/*
* PSA crypto layer on top of Mbed TLS crypto
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#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 first #MBEDTLS_PSA_KEY_SLOT_COUNT identifiers of the implementation
* range of key identifiers are reserved for volatile key identifiers.
*
* If \c id is a a volatile key identifier, #PSA_KEY_ID_VOLATILE_MIN - \c id
* indicates the key slot containing the volatile key definition. See
* psa_crypto_slot_management.c for details.
*/
/** The minimum value for a volatile key identifier.
*/
#define PSA_KEY_ID_VOLATILE_MIN PSA_KEY_ID_VENDOR_MIN
/** The maximum value for a volatile key identifier.
*/
#if defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC)
#define PSA_KEY_ID_VOLATILE_MAX (MBEDTLS_PSA_KEY_ID_BUILTIN_MIN - 1)
#else /* MBEDTLS_PSA_KEY_STORE_DYNAMIC */
#define PSA_KEY_ID_VOLATILE_MAX \
(PSA_KEY_ID_VOLATILE_MIN + MBEDTLS_PSA_KEY_SLOT_COUNT - 1)
#endif /* MBEDTLS_PSA_KEY_STORE_DYNAMIC */
/** 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 has been registered for reading.
* It is the responsibility of the caller to call psa_unregister_read(slot)
* when they have finished reading the contents of the slot.
*
* On failure, `*p_slot` is set to NULL. This ensures that it is always valid
* to call psa_unregister_read on the returned slot.
*
* \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 \emptydescription
* \retval #PSA_ERROR_STORAGE_FAILURE \emptydescription
* \retval #PSA_ERROR_DATA_CORRUPT \emptydescription
*/
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);
#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC)
/* Allow test code to customize the key slice length. We use this in tests
* that exhaust the key store to reach a full key store in reasonable time
* and memory.
*
* The length of each slice must be between 1 and
* (1 << KEY_ID_SLOT_INDEX_WIDTH) inclusive.
*
* The length for a given slice index must not change while
* the key store is initialized.
*/
extern size_t (*mbedtls_test_hook_psa_volatile_key_slice_length)(
size_t slice_idx);
/* The number of volatile key slices. */
size_t psa_key_slot_volatile_slice_count(void);
#endif
/** Delete all data from key slots in memory.
* This function is not thread safe, it wipes every key slot regardless of
* state and reader count. It should only be called when no slot is in use.
*
* This does not affect persistent storage. */
void psa_wipe_all_key_slots(void);
/** Find a free key slot and reserve it to be filled with a key.
*
* This function finds a key slot that is free,
* sets its state to PSA_SLOT_FILLING and then returns the slot.
*
* On success, the key slot's state is PSA_SLOT_FILLING.
* It is the responsibility of the caller to change the slot's state to
* PSA_SLOT_EMPTY/FULL once key creation has finished.
*
* If multi-threading is enabled, the caller must hold the
* global key slot mutex.
*
* \param[out] volatile_key_id - If null, reserve a cache slot for
* a persistent or built-in key.
* - If non-null, allocate a slot for
* a volatile key. On success,
* \p *volatile_key_id is the
* identifier corresponding to the
* returned slot. It is the caller's
* responsibility to set this key identifier
* in the attributes.
* \param[out] p_slot On success, a pointer to the slot.
*
* \retval #PSA_SUCCESS \emptydescription
* \retval #PSA_ERROR_INSUFFICIENT_MEMORY
* There were no free key slots.
* When #MBEDTLS_PSA_KEY_STORE_DYNAMIC is enabled, there was not
* enough memory to allocate more slots.
* \retval #PSA_ERROR_BAD_STATE \emptydescription
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* This function attempted to operate on a key slot which was in an
* unexpected state.
*/
psa_status_t psa_reserve_free_key_slot(psa_key_id_t *volatile_key_id,
psa_key_slot_t **p_slot);
#if defined(MBEDTLS_PSA_KEY_STORE_DYNAMIC)
/** Return a key slot to the free list.
