openldap/doc/man/man5/slapo-ppolicy.5

.TH SLAPO_PPOLICY 5 "RELEASEDATE" "OpenLDAP LDVERSION"
.\" Copyright 2004-2012 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
.\" $OpenLDAP$
.SH NAME
slapo\-ppolicy \- Password Policy overlay to slapd
.SH SYNOPSIS
ETCDIR/slapd.conf
.SH DESCRIPTION
.LP
The 
.B ppolicy
overlay
is an implementation of the most recent IETF Password
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.
.P
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.
.P
Note that some of the policies do not take effect when the operation
is performed with the
.B rootdn
identity; all the operations, when performed with any other identity,
may be subjected to constraints, like access control.
.P
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 single value for the userPassword attribute, despite
its specification.

.SH CONFIGURATION
These 
.B slapd.conf
configuration options apply to the ppolicy overlay. They should appear
after the
.B overlay
directive.
.TP
.B 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.
.TP
.B ppolicy_forward_updates
Specify that policy state changes that result from Bind operations (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
.B updateref
setting and
.B chain
overlay to be appropriately configured.
.TP
.B 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 Password Modify extended operation to manage passwords.  It
is recommended that when this option is used that compare, search, and
read access be denied to all directory users. 
.TP
.B ppolicy_use_lockout
A client will always receive an LDAP
.B InvalidCredentials
response when
Binding to a locked account. By default, when a Password Policy control
was provided on the Bind request, a Password Policy response will be
included with no special error code set. This option changes the
Password Policy response to include the
.B AccountLocked
error code. Note
that sending the
.B AccountLocked
error code provides useful information
to an attacker; sites that are sensitive to security issues should not
enable this option.

.SH OBJECT CLASS
The 
.B ppolicy
overlay depends on the
.B pwdPolicy
object class.  The definition of that class is as follows:
.LP
.RS 4
(  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 ) )
.RE

This implementation also provides an additional
.B pwdPolicyChecker
objectclass, used for password quality checking (see below).
.LP
.RS 4
(  1.3.6.1.4.1.4754.2.99.1
    NAME 'pwdPolicyChecker'
    AUXILIARY
    SUP top
    MAY ( pwdCheckModule ) )
.RE
.P
Every account that should be subject to password policy control should
have a
.B
pwdPolicySubentry
attribute containing the DN of a valid
.B pwdPolicy
entry, or they can simply use the configured default.
In this way different users may be managed according to
different policies.

.SH OBJECT CLASS ATTRIBUTES
.P
Each one of the sections below details the meaning and use of a particular
attribute of this
.B pwdPolicy
object class.
.P

.B pwdAttribute
.P
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
.B userPassword
attribute.
.P
Note: in this implementation, the only
value accepted for
.B pwdAttribute
is
.IR " userPassword ".
.LP
.RS 4
(  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 )
.RE

.B pwdMinAge
.P
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).
.LP
.RS 4
(  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 )
.RE

.B pwdMaxAge
.P
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.
.LP
.RS 4
(  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 )
.RE

.B pwdInHistory
.P
This attribute is used to specify the maximum number of used
passwords that will be stored in the
.B pwdHistory
attribute.  If the
.B pwdInHistory
attribute is not present, or if its value is
zero (0), used passwords will not be stored in
.B pwdHistory
and thus any previously-used password may be reused.
No history checking occurs if the password is being modified by the
.BR rootdn ,
although the password is saved in the history.
.LP
.RS 4
(  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 )
.RE

.B pwdCheckQuality
.P
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 password.
.LP
.RS 4
(  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 )
.RE

.B pwdMinLength
.P
When syntax checking is enabled
(see also the
.B 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
.BR pwdCheckQuality ,
either accept the password
without checking it (if
.B pwdCheckQuality
is zero (0) or one (1)) or refuse it (if
.B pwdCheckQuality
is two (2)).
.LP
.RS 4
(  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 )
.RE

.B pwdExpireWarning
.P
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.
.LP
.RS 4
(  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 )
.RE

.B pwdGraceAuthnLimit
.P
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 passwords will not be allowed to authenticate to the
directory.
.LP
.RS 4
(  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 )
.RE

.B pwdLockout
.P
This attribute specifies the action that should be taken
by the directory when a user has made a number of failed attempts
to authenticate to the directory.  If
.B 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 specified by
the
.B pwdMaxFailure
attribute.  If
.B 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.
.LP
.RS 4
(  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 )
.RE

.B pwdLockoutDuration
.P
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
.B pwdLockout
and
.BR pwdMaxFailure .)
If
.B 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.
.LP
.RS 4
(  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 )
.RE

.B pwdMaxFailure
.P
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
.B 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
.B pwdLockout
and
.BR pwdLockoutDuration .)
.LP
.RS 4
(  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 )
.RE

.B pwdFailureCountInterval
.P
This attribute contains the number of seconds after which old
consecutive failed bind attempts are purged from the failure counter,
even though no successful authentication has occurred.
If
.B pwdFailureCountInterval
is not present, or its value is zero (0), the failure
counter will only be reset by a successful authentication.
.LP
.RS 4
(  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 )
.RE

.B pwdMustChange
.P
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
.B 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
.B pwdMustChange
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.
.LP
.RS 4
(  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 )
.RE

