From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Mon, 22 Nov 2021 15:33:46 +0000 (+0100)
Subject: ntp: limit interleaved responses to NTPv4
X-Git-Tag: 4.2-pre1~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7f984cf7fa0eaaeb18557d84b4b8663d2436ec97;p=thirdparty%2Fchrony.git

ntp: limit interleaved responses to NTPv4

The interleaved modes are being specified for NTPv4 only. As a server,
detect interleaved requests only in NTPv4 packets.

Clients and peers can still send interleaved requests in lower-version
packets if configured with the version option.
---

diff --git a/ntp_core.c b/ntp_core.c
index fa2d5b25..a0ed6510 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -2395,7 +2395,8 @@ NCR_ProcessRxUnknown(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_a
      transmit timestamp (this is verified in transmit_packet()).  For a new
      client starting with a zero origin timestamp, the third response is the
      earliest one that can be interleaved. */
-  if (kod == 0 && log_index >= 0 && message->originate_ts.lo & htonl(1) &&
+  if (kod == 0 && log_index >= 0 && info.version == 4 &&
+      message->originate_ts.lo & htonl(1) &&
       UTI_CompareNtp64(&message->receive_ts, &message->transmit_ts) != 0) {
     ntp_rx = message->originate_ts;
     local_ntp_rx = &ntp_rx;