*
* Call this function when a slot obtained from psa_reserve_free_key_slot()
* is no longer in use.
*
* If multi-threading is enabled, the caller must hold the
* global key slot mutex.
*
* \param slice_idx The slice containing the slot.
* This is `slot->slice_index` when the slot
* is obtained from psa_reserve_free_key_slot().
* \param slot The key slot.
*
* \retval #PSA_SUCCESS \emptydescription
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* This function attempted to operate on a key slot which was in an
* unexpected state.
*/
psa_status_t psa_free_key_slot(size_t slice_idx,
psa_key_slot_t *slot);
#endif /* MBEDTLS_PSA_KEY_STORE_DYNAMIC */
/** Change the state of a key slot.
*
* This function changes the state of the key slot from expected_state to
* new state. If the state of the slot was not expected_state, the state is
* unchanged.
*
* If multi-threading is enabled, the caller must hold the
* global key slot mutex.
*
* \param[in] slot The key slot.
* \param[in] expected_state The current state of the slot.
* \param[in] new_state The new state of the slot.
*
* \retval #PSA_SUCCESS
The key slot's state variable is new_state.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The slot's state was not expected_state.
*/
static inline psa_status_t psa_key_slot_state_transition(
psa_key_slot_t *slot, psa_key_slot_state_t expected_state,
psa_key_slot_state_t new_state)
{
if (slot->state != expected_state) {
return PSA_ERROR_CORRUPTION_DETECTED;
}
slot->state = new_state;
return PSA_SUCCESS;
}
/** Register as a reader of a key slot.
*
* This function increments the key slot registered reader counter by one.
* If multi-threading is enabled, the caller must hold the
* global key slot mutex.
*
* \param[in] slot The key slot.
*
* \retval #PSA_SUCCESS
The key slot registered reader counter was incremented.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The reader counter already reached its maximum value and was not
* increased, or the slot's state was not PSA_SLOT_FULL.
*/
static inline psa_status_t psa_register_read(psa_key_slot_t *slot)
{
if ((slot->state != PSA_SLOT_FULL) ||
(slot->var.occupied.registered_readers >= SIZE_MAX)) {
return PSA_ERROR_CORRUPTION_DETECTED;
}
slot->var.occupied.registered_readers++;
return PSA_SUCCESS;
}
/** Unregister from reading a key slot.
*
* This function decrements the key slot registered reader counter by one.
* If the state of the slot is PSA_SLOT_PENDING_DELETION,
* and there is only one registered reader (the caller),
* this function will call psa_wipe_key_slot().
* If multi-threading is enabled, the caller must hold the
* global key slot mutex.
*
* \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 reader counter has been
* decremented (and potentially wiped) successfully.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The slot's state was neither PSA_SLOT_FULL nor
* PSA_SLOT_PENDING_DELETION.
* Or a wipe was attempted and the slot's state was not
* PSA_SLOT_PENDING_DELETION.
* Or registered_readers was equal to 0.
*/
psa_status_t psa_unregister_read(psa_key_slot_t *slot);
/** Wrap a call to psa_unregister_read in the global key slot mutex.
*
* If threading is disabled, this simply calls psa_unregister_read.
*
* \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 reader counter has been
* decremented (and potentially wiped) successfully.
* \retval #PSA_ERROR_CORRUPTION_DETECTED
* The slot's state was neither PSA_SLOT_FULL nor
* PSA_SLOT_PENDING_DELETION.
* Or a wipe was attempted and the slot's state was not
* PSA_SLOT_PENDING_DELETION.
* Or registered_readers was equal to 0.
*/
psa_status_t psa_unregister_read_under_mutex(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 \emptydescription
* \retval #PSA_ERROR_INVALID_ARGUMENT \emptydescription
*/
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 \emptydescription
* \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 */
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