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Make psa_key_derivation_setup return early if the hash is not supported

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Otherwise the systematically generated algorithm-not-supported tests
complain when they try to start an operation and succeed.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine 2021-04-29 21:18:14 +02:00
parent 9efde4f2ec
commit 0cc417d34b
1 changed files with 19 additions and 0 deletions
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19
library/psa_crypto.c
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@ -5036,6 +5036,14 @@ static int is_kdf_alg_supported( psa_algorithm_t kdf_alg )
return( 0 );
}
static psa_status_t psa_hash_try_support( psa_algorithm_t alg )
{
psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT;
psa_status_t status = psa_hash_setup( &operation, alg );
psa_hash_abort( &operation );
return( status );
}
static psa_status_t psa_key_derivation_setup_kdf(
psa_key_derivation_operation_t *operation,
psa_algorithm_t kdf_alg )
@ -5048,16 +5056,27 @@ static psa_status_t psa_key_derivation_setup_kdf(
if( ! is_kdf_alg_supported( kdf_alg ) )
return( PSA_ERROR_NOT_SUPPORTED );
/* All currently supported key derivation algorithms are based on a
* hash algorithm. */
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 );
/* Make sure that hash_alg is a supported hash algorithm. Otherwise
* we might fail later, which is somewhat unfriendly and potentially
* risk-prone. */
psa_status_t status = psa_hash_try_support( hash_alg );
if( status != PSA_SUCCESS )
return( status );
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 );
}