (!EC_GROUP_copy(dest->group, src->group))
              return NULL;
  
          /*  copy the public key */
          if (src->pub_key != NULL) {
              EC_POINT_free(dest->pub_key);
              dest->pub_key = EC_POINT_new(src->group);
              if (dest->pub_key == NULL)
                  return NULL;
              if (!EC_POINT_copy(dest->pub_key, src->pub_key))
                  return NULL;
          }
          /* copy the private key */
          if (src->priv_key != NULL) {
              if (dest->priv_key == NULL) {
                  dest->priv_key = BN_new();
                  if (dest->priv_key == NULL)
                      return NULL;
              }
              if (!BN_copy(dest->priv_key, src->priv_key))
                  return NULL;
              if (src->group->meth->keycopy
                  && src->group->meth->keycopy(dest, src) == 0)
                  return NULL;
          }
      }
  
  
      /* copy the rest */
      dest->enc_flag = src->enc_flag;
      dest->conv_form = src->conv_form;
      dest->version = src->version;
      dest->flags = src->flags;
  #ifndef FIPS_MODE
      if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY,
                              &dest->ex_data, &src->ex_data))
          return NULL;
  #endif
  
      if (src->meth != dest->meth) {
  #if !defined(OPENtls_NO_ENGINE) && !defined(FIPS_MODE)
          if (src->engine != NULL && ENGINE_init(src->engine) == 0)
              return NULL;
          dest->engine = src->engine;
  #endif
          dest->meth = src->meth;
      }
  
      if (src->meth->copy != NULL && src->meth->copy(dest, src) == 0)
          return NULL;
  
      return dest;
  }
  
  EC_KEY *EC_KEY_dup(const EC_KEY *ec_key)
  {
      EC_KEY *ret = ec_key_new_method_int(ec_key->libctx, ec_key->engine);
  
      if (ret == NULL)
          return NULL;
  
      if (EC_KEY_copy(ret, ec_key) == NULL) {
          EC_KEY_free(ret);
          return NULL;
      }
      return ret;
  }
  
  int EC_KEY_up_ref(EC_KEY *r)
  {
      int i;
  
      if (CRYPTO_UP_REF(&r->references, &i, r->lock) <= 0)
          return 0;
  
      REF_PRINT_COUNT("EC_KEY", r);
      REF_ASSERT_ISNT(i < 2);
      return ((i > 1) ? 1 : 0);
  }
  
  ENGINE *EC_KEY_get0_engine(const EC_KEY *eckey)
  {
      return eckey->engine;
  }
  
  int EC_KEY_generate_key(EC_KEY *eckey)
  {
      if (eckey == NULL || eckey->group == NULL) {
          ECerr(EC_F_EC_KEY_GENERATE_KEY, ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
      if (eckey->meth->keygen != NULL)
          return eckey->meth->keygen(eckey);
      ECerr(EC_F_EC_KEY_GENERATE_KEY, EC_R_OPERATION_NOT_SUPPORTED);
      return 0;
  }
  
  int otls_ec_key_gen(EC_KEY *eckey)
  {
      return eckey->group->meth->keygen(eckey);
  }
  
  /*
   * ECC Key generation.
   * See SP800-56AR3 5.6.1.2.2 "Key Pair Generation by Testing Candidates"
   *
   * Params:
   *     eckey An EC key object that contains domain params. The generated keypair
   *           is stored in this object.
   * Returns 1 if the keypair was generated or 0 otherwise.
   */
  int ec_key_simple_generate_key(EC_KEY *eckey)
  {
      int ok = 0;
      BIGNUM *priv_key = NULL;
      const BIGNUM *order = NULL;
      EC_POINT *pub_key = NULL;
      const EC_GROUP *group = eckey->group;
      BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx);
  
      if (ctx == NULL)
          goto err;
  
      if (eckey->priv_key == NULL) {
          priv_key = BN_secure_new();
          if (priv_key == NULL)
              goto err;
      } else
          priv_key = eckey->priv_key;
  
