Start detecting epoch 0 ClientHellos

This commit is contained in:
Manuel Pégourié-Gonnard 2015-09-04 12:58:55 +02:00
parent 26d227ddfc
commit 9650205df7

View file

@ -3343,11 +3343,33 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 1, ( "record from another epoch: "
"expected %d, received %d",
ssl->in_epoch, rec_epoch ) );
#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && \
defined(MBEDTLS_SSL_SRV_C)
/*
* Check for an epoch 0 ClientHello. We can't use in_msg here to
* access the first byte of record content (handshake type), as we
* have an active transform (possibly iv_len != 0), so use the
* fact that the record header len is 13 instead.
*/
if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
rec_epoch == 0 &&
ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
ssl->in_left > 13 &&
ssl->in_buf[13] == MBEDTLS_SSL_HS_CLIENT_HELLO )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "possible client reconnect "
"from the same port" ) );
}
else
#endif /* MBEDTLS_SSL_DLTS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */
return( MBEDTLS_ERR_SSL_INVALID_RECORD );
}
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
/* Replay detection only works for the current epoch */
if( rec_epoch == ssl->in_epoch &&
mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record" ) );
return( MBEDTLS_ERR_SSL_INVALID_RECORD );