jsmith in the ldap.example.com domain and jsmith in the ldap.otherexample.com domain. SSSD allows requests using fully-qualified domain names, so requesting information for jsmith@ldap.example.com returns the proper user account. Specifying only the username returns the user for whichever domain comes first in the lookup order.
Tip
filter_users option, which excludes the specified users from being returned in a search.
Table 7.3. Identity Store and Authentication Type Combinations
| Identification Provider | Authentication Provider |
|---|---|
| LDAP | LDAP |
| LDAP | Kerberos |
| proxy | LDAP |
| proxy | Kerberos |
| proxy | proxy |
domains = LOCAL,Name [domain/Name] id_provider = type auth_provider = type provider_specific = value global = value
Table 7.4. General [domain] Configuration Parameters
| Parameter | Value Format | Description |
|---|---|---|
| id_provider | string | Specifies the data provider identity backend to use for this domain. The supported identity backends are:
|
| auth_provider | string | Sets the authentication provider used for the domain. The default value for this option is the value of id_provider. The supported authentication providers are ldap, ipa, krb5 (Kerberos), proxy, and none. |
| min_id,max_id | integer | Optional. Specifies the UID and GID range for the domain. If a domain contains entries that are outside that range, they are ignored. The default value for min_id is 1; the default value for max_id is 0, which is unlimited.
Important
The default min_id value is the same for all types of identity provider. If LDAP directories are using UID numbers that start at one, it could cause conflicts with users in the local /etc/passwd file. To avoid these conflicts, set min_id to 1000 or higher as possible.
|
| enumerate | Boolean | Optional. Specifies whether to list the users and groups of a domain. Enumeration means that the entire set of available users and groups on the remote source is cached on the local machine. When enumeration is disabled, users and groups are only cached as they are requested.
Warning
When enumeration is enabled, reinitializing a client results in a complete refresh of the entire set of available users and groups from the remote source. Similarly, when SSSD is connected to a new server, the entire set of available users and groups from the remote source is pulled and cached on the local machine. In a domain with a large number of clients connected to a remote source, this refresh process can harm the network performance because of frequent queries from the clients. If the set of available users and groups is large enough, it degrades client performance as well.
false, which disables enumeration. |
| cache_credentials | Boolean | Optional. Specifies whether to store user credentials in the local SSSD domain database cache. The default value for this parameter is false. Set this value to true for domains other than the LOCAL domain to enable offline authentication. |
| entry_cache_timeout | integer | Optional. Specifies how long, in seconds, SSSD should cache positive cache hits. A positive cache hit is a successful query. |
| use_fully_qualified_names | Boolean | Optional. Specifies whether requests to this domain require fully-qualified domain names. If set to true, all requests to this domain must use fully-qualified domain names. It also means that the output from the request displays the fully-qualified name. Restricting requests to fully-qualified user names allows SSSD to differentiate between domains with users with conflicting usernames.
If
use_fully_qualified_names is set to false, it is possible to use the fully-qualified name in the requests, but only the simplified version is displayed in the output.
SSSD can only parse names based on the domain name, not the realm name. The same name can be used for both domains and realms, however.
|
Note
Tip
sssd-ldap(5).
Table 7.5. LDAP Domain Configuration Parameters
| Parameter | Description |
|---|---|
| ldap_uri | Gives a comma-separated list of the URIs of the LDAP servers to which SSSD will connect. The list is given in order of preference, so the first server in the list is tried first. Listing additional servers provides failover protection. This can be detected from the DNS SRV records if it is not given. |
| ldap_search_base | Gives the base DN to use for performing LDAP user operations. |
| ldap_tls_reqcert | Specifies how to check for SSL server certificates in a TLS session. There are four options:
|
| ldap_tls_cacert | Gives the full path and file name to the file that contains the CA certificates for all of the CAs that SSSD recognizes. SSSD will accept any certificate issued by these CAs.
