Copyright © 1985-2007 by the Massachusetts Institute of Technology.
Export of software employing encryption from the United States of America may require a specific license from the United States Government. It is the responsibility of any person or organization contemplating export to obtain such a license before exporting.
WITHIN THAT CONSTRAINT, permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of M.I.T. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. Furthermore if you modify this software you must label your software as modified software and not distribute it in such a fashion that it might be confused with the original MIT software. M.I.T. makes no representations about the suitability of this software for any purpose. It is provided “as is” without express or implied warranty.
Individual source code files are copyright MIT, Cygnus Support, Novell, OpenVision Technologies, Oracle, Red Hat, Sun Microsystems, FundsXpress, and others.
Project Athena, Athena, Athena MUSE, Discuss, Hesiod, Kerberos, Moira, and Zephyr are trademarks of the Massachusetts Institute of Technology (MIT). No commercial use of these trademarks may be made without prior written permission of MIT.
“Commercial use” means use of a name in a product or other for-profit manner. It does NOT prevent a commercial firm from referring to the MIT trademarks in order to convey information (although in doing so, recognition of their trademark status should be given).
The following copyright and permission notice applies to the
OpenVision Kerberos Administration system located in
kadmin/create, kadmin/dbutil, kadmin/passwd,
kadmin/server, lib/kadm5, and portions of
lib/rpc:
Copyright, OpenVision Technologies, Inc., 1996, All Rights ReservedWARNING: Retrieving the OpenVision Kerberos Administration system source code, as described below, indicates your acceptance of the following terms. If you do not agree to the following terms, do not retrieve the OpenVision Kerberos administration system.
You may freely use and distribute the Source Code and Object Code compiled from it, with or without modification, but this Source Code is provided to you “AS IS” EXCLUSIVE OF ANY WARRANTY, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, OR ANY OTHER WARRANTY, WHETHER EXPRESS OR IMPLIED. IN NO EVENT WILL OPENVISION HAVE ANY LIABILITY FOR ANY LOST PROFITS, LOSS OF DATA OR COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, INCLUDING, WITHOUT LIMITATION, THOSE RESULTING FROM THE USE OF THE SOURCE CODE, OR THE FAILURE OF THE SOURCE CODE TO PERFORM, OR FOR ANY OTHER REASON.
OpenVision retains all copyrights in the donated Source Code. OpenVision also retains copyright to derivative works of the Source Code, whether created by OpenVision or by a third party. The OpenVision copyright notice must be preserved if derivative works are made based on the donated Source Code.
OpenVision Technologies, Inc. has donated this Kerberos Administration system to MIT for inclusion in the standard Kerberos 5 distribution. This donation underscores our commitment to continuing Kerberos technology development and our gratitude for the valuable work which has been performed by MIT and the Kerberos community.
Portions contributed by Matt Crawford <crawdad@fnal.gov> were work
performed at Fermi National Accelerator Laboratory, which is operated
by Universities Research Association, Inc., under contract
DE-AC02-76CHO3000 with the U.S. Department of Energy.
Portions of src/lib/crypto have the following copyright:
Copyright © 1998 by the FundsXpress, INC.All rights reserved.
Export of this software from the United States of America may require a specific license from the United States Government. It is the responsibility of any person or organization contemplating export to obtain such a license before exporting.
WITHIN THAT CONSTRAINT, permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of FundsXpress. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. FundsXpress makes no representations about the suitability of this software for any purpose. It is provided “as is” without express or implied warranty.
THIS SOFTWARE IS PROVIDED “AS IS” AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
The implementation of the Yarrow pseudo-random number generator
in src/lib/crypto/yarrow has the following copyright:
Copyright 2000 by Zero-Knowledge Systems, Inc.Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Zero-Knowledge Systems, Inc. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. Zero-Knowledge Systems, Inc. makes no representations about the suitability of this software for any purpose. It is provided “as is” without express or implied warranty.
ZERO-KNOWLEDGE SYSTEMS, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL ZERO-KNOWLEDGE SYSTEMS, INC. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTUOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
The implementation of the AES encryption algorithm in
src/lib/crypto/aes has the following copyright:
Copyright © 2001, Dr Brian Gladman<brg@gladman.uk.net>, Worcester, UK.
All rights reserved.LICENSE TERMS
The free distribution and use of this software in both source and binary form is allowed (with or without changes) provided that:
- distributions of this source code include the above copyright notice, this list of conditions and the following disclaimer;
- distributions in binary form include the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other associated materials;
- the copyright holder's name is not used to endorse products built using this software without specific written permission.
DISCLAIMER
This software is provided 'as is' with no explcit or implied warranties in respect of any properties, including, but not limited to, correctness and fitness for purpose.
Portions contributed by Red Hat, including the pre-authentication plug-in framework, contain the following copyright:
Copyright © 2006 Red Hat, Inc.
