Authen::Krb5::Admin(3) Perl extension for MIT Kerberos 5 admin interface

SYNOPSIS


use Authen::Krb5::Admin;
use Authen::Krb5::Admin qw(:constants);

DESCRIPTION

The Authen::Krb5::Admin Perl module is an object-oriented interface to the Kerberos 5 admin server. Currently only MIT KDCs are supported, but the author envisions seamless integration with other KDCs.

The following classes are provided by this module:

 Authen::Krb5::Admin             handle for performing kadmin operations
 Authen::Krb5::Admin::Config     kadmin configuration parameters
 Authen::Krb5::Admin::Key        key data from principal object
 Authen::Krb5::Admin::Policy     kadmin policies
 Authen::Krb5::Admin::Principal  kadmin principals

Configuration Parameters, Policies, and Principals

Before performing kadmin operations, the programmer must construct objects to represent the entities to be manipulated. Each of the classes

        Authen::Krb5::Admin::Config
        Authen::Krb5::Admin::Key
        Authen::Krb5::Admin::Policy
        Authen::Krb5::Admin::Principal

has a constructor new which takes no arguments (except for the class name). The new object may be populated using accessor methods, each of which is named for the C struct element it represents. Methods always return the current value of the attribute, except for the policy_clear method, which returns nothing. If a value is provided, the attribute is set to that value, and the new value is returned.

All attributes may be modified in each object, but read-only attributes will be ignored when performing kadmin operations. These attributes are indicated in the documentation for their accessor methods.

Each of the C functions that manipulate kadm5 principal and policy structures takes a mask argument to indicate which fields should be taken into account. The Perl accessor methods take care of the mask for you, assuming that when you change a value, you will eventually want it changed on the server.

Flags for the read-only fields do not get set automatically because they would result in a bad mask error when performing kadmin operations.

Some writable attributes are not allowed to have their masks set for certain operations. For example, KADM5_POLICY may not be set during a create_principal operation, but since the Perl module sets that flag automatically when you set the policy attribute of the principal object, a bad mask error would result. Therefore, some kadmin operations automatically clear certain flags first.

Though you should never have to, you can manipulate the mask on your own using the mask methods and the flags associated with each attribute (indicated in curly braces ({}s) below). Use the tag :constants to request that the flag constants (and all other constants) be made available (see Exporter(3)).

Authen::Krb5::Admin::Config
This class is used to configure a kadmin connection. Without this object, Authen::Krb5::Admin constructors will default to the configuration defined in the Kerberos 5 profile (/etc/krb5.conf by default). So this object is usually only needed when selecting alternate realms or contacting a specific, non-default server.

The only methods in this class are the constructor (new, described above) and the following accessor methods.

admin_server {KADM5_CONFIG_ADMIN_SERVER}
Admin server hostname
kadmind_port {KADM5_CONFIG_KADMIND_PORT}
Admin server port number
kpasswd_port {KADM5_CONFIG_KPASSWD_PORT}
Kpasswd server port number
mask
Mask (described above)
profile {KADM5_CONFIG_PROFILE}
Kerberos 5 configuration profile
realm {KADM5_CONFIG_REALM}
Kerberos 5 realm name
Authen::Krb5::Admin::Key
This class represents key data contained in kadmin principal objects. The only methods in this class are the constructor (new, described above) and the following accessor methods.
key_contents
Key contents, encrypted with the KDC master key. This data may not be available remotely.
enc_type
Kerberos 5 enctype of the key
key_type
Alias for enc_type
kvno
Key version number
salt_contents
Salt contents, if any (ver > 1)
salt_type
Salt type, if any (ver > 1)
ver
Version number of the underlying krb5_key_data structure
Authen::Krb5::Admin::Policy
This class represents kadmin policies. The only methods in this class are the constructor (new, described above) and the following accessor methods.
mask
Mask (described above)
name {KADM5_POLICY}
Policy name
pw_history_num {KADM5_PW_HISTORY_NUM}
Number (between 1 and 10, inclusive) of past passwords to be stored for the principal. A principal may not set its password to any of its previous pw_history_num passwords.
pw_max_life {KADM5_PW_MAX_LIFE}
Default number of seconds a password lasts before the principal is required to change it
pw_max_fail {KADM5_PW_MAX_FAILURE}
The maximum allowed number of attempts before a lockout.
pw_failcnt_interval {KADM5_PW_FAILURE_COUNT_INTERVAL}
The period after which the bad preauthentication count will be reset.
pw_lockout_duration {KADM5_PW_LOCKOUT_DURATION}
The period in which lockout is enforced; a duration of zero means that the principal must be manually unlocked.
pw_min_classes {KADM5_PW_MIN_CLASSES}
Number (between 1 and 5, inclusive) of required character classes represented in a password
pw_min_length {KADM5_PW_MIN_LENGTH}
Minimum number of characters in a password
pw_min_life {KADM5_PW_MIN_LIFE}
Number of seconds a password must age before the principal may change it
policy_refcnt {KADM5_REF_COUNT}
Number of principals referring to this policy (read-only, does not set KADM5_REF_COUNT automatically)
Authen::Krb5::Admin::Principal
The attributes fail_auth_count, last_failed, and last_success are only meaningful if the KDC is configured to update the database with this type of information.

