kadmin — MIT Kerberos Documentation

# MIT Kerberos Documentation

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# kadmin

## SYNOPSIS

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

kadmin.local [-r realm] [-p principal] [-q query] [-d dbname] [-e enc:salt …] [-m] [-x db_args] [command 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/admin` or `kadmin/ADMINHOST` (where ADMINHOST is the fully-qualified hostname of the admin server). 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 primary 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/admin` or `kadmin/ADMINHOST` (where ADMINHOST is the fully-qualified hostname of the admin server) 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.

-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.

-e “enc: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.

Starting with release 1.14, if any command-line arguments remain after the options, they will be treated as a single query to be executed. This mode of operation is intended for scripts and behaves differently from the interactive mode in several respects:

- Query arguments are split by the shell, not by kadmin.

- Informational and warning messages are suppressed. Error messages and query output (e.g. for get_principal) will still be displayed.

- Confirmation prompts are disabled (as if -force was given). Password prompts will still be issued as required.

- The exit status will be non-zero if the query fails.

The -q option does not carry these behavior differences; the query will be processed as if it was entered interactively. The -q option cannot be used in combination with a query in the remaining arguments.

## 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.

> -x lockiter

>   Make iteration operations hold the lock for the duration of the entire operation, rather than temporarily releasing the lock while handling each principal. This is the default behavior, but this option exists to allow command line override of a [dbmodules] setting. First introduced in release 1.13.

> -x unlockiter

>   Make iteration operations unlock the database for each principal, instead of holding the lock for the duration of the entire operation. First introduced in release 1.13.

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

  (Time duration or getdate time string) The maximum ticket life for the principal.

-maxrenewlife maxrenewlife

  (Time duration or 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 others from obtaining a service ticket encrypted in this principal’s TGT session key. +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. In release 1.17 and later, user-to-user service tickets are still allowed unless the -allow_dup_skey flag is also set. +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.

{-|+}lockdown_keys

  +lockdown_keys prevents keys for this principal from leaving the KDC via kadmind. The chpass and extract operations are denied for a principal with this attribute. The chrand operation is allowed, but will not return the new keys. The delete and rename operations are also denied if this attribute is set, in order to prevent a malicious administrator from replacing principals like krbtgt/* or kadmin/* with new principals without the attribute. This attribute can be set via the network protocol, but can only be removed using kadmin.local.

-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
    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

### add_alias

> add_alias alias_princ target_princ

Create an alias alias_princ pointing to target_princ. Aliases may be chained (that is, target_princ may itself be an alias) up to a depth of 10.

This command requires the add privilege for alias_princ and the modify privilege for target_princ.

(New in release 1.22.)

Aliases: alias

### delete_principal

> delete_principal [-force] principal

Deletes the specified principal or alias 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: [never]
    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: 1
    Key: vno 1, aes256-cts-hmac-sha384-192
    MKey: vno 1
    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, getprincs

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: getstrs

### 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:

require_auth

  Specifies an authentication indicator which is required to authenticate to the principal as a service. Multiple indicators can be specified, separated by spaces; in this case any of the specified indicators will be accepted. (New in release 1.14.)

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.

pkinit_cert_match

  Specifies a matching expression that defines the certificate attributes required for the client certificate used by the principal during PKINIT authentication. The matching expression is in the same format as those used by the pkinit_cert_match option in krb5.conf. (New in release 1.16.)

pac_privsvr_enctype

  Forces the encryption type of the PAC KDC checksum buffers to the specified encryption type for tickets issued to this server, by deriving a key from the local krbtgt key if it is of a different encryption type. It may be necessary to set this value to “aes256-sha1” on the cross-realm krbtgt entry for an Active Directory realm when using aes-sha2 keys on the local krbtgt entry.

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"":""al""}]"

### 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

  (Time duration or getdate time string) Sets the maximum lifetime of a password.

-minlife time

  (Time duration or 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

  (Time duration or 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

  (Time duration or 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 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.

Alias: xst

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.

Alias: ktrem

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.

## ENVIRONMENT

See kerberos for a description of Kerberos environment variables.

## SEE ALSO

kpasswd, kadmind, kerberos