Portions copyright © 2006 Massachusetts Institute of Technology
All Rights Reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- Neither the name of Red Hat, Inc., nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The implementations of GSSAPI mechglue in GSSAPI-SPNEGO in
src/lib/gssapi, including the following files:
lib/gssapi/generic/gssapi_err_generic.et
lib/gssapi/mechglue/g_accept_sec_context.c
lib/gssapi/mechglue/g_acquire_cred.c
lib/gssapi/mechglue/g_canon_name.c
lib/gssapi/mechglue/g_compare_name.c
lib/gssapi/mechglue/g_context_time.c
lib/gssapi/mechglue/g_delete_sec_context.c
lib/gssapi/mechglue/g_dsp_name.c
lib/gssapi/mechglue/g_dsp_status.c
lib/gssapi/mechglue/g_dup_name.c
lib/gssapi/mechglue/g_exp_sec_context.c
lib/gssapi/mechglue/g_export_name.c
lib/gssapi/mechglue/g_glue.c
lib/gssapi/mechglue/g_imp_name.c
lib/gssapi/mechglue/g_imp_sec_context.c
lib/gssapi/mechglue/g_init_sec_context.c
lib/gssapi/mechglue/g_initialize.c
lib/gssapi/mechglue/g_inquire_context.c
lib/gssapi/mechglue/g_inquire_cred.c
lib/gssapi/mechglue/g_inquire_names.c
lib/gssapi/mechglue/g_process_context.c
lib/gssapi/mechglue/g_rel_buffer.c
lib/gssapi/mechglue/g_rel_cred.c
lib/gssapi/mechglue/g_rel_name.c
lib/gssapi/mechglue/g_rel_oid_set.c
lib/gssapi/mechglue/g_seal.c
lib/gssapi/mechglue/g_sign.c
lib/gssapi/mechglue/g_store_cred.c
lib/gssapi/mechglue/g_unseal.c
lib/gssapi/mechglue/g_userok.c
lib/gssapi/mechglue/g_utils.c
lib/gssapi/mechglue/g_verify.c
lib/gssapi/mechglue/gssd_pname_to_uid.c
lib/gssapi/mechglue/mglueP.h
lib/gssapi/mechglue/oid_ops.c
lib/gssapi/spnego/gssapiP_spnego.h
lib/gssapi/spnego/spnego_mech.c
are subject to the following license:
Copyright © 2004 Sun Microsystems, Inc.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 without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
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 LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Kerberos V5 includes documentation and software developed at the University of California at Berkeley, which includes this copyright notice:
Copyright © 1983 Regents of the University of California.
All rights reserved.Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Portions contributed by Novell, Inc., including the LDAP database backend, are subject to the following license:
Copyright (c) 2004-2005, Novell, Inc. All rights reserved.Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- The copyright holder's name is not used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Portions funded by Sandia National Laboratory and developed by the University of Michigan's Center for Information Technology Integration, including the PKINIT implementation, are subject to the following license:
COPYRIGHT © 2006-2007
THE REGENTS OF THE UNIVERSITY OF MICHIGAN
ALL RIGHTS RESERVEDPermission is granted to use, copy, create derivative works and redistribute this software and such derivative works for any purpose, so long as the name of The University of Michigan is not used in any advertising or publicity pertaining to the use of distribution of this software without specific, written prior authorization. If the above copyright notice or any other identification of the University of Michigan is included in any copy of any portion of this software, then the disclaimer below must also be included.
THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
The pkcs11.h file included in the PKINIT code has the following license:
Copyright 2006 g10 Code GmbH Copyright 2006 Andreas Jellinghaus
This file is free software; as a special exception the author gives unlimited permission to copy and/or distribute it, with or without modifications, as long as this notice is preserved.
This file is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY, to the extent permitted by law; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notices and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions.
Since Kerberos negotiates authenticated, and optionally encrypted, communications between two points anywhere on the internet, it provides a layer of security that is not dependent on which side of a firewall either client is on. Since studies have shown that half of the computer security breaches in industry happen from inside firewalls, Kerberos V5 from MIT will play a vital role in the security of your network.
This document is one piece of the document set for Kerberos V5. The documents, and their intended audiences, are:
The next chapter describes how Kerberos works.
Chapter three describes administration of the principals in the Kerberos database.
Chapter four describes how you can use DNS in configuring your Kerberos realm.
Chapter five describes administrative programs for manipulating the Kerberos database as a whole.
Chapter six describes OpenLDAP Configuration steps.
Chapter seven describes issues to consider when adding an application server to the database.
Chapter eight describes our problem reporting system.
The appendices include the list of Kerberos error messages, and a
complete list of the time zones understood by kadmin.
This section provides a simplified description of a general user's
interaction with the Kerberos system. This interaction happens
transparently—users don't need to know and probably don't care about
what's going on—but Kerberos administrators might find a schematic
description of the process useful. This description glosses over a lot
of details; for more information, see Kerberos: An Authentication
Service for Open Network Systems, a paper presented at Winter USENIX
1988, in Dallas, Texas. This paper can be retreived by FTP from
athena-dist.mit.edu, in the location:
/pub/ATHENA/kerberos/doc/usenix.PS.
In an environment that provides network services, you use client programs to request services from server programs that are somewhere on the network. Suppose you have logged in to a workstation and you want to rlogin to a typical UNIX host. You use the local rlogin client program to contact the remote machine's rlogind daemon.
Under Kerberos, the klogind daemon allows you to login to a remote machine if you can provide klogind a Kerberos ticket which proves your identity. In addition to the ticket, you must also have possession of the corresponding ticket session key. The combination of a ticket and the ticket's session key is known as a credential.
