diff -up ntp-4.2.6p5/ntpd/ntp_proto.c.cve-2016-7426 ntp-4.2.6p5/ntpd/ntp_proto.c
--- ntp-4.2.6p5/ntpd/ntp_proto.c.cve-2016-7426 2016-11-21 16:14:42.804048665 +0100
+++ ntp-4.2.6p5/ntpd/ntp_proto.c 2016-11-21 17:32:45.619107824 +0100
@@ -473,30 +473,7 @@ receive(
}
/*
- * Update the MRU list and finger the cloggers. It can be a
- * little expensive, so turn it off for production use.
- */
- restrict_mask = ntp_monitor(rbufp, restrict_mask);
- if (restrict_mask & RES_LIMITED) {
- sys_limitrejected++;
- if (!(restrict_mask & RES_KOD) || MODE_BROADCAST ==
- hismode || MODE_SERVER == hismode)
- return; /* rate exceeded */
-
- if (hismode == MODE_CLIENT)
- fast_xmit(rbufp, MODE_SERVER, skeyid,
- restrict_mask);
- else
- fast_xmit(rbufp, MODE_ACTIVE, skeyid,
- restrict_mask);
- return; /* rate exceeded */
- }
- restrict_mask &= ~RES_KOD;
-
- /*
- * We have tossed out as many buggy packets as possible early in
- * the game to reduce the exposure to a clogging attack. now we
- * have to burn some cycles to find the association and
+ * now we have to burn some cycles to find the association and
* authenticate the packet if required. Note that we burn only
* MD5 cycles, again to reduce exposure. There may be no
* matching association and that's okay.
@@ -519,6 +496,27 @@ receive(
NTOHL_FP(&pkt->xmt, &p_xmt);
/*
+ * Update the MRU list and finger the cloggers. It can be a
+ * little expensive, so turn it off for production use.
+ */
+ restrict_mask = ntp_monitor(rbufp, restrict_mask);
+ if (restrict_mask & RES_LIMITED && retcode == AM_FXMIT) {
+ sys_limitrejected++;
+ if (!(restrict_mask & RES_KOD) || MODE_BROADCAST ==
+ hismode || MODE_SERVER == hismode)
+ return; /* rate exceeded */
+
+ if (hismode == MODE_CLIENT)
+ fast_xmit(rbufp, MODE_SERVER, skeyid,
+ restrict_mask);
+ else
+ fast_xmit(rbufp, MODE_ACTIVE, skeyid,
+ restrict_mask);
+ return; /* rate exceeded */
+ }
+ restrict_mask &= ~RES_KOD;
+
+ /*
* Authentication is conditioned by three switches:
*
* NOPEER (RES_NOPEER) do not mobilize an association unless
@@ -940,6 +938,10 @@ receive(
case AM_NEWPASS:
if (!AUTH(sys_authenticate | (restrict_mask &
(RES_NOPEER | RES_DONTTRUST)), is_authentic)) {
+ if (restrict_mask & RES_LIMITED) {
+ sys_limitrejected++;
+ return;
+ }
/*
* If authenticated but cannot mobilize an