NAME
sssd-ldap - SSSD LDAP providerDESCRIPTION
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. LDAP back end supports id, auth, access and chpass providers. If you want to authenticate against an LDAP server either TLS/SSL or LDAPS is required. sssd does not support authentication over an unencrypted channel. If the LDAP server is used only as an identity provider, an encrypted channel is not needed. Please refer to “ldap_access_filter” config option for more information about using LDAP as an access provider.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. Note that SSSD LDAP mapping attributes are described in the sssd-ldap-attributes(5) manual page. ldap_uri, ldap_backup_uri (string)Specifies the comma-separated 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 neither option is specified, service discovery is
enabled. For more information, refer to the “SERVICE DISCOVERY”
section.
The format of the URI must match the format defined in RFC 2732:
ldap[s]://<host>[:port]
For explicit IPv6 addresses, <host> must be enclosed in brackets []
example: ldap://[fc00::126:25]:389
ldap_chpass_uri, ldap_chpass_backup_uri (string)
Specifies the comma-separated list of URIs of
the LDAP servers to which SSSD should connect in the order of preference to
change the password of a user. Refer to the “FAILOVER” section
for more information on failover and server redundancy.
To enable service discovery ldap_chpass_dns_service_name must be set.
Default: empty, i.e. ldap_uri is used.
ldap_search_base (string)
The default base DN to use for performing LDAP
user operations.
Starting with SSSD 1.7.0, SSSD supports multiple search bases using the syntax:
search_base[?scope?[filter][?search_base?scope?[filter]]*]
The scope can be one of "base", "onelevel" or
"subtree".
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
Examples:
ldap_search_base = dc=example,dc=com (which is equivalent to) ldap_search_base =
dc=example,dc=com?subtree?
ldap_search_base =
cn=host_specific,dc=example,dc=com?subtree?(host=thishost)?dc=example.com?subtree?
Note: It is unsupported to have multiple search bases which reference
identically-named objects (for example, groups with the same name in two
different search bases). This will lead to unpredictable behavior on client
machines.
Default: If not set, the value of the defaultNamingContext or namingContexts
attribute from the RootDSE of the LDAP server is used. If defaultNamingContext
does not exist or has an empty value namingContexts is used. The
namingContexts attribute must have a single value with the DN of the search
base of the LDAP server to make this work. Multiple values are are not
supported.
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.
Four schema types are currently supported:
The main difference between these 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 and IPA, group members are listed
by DN and stored in the member attribute. The AD schema type sets the
attributes to correspond with Active Directory 2008r2 values.
Default: rfc2307
ldap_pwmodify_mode (string)
•rfc2307
•rfc2307bis
•IPA
•AD
Specify the operation that is used to modify
user password.
Two modes are currently supported:
Note: First, a new connection is established to verify current password by
binding as the user that requested password change. If successful, this
connection is used to change the password therefore the user must have write
access to userPassword attribute.
Default: exop
ldap_default_bind_dn (string)
•exop - Password Modify Extended
Operation (RFC 3062)
•ldap_modify - Direct modification of
userPassword (not recommended).
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 two mechanisms currently supported are:
password
obfuscated_password
Default: password
See the sss_obfuscate(8) manual page for more information.
ldap_default_authtok (string)
The authentication token of the default bind
DN.
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_enumeration_refresh_timeout (integer)
Specifies how many seconds SSSD has to wait
before refreshing its cache of enumerated records.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 300
ldap_purge_cache_timeout (integer)
Determine how often to check the cache for
inactive entries (such as groups with no members and users who have never
logged in) and remove them to save space.
Setting this option to zero will disable the cache cleanup operation. Please
note that if enumeration is enabled, the cleanup task is required in order to
detect entries removed from the server and can't be disabled. By default, the
cleanup task will run every 3 hours with enumeration enabled.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 0 (disabled)
ldap_group_nesting_level (integer)
If ldap_schema is set to a schema format that
supports nested groups (e.g. RFC2307bis), then this option controls how many
levels of nesting SSSD will follow. This option has no effect on the RFC2307
schema.
Note: This option specifies the guaranteed level of nested groups to be
processed for any lookup. However, nested groups beyond this limit may
be returned if previous lookups already resolved the deeper nesting
levels. Also, subsequent lookups for other groups may enlarge the result set
for original lookup if re-queried.