Typically, a client program automatically obtains credentials identifying the person using the client program. The credentials are obtained from a Kerberos server that resides somewhere on the network. A Kerberos server maintains a database of user, server, and password information.
Kerberos will give you credentials only if you have an entry in the Kerberos server's Kerberos database. Your database entry includes your Kerberos principal (an identifying string, which is often just your username), and your Kerberos password. Every Kerberos user must have an entry in this database.
Each administrative domain will have its own Kerberos database, which contains information about the users and services for that particular site or administrative domain. This administrative domain is the Kerberos realm.
Each Kerberos realm will have at least one Kerberos server, where the master Kerberos database for that site or administrative domain is stored. A Kerberos realm may also have one or more slave servers, which have read-only copies of the Kerberos database that are periodically propagated from the master server. For more details on how this is done, see the “Set Up the Slave KDCs for Database Propagation” and “Propagate the Database to Each Slave KDC” sections of the Kerberos V5 Installation Guide.
The kinit command prompts for your password. If you enter it successfully, you will obtain a ticket-granting ticket and a ticket session key which gives you the right to use the ticket. This combination of the ticket and its associated key is known as your credentials. As illustrated below, client programs use your ticket-granting ticket credentials in order to obtain client-specific credentials as needed.
Your credentials are stored in a credentials cache, which is often
just a file in /tmp. The credentials cache is also called the
ticket file, especially in Kerberos V4 documentation. Note,
however, that a credentials cache does not have to be stored in a file.
The master database also contains entries for all network services that require Kerberos authentication. Suppose that your site has a machine, laughter.mit.edu, that requires Kerberos authentication from anyone who wants to rlogin to it. The host's Kerberos realm is ATHENA.MIT.EDU.
This service must be registered in the Kerberos database, using the proper service name, which in this case is the principal:
host/laughter.mit.edu@ATHENA.MIT.EDU
The / character separates the Kerberos primary (in this case, host) from the instance (in this case, laughter.mit.edu); the @ character separates the realm name (in this case, ATHENA.MIT.EDU) from the rest of the principal. The primary, host, denotes the name or type of the service that is being offered: generic host-level access to the machine. The instance, laughter.mit.edu, names the specific machine that is offering this service. There will generally be many different machines, each offering one particular type of service, and the instance serves to give each one of these servers a different Kerberos principal.
For each service, there must also be a service key known only by Kerberos and the service. On the Kerberos server, the service key is stored in the Kerberos database.
On the server host, these service keys are stored in key tables,
which are files known as keytabs.1 For example, the service keys used by
services that run as root are usually stored in the keytab file
/etc/krb5.keytab. N.B.: This service key is the equivalent
of the service's password, and must be kept secure. Data which is meant
to be read only by the service is encrypted using this key.
Suppose that you walk up to a host intending to login to it, and then rlogin to the machine laughter. Here's what happens:
host% rlogin laughter
klogind will let you
login.
Following are definitions of some of the Kerberos terminology.
The typical format of a typical Kerberos principal is
primary/instance@REALM.
telnet and
rsh), “ftp” (FTP), “krbtgt” (authentication;
cf. ticket-granting ticket), and “pop” (email).
Any tag in the configuration files which requires a list of encryption types can be set to some combination of the following strings.
des-cbc-crcdes-cbc-md4des-cbc-md5des3-cbc-sha1des3-hmac-sha1des3-cbc-sha1-kddes-hmac-sha1aes256-cts-hmac-sha1-96aes256-ctsaes128-cts-hmac-sha1-96aes128-ctsarcfour-hmacrc4-hmacarcfour-hmac-md5arcfour-hmac-exprc4-hmac-exparcfour-hmac-md5-expWhile aes128-cts and aes256-cts are supported for all Kerberos operations, they are not supported by older versions of our GSSAPI implementation (krb5-1.3.1 and earlier).
By default, AES is enabled in this release. Sites wishing to use AES encryption types on their KDCs need to be careful not to give GSSAPI services AES keys if the servers have not been updated. If older GSSAPI services are given AES keys, then services may fail when clients supporting AES for GSSAPI are used. Sites may wish to use AES for user keys and for the ticket granting ticket key, although doing so requires specifying what encryption types are used as each principal is created.
If all GSSAPI-based services have been updated before or with the KDC, this is not an issue.
Your Kerberos key is derived from your password. To ensure that people who happen to pick the same password do not have the same key, Kerberos 5 incorporates more information into the key using something called a salt. The supported values for salts are as follows.
normalv4norealmonlyrealmafs3specialThe krb5.conf file contains Kerberos configuration information,
including the locations of KDCs and admin servers for the Kerberos
realms of interest, defaults for the current realm and for Kerberos
applications, and mappings of hostnames onto Kerberos realms. Normally,
you should install your krb5.conf file in the directory
/etc. You can override the default location by setting the
environment variable KRB5_CONFIG.
The krb5.conf file is set up in the style of a Windows INI file.
Sections are headed by the section name, in square brackets. Each
section may contain zero or more relations, of the form:
foo = bar
or
fubar = {
foo = bar
baz = quux
}
Placing a `*' at the end of a line indicates that this is the final value for the tag. This means that neither the remainder of this configuration file nor any other configuration file will be checked for any other values for this tag.
For example, if you have the following lines:
foo = bar*
foo = baz
then the second value of foo (baz) would never be read.
