psa_key_slot_t: different fields in free vs occupied slots
Place some fields of psa_key_slot_t in a union, to prepare for a new field
in free slots that should not require extra memory.
For occupied slots, place only the registered_readers field in the union,
not other fields, to minimize textual changes. All fields could move to the
union except state (also needed in free slots) and attr (which must stay
first to reduce the code size, because it is accessed at many call sites).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index 7e0a1c1..327be0a 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -268,7 +268,7 @@
for (size_t slice_idx = 0; slice_idx < KEY_SLICE_COUNT; slice_idx++) {
for (size_t slot_idx = 0; slot_idx < key_slice_length(slice_idx); slot_idx++) {
psa_key_slot_t *slot = get_key_slot(slice_idx, slot_idx);
- slot->registered_readers = 1;
+ slot->var.occupied.registered_readers = 1;
slot->state = PSA_SLOT_PENDING_DELETION;
(void) psa_wipe_key_slot(slot);
}
@@ -568,12 +568,12 @@
/* If we are the last reader and the slot is marked for deletion,
* we must wipe the slot here. */
if ((slot->state == PSA_SLOT_PENDING_DELETION) &&
- (slot->registered_readers == 1)) {
+ (slot->var.occupied.registered_readers == 1)) {
return psa_wipe_key_slot(slot);
}
if (psa_key_slot_has_readers(slot)) {
- slot->registered_readers--;
+ slot->var.occupied.registered_readers--;
return PSA_SUCCESS;
}
@@ -707,7 +707,7 @@
return status;
}
- if (slot->registered_readers == 1) {
+ if (slot->var.occupied.registered_readers == 1) {
status = psa_wipe_key_slot(slot);
} else {
status = psa_unregister_read(slot);
@@ -742,7 +742,7 @@
}
if ((!PSA_KEY_LIFETIME_IS_VOLATILE(slot->attr.lifetime)) &&
- (slot->registered_readers == 1)) {
+ (slot->var.occupied.registered_readers == 1)) {
status = psa_wipe_key_slot(slot);
} else {
status = psa_unregister_read(slot);