text: /*
   *  Public Key abstraction layer
   *
   *  Copyright The Mbed TLS Contributors
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  #include "common.h"
  
  #if defined(MBEDTLS_PK_C)
  #include "mbedtls/pk.h"
  #include "pk_wrap.h"
  
  #include "mbedtls/platform_util.h"
  #include "mbedtls/error.h"
  
  #if defined(MBEDTLS_RSA_C)
  #include "mbedtls/rsa.h"
  #endif
  #if defined(MBEDTLS_ECP_C)
  #include "mbedtls/ecp.h"
  #endif
  #if defined(MBEDTLS_ECDSA_C)
  #include "mbedtls/ecdsa.h"
  #endif
  
  #if defined(MBEDTLS_USE_PSA_CRYPTO)
  #include "mbedtls/psa_util.h"
  #endif
  
  #include <limits.h>
  #include <stdint.h>
  
  /* Parameter validation macros based on platform_util.h */
  #define PK_VALIDATE_RET( cond )    \
      MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA )
  #define PK_VALIDATE( cond )        \
      MBEDTLS_INTERNAL_VALIDATE( cond )
  
  /*
   * Initialise a mbedtls_pk_context
   */
  void mbedtls_pk_init( mbedtls_pk_context *ctx )
  {
      PK_VALIDATE( ctx != NULL );
  
      ctx->pk_info = NULL;
      ctx->pk_ctx = NULL;
  }
  
  /*
   * Free (the components of) a mbedtls_pk_context
   */
  void mbedtls_pk_free( mbedtls_pk_context *ctx )
  {
      if( ctx == NULL )
          return;
  
      if ( ctx->pk_info != NULL )
          ctx->pk_info->ctx_free_func( ctx->pk_ctx );
  
      mbedtls_platform_zeroize( ctx, sizeof( mbedtls_pk_context ) );
  }
  
  #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
  /*
   * Initialize a restart context
   */
  void mbedtls_pk_restart_init( mbedtls_pk_restart_ctx *ctx )
  {
      PK_VALIDATE( ctx != NULL );
      ctx->pk_info = NULL;
      ctx->rs_ctx = NULL;
  }
  
  /*
   * Free the components of a restart context
   */
  void mbedtls_pk_restart_free( mbedtls_pk_restart_ctx *ctx )
  {
      if( ctx == NULL || ctx->pk_info == NULL ||
          ctx->pk_info->rs_free_func == NULL )
      {
          return;
      }
  
      ctx->pk_info->rs_free_func( ctx->rs_ctx );
  
      ctx->pk_info = NULL;
      ctx->rs_ctx = NULL;
  }
  #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
  
  /*
   * Get pk_info structure from type
   */
  const mbedtls_pk_info_t * mbedtls_pk_info_from_type( mbedtls_pk_type_t pk_type )
  {
      switch( pk_type ) {
  #if defined(MBEDTLS_RSA_C)
          case MBEDTLS_PK_RSA:
              return( &mbedtls_rsa_info );
  #endif
  #if defined(MBEDTLS_ECP_C)
          case MBEDTLS_PK_ECKEY:
              return( &mbedtls_eckey_info );
          case MBEDTLS_PK_ECKEY_DH:
              return( &mbedtls_eckeydh_info );
  #endif
  #if defined(MBEDTLS_ECDSA_C)
          case MBEDTLS_PK_ECDSA:
              return( &mbedtls_ecdsa_info );
  #endif
          /* MBEDTLS_PK_RSA_ALT omitted on purpose */
          default:
              return( NULL );
      }
  }
  