The krb5.conf file may contain any or all of the following
sections:
The libdefaults section may contain any of the following
relations:
Enabling this option does open up a type of denial-of-service attack, if someone spoofs the DNS records and redirects you to another server. However, it's no worse than a denial of service, because that fake KDC will be unable to decode anything you send it (besides the initial ticket request, which has no encrypted data), and anything the fake KDC sends will not be trusted without verification using some secret that it won't know.
If this option is not specified but dns_fallback is, that value will be used instead. If neither option is specified, the behavior depends on configure-time options; if none were given, the default is to enable this option. If the DNS support is not compiled in, this entry has no effect.
Enabling this option may permit a redirection attack, where spoofed DNS replies persuade a client to authenticate to the wrong realm, when talking to the wrong host (either by spoofing yet more DNS records or by intercepting the net traffic). Depending on how the client software manages hostnames, however, it could already be vulnerable to such attacks. We are looking at possible ways to minimize or eliminate this exposure. For now, we encourage more adventurous sites to try using Secure DNS.
If this option is not specified but dns_fallback is, that value will be used instead. If neither option is specified, the behavior depends on configure-time options; if none were given, the default is to disable this option. If the DNS support is not compiled in, this entry has no effect.
udp_preference_list.
If the message is smaller than udp_preference_list, then UDP
will be tried before TCP. Regardless of the size, both protocols will
be tried if the first attempt fails.
Each tag in the [appdefaults] section names a Kerberos V5 application or an option that is used by some Kerberos V5 application[s]. The value of the tag defines the default behaviors for that application.
For example:
[appdefaults]
telnet = {
ATHENA.MIT.EDU = {
option1 = false
}
}
telnet = {
option1 = true
option2 = true
}
ATHENA.MIT.EDU = {
option2 = false
}
option2 = true
The above four ways of specifying the value of an option are shown in order of decreasing precedence. In this example, if telnet is running in the realm EXAMPLE.COM, it should, by default, have option1 and option2 set to true. However, a telnet program in the realm ATHENA.MIT.EDU should have option1 set to false and option2 set to true. Any other programs in ATHENA.MIT.EDU should have option2 set to false by default. Any programs running in other realms should have option2 set to true.
The list of specifiable options for each application may be found in that application's man pages. The application defaults specified here are overridden by those specified in the [realms] section.
A special application name (afs_krb5) is used by the krb524 service to
know whether new format AFS tokens based on Kerberos 5 can be used
rather than the older format which used a converted Kerberos 4 ticket.
The new format allows for cross-realm authentication without
introducing a security hole. It is used by default. Older AFS
servers (before OpenAFS 1.2.8) will not support the new format. If
servers in your cell do not support the new format, you will need to
add an afs_krb5 relation to the appdefaults section.
The following config file shows how to disable new format AFS tickets
for the afs.example.com cell in the EXAMPLE.COM realm.
[appdefaults]
afs_krb5 = {
EXAMPLE.COM = {
afs/afs.example.com = false
}
}
Each tag in the [login] section of the file is an option for login.krb5. This section may contain any of the following relations:
Each tag in the [realms] section of the file is the name of a Kerberos realm. The value of the tag is a subsection with relations that define the properties of that particular realm. For each realm, the following tags may be specified in the realm's subsection:
The format for exp is
[n:$d..string](regexp)s/pattern/replacement/g.
The integer n indicates how many components the target principal
should have. If this matches, then a string will be formed by putting
together the components of the principal in the order indicated by each
integer d, and the arbitrary string string (i.e. if the
principal was johndoe/admin then [2:$2$1foo] would result in
the string "adminjohndoefoo". If this string matches
regexp, then the s//[g] substitution command will be run over the
string. The optional g will cause the substitution to be global over
the string, instead of replacing only the first match in the string.
For example:
[realms]
ATHENA.MIT.EDU = {
auth_to_local = {
RULE:[2:$1](johndoe)s/^.*$/guest/
RULE:[2:$1;$2](^.*;admin$)s/;admin$//
RULE:[2:$2](^.*;root)s/^.*$/root/
DEFAULT
}
}
would result in any principal without root or admin as
the second component to be translated with the default rule. A
principal with a second component of admin will become its first
component. root will be used as the local name for any
principal with a second component of root. The exception to
these two rules are any principals johndoe/*, which will
always get the local name guest.
The [domain_realm] section provides a translation from a domain name or hostname to a Kerberos realm name. The tag name can be a host name, or a domain name, where domain names are indicated by a prefix of a period (.). The value of the relation is the Kerberos realm name for that particular host or domain. Host names and domain names should be in lower case.
If no translation entry applies, the host's realm is considered to be the hostname's domain portion converted to upper case. For example, the following [domain_realm] section:
[domain_realm]
.mit.edu = ATHENA.MIT.EDU
mit.edu = ATHENA.MIT.EDU
crash.mit.edu = TEST.ATHENA.MIT.EDU
example.com = EXAMPLE.COM
maps crash.mit.edu into the TEST.ATHENA.MIT.EDU realm. All other hosts in the mit.edu domain will map by default to the ATHENA.MIT.EDU realm, and all hosts in the example.com domain will map by default into the EXAMPLE.COM realm. Note the entries for the hosts mit.edu and example.com. Without these entries, these hosts would be mapped into the Kerberos realms EDU and ORG, respectively.
