Update and rename psa_get_empty_key_slot
Rename to psa_reserve_free_key_slot, as this function reserves a slot which is
free (not always empty) for filling.
Implement necessary state transitions and state checks.
Rename unlocked_persistent_key_slot to unused_persistent_key_slot.
Signed-off-by: Ryan Everett <ryan.everett@arm.com>
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index 32881e5..0f480fb 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -147,30 +147,31 @@
global_data.key_slots_initialized = 0;
}
-psa_status_t psa_get_empty_key_slot(psa_key_id_t *volatile_key_id,
- psa_key_slot_t **p_slot)
+psa_status_t psa_reserve_free_key_slot(psa_key_id_t *volatile_key_id,
+ psa_key_slot_t **p_slot)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
size_t slot_idx;
- psa_key_slot_t *selected_slot, *unlocked_persistent_key_slot;
+ psa_key_slot_t *selected_slot, *unused_persistent_key_slot;
if (!global_data.key_slots_initialized) {
status = PSA_ERROR_BAD_STATE;
goto error;
}
- selected_slot = unlocked_persistent_key_slot = NULL;
+ selected_slot = unused_persistent_key_slot = NULL;
for (slot_idx = 0; slot_idx < MBEDTLS_PSA_KEY_SLOT_COUNT; slot_idx++) {
psa_key_slot_t *slot = &global_data.key_slots[slot_idx];
- if (!psa_is_key_slot_occupied(slot)) {
+ if (slot->state == PSA_SLOT_EMPTY) {
selected_slot = slot;
break;
}
- if ((unlocked_persistent_key_slot == NULL) &&
- (!PSA_KEY_LIFETIME_IS_VOLATILE(slot->attr.lifetime)) &&
- (!psa_is_key_slot_locked(slot))) {
- unlocked_persistent_key_slot = slot;
+ if ((unused_persistent_key_slot == NULL) &&
+ (slot->state == PSA_SLOT_FULL) &&
+ (!psa_key_slot_has_readers(slot)) &&
+ (!PSA_KEY_LIFETIME_IS_VOLATILE(slot->attr.lifetime))) {
+ unused_persistent_key_slot = slot;
}
}
@@ -182,16 +183,24 @@
* storage.
*/
if ((selected_slot == NULL) &&
- (unlocked_persistent_key_slot != NULL)) {
- selected_slot = unlocked_persistent_key_slot;
- selected_slot->lock_count = 1;
- psa_wipe_key_slot(selected_slot);
+ (unused_persistent_key_slot != NULL)) {
+ selected_slot = unused_persistent_key_slot;
+ psa_register_read(selected_slot);
+ /* If the state is not changed then psa_wipe_key_slot
+ * will report an error. */
+ psa_key_slot_state_transition(selected_slot, PSA_SLOT_FULL,
+ PSA_SLOT_PENDING_DELETION);
+ status = psa_wipe_key_slot(selected_slot);
+ if (status != PSA_SUCCESS) {
+ goto error;
+ }
}
if (selected_slot != NULL) {
- status = psa_lock_key_slot(selected_slot);
+ status = psa_key_slot_state_transition(selected_slot, PSA_SLOT_EMPTY,
+ PSA_SLOT_FILLING);
if (status != PSA_SUCCESS) {
- goto error;
+ return status;
}
*volatile_key_id = PSA_KEY_ID_VOLATILE_MIN +
diff --git a/library/psa_crypto_slot_management.h b/library/psa_crypto_slot_management.h
index f0bbed9..b2cf570 100644
--- a/library/psa_crypto_slot_management.h
+++ b/library/psa_crypto_slot_management.h
@@ -95,23 +95,29 @@
* This does not affect persistent storage. */
void psa_wipe_all_key_slots(void);
-/** Find a free key slot.
+/** Find a free key slot and reserve it to be filled with a key.
*
- * 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.
+ * 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.
*
* \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 \emptydescription
- * \retval #PSA_ERROR_INSUFFICIENT_MEMORY \emptydescription
- * \retval #PSA_ERROR_BAD_STATE \emptydescription
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ * There were no free key slots.
+ * \retval #PSA_ERROR_BAD_STATE
+ * This function attempted to operate on a key slot which was in an
+ * unexpected state.
*/
-psa_status_t psa_get_empty_key_slot(psa_key_id_t *volatile_key_id,
- psa_key_slot_t **p_slot);
+psa_status_t psa_reserve_free_key_slot(psa_key_id_t *volatile_key_id,
+ psa_key_slot_t **p_slot);
+
/** Change the state of a key slot.
*
* This function changes the state of the key slot from expected_state to