MIT Kerberos Documentation

kadmin

SYNOPSIS

kadmin [-O|-N] [-r realm] [-p principal] [-q query] [[-c cache_name]|[-k [-t keytab]]|-n] [-w password] [-s admin_server[:port]]

kadmin.local [-r realm] [-p principal] [-q query] [-d dbname] [-e enc:salt ...] [-m] [-x db_args]

DESCRIPTION

kadmin and kadmin.local are command-line interfaces to the Kerberos V5 administration system. They provide nearly identical functionalities; the difference is that kadmin.local directly accesses the KDC database, while kadmin performs operations using kadmind. Except as explicitly noted otherwise, this man page will use “kadmin” to refer to both versions. kadmin provides for the maintenance of Kerberos principals, password policies, and service key tables (keytabs).

The remote kadmin client uses Kerberos to authenticate to kadmind using the service principal kadmin/ADMINHOST (where ADMINHOST is the fully-qualified hostname of the admin server) or kadmin/admin. If the credentials cache contains a ticket for one of these principals, and the -c credentials_cache option is specified, that ticket is used to authenticate to kadmind. 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 service ticket from the KDC, and uses that service ticket to authenticate to kadmind.

Since kadmin.local directly accesses the KDC database, it usually must be run directly on the master KDC with sufficient permissions to read the KDC database. If the KDC database uses the LDAP database module, kadmin.local can be run on any host which can access the LDAP server.

OPTIONS

-r realm
Use realm as the default database realm.
-p principal
Use principal to authenticate. Otherwise, kadmin will append /admin to the primary principal name of the default ccache, the value of the USER environment variable, or the username as obtained with getpwuid, in order of preference.
-k
Use a keytab to decrypt the KDC response instead of prompting for a password. In this case, the default principal will be host/hostname. If there is no keytab specified with the -t option, then the default keytab will be used.
-t keytab
Use keytab to decrypt the KDC response. This can only be used with the -k option.
-n
Requests anonymous processing. Two types of anonymous principals are supported. For fully anonymous Kerberos, configure PKINIT on the KDC and configure pkinit_anchors in the client’s krb5.conf. Then use the -n option with a principal of the form @REALM (an empty principal name followed by the at-sign and a realm name). If permitted by the KDC, an anonymous ticket will be returned. A second form of anonymous tickets is supported; these realm-exposed tickets hide the identity of the client but not the client’s realm. For this mode, use kinit -n with a normal principal name. If supported by the KDC, the principal (but not realm) will be replaced by the anonymous principal. As of release 1.8, the MIT Kerberos KDC only supports fully anonymous operation.
-c credentials_cache
Use credentials_cache as the credentials cache. The cache should contain a service ticket for the kadmin/ADMINHOST (where ADMINHOST is the fully-qualified hostname of the admin server) or kadmin/admin service; it 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.
-w password
Use password instead of prompting for one. Use this option with care, as it may expose the password to other users on the system via the process list.
-q query
Perform the specified query and then exit. This can be useful for writing scripts.
-d dbname
Specifies the name of the KDC database. This option does not apply to the LDAP database module.
-s admin_server[:port]
Specifies the admin server which kadmin should contact.
-m
If using kadmin.local, prompt for the database master password instead of reading it from a stash file.
-eenc:salt ...”
Sets the keysalt list to be used for any new keys created. See Keysalt lists in kdc.conf for a list of possible values.
-O
Force use of old AUTH_GSSAPI authentication flavor.
-N
Prevent fallback to AUTH_GSSAPI authentication flavor.
-x db_args
Specifies the database specific arguments. See the next section for supported options.

DATABASE OPTIONS

Database options can be used to override database-specific defaults. Supported options for the DB2 module are:

-x dbname=*filename*
Specifies the base filename of the DB2 database.

