Date: Sun, 19 Aug 2001 02:20:01 -0700 (PDT) From: Kris Kennaway <kris@obsecurity.org> To: freebsd-bugs@FreeBSD.org Subject: Re: misc/29867: 4.3 timed master can't sync Red Hat Linux 6.0 box Message-ID: <200108190920.f7J9K1E43753@freefall.freebsd.org>
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The following reply was made to PR misc/29867; it has been noted by GNATS.
From: Kris Kennaway <kris@obsecurity.org>
To: Steve Whiteley <stevew@wrcad.com>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: misc/29867: 4.3 timed master can't sync Red Hat Linux 6.0 box
Date: Sun, 19 Aug 2001 02:18:52 -0700
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> The problem is that the sizeof(struct tsp) differs on the two systems.
> Made the following change in readmsg.c near line 215, which seems to have=
fixed the problem.
> ----------------------------------------------------------------------
> length =3D sizeof(from);
> if ((n =3D recvfrom(sock, (char *)&msgin, sizeof(struct tsp), 0,
> (struct sockaddr*)&from, &length)) < 0) {
> syslog(LOG_ERR, "recvfrom: %m");
> exit(1);
> }
> /* SRW */
> /* Here is a bug: the sizeof(struct tsp) is OS dependent, depending on the
> * length of the tsp_name field (MAXHOSTNAMELEN) which is, e.g., 256 for
> * FreeBSD 4.3 and 64 for RH Linux 6.0. Keep this as a sanity check,
> * but assume that the name field is 64 or larger
> */ =20
> if (n < (ssize_t)sizeof(struct tsp) - MAXHOSTNAMELEN + 64) {
> /*
> if (n < (ssize_t)sizeof(struct tsp)) {
> */
> syslog(LOG_NOTICE,
> "short packet (%u/%u bytes) from %s",
> n, sizeof(struct tsp),
> inet_ntoa(from.sin_addr));
> continue; =20
> }
I think this is a more complete fix. According to
http://sunsite.berkeley.edu/Dienst/UI/2.0/Describe/ncstrl.ucb/CSD-85-250
the original 4.3BSD code had sizeof(tsp.tsp_name) =3D=3D 32, so that's
probably a safe minimum packet size to use. Can you please test?
Kris
Index: timed/readmsg.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /mnt/ncvs/src/usr.sbin/timed/timed/readmsg.c,v
retrieving revision 1.7
diff -u -r1.7 readmsg.c
--- timed/readmsg.c 2001/01/01 18:43:21 1.7
+++ timed/readmsg.c 2001/08/19 09:14:07
@@ -212,10 +212,15 @@
syslog(LOG_ERR, "recvfrom: %m");
exit(1);
}
- if (n < (ssize_t)sizeof(struct tsp)) {
+ /*
+ * The 4.3BSD protocol spec had a 32-byte tsp_name field, and
+ * this is still OS-dependent. Demand that the packet is at
+ * least long enough to hold a 4.3BSD packet.
+ */
+ if (n < (ssize_t)(sizeof(struct tsp) - MAXHOSTNAMELEN + 32)) {
syslog(LOG_NOTICE,
"short packet (%u/%u bytes) from %s",
- n, sizeof(struct tsp),
+ n, sizeof(struct tsp) - MAXHOSTNAMELEN + 32,
inet_ntoa(from.sin_addr));
continue;
}
Index: timedc/cmds.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /mnt/ncvs/src/usr.sbin/timed/timedc/cmds.c,v
retrieving revision 1.7
diff -u -r1.7 cmds.c
--- timedc/cmds.c 2001/05/09 08:37:18 1.7
+++ timedc/cmds.c 2001/08/19 09:17:16
@@ -332,10 +332,15 @@
warn("recvfrom");
continue;
}
- if (cc < sizeof(struct tsp)) {
+ /*
+ * The 4.3BSD protocol spec had a 32-byte tsp_name field, and
+ * this is still OS-dependent. Demand that the packet is at
+ * least long enough to hold a 4.3BSD packet.
+ */
+ if (cc < (sizeof(struct tsp) - MAXHOSTNAMELEN + 32)) {
fprintf(stderr,=20
"short packet (%u/%u bytes) from %s\n",
- cc, sizeof(struct tsp),
+ cc, sizeof(struct tsp) - MAXHOSTNAMELEN + 32,
inet_ntoa(from.sin_addr));
continue;
}
@@ -484,9 +489,15 @@
warn("recvfrom");
return;
}
- if (cc < sizeof(struct tsp)) {
- fprintf(stderr, "short pack (%u/%u bytes) from %s\n",
- cc, sizeof(struct tsp), inet_ntoa(from.sin_addr));
+ /*
+ * The 4.3BSD protocol spec had a 32-byte tsp_name field, and
+ * this is still OS-dependent. Demand that the packet is at
+ * least long enough to hold a 4.3BSD packet.
+ */
+ if (cc < (sizeof(struct tsp) - MAXHOSTNAMELEN + 32)) {
+ fprintf(stderr, "short packet (%u/%u bytes) from %s\n",
+ cc, sizeof(struct tsp) - MAXHOSTNAMELEN + 32,
+ inet_ntoa(from.sin_addr));
return;
}
bytehostorder(&msg);
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