SLAPO_PPOLICY(5)SLAPO_PPOLICY(5)NAMEslapo-ppolicy - Password Policy overlay to slapd
SYNOPSIS
/etc/openldap/slapd.conf
DESCRIPTION
The ppolicy overlay is an implementation of the most recent IETF Pass‐
word Policy proposal for LDAP. When instantiated, it intercepts,
decodes and applies specific password policy controls to overall use of
a backend database, changes to user password fields, etc.
The overlay provides a variety of password control mechanisms. They
include password aging -- both minimum and maximum ages, password reuse
and duplication control, account time-outs, mandatory password resets,
acceptable password content, and even grace logins. Different groups
of users may be associated with different password policies, and there
is no limit to the number of password policies that may be created.
Note that some of the policies do not take effect when the operation is
performed with the rootdn identity; all the operations, when performed
with any other identity, may be subjected to constraints, like access
control.
Note that the IETF Password Policy proposal for LDAP makes sense when
considering a single-valued password attribute, while the userPassword
attribute allows multiple values. This implementation enforces a sin‐
gle value for the userPassword attribute, despite its specification.
CONFIGURATION
These slapd.conf configuration options apply to the ppolicy overlay.
They should appear after the overlay directive.
ppolicy_default <policyDN>
Specify the DN of the pwdPolicy object to use when no specific
policy is set on a given user's entry. If there is no specific
policy for an entry and no default is given, then no policies
will be enforced.
ppolicy_forward_updates
Specify that policy state changes that result from Bind opera‐
tions (such as recording failures, lockout, etc.) on a consumer
should be forwarded to a master instead of being written
directly into the consumer's local database. This setting is
only useful on a replication consumer, and also requires the
updateref setting and chain overlay to be appropriately config‐
ured.
ppolicy_hash_cleartext
Specify that cleartext passwords present in Add and Modify
requests should be hashed before being stored in the database.
This violates the X.500/LDAP information model, but may be
needed to compensate for LDAP clients that don't use the Pass‐
word Modify extended operation to manage passwords. It is rec‐
ommended that when this option is used that compare, search, and
read access be denied to all directory users.
ppolicy_use_lockout
A client will always receive an LDAP InvalidCredentials response
when Binding to a locked account. By default, when a Password
Policy control was provided on the Bind request, a Password Pol‐
icy response will be included with no special error code set.
This option changes the Password Policy response to include the
AccountLocked error code. Note that sending the AccountLocked
error code provides useful information to an attacker; sites
that are sensitive to security issues should not enable this
option.
OBJECT CLASS
The ppolicy overlay depends on the pwdPolicy object class. The defini‐
tion of that class is as follows:
( 1.3.6.1.4.1.42.2.27.8.2.1
NAME 'pwdPolicy'
AUXILIARY
SUP top
MUST ( pwdAttribute )
MAY (
pwdMinAge $ pwdMaxAge $ pwdInHistory $
pwdCheckQuality $ pwdMinLength $
pwdExpireWarning $ pwdGraceAuthnLimit $
pwdLockout $ pwdLockoutDuration $
pwdMaxFailure $ pwdFailureCountInterval $
pwdMustChange $ pwdAllowUserChange $
pwdSafeModify ) )
This implementation also provides an additional pwdPolicyChecker
objectclass, used for password quality checking (see below).
( 1.3.6.1.4.1.4754.2.99.1
NAME 'pwdPolicyChecker'
AUXILIARY
SUP top
MAY ( pwdCheckModule ) )
Every account that should be subject to password policy control should
have a pwdPolicySubentry attribute containing the DN of a valid pwdPol‐
icy entry, or they can simply use the configured default. In this way
different users may be managed according to different policies.
OBJECT CLASS ATTRIBUTES
Each one of the sections below details the meaning and use of a partic‐
ular attribute of this pwdPolicy object class.
pwdAttribute
This attribute contains the name of the attribute to which the password
policy is applied. For example, the password policy may be applied to
the userPassword attribute.
Note: in this implementation, the only value accepted for pwdAttribute
is userPassword .
( 1.3.6.1.4.1.42.2.27.8.1.1
NAME 'pwdAttribute'
EQUALITY objectIdentifierMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )
pwdMinAge
This attribute contains the number of seconds that must elapse between
modifications allowed to the password. If this attribute is not
present, zero seconds is assumed (i.e. the password may be modified
whenever and however often is desired).
( 1.3.6.1.4.1.42.2.27.8.1.2
NAME 'pwdMinAge'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdMaxAge
This attribute contains the number of seconds after which a modified
password will expire. If this attribute is not present, or if its
value is zero (0), then passwords will not expire.