Supported options for the LDAP module are:

-x host=ldapuri
Specifies the LDAP server to connect to by a LDAP URI.
-x binddn=bind_dn
Specifies the DN used to bind to the LDAP server.
-x bindpwd=password
Specifies the password or SASL secret used to bind to the LDAP server. Using this option may expose the password to other users on the system via the process list; to avoid this, instead stash the password using the stashsrvpw command of kdb5_ldap_util.
-x sasl_mech=mechanism
Specifies the SASL mechanism used to bind to the LDAP server. The bind DN is ignored if a SASL mechanism is used. New in release 1.13.
-x sasl_authcid=name
Specifies the authentication name used when binding to the LDAP server with a SASL mechanism, if the mechanism requires one. New in release 1.13.
-x sasl_authzid=name
Specifies the authorization name used when binding to the LDAP server with a SASL mechanism. New in release 1.13.
-x sasl_realm=realm
Specifies the realm used when binding to the LDAP server with a SASL mechanism, if the mechanism uses one. New in release 1.13.
-x debug=level
sets the OpenLDAP client library debug level. level is an integer to be interpreted by the library. Debugging messages are printed to standard error. New in release 1.12.

COMMANDS

When using the remote client, available commands may be restricted according to the privileges specified in the kadm5.acl file on the admin server.

add_principal

add_principal [options] newprinc

Creates the principal newprinc, prompting twice for a password. If no password policy is specified with the -policy option, and the policy named default is assigned to the principal if it exists. However, creating a policy named default will not automatically assign this policy to previously existing principals. This policy assignment can be suppressed with the -clearpolicy option.

This command requires the add privilege.

Aliases: addprinc, ank

Options:

-expire expdate
(getdate time string) The expiration date of the principal.
-pwexpire pwexpdate
(getdate time string) The password expiration date.
-maxlife maxlife
(getdate time string) The maximum ticket life for the principal.
-maxrenewlife maxrenewlife
(getdate time string) The maximum renewable life of tickets for the principal.
-kvno kvno
The initial key version number.
-policy policy
The password policy used by this principal. If not specified, the policy default is used if it exists (unless -clearpolicy is specified).
-clearpolicy
Prevents any policy from being assigned when -policy is not specified.
{-|+}allow_postdated
-allow_postdated prohibits this principal from obtaining postdated tickets. +allow_postdated clears this flag.
{-|+}allow_forwardable
-allow_forwardable prohibits this principal from obtaining forwardable tickets. +allow_forwardable clears this flag.
{-|+}allow_renewable
-allow_renewable prohibits this principal from obtaining renewable tickets. +allow_renewable clears this flag.
{-|+}allow_proxiable
-allow_proxiable prohibits this principal from obtaining proxiable tickets. +allow_proxiable clears this flag.
{-|+}allow_dup_skey
-allow_dup_skey disables user-to-user authentication for this principal by prohibiting this principal from obtaining a session key for another user. +allow_dup_skey clears this flag.
{-|+}requires_preauth
+requires_preauth requires this principal to preauthenticate before being allowed to kinit. -requires_preauth clears this flag. When +requires_preauth is set on a service principal, the KDC will only issue service tickets for that service principal if the client’s initial authentication was performed using preauthentication.
{-|+}requires_hwauth
+requires_hwauth requires this principal to preauthenticate using a hardware device before being allowed to kinit. -requires_hwauth clears this flag. When +requires_hwauth is set on a service principal, the KDC will only issue service tickets for that service principal if the client’s initial authentication was performed using a hardware device to preauthenticate.
{-|+}ok_as_delegate
+ok_as_delegate sets the okay as delegate flag on tickets issued with this principal as the service. Clients may use this flag as a hint that credentials should be delegated when authenticating to the service. -ok_as_delegate clears this flag.
{-|+}allow_svr
-allow_svr prohibits the issuance of service tickets for this principal. +allow_svr clears this flag.
{-|+}allow_tgs_req
-allow_tgs_req specifies that a Ticket-Granting Service (TGS) request for a service ticket for this principal is not permitted. +allow_tgs_req clears this flag.
{-|+}allow_tix
-allow_tix forbids the issuance of any tickets for this principal. +allow_tix clears this flag.
{-|+}needchange
+needchange forces a password change on the next initial authentication to this principal. -needchange clears this flag.
{-|+}password_changing_service
+password_changing_service marks this principal as a password change service principal.
{-|+}ok_to_auth_as_delegate
+ok_to_auth_as_delegate allows this principal to acquire forwardable tickets to itself from arbitrary users, for use with constrained delegation.
{-|+}no_auth_data_required
+no_auth_data_required prevents PAC or AD-SIGNEDPATH data from being added to service tickets for the principal.
-randkey
Sets the key of the principal to a random value.
-nokey
Causes the principal to be created with no key. New in release 1.12.
-pw password
Sets the password of the principal to the specified string and does not prompt for a password. Note: using this option in a shell script may expose the password to other users on the system via the process list.
-e enc:salt,...
Uses the specified keysalt list for setting the keys of the principal. See Keysalt lists in kdc.conf for a list of possible values.
-x db_princ_args

