man pages section 5: Standards, Environments, and Macros

pam_ldap(5)

Name

pam_ldap– authentication and account management PAM module for LDAP

Synopsis

/usr/lib/security/pam_ldap.so.1

Description

The pam_ldap module implements pam_sm_authenticate(3PAM) and pam_sm_acct_mgmt(3PAM), the functions that provide functionality for the PAM authentication and account management stacks. The pam_ldap module ties the authentication and account management functionality to the functionality of the supporting LDAP server. For authentication, pam_ldap can authenticate the user directly to any LDAP directory server by using any supported authentication mechanism, such as DIGEST-MD5. However, the account management component of pam_ldap will work only with the Sun Java System Directory Server. The server's user account management must be properly configured before it can be used by pam_ldap. Refer to the Sun Java System Directory Server Administration Guide for information on how to configure user account management, including password and account lockout policy.

pam_ldap must be used in conjunction with the modules that support the UNIX authentication, password, and account management, which are pam_authtok_get(5), pam_passwd_auth(5), pam_unix_account(5), and pam_unix_auth(5). pam_ldap is designed to be stacked directly below these modules. If other modules are designed to be stacked in this manner, the modules can be stacked below the pam_ldap module. The Examples section shows how the UNIX modules are stacked with pam_ldap. When stacked together, the UNIX modules are used to control local accounts, such as root. pam_ldap is used to control network accounts, that is, LDAP users. For the stacks to work, pam_unix_auth, pam_unix_account, and pam_passwd_auth must be configured with the binding control flag and the server_policy option. This configuration allows local account override of a network account.

LDAP Authentication Module

The LDAP authentication module verifies the identity of a user. The pam_sm_authenticate(3PAM) function uses the password entered by the user to attempt to authenticate to the LDAP server. If successful, the user is authenticated. See NOTES for information on password prompting.

The authentication method used is either defined in the client profile , or the authentication method is configured by using the ldapclient(1M) command. To determine the authentication method to use, this module first attempts to use the authentication method that is defined, for service pam_ldap, for example, serviceAuthenticationMethod:pam_ldap:sasl/DIGEST-MD5. If no authentication method is defined, pam_ldap uses the default authentication method. If neither are set, the authentication fails. This module skips the configured authentication method if the authentication method is set to none.

The following options can be passed to the LDAP service module:

debug: syslog(3C) debugging information at LOG_DEBUG level.
nowarn: Turn off warning messages.

These options are case sensitive and must be used exactly as presented here.

LDAP Account Management Module

The LDAP account management module validates the user's account. The pam_sm_acct_mgmt(3PAM) function authenticates to the LDAP server to verify that the user's password has not expired, or that the user's account has not been locked. In the event that there is no user authentication token (PAM_AUTHTOK) available, the pam_sm_acct_mgmt(3PAM) function attempts to retrieve the user's account status without authenticating to the LDAP server as the user logging in. This procedure will succeed only if the LDAP server is Sun Java System Directory server 5.2 patch 4 or newer. The following options can be passed to the LDAP service module:

debug: syslog(3C) debugging information at LOG_DEBUG level.
nowarn: Turn off warning messages.

These options are case sensitive, and the options must be used exactly as presented here.

LDAP Password Management Module

LDAP password management is no longer supported by pam_ldap. Use pam_authtok_store(5) instead of pam_ldap for password change. pam_authtok_store(5) handles both the local and LDAP accounts and updates the passwords in all the repositories configured by nsswitch.conf(4).

Errors

The authentication service returns the following error codes:

PAM_SUCCESS: The uthentication was successful.
PAM_MAXTRIES: The maximum number of authentication attempts was exceeded.
PAM_AUTH_ERR: The authentication failed.
PAM_USER_UNKNOWN: No account is present for the user.
PAM_BUF_ERR: A memory buffer error occurred.
PAM_SYSTEM_ERR: A system error occurred.
PAM_IGNORE: The user's account was inactivated.