This uses the OpenLDAP system defaults if it is not given explicitly.
|
| ldap_referrals | Sets whether SSSD will use LDAP referrals, meaning forwarding queries from one LDAP database to another. SSSD supports database-level and subtree referrals. For referrals within the same LDAP server, SSSD will adjust the DN of the entry being queried. For referrals that go to different LDAP servers, SSSD does an exact match on the DN. Setting this value to true enables referrals; this is the default. |
| ldap_schema | Sets what version of schema to use when searching for user entries. This can be either rfc2307 or rfc2307bis. The default is rfc2307.
In RFC 2307, group objects use a multi-valued attribute,
memberuid, which lists the names of the users that belong to that group. In RFC 2307bis, group objects use the member attribute, which contains the full distinguished name (DN) of a user or group entry. RFC 2307bis allows nested groups usning the member attribute. Because these different schema use different definitions for group membership, using the wrong LDAP schema with SSSD can affect both viewing and managing network resources, even if the appropriate permissions are in place.
For example, with RFC 2307bis, all groups are returned when using nested groups or primary/secondary groups.
$ id uid=500(myserver) gid=500(myserver) groups=500(myserver),510(myothergroup)
If SSSD is using RFC 2307 schema, only the primary group is returned.
This setting only affects how SSSD determines the group members. It does not change the actual user data.
|
| ldap_search_timeout | Sets the time, in seconds, that LDAP searches are allowed to run before they are canceled and cached results are returned. This defaults to five when the enumerate value is false and defaults to 30 when enumerate is true.
When an LDAP search times out, SSSD automatically switches to offline mode.
|
| ldap_network_timeout | Sets the time, in seconds, SSSD attempts to poll an LDAP server after a connection attempt fails. The default is six seconds. |
| ldap_opt_timeout | Sets the time, in seconds, to wait before aborting synchronous LDAP operations if no response is received from the server. This option also controls the timeout when communicating with the KDC in case of a SASL bind. The default is five seconds. |
Note
sssd.conf file. For example:
domains = LOCAL,LDAP1,AD,PROXYNIS
Example 7.1. A Basic LDAP Domain Configuration
ldap_uri option:
# An LDAP domain [domain/LDAP] enumerate = false cache_credentials = true id_provider = ldap auth_provider = ldap ldap_uri = ldaps://ldap.example.com:636 ldap_search_base = dc=example,dc=com
ldap_id_use_start_tls option to use Start TLS and then ldap_tls_cacert to identify the CA certificate which issued the SSL server certificates.
# An LDAP domain [domain/LDAP] enumerate = false cache_credentials = true id_provider = ldap auth_provider = ldap ldap_uri = ldap://ldap.example.com ldap_search_base = dc=example,dc=com ldap_id_use_start_tls = true ldap_tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt
Note
authconfig, set the Linux client to use Active Directory as its LDAP identity provider. For example:
authconfig --enableldap --enableldapauth --ldapserver=ldap://ad.example.com:389 --enablekrb5 --krb5realm AD-REALM.EXAMPLE.COM --krb5kdc ad-kdc.example.com:88 --krb5adminserver ad-kdc.example.com:749 --update
authconfig command is described in Section 7.1, “Configuring System Authentication”.
ad.example.com.
rhel-server, and click .
rhel-server object, and select .
C:\> setspn -A host/rhel-server.example.com@AD-REALM.EXAMPLE.COM rhel-server
Registering ServicePrincipalNames for CN=rhel server,CN=Computers,DC=ad,DC=example,DC=com
host/rhel server.example.com@AD-REALM.EXAMPLE.COM
Updated object
C:\> setspn -L rhel-server
Registered ServicePrincipalNames for CN=rhel server,CN=Computers,DC=ad,DC=example,DC=com:
host/rhel server.example.com@AD-REALM.EXAMPLE.COM
C:\> ktpass /princ host/rhel-server.example.com@AD-REALM.EXAMPLE.COM /out rhel-server.keytab /crypto all /ptype KRB5_NT_PRINCIPAL -desonly /mapuser AD\rhel-server$ +rndPass
Targeting domain controller:
ad.example.com
Using legacy password setting method
Successfully mapped host/rhel server.redhat.com
... 8< .../etc/krb5.keytab.
