Java LDAP - Determine if user in a given group?
We logon users to Active Directory via LDAP using the Java LDAP API. We want to enhance our logon functionality to further check if the user is in a given AD group. Does anyone know how to do this?
Current code:
import javax.naming.*;
import javax.naming.ldap.*;
LdapContext ctx = null;
Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY,"com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.SECURITY_AUTHENTICATION,"simple");
env.put(Context.PROVIDER_URL, Config.get("ldap-url"));
try {
Control[] connCtls = new Control[] {new FastBindConnectionControl()};
ctx = new InitialLdapContext(env, connCtls);
ctx.addToEnvironment(Context.SECURITY_PRINCIPAL, "DOMAIN\\" + username);
ctx.addToEnvironment(Context.SECURITY_CREDENTIALS, password);
ctx.reconnect(connCtls);
/* TODO: Only return true if user is in group "ABC" */
return true; //User authenticated
} catch (Exception e) {
return false; //User could NOT be authenticated
} finally {
...
}
Update: See the solution below.
Answer
We solved this with the class below. Just call the authenticate method:
import java.text.MessageFormat;
import java.util.*;
import javax.naming.*;
import org.apache.log4j.Level;
public class LdapGroupAuthenticator {
public static final String DISTINGUISHED_NAME = "distinguishedName";
public static final String CN = "cn";
public static final String MEMBER = "member";
public static final String MEMBER_OF = "memberOf";
public static final String SEARCH_BY_SAM_ACCOUNT_NAME = "(SAMAccountName={0})";
public static final String SEARCH_GROUP_BY_GROUP_CN = "(&(objectCategory=group)(cn={0}))";
/*
* Prepares and returns CN that can be used for AD query
* e.g. Converts "CN=**Dev - Test Group" to "**Dev - Test Group"
* Converts CN=**Dev - Test Group,OU=Distribution Lists,DC=DOMAIN,DC=com to "**Dev - Test Group"
*/
public static String getCN(String cnName) {
if (cnName != null && cnName.toUpperCase().startsWith("CN=")) {
cnName = cnName.substring(3);
}
int position = cnName.indexOf(',');
if (position == -1) {
return cnName;
} else {
return cnName.substring(0, position);
}
}
public static boolean isSame(String target, String candidate) {
if (target != null && target.equalsIgnoreCase(candidate)) {
return true;
}
return false;
}
public static boolean authenticate(String domain, String username, String password) {
Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY,"com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldap://1.2.3.4:389");
env.put(Context.SECURITY_AUTHENTICATION, "simple");
env.put(Context.SECURITY_PRINCIPAL, domain + "\\" + username);
env.put(Context.SECURITY_CREDENTIALS, password);
DirContext ctx = null;
String defaultSearchBase = "DC=DOMAIN,DC=com";
String groupDistinguishedName = "DN=CN=DLS-APP-MyAdmin-C,OU=DLS File Permissions,DC=DOMAIN,DC=com";
try {
ctx = new InitialDirContext(env);
// userName is SAMAccountName
SearchResult sr = executeSearchSingleResult(ctx, SearchControls.SUBTREE_SCOPE, defaultSearchBase,
MessageFormat.format( SEARCH_BY_SAM_ACCOUNT_NAME, new Object[] {username}),
new String[] {DISTINGUISHED_NAME, CN, MEMBER_OF}
);
String groupCN = getCN(groupDistinguishedName);
HashMap processedUserGroups = new HashMap();
HashMap unProcessedUserGroups = new HashMap();
// Look for and process memberOf
Attribute memberOf = sr.getAttributes().get(MEMBER_OF);
if (memberOf != null) {
for ( Enumeration e1 = memberOf.getAll() ; e1.hasMoreElements() ; ) {
String unprocessedGroupDN = e1.nextElement().toString();
String unprocessedGroupCN = getCN(unprocessedGroupDN);
// Quick check for direct membership
if (isSame (groupCN, unprocessedGroupCN) && isSame (groupDistinguishedName, unprocessedGroupDN)) {
Log.info(username + " is authorized.");
return true;
} else {
unProcessedUserGroups.put(unprocessedGroupDN, unprocessedGroupCN);
}
}
if (userMemberOf(ctx, defaultSearchBase, processedUserGroups, unProcessedUserGroups, groupCN, groupDistinguishedName)) {
Log.info(username + " is authorized.");
return true;
}
}
Log.info(username + " is NOT authorized.");
return false;
} catch (AuthenticationException e) {
Log.info(username + " is NOT authenticated");
return false;
} catch (NamingException e) {
throw new SystemException(e);
} finally {
if (ctx != null) {
try {
ctx.close();
} catch (NamingException e) {
throw new SystemException(e);
}
}
}
}
public static boolean userMemberOf(DirContext ctx, String searchBase, HashMap processedUserGroups, HashMap unProcessedUserGroups, String groupCN, String groupDistinguishedName) throws NamingException {
HashMap newUnProcessedGroups = new HashMap();
for (Iterator entry = unProcessedUserGroups.keySet().iterator(); entry.hasNext();) {
String unprocessedGroupDistinguishedName = (String) entry.next();
String unprocessedGroupCN = (String)unProcessedUserGroups.get(unprocessedGroupDistinguishedName);
if ( processedUserGroups.get(unprocessedGroupDistinguishedName) != null) {
Log.info("Found : " + unprocessedGroupDistinguishedName +" in processedGroups. skipping further processing of it..." );
// We already traversed this.