The only methods in this class are the constructor (new, described above), the following accessor methods, and policy_clear, which is used to clear the policy attribute.

attributes {KADM5_ATTRIBUTES}
Bitfield representing principal attributes (see kadmin(8))
aux_attributes {KADM5_AUX_ATTRIBUTES}
Bitfield used by kadmin. Currently only recognizes the KADM5_POLICY, which indicates that a policy is in effect for this principal. This attribute is read-only, so KADM5_AUX_ATTRIBUTES is not set automatically.
fail_auth_count {KADM5_FAIL_AUTH_COUNT}
Number of consecutive failed AS_REQs for this principal. This attribute is read-only, so KADM5_FAIL_AUTH_COUNT is not set automatically.
kvno {KADM5_KVNO}
Key version number
last_failed {KADM5_LAST_FAILED}
Time (in seconds since the Epoch) of the last failed AS_REQ for this principal. This attribute is read-only, so KADM5_LAST_FAILED is not set automatically.
last_pwd_change {KADM5_LAST_PWD_CHANGE}
Time (in seconds since the Epoch) of the last password change for this principal. This attribute is read-only, so KADM5_LAST_PWD_CHANGE is not set automatically.
last_success {KADM5_LAST_SUCCESS}
Time (in seconds since the Epoch) of the last successful AS_REQ for this principal. This attribute is read-only, so KADM5_LAST_SUCCESS is not set automatically.
mask
Mask (see above)
max_life {KADM5_MAX_LIFE}
maximum lifetime in seconds of any Kerberos ticket issued to this principal
max_renewable_life {KADM5_MAX_RLIFE}
maximum renewable lifetime in seconds of any Kerberos ticket issued to this principal
mod_date {KADM5_MOD_TIME}
Time (in seconds since the Epoch) this principal was last modified. This attribute is read-only, so KADM5_MOD_TIME is not set automatically.
mod_name {KADM5_MOD_NAME}
Kerberos principal (Authen::Krb5::Principal, see Authen::Krb5(3)) that last modified this principal. This attribute is read-only, so KADM5_MOD_NAME is not set automatically.
policy {KADM5_POLICY}
Name of policy that affects this principal if KADM5_POLICY is set in aux_attributes
policy_clear {KADM5_POLICY_CLR}
Not really an attribute---disables the current policy for this principal. This method doesn't return anything.
princ_expire_time {KADM5_PRINC_EXPIRE_TIME}
Expire time (in seconds since the Epoch) of the principal
principal {KADM5_PRINCIPAL}
Kerberos principal itself (Authen::Krb5::Principal, see Authen::Krb5(3))
pw_expiration {KADM5_PW_EXPIRATION}
Expire time (in seconds since the Epoch) of the principal's password
db_args [@ARGS]
When called without any @ARGS, returns the list of arguments that will be passed into the underlying database, as with "addprinc -x" in "kadmin". If @ARGS is non-empty, it will replace any database arguments, which will then be returned, like this:

    my @old = $principal->db_args;
    # -or-
    my @old = $principal->db_args(@new);
    # The RPC call will ignore the tail data unless
    # you set this flag:
    $principal->mask($principal->mask | KADM5_TL_DATA);

Operations

To perform kadmin operations (addprinc, delprinc, etc.), we first construct an object of the class Authen::Krb5::Admin, which contains a server handle. Then we use object methods to perform the operations using that handle.

In the following synopses, parameter types are indicated by their names as follows:

        $error          Kerberos 5 error code
        $kadm5          Authen::Krb5::Admin
        $kadm5_config   Authen::Krb5::Admin::Config
        $kadm5_pol      Authen::Krb5::Admin::Policy
        $kadm5_princ    Authen::Krb5::Admin::Principal
        $krb5_ccache    Authen::Krb5::Ccache
        $krb5_princ     Authen::Krb5::Principal
        $success        TRUE if if the call succeeeded, undef otherwise

Everything else is an unblessed scalar value (or an array of them) inferable from context.

