Use shims for two getters, and add a comment.

Author: egrimley-arm

src/c/shim.c

@@ -1,8 +1,24 @@
 // Copyright 2020 Contributors to the Parsec project.
 // SPDX-License-Identifier: Apache-2.0
 
+// This file is needed to provide linkable versions of certain
+// PSA Crypto functions that may be declared static inline.
+// See: https://github.com/ARMmbed/mbedtls/issues/3230
+
 #include "shim.h"
 
+size_t
+shim_get_key_bits(const psa_key_attributes_t *attributes)
+{
+    return psa_get_key_bits(attributes);
+}
+
+psa_key_type_t
+shim_get_key_type(const psa_key_attributes_t *attributes)
+{
+    return psa_get_key_type(attributes);
+}
+
 psa_key_attributes_t
 shim_key_attributes_init(void)
 {

src/c/shim.h

@@ -143,6 +143,12 @@ const psa_key_usage_t shim_PSA_KEY_USAGE_SIGN = PSA_KEY_USAGE_SIGN;
 const psa_key_usage_t shim_PSA_KEY_USAGE_VERIFY = PSA_KEY_USAGE_VERIFY;
 const psa_key_usage_t shim_PSA_KEY_USAGE_DERIVE = PSA_KEY_USAGE_DERIVE;
 
+size_t
+shim_get_key_bits(const psa_key_attributes_t *attributes);
+
+psa_key_type_t
+shim_get_key_type(const psa_key_attributes_t *attributes);
+
 psa_key_attributes_t
 shim_key_attributes_init(void);
 

src/lib.rs

@@ -229,14 +229,6 @@ pub fn psa_get_key_attributes(
     ))
 }
 
-pub fn psa_get_key_bits(attributes: &psa_key_attributes_t) -> usize {
-    wrap_any!((*attributes).x.core.bits as usize)
-}
-
-pub fn psa_get_key_type(attributes: &psa_key_attributes_t) -> psa_key_type_t {
-    wrap_any!((*attributes).x.core.type_)
-}
-
 pub fn psa_import_key(
     attributes: *const psa_key_attributes_t,
     data: *const u8,
@@ -263,6 +255,14 @@ pub fn psa_reset_key_attributes(attributes: *mut psa_key_attributes_t) {
 
 // Wrapped shims:
 
+pub fn psa_get_key_bits(attributes: &psa_key_attributes_t) -> usize {
+    wrap_any!(psa_crypto_binding::shim_get_key_bits(&attributes.x))
+}
+
+pub fn psa_get_key_type(attributes: &psa_key_attributes_t) -> psa_key_type_t {
+    wrap_any!(psa_crypto_binding::shim_get_key_type(&attributes.x))
+}
+
 pub fn psa_key_attributes_init() -> psa_key_attributes_t {
     let attr = wrap_any!(psa_crypto_binding::shim_key_attributes_init());
     psa_key_attributes_t { x: attr }