  /*
   * Initialise context
   */
  int mbedtls_pk_setup( mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info )
  {
      PK_VALIDATE_RET( ctx != NULL );
      if( info == NULL || ctx->pk_info != NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
          return( MBEDTLS_ERR_PK_ALLOC_FAILED );
  
      ctx->pk_info = info;
  
      return( 0 );
  }
  
  #if defined(MBEDTLS_USE_PSA_CRYPTO)
  /*
   * Initialise a PSA-wrapping context
   */
  int mbedtls_pk_setup_opaque( mbedtls_pk_context *ctx,
                               const psa_key_id_t key )
  {
      const mbedtls_pk_info_t * const info = &mbedtls_pk_opaque_info;
      psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
      psa_key_id_t *pk_ctx;
      psa_key_type_t type;
  
      if( ctx == NULL || ctx->pk_info != NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( PSA_SUCCESS != psa_get_key_attributes( key, &attributes ) )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
      type = psa_get_key_type( &attributes );
      psa_reset_key_attributes( &attributes );
  
      /* Current implementation of can_do() relies on this. */
      if( ! PSA_KEY_TYPE_IS_ECC_KEY_PAIR( type ) )
          return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE) ;
  
      if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
          return( MBEDTLS_ERR_PK_ALLOC_FAILED );
  
      ctx->pk_info = info;
  
      pk_ctx = (psa_key_id_t *) ctx->pk_ctx;
      *pk_ctx = key;
  
      return( 0 );
  }
  #endif /* MBEDTLS_USE_PSA_CRYPTO */
  
  #if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
  /*
   * Initialize an RSA-alt context
   */
  int mbedtls_pk_setup_rsa_alt( mbedtls_pk_context *ctx, void * key,
                           mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
                           mbedtls_pk_rsa_alt_sign_func sign_func,
                           mbedtls_pk_rsa_alt_key_len_func key_len_func )
  {
      mbedtls_rsa_alt_context *rsa_alt;
      const mbedtls_pk_info_t *info = &mbedtls_rsa_alt_info;
  
      PK_VALIDATE_RET( ctx != NULL );
      if( ctx->pk_info != NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
          return( MBEDTLS_ERR_PK_ALLOC_FAILED );
  
      ctx->pk_info = info;
  
      rsa_alt = (mbedtls_rsa_alt_context *) ctx->pk_ctx;
  
      rsa_alt->key = key;
      rsa_alt->decrypt_func = decrypt_func;
      rsa_alt->sign_func = sign_func;
      rsa_alt->key_len_func = key_len_func;
  
      return( 0 );
  }
  #endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */
  
  /*
   * Tell if a PK can do the operations of the given type
   */
  int mbedtls_pk_can_do( const mbedtls_pk_context *ctx, mbedtls_pk_type_t type )
  {
      /* A context with null pk_info is not set up yet and can't do anything.
       * For backward compatibility, also accept NULL instead of a context
       * pointer. */
      if( ctx == NULL || ctx->pk_info == NULL )
          return( 0 );
  
      return( ctx->pk_info->can_do( type ) );
  }
  
  /*
   * Helper for mbedtls_pk_sign and mbedtls_pk_verify
   */
  static inline int pk_hashlen_helper( mbedtls_md_type_t md_alg, size_t *hash_len )
  {
      const mbedtls_md_info_t *md_info;
  
      if( *hash_len != 0 )
          return( 0 );
  
      if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
          return( -1 );
  
      *hash_len = mbedtls_md_get_size( md_info );
      return( 0 );
  }
  
  #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
  /*
   * Helper to set up a restart context if needed
   */
  static int pk_restart_setup( mbedtls_pk_restart_ctx *ctx,
                               const mbedtls_pk_info_t *info )
  {
      /* Don't do anything if already set up or invalid */
      if( ctx == NULL || ctx->pk_info != NULL )
          return( 0 );
  