The [logging] section indicates how a particular entity is to perform its logging. The relations in this section assign one or more values to the entity name. Currently, the following entities are used:
Values are of the following forms:
The severity argument specifies the default severity of system log
messages. This may be any of the following severities supported by the
syslog(3) call, minus the LOG_ prefix: LOG_EMERG, LOG_ALERT,
LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, and LOG_DEBUG.
For example, a value of CRIT would specify LOG_CRIT severity.
The facility argument specifies the facility under which the messages are logged. This may be any of the following facilities supported by the syslog(3) call minus the LOG_ prefix: LOG_KERN, LOG_USER, LOG_MAIL, LOG_DAEMON, LOG_AUTH, LOG_LPR, LOG_NEWS, LOG_UUCP, LOG_CRON, and LOG_LOCAL0 through LOG_LOCAL7.
If no severity is specified, the default is ERR. If no facility is specified, the default is AUTH.
In the following example, the logging messages from the KDC will go to the console and to the system log under the facility LOG_DAEMON with default severity of LOG_INFO; and the logging messages from the administrative server will be appended to the file /var/adm/kadmin.log and sent to the device /dev/tty04.
[logging]
kdc = CONSOLE
kdc = SYSLOG:INFO:DAEMON
admin_server = FILE:/var/adm/kadmin.log
admin_server = DEVICE=/dev/tty04
In order to perform direct (non-hierarchical) cross-realm authentication, a database is needed to construct the authentication paths between the realms. This section defines that database.
A client will use this section to find the authentication path between its realm and the realm of the server. The server will use this section to verify the authentication path used by the client, by checking the transited field of the received ticket.
There is a tag for each participating realm, and each tag has subtags for each of the realms. The value of the subtags is an intermediate realm which may participate in the cross-realm authentication. The subtags may be repeated if there is more then one intermediate realm. A value of "." means that the two realms share keys directly, and no intermediate realms should be allowed to participate.
There are n**2 possible entries in this table, but only those entries which will be needed on the client or the server need to be present. The client needs a tag for its local realm, with subtags for all the realms of servers it will need to authenticate with. A server needs a tag for each realm of the clients it will serve.
For example, ANL.GOV, PNL.GOV, and NERSC.GOV all wish to use the ES.NET realm as an intermediate realm. ANL has a sub realm of TEST.ANL.GOV which will authenticate with NERSC.GOV but not PNL.GOV. The [capaths] section for ANL.GOV systems would look like this:
[capaths]
ANL.GOV = {
TEST.ANL.GOV = .
PNL.GOV = ES.NET
NERSC.GOV = ES.NET
ES.NET = .
}
TEST.ANL.GOV = {
ANL.GOV = .
}
PNL.GOV = {
ANL.GOV = ES.NET
}
NERSC.GOV = {
ANL.GOV = ES.NET
}
ES.NET = {
ANL.GOV = .
}
The [capaths] section of the configuration file used on NERSC.GOV systems would look like this:
[capaths]
NERSC.GOV = {
ANL.GOV = ES.NET
TEST.ANL.GOV = ES.NET
TEST.ANL.GOV = ANL.GOV
PNL.GOV = ES.NET
ES.NET = .
}
ANL.GOV = {
NERSC.GOV = ES.NET
}
PNL.GOV = {
NERSC.GOV = ES.NET
}
ES.NET = {
NERSC.GOV = .
}
TEST.ANL.GOV = {
NERSC.GOV = ANL.GOV
NERSC.GOV = ES.NET
}
In the above examples, the ordering is not important, except when the same subtag name is used more then once. The client will use this to determine the path. (It is not important to the server, since the transited field is not sorted.)
This feature is not currently supported by DCE. DCE security servers can be used with Kerberized clients and servers, but versions prior to DCE 1.1 did not fill in the transited field, and should be used with caution.
The [dbdefaults] section provides default values for the database specific parameters. It can also specify the configuration section under [dbmodules] section for database specific parameters used by the database library.(see dbmodules).
The following tags are used in this section:
Contains database specific parameters used by the database library. Each tag in the [dbmodules] section of the file names a configuration section for database specific parameters that can be referred to by a realm. The value of the tag is a subsection where the relations in that subsection define the database specific parameters.
For each section, the following tags may be specified in the subsection:
The following are pkinit-specific options.
Note that these values may be specified in [libdefaults]
as global defaults,
or within a realm-specific subsection of [libdefaults],
or may be specified as realm-specific values in the
[realms] section.
Also note that a realm-specific value over-rides, does not add to,
a generic [libdefaults] specification.
The search order is:
[libdefaults]
[libdefaults]
EXAMPLE.COM = {
pkinit_anchors = FILE:/usr/local/example.com.crt
}
[realms] section,
[realms]
OTHERREALM.ORG = {
pkinit_anchors = FILE:/usr/local/otherrealm.org.crt
}
[libdefaults] section.
[libdefaults]
pkinit_anchors = DIR:/usr/local/generic_trusted_cas/
The syntax for specifying Public Key identity, trust, and revocation information for pkinit is as follows:
*.crt and *.key, where the first part of the
file name is the same for matching pairs of certificate and
private key files. When a file with a name ending with .crt
is found, a matching file ending with .key is assumed
to contain the private key. If no such file is found, then
the certificate in the .crt is not used.
