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.
This commit is contained in:
Hanno Becker 2019-07-17 11:21:02 +01:00
parent 505be8be4d
commit a5cedbcd3f
30 changed files with 247 additions and 177 deletions

View file

@ -1065,7 +1065,7 @@ int mbedtls_x509_sig_alg_gets( char *buf, size_t size, mbedtls_pk_type_t pk_alg,
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;