      /*
       * Steps (1-2): Check domain parameters and security strength.
       * These steps must be done by the user. This would need to be
       * stated in the security policy.
       */
  
      order = EC_GROUP_get0_order(group);
      if (order == NULL)
          goto err;
  
      /*
       * Steps (3-7): priv_key = DRBG_RAND(order_n_bits) (range [1, n-1]).
       * Although this is slightly different from the standard, it is effectively
       * equivalent as it gives an unbiased result ranging from 1..n-1. It is also
       * faster as the standard needs to retry more often. Also doing
       * 1 + rand[0..n-2] would effect the way that tests feed dummy entropy into
       * rand so the simpler backward compatible method has been used here.
       */
      do
          if (!BN_priv_rand_range_ex(priv_key, order, ctx))
              goto err;
      while (BN_is_zero(priv_key)) ;
  
      if (eckey->pub_key == NULL) {
          pub_key = EC_POINT_new(group);
          if (pub_key == NULL)
              goto err;
      } else
          pub_key = eckey->pub_key;
  
      /* Step (8) : pub_key = priv_key * G (where G is a point on the curve) */
      if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx))
          goto err;
  
      eckey->priv_key = priv_key;
      eckey->pub_key = pub_key;
      priv_key = NULL;
      pub_key = NULL;
  
      ok = 1;
  
  err:
      /* Step (9): If there is an error return an invalid keypair. */
      if (!ok) {
          BN_clear(eckey->priv_key);
          if (eckey->pub_key != NULL)
              EC_POINT_set_to_infinity(group, eckey->pub_key);
      }
  
      EC_POINT_free(pub_key);
      BN_clear_free(priv_key);
      BN_CTX_free(ctx);
      return ok;
  }
  
  int ec_key_simple_generate_public_key(EC_KEY *eckey)
  {
      /*
       * See SP800-56AR3 5.6.1.2.2: Step (8)
       * pub_key = priv_key * G (where G is a point on the curve)
       */
      return EC_POINT_mul(eckey->group, eckey->pub_key, eckey->priv_key, NULL,
                          NULL, NULL);
  }
  
  int EC_KEY_check_key(const EC_KEY *eckey)
  {
      if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
          ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
  
      if (eckey->group->meth->keycheck == NULL) {
          ECerr(EC_F_EC_KEY_CHECK_KEY, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
          return 0;
      }
  
      return eckey->group->meth->keycheck(eckey);
  }
  
  /*
   * Check the range of the EC public key.
   * See SP800-56A R3 Section 5.6.2.3.3 (Part 2)
   * i.e.
   *  - If q = odd prime p: Verify that xQ and yQ are integers in the
   *    interval[0, p - 1], OR
   *  - If q = 2m: Verify that xQ and yQ are bit strings of length m bits.
   * Returns 1 if the public key has a valid range, otherwise it returns 0.
   */
  static int ec_key_public_range_check(BN_CTX *ctx, const EC_KEY *key)
  {
      int ret = 0;
      BIGNUM *x, *y;
  
      BN_CTX_start(ctx);
      x = BN_CTX_get(ctx);
      y = BN_CTX_get(ctx);
      if (y == NULL)
          goto err;
  
      if (!EC_POINT_get_affine_coordinates(key->group, key->pub_key, x, y, ctx))
          goto err;
  
      if (EC_METHOD_get_field_type(key->group->meth) == NID_X9_62_prime_field) {
          if (BN_is_negative(x)
              || BN_cmp(x, key->group->field) >= 0
              || BN_is_negative(y)
              || BN_cmp(y, key->group->field) >= 0) {
              goto err;
          }
      } else {
          int m = EC_GROUP_get_degree(key->group);
          if (BN_num_bits(x) > m || BN_num_bits(y) > m) {
              goto err;
          }
      }
      ret = 1;
  err:
      BN_CTX_end(ctx);
      return ret;
  }
  
