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/*
* PSA crypto layer on top of Mbed TLS crypto
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef PSA_CRYPTO_SLOT_MANAGEMENT_H
#define PSA_CRYPTO_SLOT_MANAGEMENT_H
#include "psa/crypto.h"
#include "psa_crypto_core.h"
#include "psa_crypto_se.h"
/** Range of volatile key identifiers.
*
* The last #MBEDTLS_PSA_KEY_SLOT_COUNT identifiers of the implementation
* range of key identifiers are reserved for volatile key identifiers.
* A volatile key identifier is equal to #PSA_KEY_ID_VOLATILE_MIN plus the
* index of the key slot containing the volatile key definition.
*/
/** The minimum value for a volatile key identifier.
*/
#define PSA_KEY_ID_VOLATILE_MIN ( PSA_KEY_ID_VENDOR_MAX - \
MBEDTLS_PSA_KEY_SLOT_COUNT + 1 )
/** The maximum value for a volatile key identifier.
*/
#define PSA_KEY_ID_VOLATILE_MAX PSA_KEY_ID_VENDOR_MAX
/** Test whether a key identifier is a volatile key identifier.
*
* \param key_id Key identifier to test.
*
* \retval 1
* The key identifier is a volatile key identifier.
* \retval 0
* The key identifier is not a volatile key identifier.
*/
static inline int psa_key_id_is_volatile( psa_key_id_t key_id )
{
return( ( key_id >= PSA_KEY_ID_VOLATILE_MIN ) &&
( key_id <= PSA_KEY_ID_VOLATILE_MAX ) );
}
/** Get the description of a key given its identifier and lock it.
*
* The descriptions of volatile keys and loaded persistent keys are stored in
* key slots. This function returns a pointer to the key slot containing the
* description of a key given its identifier.
*
* In case of a persistent key, the function loads the description of the key
* into a key slot if not already done.
*
* On success, the returned key slot is locked. It is the responsibility of
* the caller to unlock the key slot when it does not access it anymore.
*
* \param key Key identifier to query.
* \param[out] p_slot On success, `*p_slot` contains a pointer to the
* key slot containing the description of the key
* identified by \p key.
*
* \retval #PSA_SUCCESS
* \p *p_slot contains a pointer to the key slot containing the
* description of the key identified by \p key.
* The key slot counter has been incremented.
* \retval #PSA_ERROR_BAD_STATE
* The library has not been initialized.
* \retval #PSA_ERROR_INVALID_HANDLE
* \p key is not a valid key identifier.
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* \p key is a persistent key identifier. The implementation does not
* have sufficient resources to load the persistent key. This can be
* due to a lack of empty key slot, or available memory.
* \retval #PSA_ERROR_DOES_NOT_EXIST
* There is no key with key identifier \p key.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* \retval #PSA_ERROR_STORAGE_FAILURE
* \retval #PSA_ERROR_DATA_CORRUPT
*/
psa_status_t psa_get_and_lock_key_slot( mbedtls_svc_key_id_t key,
psa_key_slot_t **p_slot );
/** Initialize the key slot structures.
*
* \retval #PSA_SUCCESS
* Currently this function always succeeds.
*/
psa_status_t psa_initialize_key_slots( void );
/** Delete all data from key slots in memory.
*
* This does not affect persistent storage. */
void psa_wipe_all_key_slots( void );
/** Find a free key slot.
*
* This function returns a key slot that is available for use and is in its
* ground state (all-bits-zero). On success, the key slot is locked. It is
* the responsibility of the caller to unlock the key slot when it does not
* access it anymore.
*
* \param[out] volatile_key_id On success, volatile key identifier
* associated to the returned slot.
* \param[out] p_slot On success, a pointer to the slot.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* \retval #PSA_ERROR_BAD_STATE
*/
psa_status_t psa_get_empty_key_slot( psa_key_id_t *volatile_key_id,
psa_key_slot_t **p_slot );
/** Lock a key slot.
*
* This function increments the key slot lock counter by one.
*
* \param[in] slot The key slot.
*
* \retval #PSA_SUCCESS
The key slot lock counter was incremented.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The lock counter already reached its maximum value and was not
* increased.
*/
static inline psa_status_t psa_lock_key_slot( psa_key_slot_t *slot )
{
if( slot->lock_count >= SIZE_MAX )
return( PSA_ERROR_CORRUPTION_DETECTED );
slot->lock_count++;
return( PSA_SUCCESS );
}
/** Unlock a key slot.
*
* This function decrements the key slot lock counter by one.
*
* \note To ease the handling of errors in retrieving a key slot
* a NULL input pointer is valid, and the function returns
* successfully without doing anything in that case.
*
* \param[in] slot The key slot.
* \retval #PSA_SUCCESS
* \p slot is NULL or the key slot lock counter has been
* decremented successfully.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The lock counter was equal to 0.
*
*/
psa_status_t psa_unlock_key_slot( psa_key_slot_t *slot );
/** Test whether a lifetime designates a key in an external cryptoprocessor.
*
* \param lifetime The lifetime to test.
*
* \retval 1
* The lifetime designates an external key. There should be a
* registered driver for this lifetime, otherwise the key cannot
* be created or manipulated.
* \retval 0
* The lifetime designates a key that is volatile or in internal
* storage.
*/
static inline int psa_key_lifetime_is_external( psa_key_lifetime_t lifetime )
{
return( PSA_KEY_LIFETIME_GET_LOCATION( lifetime )
!= PSA_KEY_LOCATION_LOCAL_STORAGE );
}
/** Validate a key's location.
*
* This function checks whether the key's attributes point to a location that
* is known to the PSA Core, and returns the driver function table if the key
* is to be found in an external location.
*
* \param[in] lifetime The key lifetime attribute.
* \param[out] p_drv On success, when a key is located in external
* storage, returns a pointer to the driver table
* associated with the key's storage location.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_INVALID_ARGUMENT
*/
psa_status_t psa_validate_key_location( psa_key_lifetime_t lifetime,
psa_se_drv_table_entry_t **p_drv );
/** Validate the persistence of a key.
*
* \param[in] lifetime The key lifetime attribute.
*
* \retval #PSA_SUCCESS
* \retval #PSA_ERROR_NOT_SUPPORTED The key is persistent but persistent keys
* are not supported.
*/
psa_status_t psa_validate_key_persistence( psa_key_lifetime_t lifetime );
/** Validate a key identifier.
*
* \param[in] key The key identifier.
* \param[in] vendor_ok Non-zero to indicate that key identifiers in the
* vendor range are allowed, volatile key identifiers
* excepted \c 0 otherwise.
*
* \retval <> 0 if the key identifier is valid, 0 otherwise.
*/
int psa_is_valid_key_id( mbedtls_svc_key_id_t key, int vendor_ok );
#endif /* PSA_CRYPTO_SLOT_MANAGEMENT_H */