PKCS #12 format file, containing
the user's certificate and private key.
PKCS #11. If a value is encountered with not keyword, it
is assumed to be the module-name. If no module-name is
specified, the default is opensc-pkcs11.so.
slotid= and/or token= may be specified to force the use of a
particular smard card reader or token if there is more than one
available.
certid= and/or certlabel= may be specified to force the selection
of a particular certificate on the device. See the pkinit_cert_match
configuration option for more ways to select a particular certificate to
use for pkinit.
ENV:X509_PROXY, where environment
variable X509_PROXY has been set to FILE:/tmp/my_proxy.pem.
pkinit_require_crl_checking is false,
then verification succeeds.
However, if pkinit_require_crl_checking is true and
there is no CRL information available for the issuing CA,
then verification fails.
pkinit_require_crl_checking should be set to true
if the policy is such that up-to-date CRLs must be present for
every CA.
krb5.conf file are:
kpServerAuth is specified, a KDC certificate with the
id-kp-serverAuth EKU as used by Microsoft will be accepted.
none is specified, then the KDC certificate will not be
checked to verify it has an acceptable EKU. The use of this option
is not recommended.
The Subject and Issuer comparison strings are the RFC2253 string representations from the certificate Subject DN and Issuer DN values.
The syntax of the matching rules is:
[relation-operator]component-rule ...
where
&&, meaning all component rules must match,
or ||, meaning only one component rule must match.
The default is && if not specified.
<SUBJECT>regular-expression<ISSUER>regular-expression<SAN>regular-expression<EKU>extended-key-usage-listpkinitmsScLoginclientAuthemailProtection
<KU>key-usage-listdigitalSignaturekeyEncipherment
pkinit_cert_match = ||<SUBJECT>.*DoE.*<SAN>.*@EXAMPLE.COM
pkinit_cert_match = &&<EKU>msScLogin,clientAuth<ISSUER>.*DoE.*
pkinit_cert_match = <EKU>msScLogin,clientAuth<KU>digitalSignature
Here is an example of a generic krb5.conf file:
[libdefaults]
default_realm = ATHENA.MIT.EDU
default_tkt_enctypes = des3-hmac-sha1 des-cbc-crc
default_tgs_enctypes = des3-hmac-sha1 des-cbc-crc
dns_lookup_kdc = true
dns_lookup_realm = false
[realms]
ATHENA.MIT.EDU = {
kdc = kerberos.mit.edu
kdc = kerberos-1.mit.edu
kdc = kerberos-2.mit.edu:750
admin_server = kerberos.mit.edu
master_kdc = kerberos.mit.edu
default_domain = mit.edu
}
EXAMPLE.COM = {
kdc = kerberos.example.com
kdc = kerberos-1.example.com
admin_server = kerberos.example.com
}
OPENLDAP.MIT.EDU = {
kdc = kerberos.mit.edu
admin_server = kerberos.mit.edu
database_module = openldap_ldapconf
}
[domain_realm]
.mit.edu = ATHENA.MIT.EDU
mit.edu = ATHENA.MIT.EDU
[capaths]
ATHENA.MIT.EDU = {
EXAMPLE.COM = .
}
EXAMPLE.COM = {
ATHENA.MIT.EDU = .
}
[logging]
kdc = SYSLOG:INFO
admin_server = FILE=/var/kadm5.log
[dbdefaults]
ldap_kerberos_container_dn = cn=krbcontainer,o=mit
[dbmodules]
openldap_ldapconf = {
db_library = kldap
ldap_kerberos_container_dn = cn=krbcontainer,o=mit
ldap_kdc_dn = "cn=krbadmin,o=mit"
# this object needs to have read rights on
# the realm container, principal container and realm sub-trees
ldap_kadmind_dn = "cn=krbadmin,o=mit"
# this object needs to have read and write rights on
# the realm container, principal container and realm sub-trees
ldap_service_password_file = /etc/kerberos/service.keyfile
ldap_servers = ldaps://kerberos.mit.edu
ldap_conns_per_server = 5
}
The kdc.conf file contains KDC configuration information,
including defaults used when issuing Kerberos tickets. Normally, you
should install your kdc.conf file in the directory
/usr/local/var/krb5kdc. You can override the default
location by setting the environment variable KRB5_KDC_PROFILE.
The kdc.conf file is set up in the same format as the
krb5.conf file. (See krb5.conf.) The kdc.conf file
may contain any or all of the following three sections:
The following relation is defined in the [kdcdefaults] section:
If you wish to change this (which we do not recommend, because the current implementation has little protection against denial-of-service attacks), the standard port number assigned for Kerberos TCP traffic is port 88.
Each tag in the [realms] section of the file names a Kerberos realm. The value of the tag is a subsection where the relations in that subsection define KDC parameters for that particular realm.
For each realm, the following tags may be specified in the [realms] subsection:
/usr/local/var/krb5kdc/kadm5.acl.
kadmind4 and v5passwdd use to authenticate to
the database. The default is /usr/local/var/krb5kdc/kadm5.keytab.
/usr/local/var/krb5kdc/principal.
