Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!SCCGATE.SCC.COM!oconnor
From: oconnor@SCCGATE.SCC.COM (Michael J. O'Connor)
Newsgroups: comp.protocols.tcp-ip
Subject: IP options crash our Sun gateway
Message-ID: <8803151852.AA12900@sccgate.scc.com>
Date: 15 Mar 88 18:52:37 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 23

When our stock SMI DDN gateway attempted to forward IP-grams containing RR or
LSRR options, it would crash.  Our box is a 3/260 running SOS 3.5 and acts as
a gateway between our local ethernet-based network and the ARPANET.  We have
only been able to test this behavior on outgoing packets, but if we are correct
in our diagnosis, the problem should occur when the box attempts to forward any
IP-option bearing packets in either direction.

According to the engineer assigned to our service request, Sun has assigned the
problem bug number 1008944 but will not supply a fix for 3.n SOS.  He stated
that the problem should be fixed in 4.0 SOS which will be distributed later in
1988.

Based on a report from Allison Mankin of MITRE, that the crashing is caused by
a previously reported typo in ip_stripoption(), I have patched our binary in an
attempt to reverse the effects of the typo.  The patch has been working now for
a little over 2 weeks.  Working in the sense that our machine no longer crashes
when forwarding IPgrams which contain options.  I have yet to verify what is
going out the other interface.

If anyone else is affected by this, and the legal boys allow it, I am willing
to supply the binary patch.  It only consists of modifying a register value
in 2 consecutive instructions.

			Mike