Make number of key slots externally configurable

changes to make number of key slots externally configurable
changed define name from PSA_KEY_SLOT_COUNT to MBEDTLS_PSA_KEY_SLOT_COUNT

Author: Nir Sonnenschein

include/psa/crypto_extra.h

@@ -121,6 +121,14 @@ psa_status_t mbedtls_psa_inject_entropy(const unsigned char *seed,
                                         size_t seed_size);
 
 
+/* The Number of key slots (plus one because 0 is not used).
+ * The value is a compile-time constant for now, for simplicity. */
+#if defined(MBEDTLS_PSA_KEY_SLOT_COUNT)
+#else
+    #define MBEDTLS_PSA_KEY_SLOT_COUNT 32
+#endif /*MBEDTLS_PSA_KEY_SLOT_COUNT*/
+
+
 #ifdef __cplusplus
 }
 #endif

library/psa_crypto_slot_management.c

@@ -46,7 +46,7 @@
 
 typedef struct
 {
-    psa_key_slot_t key_slots[PSA_KEY_SLOT_COUNT];
+    psa_key_slot_t key_slots[MBEDTLS_PSA_KEY_SLOT_COUNT];
     unsigned key_slots_initialized : 1;
 } psa_global_data_t;
 
@@ -90,7 +90,7 @@ psa_status_t psa_initialize_key_slots( void )
 void psa_wipe_all_key_slots( void )
 {
     psa_key_handle_t key;
-    for( key = 1; key <= PSA_KEY_SLOT_COUNT; key++ )
+    for( key = 1; key <= MBEDTLS_PSA_KEY_SLOT_COUNT; key++ )
     {
         psa_key_slot_t *slot = &global_data.key_slots[key - 1];
         (void) psa_wipe_key_slot( slot );
@@ -108,7 +108,7 @@ void psa_wipe_all_key_slots( void )
  */
 static psa_status_t psa_internal_allocate_key_slot( psa_key_handle_t *handle )
 {
-    for( *handle = PSA_KEY_SLOT_COUNT; *handle != 0; --( *handle ) )
+    for( *handle = MBEDTLS_PSA_KEY_SLOT_COUNT; *handle != 0; --( *handle ) )
     {
         psa_key_slot_t *slot = &global_data.key_slots[*handle - 1];
         if( ! slot->allocated )

library/psa_crypto_slot_management.h

@@ -22,10 +22,6 @@
 #ifndef PSA_CRYPTO_SLOT_MANAGEMENT_H
 #define PSA_CRYPTO_SLOT_MANAGEMENT_H
 
-/* Number of key slots (plus one because 0 is not used).
- * The value is a compile-time constant for now, for simplicity. */
-#define PSA_KEY_SLOT_COUNT 32
-
 /** Access a key slot at the given handle.
  *
  * \param handle        Key handle to query.

library/psa_crypto_storage.h

@@ -51,7 +51,7 @@ extern "C" {
  * - Using the ITS backend, all key ids are ok except 0xFFFFFF52
  *   (#PSA_CRYPTO_ITS_RANDOM_SEED_UID) for which the file contains the
  *   device's random seed (if this feature is enabled).
- * - Only key ids from 1 to #PSA_KEY_SLOT_COUNT are actually used.
+ * - Only key ids from 1 to #MBEDTLS_PSA_KEY_SLOT_COUNT are actually used.
  *
  * Since we need to preserve the random seed, avoid using that key slot.
  * Reserve a whole range of key slots just in case something else comes up.