Indicates database-specific options. The options for the LDAP database module are:

-x dn=dn
Specifies the LDAP object that will contain the Kerberos principal being created.
-x linkdn=dn
Specifies the LDAP object to which the newly created Kerberos principal object will point.
-x containerdn=container_dn
Specifies the container object under which the Kerberos principal is to be created.
-x tktpolicy=policy
Associates a ticket policy to the Kerberos principal.

Note

  • The containerdn and linkdn options cannot be specified with the dn option.
  • If the dn or containerdn options are not specified while adding the principal, the principals are created under the principal container configured in the realm or the realm container.
  • dn and containerdn should be within the subtrees or principal container configured in the realm.

Example:

kadmin: addprinc jennifer
WARNING: no policy specified for "jennifer@ATHENA.MIT.EDU";
defaulting to no policy.
Enter password for principal jennifer@ATHENA.MIT.EDU:
Re-enter password for principal jennifer@ATHENA.MIT.EDU:
Principal "jennifer@ATHENA.MIT.EDU" created.
kadmin:

modify_principal

modify_principal [options] principal

Modifies the specified principal, changing the fields as specified. The options to add_principal also apply to this command, except for the -randkey, -pw, and -e options. In addition, the option -clearpolicy will clear the current policy of a principal.

This command requires the modify privilege.

Alias: modprinc

Options (in addition to the addprinc options):

-unlock
Unlocks a locked principal (one which has received too many failed authentication attempts without enough time between them according to its password policy) so that it can successfully authenticate.

rename_principal

rename_principal [-force] old_principal new_principal

Renames the specified old_principal to new_principal. This command prompts for confirmation, unless the -force option is given.

This command requires the add and delete privileges.

Alias: renprinc

delete_principal

delete_principal [-force] principal

Deletes the specified principal from the database. This command prompts for deletion, unless the -force option is given.

This command requires the delete privilege.

Alias: delprinc

change_password

change_password [options] principal

Changes the password of principal. Prompts for a new password if neither -randkey or -pw is specified.

This command requires the changepw privilege, or that the principal running the program is the same as the principal being changed.

Alias: cpw

The following options are available:

-randkey
Sets the key of the principal to a random value.
-pw password
Set the password to the specified string. Using this option in a script may expose the password to other users on the system via the process list.
-e enc:salt,...
Uses the specified keysalt list for setting the keys of the principal. See Keysalt lists in kdc.conf for a list of possible values.
-keepold
Keeps the existing keys in the database. This flag is usually not necessary except perhaps for krbtgt principals.

Example:

kadmin: cpw systest
Enter password for principal systest@BLEEP.COM:
Re-enter password for principal systest@BLEEP.COM:
Password for systest@BLEEP.COM changed.
kadmin:

purgekeys

purgekeys [-all|-keepkvno oldest_kvno_to_keep] principal

Purges previously retained old keys (e.g., from change_password -keepold) from principal. If -keepkvno is specified, then only purges keys with kvnos lower than oldest_kvno_to_keep. If -all is specified, then all keys are purged. The -all option is new in release 1.12.

This command requires the modify privilege.

get_principal

get_principal [-terse] principal

Gets the attributes of principal. With the -terse option, outputs fields as quoted tab-separated strings.

This command requires the inquire privilege, or that the principal running the the program to be the same as the one being listed.

