Update design document

- Support for PSA_CRYPTO_CLIENT without PSA_CRYPTO_C is out of scope for
now but might be added later (the architecture supports that).
- While we're using a void pointer for md_ctx, we don't need a union
here; the union will be useful only if & when we remove the indirection.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit is contained in:
Manuel Pégourié-Gonnard 2023-03-09 16:46:08 +01:00
parent 9b14639342
commit c9e0ad23c1

View File

@ -312,13 +312,16 @@ Note that some algorithms have different spellings in legacy and PSA. Since MD i
```
#if defined(MBEDTLS_MD_LIGHT)
#if defined(MBEDTLS_SHA256_C) || \
((defined(MBEDTLS_PSA_CRYPTO_C) || defined(MBEDTLS_PSA_CRYPTO_CLIENT)) && \
PSA_WANT_ALG_SHA_256)
(defined(MBEDTLS_PSA_CRYPTO_C) && PSA_WANT_ALG_SHA_256)
#define MBEDTLS_MD_CAN_SHA256
#endif
#endif
```
Note: in the future, we may want to replace `defined(MBEDTLS_PSA_CRYPTO_C)`
with `defined(MBEDTLS_PSA_CRYTO_C) || defined(MBEDTLS_PSA_CRYPTO_CLIENT)` but
for now this is out of scope.
#### MD light internal support macros
* If at least one hash has a PSA driver, define `MBEDTLS_MD_SOME_PSA`.
@ -337,16 +340,11 @@ enum {
} mbedtls_md_engine_t; // private type
typedef struct mbedtls_md_context_t {
const mbedtls_md_type_t type;
const mbedtls_md_engine_t engine;
union {
#if defined(MBEDTLS_MD_SOME_LEGACY)
void *legacy; // used if engine == LEGACY
#endif
mbedtls_md_type_t type;
#if defined(MBEDTLS_MD_SOME_PSA)
psa_hash_operation_t *psa; // used if engine == PSA
mbedtls_md_engine_t engine;
#endif
} digest;
void *md_ctx; // mbedtls_xxx_context or psa_hash_operation
#if defined(MBEDTLS_MD_C)
void *hmac_ctx;
#endif