Move the key slot array to the slot management module
Move the key slot array and its initialization and wiping to the slot
management module.
Also move the lowest-level key slot access function psa_get_key_slot
and the auxiliary function for slot allocation
psa_internal_allocate_key_slot to the slot management module.
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index ae5e146..6d5c7d4 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -29,6 +29,7 @@
#include "psa/crypto.h"
+#include "psa_crypto_core.h"
#include "psa_crypto_slot_management.h"
#include "psa_crypto_storage.h"
@@ -43,6 +44,81 @@
#define ARRAY_LENGTH( array ) ( sizeof( array ) / sizeof( *( array ) ) )
+typedef struct
+{
+ psa_key_slot_t key_slots[PSA_KEY_SLOT_COUNT];
+ unsigned key_slots_initialized : 1;
+} psa_global_data_t;
+
+psa_global_data_t global_data;
+
+/* Access a key slot at the given handle. The handle of a key slot is
+ * the index of the slot in the global slot array, plus one so that handles
+ * start at 1 and not 0. */
+psa_status_t psa_get_key_slot( psa_key_handle_t handle,
+ psa_key_slot_t **p_slot )
+{
+ psa_key_slot_t *slot = NULL;
+
+ if( ! global_data.key_slots_initialized )
+ return( PSA_ERROR_BAD_STATE );
+
+ /* 0 is not a valid handle under any circumstance. This
+ * implementation provides slots number 1 to N where N is the
+ * number of available slots. */
+ if( handle == 0 || handle > ARRAY_LENGTH( global_data.key_slots ) )
+ return( PSA_ERROR_INVALID_HANDLE );
+ slot = &global_data.key_slots[handle - 1];
+
+ /* If the slot hasn't been allocated, the handle is invalid. */
+ if( ! slot->allocated )
+ return( PSA_ERROR_INVALID_HANDLE );
+
+ *p_slot = slot;
+ return( PSA_SUCCESS );
+}
+
+psa_status_t psa_initialize_key_slots( void )
+{
+ /* Nothing to do: program startup and psa_wipe_all_key_slots() both
+ * guarantee that the key slots are initialized to all-zero, which
+ * means that all the key slots are in a valid, empty state. */
+ global_data.key_slots_initialized = 1;
+ return( PSA_SUCCESS );
+}
+
+void psa_wipe_all_key_slots( void )
+{
+ psa_key_handle_t key;
+ for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
+ {
+ psa_key_slot_t *slot = &global_data.key_slots[key - 1];
+ (void) psa_wipe_key_slot( slot );
+ }
+ global_data.key_slots_initialized = 0;
+}
+
+/** Find a free key slot and mark it as in use.
+ *
+ * \param[out] handle On success, a slot number that is not in use.
+ *
+ * \retval #PSA_SUCCESS
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ */
+static psa_status_t psa_internal_allocate_key_slot( psa_key_handle_t *handle )
+{
+ for( *handle = PSA_KEY_SLOT_COUNT; *handle != 0; --( *handle ) )
+ {
+ psa_key_slot_t *slot = &global_data.key_slots[*handle - 1];
+ if( ! slot->allocated )
+ {
+ slot->allocated = 1;
+ return( PSA_SUCCESS );
+ }
+ }
+ return( PSA_ERROR_INSUFFICIENT_MEMORY );
+}
+
psa_status_t psa_allocate_key( psa_key_type_t type,
size_t max_bits,
psa_key_handle_t *handle )