If ldap_group_nesting_level is set to 0 then no nested groups are processed at
all. However, when connected to Active-Directory Server 2008 and later using
“id_provider=ad” it is furthermore required to disable usage of
Token-Groups by setting ldap_use_tokengroups to false in order to restrict
group nesting.
Default: 2
ldap_use_tokengroups
This options enables or disables use of
Token-Groups attribute when performing initgroup for users from Active
Directory Server 2008 and later.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: True for AD and IPA otherwise False.
ldap_host_search_base (string)
Optional. Use the given string as search base
for host objects.
See “ldap_search_base” for information about configuring multiple
search bases.
Default: the value of ldap_search_base
ldap_service_search_base (string)
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_iphost_search_base (string)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_ipnetwork_search_base (string)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_search_timeout (integer)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
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)
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.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 6
ldap_enumeration_search_timeout (integer)
Specifies the timeout (in seconds) that ldap
searches for user and group enumerations are allowed to run before they are
cancelled and cached results are returned (and offline mode is entered)
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 60
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.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 6
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, the
timeout of an LDAP bind operation, password change extended operation and the
StartTLS operation.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 8
ldap_connection_expire_timeout (integer)
Specifies a timeout (in seconds) that a
connection to an LDAP server will be maintained. After this time, the
connection will be re-established. If used in parallel with SASL/GSSAPI, the
sooner of the two values (this value vs. the TGT lifetime) will be used.
If the connection is idle (not actively running an operation) within
ldap_opt_timeout seconds of expiration, then it will be closed early to
ensure that a new query cannot require the connection to remain open past its
expiration. This implies that connections will always be closed immediately
and will never be reused if ldap_connection_expire_timeout <=
ldap_opt_timout
This timeout can be extended of a random value specified by
ldap_connection_expire_offset
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 900 (15 minutes)
ldap_connection_expire_offset (integer)
Random offset between 0 and configured value
is added to ldap_connection_expire_timeout.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 0
ldap_connection_idle_timeout (integer)
Specifies a timeout (in seconds) that an idle
connection to an LDAP server will be maintained. If the connection is idle for
more than this time then the connection will be closed.
You can disable this timeout by setting the value to 0.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 900 (15 minutes)
ldap_page_size (integer)
Specify the number of records to retrieve from
LDAP in a single request. Some LDAP servers enforce a maximum limit
per-request.
Default: 1000
ldap_disable_paging (boolean)
Disable the LDAP paging control. This option
should be used if the LDAP server reports that it supports the LDAP paging
control in its RootDSE but it is not enabled or does not behave properly.
Example: OpenLDAP servers with the paging control module installed on the server
but not enabled will report it in the RootDSE but be unable to use it.
Example: 389 DS has a bug where it can only support a one paging control at a
time on a single connection. On busy clients, this can result in some requests
being denied.
Default: False
ldap_disable_range_retrieval (boolean)
Disable Active Directory range retrieval.
Active Directory limits the number of members to be retrieved in a single lookup
using the MaxValRange policy (which defaults to 1500 members). If a group
contains more members, the reply would include an AD-specific range extension.
This option disables parsing of the range extension, therefore large groups
will appear as having no members.
Default: False
ldap_sasl_minssf (integer)
When communicating with an LDAP server using
SASL, specify the minimum security level necessary to establish the
connection. The values of this option are defined by OpenLDAP.
Default: Use the system default (usually specified by ldap.conf)
ldap_sasl_maxssf (integer)
When communicating with an LDAP server using
SASL, specify the maximal security level necessary to establish the
connection. The values of this option are defined by OpenLDAP.
Default: Use the system default (usually specified by ldap.conf)
ldap_deref_threshold (integer)
Specify the number of group members that must
be missing from the internal cache in order to trigger a dereference lookup.
If less members are missing, they are looked up individually.
You can turn off dereference lookups completely by setting the value to 0.
Please note that there are some codepaths in SSSD, like the IPA HBAC provider,
that are only implemented using the dereference call, so even with dereference
explicitly disabled, those parts will still use dereference if the server
supports it and advertises the dereference control in the rootDSE object.
A dereference lookup is a means of fetching all group members in a single LDAP
call. Different LDAP servers may implement different dereference methods. The
currently supported servers are 389/RHDS, OpenLDAP and Active Directory.
Note: If any of the search bases specifies a search filter, then the
dereference lookup performance enhancement will be disabled regardless of this
setting.
