Chapter 12. Managing SASL

NOTE

GSS-APIand, thus, Kerberos are only supported on platforms that have GSS-APIsupport. To use GSS-API, it may be necessary to install the Kerberos client libraries; any required Kerberos libraries will be available through the operating system vendor.

CRAM-MD5, DIGEST-MD5, and GSS-APIare shared secret mechanisms. The server challenges the client attempting to bind with a secret, such as a password, that depends on the mechanism. The user sends back the response required by the mechanism.

NOTE

DIGEST-MD5requires clear text passwords. The Directory Server requires the clear text password in order to generate the shared secret. Passwords already stored as a hashed value, such as SHA1 cannot be used with DIGEST-MD5.

2. SASL Identity Mapping

When processing a SASL bind request, the server matches, or maps, the SASL authentication ID used to authenticate to the Directory Server with an LDAP entry stored within the server. When using Kerberos, the SASL user ID usually has the format userid@REALM, such as scarter@EXAMPLE.COM. This ID must be converted into the DN of the user's Directory Server entry, such as uid=scarter,ou=people,dc=example,dc=com.

If the authentication ID clearly corresponds to the LDAP entry for a person, it is possible to configure the Directory Server to map the authentication ID automatically to the entry DN. Directory Server has some preconfigured default maps which handle most common configurations, and customized maps can be created. During a bind attempt, the first matching mapping rule is applied. If only one user identity is returned, the bind is successful; if none or more than one are returned, then the bind fails. Red Hat recommends configuring SASL maps so that only one mapping rule matches the authentication string.

NOTE

SASL proxy authorization is not supported in Directory Server; therefore, Directory Server ignores any SASL authzid value supplied by the client.

SASL is configured by entries under a container entry:

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HP UX Red Hat Direry Server Software manual Sasl Identity Mapping, Managing Sasl