Ubuntu Manpage: nslcd.conf - configuration file for LDAP nameservice daemon

Provided by: nslcd_0.8.13-3ubuntu1_amd64

NAME

       nslcd.conf - configuration file for LDAP nameservice daemon

DESCRIPTION

       The  nss-pam-ldapd package allows LDAP directory servers to be used as a primary source of
       name service information. (Name  service  information  typically  includes  users,  hosts,
       groups, and other such data historically stored in flat files or NIS.)

       The  file  nslcd.conf  contains  the  configuration  information  for  running  nslcd (see
       nslcd(8)).  The file contains options, one on each line, defining the way NSS lookups  and
       PAM actions are mapped to LDAP lookups.

OPTIONS

RUNTIME OPTIONS
threads NUM
Specifies the number of threads to start that can handle requests and perform LDAP
queries. Each thread opens a separate connection to the LDAP server. The default
is to start 5 threads.

uid UID
This specifies the user id with which the daemon should be run. This can be a
numerical id or a symbolic value. If no uid is specified no attempt to change the
user will be made. Note that you should use values that don't need LDAP to
resolve.

gid GID
This specifies the group id with which the daemon should be run. This can be a
numerical id or a symbolic value. If no gid is specified no attempt to change the
group will be made. Note that you should use values that don't need LDAP to
resolve.

GENERAL CONNECTION OPTIONS
uri URI
Specifies the LDAP URI of the server to connect to. The URI scheme may be ldap,
ldapi or ldaps, specifying LDAP over TCP, ICP or SSL respectively (if supported by
the LDAP library).

Alternatively, the value DNS may be used to try to lookup the server using DNS SRV
records. By default the current domain is used but another domain can be queried
by using the DNS:DOMAIN syntax.

When using the ldapi scheme, %2f should be used to escape slashes (e.g.
ldapi://%2fvar%2frun%2fslapd%2fldapi/), although most of the time this should not
be needed.

This option may be specified multiple times. Normally, only the first server will
be used with the following servers as fall-back (see bind_timelimit below).

If LDAP lookups are used for host name resolution, any host names should be
specified as an IP address or name that can be resolved without using LDAP.

ldap_version VERSION
Specifies the version of the LDAP protocol to use. The default is to use the
maximum version supported by the LDAP library.

binddn DN
Specifies the distinguished name with which to bind to the directory server for
lookups. The default is to bind anonymously.

bindpw PASSWORD
Specifies the credentials with which to bind. This option is only applicable when
used with binddn above. If you set this option you should consider changing the
permissions of the nslcd.conf file to only grant access to the root user.

rootpwmoddn DN
Specifies the distinguished name to use when the root user tries to modify a user's
password using the PAM module.

rootpwmodpw PASSWORD
Specifies the credentials with which to bind if the root user tries to change a
user's password. This option is only applicable when used with rootpwmoddn above.
If this option is not specified the PAM module prompts the user for this password.
If you set this option you should consider changing the permissions of the
nslcd.conf file to only grant access to the root user.

SASL AUTHENTICATION OPTIONS
sasl_mech MECHANISM
Specifies the SASL mechanism to be used when performing SASL authentication.

sasl_realm REALM
Specifies the SASL realm to be used when performing SASL authentication.

sasl_authcid AUTHCID
Specifies the authentication identity to be used when performing SASL
authentication.

sasl_authzid AUTHZID
Specifies the authorization identity to be used when performing SASL
authentication. Must be specified in one of the formats: dn:<distinguished name>
or u:<username>.

sasl_secprops PROPERTIES
Specifies Cyrus SASL security properties. Allowed values are described in the
ldap.conf(5) manual page.

sasl_canonicalize yes|no
Determines whether the LDAP server host name should be canonicalised. If this is
set to yes the LDAP library will do a reverse host name lookup. By default, it is
left up to the LDAP library whether this check is performed or not.

KERBEROS AUTHENTICATION OPTIONS
krb5_ccname NAME
Set the name for the GSS-API Kerberos credentials cache.

SEARCH/MAPPING OPTIONS
base [MAP] DN
Specifies the base distinguished name (DN) to use as search base. This option may
be supplied multiple times and all specified bases will be searched.

A global search base may be specified or a MAP-specific one. If no MAP-specific
search bases are defined the global ones are used.

If, instead of a DN, the value DOMAIN is specified, the host's DNS domain is used
to construct a search base.

