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fix ticket age check issues

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- Ticket age and ticket age add, obfuscated age
  use different unit. Align the units to million
  seconds.
- Add maximum ticket age check. Until now,
  ticket_lifetime is not recorded in server side.
  Check it with maximum ticket_lifetime.
- Free session when error found.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
This commit is contained in:
Jerry Yu 2022-09-13 14:15:48 +08:00
parent 46bffe0e82
commit 8d4bbbae4f
1 changed files with 66 additions and 42 deletions
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108
library/ssl_tls13_server.c
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@ -127,13 +127,17 @@ static int ssl_tls13_parse_key_exchange_modes_ext( mbedtls_ssl_context *ssl,
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_offered_psks_check_identity_match_ticket(
mbedtls_ssl_context *ssl,
mbedtls_ssl_session *session,
const unsigned char *identity,
size_t identity_len,
uint32_t obfuscated_ticket_age )
uint32_t obfuscated_ticket_age,
mbedtls_ssl_session *session )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *ticket_buffer;
#if defined(MBEDTLS_HAVE_TIME)
mbedtls_time_t now;
uint64_t age_in_s, age_in_ms, client_age_in_ms;
#endif
((void) obfuscated_ticket_age);
@ -178,49 +182,70 @@ static int ssl_tls13_offered_psks_check_identity_match_ticket(
/* We delete the temporary buffer */
mbedtls_free( ticket_buffer );
if( ret == 0 )
if( ret != 0 )
goto exit;
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
#if defined(MBEDTLS_HAVE_TIME)
now = mbedtls_time( NULL );
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
if( now < session->start )
{
#if defined(MBEDTLS_HAVE_TIME)
mbedtls_time_t now;
int64_t diff;
#endif
ret = SSL_TLS1_3_OFFERED_PSK_MATCH;
#if defined(MBEDTLS_HAVE_TIME)
now = mbedtls_time( NULL );
MBEDTLS_SSL_DEBUG_MSG(
3, ( "Ticket expired: now=%" MBEDTLS_PRINTF_LONGLONG
", start=%" MBEDTLS_PRINTF_LONGLONG,
(long long)now, (long long)session->start ) );
goto exit;
}
/* Check #1:
* Is the time when the ticket was issued later than now?
*/
if( now < session->start )
{
MBEDTLS_SSL_DEBUG_MSG(
3, ( "Ticket expired: now=%" MBEDTLS_PRINTF_LONGLONG
", start=%" MBEDTLS_PRINTF_LONGLONG,
(long long)now, (long long)session->start ) );
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
}
age_in_s = (uint64_t)( now - session->start );
/* Check #2:
* Is the ticket age for the selected PSK identity
* (computed by subtracting ticket_age_add from
* PskIdentity.obfuscated_ticket_age modulo 2^32 )
* within a small tolerance of the time since the
* ticket was issued?
*/
diff = ( now - session->start ) -
( obfuscated_ticket_age - session->ticket_age_add );
/* RFC 8446 section 4.6.1
*
* Servers MUST NOT use any value greater than 604800 seconds (7 days).
*
* RFC 8446 section 4.2.11.1
*
* Clients MUST NOT attempt to use tickets which have ages greater than
* the "ticket_lifetime" value which was provided with the ticket.
*
* For time being, the age MUST be less than 604800 seconds (7 days).
*/
if( age_in_s > 604800 )
{
MBEDTLS_SSL_DEBUG_MSG(
3, ( "Ticket expired: Ticket age exceed limitation ticket_age=%lu",
(long unsigned int)age_in_s ) );
goto exit;
}
if( diff > MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE )
{
MBEDTLS_SSL_DEBUG_MSG( 3,
( "Ticket age outside tolerance window ( diff=%"
MBEDTLS_PRINTF_LONGLONG" )",
(long long)diff ) );
ret = MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
}
/* RFC 8446 section 4.2.10
*
* For PSKs provisioned via NewSessionTicket, a server MUST validate that
* the ticket age for the selected PSK identity (computed by subtracting
* ticket_age_add from PskIdentity.obfuscated_ticket_age modulo 2^32) is
* within a small tolerance of the time since the ticket was issued.
*/
age_in_ms = age_in_s * 1000;
client_age_in_ms = obfuscated_ticket_age - session->ticket_age_add;
if( age_in_ms < client_age_in_ms ||
( age_in_ms - client_age_in_ms ) > MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE )
{
MBEDTLS_SSL_DEBUG_MSG(
3, ( "Ticket expired: Ticket age outside tolerance window "
"( diff=%d )",
(int)(age_in_ms - client_age_in_ms ) ) );
goto exit;
}
ret = 0;
#endif /* MBEDTLS_HAVE_TIME */
}
exit:
if( ret != 0 )
mbedtls_ssl_session_free( session );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= check_identity_match_ticket" ) );
return( ret );
@ -247,9 +272,8 @@ static int ssl_tls13_offered_psks_check_identity_match(
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
if( ssl_tls13_offered_psks_check_identity_match_ticket(
ssl, (mbedtls_ssl_session *)session,
identity, identity_len,
obfuscated_ticket_age ) == SSL_TLS1_3_OFFERED_PSK_MATCH )
ssl, identity, identity_len, obfuscated_ticket_age,
(mbedtls_ssl_session *)session ) == SSL_TLS1_3_OFFERED_PSK_MATCH )
{
mbedtls_ssl_session *i_session=(mbedtls_ssl_session *)session;
ssl->handshake->resume = 1;