[Sec 3042] Broadcast Interleave. HStenn.

bk: 57441e1aNmfyDNmP7RjTcs0p5QLpWQ

diff --git a/ChangeLog b/ChangeLog
index f61a4479808cbb2aad460ac9d99592b64bd577ca..88057044818858909c382d82e930274d7e223fc6 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+---
+
+* [Sec 3042] Broadcast Interleave.  HStenn.
+
 ---
 (4.2.8p7) 2016/04/26 Released by Harlan Stenn <stenn@ntp.org>
 

diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c
index 713a0c20dfa565e1ced2319cd628db8c16e79f93..8078cbe1cd36a07bb56b5468cd1bd67a358e29ba 100644 (file)
--- a/ntpd/ntp_proto.c
+++ b/ntpd/ntp_proto.c
@@ -568,7 +568,7 @@ receive(
        int     kissCode = NOKISS;      /* Kiss Code */
        int     has_mac;                /* length of MAC field */
        int     authlen;                /* offset of MAC field */
-       int     is_authentic = 0;       /* cryptosum ok */
+       int     is_authentic = AUTH_NONE;       /* cryptosum ok */
        int     crypto_nak_test;        /* result of crypto-NAK check */
        int     retcode = AM_NOMATCH;   /* match code */
        keyid_t skeyid = 0;             /* key IDs */
@@ -616,6 +616,8 @@ receive(
        hisleap = PKT_LEAP(pkt->li_vn_mode);
        hismode = (int)PKT_MODE(pkt->li_vn_mode);
        hisstratum = PKT_TO_STRATUM(pkt->stratum);
+       INSIST(0 != hisstratum);
+
        if (restrict_mask & RES_IGNORE) {
                sys_restricted++;
                return;                         /* ignore everything */
@@ -1512,7 +1514,7 @@ receive(
         */
        if (L_ISZERO(&p_xmt)) {
                peer->flash |= TEST3;                   /* unsynch */
-               if (0 == hisstratum) {                  /* KoD packet */
+               if (STRATUM_UNSPEC == hisstratum) {     /* KoD packet */
                        peer->bogusorg++;               /* for TEST2 or TEST3 */
                        msyslog(LOG_INFO,
                                "receive: Unexpected zero transmit timestamp in KoD from %s",
@@ -1531,17 +1533,22 @@ receive(
                return;
 
        /*
-        * If this is a broadcast mode packet, skip further checking. If
-        * an initial volley, bail out now and let the client do its
-        * stuff. If the origin timestamp is nonzero, this is an
-        * interleaved broadcast. so restart the protocol.
+        * If this is a broadcast mode packet, make sure hisstratum
+        * is appropriate.  Don't do anything else here - we wait to
+        * see if this is an interleave broadcast packet until after
+        * we've validated the MAC that SHOULD be provided.
+        *
+        * hisstratum should never be 0.
+        * If hisstratum is 15, then we'll advertise as UNSPEC but
+        * at least we'll be able to sync with the broadcast server.
         */
        } else if (hismode == MODE_BROADCAST) {
-               if (!L_ISZERO(&p_org) && !(peer->flags & FLAG_XB)) {
-                       peer->flags |= FLAG_XB;
-                       peer->aorg = p_xmt;
-                       peer->borg = rbufp->recv_time;
-                       report_event(PEVNT_XLEAVE, peer, NULL);
+               if (   0 == hisstratum
+                   || STRATUM_UNSPEC <= hisstratum) {
+                       /* Is this a ++sys_declined or ??? */
+                       msyslog(LOG_INFO,
+                               "receive: Unexpected stratum (%d) in broadcast from %s",
+                               hisstratum, ntoa(&peer->srcadr));
                        return;
                }
 
@@ -1558,7 +1565,7 @@ receive(
         * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp
         * that we have previously sent out.  Watch interleave mode.
         */
-       } else if (0 == hisstratum) {
+       } else if (STRATUM_UNSPEC == hisstratum) {
                DEBUG_INSIST(!L_ISZERO(&p_xmt));
                if (   L_ISZERO(&p_org)         /* We checked p_xmt above */
                    || L_ISZERO(&p_rec)) {
@@ -1617,6 +1624,7 @@ receive(
         */
        } else if (peer->flip == 0) {
                INSIST(0 != hisstratum);
+               INSIST(STRATUM_UNSPEC != hisstratum);
                if (0) {
                } else if (L_ISZERO(&p_org)) {
                        msyslog(LOG_INFO,
@@ -1722,8 +1730,49 @@ receive(
        }
 
        /*
-        * Update the state variables.
+        * For broadcast packets:
+        *
+        * HMS: This next line never made much sense to me, even
+        * when it was up higher:
+        *   If an initial volley, bail out now and let the
+        *   client do its stuff.
+        *
+        * If the packet has not failed authentication, then
+        * - if the origin timestamp is nonzero this is an
+        *   interleaved broadcast, so restart the protocol.
+        * - else, this is not an interleaved broadcast packet.
         */
+       if (hismode == MODE_BROADCAST) {
+               if (   is_authentic == AUTH_OK
+                   || is_authentic == AUTH_NONE) {
+                       if (!L_ISZERO(&p_org)) {
+                               if (!(peer->flags & FLAG_XB)) {
+                                       msyslog(LOG_INFO,
+                                               "receive: Broadcast server at %s is in interleave mode",
+                                               ntoa(&peer->srcadr));
+                                       peer->flags |= FLAG_XB;
+                                       peer->aorg = p_xmt;
+                                       peer->borg = rbufp->recv_time;
+                                       report_event(PEVNT_XLEAVE, peer, NULL);
+                                       return;
+                               }
+                       } else if (peer->flags & FLAG_XB) {
+                               msyslog(LOG_INFO,
+                                       "receive: Broadcast server at %s is no longer in interleave mode",
+                                       ntoa(&peer->srcadr));
+                               peer->flags &= ~FLAG_XB;
+                       }
+               } else {
+                       msyslog(LOG_INFO,
+                               "receive: Bad broadcast auth (%d) from %s",
+                               is_authentic, ntoa(&peer->srcadr));
+               }
+       }
+
+
+       /*
+       ** Update the state variables.
+       */
        if (peer->flip == 0) {
                if (hismode != MODE_BROADCAST)
                        peer->rec = p_xmt;
@@ -1766,6 +1815,12 @@ receive(
                return;         /* Drop any other kiss code packets */
        }
 
+
+       /*
+        * XXX
+        */
+
+
        /*
         * If:
         *      - this is a *cast (uni-, broad-, or m-) server packet