If this value is not defined an attempt is made to look it up in the configured
LDAP server. Note that if the LDAP server is unavailable during start-up nslcd will
not start.

scope [MAP] sub[tree]|one[level]|base
Specifies the search scope (subtree, one level or base object). The default scope
is subtree; base scope is almost never useful for name service lookups.

deref never|searching|finding|always
Specifies the policy for dereferencing aliases. The default policy is to never
dereference aliases.

referrals yes|no
Specifies whether automatic referral chasing should be enabled. The default
behaviour is to chase referrals.

filter MAP FILTER
The FILTER is an LDAP search filter to use for a specific map. The default filter
is a basic search on the objectClass for the map (e.g. (objectClass=posixAccount)).

map MAP ATTRIBUTE NEWATTRIBUTE
This option allows for custom attributes to be looked up instead of the default RFC
2307 attributes. The MAP may be one of the supported maps below. The ATTRIBUTE is
the one as used in RFC 2307 (e.g. userPassword, ipProtocolNumber, macAddress,
etc.). The NEWATTRIBUTE may be any attribute as it is available in the directory.

If the NEWATTRIBUTE is presented in quotes (") it is treated as an expression which
will be evaluated to build up the actual value used. See the section on attribute
mapping expressions below for more details.

Only some attributes for group, passwd and shadow entries may be mapped with an
expression (because other attributes may be used in search filters). For group
entries only the userPassword attribute may be mapped with an expression. For
passwd entries the following attributes may be mapped with an expression:
userPassword, gidNumber, gecos, homeDirectory and loginShell. For shadow entries
the following attributes may be mapped with an expression: userPassword,
shadowLastChange, shadowMin, shadowMax, shadowWarning, shadowInactive, shadowExpire
and shadowFlag.

The uidNumber and gidNumber attributes in the passwd and group maps may be mapped
to the objectSid followed by the domain SID to derive numeric user and group ids
from the SID (e.g. objectSid:S-1-5-21-3623811015-3361044348-30300820).

By default all userPassword attributes are mapped to the unmatchable password ("*")
to avoid accidentally leaking password information.

TIMING/RECONNECT OPTIONS
bind_timelimit SECONDS
Specifies the time limit (in seconds) to use when connecting to the directory
server. This is distinct from the time limit specified in timelimit and affects
the set-up of the connection only. Note that not all LDAP client libraries have
support for setting the connection time out. The default bind_timelimit is 10
seconds.

timelimit SECONDS
Specifies the time limit (in seconds) to wait for a response from the LDAP server.
A value of zero (0), which is the default, is to wait indefinitely for searches to
be completed.

idle_timelimit SECONDS
Specifies the period if inactivity (in seconds) after which the connection to the
LDAP server will be closed. The default is not to time out connections.

reconnect_sleeptime SECONDS
Specifies the number of seconds to sleep when connecting to all LDAP servers fails.
By default 1 second is waited between the first failure and the first retry.

reconnect_retrytime SECONDS
Specifies the time after which the LDAP server is considered to be permanently
unavailable. Once this time is reached retries will be done only once per this
time period. The default value is 10 seconds.

Note that the reconnect logic as described above is the mechanism that is used between
nslcd and the LDAP server. The mechanism between the NSS and PAM client libraries on one
end and nslcd on the other is simpler with a fixed compiled-in time out of a 10 seconds
for writing to nslcd and a time out of 60 seconds for reading answers. nslcd itself has a
read time out of 0.5 seconds and a write time out of 60 seconds.

SSL/TLS OPTIONS
ssl on|off|start_tls
Specifies whether to use SSL/TLS or not (the default is not to). If start_tls is
specified then StartTLS is used rather than raw LDAP over SSL. Not all LDAP client
libraries support both SSL, StartTLS and all related configuration options.

tls_reqcert never|allow|try|demand|hard
Specifies what checks to perform on a server-supplied certificate. The meaning of
the values is described in the ldap.conf(5) manual page. At least one of
tls_cacertdir and tls_cacertfile is required if peer verification is enabled.

tls_cacertdir PATH
Specifies the directory containing X.509 certificates for peer authentication.
This parameter is ignored when using GnuTLS. On Debian OpenLDAP is linked against
GnuTLS.

tls_cacertfile PATH
Specifies the path to the X.509 certificate for peer authentication.

tls_randfile PATH
Specifies the path to an entropy source. This parameter is ignored when using
GnuTLS. On Debian OpenLDAP is linked against GnuTLS.

tls_ciphers CIPHERS
Specifies the ciphers to use for TLS. See your TLS implementation's documentation
for further information.

tls_cert PATH
Specifies the path to the file containing the local certificate for client TLS
authentication.

tls_key PATH
Specifies the path to the file containing the private key for client TLS
authentication.

OTHER OPTIONS
pagesize NUMBER
Set this to a number greater than 0 to request paged results from the LDAP server
in accordance with RFC2696. The default (0) is to not request paged results.