continue;
}
if (isSame (groupCN, unprocessedGroupCN) && isSame (groupDistinguishedName, unprocessedGroupDistinguishedName)) {
Log.info("Found Match DistinguishedName : " + unprocessedGroupDistinguishedName +", CN : " + unprocessedGroupCN );
return true;
}
}
for (Iterator entry = unProcessedUserGroups.keySet().iterator(); entry.hasNext();) {
String unprocessedGroupDistinguishedName = (String) entry.next();
String unprocessedGroupCN = (String)unProcessedUserGroups.get(unprocessedGroupDistinguishedName);
processedUserGroups.put(unprocessedGroupDistinguishedName, unprocessedGroupCN);
// Fetch Groups in unprocessedGroupCN and put them in newUnProcessedGroups
NamingEnumeration ns = executeSearch(ctx, SearchControls.SUBTREE_SCOPE, searchBase,
MessageFormat.format( SEARCH_GROUP_BY_GROUP_CN, new Object[] {unprocessedGroupCN}),
new String[] {CN, DISTINGUISHED_NAME, MEMBER_OF});
// Loop through the search results
while (ns.hasMoreElements()) {
SearchResult sr = (SearchResult) ns.next();
// Make sure we're looking at correct distinguishedName, because we're querying by CN
String userDistinguishedName = sr.getAttributes().get(DISTINGUISHED_NAME).get().toString();
if (!isSame(unprocessedGroupDistinguishedName, userDistinguishedName)) {
Log.info("Processing CN : " + unprocessedGroupCN + ", DN : " + unprocessedGroupDistinguishedName +", Got DN : " + userDistinguishedName +", Ignoring...");
continue;
}
Log.info("Processing for memberOf CN : " + unprocessedGroupCN + ", DN : " + unprocessedGroupDistinguishedName);
// Look for and process memberOf
Attribute memberOf = sr.getAttributes().get(MEMBER_OF);
if (memberOf != null) {
for ( Enumeration e1 = memberOf.getAll() ; e1.hasMoreElements() ; ) {
String unprocessedChildGroupDN = e1.nextElement().toString();
String unprocessedChildGroupCN = getCN(unprocessedChildGroupDN);
Log.info("Adding to List of un-processed groups : " + unprocessedChildGroupDN +", CN : " + unprocessedChildGroupCN);
newUnProcessedGroups.put(unprocessedChildGroupDN, unprocessedChildGroupCN);
}
}
}
}
if (newUnProcessedGroups.size() == 0) {
Log.info("newUnProcessedGroups.size() is 0. returning false...");
return false;
}
// process unProcessedUserGroups
return userMemberOf(ctx, searchBase, processedUserGroups, newUnProcessedGroups, groupCN, groupDistinguishedName);
}
private static NamingEnumeration executeSearch(DirContext ctx, int searchScope, String searchBase, String searchFilter, String[] attributes) throws NamingException {
// Create the search controls
SearchControls searchCtls = new SearchControls();
// Specify the attributes to return
if (attributes != null) {
searchCtls.setReturningAttributes(attributes);
}
// Specify the search scope
searchCtls.setSearchScope(searchScope);
// Search for objects using the filter
NamingEnumeration result = ctx.search(searchBase, searchFilter,searchCtls);
return result;
}
private static SearchResult executeSearchSingleResult(DirContext ctx, int searchScope, String searchBase, String searchFilter, String[] attributes) throws NamingException {
NamingEnumeration result = executeSearch(ctx, searchScope, searchBase, searchFilter, attributes);
SearchResult sr = null;
// Loop through the search results
while (result.hasMoreElements()) {
sr = (SearchResult) result.next();
break;
}
return sr;
}
}