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From John Holman <>
Subject {PATCH] Enhanced JNDI realm
Date Fri, 01 Feb 2002 21:56:44 GMT

I've attached a patch to enhance the current JNDI realm implementation. 
This includes three features that have been requested a number of times and 
appear in the draft functional specification:

** the realm can authenticate by binding to the directory as the user. This 
mode of operation is usually to be preferred unless HTTP digest 
authentication is required. The realm will automatically authenticate in 
this way if the "userPassword" configuration attribute is not specified. 
The "connectionName" and "connectPassword" properties are used
when searching the directory or retrieving role information. In this mode, 
anonymous authentication is often sufficient, in which case these need not 
be specified.

** the realm can search the directory for the user's entry. It will do this 
if the "userPattern" configuration attribute is not specified.

Three new configuration parameters control the search for the user's 
directory entry:

userSearch - a pattern specifying the LDAP search filter for selecting 
users. Use {0} to substitute in the username.

userBase - the base element for user searches. If not specified the top 
level element in the directory context will be used.

useSubtree - set to true if you want user searches to search subtrees of 
the element selected by userBase. The default value of false causes only 
the top level element to be searched.

** the realm can combine roles held as the values of an attribute in the 
user's entry with those retrieved from a search for roles. The search for 
roles takes place as before. If the roleSearch configuration attribute is 
not specified the realm will look only in the user's entry for roles.

This feature uses one new configuration attribute:

userRoleName - the name of an attribute in the user's entry containing the 
names of roles. If not specified the directory is searched for roles as before.

Note that the new configuration interface is backwards compatible with the 
current JNDIRealm. For existing users the realm will behave just as it did 
before - no configuration changes are required. The existing documentation 
is still accurate about the subset of functionality it describes.

Here is a sample realm configuration that demonstrates all three new 
features. It is assumed that an anonymous bind is sufficient to search the 
directory for the user
and retrieve the role information. The user is found by searching the 
directory and authenticated by binding to the directory with the 
credentials presented by the user. Role names are contained both in the 
"memberOf" attribute of the user's own directory entry and in the "cn" 
attribute of group entries to which the user belongs

       <Realm className="org.apache.catalina.realm.JNDIRealm"

I've not addressed issues of connection management etc in this patch, 
though there is certainly room for improvement (context pooling etc). In a 
previous message you mentioned leveraging the "global JNDI resources" 
capabilities for that, and Tony Danbura has also expressed an interest in 
this area. However the enhancements in this patch are independent of that 
issue, and should not complicate it. In particular, note that the "bind 
mode" functionality is implemented in a way that still uses a single 
directory context that can be returned to the pool. This is achieved by 
changing the security environment of the context before and after binding, 
rather than creating a different context for the bind. With an LDAP v3 
server this should be an efficient approach since the underlying connection 
to the directory server does not change. An LDAP v2 server must create a 
new connection for each bind operation, so context pooling will not be so 
effective, but that does not affect the logic.

I'd be very grateful if you would take a look at this patch and hopefully 
submit it. If it is accepted I promise I'll update the documentation to 
cover the new features!

Thanks, John.


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