      /* Should never happen when we're called */
      if( info->rs_alloc_func == NULL || info->rs_free_func == NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ( ctx->rs_ctx = info->rs_alloc_func() ) == NULL )
          return( MBEDTLS_ERR_PK_ALLOC_FAILED );
  
      ctx->pk_info = info;
  
      return( 0 );
  }
  #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
  
  /*
   * Verify a signature (restartable)
   */
  int mbedtls_pk_verify_restartable( mbedtls_pk_context *ctx,
                 mbedtls_md_type_t md_alg,
                 const unsigned char *hash, size_t hash_len,
                 const unsigned char *sig, size_t sig_len,
                 mbedtls_pk_restart_ctx *rs_ctx )
  {
      PK_VALIDATE_RET( ctx != NULL );
      PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
                       hash != NULL );
      PK_VALIDATE_RET( sig != NULL );
  
      if( ctx->pk_info == NULL ||
          pk_hashlen_helper( md_alg, &hash_len ) != 0 )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
  #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
      /* optimization: use non-restartable version if restart disabled */
      if( rs_ctx != NULL &&
          mbedtls_ecp_restart_is_enabled() &&
          ctx->pk_info->verify_rs_func != NULL )
      {
          int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
  
          if( ( ret = pk_restart_setup( rs_ctx, ctx->pk_info ) ) != 0 )
              return( ret );
  
          ret = ctx->pk_info->verify_rs_func( ctx->pk_ctx,
                     md_alg, hash, hash_len, sig, sig_len, rs_ctx->rs_ctx );
  
          if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
              mbedtls_pk_restart_free( rs_ctx );
  
          return( ret );
      }
  #else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
      (void) rs_ctx;
  #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
  
      if( ctx->pk_info->verify_func == NULL )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      return( ctx->pk_info->verify_func( ctx->pk_ctx, md_alg, hash, hash_len,
                                         sig, sig_len ) );
  }
  
  /*
   * Verify a signature
   */
  int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                 const unsigned char *hash, size_t hash_len,
                 const unsigned char *sig, size_t sig_len )
  {
      return( mbedtls_pk_verify_restartable( ctx, md_alg, hash, hash_len,
                                             sig, sig_len, NULL ) );
  }
  
  /*
   * Verify a signature with options
   */
  int mbedtls_pk_verify_ext( mbedtls_pk_type_t type, const void *options,
                     mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                     const unsigned char *hash, size_t hash_len,
                     const unsigned char *sig, size_t sig_len )
  {
      PK_VALIDATE_RET( ctx != NULL );
      PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
                       hash != NULL );
      PK_VALIDATE_RET( sig != NULL );
  
      if( ctx->pk_info == NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ! mbedtls_pk_can_do( ctx, type ) )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      if( type == MBEDTLS_PK_RSASSA_PSS )
      {
  #if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_PKCS1_V21)
          int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
          const mbedtls_pk_rsassa_pss_options *pss_opts;
  
  #if SIZE_MAX > UINT_MAX
          if( md_alg == MBEDTLS_MD_NONE && UINT_MAX < hash_len )
              return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  #endif /* SIZE_MAX > UINT_MAX */
  
          if( options == NULL )
              return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
          pss_opts = (const mbedtls_pk_rsassa_pss_options *) options;
  
          if( sig_len < mbedtls_pk_get_len( ctx ) )
              return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
  
          ret = mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_pk_rsa( *ctx ),
                                                   md_alg, (unsigned int) hash_len, hash,
                                                   pss_opts->mgf1_hash_id,
                                                   pss_opts->expected_salt_len,
                                                   sig );
          if( ret != 0 )
              return( ret );
  
          if( sig_len > mbedtls_pk_get_len( ctx ) )
              return( MBEDTLS_ERR_PK_SIG_LEN_MISMATCH );
  
          return( 0 );
  #else
          return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
  #endif /* MBEDTLS_RSA_C && MBEDTLS_PKCS1_V21 */
      }
  
      /* General case: no options */
      if( options != NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      return( mbedtls_pk_verify( ctx, md_alg, hash, hash_len, sig, sig_len ) );
  }
  