Alias: getprinc

Examples:

kadmin: getprinc tlyu/admin
Principal: tlyu/admin@BLEEP.COM
Expiration date: [never]
Last password change: Mon Aug 12 14:16:47 EDT 1996
Password expiration date: [none]
Maximum ticket life: 0 days 10:00:00
Maximum renewable life: 7 days 00:00:00
Last modified: Mon Aug 12 14:16:47 EDT 1996 (bjaspan/admin@BLEEP.COM)
Last successful authentication: [never]
Last failed authentication: [never]
Failed password attempts: 0
Number of keys: 2
Key: vno 1, des-cbc-crc
Key: vno 1, des-cbc-crc:v4
Attributes:
Policy: [none]

kadmin: getprinc -terse systest
systest@BLEEP.COM   3    86400     604800    1
785926535 753241234 785900000
tlyu/admin@BLEEP.COM     786100034 0    0
kadmin:

list_principals

list_principals [expression]

Retrieves all or some principal names. expression is a shell-style glob expression that can contain the wild-card characters ?, *, and []. All principal names matching the expression are printed. If no expression is provided, all principal names are printed. If the expression does not contain an @ character, an @ character followed by the local realm is appended to the expression.

This command requires the list privilege.

Alias: listprincs, get_principals, get_princs

Example:

kadmin:  listprincs test*
test3@SECURE-TEST.OV.COM
test2@SECURE-TEST.OV.COM
test1@SECURE-TEST.OV.COM
testuser@SECURE-TEST.OV.COM
kadmin:

get_strings

get_strings principal

Displays string attributes on principal.

This command requires the inquire privilege.

Alias: getstr

set_string

set_string principal name value

Sets a string attribute on principal. String attributes are used to supply per-principal configuration to the KDC and some KDC plugin modules. The following string attribute names are recognized by the KDC:

session_enctypes
Specifies the encryption types supported for session keys when the principal is authenticated to as a server. See Encryption types in kdc.conf for a list of the accepted values.
otp
Enables One Time Passwords (OTP) preauthentication for a client principal. The value is a JSON string representing an array of objects, each having optional type and username fields.

This command requires the modify privilege.

Alias: setstr

Example:

set_string host/foo.mit.edu session_enctypes aes128-cts
set_string user@FOO.COM otp [{"type":"hotp","username":"custom"}]

del_string

del_string principal key

Deletes a string attribute from principal.

This command requires the delete privilege.

Alias: delstr

add_policy

add_policy [options] policy

Adds a password policy named policy to the database.

This command requires the add privilege.

Alias: addpol

The following options are available:

-maxlife time
(getdate time string) Sets the maximum lifetime of a password.
-minlife time
(getdate time string) Sets the minimum lifetime of a password.
-minlength length
Sets the minimum length of a password.
-minclasses number
Sets the minimum number of character classes required in a password. The five character classes are lower case, upper case, numbers, punctuation, and whitespace/unprintable characters.
-history number
Sets the number of past keys kept for a principal. This option is not supported with the LDAP KDC database module.
-maxfailure maxnumber
Sets the number of authentication failures before the principal is locked. Authentication failures are only tracked for principals which require preauthentication. The counter of failed attempts resets to 0 after a successful attempt to authenticate. A maxnumber value of 0 (the default) disables lockout.
-failurecountinterval failuretime
(getdate time string) Sets the allowable time between authentication failures. If an authentication failure happens after failuretime has elapsed since the previous failure, the number of authentication failures is reset to 1. A failuretime value of 0 (the default) means forever.
-lockoutduration lockouttime
(getdate time string) Sets the duration for which the principal is locked from authenticating if too many authentication failures occur without the specified failure count interval elapsing. A duration of 0 (the default) means the principal remains locked out until it is administratively unlocked with modprinc -unlock.
-allowedkeysalts
Specifies the key/salt tuples supported for long-term keys when setting or changing a principal’s password/keys. See Keysalt lists in kdc.conf for a list of the accepted values, but note that key/salt tuples must be separated with commas (‘,’) only. To clear the allowed key/salt policy use a value of ‘-‘.

