Simplify is_kdf_alg_supported in psa_key_derivation_setup_kdf

No behavior change.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine 2021-04-29 21:10:00 +02:00
parent 23cb12ef9f
commit cdacf0431b

View File

@ -4353,51 +4353,47 @@ psa_status_t psa_key_derivation_output_key( const psa_key_attributes_t *attribut
/****************************************************************/
#if defined(AT_LEAST_ONE_BUILTIN_KDF)
static int is_kdf_alg_supported( psa_algorithm_t kdf_alg )
{
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
if( PSA_ALG_IS_HKDF( kdf_alg ) )
return( 1 );
#endif
#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF)
if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) )
return( 1 );
#endif
#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
return( 1 );
#endif
return( 0 );
}
static psa_status_t psa_key_derivation_setup_kdf(
psa_key_derivation_operation_t *operation,
psa_algorithm_t kdf_alg )
{
int is_kdf_alg_supported;
/* Make sure that operation->ctx is properly zero-initialised. (Macro
* initialisers for this union leave some bytes unspecified.) */
memset( &operation->ctx, 0, sizeof( operation->ctx ) );
/* Make sure that kdf_alg is a supported key derivation algorithm. */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
if( PSA_ALG_IS_HKDF( kdf_alg ) )
is_kdf_alg_supported = 1;
else
#endif
#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PRF)
if( PSA_ALG_IS_TLS12_PRF( kdf_alg ) )
is_kdf_alg_supported = 1;
else
#endif
#if defined(MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS)
if( PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) )
is_kdf_alg_supported = 1;
else
#endif
is_kdf_alg_supported = 0;
if( ! is_kdf_alg_supported( kdf_alg ) )
return( PSA_ERROR_NOT_SUPPORTED );
if( is_kdf_alg_supported )
psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg );
size_t hash_size = PSA_HASH_LENGTH( hash_alg );
if( hash_size == 0 )
return( PSA_ERROR_NOT_SUPPORTED );
if( ( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) &&
! ( hash_alg == PSA_ALG_SHA_256 || hash_alg == PSA_ALG_SHA_384 ) )
{
psa_algorithm_t hash_alg = PSA_ALG_HKDF_GET_HASH( kdf_alg );
size_t hash_size = PSA_HASH_LENGTH( hash_alg );
if( hash_size == 0 )
return( PSA_ERROR_NOT_SUPPORTED );
if( ( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) &&
! ( hash_alg == PSA_ALG_SHA_256 || hash_alg == PSA_ALG_SHA_384 ) )
{
return( PSA_ERROR_NOT_SUPPORTED );
}
operation->capacity = 255 * hash_size;
return( PSA_SUCCESS );
return( PSA_ERROR_NOT_SUPPORTED );
}
return( PSA_ERROR_NOT_SUPPORTED );
operation->capacity = 255 * hash_size;
return( PSA_SUCCESS );
}
#endif /* AT_LEAST_ONE_BUILTIN_KDF */