  /*
   * Make a signature (restartable)
   */
  int mbedtls_pk_sign_restartable( mbedtls_pk_context *ctx,
               mbedtls_md_type_t md_alg,
               const unsigned char *hash, size_t hash_len,
               unsigned char *sig, size_t *sig_len,
               int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
               mbedtls_pk_restart_ctx *rs_ctx )
  {
      PK_VALIDATE_RET( ctx != NULL );
      PK_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && hash_len == 0 ) ||
                       hash != NULL );
      PK_VALIDATE_RET( sig != NULL );
  
      if( ctx->pk_info == NULL ||
          pk_hashlen_helper( md_alg, &hash_len ) != 0 )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
  #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
      /* optimization: use non-restartable version if restart disabled */
      if( rs_ctx != NULL &&
          mbedtls_ecp_restart_is_enabled() &&
          ctx->pk_info->sign_rs_func != NULL )
      {
          int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
  
          if( ( ret = pk_restart_setup( rs_ctx, ctx->pk_info ) ) != 0 )
              return( ret );
  
          ret = ctx->pk_info->sign_rs_func( ctx->pk_ctx, md_alg,
                  hash, hash_len, sig, sig_len, f_rng, p_rng, rs_ctx->rs_ctx );
  
          if( ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
              mbedtls_pk_restart_free( rs_ctx );
  
          return( ret );
      }
  #else /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
      (void) rs_ctx;
  #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
  
      if( ctx->pk_info->sign_func == NULL )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      return( ctx->pk_info->sign_func( ctx->pk_ctx, md_alg, hash, hash_len,
                                       sig, sig_len, f_rng, p_rng ) );
  }
  
  /*
   * Make a signature
   */
  int mbedtls_pk_sign( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
               const unsigned char *hash, size_t hash_len,
               unsigned char *sig, size_t *sig_len,
               int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
  {
      return( mbedtls_pk_sign_restartable( ctx, md_alg, hash, hash_len,
                                           sig, sig_len, f_rng, p_rng, NULL ) );
  }
  
  /*
   * Decrypt message
   */
  int mbedtls_pk_decrypt( mbedtls_pk_context *ctx,
                  const unsigned char *input, size_t ilen,
                  unsigned char *output, size_t *olen, size_t osize,
                  int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
  {
      PK_VALIDATE_RET( ctx != NULL );
      PK_VALIDATE_RET( input != NULL || ilen == 0 );
      PK_VALIDATE_RET( output != NULL || osize == 0 );
      PK_VALIDATE_RET( olen != NULL );
  
      if( ctx->pk_info == NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ctx->pk_info->decrypt_func == NULL )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      return( ctx->pk_info->decrypt_func( ctx->pk_ctx, input, ilen,
                  output, olen, osize, f_rng, p_rng ) );
  }
  
  /*
   * Encrypt message
   */
  int mbedtls_pk_encrypt( mbedtls_pk_context *ctx,
                  const unsigned char *input, size_t ilen,
                  unsigned char *output, size_t *olen, size_t osize,
                  int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
  {
      PK_VALIDATE_RET( ctx != NULL );
      PK_VALIDATE_RET( input != NULL || ilen == 0 );
      PK_VALIDATE_RET( output != NULL || osize == 0 );
      PK_VALIDATE_RET( olen != NULL );
  
      if( ctx->pk_info == NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ctx->pk_info->encrypt_func == NULL )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      return( ctx->pk_info->encrypt_func( ctx->pk_ctx, input, ilen,
                  output, olen, osize, f_rng, p_rng ) );
  }
  
