/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.security;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import javax.naming.CommunicationException;
import javax.naming.Context;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
import javax.naming.directory.SearchControls;
import javax.naming.directory.SearchResult;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
/**
* An implementation of {@link GroupMappingServiceProvider} which
* connects directly to an LDAP server for determining group membership.
*
* This provider should be used only if it is necessary to map users to
* groups that reside exclusively in an Active Directory or LDAP installation.
* The common case for a Hadoop installation will be that LDAP users and groups
* materialized on the Unix servers, and for an installation like that,
* ShellBasedUnixGroupsMapping is preferred. However, in cases where
* those users and groups aren't materialized in Unix, but need to be used for
* access control, this class may be used to communicate directly with the LDAP
* server.
*
* It is important to note that resolving group mappings will incur network
* traffic, and may cause degraded performance, although user-group mappings
* will be cached via the infrastructure provided by {@link Groups}.
*
* This implementation does not support configurable search limits. If a filter
* is used for searching users or groups which returns more results than are
* allowed by the server, an exception will be thrown.
*
* The implementation also does not attempt to resolve group hierarchies. In
* order to be considered a member of a group, the user must be an explicit
* member in LDAP.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class LdapGroupsMapping
implements GroupMappingServiceProvider, Configurable {
public static final String LDAP_CONFIG_PREFIX = "hadoop.security.group.mapping.ldap";
/*
* URL of the LDAP server
*/
public static final String LDAP_URL_KEY = LDAP_CONFIG_PREFIX + ".url";
public static final String LDAP_URL_DEFAULT = "";
/*
* Should SSL be used to connect to the server
*/
public static final String LDAP_USE_SSL_KEY = LDAP_CONFIG_PREFIX + ".ssl";
public static final Boolean LDAP_USE_SSL_DEFAULT = false;
/*
* File path to the location of the SSL keystore to use
*/
public static final String LDAP_KEYSTORE_KEY = LDAP_CONFIG_PREFIX + ".ssl.keystore";
public static final String LDAP_KEYSTORE_DEFAULT = "";
/*
* Password for the keystore
*/
public static final String LDAP_KEYSTORE_PASSWORD_KEY = LDAP_CONFIG_PREFIX + ".ssl.keystore.password";
public static final String LDAP_KEYSTORE_PASSWORD_DEFAULT = "";
public static final String LDAP_KEYSTORE_PASSWORD_FILE_KEY = LDAP_KEYSTORE_PASSWORD_KEY + ".file";
public static final String LDAP_KEYSTORE_PASSWORD_FILE_DEFAULT = "";
/*
* User to bind to the LDAP server with
*/
public static final String BIND_USER_KEY = LDAP_CONFIG_PREFIX + ".bind.user";
public static final String BIND_USER_DEFAULT = "";
/*
* Password for the bind user
*/
public static final String BIND_PASSWORD_KEY = LDAP_CONFIG_PREFIX + ".bind.password";
public static final String BIND_PASSWORD_DEFAULT = "";
public static final String BIND_PASSWORD_FILE_KEY = BIND_PASSWORD_KEY + ".file";
public static final String BIND_PASSWORD_FILE_DEFAULT = "";
/*
* Base distinguished name to use for searches
*/
public static final String BASE_DN_KEY = LDAP_CONFIG_PREFIX + ".base";
public static final String BASE_DN_DEFAULT = "";
/*
* Any additional filters to apply when searching for users
*/
public static final String USER_SEARCH_FILTER_KEY = LDAP_CONFIG_PREFIX + ".search.filter.user";
public static final String USER_SEARCH_FILTER_DEFAULT = "(&(objectClass=user)(sAMAccountName={0}))";
/*
* Any additional filters to apply when finding relevant groups
*/
public static final String GROUP_SEARCH_FILTER_KEY = LDAP_CONFIG_PREFIX + ".search.filter.group";
public static final String GROUP_SEARCH_FILTER_DEFAULT = "(objectClass=group)";
/*
* LDAP attribute to use for determining group membership
*/
public static final String GROUP_MEMBERSHIP_ATTR_KEY = LDAP_CONFIG_PREFIX + ".search.attr.member";
public static final String GROUP_MEMBERSHIP_ATTR_DEFAULT = "member";
/*
* LDAP attribute to use for identifying a group's name
*/
public static final String GROUP_NAME_ATTR_KEY = LDAP_CONFIG_PREFIX + ".search.attr.group.name";
public static final String GROUP_NAME_ATTR_DEFAULT = "cn";
/*
* LDAP {@link SearchControls} attribute to set the time limit
* for an invoked directory search. Prevents infinite wait cases.
