Introduce MD handle type
As has been previously done for ciphersuites, this commit introduces
a zero-cost abstraction layer around the type
mbedtls_md_info const *
whose valid values represent implementations of message digest algorithms.
Access to a particular digest implementation can be requested by name or
digest ID through the API mbedtls_md_info_from_xxx(), which either returns
a valid implementation or NULL, representing failure.
This commit replaces such uses of `mbedtls_md_info const *` by an abstract
type `mbedtls_md_handle_t` whose valid values represent digest implementations,
and which has a designated invalid value MBEDTLS_MD_INVALID_HANDLE.
The purpose of this abstraction layer is to pave the way for builds which
support precisely one digest algorithm. In this case, mbedtls_md_handle_t
can be implemented as a two-valued type, with one value representing the
invalid handle, and the unique valid value representing the unique enabled
digest.
diff --git a/library/x509.c b/library/x509.c
index 19cc64b..ec83017 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -1065,7 +1065,7 @@
if( pk_alg == MBEDTLS_PK_RSASSA_PSS )
{
const mbedtls_pk_rsassa_pss_options *pss_opts;
- const mbedtls_md_info_t *md_info, *mgf_md_info;
+ mbedtls_md_handle_t md_info, mgf_md_info;
pss_opts = (const mbedtls_pk_rsassa_pss_options *) sig_opts;