( 1.3.6.1.4.1.42.2.27.8.1.3
NAME 'pwdMaxAge'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdInHistory
This attribute is used to specify the maximum number of used passwords
that will be stored in the pwdHistory attribute. If the pwdInHistory
attribute is not present, or if its value is zero (0), used passwords
will not be stored in pwdHistory and thus any previously-used password
may be reused. No history checking occurs if the password is being
modified by the rootdn, although the password is saved in the history.
( 1.3.6.1.4.1.42.2.27.8.1.4
NAME 'pwdInHistory'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdCheckQuality
This attribute indicates if and how password syntax will be checked
while a password is being modified or added. If this attribute is not
present, or its value is zero (0), no syntax checking will be done. If
its value is one (1), the server will check the syntax, and if the
server is unable to check the syntax, whether due to a client-side
hashed password or some other reason, it will be accepted. If its value
is two (2), the server will check the syntax, and if the server is
unable to check the syntax it will return an error refusing the pass‐
word.
( 1.3.6.1.4.1.42.2.27.8.1.5
NAME 'pwdCheckQuality'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdMinLength
When syntax checking is enabled (see also the pwdCheckQuality
attribute), this attribute contains the minimum number of characters
that will be accepted in a password. If this attribute is not present,
minimum password length is not enforced. If the server is unable to
check the length of the password, whether due to a client-side hashed
password or some other reason, the server will, depending on the value
of pwdCheckQuality, either accept the password without checking it (if
pwdCheckQuality is zero (0) or one (1)) or refuse it (if pwdCheckQual‐
ity is two (2)).
( 1.3.6.1.4.1.42.2.27.8.1.6
NAME 'pwdMinLength'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdExpireWarning
This attribute contains the maximum number of seconds before a password
is due to expire that expiration warning messages will be returned to a
user who is authenticating to the directory. If this attribute is not
present, or if the value is zero (0), no warnings will be sent.
( 1.3.6.1.4.1.42.2.27.8.1.7
NAME 'pwdExpireWarning'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdGraceAuthnLimit
This attribute contains the number of times that an expired password
may be used to authenticate a user to the directory. If this attribute
is not present or if its value is zero (0), users with expired pass‐
words will not be allowed to authenticate to the directory.
( 1.3.6.1.4.1.42.2.27.8.1.8
NAME 'pwdGraceAuthnLimit'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdLockout
This attribute specifies the action that should be taken by the direc‐
tory when a user has made a number of failed attempts to authenticate
to the directory. If pwdLockout is set (its value is "TRUE"), the user
will not be allowed to attempt to authenticate to the directory after
there have been a specified number of consecutive failed bind attempts.
The maximum number of consecutive failed bind attempts allowed is spec‐
ified by the pwdMaxFailure attribute. If pwdLockout is not present, or
if its value is "FALSE", the password may be used to authenticate no
matter how many consecutive failed bind attempts have been made.
( 1.3.6.1.4.1.42.2.27.8.1.9
NAME 'pwdLockout'
EQUALITY booleanMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
SINGLE-VALUE )
pwdLockoutDuration
This attribute contains the number of seconds during which the password
cannot be used to authenticate the user to the directory due to too
many consecutive failed bind attempts. (See also pwdLockout and pwd‐
MaxFailure.) If pwdLockoutDuration is not present, or if its value is
zero (0), the password cannot be used to authenticate the user to the
directory again until it is reset by an administrator.
( 1.3.6.1.4.1.42.2.27.8.1.10
NAME 'pwdLockoutDuration'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdMaxFailure
This attribute contains the number of consecutive failed bind attempts
after which the password may not be used to authenticate a user to the
directory. If pwdMaxFailure is not present, or its value is zero (0),
then a user will be allowed to continue to attempt to authenticate to
the directory, no matter how many consecutive failed bind attempts have
occurred with that user's DN. (See also pwdLockout and pwdLockoutDura‐
tion.)
( 1.3.6.1.4.1.42.2.27.8.1.11
NAME 'pwdMaxFailure'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdFailureCountInterval
This attribute contains the number of seconds after which old consecu‐
tive failed bind attempts are purged from the failure counter, even
though no successful authentication has occurred. If pwdFailure‐
CountInterval is not present, or its value is zero (0), the failure
counter will only be reset by a successful authentication.
( 1.3.6.1.4.1.42.2.27.8.1.12
NAME 'pwdFailureCountInterval'
EQUALITY integerMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27
SINGLE-VALUE )
pwdMustChange
This attribute specifies whether users must change their passwords when
they first bind to the directory after a password is set or reset by
the administrator, or not. If pwdMustChange has a value of "TRUE",
users must change their passwords when they first bind to the directory
after a password is set or reset by the administrator. If pwd‐
MustChange is not present, or its value is "FALSE", users are not
required to change their password upon binding after the administrator
sets or resets the password.