*/
public static final String DIRECTORY_SEARCH_TIMEOUT =
LDAP_CONFIG_PREFIX + ".directory.search.timeout";
public static final int DIRECTORY_SEARCH_TIMEOUT_DEFAULT = 10000; // 10s
private static final Log LOG = LogFactory.getLog(LdapGroupsMapping.class);
private static final SearchControls SEARCH_CONTROLS = new SearchControls();
static {
SEARCH_CONTROLS.setSearchScope(SearchControls.SUBTREE_SCOPE);
}
private DirContext ctx;
private Configuration conf;
private String ldapUrl;
private boolean useSsl;
private String keystore;
private String keystorePass;
private String bindUser;
private String bindPassword;
private String baseDN;
private String groupSearchFilter;
private String userSearchFilter;
private String groupMemberAttr;
private String groupNameAttr;
public static int RECONNECT_RETRY_COUNT = 3;
/**
* Returns list of groups for a user.
*
* The LdapCtx which underlies the DirContext object is not thread-safe, so
* we need to block around this whole method. The caching infrastructure will
* ensure that performance stays in an acceptable range.
*
* @param user get groups for this user
* @return list of groups for a given user
*/
@Override
public synchronized List<String> getGroups(String user) throws IOException {
List<String> emptyResults = new ArrayList<String>();
/*
* Normal garbage collection takes care of removing Context instances when they are no longer in use.
* Connections used by Context instances being garbage collected will be closed automatically.
* So in case connection is closed and gets CommunicationException, retry some times with new new DirContext/connection.
*/
try {
return doGetGroups(user);
} catch (CommunicationException e) {
LOG.warn("Connection is closed, will try to reconnect");
} catch (NamingException e) {
LOG.warn("Exception trying to get groups for user " + user, e);
return emptyResults;
}
int retryCount = 0;
while (retryCount ++ < RECONNECT_RETRY_COUNT) {
//reset ctx so that new DirContext can be created with new connection
this.ctx = null;
try {
return doGetGroups(user);
} catch (CommunicationException e) {
LOG.warn("Connection being closed, reconnecting failed, retryCount = " + retryCount);
} catch (NamingException e) {
LOG.warn("Exception trying to get groups for user " + user, e);
return emptyResults;
}
}
return emptyResults;
}
List<String> doGetGroups(String user) throws NamingException {
List<String> groups = new ArrayList<String>();
DirContext ctx = getDirContext();
// Search for the user. We'll only ever need to look at the first result
NamingEnumeration<SearchResult> results = ctx.search(baseDN,
userSearchFilter,
new Object[]{user},
SEARCH_CONTROLS);
if (results.hasMoreElements()) {
SearchResult result = results.nextElement();
String userDn = result.getNameInNamespace();
NamingEnumeration<SearchResult> groupResults =
ctx.search(baseDN,
"(&" + groupSearchFilter + "(" + groupMemberAttr + "={0}))",
new Object[]{userDn},
SEARCH_CONTROLS);
while (groupResults.hasMoreElements()) {
SearchResult groupResult = groupResults.nextElement();
Attribute groupName = groupResult.getAttributes().get(groupNameAttr);
groups.add(groupName.get().toString());
}
}
