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Update semantics around driver context use in psa_cipher_setup

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Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
This commit is contained in:
Steven Cooreman 2020-09-10 14:54:14 +02:00
parent eca33c60f8
commit a07b9970c6
2 changed files with 47 additions and 48 deletions
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2
include/psa/crypto_struct.h
View File

@ -168,7 +168,7 @@ struct psa_cipher_operation_s
unsigned int key_set : 1;
unsigned int iv_required : 1;
unsigned int iv_set : 1;
unsigned int accelerator_set : 1; /* Indicates a driver is used instead of software fallback. */
unsigned int driver_in_use : 1; /* Indicates a driver is used instead of software fallback. */
uint8_t iv_size;
uint8_t block_size;
union

93
library/psa_crypto.c
View File

@ -4037,34 +4037,6 @@ rsa_exit:
/* Symmetric cryptography */
/****************************************************************/
/* Initialize the cipher operation structure. Once this function has been
* called, psa_cipher_abort can run and will do the right thing. */
static psa_status_t psa_cipher_init( psa_cipher_operation_t *operation,
psa_algorithm_t alg )
{
if( ! PSA_ALG_IS_CIPHER( alg ) )
{
memset( operation, 0, sizeof( *operation ) );
return( PSA_ERROR_INVALID_ARGUMENT );
}
operation->alg = alg;
operation->key_set = 0;
operation->iv_set = 0;
if( alg == PSA_ALG_ECB_NO_PADDING )
{
operation->iv_required = 0;
}
else
{
operation->iv_required = 1;
}
operation->accelerator_set = 0;
operation->iv_size = 0;
operation->block_size = 0;
return( PSA_SUCCESS );
}
static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
psa_key_handle_t handle,
psa_algorithm_t alg,
@ -4079,19 +4051,36 @@ static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
PSA_KEY_USAGE_ENCRYPT :
PSA_KEY_USAGE_DECRYPT );
status = psa_get_key_from_slot( handle, &slot, usage, alg );
if( status != PSA_SUCCESS )
goto exit;
/* A context must be freshly initialized before it can be set up. */
if( operation->alg != 0 )
return( PSA_ERROR_BAD_STATE );
status = psa_cipher_init( operation, alg );
if( status != PSA_SUCCESS )
return( status );
/* The requested algorithm must be one that can be processed by cipher. */
if( ! PSA_ALG_IS_CIPHER( alg ) )
{
memset( operation, 0, sizeof( *operation ) );
return( PSA_ERROR_INVALID_ARGUMENT );
}
/* Try doing this through a driver before using software fallback */
/* Reset the operation members to their initial state, except for alg. The
* alg member is used as an indicator that psa_cipher_abort needs to free
* allocated resources, which doesn't happen until later. */
operation->key_set = 0;
operation->iv_set = 0;
operation->driver_in_use = 0;
operation->iv_size = 0;
operation->block_size = 0;
if( alg == PSA_ALG_ECB_NO_PADDING )
operation->iv_required = 0;
else
operation->iv_required = 1;
/* Fetch key material from key storage. */
status = psa_get_key_from_slot( handle, &slot, usage, alg );
if( status != PSA_SUCCESS )
goto exit;
/* Try doing the operation through a driver before using software fallback. */
if( cipher_operation == MBEDTLS_ENCRYPT )
status = psa_driver_wrapper_cipher_encrypt_setup( &operation->ctx.driver,
slot,
@ -4104,20 +4093,30 @@ static psa_status_t psa_cipher_setup( psa_cipher_operation_t *operation,
if( status != PSA_ERROR_NOT_SUPPORTED ||
psa_key_lifetime_is_external( slot->attr.lifetime ) )
{
/* Indicate this operation is bound to an accelerator. When the driver
* setup succeeded, this indicates to the core to not call any mbedtls_
/* Indicate this operation is bound to a driver. When the driver setup
* succeeded, this indicates to the core to not call any mbedtls_
* functions for this operation (contexts are not interoperable).
* In case the drivers couldn't setup and there's no way to fallback,
* indicate to the core to not call mbedtls_cipher_free on an
* uninitialised mbed TLS cipher context. */
operation->accelerator_set = 1;
operation->driver_in_use = 1;
/* If the wrapper call succeeded, it allocated resources that need to be
* freed using psa_cipher_abort. Indicate this through setting alg. */
if( status == PSA_SUCCESS )
operation->alg = alg;
goto exit;
}
/* Proceed with initializing mbed TLS cipher context if no accelerator is
/* Proceed with initializing an mbed TLS cipher context if no driver is
* available for the given algorithm & key. */
mbedtls_cipher_init( &operation->ctx.cipher );
/* Once the cipher context is initialised, it needs to be freed using
* psa_cipher_abort. Indicate this through setting alg. */
operation->alg = alg;
key_bits = psa_get_key_slot_bits( slot );
cipher_info = mbedtls_cipher_info_from_psa( alg, slot->attr.type, key_bits, NULL );
if( cipher_info == NULL )
@ -4225,7 +4224,7 @@ psa_status_t psa_cipher_generate_iv( psa_cipher_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}
if( operation->accelerator_set == 1 )
if( operation->driver_in_use == 1 )
{
status = psa_driver_wrapper_cipher_generate_iv( &operation->ctx.driver,
iv,
@ -4269,7 +4268,7 @@ psa_status_t psa_cipher_set_iv( psa_cipher_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}
if( operation->accelerator_set == 1 )
if( operation->driver_in_use == 1 )
{
status = psa_driver_wrapper_cipher_set_iv( &operation->ctx.driver,
iv,
@ -4398,7 +4397,7 @@ psa_status_t psa_cipher_update( psa_cipher_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}
if( operation->accelerator_set == 1 )
if( operation->driver_in_use == 1 )
{
status = psa_driver_wrapper_cipher_update( &operation->ctx.driver,
input,
@ -4471,7 +4470,7 @@ psa_status_t psa_cipher_finish( psa_cipher_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}
if( operation->accelerator_set == 1 )
if( operation->driver_in_use == 1 )
{
status = psa_driver_wrapper_cipher_finish( &operation->ctx.driver,
output,
@ -4533,7 +4532,7 @@ psa_status_t psa_cipher_abort( psa_cipher_operation_t *operation )
{
if( operation->alg == 0 )
{
/* The object has (apparently) been initialized but it is not
/* The object has (apparently) been initialized but it is not (yet)
* in use. It's ok to call abort on such an object, and there's
* nothing to do. */
return( PSA_SUCCESS );
@ -4544,7 +4543,7 @@ psa_status_t psa_cipher_abort( psa_cipher_operation_t *operation )
if( ! PSA_ALG_IS_CIPHER( operation->alg ) )
return( PSA_ERROR_BAD_STATE );
if( operation->accelerator_set == 1 )
if( operation->driver_in_use == 1 )
psa_driver_wrapper_cipher_abort( &operation->ctx.driver );
else
mbedtls_cipher_free( &operation->ctx.cipher );
@ -4552,7 +4551,7 @@ psa_status_t psa_cipher_abort( psa_cipher_operation_t *operation )
operation->alg = 0;
operation->key_set = 0;
operation->iv_set = 0;
operation->accelerator_set = 0;
operation->driver_in_use = 0;
operation->iv_size = 0;
operation->block_size = 0;
operation->iv_required = 0;