  /*
   * ECC Key validation as specified in SP800-56A R3.
   *    Section 5.6.2.3.3 ECC Full Public-Key Validation
   *    Section 5.6.2.1.2 Owner Assurance of Private-Key Validity
   *    Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
   * NOTES:
   *    Before calling this method in fips mode, there should be an assurance that
   *    an approved elliptic-curve group is used.
   * Returns 1 if the key is valid, otherwise it returns 0.
   */
  int ec_key_simple_check_key(const EC_KEY *eckey)
  {
      int ok = 0;
      BN_CTX *ctx = NULL;
      const BIGNUM *order = NULL;
      EC_POINT *point = NULL;
  
      if (eckey == NULL || eckey->group == NULL || eckey->pub_key == NULL) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
  
      /* 5.6.2.3.3 (Step 1): Q != infinity */
      if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key)) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_AT_INFINITY);
          goto err;
      }
  
      if ((ctx = BN_CTX_new_ex(eckey->libctx)) == NULL)
          goto err;
  
      if ((point = EC_POINT_new(eckey->group)) == NULL)
          goto err;
  
      /* 5.6.2.3.3 (Step 2) Test if the public key is in range */
      if (!ec_key_public_range_check(ctx, eckey)) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_COORDINATES_OUT_OF_RANGE);
          goto err;
      }
  
      /* 5.6.2.3.3 (Step 3) is the pub_key on the elliptic curve */
      if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_POINT_IS_NOT_ON_CURVE);
          goto err;
      }
  
      order = eckey->group->order;
      if (BN_is_zero(order)) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_GROUP_ORDER);
          goto err;
      }
      /* 5.6.2.3.3 (Step 4) : pub_key * order is the point at infinity. */
      if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
          goto err;
      }
      if (!EC_POINT_is_at_infinity(eckey->group, point)) {
          ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
          goto err;
      }
  
      if (eckey->priv_key != NULL) {
          /*
           * 5.6.2.1.2 Owner Assurance of Private-Key Validity
           * The private key is in the range [1, order-1]
           */
          if (BN_cmp(eckey->priv_key, BN_value_one()) < 0
                  || BN_cmp(eckey->priv_key, order) >= 0) {
              ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_WRONG_ORDER);
              goto err;
          }
          /*
           * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency (b)
           * Check if generator * priv_key = pub_key
           */
          if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
                            NULL, NULL, ctx)) {
              ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, ERR_R_EC_LIB);
              goto err;
          }
          if (EC_POINT_cmp(eckey->group, point, eckey->pub_key, ctx) != 0) {
              ECerr(EC_F_EC_KEY_SIMPLE_CHECK_KEY, EC_R_INVALID_PRIVATE_KEY);
              goto err;
          }
      }
      ok = 1;
   err:
      BN_CTX_free(ctx);
      EC_POINT_free(point);
      return ok;
  }
  
  int EC_KEY_set_public_key_affine_coordinates(EC_KEY *key, BIGNUM *x,
                                               BIGNUM *y)
  {
      BN_CTX *ctx = NULL;
      BIGNUM *tx, *ty;
      EC_POINT *point = NULL;
      int ok = 0;
  
      if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
          ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
                ERR_R_PASSED_NULL_PARAMETER);
          return 0;
      }
      ctx = BN_CTX_new_ex(key->libctx);
      if (ctx == NULL)
          return 0;
  
      BN_CTX_start(ctx);
      point = EC_POINT_new(key->group);
  
      if (point == NULL)
          goto err;
  
      tx = BN_CTX_get(ctx);
      ty = BN_CTX_get(ctx);
      if (ty == NULL)
          goto err;
  
      if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx))
          goto err;
      if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx))
          goto err;
  
