commit 972539c2418c751d5974717c097d8667a16c7e5f
author Gilles Peskine <Gilles.Peskine@arm.com> Wed Feb 28 01:49:45 2024 +0100
committer Gilles Peskine <Gilles.Peskine@arm.com> Wed Feb 28 01:49:45 2024 +0100
tree 30335eee314e8728dda19d03c73d252d4a728b02
parent 2dc2bd70972710b44172007d560495d1191fb23b

In attributes, keep track of slot number through a dedicated field

In `psa_key_attributes_t`, keep track of whether `slot_number` has been set
through a dedicated field, rather than using a flag.

This paves the way to removing `flags`, which is not used for anything else.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

include/psa/crypto_extra.h

diff --git a/include/psa/crypto_extra.h b/include/psa/crypto_extra.h
index d94e946..6ed1f6c 100644
--- a/include/psa/crypto_extra.h
+++ b/include/psa/crypto_extra.h
@@ -129,7 +129,7 @@
     psa_key_attributes_t *attributes,
     psa_key_slot_number_t slot_number)
 {
-    attributes->MBEDTLS_PRIVATE(flags) |= MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
+    attributes->MBEDTLS_PRIVATE(has_slot_number) = 1;
     attributes->MBEDTLS_PRIVATE(slot_number) = slot_number;
 }
 
@@ -142,8 +142,7 @@
 static inline void psa_clear_key_slot_number(
     psa_key_attributes_t *attributes)
 {
-    attributes->MBEDTLS_PRIVATE(flags) &=
-        ~MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER;
+    attributes->MBEDTLS_PRIVATE(has_slot_number) = 0;
 }
 
 /** Register a key that is already present in a secure element.

include/psa/crypto_struct.h

diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index adb33ed..e8f67d5 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -292,6 +292,7 @@
 struct psa_key_attributes_s {
 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
     psa_key_slot_number_t MBEDTLS_PRIVATE(slot_number);
+    int MBEDTLS_PRIVATE(has_slot_number);
 #endif /* MBEDTLS_PSA_CRYPTO_SE_C */
     psa_key_type_t MBEDTLS_PRIVATE(type);
     psa_key_bits_t MBEDTLS_PRIVATE(bits);
@@ -313,7 +314,7 @@
 };
 
 #if defined(MBEDTLS_PSA_CRYPTO_SE_C)
-#define PSA_KEY_ATTRIBUTES_MAYBE_SLOT_NUMBER 0,
+#define PSA_KEY_ATTRIBUTES_MAYBE_SLOT_NUMBER 0, 0,
 #else
 #define PSA_KEY_ATTRIBUTES_MAYBE_SLOT_NUMBER
 #endif

library/psa_crypto.c

diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 71535fa..91f5f16 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1245,7 +1245,7 @@
     const psa_key_attributes_t *attributes,
     psa_key_slot_number_t *slot_number)
 {
-    if (attributes->flags & MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER) {
+    if (attributes->has_slot_number) {
         *slot_number = attributes->slot_number;
         return PSA_SUCCESS;
     } else {