There are a number of possible flags:
kdb5_util stash). The default is
/usr/local/var/krb5kdc/.k5.REALM, where REALM is the
Kerberos realm.
kadmin
will have keys of these types. The default value for this tag is
des3-hmac-sha1:normal des-cbc-crc:normal. For lists of possible values, see
Supported Encryption Types and Salts.
true, false). If set to true, the
KDC will check the list of transited realms for cross-realm tickets
against the transit path computed from the realm names and the
capaths section of its krb5.conf file; if the path in the
ticket to be issued contains any realms not in the computed path, the
ticket will not be issued, and an error will be returned to the client
instead. If this value is set to false, such tickets will be
issued anyways, and it will be left up to the application server to
validate the realm transit path.
If the disable-transited-check flag is set in the incoming
request, this check is not performed at all. Having the
reject_bad_transit option will cause such ticket requests to be
rejected always.
This transit path checking and config file option currently apply only to TGS requests.
Earlier versions of the MIT release (before 1.2.3) had bugs in the application server support such that the server-side checks may not be performed correctly. We recommend turning this option on, unless you know that all application servers in this realm have been updated to fixed versions of the software, and for whatever reason, you don't want the KDC to do the validation.
This is a per-realm option so that multiple-realm KDCs may control it separately for each realm, in case (for example) one realm has had the software on its application servers updated but another has not.
This option defaults to true.
The following are pkinit-specific options.
Note that these values may be specified in [kdcdefaults]
as global defaults,
or within a realm-specific subsection of [realms].
Also note that a realm-specific value over-rides, does not add to,
a generic [kdcdefaults] specification.
The search order is:
[realms]
[realms]
EXAMPLE.COM = {
pkinit_anchors = FILE:/usr/local/example.com.crt
}
[kdcdefaults] section.
[kdcdefaults]
pkinit_anchors = DIR:/usr/local/generic_trusted_cas/
For information about the syntax of some of these options, see See pkinit identity syntax.
pkinit_require_crl_checking is false,
then verification succeeds.
However, if pkinit_require_crl_checking is true and
there is no CRL information available for the issuing CA,
then verification fails.
pkinit_require_crl_checking should be set to true
if the policy is such that up-to-date CRLs must be present for
every CA.
The default is false.
Without this option, the KDC will only
accept certificates with the id-pkinit-san as defined in RFC4556.
There is currently no option to disable SAN checking in the KDC.
kdc.conf file are:
scLogin is specified, client certificates with the
Microsoft Smart Card Login EKU (id-ms-kp-sc-logon) will be accepted.
none is specified, then client certificates will not be
checked to verify they have an acceptable EKU.
The use of this option is not recommended.
Here's an example of a kdc.conf file:
[kdcdefaults]
kdc_ports = 88
[realms]
ATHENA.MIT.EDU = {
kadmind_port = 749
max_life = 12h 0m 0s
max_renewable_life = 7d 0h 0m 0s
master_key_type = des3-hmac-sha1
supported_enctypes = des3-hmac-sha1:normal des-cbc-crc:normal des-cbc-crc:v4
}
[logging]
kdc = FILE:/usr/local/var/krb5kdc/kdc.log
admin_server = FILE:/usr/local/var/krb5kdc/kadmin.log
Mapping hostnames onto Kerberos realms is done in one of two ways.
The first mechanism, which has been in use for years in MIT-based
Kerberos distributions, works through a set of rules in
the krb5.conf configuration file. (See krb5.conf.) You can
specify mappings for an entire domain or subdomain, and/or on a
hostname-by-hostname basis. Since greater specificity takes precedence,
you would do this by specifying the mappings for a given domain or
subdomain and listing the exceptions.
The second mechanism works by looking up the information in special
TXT records in the Domain Name Service. This is currently not
used by default because security holes could result if the DNS TXT
records were spoofed. If this mechanism is enabled on the client,
it will try to look up a TXT record for the DNS name formed by
putting the prefix _kerberos in front of the hostname in question.
If that record is not found, it will try using _kerberos and the
host's domain name, then its parent domain, and so forth. So for the
hostname BOSTON.ENGINEERING.FOOBAR.COM, the names looked up would be:
_kerberos.boston.engineering.foobar.com
_kerberos.engineering.foobar.com
_kerberos.foobar.com
_kerberos.com
The value of the first TXT record found is taken as the realm name. (Obviously, this doesn't work all that well if a host and a subdomain have the same name, and different realms. For example, if all the hosts in the ENGINEERING.FOOBAR.COM domain are in the ENGINEERING.FOOBAR.COM realm, but a host named ENGINEERING.FOOBAR.COM is for some reason in another realm. In that case, you would set up TXT records for all hosts, rather than relying on the fallback to the domain name.)
Even if you do not choose to use this mechanism within your site, you may wish to set it up anyway, for use when interacting with other sites.
MIT recommends that your KDCs have a predefined set of
CNAME records (DNS hostname aliases), such as kerberos
for the master KDC and
kerberos-1, kerberos-2, ... for the
slave KDCs. This way, if you need to swap a machine, you only need to
change a DNS entry, rather than having to change hostnames.
A new mechanism for locating KDCs of a realm through DNS has been added
to the MIT Kerberos V5 distribution. A relatively new
record type called SRV has been added to DNS. Looked up by a
service name and a domain name, these records indicate the hostname and
port number to contact for that service, optionally with weighting and
prioritization. (See RFC 2782 if you want more information. You can
follow the example below for straightforward cases.)