      /*
       * Check if retrieved coordinates match originals. The range check is done
       * inside EC_KEY_check_key().
       */
      if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
          ECerr(EC_F_EC_KEY_SET_PUBLIC_KEY_AFFINE_COORDINATES,
                EC_R_COORDINATES_OUT_OF_RANGE);
          goto err;
      }
  
      if (!EC_KEY_set_public_key(key, point))
          goto err;
  
      if (EC_KEY_check_key(key) == 0)
          goto err;
  
      ok = 1;
  
   err:
      BN_CTX_end(ctx);
      BN_CTX_free(ctx);
      EC_POINT_free(point);
      return ok;
  
  }
  
  const EC_GROUP *EC_KEY_get0_group(const EC_KEY *key)
  {
      return key->group;
  }
  
  int EC_KEY_set_group(EC_KEY *key, const EC_GROUP *group)
  {
      if (key->meth->set_group != NULL && key->meth->set_group(key, group) == 0)
          return 0;
      EC_GROUP_free(key->group);
      key->group = EC_GROUP_dup(group);
      return (key->group == NULL) ? 0 : 1;
  }
  
  const BIGNUM *EC_KEY_get0_private_key(const EC_KEY *key)
  {
      return key->priv_key;
  }
  
  int EC_KEY_set_private_key(EC_KEY *key, const BIGNUM *priv_key)
  {
      if (key->group == NULL || key->group->meth == NULL)
          return 0;
      if (key->group->meth->set_private != NULL
          && key->group->meth->set_private(key, priv_key) == 0)
          return 0;
      if (key->meth->set_private != NULL
          && key->meth->set_private(key, priv_key) == 0)
          return 0;
      BN_clear_free(key->priv_key);
      key->priv_key = BN_dup(priv_key);
      return (key->priv_key == NULL) ? 0 : 1;
  }
  
  const EC_POINT *EC_KEY_get0_public_key(const EC_KEY *key)
  {
      return key->pub_key;
  }
  
  int EC_KEY_set_public_key(EC_KEY *key, const EC_POINT *pub_key)
  {
      if (key->meth->set_public != NULL
          && key->meth->set_public(key, pub_key) == 0)
          return 0;
      EC_POINT_free(key->pub_key);
      key->pub_key = EC_POINT_dup(pub_key, key->group);
      return (key->pub_key == NULL) ? 0 : 1;
  }
  
  unsigned int EC_KEY_get_enc_flags(const EC_KEY *key)
  {
      return key->enc_flag;
  }
  
  void EC_KEY_set_enc_flags(EC_KEY *key, unsigned int flags)
  {
      key->enc_flag = flags;
  }
  
  point_conversion_form_t EC_KEY_get_conv_form(const EC_KEY *key)
  {
      return key->conv_form;
  }
  
  void EC_KEY_set_conv_form(EC_KEY *key, point_conversion_form_t cform)
  {
      key->conv_form = cform;
      if (key->group != NULL)
          EC_GROUP_set_point_conversion_form(key->group, cform);
  }
  
  void EC_KEY_set_asn1_flag(EC_KEY *key, int flag)
  {
      if (key->group != NULL)
          EC_GROUP_set_asn1_flag(key->group, flag);
  }
  
  int EC_KEY_precompute_mult(EC_KEY *key, BN_CTX *ctx)
  {
      if (key->group == NULL)
          return 0;
      return EC_GROUP_precompute_mult(key->group, ctx);
  }
  
  int EC_KEY_get_flags(const EC_KEY *key)
  {
      return key->flags;
  }
  
  void EC_KEY_set_flags(EC_KEY *key, int flags)
  {
      key->flags |= flags;
  }
  
  void EC_KEY_clear_flags(EC_KEY *key, int flags)
  {
      key->flags &= ~flags;
  }
  
  size_t EC_KEY_key2buf(const EC_KEY *key, point_conversion_form_t form,
                          unsigned char **pbuf, BN_CTX *ctx)
  {
      if (key == NULL || key->pub_key == NULL || key->group == NULL)
          return 0;
      return EC_POINT_point2buf(key->group, key->pub_key, form, pbuf, ctx);
  }
  