Default: 10
ldap_ignore_unreadable_references (bool)
Ignore unreadable LDAP entries referenced in
group's member attribute. If this parameter is set to false an error will be
returned and the operation will fail instead of just ignoring the unreadable
entry.
This parameter may be useful when using the AD provider and the computer account
that sssd uses to connect to AD does not have access to a particular entry or
LDAP sub-tree for security reasons.
Default: False
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_tls_cert (string)
Specifies the file that contains the
certificate for the client's key.
Default: not set
ldap_tls_key (string)
Specifies the file that contains the client's
key.
Default: not set
ldap_tls_cipher_suite (string)
Specifies acceptable cipher suites. Typically
this is a colon separated list. See ldap.conf(5) for format.
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_id_mapping (boolean)
Specifies that SSSD should attempt to map user
and group IDs from the ldap_user_objectsid and ldap_group_objectsid attributes
instead of relying on ldap_user_uid_number and ldap_group_gid_number.
Currently this feature supports only ActiveDirectory objectSID mapping.
Default: false
ldap_min_id, ldap_max_id (integer)
In contrast to the SID based ID mapping which
is used if ldap_id_mapping is set to true the allowed ID range for
ldap_user_uid_number and ldap_group_gid_number is unbound. In a setup with
sub/trusted-domains this might lead to ID collisions. To avoid collisions
ldap_min_id and ldap_max_id can be set to restrict the allowed range for the
IDs which are read directly from the server. Sub-domains can then pick other
ranges to map IDs.
Default: not set (both options are set to 0)
ldap_sasl_mech (string)
Specify the SASL mechanism to use. Currently
only GSSAPI and GSS-SPNEGO are tested and supported.
If the backend supports sub-domains the value of ldap_sasl_mech is automatically
inherited to the sub-domains. If a different value is needed for a sub-domain
it can be overwritten by setting ldap_sasl_mech for this sub-domain
explicitly. Please see TRUSTED DOMAIN SECTION in sssd.conf(5) for
details.
Default: not set
ldap_sasl_authid (string)
Specify the SASL authorization id to use. When
GSSAPI/GSS-SPNEGO are used, this represents the Kerberos principal used for
authentication to the directory. This option can either contain the full
principal (for example host/[email protected]) or just the principal name
(for example host/myhost). By default, the value is not set and the following
principals are used:
If none of them are found, the first principal in keytab is returned.
Default: host/hostname@REALM
ldap_sasl_realm (string)
hostname@REALM netbiosname$@REALM host/hostname@REALM *$@REALM host/*@REALM host/*
Specify the SASL realm to use. When not
specified, this option defaults to the value of krb5_realm. If the
ldap_sasl_authid contains the realm as well, this option is ignored.
Default: the value of krb5_realm.
ldap_sasl_canonicalize (boolean)
If set to true, the LDAP library would perform
a reverse lookup to canonicalize the host name during a SASL bind.
Default: false;
ldap_krb5_keytab (string)
Specify the keytab to use when using
SASL/GSSAPI/GSS-SPNEGO.
This option can be also set per subdomain or inherited via
subdomain_inherit.
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 or GSS-SPNEGO.
Default: true
ldap_krb5_ticket_lifetime (integer)
Specifies the lifetime in seconds of the TGT
if GSSAPI or GSS-SPNEGO is used.
This option can be also set per subdomain or inherited via
subdomain_inherit.
Default: 86400 (24 hours)
krb5_server, krb5_backup_server (string)
Specifies the comma-separated list of IP
addresses or hostnames of the Kerberos servers to which SSSD should connect in
the order of preference. For more information on failover and server
redundancy, see the “FAILOVER” section. An optional port number
(preceded by a colon) may be appended to the addresses or hostnames. If empty,
service discovery is enabled - for more information, refer to the
“SERVICE DISCOVERY” section.
When using service discovery for KDC or kpasswd servers, SSSD first searches for
DNS entries that specify _udp as the protocol and falls back to _tcp if none
are found.
This option was named “krb5_kdcip” in earlier releases of SSSD.
While the legacy name is recognized for the time being, users are advised to
migrate their config files to use “krb5_server” instead.
krb5_realm (string)
Specify the Kerberos REALM (for
SASL/GSSAPI/GSS-SPNEGO auth).