[root@rhel-server ~]# chown root:root /etc/krb5.keytab [root@rhel-server ~]# chmod 0600 /etc/krb5.keytab
[root@rhel-server ~]# restorecon /etc/krb5.keytab
[root@rhel-server ~]# kinit -k -t /etc/krb5.keytab host/rhel-server.example.com@AD-REALM.EXAMPLE.COM
/bin/bash
/home/aduser
unixusers
Example 7.2. An Active Directory 2008 Domain
[root@rhel-server ~]# vim /etc/sssd/sssd.conf [sssd] config_file_version = 2 domains = ad.example.com services = nss, pam [nss] [pam] [domain/ad.example.com] cache_credentials = true enumerate = false id_provider = ldap auth_provider = krb5 chpass_provider = krb5 access_provider = ldap ldap_sasl_mech = GSSAPI ldap_sasl_authid = host/rhel-server.example.com@AD-REALM.EXAMPLE.COM ldap_schema = rfc2307bis ldap_user_search_base = ou=user accounts,dc=ad,dc=example,dc=com ldap_user_object_class = user ldap_user_home_directory = unixHomeDirectory ldap_user_principal = userPrincipalName ldap_user_name = sAMAccountName ldap_group_search_base = ou=groups,dc=ad,dc=example,dc=com ldap_group_object_class = group ldap_access_order = expire ldap_account_expire_policy = ad ldap_force_upper_case_realm = true ldap_disable_referrals = true #krb5_server = server.ad.example.com krb5_realm = AD-REALM.EXAMPLE.COM
sssd-ldap(5).
[root@rhel-server ~]# service sssd restart
ldap_uri option instead of the server name may cause the TLS/SSL connection to fail. TLS/SSL certificates contain the server name, not the IP address. However, the subject alternative name field in the certificate can be used to include the IP address of the server, which allows a successful secure connection using an IP address.
-signkey) is the key of the issuer of whatever CA originally issued the certificate. If this is done by an external CA, it requires a separate PEM file; if the certificate is self-signed, then this is the certificate itself. For example:
openssl x509 -x509toreq -in old_cert.pem -out req.pem -signkey key.pem
openssl x509 -x509toreq -in old_cert.pem -out req.pem -signkey old_cert.pem
/etc/pki/tls/openssl.cnf configuration file to include the server's IP address under the [ v3_ca ] section:
subjectAltName = IP:10.0.0.10
openssl x509 -req -in req.pem -out new_cert.pem -extfile ./openssl.cnf -extensions v3_ca -signkey old_cert.pem
-extensions option sets which extensions to use with the certificate. For this, it should be v3_ca to load the appropriate section.
old_cert.pem file into the new_cert.pem file to keep all relevant information in one file.
nss-utils package, note that certutil supports DNS subject alternative names for certificate creation only.
Note
krb5_kpasswd option to specify where the password changing service is running or if it is running on a non-default port. If the krb5_kpasswd option is not defined, SSSD tries to use the Kerberos KDC to change the password.
sssd-krb5(5) man page has more information about Kerberos configuration options.
Example 7.3. Basic Kerberos Authentication
# A domain with identities provided by LDAP and authentication by Kerberos [domain/KRBDOMAIN] enumerate = false id_provider = ldap chpass_provider = krb5 ldap_uri = ldap://ldap.example.com ldap_search_base = dc=example,dc=com ldap-tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt auth_provider = krb5 krb5_server = 192.168.1.1, kerberos.example.com krb5_realm = EXAMPLE.COM krb5_kpasswd = kerberos.admin.example.com krb5_auth_timeout = 15
Table 7.6. Kerberos Authentication Configuration Parameters
| Parameter | Description |
|---|---|
| chpass_provider | Specifies which service to use for password change operations. This is assumed to be the same as the authentication provider. To use Kerberos, set this to krb5. |
| krb5_server | Gives a comma-separated list of IP addresses or hostnames of Kerberos servers to which SSSD will connect. The list is given in order of preference, so the first server in the list is tried first. Listing additional servers provides failover protection.