  /*
   * Check public-private key pair
   */
  int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv )
  {
      PK_VALIDATE_RET( pub != NULL );
      PK_VALIDATE_RET( prv != NULL );
  
      if( pub->pk_info == NULL ||
          prv->pk_info == NULL )
      {
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
      }
  
      if( prv->pk_info->check_pair_func == NULL )
          return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
  
      if( prv->pk_info->type == MBEDTLS_PK_RSA_ALT )
      {
          if( pub->pk_info->type != MBEDTLS_PK_RSA )
              return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
      }
      else
      {
          if( pub->pk_info != prv->pk_info )
              return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
      }
  
      return( prv->pk_info->check_pair_func( pub->pk_ctx, prv->pk_ctx ) );
  }
  
  /*
   * Get key size in bits
   */
  size_t mbedtls_pk_get_bitlen( const mbedtls_pk_context *ctx )
  {
      /* For backward compatibility, accept NULL or a context that
       * isn't set up yet, and return a fake value that should be safe. */
      if( ctx == NULL || ctx->pk_info == NULL )
          return( 0 );
  
      return( ctx->pk_info->get_bitlen( ctx->pk_ctx ) );
  }
  
  /*
   * Export debug information
   */
  int mbedtls_pk_debug( const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items )
  {
      PK_VALIDATE_RET( ctx != NULL );
      if( ctx->pk_info == NULL )
          return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
  
      if( ctx->pk_info->debug_func == NULL )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      ctx->pk_info->debug_func( ctx->pk_ctx, items );
      return( 0 );
  }
  
  /*
   * Access the PK type name
   */
  const char *mbedtls_pk_get_name( const mbedtls_pk_context *ctx )
  {
      if( ctx == NULL || ctx->pk_info == NULL )
          return( "invalid PK" );
  
      return( ctx->pk_info->name );
  }
  
  /*
   * Access the PK type
   */
  mbedtls_pk_type_t mbedtls_pk_get_type( const mbedtls_pk_context *ctx )
  {
      if( ctx == NULL || ctx->pk_info == NULL )
          return( MBEDTLS_PK_NONE );
  
      return( ctx->pk_info->type );
  }
  
  #if defined(MBEDTLS_USE_PSA_CRYPTO)
  /*
   * Load the key to a PSA key slot,
   * then turn the PK context into a wrapper for that key slot.
   *
   * Currently only works for EC private keys.
   */
  int mbedtls_pk_wrap_as_opaque( mbedtls_pk_context *pk,
                                 psa_key_id_t *key,
                                 psa_algorithm_t hash_alg )
  {
  #if !defined(MBEDTLS_ECP_C)
      ((void) pk);
      ((void) key);
      ((void) hash_alg);
      return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  #else
      const mbedtls_ecp_keypair *ec;
      unsigned char d[MBEDTLS_ECP_MAX_BYTES];
      size_t d_len;
      psa_ecc_family_t curve_id;
      psa_key_attributes_t attributes = PSA_KEY_ATTRIBUTES_INIT;
      psa_key_type_t key_type;
      size_t bits;
      int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
  
      /* export the private key material in the format PSA wants */
      if( mbedtls_pk_get_type( pk ) != MBEDTLS_PK_ECKEY )
          return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
  
      ec = mbedtls_pk_ec( *pk );
      d_len = ( ec->grp.nbits + 7 ) / 8;
      if( ( ret = mbedtls_mpi_write_binary( &ec->d, d, d_len ) ) != 0 )
          return( ret );
  
      curve_id = mbedtls_ecc_group_to_psa( ec->grp.id, &bits );
      key_type = PSA_KEY_TYPE_ECC_KEY_PAIR( curve_id );
  
      /* prepare the key attributes */
      psa_set_key_type( &attributes, key_type );
      psa_set_key_bits( &attributes, bits );
      psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_SIGN_HASH );
      psa_set_key_algorithm( &attributes, PSA_ALG_ECDSA(hash_alg) );
  
      /* import private key into PSA */
      if( PSA_SUCCESS != psa_import_key( &attributes, d, d_len, key ) )
          return( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED );
  
      /* make PK context wrap the key slot */
      mbedtls_pk_free( pk );
      mbedtls_pk_init( pk );
  
      return( mbedtls_pk_setup_opaque( pk, *key ) );
  #endif /* MBEDTLS_ECP_C */
  }
  #endif /* MBEDTLS_USE_PSA_CRYPTO */
  #endif /* MBEDTLS_PK_C */
  