The account management service returns the following error codes:

PAM_SUCCESS: The user was allowed access to the account.
PAM_NEW_AUTHTOK_REQD: A new authentication token is required.
PAM_ACCT_EXPIRED: The user account has expired.
PAM_PERM_DENIED: The user was denied access to the account at this time.
PAM_USER_UNKNOWN: No account is present for the user.
PAM_BUF_ERROR: A memory buffer error occurred.
PAM_SYSTEM_ERR: A system error occurred.

Examples

Example 1 Using `pam_ldap` With Authentication

The following is a configuration for the login service when using pam_ldap. The service name login can be substituted for any other authentication service such as dtlogin or su. Lines that begin with the # symbol are comments and are ignored.

# Authentication management for login service is stacked.
# If pam_unix_auth succeeds, pam_ldap is not invoked.
# The control flag "binding" provides a local overriding
# remote (LDAP) control. The "server_policy" option is used
# to tell pam_unix_auth.so.1 to ignore the LDAP users.

login   auth requisite  pam_authtok_get.so.1
login   auth required   pam_dhkeys.so.1
login   auth required   pam_unix_cred.so.1
login   auth binding    pam_unix_auth.so.1 server_policy 
login   auth required   pam_ldap.so.1

Example 2 Using `pam_ldap` With Account Management

The following is a configuration for account management when using pam_ldap. Lines that begin with the # symbol are comments and are ignored.

# Account management for all services is stacked
# If pam_unix_account succeeds, pam_ldap is not invoked.
# The control flag "binding" provides a local overriding
# remote (LDAP) control. The "server_policy" option is used
# to tell pam_unix_account.so.1 to ignore the LDAP users.

other   account  requisite      pam_roles.so.1
other   account  binding        pam_unix_account.so.1 server_policy
other   account  required       pam_ldap.so.1

Example 3 Using `pam_authtok_store` With Password Management For Both Local and LDAP Accounts

The following is a configuration for password management when using pam_authtok_store. Lines that begin with the # symbol are comments and are ignored.

# Password management (authentication)
# The control flag "binding" provides a local overriding
# remote (LDAP) control. The server_policy option is used
# to tell pam_passwd_auth.so.1 to ignore the LDAP users.

passwd  auth binding  pam_passwd_auth.so.1 server_policy
passwd  auth required pam_ldap.so.1

# Password management (updates)
# This updates passwords stored both in the local /etc
# files and in the LDAP directory. The "server_policy"
# option is used to tell pam_authtok_store to
# follow the LDAP server's policy when updating
# passwords stored in the LDAP directory

other password required   pam_dhkeys.so.1
other password requisite  pam_authtok_get.so.1
other password requisite  pam_authtok_check.so.1
other password required   pam_authtok_store.so.1 server_policy

Files

/var/ldap/ldap_client_file /var/ldap/ldap_client_cred: The LDAP configuration files of the client. Do not manually modify these files, as these files might not be human readable. Use ldapclient(1M) to update these files.
/etc/pam.conf: PAM configuration file.

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving
MT-Level	MT-Safe with exceptions

Notes

The interfaces in libpam(3LIB) are MT-Safe only if each thread within the multi-threaded application uses its own PAM handle.

The previously supported use_first_pass and try_first_pass options are obsolete in this version, are no longer needed, can safely be removed from pam.conf(4), and are silently ignored. They might be removed in a future release. Password prompting must be provided for by stacking pam_authtok_get(5) before pam_ldap in the auth and password module stacks and pam_passwd_auth(5) in the passwd service auth stack (as described in the EXAMPLES section). The previously supported password update function is replaced in this release by the previously recommended use of pam_authtok_store with the server_policy option (as described in the EXAMPLES section).

The functions: pam_sm_setcred(3PAM), pam_sm_chauthtok(3PAM), pam_sm_open_session(3PAM), and pam_sm_close_session(3PAM) do nothing and return PAM_IGNORE in pam_ldap.

SunOS 5.10 Last Revised 21 Dec 2005