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Unix/Linux 网络时间协议版本3 Network Time Protocol Version 3 (NTP) distribution for Unix systems

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          17 Feb 1998 10:51 EST
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	Tue, 17 Feb 1998 16:51:13 +0100
Date: Tue, 17 Feb 1998 16:51:13 +0100
From: Juha Sarlin <[e-mail]>
Message-Id: <[e-mail]>
To: [e-mail]
Cc: [e-mail]
Subject: Multicast client fix for xntp3-5.92
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Content-Type: text/plain; charset=US-ASCII

When a multicast server becomes unreachable its peer structure is
freed in transmit(), but later that function queues another timer
event on the removed peer. Next time unpeer() is called with this
already freed peer structure, it dies on a NULL dereference.

*** xntpd/ntp_proto.c.orig	Fri Oct 10 03:36:48 1997
--- xntpd/ntp_proto.c	Tue Feb 17 01:12:48 1998
***************
*** 257,264 ****
  					peer_clear(peer);
  					peer->timereachable = current_time;
  				}
! 			} else if (peer->flags & FLAG_MCAST2)
  				unpeer(peer);
  
  			/*
  			 * While we have a chance, if our system peer is
--- 257,266 ----
  					peer_clear(peer);
  					peer->timereachable = current_time;
  				}
! 			} else if (peer->flags & FLAG_MCAST2) {
  				unpeer(peer);
+ 				return;
+ 			}
  
  			/*
  			 * While we have a chance, if our system peer is

*** xntpd/ntp_peer.c.orig	Tue Jul 15 07:32:45 1997
--- xntpd/ntp_peer.c	Tue Feb 17 01:12:48 1998
***************
*** 324,330 ****
  		if (peer == 0) {
  			peer_hash_count[hash]++;
  			msyslog(LOG_ERR, "peer struct for %s not in table!",
! 			    ntoa(&peer->srcadr));
  		} else {
  			peer->next = peer_to_remove->next;
  		}
--- 324,330 ----
  		if (peer == 0) {
  			peer_hash_count[hash]++;
  			msyslog(LOG_ERR, "peer struct for %s not in table!",
! 			    ntoa(&peer_to_remove->srcadr));
  		} else {
  			peer->next = peer_to_remove->next;
  		}
***************
*** 348,354 ****
  			assoc_hash_count[hash]++;
  			msyslog(LOG_ERR,
  			    "peer struct for %s not in association table!",
! 			    ntoa(&peer->srcadr));
  		} else {
  			peer->ass_next = peer_to_remove->ass_next;
  		}
--- 348,354 ----
  			assoc_hash_count[hash]++;
  			msyslog(LOG_ERR,
  			    "peer struct for %s not in association table!",
! 			    ntoa(&peer_to_remove->srcadr));
  		} else {
  			peer->ass_next = peer_to_remove->ass_next;
  		}