Bug 163876 - kshd hangs on incoming krdist which utilizes the "special" option
kshd hangs on incoming krdist which utilizes the "special" option
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: krb5 (Show other bugs)
i386 Linux
medium Severity high
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Assigned To: Nalin Dahyabhai
Brian Brock
Depends On:
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Reported: 2005-07-21 15:02 EDT by Geoff Silver
Modified: 2007-11-30 17:07 EST (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2007-10-19 14:57:46 EDT
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Description Geoff Silver 2005-07-21 15:02:14 EDT
From Bugzilla Helper:
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Description of problem:
The krb5-1.2.7-krsh-deadlock2.patch introducted in krb5-1.2.7-39 on Red Hat EL3.0 creates a bug which potentially causes an incoming encrypted rdist to hang and timeout.  This bug also exists in some or all EL4.0 krb5-workstation packages; however, I do not have the resources available to track down which specific versions.

Version-Release number of selected component (if applicable):
krb5-1.2.7-39 and newer

How reproducible:

Steps to Reproduce:
0. Turn off any firewall rules on both hosts, as rdist requires a random high return TCP port, but isn't stateful with respect to kshd/kshell.

1. On source system, create an rdist file which containas a "special" line.  Here is a sample "distfile":

FILES = (/etc/syslog.conf)
${FILES} -> ${HOSTS}
        install /tmp/. ;
        special "echo 'hello world' >> /tnp/syslog.conf";

2. On the target system (targethost.redhat.com in this case), enable 'kshell' in xinetd.d.

3. On the source system, use a kerberized rdist client, such as the MIT krdist.  Run 'krdist -f distfile'.  The krdist will hang and eventually timeout.  If you comment out the "special" line, it will work.  Note that it will always work on repeated attempts once /tmp/syslog.conf gets written (as krdist won't send a file if it's unchanged), so make sure you delete it on the target system if it appears.

Actual Results:  krdist hangs.  On the target system, a temporary rdist file (/tmp/rdistXXXXX) appears with the data that should be written out to the final file (/tmp/syslog.conf), isn't.

Expected Results:  krdist should complete almost immediately.

Additional info:

This problem started with krb5-workstation-1.2.7-39.  There is only one patch in -39, so there is *something* wrong with that patch.
Comment 1 Geoff Silver 2005-07-21 15:03:21 EDT
sorry, that special line should actually >> /tmp/syslog.conf
Comment 3 RHEL Product and Program Management 2007-10-19 14:57:46 EDT
This bug is filed against RHEL 3, which is in maintenance phase.
During the maintenance phase, only security errata and select mission
critical bug fixes will be released for enterprise products. Since
this bug does not meet that criteria, it is now being closed.
For more information of the RHEL errata support policy, please visit:
If you feel this bug is indeed mission critical, please contact your
support representative. You may be asked to provide detailed
information on how this bug is affecting you.

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