Default: System defaults, see /etc/krb5.conf
krb5_canonicalize (boolean)
Specifies if the host principal should be
canonicalized when connecting to LDAP server. This feature is available with
MIT Kerberos >= 1.7
Default: false
krb5_use_kdcinfo (boolean)
Specifies if the SSSD should instruct the
Kerberos libraries what realm and which KDCs to use. This option is on by
default, if you disable it, you need to configure the Kerberos library using
the krb5.conf(5) configuration file.
See the sssd_krb5_locator_plugin(8) manual page for more information on
the locator plugin.
Default: true
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. Please see option
"ldap_chpass_update_last_change" as well.
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
Note: if a password policy is configured on server side, it always takes
precedence over policy set with this option.
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.
Chasing referrals may incur a performance penalty in environments that use them
heavily, a notable example is Microsoft Active Directory. If your setup does
not in fact require the use of referrals, setting this option to false might
bring a noticeable performance improvement. Setting this option to false is
therefore recommended in case the SSSD LDAP provider is used together with
Microsoft Active Directory as a backend. Even if SSSD would be able to follow
the referral to a different AD DC no additional data would be available.
Default: true
ldap_dns_service_name (string)
Specifies the service name to use when service
discovery is enabled.
Default: ldap
ldap_chpass_dns_service_name (string)
Specifies the service name to use to find an
LDAP server which allows password changes when service discovery is enabled.
Default: not set, i.e. service discovery is disabled
ldap_chpass_update_last_change (bool)
Specifies whether to update the
ldap_user_shadow_last_change attribute with days since the Epoch after a
password change operation.
It is recommend to set this option explicitly if "ldap_pwd_policy =
shadow" is used to let SSSD know if the LDAP server will update
shadowLastChange LDAP attribute automatically after a password change or if
SSSD has to update it.
Default: False
ldap_access_filter (string)
If using access_provider = ldap and
ldap_access_order = filter (default), 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, ldap_access_order = filter and
this option is not set, it will result in all users being denied access. Use
access_provider = permit to change this default behavior. Please note that
this filter is applied on the LDAP user entry only and thus filtering based on
nested groups may not work (e.g. memberOf attribute on AD entries points only
to direct parents). If filtering based on nested groups is required, please
see sssd-simple(5).
Example:
This example means that access to this host is restricted to users whose
employeeType attribute is set to "admin".
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
ldap_account_expire_policy (string)
access_provider = ldap ldap_access_filter = (employeeType=admin)
With this option a client side evaluation of
access control attributes can be enabled.
Please note that it is always recommended to use server side access control,
i.e. the LDAP server should deny the bind request with a suitable error code
even if the password is correct.
The following values are allowed:
shadow: use the value of ldap_user_shadow_expire to determine if the
account is expired.
ad: use the value of the 32bit field ldap_user_ad_user_account_control
and allow access if the second bit is not set. If the attribute is missing
access is granted. Also the expiration time of the account is checked.
rhds, ipa, 389ds: use the value of ldap_ns_account_lock to
check if access is allowed or not.
nds: the values of ldap_user_nds_login_allowed_time_map,
ldap_user_nds_login_disabled and ldap_user_nds_login_expiration_time are used
to check if access is allowed. If both attributes are missing access is
granted. This is an experimental feature, please use
https://github.com/SSSD/sssd/ to report any issues.
Please note that the ldap_access_order configuration option must include
“expire” in order for the ldap_account_expire_policy option to
work.
Default: Empty
ldap_access_order (string)
Comma separated list of access control
options. Allowed values are:
filter: use ldap_access_filter
lockout: use account locking. If set, this option denies access in case
that ldap attribute 'pwdAccountLockedTime' is present and has value of
'000001010000Z'. Please see the option ldap_pwdlockout_dn. Please note that
'access_provider = ldap' must be set for this feature to work.
Please note that this option is superseded by the
“ppolicy” option and might be removed in a future
release.
ppolicy: use account locking. If set, this option denies access in case
that ldap attribute 'pwdAccountLockedTime' is present and has value of
'000001010000Z' or represents any time in the past. The value of the
'pwdAccountLockedTime' attribute must end with 'Z', which denotes the UTC time
zone. Other time zones are not currently supported and will result in
"access-denied" when users attempt to log in. Please see the option
ldap_pwdlockout_dn. Please note that 'access_provider = ldap' must be set for
this feature to work.
expire: use ldap_account_expire_policy
pwd_expire_policy_reject, pwd_expire_policy_warn, pwd_expire_policy_renew:
These options are useful if users are interested in being warned that
password is about to expire and authentication is based on using a different
method than passwords - for example SSH keys.
