check_config.h: make TLS1.3 requirements verification more readable
#endif
/* TLS 1.3 requires at least one ciphersuite, so at least SHA-256 or SHA-384 */
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
- !( ( defined(PSA_WANT_ALG_SHA_256) || defined(PSA_WANT_ALG_SHA_348) ) && \
- ( defined(MBEDTLS_USE_PSA_CRYPTO) || ( defined(MBEDTLS_MD_C) && ( defined(MBEDTLS_SHA256_C) || defined(MBEDTLS_SHA384_C) ) ) ) )
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+/* We always need at least one of the hashes via PSA (for use with HKDF) */
+#if !( defined(PSA_WANT_ALG_SHA_256) || defined(PSA_WANT_ALG_SHA_384) )
#error "MBEDTLS_SSL_PROTO_TLS1_3 defined, but not all prerequisites"
-#endif
+#endif /* !(PSA_WANT_ALG_SHA_256 || PSA_WANT_ALG_SHA_384) */
+#if !defined(MBEDTLS_USE_PSA_CRYPTO)
+/* When USE_PSA_CRYPTO is not defined, we also need SHA-256 or SHA-384 via the
+ * legacy interface, including via the MD layer, for the parts of the code
+ * that are shared with TLS 1.2 (running handshake hash). */
+#if !defined(MBEDTLS_MD_C) || \
+ !( defined(MBEDTLS_SHA256_C) || defined(MBEDTLS_SHA384_C) )
+#error "MBEDTLS_SSL_PROTO_TLS1_3 defined, but not all prerequisites"
+#endif /* !MBEDTLS_MD_C || !(MBEDTLS_SHA256_C || MBEDTLS_SHA384_C) */
+#endif /* !MBEDTLS_USE_PSA_CRYPTO */
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
/*
* The current implementation of TLS 1.3 requires MBEDTLS_SSL_KEEP_PEER_CERTIFICATE.