The use with Kerberos is fairly straightforward. The domain name used in the SRV record name is the domain-style Kerberos realm name. (It is possible to have Kerberos realm names that are not DNS-style names, but we don't recommend it for Internet use, and our code does not support it well.) Several different Kerberos-related service names are used:
_kerberos._udp_kerberos._tcp_kerberos-master._udpIf you have only one KDC, or for whatever reason there is no accessible
KDC that would get database changes faster than the others, you do not
need to define this entry.
_kerberos-adm._tcpkadmin program and related utilities. For now, you
will also need the admin_server entry in krb5.conf.
(See krb5.conf.)
_kpasswd._udp_kerberos-iv._udpBe aware, however, that the DNS SRV specification requires that the hostnames listed be the canonical names, not aliases. So, for example, you might include the following records in your (BIND-style) zone file:
$ORIGIN foobar.com.
_kerberos TXT "FOOBAR.COM"
kerberos CNAME daisy
kerberos-1 CNAME use-the-force-luke
kerberos-2 CNAME bunny-rabbit
_kerberos._udp SRV 0 0 88 daisy
SRV 0 0 88 use-the-force-luke
SRV 0 0 88 bunny-rabbit
_kerberos-master._udp SRV 0 0 88 daisy
_kerberos-adm._tcp SRV 0 0 749 daisy
_kpasswd._udp SRV 0 0 464 daisy
As with the DNS-based mechanism for determining the Kerberos realm of a
host, we recommend distributing the information this way for use by
other sites that may want to interact with yours using Kerberos, even if
you don't immediately make use of it within your own site. If you
anticipate installing a very large number of machines on which it will
be hard to update the Kerberos configuration files, you may wish to do
all of your Kerberos service lookups via DNS and not put the information
(except for admin_server as noted above) in future versions of
your krb5.conf files at all. Eventually, we hope to phase out
the listing of server hostnames in the client-side configuration files;
making preparations now will make the transition easier in the future.
Your Kerberos database contains all of your realm's Kerberos principals,
their passwords, and other administrative information about each
principal. For the most part, you will use the kdb5_util program
to manipulate the Kerberos database as a whole, and the kadmin
program to make changes to the entries in the database. (One notable
exception is that users will use the kpasswd program to change
their own passwords.) The kadmin program has its own
command-line interface, to which you type the database administrating
commands.
Kdb5_util provides a means to create, delete, load, or dump a
Kerberos database. It also includes a command to stash a copy of the
master database key in a file on a KDC, so that the KDC can authenticate
itself to the kadmind and krb5kdc daemons at boot time.
Kadmin provides for the maintenance of Kerberos principals, KADM5
policies, and service key tables (keytabs). It exists as both a
Kerberos client, kadmin, using Kerberos authentication and an
RPC, to operate securely from anywhere on the network, and as a local
client, kadmin.local, intended to run directly on the KDC without
Kerberos authentication. kadmin.local need not run on the kdc if
the database is LDAP. Other than the fact that the remote client uses
Kerberos to authenticate the person using it, the functionalities of the two
versions are identical. The local version is necessary to enable you to set up
enough of the database to be able to use the remote version.
It replaces the now obsolete kdb5_edit (except for
database dump and load, which are provided by kdb5_util).
The remote version authenticates to the KADM5 server using the service
principal kadmin/admin. If the credentials cache contains a
ticket for the kadmin/admin principal, and the -c ccache
option is specified, that ticket is used to authenticate to KADM5.
Otherwise, the -p and -k options are used to specify the
client Kerberos principal name used to authenticate. Once kadmin has
determined the principal name, it requests a kadmin/admin
Kerberos service ticket from the KDC, and uses that service ticket to
authenticate to KADM5.
You can invoke kadmin or kadmin.local with any of the
following options:
kadmin will append admin to
either the primary principal name, the environment variable USER, or to
the username obtained from getpwuid, in order of preference.
kadmin. This is useful for writing
scripts that pass specific queries to kadmin.
You can invoke kadmin with any of the following options:
kadmin/admin
service, which can be acquired with the kinit program. If this
option is not specified, kadmin requests a new service ticket
from the KDC, and stores it in its own temporary ccache.
Note: This database specific argument is applicable only to kadmin.local
and the KADM5 server.
You can invoke kadmin.local with an of the follwing options:
Many of the kadmin commands take a duration or time as an
argument. The date can appear in a wide variety of formats, such as:
"15 minutes"
"7 days"
"1 month"
"2 hours"
"400000 seconds"
"next year"
"this Monday"
"next Monday"
yesterday
tomorrow
now
"second Monday"
fortnight
"3/31/1992 10:00:07 PST"
"January 23, 2007 10:05pm"
"22:00 GMT"
Note that if the date specification contains spaces, you must enclose it in double quotes. Note also that you cannot use a number without a unit. (I.e., “"60 seconds"” is correct, but “60” is incorrect.) All keywords are case-insensitive. The following is a list of all of the allowable keywords.
kadmin recognizes abbreviations for most of the world's time
zones. A complete listing appears in kadmin Time Zones.
Each entry in the Kerberos database contains a Kerberos principal (see Definitions) and the attributes and policies associated with that principal.