( 1.3.6.1.4.1.42.2.27.8.1.13
NAME 'pwdMustChange'
EQUALITY booleanMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
SINGLE-VALUE )
pwdAllowUserChange
This attribute specifies whether users are allowed to change their own
passwords or not. If pwdAllowUserChange is set to "TRUE", or if the
attribute is not present, users will be allowed to change their own
passwords. If its value is "FALSE", users will not be allowed to
change their own passwords.
( 1.3.6.1.4.1.42.2.27.8.1.14
NAME 'pwdAllowUserChange'
EQUALITY booleanMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
SINGLE-VALUE )
pwdSafeModify
This attribute denotes whether the user's existing password must be
sent along with their new password when changing a password. If pwd‐
SafeModify is set to "TRUE", the existing password must be sent along
with the new password. If the attribute is not present, or its value
is "FALSE", the existing password need not be sent along with the new
password.
( 1.3.6.1.4.1.42.2.27.8.1.15
NAME 'pwdSafeModify'
EQUALITY booleanMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
SINGLE-VALUE )
pwdCheckModule
This attribute names a user-defined loadable module that must instanti‐
ate the check_password() function. This function will be called to
further check a new password if pwdCheckQuality is set to one (1) or
two (2), after all of the built-in password compliance checks have been
passed. This function will be called according to this function proto‐
type:
int check_password (char *pPasswd, char **ppErrStr, Entry *pEntry);
The pPasswd parameter contains the clear-text user password, the
ppErrStr parameter contains a double pointer that allows the function
to return human-readable details about any error it encounters. The
optional pEntry parameter, if non-NULL, carries a pointer to the entry
whose password is being checked. If ppErrStr is NULL, then funcName
must NOT attempt to use it/them. A return value of LDAP_SUCCESS from
the called function indicates that the password is ok, any other value
indicates that the password is unacceptable. If the password is unac‐
ceptable, the server will return an error to the client, and ppErrStr
may be used to return a human-readable textual explanation of the
error. The error string must be dynamically allocated as it will be
free()'d by slapd.
( 1.3.6.1.4.1.4754.1.99.1
NAME 'pwdCheckModule'
EQUALITY caseExactIA5Match
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26
SINGLE-VALUE )
Note: The user-defined loadable module named by pwdCheckModule must be
in slapd's standard executable search PATH.
Note: pwdCheckModule is a non-standard extension to the LDAP password
policy proposal.
OPERATIONAL ATTRIBUTES
The operational attributes used by the ppolicy module are stored in the
user's entry. Most of these attributes are not intended to be changed
directly by users; they are there to track user activity. They have
been detailed here so that administrators and users can both understand
the workings of the ppolicy module.
Note that the current IETF Password Policy proposal does not define how
these operational attributes are expected to behave in a replication
environment. In general, authentication attempts on a slave server only
affect the copy of the operational attributes on that slave and will
not affect any attributes for a user's entry on the master server.
Operational attribute changes resulting from authentication attempts on
a master server will usually replicate to the slaves (and also over‐
write any changes that originated on the slave). These behaviors are
not guaranteed and are subject to change when a formal specification
emerges.
userPassword
The userPassword attribute is not strictly part of the ppolicy module.
It is, however, the attribute that is tracked and controlled by the
module. Please refer to the standard OpenLDAP schema for its defini‐
tion.
pwdPolicySubentry
This attribute refers directly to the pwdPolicy subentry that is to be
used for this particular directory user. If pwdPolicySubentry exists,
it must contain the DN of a valid pwdPolicy object. If it does not
exist, the ppolicy module will enforce the default password policy
rules on the user associated with this authenticating DN. If there is
no default, or the referenced subentry does not exist, then no policy
rules will be enforced.
( 1.3.6.1.4.1.42.2.27.8.1.23
NAME 'pwdPolicySubentry'
DESC 'The pwdPolicy subentry in effect for
this object'
EQUALITY distinguishedNameMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
SINGLE-VALUE
NO-USER-MODIFICATION
USAGE directoryOperation)
pwdChangedTime
This attribute denotes the last time that the entry's password was
changed. This value is used by the password expiration policy to
determine whether the password is too old to be allowed to be used for
user authentication. If pwdChangedTime does not exist, the user's
password will not expire.
( 1.3.6.1.4.1.42.2.27.8.1.16
NAME 'pwdChangedTime'
DESC 'The time the password was last changed'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
EQUALITY generalizedTimeMatch
ORDERING generalizedTimeOrderingMatch
SINGLE-VALUE
NO-USER-MODIFICATION
USAGE directoryOperation)
pwdAccountLockedTime
This attribute contains the time that the user's account was locked.
If the account has been locked, the password may no longer be used to
authenticate the user to the directory. If pwdAccountLockedTime is set
to 000001010000Z, the user's account has been permanently locked and
may only be unlocked by an administrator. Note that account locking
only takes effect when the pwdLockout password policy attribute is set
to "TRUE".
