SSSD-LDAP

Section: File Formats and Conventions (5) Updated: 06/18/2010 Local index Up

NAME

sssd-ldap - the configuration file for SSSD

DESCRIPTION

This manual page describes the configuration of LDAP domains for sssd(8). Refer to the "FILE FORMAT" section of the sssd.conf(5) manual page for detailed syntax information.

You can configure SSSD to use more than one LDAP domain.

If you want to authenticate against an LDAP server then TLS/SSL is required. sssd does not support authentication over an unencrypted channel. If the LDAP server is used only as an identify provider, an encrypted channel is not needed.

CONFIGURATION OPTIONS

All of the common configuration options that apply to SSSD domains also apply to LDAP domains. Refer to the "DOMAIN SECTIONS" section of the sssd.conf(5) manual page for full details.

ldap_uri (string)

: Specifies the list of URIs of the LDAP servers to which SSSD should connect in the order of preference. Refer to the "FAILOVER" section for more information on failover and server redundancy. If not specified, service discovery is enabled. For more information, refer to the "SERVICE DISCOVERY" section.

ldap_search_base (string)

: The default base DN to use for performing LDAP user operations.

ldap_schema (string)

: Specifies the Schema Type in use on the target LDAP server. Depending on the selected schema, the default attribute names retrieved from the servers may vary. The way that some attributes are handled may also differ. Two schema types are currently supported: rfc2307 rfc2307bis The main difference between these two schema types is how group memberships are recorded in the server. With rfc2307, group members are listed by name in the memberUid attribute. With rfc2307bis, group members are listed by DN and stored in the member attribute.
Default: rfc2307

ldap_default_bind_dn (string)

: The default bind DN to use for performing LDAP operations.

ldap_default_authtok_type (string)

: The type of the authentication token of the default bind DN. The only currently supported value is "password".

ldap_default_authtok (string)

: The authentication token of the default bind DN. Only clear text passwords are currently supported.

ldap_user_search_base (string)

: An optional base DN to restrict user searches to a specific subtree.
Default: the value of ldap_search_base

ldap_user_object_class (string)

: The object class of a user entry in LDAP.
Default: posixAccount

ldap_user_name (string)

: The LDAP attribute that corresponds to the user's login name.
Default: uid

ldap_user_uid_number (string)

: The LDAP attribute that corresponds to the user's id.
Default: uidNumber

ldap_user_gid_number (string)

: The LDAP attribute that corresponds to the user's primary group id.
Default: gidNumber

ldap_user_gecos (string)

: The LDAP attribute that corresponds to the user's gecos field.
Default: gecos

ldap_user_home_directory (string)

: The LDAP attribute that contains the name of the user's home directory.
Default: homeDirectory

ldap_user_shell (string)

: The LDAP attribute that contains the path to the user's default shell.
Default: loginShell

ldap_user_uuid (string)

: The LDAP attribute that contains the UUID/GUID of an LDAP user object.
Default: nsUniqueId

ldap_user_principal (string)

: The LDAP attribute that contains the user's Kerberos User Principal Name (UPN).
Default: krbPrincipalName

ldap_force_upper_case_realm (boolean)

: Some directory servers, for example Active Directory, might deliver the realm part of the UPN in lower case, which might cause the authentication to fail. Set this option to a non-zero value if you want to use an upper-case realm.
Default: false

ldap_user_fullname (string)

: The LDAP attribute that corresponds to the user's full name.
Default: cn

ldap_user_member_of (string)

: The LDAP attribute that lists the user's group memberships.
Default: memberOf

ldap_group_search_base (string)

: An optional base DN to restrict group searches to a specific subtree.
Default: the value of ldap_search_base

ldap_group_object_class (string)

: The object class of a group entry in LDAP.
Default: posixGroup

ldap_group_name (string)

: The LDAP attribute that corresponds to the group name.
Default: cn

ldap_group_gid_number (string)

: The LDAP attribute that corresponds to the group's id.
Default: gidNumber

ldap_group_member (string)

: The LDAP attribute that contains the names of the group's members.
Default: memberuid (rfc2307) / member (rfc2307bis)

ldap_group_uuid (string)

: The LDAP attribute that contains the UUID/GUID of an LDAP group object.
Default: nsUniqueId

ldap_search_timeout (integer)

Specifies the timeout (in seconds) that ldap searches are allowed to run before they are cancelled and cached results are returned (and offline mode is entered)

Default: 5 (When enumerate = False)

Default: 30 (When enumerate = True - this option will be forced to a minumum of 30s in this case)

Note: this option is subject to change in future versions of the SSSD. It will likely be replaced at some point by a series of timeouts for specific lookup types.

ldap_network_timeout (integer)

: Specifies the timeout (in seconds) after which the poll(2)/select(2) following a connect(2) returns in case of no activity.
Default: 5

ldap_opt_timeout (integer)

: Specifies a timeout (in seconds) after which calls to synchronous LDAP APIs will abort if no response is received. Also controls the timeout when communicating with the KDC in case of SASL bind.
Default: 5

ldap_tls_reqcert (string)

Specifies what checks to perform on server certificates in a TLS session, if any. It can be specified as one of the following values:

never = The client will not request or check any server certificate.

allow = The server certificate is requested. If no certificate is provided, the session proceeds normally. If a bad certificate is provided, it will be ignored and the session proceeds normally.