.B pwdAllowUserChange
.P
This attribute specifies whether users are allowed to change their own
passwords or not.  If
.B 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.
.LP
Note: this implies that when
.B pwdAllowUserChange
is set to "TRUE",
users will still be able to change the password of another user,
subjected to access control.
This restriction only applies to modifications of ones's own password.
It should also be noted that
.B pwdAllowUserChange
was defined in the specification to provide rough access control
to the password attribute in implementations that do not allow fine-grain
access control.
Since OpenLDAP provides fine-grain access control, the use of this attribute
is discouraged; ACLs should be used instead
(see
.BR slapd.access (5)
for details).
.LP
.RS 4
(  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 )
.RE

.B pwdSafeModify
.P
This attribute denotes whether the user's existing password must be sent
along with their new password when changing a password.  If
.B pwdSafeModify
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.
.LP
.RS 4
(  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 )
.RE

.B pwdCheckModule
.P
This attribute names a user-defined loadable module that must
instantiate the check_password() function.  This function
will be called to further check a new password if
.B 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 prototype:
.RS 4
int
.I check_password
(char *pPasswd, char **ppErrStr, Entry *pEntry);
.RE
The
.B pPasswd
parameter contains the clear-text user password, the
.B ppErrStr
parameter contains a double pointer that allows the function
to return human-readable details about any error it encounters.
The optional
.B pEntry
parameter, if non-NULL, carries a pointer to the
entry whose password is being checked.
If
.B ppErrStr
is NULL, then 
.I 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
unacceptable, the server will return an error to the client, and
.B 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.
.LP
.RS 4
(  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 )
.RE
.P
Note: 
The user-defined loadable module named by
.B pwdCheckModule     
must be in
.B slapd's
standard executable search PATH.
.P
Note:
.B pwdCheckModule
is a non-standard extension to the LDAP password
policy proposal.

.SH OPERATIONAL ATTRIBUTES
.P
The operational attributes used by the
.B 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
.B ppolicy
module.

.P
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 overwrite
any changes that originated on the slave). 
These behaviors are not guaranteed and are subject to change
when a formal specification emerges.

.B userPassword
.P
The
.B userPassword
attribute is not strictly part of the
.B ppolicy
module.  It is, however, the attribute that is tracked and controlled
by the module.  Please refer to the standard OpenLDAP schema for
its definition.

.B pwdPolicySubentry
.P
This attribute refers directly to the
.B pwdPolicy
subentry that is to be used for this particular directory user.
If
.B pwdPolicySubentry
exists, it must contain the DN of a valid
.B pwdPolicy
object.  If it does not exist, the
.B 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.
.LP
.RS 4
(  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)
.RE

.B pwdChangedTime
.P
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
.B pwdChangedTime
does not exist, the user's password will not expire.
.LP
.RS 4
(  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)
.RE

.B pwdAccountLockedTime
.P
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
.B 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
.B pwdLockout
password policy attribute is set to "TRUE".
.LP
.RS 4
(  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)
.RE

.B pwdFailureTime
.P
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
.B pwdMaxFailure
password policy attribute for details),
and the
.B pwdLockout
password policy attribute is set to "TRUE", the
account may be locked.
(Please also refer to the
.B pwdLockout
password policy attribute.)
Excess timestamps beyond those allowed by
.B pwdMaxFailure
may also be purged.  If a successful authentication is made to this
DN (i.e. to this user account), then
.B pwdFailureTime   
will be cleansed of entries.
.LP
.RS 4
(  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 )
.RE

.B pwdHistory
.P
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:

.RS 4

pwdHistory=
.RS 4
time "#" syntaxOID "#" length "#" data
.RE

time=
.RS 4
GeneralizedTime as specified in section 3.3.13 of [RFC4517]
.RE

.P
syntaxOID = numericoid
.RS 4
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].
.RE

length = NumericString
.RS 4
The number of octets in the data.  NumericString is described in
section 3.3.23 of [RFC4517].
.RE

data =
.RS 4
Octets representing the password in the format specified by syntaxOID.
.RE

.RE

This format allows the server to store and transmit a history of
passwords that have been used.  In order for equality matching
on the values in this attribute to function properly, the time
field is in GMT format.
.LP
.RS 4
(  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)
.RE

.B 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 "\fIgrace logins\fP".
If too many
.I grace logins
have been used (please refer to the
.B 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
.B userPassword
attribute.
.LP
.RS 4
(  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)
.RE

.B pwdReset
.P
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
.B 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.
.LP
.RS 4
(  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)
.RE

.SH EXAMPLES
.LP
.RS
.nf
database bdb
suffix dc=example,dc=com
\|...
overlay ppolicy
ppolicy_default "cn=Standard,ou=Policies,dc=example,dc=com"
.fi
.RE

.SH SEE ALSO
.BR ldap (3),
.BR slapd.conf (5),
.BR slapd\-config (5),
.BR slapo\-chain (5).
.LP
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
.LP
IETF LDAP password policy proposal by P. Behera, L.  Poitou and J.
Sermersheim:  documented in IETF document
"draft-behera-ldap-password-policy-09.txt".

.SH 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.

.SH ACKNOWLEDGEMENTS
.P
This module was written in 2004 by Howard Chu of Symas Corporation
with significant input from Neil Dunbar and Kartik Subbarao of Hewlett-Packard.
.P
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.
.P
.so ../Project