System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP)

For Clients That Use pam_ldap

In order for pam_ldap to work properly, the password and account lockout policy must be properly configured on the server. You can use the Directory Server Console or ldapmodify to configure the account management policy for the LDAP directory. For procedures and more information, see the “User Account Management” chapter in the Administration Guide for the version of Sun Java System Directory Server that you are using.

Note –

Previously, if you enabled pam_ldap account management, all users needed to provide a login password for authentication any time they logged in to the system. Therefore, nonpassword-based logins using tools such as rsh, rlogin, or ssh would fail.

Now, however, pam_ldap(5), when used with Sun Java System Directory Servers DS5.2p4 and newer releases, enables users to log in with rsh, rlogin, rcp and ssh without giving a password.

pam_ldap(5) is now modified to perform account management and retrieve the account status of users without authenticating to Directory Server as the user logging in. The new control to this on Directory Server is, which is enabled by default.

To modify this control for other than default, add Access Control Instructions (ACI) on Directory Server:

dn: oid=,cn=features,cn=config
objectClass: top
objectClass: directoryServerFeature
cn:Password Policy Account Usable Request Control
aci: (targetattr != "aci")(version 3.0; acl "Account Usable"; 
     allow (read, search, compare, proxy)
     (groupdn = "ldap:///cn=Administrators,cn=config");)
creatorsName: cn=server,cn=plugins,cn=config
modifiersName: cn=server,cn=plugins,cn=config

Passwords for proxy users should never be allowed to expire. If proxy passwords expire, clients using the proxy credential level cannot retrieve naming service information from the server. To ensure that proxy users have passwords that do not expire, modify the proxy accounts with the following script.

# ldapmodify -h ldapserver -D administrator DN \
-w administrator password <<EOF
dn: proxy user DN
DNchangetype: modify
replace: passwordexpirationtime
passwordexpirationtime: 20380119031407Z

Note –

pam_ldap account management relies on Sun Java System Directory Server to maintain and provide password aging and account expiration information for users. The directory server does not interpret the corresponding data from shadow entries to validate user accounts. pam_unix, however, examines the shadow data to determine if accounts are locked or if passwords are aged. Since the shadow data is not kept up to date by the LDAP naming services or the directory server, pam_unix should not grant access based on the shadow data. The shadow data is retrieved using the proxy identity. Therefore, do not allow proxy users to have read access to the userPassword attribute. Denying proxy users read access to userPassword prevents pam_unix from making an invalid account validation.