Improve psa_generate_key_internal()

Small improvements to psa_generate_key_internal()
implementation:
. declare only once the status local variable and
  initialize it to PSA_ERROR_CORRUPTION_DETECTED
  to improve robustness against FI attacks.
. remove an unnecessary assignment.
. use type local variable instead of its global
  variable equivalent.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit is contained in:
Ronald Cron 2020-10-02 20:11:59 +02:00
parent 59ad77032f
commit f3bb761c00

View File

@ -5988,6 +5988,7 @@ static psa_status_t psa_generate_key_internal(
psa_key_slot_t *slot, size_t bits, psa_key_slot_t *slot, size_t bits,
const uint8_t *domain_parameters, size_t domain_parameters_size ) const uint8_t *domain_parameters, size_t domain_parameters_size )
{ {
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
psa_key_type_t type = slot->attr.type; psa_key_type_t type = slot->attr.type;
if( domain_parameters == NULL && domain_parameters_size != 0 ) if( domain_parameters == NULL && domain_parameters_size != 0 )
@ -5995,9 +5996,7 @@ static psa_status_t psa_generate_key_internal(
if( key_type_is_raw_bytes( type ) ) if( key_type_is_raw_bytes( type ) )
{ {
psa_status_t status; status = validate_unstructured_key_bit_size( type, bits );
status = validate_unstructured_key_bit_size( slot->attr.type, bits );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
@ -6011,7 +6010,6 @@ static psa_status_t psa_generate_key_internal(
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
return( status ); return( status );
slot->attr.bits = (psa_key_bits_t) bits;
#if defined(MBEDTLS_DES_C) #if defined(MBEDTLS_DES_C)
if( type == PSA_KEY_TYPE_DES ) if( type == PSA_KEY_TYPE_DES )
psa_des_set_key_parity( slot->key.data, psa_des_set_key_parity( slot->key.data,
@ -6026,7 +6024,6 @@ static psa_status_t psa_generate_key_internal(
mbedtls_rsa_context rsa; mbedtls_rsa_context rsa;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
int exponent; int exponent;
psa_status_t status;
if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS ) if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS )
return( PSA_ERROR_NOT_SUPPORTED ); return( PSA_ERROR_NOT_SUPPORTED );
/* Accept only byte-aligned keys, for the same reasons as /* Accept only byte-aligned keys, for the same reasons as
@ -6097,7 +6094,7 @@ static psa_status_t psa_generate_key_internal(
/* Make sure to always have an export representation available */ /* Make sure to always have an export representation available */
size_t bytes = PSA_BITS_TO_BYTES( bits ); size_t bytes = PSA_BITS_TO_BYTES( bits );
psa_status_t status = psa_allocate_buffer_to_slot( slot, bytes ); status = psa_allocate_buffer_to_slot( slot, bytes );
if( status != PSA_SUCCESS ) if( status != PSA_SUCCESS )
{ {
mbedtls_ecp_keypair_free( &ecp ); mbedtls_ecp_keypair_free( &ecp );