keytab-backend - Extract keytabs from the KDC without changing the key

       Russ Allbery <eagle@eyrie.org>

       Copyright 2006-2008, 2010, 2013 The Board of Trustees of the Leland Stanford Junior University

       Permission  is  hereby  granted,  free  of  charge,  to  any person obtaining a copy of this software and
       associated documentation files (the "Software"), to deal in the Software without  restriction,  including
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       The  above  copyright  notice  and  this permission notice shall be included in all copies or substantial
       portions of the Software.

       THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  IMPLIED,  INCLUDING  BUT  NOT
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       SPDX-License-Identifier: MIT

keytab-backend retrieves a keytab for an existing principal from the KDC database without changing the
       current key.  It allows generation of a keytab for a service without rekeying that service.  It requires
       a kadmin.local patched to support the -norandkey option to ktadd.

       This script is intended to run under remctld.  On success, it prints the keytab to standard output, logs
       a success message to syslog (facility auth, priority info), and exits with status 0.  On failure, it
       prints out an error message, logs an error to syslog (facility auth, priority err), and exits with a non-
       zero status.

       The principal is checked for basic sanity (only accepting alphanumerics, "_", and "-" with an optional
       instance and then only alphanumerics, "_", "-", and "." in the realm) and then checked against a
       configuration file that lists regexes of principals that can be retrieved.  When deploying this software,
       limit as tightly as possible which principals can be downloaded in this fashion.  Generally only shared
       service principals used on multiple systems should be made available in this way.

       keytab-backend does not do any authorization checks.  Those should be done by remctld before it is
       called.

/etc/krb5kdc/allow-extract
           The  configuration file that controls which principals can have their keytabs retrieved.  Blank lines
           and lines starting with "#", as well as anything after "#" on a line, are ignored.  All  other  lines
           should  be  Perl  regular  expressions,  one  per  line,  that  match principals whose keytabs can be
           retrieved by keytab-backend.  Any principal that does not match  one  of  those  regular  expressions
           cannot be retrieved.

       /var/lib/keytabs
           The  temporary  directory  used  for creating keytabs.  keytab-backend will create the keytab in this
           directory, make sure that was successful, and then delete the temporary file after the  results  have
           been sent to standard output.

       keytab-backend - Extract keytabs from the KDC without changing the key

kadmin.local(8), remctld(8)

       This  program  is   part   of   the   wallet   system.    The   current   version   is   available   from
       <https://www.eyrie.org/~eagle/software/wallet/>.

1.5                                                2024-04-30                                  KEYTAB-BACKEND(8)

keytab-backend retrieve principal