Example:

kadmin: add_policy -maxlife "2 days" -minlength 5 guests
kadmin:

modify_policy

modify_policy [options] policy

Modifies the password policy named policy. Options are as described for add_policy.

This command requires the modify privilege.

Alias: modpol

delete_policy

delete_policy [-force] policy

Deletes the password policy named policy. Prompts for confirmation before deletion. The command will fail if the policy is in use by any principals.

This command requires the delete privilege.

Alias: delpol

Example:

kadmin: del_policy guests
Are you sure you want to delete the policy "guests"?
(yes/no): yes
kadmin:

get_policy

get_policy [ -terse ] policy

Displays the values of the password policy named policy. With the -terse flag, outputs the fields as quoted strings separated by tabs.

This command requires the inquire privilege.

Alias: getpol

Examples:

kadmin: get_policy admin
Policy: admin
Maximum password life: 180 days 00:00:00
Minimum password life: 00:00:00
Minimum password length: 6
Minimum number of password character classes: 2
Number of old keys kept: 5
Reference count: 17

kadmin: get_policy -terse admin
admin     15552000  0    6    2    5    17
kadmin:

The “Reference count” is the number of principals using that policy. With the LDAP KDC database module, the reference count field is not meaningful.

list_policies

list_policies [expression]

Retrieves all or some policy names. expression is a shell-style glob expression that can contain the wild-card characters ?, *, and []. All policy names matching the expression are printed. If no expression is provided, all existing policy names are printed.

This command requires the list privilege.

Aliases: listpols, get_policies, getpols.

Examples:

kadmin:  listpols
test-pol
dict-only
once-a-min
test-pol-nopw

kadmin:  listpols t*
test-pol
test-pol-nopw
kadmin:

ktadd

ktadd [options] principal
ktadd [options] -glob princ-exp

Adds a principal, or all principals matching princ-exp, to a keytab file. Each principal’s keys are randomized in the process. The rules for princ-exp are described in the list_principals command.

This command requires the inquire and changepw privileges. With the -glob form, it also requires the list privilege.

The options are:

-k[eytab] keytab
Use keytab as the keytab file. Otherwise, the default keytab is used.
-e enc:salt,...
Uses the specified keysalt list for setting the new keys of the principal. See Keysalt lists in kdc.conf for a list of possible values.
-q
Display less verbose information.
-norandkey
Do not randomize the keys. The keys and their version numbers stay unchanged. This option is only available in kadmin.local, and cannot be specified in combination with the -e option.

An entry for each of the principal’s unique encryption types is added, ignoring multiple keys with the same encryption type but different salt types.

Example:

kadmin: ktadd -k /tmp/foo-new-keytab host/foo.mit.edu
Entry for principal host/foo.mit.edu@ATHENA.MIT.EDU with kvno 3,
     encryption type aes256-cts-hmac-sha1-96 added to keytab
     FILE:/tmp/foo-new-keytab
kadmin:

ktremove

ktremove [options] principal [kvno | all | old]

Removes entries for the specified principal from a keytab. Requires no permissions, since this does not require database access.

If the string “all” is specified, all entries for that principal are removed; if the string “old” is specified, all entries for that principal except those with the highest kvno are removed. Otherwise, the value specified is parsed as an integer, and all entries whose kvno match that integer are removed.

The options are:

-k[eytab] keytab
Use keytab as the keytab file. Otherwise, the default keytab is used.
-q
Display less verbose information.

Example:

kadmin: ktremove kadmin/admin all
Entry for principal kadmin/admin with kvno 3 removed from keytab
     FILE:/etc/krb5.keytab
kadmin:

lock

Lock database exclusively. Use with extreme caution! This command only works with the DB2 KDC database module.

unlock

Release the exclusive database lock.

list_requests

Lists available for kadmin requests.

Aliases: lr, ?

quit

Exit program. If the database was locked, the lock is released.

Aliases: exit, q

HISTORY

The kadmin program was originally written by Tom Yu at MIT, as an interface to the OpenVision Kerberos administration program.

SEE ALSO

kpasswd, kadmind