Check if key domain is not already initialized when initializing.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/hsm/cmd_key_domain.c

@@ -103,6 +103,9 @@ int cmd_key_domain() {
         uint8_t t[MAX_KEY_DOMAINS * 2];
         memcpy(t, kdata, tf_kd_size);
         if (p1 == 0x1) {
+            if (t[2 * p2] != 0xff && t[2 * p2 + 1] != 0xff) {
+                return SW_INCORRECT_P1P2();
+            }
             t[2 * p2] = dkeks = apdu.data[0];
             t[2 * p2 + 1] = current_dkeks = 0;
         }