return groups;
}
@SuppressWarnings("deprecation")
DirContext getDirContext() throws NamingException {
if (ctx == null) {
// Set up the initial environment for LDAP connectivity
Hashtable<String, String> env = new Hashtable<String, String>();
env.put(Context.INITIAL_CONTEXT_FACTORY,
com.sun.jndi.ldap.LdapCtxFactory.class.getName());
env.put(Context.PROVIDER_URL, ldapUrl);
env.put(Context.SECURITY_AUTHENTICATION, "simple");
// Set up SSL security, if necessary
if (useSsl) {
env.put(Context.SECURITY_PROTOCOL, "ssl");
System.setProperty("javax.net.ssl.keyStore", keystore);
System.setProperty("javax.net.ssl.keyStorePassword", keystorePass);
}
env.put(Context.SECURITY_PRINCIPAL, bindUser);
env.put(Context.SECURITY_CREDENTIALS, bindPassword);
ctx = new InitialDirContext(env);
}
return ctx;
}
/**
* Caches groups, no need to do that for this provider
*/
@Override
public void cacheGroupsRefresh() throws IOException {
// does nothing in this provider of user to groups mapping
}
/**
* Adds groups to cache, no need to do that for this provider
*
* @param groups unused
*/
@Override
public void cacheGroupsAdd(List<String> groups) throws IOException {
// does nothing in this provider of user to groups mapping
}
@Override
public synchronized Configuration getConf() {
return conf;
}
@Override
public synchronized void setConf(Configuration conf) {
ldapUrl = conf.get(LDAP_URL_KEY, LDAP_URL_DEFAULT);
if (ldapUrl == null || ldapUrl.isEmpty()) {
throw new RuntimeException("LDAP URL is not configured");
}
useSsl = conf.getBoolean(LDAP_USE_SSL_KEY, LDAP_USE_SSL_DEFAULT);
keystore = conf.get(LDAP_KEYSTORE_KEY, LDAP_KEYSTORE_DEFAULT);
keystorePass =
conf.get(LDAP_KEYSTORE_PASSWORD_KEY, LDAP_KEYSTORE_PASSWORD_DEFAULT);
if (keystorePass.isEmpty()) {
keystorePass = extractPassword(
conf.get(LDAP_KEYSTORE_PASSWORD_KEY, LDAP_KEYSTORE_PASSWORD_DEFAULT));
}
bindUser = conf.get(BIND_USER_KEY, BIND_USER_DEFAULT);
bindPassword = conf.get(BIND_PASSWORD_KEY, BIND_PASSWORD_DEFAULT);
if (bindPassword.isEmpty()) {
bindPassword = extractPassword(
conf.get(BIND_PASSWORD_FILE_KEY, BIND_PASSWORD_FILE_DEFAULT));
}
baseDN = conf.get(BASE_DN_KEY, BASE_DN_DEFAULT);
groupSearchFilter =
conf.get(GROUP_SEARCH_FILTER_KEY, GROUP_SEARCH_FILTER_DEFAULT);
userSearchFilter =
conf.get(USER_SEARCH_FILTER_KEY, USER_SEARCH_FILTER_DEFAULT);
groupMemberAttr =
conf.get(GROUP_MEMBERSHIP_ATTR_KEY, GROUP_MEMBERSHIP_ATTR_DEFAULT);
groupNameAttr =
conf.get(GROUP_NAME_ATTR_KEY, GROUP_NAME_ATTR_DEFAULT);
int dirSearchTimeout = conf.getInt(DIRECTORY_SEARCH_TIMEOUT, DIRECTORY_SEARCH_TIMEOUT_DEFAULT);
SEARCH_CONTROLS.setTimeLimit(dirSearchTimeout);
this.conf = conf;
}
String extractPassword(String pwFile) {
if (pwFile.isEmpty()) {
// If there is no password file defined, we'll assume that we should do
// an anonymous bind
return "";
}
try {
StringBuilder password = new StringBuilder();
Reader reader = new FileReader(pwFile);
int c = reader.read();
while (c > -1) {
password.append((char)c);
c = reader.read();
}
reader.close();
return password.toString();
} catch (IOException ioe) {
throw new RuntimeException("Could not read password file: " + pwFile, ioe);
}
}
}