The difference between these options is the action taken if user password is
expired: pwd_expire_policy_reject - user is denied to log in,
pwd_expire_policy_warn - user is still able to log in, pwd_expire_policy_renew
- user is prompted to change his password immediately.
Note If user password is expired no explicit message is prompted by SSSD.
Please note that 'access_provider = ldap' must be set for this feature to work.
Also 'ldap_pwd_policy' must be set to an appropriate password policy.
authorized_service: use the authorizedService attribute to determine
access
host: use the host attribute to determine access
rhost: use the rhost attribute to determine whether remote host can
access
Please note, rhost field in pam is set by application, it is better to check
what the application sends to pam, before enabling this access control option
Default: filter
Please note that it is a configuration error if a value is used more than
once.
ldap_pwdlockout_dn (string)
This option specifies the DN of password
policy entry on LDAP server. Please note that absence of this option in
sssd.conf in case of enabled account lockout checking will yield access denied
as ppolicy attributes on LDAP server cannot be checked properly.
Example: cn=ppolicy,ou=policies,dc=example,dc=com
Default: cn=ppolicy,ou=policies,$ldap_search_base
ldap_deref (string)
Specifies how alias dereferencing is done when
performing a search. The following options are allowed:
never: Aliases are never dereferenced.
searching: Aliases are dereferenced in subordinates of the base object,
but not in locating the base object of the search.
finding: Aliases are only dereferenced when locating the base object of
the search.
always: Aliases are dereferenced both in searching and in locating the
base object of the search.
Default: Empty (this is handled as never by the LDAP client
libraries)
ldap_rfc2307_fallback_to_local_users (boolean)
Allows to retain local users as members of an
LDAP group for servers that use the RFC2307 schema.
In some environments where the RFC2307 schema is used, local users are made
members of LDAP groups by adding their names to the memberUid attribute. The
self-consistency of the domain is compromised when this is done, so SSSD would
normally remove the "missing" users from the cached group
memberships as soon as nsswitch tries to fetch information about the user via
getpw*() or initgroups() calls.
This option falls back to checking if local users are referenced, and caches
them so that later initgroups() calls will augment the local users with the
additional LDAP groups.
Default: false
wildcard_limit (integer)
Specifies an upper limit on the number of
entries that are downloaded during a wildcard lookup.
At the moment, only the InfoPipe responder supports wildcard lookups.
Default: 1000 (often the size of one page)
ldap_library_debug_level (integer)
Switches on libldap debugging with the given
level. The libldap debug messages will be written independent of the general
debug_level.
OpenLDAP uses a bitmap to enable debugging for specific components, -1 will
enable full debug output.
Default: 0 (libldap debugging disabled)
SUDO OPTIONS
The detailed instructions for configuration of sudo_provider are in the manual page sssd-sudo(5). ldap_sudo_full_refresh_interval (integer)How many seconds SSSD will wait between
executing a full refresh of sudo rules (which downloads all rules that are
stored on the server).
The value must be greater than ldap_sudo_smart_refresh_interval
You can disable full refresh by setting this option to 0. However, either smart
or full refresh must be enabled.
Default: 21600 (6 hours)
ldap_sudo_smart_refresh_interval (integer)
How many seconds SSSD has to wait before
executing a smart refresh of sudo rules (which downloads all rules that have
USN higher than the highest server USN value that is currently known by SSSD).
If USN attributes are not supported by the server, the modifyTimestamp attribute
is used instead.
Note: the highest USN value can be updated by three tasks: 1) By sudo
full and smart refresh (if updated rules are found), 2) by enumeration of
users and groups (if enabled and updated users or groups are found) and 3) by
reconnecting to the server (by default every 15 minutes, see
ldap_connection_expire_timeout).
You can disable smart refresh by setting this option to 0. However, either smart
or full refresh must be enabled.
Default: 900 (15 minutes)
ldap_sudo_random_offset (integer)
Random offset between 0 and configured value
is added to smart and full refresh periods each time the periodic task is
scheduled. The value is in seconds.
