ssl_ticket.c: Base ticket age check on the ticket creation time

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit is contained in:
Ronald Cron 2023-11-22 10:00:14 +01:00
parent c57f86e132
commit 3c0072b58e
4 changed files with 62 additions and 28 deletions

View file

@ -1230,7 +1230,22 @@ struct mbedtls_ssl_session {
#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C) && \
defined(MBEDTLS_HAVE_TIME)
/*! Time in milliseconds when the ticket was created. */
/*! When a ticket is created by a TLS server as part of an established TLS
* session, the ticket creation time may need to be saved for the ticket
* module to be able to check the ticket age when the ticket is used.
* That's the purpose of this field.
* Before creating a new ticket, an Mbed TLS server set this field with
* its current time in milliseconds. This time may then be saved in the
* session ticket data by the session ticket writing function and
* recovered by the ticket parsing function later when the ticket is used.
* The ticket module may then use this time to compute the ticket age and
* determine if it has expired or not.
* The Mbed TLS implementations of the session ticket writing and parsing
* functions save and retrieve the ticket creation time as part of the
* session ticket data. The session ticket parsing function relies on
* the mbedtls_ssl_session_get_ticket_creation_time() API to get the
* ticket creation time from the session ticket data.
*/
mbedtls_ms_time_t MBEDTLS_PRIVATE(ticket_creation_time);
#endif
@ -2573,6 +2588,34 @@ void mbedtls_ssl_conf_session_tickets_cb(mbedtls_ssl_config *conf,
mbedtls_ssl_ticket_write_t *f_ticket_write,
mbedtls_ssl_ticket_parse_t *f_ticket_parse,
void *p_ticket);
#if defined(MBEDTLS_HAVE_TIME)
/**
* \brief Get the creation time of a session ticket.
*
* \note See the documentation of \c ticket_creation_time for information about
* the intended usage of this function.
*
* \param session SSL session
* \param ticket_creation_time On exit, holds the ticket creation time in
* milliseconds.
*
* \return 0 on success,
* MBEDTLS_ERR_SSL_BAD_INPUT_DATA if an input is not valid.
*/
static inline int mbedtls_ssl_session_get_ticket_creation_time(
mbedtls_ssl_session *session, mbedtls_ms_time_t *ticket_creation_time)
{
if (session == NULL || ticket_creation_time == NULL ||
session->MBEDTLS_PRIVATE(endpoint) != MBEDTLS_SSL_IS_SERVER) {
return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
}
*ticket_creation_time = session->MBEDTLS_PRIVATE(ticket_creation_time);
return 0;
}
#endif /* MBEDTLS_HAVE_TIME */
#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
/**

View file

@ -502,33 +502,22 @@ int mbedtls_ssl_ticket_parse(void *p_ticket,
}
#if defined(MBEDTLS_HAVE_TIME)
#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
if (session->tls_version == MBEDTLS_SSL_VERSION_TLS1_3) {
/* Check for expiration */
mbedtls_ms_time_t ticket_age = mbedtls_ms_time() -
session->ticket_creation_time;
mbedtls_ms_time_t ticket_lifetime =
(mbedtls_ms_time_t) ctx->ticket_lifetime * 1000;
mbedtls_ms_time_t ticket_creation_time, ticket_age;
mbedtls_ms_time_t ticket_lifetime =
(mbedtls_ms_time_t) ctx->ticket_lifetime * 1000;
if (ticket_age < 0 || ticket_age > ticket_lifetime) {
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
goto cleanup;
}
ret = mbedtls_ssl_session_get_ticket_creation_time(session,
&ticket_creation_time);
if (ret != 0) {
goto cleanup;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
if (session->tls_version == MBEDTLS_SSL_VERSION_TLS1_2) {
/* Check for expiration */
mbedtls_time_t current_time = mbedtls_time(NULL);
if (current_time < session->start ||
(uint32_t) (current_time - session->start) > key->lifetime) {
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
goto cleanup;
}
ticket_age = mbedtls_ms_time() - ticket_creation_time;
if (ticket_age < 0 || ticket_age > ticket_lifetime) {
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
goto cleanup;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
#endif /* MBEDTLS_HAVE_TIME */
#endif
cleanup:
#if defined(MBEDTLS_THREADING_C)

View file

@ -4282,6 +4282,9 @@ static int ssl_write_new_session_ticket(mbedtls_ssl_context *ssl)
* 10 . 9+n ticket content
*/
#if defined(MBEDTLS_HAVE_TIME)
ssl->session_negotiate->ticket_creation_time = mbedtls_ms_time();
#endif
if ((ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket,
ssl->session_negotiate,
ssl->out_msg + 10,

View file

@ -3140,10 +3140,6 @@ static int ssl_tls13_prepare_new_session_ticket(mbedtls_ssl_context *ssl,
MBEDTLS_SSL_DEBUG_MSG(2, ("=> prepare NewSessionTicket msg"));
#if defined(MBEDTLS_HAVE_TIME)
session->ticket_creation_time = mbedtls_ms_time();
#endif
/* Set ticket_flags depends on the advertised psk key exchange mode */
mbedtls_ssl_tls13_session_clear_ticket_flags(
session, MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK);
@ -3278,6 +3274,9 @@ static int ssl_tls13_write_new_session_ticket_body(mbedtls_ssl_context *ssl,
MBEDTLS_SSL_CHK_BUF_PTR(p, end, 4 + 4 + 1 + ticket_nonce_size + 2);
/* Generate ticket and ticket_lifetime */
#if defined(MBEDTLS_HAVE_TIME)
session->ticket_creation_time = mbedtls_ms_time();
#endif
ret = ssl->conf->f_ticket_write(ssl->conf->p_ticket,
session,
p + 9 + ticket_nonce_size + 2,