Parameters surrounded by square brackets ([]s) are each optional.

Constructors
Each of the following constructors authenticates as $client to the admin server $service, which defaults to KADM5_ADMIN_SERVICE if undef. An undefined value for $kadm5_config will cause the interface to infer the configuration from the Kerberos 5 profile (/etc/krb5.conf by default).
$kadm5 = Authen::Krb5::Admin->init_with_creds($client, $krb5_ccache[, $service, $kadm5_config])
Authenticate using the credentials cached in $krb5_ccache.
$kadm5 = Authen::Krb5::Admin->init_with_password($client[, $password, $service, $kadm5_config])
Authenticate with $password.
$kadm5 = Authen::Krb5::Admin->init_with_skey($client[, $keytab_file, $service, $kadm5_config])
Authenticate using the keytab stored in $keytab_file. If $keytab_file is undef, the default keytab is used.
Principal Operations
$success = $kadm5->chpass_principal($krb5_princ, $password)
Change the password of $krb5_princ to $password.
$success = $kadm5->create_principal($kadm5_princ[, $password])
Insert $kadm5_princ into the database, optionally setting its password to the string in $password. Clears KADM5_POLICY_CLR and KADM5_FAIL_AUTH_COUNT.
$success = $kadm5->delete_principal($krb5_princ)
Delete the principal represented by $krb5_princ from the database.
$kadm5_princ = $kadm5->get_principal($krb5_princ[, $mask])
Retrieve the Authen::Krb5::Admin::Principal object for the principal $krb5_princ from the database. Use KADM5_PRINCIPAL_NORMAL_MASK to retrieve all of the useful attributes.
@names = $kadm5->get_principals([$expr])
Retrieve a list of principal names matching the glob pattern $expr. In the absence of $expr, retrieve the list of all principal names.
$success = $kadm5->modify_principal($kadm5_princ)
Modify $kadm5_princ in the database. The principal to modify is determined by "$kadm5_princ->principal", and the rest of the writable parameters will be modified accordingly. Clears KADM5_PRINCIPAL.
@keys = $kadm5->randkey_principal($krb5_princ)
Randomize the principal in the database represented by $krb5_princ and return Authen::Krb5::Keyblock objects.
$success = $kadm5->rename_principal($krb5_princ_from, $krb5_princ_to)
Change the name of the principal from $krb5_princ_from to $krb5_princ_to.
Policy Operations
$success = $kadm5->create_policy($kadm5_pol)
Insert $kadm5_pol into the database.
$success = $kadm5->delete_policy($name)
Delete the policy named $name from the database.
$kadm5_pol = $kadm5->get_policy([$name])
Retrieve the Authen::Krb5::Admin::Policy object for the policy named $name from the database.
@names = $kadm5->get_policies([$expr])
Retrieve a list of policy names matching the glob pattern $expr. In the absence of $expr, retrieve the list of all policy names.
$success = $kadm5->modify_policy($kadm5_pol)
Modify $kadm5_pol in the database. The policy to modify is determined by "$kadm5_pol-"name>,(and the rest of the writable) parameters will be modified accordingly. Clears KADM5_POLICY.
Other Methods
$magic_value = Authen::Krb5::Admin::error [$error]
Return value that acts like $! (see perlvar(1)) for the most recent Authen::Krb5::Admin call. With error code $error, return the error message corresponding to that error code.
$error_code = Authen::Krb5::Admin::error_code
Returns the value of the error code for the most recent Authen::Krb5::Admin call as a simple integer.
$privs = $kadm5->get_privs
Return a bitfield representing the kadmin privileges a principal has, as follows:

        get     KADM5_PRIV_GET
        add     KADM5_PRIV_ADD
        modify  KADM5_PRIV_MODIFY
        delete  KADM5_PRIV_DELETE

EXAMPLES

See the unit tests included with this software for examlpes. They can be found in the t/ subdirectory of the distribution.

FILES

 krb.conf               Kerberos 5 configuration file

BUGS

There is no facility for specifying keysalts for methods like create_principal and modify_principal. This facility is provided by the Kerberos 5 API and requires an initialized context. So it probably makes more sense for Authen::Krb5(3) to handle those functions.

AUTHOR

Stephen Quinney <squi[email protected]>

Author Emeritus: Andrew J. Korty <[email protected]>