Note that this random offset is also applied on the first SSSD start which
delays the first sudo rules refresh. This prolongs the time when the sudo
rules are not available for use.
You can disable this offset by setting the value to 0.
Default: 0 (disabled)
ldap_sudo_use_host_filter (boolean)
If true, SSSD will download only rules that
are applicable to this machine (using the IPv4 or IPv6 host/network addresses
and hostnames).
Default: true
ldap_sudo_hostnames (string)
Space separated list of hostnames or fully
qualified domain names that should be used to filter the rules.
If this option is empty, SSSD will try to discover the hostname and the fully
qualified domain name automatically.
If ldap_sudo_use_host_filter is false then this option has no
effect.
Default: not specified
ldap_sudo_ip (string)
Space separated list of IPv4 or IPv6
host/network addresses that should be used to filter the rules.
If this option is empty, SSSD will try to discover the addresses automatically.
If ldap_sudo_use_host_filter is false then this option has no
effect.
Default: not specified
ldap_sudo_include_netgroups (boolean)
If true then SSSD will download every rule
that contains a netgroup in sudoHost attribute.
If ldap_sudo_use_host_filter is false then this option has no
effect.
Default: true
ldap_sudo_include_regexp (boolean)
If true then SSSD will download every rule
that contains a wildcard in sudoHost attribute.
If ldap_sudo_use_host_filter is false then this option has no
effect.
Note
Using wildcard is an operation that is very costly to evaluate on the LDAP
server side!
Default: false
This manual page only describes attribute name mapping. For detailed explanation
of sudo related attribute semantics, see sudoers.ldap(5)
AUTOFS OPTIONS
Some of the defaults for the parameters below are dependent on the LDAP schema. ldap_autofs_map_master_name (string)The name of the automount master map in LDAP.
Default: auto.master
ldap_autofs_map_object_class (string)
The object class of an automount map entry in
LDAP.
Default: nisMap (rfc2307, autofs_provider=ad), otherwise automountMap
ldap_autofs_map_name (string)
The name of an automount map entry in LDAP.
Default: nisMapName (rfc2307, autofs_provider=ad), otherwise
automountMapName
ldap_autofs_entry_object_class (string)
The object class of an automount entry in
LDAP. The entry usually corresponds to a mount point.
Default: nisObject (rfc2307, autofs_provider=ad), otherwise automount
ldap_autofs_entry_key (string)
The key of an automount entry in LDAP. The
entry usually corresponds to a mount point.
Default: cn (rfc2307, autofs_provider=ad), otherwise automountKey
ldap_autofs_entry_value (string)
The key of an automount entry in LDAP. The
entry usually corresponds to a mount point.
Default: nisMapEntry (rfc2307, autofs_provider=ad), otherwise
automountInformation
Please note that the automounter only reads the master map on startup, so if any
autofs-related changes are made to the sssd.conf, you typically also need to
restart the automounter daemon after restarting the SSSD.
ADVANCED OPTIONS
These options are supported by LDAP domains, but they should be used with caution. Please include them in your configuration only if you know what you are doing. ldap_netgroup_search_base (string)An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_user_search_base (string)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_group_search_base (string)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
ldap_autofs_search_base (string)
search_base[?scope?[filter][?search_base?scope?[filter]]*]
An optional base DN, search scope and LDAP
filter to restrict LDAP searches for this attribute type.
syntax:
The scope can be one of "base", "onelevel" or
"subtree". The scope functions as specified in section 4.5.1.2 of
http://tools.ietf.org/html/rfc4511
The filter must be a valid LDAP search filter as specified by
http://www.ietf.org/rfc/rfc2254.txt
For examples of this syntax, please refer to the
“ldap_search_base” examples section.
Default: the value of ldap_search_base
Please note that specifying scope or filter is not supported for searches
against an Active Directory Server that might yield a large number of results
and trigger the Range Retrieval extension in the response.
search_base[?scope?[filter][?search_base?scope?[filter]]*]
FAILOVER
The failover feature allows back ends to automatically switch to a different server if the current 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. For each failover-enabled config option, two variants exist: primary and backup. The idea is that servers in the primary list are preferred and backup servers are only searched if no primary servers can be reached. If a backup server is selected, a timeout of 31 seconds is set. After this timeout SSSD will periodically try to reconnect to one of the primary servers. If it succeeds, it will replace the current active (backup) server.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.Failover time outs and tuning
Resolving a server to connect to can be as simple as running a single DNS query or can involve several steps, such as finding the correct site or trying out multiple host names in case some of the configured servers are not reachable. The more complex scenarios can take some time and SSSD needs to balance between providing enough time to finish the resolution process but on the other hand, not trying for too long before falling back to offline mode. If the SSSD debug logs show that the server resolution is timing out before a live server is contacted, you can consider changing the time outs. This section lists the available tunables. Please refer to their description in the sssd.conf(5), manual page. dns_resolver_server_timeoutTime in milliseconds that sets how long would
SSSD talk to a single DNS server before trying next one.