This is useful for LDAP servers that contain a lot of entries (e.g. more than 500)
and limit the number of entries that are returned with one request. For OpenLDAP
servers you may need to set sizelimit size.prtotal=unlimited for allowing more
entries to be returned over multiple pages.

nss_initgroups_ignoreusers user1,user2,...
This option prevents group membership lookups through LDAP for the specified users.
This can be useful in case of unavailability of the LDAP server. This option may
be specified multiple times.

Alternatively, the value ALLLOCAL may be used. With that value nslcd builds a full
list of non-LDAP users on startup.

nss_min_uid UID
This option ensures that LDAP users with a numeric user id lower than the specified
value are ignored. Also requests for users with a lower user id are ignored.

validnames REGEX
This option can be used to specify how user and group names are verified within the
system. This pattern is used to check all user and group names that are requested
and returned from LDAP.

The regular expression should be specified as a POSIX extended regular expression.
The expression itself needs to be separated by slash (/) characters and the 'i'
flag may be appended at the end to indicate that the match should be case-
insensetive. The default value is /^[a-z0-9._@$][a-z0-9._@$
\\~-]*[a-z0-9._@$~-]$/i

ignorecase yes|no
This specifies whether or not to perform searches for group, netgroup, passwd,
protocols, rpc, services and shadow maps using case-insensitive matching. Setting
this to yes could open up the system to authorisation vulnerabilities and introduce
nscd cache poisoning vulnerabilities which allow denial of service. The default is
to perform case-sensitve filtering of LDAP search results for the above maps.

pam_authz_search FILTER
This option allows flexible fine tuning of the authorisation check that should be
performed. The search filter specified is executed and if any entries match, access
is granted, otherwise access is denied.

The search filter can contain the following variable references: $username,
$service, $ruser, $rhost, $tty, $hostname, $fqdn, $dn, and $uid. These references
are substituted in the search filter using the same syntax as described in the
section on attribute mapping expressions below.

For example, to check that the user has a proper authorizedService value if the
attribute is present (this almost emulates the pam_check_service_attr option in
PADL's pam_ldap):

(&(objectClass=posixAccount)(uid=$username)(|(authorizedService=$service)(!(authorizedService=*))))

The pam_check_host_attr option can be emulated with:

(&(objectClass=posixAccount)(uid=$username)(|(host=$hostname)(host=$fqdn)(host=\\*)))

This option may be specified multiple times and all specified searches should at
least return one entry for access to be granted.

pam_password_prohibit_message "MESSAGE"
If this option is set password modification using pam_ldap will be denied and the
specified message will be presented to the user instead. The message can be used
to direct the user to an alternative means of changing their password.

SUPPORTED MAPS

       The following maps are supported. They are referenced as MAP in the options above.

       alias[es]
              Mail aliases.  Note that most mail  servers  do  not  use  the  NSS  interface  for
              requesting mail aliases and parse /etc/aliases on their own.

       ether[s]
              Ethernet numbers (mac addresses).

       group  Posix groups.

       host[s]
              Host names.

       netgroup
              Host and user groups used for access control.

       network[s]
              Network numbers.

       passwd Posix users.

       protocol[s]
              Protocol definitions (like in /etc/protocols).

       rpc    Remote procedure call names and numbers.

       service[s]
              Network service names and numbers.

       shadow Shadow user password information.

ATTRIBUTE MAPPING EXPRESSIONS

       For  some  attributes  a  mapping expression may be used to construct the resulting value.
       This is currently only possible for attributes that do not  need  to  be  used  in  search
       filters.   The  expressions  are  a  subset of the double quoted string expressions in the
       Bourne (POSIX) shell.  Instead of variable substitution, attribute lookups are done on the
       current  entry  and  the  attribute  value  is substituted.  The following expressions are
       supported:

       ${attr} (or $attr for short)
              will substitute the value of the attribute

       ${attr:-word}
              (use default) will substitbute the value of the attribute or, if the  attribute  is
              not set or empty substitute the word

       ${attr:+word}
              (use  alternative)  will substitbute word if attribute is set, otherwise substitute
              the empty string

       Quote ("), dollar ($) or backslash (\) characters should be escaped with a backslash (\).

       The nslcd daemon checks the expressions to figure out which attributes to fetch from LDAP.
       Some examples to demonstrate how these expressions may be used in attribute mapping:

       "${shadowFlag:-0}"
              use the shadowFlag attribute, using the value 0 as default

       "${homeDirectory:-/home/$uid}"
              use the uid attribute to build a homeDirectory value if that attribute is missing

       "${isDisabled:+100}"
              if the isDisabled attribute is set, return 100, otherwise leave value empty

FILES

       /etc/nslcd.conf
              the main configuration file

       /etc/nsswitch.conf
              Name Service Switch configuration file

AUTHOR

       This  manual  was  written by Arthur de Jong <arthur@arthurdejong.org> and is based on the
       nss_ldap(5) manual developed by PADL Software Pty Ltd.