crypto: se05x: improve object deletion logs

For SE05x, only private keys are stored in the secure element: the
OP-TEE secure storage REE/RPMB retains the full public key but just a
handle to the private key.

If the secure element's persistent storage is erased, but OP-TEE's
secure storage remains, the public key can still be accessed while the
private key is inaccessible. However, in such cases, the 'key' will
still appear as present in the PKCS#11 database.

When CFG_CORE_SE05X_BLOCK_OBJ_DEL_ON_ERROR is enabled (not by default)
and the key pointed to by the handle is not present in the secure
element, OP-TEE PKCS#11 clients will encounter an error when attempting
to delete the private key information held in the OP-TEE secure
storage.

If the setting is disabled, the PKCS#11 storage clears the
private key handle without errors.

This commit removes some ambiguity, so users do not see error messages
when operations complete successfully.

It also fails on sss_se05x_key_object_init errors unconditionally since
a failure on this function can only signify some form of stack
corruption.

Signed-off-by: Jorge Ramirez-Ortiz <[email protected]>

core/drivers/crypto/se050/core/storage.c

@@ -71,21 +71,21 @@ TEE_Result crypto_storage_obj_del(struct tee_obj *o)
 		return TEE_SUCCESS;
 
 	status = sss_se05x_key_object_init(&k_object, se050_kstore);
-	if (status != kStatus_SSS_Success) {
-		ret = TEE_ERROR_BAD_STATE;
-		goto out;
-	}
+	if (status != kStatus_SSS_Success)
+		return TEE_ERROR_BAD_STATE;
 
 	status = sss_se05x_key_object_get_handle(&k_object, val);
 	if (status != kStatus_SSS_Success) {
-		EMSG("se05x: can not communicate with the secure element");
+		if (IS_ENABLED(CFG_CORE_SE05X_BLOCK_OBJ_DEL_ON_ERROR))
+			EMSG("se05x: key not found in secure element");
 		ret = TEE_ERROR_BAD_STATE;
 		goto out;
 	}
 
 	status = sss_se05x_key_store_erase_key(se050_kstore, &k_object);
 	if (status != kStatus_SSS_Success) {
-		EMSG("se05x: can not communicate with the secure element");
+		if (IS_ENABLED(CFG_CORE_SE05X_BLOCK_OBJ_DEL_ON_ERROR))
+			EMSG("se05x: key can't be removed from secure element");
 		ret = TEE_ERROR_BAD_STATE;
 		goto out;
 	}