Default: 1000
dns_resolver_op_timeout
Time in seconds to tell how long would SSSD
try to resolve single DNS query (e.g. resolution of a hostname or an SRV
record) before trying the next hostname or discovery domain.
Default: 3
dns_resolver_timeout
How long would SSSD try to resolve a failover
service. This service resolution internally might include several steps, such
as resolving DNS SRV queries or locating the site.
Default: 6
For LDAP-based providers, the resolve operation is performed as part of an LDAP
connection operation. Therefore, also the “ldap_opt_timeout”
timeout should be set to a larger value than
“dns_resolver_timeout” which in turn should be set to a larger
value than “dns_resolver_op_timeout” which should be larger than
“dns_resolver_server_timeout”.
SERVICE DISCOVERY
The service discovery feature allows back ends to automatically find the appropriate servers to connect to using a special DNS query. This feature is not supported for backup servers.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
Please refer to the “dns_discovery_domain” parameter in the sssd.conf(5) manual page for more details.The protocol
The queries usually specify _tcp as the protocol. Exceptions are documented in respective option description.See Also
For more information on the service discovery mechanism, refer to RFC 2782.ID MAPPING
The ID-mapping feature allows SSSD to act as a client of Active Directory without requiring administrators to extend user attributes to support POSIX attributes for user and group identifiers. NOTE: When ID-mapping is enabled, the uidNumber and gidNumber attributes are ignored. This is to avoid the possibility of conflicts between automatically-assigned and manually-assigned values. If you need to use manually-assigned values, ALL values must be manually-assigned. Please note that changing the ID mapping related configuration options will cause user and group IDs to change. At the moment, SSSD does not support changing IDs, so the SSSD database must be removed. Because cached passwords are also stored in the database, removing the database should only be performed while the authentication servers are reachable, otherwise users might get locked out. In order to cache the password, an authentication must be performed. It is not sufficient to use sss_cache(8) to remove the database, rather the process consists of:•Making sure the remote servers are
reachable
•Stopping the SSSD service
•Removing the database
•Starting the SSSD service
Mapping Algorithm
Active Directory provides an objectSID for every user and group object in the directory. This objectSID can be broken up into components that represent the Active Directory domain identity and the relative identifier (RID) of the user or group object. The SSSD ID-mapping algorithm takes a range of available UIDs and divides it into equally-sized component sections - called "slices"-. Each slice represents the space available to an Active Directory domain. When a user or group entry for a particular domain is encountered for the first time, the SSSD allocates one of the available slices for that domain. In order to make this slice-assignment repeatable on different client machines, we select the slice based on the following algorithm: The SID string is passed through the murmurhash3 algorithm to convert it to a 32-bit hashed value. We then take the modulus of this value with the total number of available slices to pick the slice. NOTE: It is possible to encounter collisions in the hash and subsequent modulus. In these situations, we will select the next available slice, but it may not be possible to reproduce the same exact set of slices on other machines (since the order that they are encountered will determine their slice). In this situation, it is recommended to either switch to using explicit POSIX attributes in Active Directory (disabling ID-mapping) or configure a default domain to guarantee that at least one is always consistent. See “Configuration” for details.Configuration
Minimum configuration (in the “[domain/DOMAINNAME]” section):ldap_id_mapping = True ldap_schema = ad
ldap_idmap_range_min (integer)
Specifies the lower (inclusive) bound of the
range of POSIX IDs to use for mapping Active Directory user and group SIDs. It
is the first POSIX ID which can be used for the mapping.
