/*
* PSA crypto support for secure element drivers
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#ifndef PSA_CRYPTO_SE_H
#define PSA_CRYPTO_SE_H
/*
* Include the build-time configuration information header. Here, we do not
* include `"mbedtls/build_info.h"` directly but `"psa/build_info.h"`, which
* is basically just an alias to it. This is to ease the maintenance of the
* TF-PSA-Crypto repository which has a different build system and
* configuration.
*/
#include "psa/build_info.h"
#include "psa/crypto.h"
#include "psa/crypto_se_driver.h"
/** The maximum location value that this implementation supports
* for a secure element.
*
* This is not a characteristic that each PSA implementation has, but a
* limitation of the current implementation due to the constraints imposed
* by storage. See #PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE.
*
* The minimum location value for a secure element is 1, like on any
* PSA implementation (0 means a transparent key).
*/
#define PSA_MAX_SE_LOCATION 255
/** The base of the range of ITS file identifiers for secure element
* driver persistent data.
*
* We use a slice of the implementation reserved range 0xffff0000..0xffffffff,
* specifically the range 0xfffffe00..0xfffffeff. The length of this range
* drives the value of #PSA_MAX_SE_LOCATION. The identifier 0xfffffe00 is
* actually not used since it corresponds to #PSA_KEY_LOCATION_LOCAL_STORAGE
* which doesn't have a driver.
*/
#define PSA_CRYPTO_SE_DRIVER_ITS_UID_BASE ((psa_key_id_t) 0xfffffe00)
/** The maximum number of registered secure element driver locations. */
#define PSA_MAX_SE_DRIVERS 4
/** Unregister all secure element drivers.
*
* \warning Do not call this function while the library is in the initialized
* state. This function is only intended to be called at the end
* of mbedtls_psa_crypto_free().
*/
void psa_unregister_all_se_drivers(void);
/** Initialize all secure element drivers.
*
* Called from psa_crypto_init().
*/
psa_status_t psa_init_all_se_drivers(void);
/** A structure that describes a registered secure element driver.
*
* A secure element driver table entry contains a pointer to the
* driver's method table as well as the driver context structure.
*/
typedef struct psa_se_drv_table_entry_s psa_se_drv_table_entry_t;
/** Return the secure element driver information for a lifetime value.
*
* \param lifetime The lifetime value to query.
* \param[out] p_methods On output, if there is a driver,
* \c *methods points to its method table.
* Otherwise \c *methods is \c NULL.
* \param[out] p_drv_context On output, if there is a driver,
* \c *drv_context points to its context
* structure.
* Otherwise \c *drv_context is \c NULL.
*
* \retval 1
* \p lifetime corresponds to a registered driver.
* \retval 0
* \p lifetime does not correspond to a registered driver.
*/
int psa_get_se_driver(psa_key_lifetime_t lifetime,
const psa_drv_se_t **p_methods,
psa_drv_se_context_t **p_drv_context);
/** Return the secure element driver table entry for a lifetime value.
*
* \param lifetime The lifetime value to query.
*
* \return The driver table entry for \p lifetime, or
* \p NULL if \p lifetime does not correspond to a registered driver.
*/
psa_se_drv_table_entry_t *psa_get_se_driver_entry(
psa_key_lifetime_t lifetime);
/** Return the method table for a secure element driver.
*
* \param[in] driver The driver table entry to access, or \c NULL.
*
* \return The driver's method table.
* \c NULL if \p driver is \c NULL.
*/
const psa_drv_se_t *psa_get_se_driver_methods(
const psa_se_drv_table_entry_t *driver);
/** Return the context of a secure element driver.
*
* \param[in] driver The driver table entry to access, or \c NULL.
*
* \return A pointer to the driver context.
* \c NULL if \p driver is \c NULL.
*/
psa_drv_se_context_t *psa_get_se_driver_context(
psa_se_drv_table_entry_t *driver);
/** Find a free slot for a key that is to be created.
*
* This function calls the relevant method in the driver to find a suitable
* slot for a key with the given attributes.
*
* \param[in] attributes Metadata about the key that is about to be created.
* \param[in] driver The driver table entry to query.
* \param[out] slot_number On success, a slot number that is free in this
* secure element.
*/
psa_status_t psa_find_se_slot_for_key(
const psa_key_attributes_t *attributes,
psa_key_creation_method_t method,
psa_se_drv_table_entry_t *driver,
psa_key_slot_number_t *slot_number);
/** Destroy a key in a secure element.
*
* This function calls the relevant driver method to destroy a key
* and updates the driver's persistent data.
*/
psa_status_t psa_destroy_se_key(psa_se_drv_table_entry_t *driver,
psa_key_slot_number_t slot_number);
/** Load the persistent data of a secure element driver.
*
* \param driver The driver table entry containing the persistent
* data to load from storage.
*
* \return #PSA_SUCCESS
* \return #PSA_ERROR_NOT_SUPPORTED
* \return #PSA_ERROR_DOES_NOT_EXIST
* \return #PSA_ERROR_STORAGE_FAILURE
* \return #PSA_ERROR_DATA_CORRUPT
* \return #PSA_ERROR_INVALID_ARGUMENT
*/
psa_status_t psa_load_se_persistent_data(
const psa_se_drv_table_entry_t *driver);
/** Save the persistent data of a secure element driver.
*
* \param[in] driver The driver table entry containing the persistent
* data to save to storage.
*
* \return #PSA_SUCCESS
* \return #PSA_ERROR_NOT_SUPPORTED
* \return #PSA_ERROR_NOT_PERMITTED
* \return #PSA_ERROR_NOT_SUPPORTED
* \return #PSA_ERROR_INSUFFICIENT_STORAGE
* \return #PSA_ERROR_STORAGE_FAILURE
* \return #PSA_ERROR_INVALID_ARGUMENT
*/
psa_status_t psa_save_se_persistent_data(
const psa_se_drv_table_entry_t *driver);
/** Destroy the persistent data of a secure element driver.
*
* This is currently only used for testing.
*
* \param[in] location The location identifier for the driver whose
* persistent data is to be erased.
*/
psa_status_t psa_destroy_se_persistent_data(psa_key_location_t location);
/** The storage representation of a key whose data is in a secure element.
*/
typedef struct {
uint8_t slot_number[sizeof(psa_key_slot_number_t)];
} psa_se_key_data_storage_t;
#endif /* PSA_CRYPTO_SE_H */