When using service discovery for KDC or kpasswd servers, SSSD first searches for DNS entries that specify UDP as the connection protocol, and then falls back to TCP.
|
| krb5_realm | Identies the Kerberos realm served by the KDC. |
| krb5_lifetime | Requests a Kerberos ticket with the specified lifetime in seconds (s), minutes (m), hours (h) or days (d). |
| krb5_renewable_lifetime | Requests a renewable Kerberos ticket with a total lifetime that is specified in seconds (s), minutes (m), hours (h) or days (d). |
| krb5_renew_interval | Sets the time, in seconds, for SSSD to check if tickets should be renewed. Tickets are renewed automatically once they exceed half their lifetime. If this option is missing or set to zero, then automatic ticket renewal is disabled. |
| krb5_store_password_if_offline | Sets whether to store user passwords if the Kerberos authentication provider is offline, and then to use that cache to request tickets when the provider is back online. The default is false, which does not store passwords. |
| krb5_kpasswd | Lists alternate Kerberos kadmin servers to use if the change password service is not running on the KDC. |
| krb5_ccname_template | Gives the directory to use to store the user's credential cache. This can be templatized, and the following tokens are supported:
krb5_ccname_template = FILE:%d/krb5cc_%U_XXXXXX |
| krb5_ccachedir | Specifies the directory to store credential caches. This can be templatized, using the same tokens as krb5_ccname_template, except for %d and %P. If %u, %U, %p, or %h are used, then SSSD creates a private directory for each user; otherwise, it creates a public directory. |
| krb5_auth_timeout | Gives the time, in seconds, before an online authentication or change password request is aborted. If possible, the authentication request is continued offline. The default is 15 seconds. |
Table 7.7. Proxy Domain Configuration Parameters
| Parameter | Description |
|---|---|
| proxy_pam_target | Specifies the target to which PAM must proxy as an authentication provider. The PAM target is a file containing PAM stack information in the default PAM directory, /etc/pam.d/.
This is used to proxy an authentication provider.
Important
Ensure that the proxy PAM stack does not recursively include pam_sss.so.
|
| proxy_lib_name | Specifies which existing NSS library to proxy identity requests through.
This is used to proxy an identity provider.
|
Example 7.4. Proxy Identity and Kerberos Authentication
proxy_lib_name parameter. This library can be anything as long as it is compatible with the given authentication service. For a Kerberos authentication provider, it must be a Kerberos-compatible library, like NIS.
[domain/PROXY_KRB5] auth_provider = krb5 krb5_server = 192.168.1.1 krb5_realm = EXAMPLE.COM id_provider = proxy proxy_lib_name = nis enumerate = true cache_credentials = true
Example 7.5. LDAP Identity and Proxy Authentication
proxy_pam_target parameter. This library must be a PAM module that is compatible with the given identity provider. For example, this uses a PAM fingerprint module with LDAP:
[domain/LDAP_PROXY] id_provider = ldap ldap_uri = ldap://example.com ldap_search_base = dc=example,dc=com auth_provider = proxy proxy_pam_target = sssdpamproxy enumerate = true cache_credentials = true
sssdpamproxy, so create a /etc/pam.d/sssdpamproxy file and load the PAM/LDAP modules:
auth required pam_frprint.so account required pam_frprint.so password required pam_frprint.so session required pam_frprint.so
Example 7.6. Proxy Identity and Authentication
proxy_pam_target for the authentication PAM module and proxy_lib_name for the service, like NIS or LDAP.
[domain/PROXY_PROXY] auth_provider = proxy id_provider = proxy proxy_lib_name = ldap proxy_pam_target = sssdproxyldap enumerate = true cache_credentials = true
/etc/pam.d/sssdproxyldap file which requires the pam_ldap.so module:
auth required pam_ldap.so account required pam_ldap.so password required pam_ldap.so session required pam_ldap.so
nss-pam-ldap package is installed.
[root@server ~]# yum install nss-pam-ldap
/etc/nslcd.conf file, the configuration file for the LDAP name service daemon, to contain the information for the LDAP directory:
uid nslcd gid ldap uri ldaps://ldap.example.com:636 base dc=example,dc=com ssl on tls_cacertdir /etc/openldap/cacerts