  int EC_KEY_oct2key(EC_KEY *key, const unsigned char *buf, size_t len,
                     BN_CTX *ctx)
  {
      if (key == NULL || key->group == NULL)
          return 0;
      if (key->pub_key == NULL)
          key->pub_key = EC_POINT_new(key->group);
      if (key->pub_key == NULL)
          return 0;
      if (EC_POINT_oct2point(key->group, key->pub_key, buf, len, ctx) == 0)
          return 0;
      /*
       * Save the point conversion form.
       * For non-custom curves the first octet of the buffer (excluding
       * the last significant bit) contains the point conversion form.
       * EC_POINT_oct2point() has already performed sanity checking of
       * the buffer so we know it is valid.
       */
      if ((key->group->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0)
          key->conv_form = (point_conversion_form_t)(buf[0] & ~0x01);
      return 1;
  }
  
  size_t EC_KEY_priv2oct(const EC_KEY *eckey,
                         unsigned char *buf, size_t len)
  {
      if (eckey->group == NULL || eckey->group->meth == NULL)
          return 0;
      if (eckey->group->meth->priv2oct == NULL) {
          ECerr(EC_F_EC_KEY_PRIV2OCT, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
          return 0;
      }
  
      return eckey->group->meth->priv2oct(eckey, buf, len);
  }
  
  size_t ec_key_simple_priv2oct(const EC_KEY *eckey,
                                unsigned char *buf, size_t len)
  {
      size_t buf_len;
  
      buf_len = (EC_GROUP_order_bits(eckey->group) + 7) / 8;
      if (eckey->priv_key == NULL)
          return 0;
      if (buf == NULL)
          return buf_len;
      else if (len < buf_len)
          return 0;
  
      /* Octetstring may need leading zeros if BN is to short */
  
      if (BN_bn2binpad(eckey->priv_key, buf, buf_len) == -1) {
          ECerr(EC_F_EC_KEY_SIMPLE_PRIV2OCT, EC_R_BUFFER_TOO_SMALL);
          return 0;
      }
  
      return buf_len;
  }
  
  int EC_KEY_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
  {
      if (eckey->group == NULL || eckey->group->meth == NULL)
          return 0;
      if (eckey->group->meth->oct2priv == NULL) {
          ECerr(EC_F_EC_KEY_OCT2PRIV, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
          return 0;
      }
      return eckey->group->meth->oct2priv(eckey, buf, len);
  }
  
  int ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len)
  {
      if (eckey->priv_key == NULL)
          eckey->priv_key = BN_secure_new();
      if (eckey->priv_key == NULL) {
          ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_MALLOC_FAILURE);
          return 0;
      }
      eckey->priv_key = BN_bin2bn(buf, len, eckey->priv_key);
      if (eckey->priv_key == NULL) {
          ECerr(EC_F_EC_KEY_SIMPLE_OCT2PRIV, ERR_R_BN_LIB);
          return 0;
      }
      return 1;
  }
  
  size_t EC_KEY_priv2buf(const EC_KEY *eckey, unsigned char **pbuf)
  {
      size_t len;
      unsigned char *buf;
  
      len = EC_KEY_priv2oct(eckey, NULL, 0);
      if (len == 0)
          return 0;
      if ((buf = OPENtls_malloc(len)) == NULL) {
          ECerr(EC_F_EC_KEY_PRIV2BUF, ERR_R_MALLOC_FAILURE);
          return 0;
      }
      len = EC_KEY_priv2oct(eckey, buf, len);
      if (len == 0) {
          OPENtls_free(buf);
          return 0;
      }
      *pbuf = buf;
      return len;
  }
  
  int EC_KEY_can_sign(const EC_KEY *eckey)
  {
      if (eckey->group == NULL || eckey->group->meth == NULL
          || (eckey->group->meth->flags & EC_FLAGS_NO_SIGN))
          return 0;
      return 1;
  }
  