tls13: early_data: cli: improve comment

This commit improves comment of the check for handshake parameters
in Encrypted Extension.

Signed-off-by: Yanray Wang <yanray.wang@arm.com>
This commit is contained in:
Yanray Wang 2023-12-01 17:40:19 +08:00
parent e72dfff1d6
commit 03a00768c0

View file

@ -2182,14 +2182,15 @@ static int ssl_tls13_process_encrypted_extensions(mbedtls_ssl_context *ssl)
* - The selected cipher suite
* - The selected ALPN [RFC7301] protocol, if any
*
* When parsing EncryptedExtensions, the client does not know if
* the server will accept early data and select the first proposed
* pre-shared key with a cipher suite that is different from the
* cipher suite associated to the selected pre-shared key. To address
* aforementioned case, when early data is involved, we check:
* - the selected pre-shared key is the first proposed one
* - the selected cipher suite same as the one associated with the
* pre-shared key.
* The server has sent an early data extension in its Encrypted
* Extension message thus accepted to receive early data. We
* check here that the additional constraints on the handshake
* parameters, when early data are exchanged, are met,
* namely:
* - the selected PSK for the handshake was the first one proposed
* by the client.
* - the selected ciphersuite for the handshake is the ciphersuite
* associated with the selected PSK.
*/
if (handshake->selected_identity != 0 ||
handshake->ciphersuite_info->id !=