Skip generating early secrets in some cases

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>
This commit is contained in:
Xiaokang Qian 2023-01-04 08:43:46 +00:00
parent b46275c7ec
commit 303f82c5b9

View File

@ -1901,15 +1901,21 @@ static int ssl_tls13_postprocess_server_hello(mbedtls_ssl_context *ssl)
/* Start the TLS 1.3 key schedule: Set the PSK and derive early secret.
*
* TODO: We don't have to do this in case we offered 0-RTT and the
* server accepted it. In this case, we could skip generating
* the early secret. */
* We do this in case we didn't offer 0-RTT or even we offered 0-RTT but
* server selected ephemeral mode. In other cases, we could skip generating
* the early secret.
*/
if ((ssl->early_data_status == MBEDTLS_SSL_EARLY_DATA_STATUS_NOT_SENT)
|| ((ssl->early_data_status == MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED)
&& handshake->key_exchange_mode ==
MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL)) {
ret = mbedtls_ssl_tls13_key_schedule_stage_early(ssl);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_tls13_key_schedule_stage_early",
ret);
MBEDTLS_SSL_DEBUG_RET(
1, "mbedtls_ssl_tls13_key_schedule_stage_early", ret);
goto cleanup;
}
}
ret = mbedtls_ssl_tls13_compute_handshake_transform(ssl);
if (ret != 0) {