try = The server certificate is requested. If no certificate is provided, the session proceeds normally. If a bad certificate is provided, the session is immediately terminated.

demand = The server certificate is requested. If no certificate is provided, or a bad certificate is provided, the session is immediately terminated.

hard = Same as "demand"

Default: hard

ldap_tls_cacert (string)

: Specifies the file that contains certificates for all of the Certificate Authorities that sssd will recognize.
Default: use OpenLDAP defaults, typically in /etc/openldap/ldap.conf

ldap_tls_cacertdir (string)

: Specifies the path of a directory that contains Certificate Authority certificates in separate individual files. Typically the file names need to be the hash of the certificate followed by '.0'. If available, cacertdir_rehash can be used to create the correct names.
Default: use OpenLDAP defaults, typically in /etc/openldap/ldap.conf

ldap_id_use_start_tls (boolean)

: Specifies that the id_provider connection must also use tls to protect the channel.
Default: false

ldap_sasl_mech (string)

: Specify the SASL mechanism to use. Currently only GSSAPI is tested and supported.
Default: none

ldap_sasl_authid (string)

: Specify the SASL authorization id to use. When GSSAPI is used, this represents the Kerberos principal used for authentication to the directory.
Default: host/machine.fqdn@REALM

ldap_krb5_keytab (string)

: Specify the keytab to use when using SASL/GSSAPI.
Default: System keytab, normally /etc/krb5.keytab

ldap_krb5_init_creds (boolean)

: Specifies that the id_provider should init Kerberos credentials (TGT). This action is performed only if SASL is used and the mechanism selected is GSSAPI.
Default: true

ldap_krb5_ticket_lifetime (integer)

: Specifies the lifetime in seconds of the TGT if GSSAPI is used.
Default: 86400 (24 hours)

krb5_realm (string)

: Specify the Kerberos REALM (for SASL/GSSAPI auth).
Default: System defaults, see /etc/krb5.conf

ldap_pwd_policy (string)

Select the policy to evaluate the password expiration on the client side. The following values are allowed:

none - No evaluation on the client side. This option cannot disable server-side password policies.

shadow - Use shadow(5) style attributes to evaluate if the password has expired. Note that the current version of sssd cannot update this attribute during a password change.

mit_kerberos - Use the attributes used by MIT Kerberos to determine if the password has expired. Use chpass_provider=krb5 to update these attributes when the password is changed.

Default: none

ldap_referrals (boolean)

Specifies whether automatic referral chasing should be enabled.

Please note that sssd only supports referral chasing when it is compiled with OpenLDAP version 2.4.13 or higher.

Default: true

ldap_dns_service_name (string)

: Specifies the service name to use when service discovery is enabled.
Default: ldap

ldap_access_filter (string)

If using access_provider = ldap, this option is mandatory. It specifies an LDAP search filter criteria that must be met for the user to be granted access on this host. If access_provider = ldap and this option is not set, it will result in all users being denied access. Use access_provider = allow to change this default behavior.

Example:

access_provider = ldap
ldap_access_filter = memberOf=cn=allowedusers,ou=Groups,dc=example,dc=com

This example means that access to this host is restricted to members of the "allowedusers" group in ldap.

Offline caching for this feature is limited to determining whether the user's last online login was granted access permission. If they were granted access during their last login, they will continue to be granted access while offline and vice-versa.

Default: Empty

FAILOVER

The failover feature allows back ends to automatically switch to a different server if the primary server fails.

Failover Syntax

The list of servers is given as a comma-separated list; any number of spaces is allowed around the comma. The servers are listed in order of preference. The list can contain any number of servers.

The Failover Mechanism

The failover mechanism distinguishes between a machine and a service. The back end first tries to resolve the hostname of a given machine; if this resolution attempt fails, the machine is considered offline. No further attempts are made to connect to this machine for any other service. If the resolution attempt succeeds, the back end tries to connect to a service on this machine. If the service connection attempt fails, then only this particular service is considered offline and the back end automatically switches over to the next service. The machine is still considered online and might still be tried for another service.

Further connection attempts are made to machines or services marked as offline after a specified period of time; this is currently hard coded to 30 seconds.

If there are no more machines to try, the back end as a whole switches to offline mode, and then attempts to reconnect every 30 seconds.

SERVICE DISCOVERY

The service discovery feature allows back ends to automatically find the appropriate servers to connect to using a special DNS query.

Configuration

If no servers are specified, the back end automatically uses service discovery to try to find a server. Optionally, the user may choose to use both fixed server addresses and service discovery by inserting a special keyword, "_srv_", in the list of servers. The order of preference is maintained. This feature is useful if, for example, the user prefers to use service discovery whenever possible, and fall back to a specific server when no servers can be discovered using DNS.

The domain name

The name of the SSSD domain is used as the domain part of the service discovery DNS query.

EXAMPLE

The following example assumes that SSSD is correctly configured and LDAP is set to one of the domains in the [domains] section.

    [domain/LDAP]
    id_provider = ldap
    auth_provider = ldap
    ldap_uri = ldap://ldap.mydomain.org
    ldap_search_base = dc=mydomain,dc=org
    ldap_tls_reqcert = demand
    cache_credentials = true
    enumerate = true

NOTES

The descriptions of some of the configuration options in this manual page are based on the ldap.conf(5) manual page from the OpenLDAP 2.4 distribution.