( 1.3.6.1.4.1.42.2.27.8.1.17
NAME 'pwdAccountLockedTime'
DESC 'The time an user account was locked'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
EQUALITY generalizedTimeMatch
ORDERING generalizedTimeOrderingMatch
SINGLE-VALUE
NO-USER-MODIFICATION
USAGE directoryOperation)
pwdFailureTime
This attribute contains the timestamps of each of the consecutive
authentication failures made upon attempted authentication to this DN
(i.e. account). If too many timestamps accumulate here (refer to the
pwdMaxFailure password policy attribute for details), and the pwdLock‐
out password policy attribute is set to "TRUE", the account may be
locked. (Please also refer to the pwdLockout password policy
attribute.) Excess timestamps beyond those allowed by pwdMaxFailure
may also be purged. If a successful authentication is made to this DN
(i.e. to this user account), then pwdFailureTime will be cleansed of
entries.
( 1.3.6.1.4.1.42.2.27.8.1.19
NAME 'pwdFailureTime'
DESC 'The timestamps of the last consecutive
authentication failures'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
EQUALITY generalizedTimeMatch
ORDERING generalizedTimeOrderingMatch
NO-USER-MODIFICATION
USAGE directoryOperation )
pwdHistory
This attribute contains the history of previously used passwords for
this DN (i.e. for this user account). The values of this attribute are
stored in string format as follows:
pwdHistory=
time "#" syntaxOID "#" length "#" data
time=
GeneralizedTime as specified in section 3.3.13 of [RFC4517]
syntaxOID = numericoid
This is the string representation of the dotted-decimal OID
that defines the syntax used to store the password. numericoid
is described in section 1.4 of [RFC4512].
length = NumericString
The number of octets in the data. NumericString is described
in section 3.3.23 of [RFC4517].
data =
Octets representing the password in the format specified by
syntaxOID.
This format allows the server to store and transmit a history of pass‐
words that have been used. In order for equality matching on the val‐
ues in this attribute to function properly, the time field is in GMT
format.
( 1.3.6.1.4.1.42.2.27.8.1.20
NAME 'pwdHistory'
DESC 'The history of user passwords'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.40
EQUALITY octetStringMatch
NO-USER-MODIFICATION
USAGE directoryOperation)
pwdGraceUseTime This attribute contains the list of timestamps of
logins made after the user password in the DN has expired. These post-
expiration logins are known as "grace logins". If too many grace
logins have been used (please refer to the pwdGraceLoginLimit password
policy attribute), then the DN will no longer be allowed to be used to
authenticate the user to the directory until the administrator changes
the DN's userPassword attribute.
( 1.3.6.1.4.1.42.2.27.8.1.21
NAME 'pwdGraceUseTime'
DESC 'The timestamps of the grace login once the password has
expired'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
EQUALITY generalizedTimeMatch
NO-USER-MODIFICATION
USAGE directoryOperation)
pwdReset
This attribute indicates whether the user's password has been reset by
the administrator and thus must be changed upon first use of this DN
for authentication to the directory. If pwdReset is set to "TRUE",
then the password was reset and the user must change it upon first
authentication. If the attribute does not exist, or is set to "FALSE",
the user need not change their password due to administrative reset.
( 1.3.6.1.4.1.42.2.27.8.1.22
NAME 'pwdReset'
DESC 'The indication that the password has
been reset'
EQUALITY booleanMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.7
SINGLE-VALUE
USAGE directoryOperation)
EXAMPLES
database bdb
suffix dc=example,dc=com
...
overlay ppolicy
ppolicy_default "cn=Standard,ou=Policies,dc=example,dc=com"
SEE ALSOldap(3), slapd.conf(5), slapd-config(5), slapo-chain(5).
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
IETF LDAP password policy proposal by P. Behera, L. Poitou and J.
Sermersheim: documented in IETF document "draft-behera-ldap-password-
policy-09.txt".
BUGS
The LDAP Password Policy specification is not yet an approved standard,
and it is still evolving. This code will continue to be in flux until
the specification is finalized.
ACKNOWLEDGEMENTS
This module was written in 2004 by Howard Chu of Symas Corporation with
significant input from Neil Dunbar and Kartik Subbarao of Hewlett-
Packard.
This manual page borrows heavily and shamelessly from the specification
upon which the password policy module it describes is based. This
source is the IETF LDAP password policy proposal by P. Behera, L.
Poitou and J. Sermersheim. The proposal is fully documented in the
IETF document named draft-behera-ldap-password-policy-09.txt, written
in July of 2005.
OpenLDAP Software is developed and maintained by The OpenLDAP Project
<http://www.openldap.org/>. OpenLDAP Software is derived from Univer‐
sity of Michigan LDAP 3.3 Release.
OpenLDAP 2.4.23 2010/06/30 SLAPO_PPOLICY(5)
