Update semantics around driver context use in psa_cipher_setup
Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index b26588f..861850c 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -168,7 +168,7 @@
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
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 647ca62..6b25903 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -4037,34 +4037,6 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
{
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 @@
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 @@
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;
