Document another limitation of driver-only hashes
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/ChangeLog.d/driver-only-hashes.txt b/ChangeLog.d/driver-only-hashes.txt
index 2062bcb..a160f92 100644
--- a/ChangeLog.d/driver-only-hashes.txt
+++ b/ChangeLog.d/driver-only-hashes.txt
@@ -8,12 +8,16 @@
are only provided by PSA drivers. In these configurations, you need to
call `psa_crypto_init()` before you call any function from those
modules; this is not required in configurations where the built-in
- implementation is still available. Note that some crypto modules and
- features still depend on the built-in implementation of hashes:
- MBEDTLS_HKDF_C (but the PSA HKDF function do not depend on it),
- MBEDTLS_ENTROPY_C, MBEDTLS_HMAC_DRBG_C and MBEDTLS_ECDSA_DETERMINISTIC.
- In particular, for now, compiling without built-in hashes requires use
- of MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG.
+ implementation is still available. Note that for modules that use MD
+ (RSA, PKCS5, PKCS12, EC J-PAKE) in builds that have MBEDTLS_MD_C enabled,
+ all hashes used with those modules need to be built-in, as drivers are only
+ used when MBEDTLS_MD_C is disabled; configurations where some hashes are
+ available as built-ins, and some only from drivers, are currently not
+ supported. Also note that some crypto modules and features still depend on
+ the built-in implementation of hashes: MBEDTLS_HKDF_C (but the PSA HKDF
+ functions do not depend on it), MBEDTLS_ENTROPY_C, MBEDTLS_HMAC_DRBG_C and
+ MBEDTLS_ECDSA_DETERMINISTIC. In particular, for now, compiling without
+ built-in hashes requires use of MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG.
* When MBEDTLS_USE_PSA_CRYPTO is enabled, X.509, TLS 1.2 and TLS 1.3 no
longer depend on MD. This means it is now possible to use them in
configurations where the built-in implementations of hashes are excluded
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 3f869b9..b16a5b4 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1146,6 +1146,11 @@
* \warning If building without MBEDTLS_MD_C, you must call psa_crypto_init()
* before doing any PKCS#1 v2.1 operation.
*
+ * \warning When building with MBEDTLS_MD_C, all hashes used with this
+ * need to be available a built-ins (that is, for SHA-256, MBEDTLS_SHA256_C,
+ * etc.) as opposed to just PSA drivers. So far, PSA drivers are only used by
+ * this module in builds where MBEDTLS_MD_C is disabled.
+ *
* This enables support for RSAES-OAEP and RSASSA-PSS operations.
*/
#define MBEDTLS_PKCS1_V21
@@ -2433,6 +2438,11 @@
*
* \warning If building without MBEDTLS_MD_C, you must call psa_crypto_init()
* before doing any EC J-PAKE operations.
+ *
+ * \warning When building with MBEDTLS_MD_C, all hashes used with this
+ * need to be available a built-ins (that is, for SHA-256, MBEDTLS_SHA256_C,
+ * etc.) as opposed to just PSA drivers. So far, PSA drivers are only used by
+ * this module in builds where MBEDTLS_MD_C is disabled.
*/
#define MBEDTLS_ECJPAKE_C
@@ -2777,6 +2787,11 @@
* \warning If building without MBEDTLS_MD_C, you must call psa_crypto_init()
* before doing any PKCS5 operation.
*
+ * \warning When building with MBEDTLS_MD_C, all hashes used with this
+ * need to be available a built-ins (that is, for SHA-256, MBEDTLS_SHA256_C,
+ * etc.) as opposed to just PSA drivers. So far, PSA drivers are only used by
+ * this module in builds where MBEDTLS_MD_C is disabled.
+ *
* This module adds support for the PKCS#5 functions.
*/
#define MBEDTLS_PKCS5_C
@@ -2796,6 +2811,11 @@
* \warning If building without MBEDTLS_MD_C, you must call psa_crypto_init()
* before doing any PKCS12 operation.
*
+ * \warning When building with MBEDTLS_MD_C, all hashes used with this
+ * need to be available a built-ins (that is, for SHA-256, MBEDTLS_SHA256_C,
+ * etc.) as opposed to just PSA drivers. So far, PSA drivers are only used by
+ * this module in builds where MBEDTLS_MD_C is disabled.
+ *
* This module enables PKCS#12 functions.
*/
#define MBEDTLS_PKCS12_C