commit 97bb726e2d4d5c1864f3e20cef12284060f66459
author Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Mon Sep 18 11:28:32 2023 +0200
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Mon Sep 18 11:28:32 2023 +0200
tree 1f71c22d5478d101b572b5d686584774c62b08df
parent 275afe187f06f6cb05414c58f7aceab63f69d0a4

Add clarifying comment

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>

include/mbedtls/ssl_ciphersuites.h

diff --git a/include/mbedtls/ssl_ciphersuites.h b/include/mbedtls/ssl_ciphersuites.h
index 62c138d..a707132 100644
--- a/include/mbedtls/ssl_ciphersuites.h
+++ b/include/mbedtls/ssl_ciphersuites.h
@@ -304,13 +304,21 @@
 #define MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED
 #endif
 
-/* Key exchanges allowing client certificate requests */
+/* Key exchanges allowing client certificate requests.
+ *
+ * Note: that's almost the same as MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED
+ * above, except RSA-PSK uses a server certificate but no client cert.
+ *
+ * Note: this difference is specific to TLS 1.2, as with TLS 1.3, things are
+ * more symmetrical: client certs and server certs are either both allowed
+ * (Ephemeral mode) or both disallowed (PSK and PKS-Ephemeral modes).
+ */
 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)           ||       \
     defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)       ||       \
-    defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)      ||       \
     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED)     ||       \
+    defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)   ||       \
     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)    ||       \
-    defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+    defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)
 #define MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED
 #endif