Allow defining MD information structs through macros
In builds enabling only a single MD digest, we want to be able to
implement the MD info getter functions by returning compile-time
constants matching the fields of the MD info structures used so far.
To avoid information duplication hardening maintainability, this
commit introduces the possibility of providing the various aspects
of a particular digest implementation by defining macros
MBEDTLS_MD_INFO_DIGEST_FIELD (e.g. MBEDTLS_MD_INFO_SHA256_SIZE)
and to generate the corresponding mbedtls_md_info instance from
this set of macros, via the new macro MBEDTLS_MD_INFO().
This way, we'll be able to switch between MD info based builds
and single-digest builds without information duplication.
diff --git a/include/mbedtls/md_internal.h b/include/mbedtls/md_internal.h
index 72a8e46..43ee48f 100644
--- a/include/mbedtls/md_internal.h
+++ b/include/mbedtls/md_internal.h
@@ -40,6 +40,59 @@
extern "C" {
#endif
+/*
+ * Message-digest information macro definition
+ */
+
+/* SHA-256 */
+#define MBEDTLS_MD_INFO_SHA256_TYPE MBEDTLS_MD_SHA256
+#define MBEDTLS_MD_INFO_SHA256_NAME "SHA256"
+#define MBEDTLS_MD_INFO_SHA256_SIZE 32
+#define MBEDTLS_MD_INFO_SHA256_BLOCKSIZE 64
+#define MBEDTLS_MD_INFO_SHA256_STARTS_FUNC sha256_starts_wrap
+#define MBEDTLS_MD_INFO_SHA256_UPDATE_FUNC sha224_update_wrap
+#define MBEDTLS_MD_INFO_SHA256_FINISH_FUNC sha224_finish_wrap
+#define MBEDTLS_MD_INFO_SHA256_DIGEST_FUNC sha256_wrap
+#define MBEDTLS_MD_INFO_SHA256_ALLOC_FUNC sha224_ctx_alloc
+#define MBEDTLS_MD_INFO_SHA256_FREE_FUNC sha224_ctx_free
+#define MBEDTLS_MD_INFO_SHA256_CLONE_FUNC sha224_clone_wrap
+#define MBEDTLS_MD_INFO_SHA256_PROCESS_FUNC sha224_process_wrap
+
+/*
+ * Helper macros to extract fields from ciphersuites.
+ */
+
+#define MBEDTLS_MD_INFO_TYPE_T( MD ) MD ## _TYPE
+#define MBEDTLS_MD_INFO_NAME_T( MD ) MD ## _NAME
+#define MBEDTLS_MD_INFO_SIZE_T( MD ) MD ## _SIZE
+#define MBEDTLS_MD_INFO_BLOCKSIZE_T( MD ) MD ## _BLOCKSIZE
+#define MBEDTLS_MD_INFO_STARTS_FUNC_T( MD ) MD ## _STARTS_FUNC
+#define MBEDTLS_MD_INFO_UPDATE_FUNC_T( MD ) MD ## _UPDATE_FUNC
+#define MBEDTLS_MD_INFO_FINISH_FUNC_T( MD ) MD ## _FINISH_FUNC
+#define MBEDTLS_MD_INFO_DIGEST_FUNC_T( MD ) MD ## _DIGEST_FUNC
+#define MBEDTLS_MD_INFO_ALLOC_FUNC_T( MD ) MD ## _ALLOC_FUNC
+#define MBEDTLS_MD_INFO_FREE_FUNC_T( MD ) MD ## _FREE_FUNC
+#define MBEDTLS_MD_INFO_CLONE_FUNC_T( MD ) MD ## _CLONE_FUNC
+#define MBEDTLS_MD_INFO_PROCESS_FUNC_T( MD ) MD ## _PROCESS_FUNC
+
+/* Wrapper around MBEDTLS_MD_INFO_XXX_T() which makes sure that
+ * the argument is macro-expanded before concatenated with the
+ * field name. This allows to call these macros as
+ * MBEDTLS_MD_INFO_XXX( MBEDTLS_SSL_CONF_SINGLE_HASH ).
+ * where MBEDTLS_SSL_CONF_SINGLE_HASH expands to MBEDTLS_MD_INFO_XXX. */
+#define MBEDTLS_MD_INFO_TYPE( MD ) MBEDTLS_MD_INFO_TYPE_T( MD )
+#define MBEDTLS_MD_INFO_NAME( MD ) MBEDTLS_MD_INFO_NAME_T( MD )
+#define MBEDTLS_MD_INFO_SIZE( MD ) MBEDTLS_MD_INFO_SIZE_T( MD )
+#define MBEDTLS_MD_INFO_BLOCKSIZE( MD ) MBEDTLS_MD_INFO_BLOCKSIZE_T( MD )
+#define MBEDTLS_MD_INFO_STARTS_FUNC( MD ) MBEDTLS_MD_INFO_STARTS_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_UPDATE_FUNC( MD ) MBEDTLS_MD_INFO_UPDATE_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_FINISH_FUNC( MD ) MBEDTLS_MD_INFO_FINISH_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_DIGEST_FUNC( MD ) MBEDTLS_MD_INFO_DIGEST_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_ALLOC_FUNC( MD ) MBEDTLS_MD_INFO_ALLOC_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_FREE_FUNC( MD ) MBEDTLS_MD_INFO_FREE_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_CLONE_FUNC( MD ) MBEDTLS_MD_INFO_CLONE_FUNC_T( MD )
+#define MBEDTLS_MD_INFO_PROCESS_FUNC( MD ) MBEDTLS_MD_INFO_PROCESS_FUNC_T( MD )
+
/**
* Message digest information.
* Allows message digest functions to be called in a generic way.
@@ -98,6 +151,24 @@
mbedtls_md_process_func_t *process_func;
};
+/**
+ * \brief This macro builds an instance of ::mbedtls_md_info_t
+ * from an \c MBEDTLS_MD_INFO_XXX identifier.
+ */
+#define MBEDTLS_MD_INFO( MD ) \
+ { MBEDTLS_MD_INFO_TYPE( MD ), \
+ MBEDTLS_MD_INFO_NAME( MD ), \
+ MBEDTLS_MD_INFO_SIZE( MD ), \
+ MBEDTLS_MD_INFO_BLOCKSIZE( MD ), \
+ MBEDTLS_MD_INFO_STARTS_FUNC( MD ), \
+ MBEDTLS_MD_INFO_UPDATE_FUNC( MD ), \
+ MBEDTLS_MD_INFO_FINISH_FUNC( MD ), \
+ MBEDTLS_MD_INFO_DIGEST_FUNC( MD ), \
+ MBEDTLS_MD_INFO_ALLOC_FUNC( MD ), \
+ MBEDTLS_MD_INFO_FREE_FUNC( MD ), \
+ MBEDTLS_MD_INFO_CLONE_FUNC( MD ), \
+ MBEDTLS_MD_INFO_PROCESS_FUNC( MD ) }
+
/*
* Getter functions for MD info structure.
*/