[2712] in Kerberos-V5-bugs
Re: krb5-appl/406: telnetd hoses the host at fork()
daemon@ATHENA.MIT.EDU (Theodore Y. Ts'o)
Mon Mar 31 19:24:00 1997
Date: Mon, 31 Mar 1997 19:21:41 -0500
From: "Theodore Y. Ts'o" <tytso@MIT.EDU>
To: krb5-bugs@MIT.EDU, mdo1@dbatest.cit.cornell.edu
Cc: krb5-unassigned@RT-11.MIT.EDU, gnats-admin@RT-11.MIT.EDU,
krb5-prs@RT-11.MIT.EDU
In-Reply-To: Michael D Oltz's message of Fri, 28 Mar 1997 15:51:02 -0500,
<199703282051.PAA10704@rt-11.MIT.EDU>
Date: Fri, 28 Mar 1997 15:49:42 -0500
From: mdo1@dbatest.cit.cornell.edu (Michael D Oltz)
tried to use the 16-bit NCSA Telnet for Windows bundled
with the K5 1.0 release to connect to my K5 server host
running the K5 telnetd (on a high port number as an
alternate). daemon gets through authentication okay,
then it calls startslave. when it gets to the fork
call, the daemon causes a hard crash (cold boot required).
i haven't stepped into the kernel yet, but it crashes
fast enough that gdb doesn't report the creation of a
new thread. it could be that the child starts, but dies
before the parent gets to return from the fork()
p.s. i can gssftp from aforementioned
host to itself without trouble. but self-telnet dies.
connecting with any vanilla telnet client causes the
same problem. any advice? anybody else had this problem?
This is a known problem with AIX 4.1; our pty handling is somehow
causing AIX 4.x to lock up and crash. While this clearly means there's
a bug in our pty library, it's also a major bug in AIX that a user
program can cause the kernel to panic.
We don't have any AIX machines within easy access of our development
team, so we're going to be relying on others (who have the misfortune of
having to use AIX :-) to try to fix this problem. For whatever it's
worth, our pty code works just fine under AIX 3.x; not only do the
kernels not panic, but telnetd and rlogind actually work! Clearly, IBM
changed some very significant things in its pty handling code between
AIX 3 and AIX 4.
If anyone has any suggestions, or better yet patches, we would be
greatly appreciative of them.
- Ted
