Assert that key ID ranges don't overlap

Ensure that a key ID can't be in range for more than one of volatile keys,
persistent (i.e. user-chosen) keys or built-in keys.

Signed-off-by: Gilles Peskine <[email protected]>

library/psa_crypto_slot_management.c

@@ -26,6 +26,37 @@
 
 #define ARRAY_LENGTH(array) (sizeof(array) / sizeof(*(array)))
 
+
+
+/* Make sure we have distinct ranges of key identifiers for distinct
+ * purposes. */
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_USER_MIN < PSA_KEY_ID_USER_MAX,
+                      "Empty user key ID range");
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_VENDOR_MIN < PSA_KEY_ID_VENDOR_MAX,
+                      "Empty vendor key ID range");
+MBEDTLS_STATIC_ASSERT(MBEDTLS_PSA_KEY_ID_BUILTIN_MIN < MBEDTLS_PSA_KEY_ID_BUILTIN_MAX,
+                      "Empty builtin key ID range");
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_VOLATILE_MIN < PSA_KEY_ID_VOLATILE_MAX,
+                      "Empty volatile key ID range");
+
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_USER_MAX < PSA_KEY_ID_VENDOR_MIN ||
+                      PSA_KEY_ID_VENDOR_MAX < PSA_KEY_ID_USER_MIN,
+                      "Overlap between user key IDs and vendor key IDs");
+
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_VENDOR_MIN <= MBEDTLS_PSA_KEY_ID_BUILTIN_MIN &&
+                      MBEDTLS_PSA_KEY_ID_BUILTIN_MAX <= PSA_KEY_ID_VENDOR_MAX,
+                      "Builtin key identifiers are not in the vendor range");
+
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_VENDOR_MIN <= PSA_KEY_ID_VOLATILE_MIN &&
+                      PSA_KEY_ID_VOLATILE_MAX <= PSA_KEY_ID_VENDOR_MAX,
+                      "Volatile key identifiers are not in the vendor range");
+
+MBEDTLS_STATIC_ASSERT(PSA_KEY_ID_VOLATILE_MAX < MBEDTLS_PSA_KEY_ID_BUILTIN_MIN ||
+                      MBEDTLS_PSA_KEY_ID_BUILTIN_MAX < PSA_KEY_ID_VOLATILE_MIN,
+                      "Overlap between builtin key IDs and volatile key IDs");
+
+
+
 typedef struct {
     psa_key_slot_t key_slots[MBEDTLS_PSA_KEY_SLOT_COUNT];
     unsigned key_slots_initialized : 1;