NOTE: This option is different from “min_id” in that
“min_id” acts to filter the output of requests to this domain,
whereas this option controls the range of ID assignment. This is a subtle
distinction, but the good general advice would be to have
“min_id” be less-than or equal to
“ldap_idmap_range_min”
Default: 200000
ldap_idmap_range_max (integer)
Specifies the upper (exclusive) bound of the
range of POSIX IDs to use for mapping Active Directory user and group SIDs. It
is the first POSIX ID which cannot be used for the mapping anymore, i.e. one
larger than the last one which can be used for the mapping.
NOTE: This option is different from “max_id” in that
“max_id” acts to filter the output of requests to this domain,
whereas this option controls the range of ID assignment. This is a subtle
distinction, but the good general advice would be to have
“max_id” be greater-than or equal to
“ldap_idmap_range_max”
Default: 2000200000
ldap_idmap_range_size (integer)
Specifies the number of IDs available for each
slice. If the range size does not divide evenly into the min and max values,
it will create as many complete slices as it can.
NOTE: The value of this option must be at least as large as the highest user RID
planned for use on the Active Directory server. User lookups and login will
fail for any user whose RID is greater than this value.
For example, if your most recently-added Active Directory user has
objectSid=S-1-5-21-2153326666-2176343378-3404031434-1107,
“ldap_idmap_range_size” must be at least 1108 as range size is
equal to maximal SID minus minimal SID plus one (e.g. 1108 = 1107 - 0 + 1).
It is important to plan ahead for future expansion, as changing this value will
result in changing all of the ID mappings on the system, leading to users with
different local IDs than they previously had.
Default: 200000
ldap_idmap_default_domain_sid (string)
Specify the domain SID of the default domain.
This will guarantee that this domain will always be assigned to slice zero in
the ID map, bypassing the murmurhash algorithm described above.
Default: not set
ldap_idmap_default_domain (string)
Specify the name of the default domain.
Default: not set
ldap_idmap_autorid_compat (boolean)
Changes the behavior of the ID-mapping
algorithm to behave more similarly to winbind's “idmap_autorid”
algorithm.
When this option is configured, domains will be allocated starting with slice
zero and increasing monatomically with each additional domain.
NOTE: This algorithm is non-deterministic (it depends on the order that users
and groups are requested). If this mode is required for compatibility with
machines running winbind, it is recommended to also use the
“ldap_idmap_default_domain_sid” option to guarantee that at
least one domain is consistently allocated to slice zero.
Default: False
ldap_idmap_helper_table_size (integer)
Maximal number of secondary slices that is
tried when performing mapping from UNIX id to SID.
Note: Additional secondary slices might be generated when SID is being mapped to
UNIX id and RID part of SID is out of range for secondary slices generated so
far. If value of ldap_idmap_helper_table_size is equal to 0 then no additional
secondary slices are generated.
Default: 10
Well-Known SIDs
SSSD supports to look up the names of Well-Known SIDs, i.e. SIDs with a special hardcoded meaning. Since the generic users and groups related to those Well-Known SIDs have no equivalent in a Linux/UNIX environment no POSIX IDs are available for those objects. The SID name space is organized in authorities which can be seen as different domains. The authorities for the Well-Known SIDs are•Null Authority
•World Authority
•Local Authority
•Creator Authority
•Mandatory Label Authority
•Authentication Authority
•NT Authority
•Built-in
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
LDAP ACCESS FILTER EXAMPLE
The following example assumes that SSSD is correctly configured and to use the ldap_access_order=lockout.[domain/LDAP] id_provider = ldap auth_provider = ldap access_provider = ldap ldap_access_order = lockout ldap_pwdlockout_dn = cn=ppolicy,ou=policies,dc=mydomain,dc=org ldap_uri = ldap://ldap.mydomain.org ldap_search_base = dc=mydomain,dc=org ldap_tls_reqcert = demand cache_credentials = 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.SEE ALSO
sssd(8), sssd.conf(5), , sssd-krb5(5), sssd-simple(5), sssd-ipa(5), sssd-ad(5), sssd-files(5), sssd-sudo(5), sssd-session-recording(5), sss_cache(8), sss_debuglevel(8), sss_obfuscate(8), sss_seed(8), sssd_krb5_locator_plugin(8), sss_ssh_authorizedkeys(8), sss_ssh_knownhostsproxy(8), sssd-ifp(5), pam_sss(8). sss_rpcidmapd(5) sssd-systemtap(5)AUTHORS
The SSSD upstream - https://github.com/SSSD/sssd/04/11/2023 | SSSD |