From ac0b28cce687e97d5889cdaf06480df16843125d Mon Sep 17 00:00:00 2001 From: Miroslav Lichvar Date: Thu, 12 Jan 2017 12:21:50 +0100 Subject: [PATCH] sourcestats: align sample time used for source report This reduces leak of sample times (and receive timestamps which are related to sample times), which could be useful in off-path attacks on unauthenticated symmetric interleaved mode. --- sourcestats.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/sourcestats.c b/sourcestats.c index 27e6ce3..52c0314 100644 --- a/sourcestats.c +++ b/sourcestats.c @@ -928,7 +928,7 @@ void SST_DoSourceReport(SST_Stats inst, RPT_SourceReport *report, struct timespec *now) { int i, j; - struct timespec ago; + struct timespec last_sample_time; if (inst->n_samples > 0) { i = get_runsbuf_index(inst, inst->n_samples - 1); @@ -938,8 +938,10 @@ SST_DoSourceReport(SST_Stats inst, RPT_SourceReport *report, struct timespec *no report->latest_meas_err = 0.5*inst->root_delays[j] + inst->root_dispersions[j]; report->stratum = inst->strata[j]; - UTI_DiffTimespecs(&ago, now, &inst->sample_times[i]); - report->latest_meas_ago = ago.tv_sec; + /* Align the sample time to reduce the leak of the receive timestamp */ + last_sample_time = inst->sample_times[i]; + last_sample_time.tv_nsec = 0; + report->latest_meas_ago = UTI_DiffTimespecsToDouble(now, &last_sample_time); } else { report->latest_meas_ago = (uint32_t)-1; report->orig_latest_meas = 0;