/**
* 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.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Hashtable;
import java.util.List;
import java.util.HashSet;
import java.util.Collection;
import java.util.Set;
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 javax.naming.ldap.LdapName;
import javax.naming.ldap.Rdn;
import org.apache.commons.io.Charsets;
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 attempts to resolve group hierarchies,
* to a configurable limit.
* If the limit is 0, in order to be considered a member of a group,
* the user must be an explicit member in LDAP. Otherwise, it will traverse the
* group hierarchy n levels up.
*/
@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 MEMBEROF_ATTR_KEY =
LDAP_CONFIG_PREFIX + ".search.attr.memberof";
public static final String MEMBEROF_ATTR_DEFAULT = "";
/*
* 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";
/*
* How many levels to traverse when checking for groups in the org hierarchy
*/
public static final String GROUP_HIERARCHY_LEVELS_KEY =
LDAP_CONFIG_PREFIX + ".search.group.hierarchy.levels";
public static final int GROUP_HIERARCHY_LEVELS_DEFAULT = 0;
/*
* LDAP attribute names to use when doing posix-like lookups
*/
public static final String POSIX_UID_ATTR_KEY = LDAP_CONFIG_PREFIX + ".posix.attr.uid.name";
public static final String POSIX_UID_ATTR_DEFAULT = "uidNumber";
public static final String POSIX_GID_ATTR_KEY = LDAP_CONFIG_PREFIX + ".posix.attr.gid.name";
public static final String POSIX_GID_ATTR_DEFAULT = "gidNumber";
/*
* Posix attributes
*/
public static final String POSIX_GROUP = "posixGroup";
public static final String POSIX_ACCOUNT = "posixAccount";
/*
* 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
public static final String CONNECTION_TIMEOUT =
LDAP_CONFIG_PREFIX + ".connection.timeout.ms";
public static final int CONNECTION_TIMEOUT_DEFAULT = 60 * 1000; // 60 seconds
public static final String READ_TIMEOUT =
LDAP_CONFIG_PREFIX + ".read.timeout.ms";
public static final int READ_TIMEOUT_DEFAULT = 60 * 1000; // 60 seconds
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 memberOfAttr;
private String groupMemberAttr;
private String groupNameAttr;
private int groupHierarchyLevels;
private String posixUidAttr;
private String posixGidAttr;
private boolean isPosix;
private boolean useOneQuery;
public static final 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) {
/*
* 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.
*/
for(int retry = 0; retry < RECONNECT_RETRY_COUNT; retry++) {
try {
return doGetGroups(user, groupHierarchyLevels);
} catch (NamingException e) {
LOG.warn("Failed to get groups for user " + user + " (retry=" + retry
+ ") by " + e);
LOG.trace("TRACE", e);
}
//reset ctx so that new DirContext can be created with new connection
this.ctx = null;
}
return Collections.emptyList();
}
/**
* A helper method to get the Relative Distinguished Name (RDN) from
* Distinguished name (DN). According to Active Directory documentation,
* a group object's RDN is a CN.
*
* @param distinguishedName A string representing a distinguished name.
* @throws NamingException if the DN is malformed.
* @return a string which represents the RDN
*/
private String getRelativeDistinguishedName(String distinguishedName)
throws NamingException {
LdapName ldn = new LdapName(distinguishedName);
List<Rdn> rdns = ldn.getRdns();
if (rdns.isEmpty()) {
throw new NamingException("DN is empty");
}
Rdn rdn = rdns.get(rdns.size()-1);
if (rdn.getType().equalsIgnoreCase(groupNameAttr)) {
String groupName = (String)rdn.getValue();
return groupName;
}
throw new NamingException("Unable to find RDN: The DN " +
distinguishedName + " is malformed.");
}
/**
* Look up groups using posixGroups semantics. Use posix gid/uid to find
* groups of the user.
*
* @param result the result object returned from the prior user lookup.
* @param c the context object of the LDAP connection.
* @return an object representing the search result.
*
* @throws NamingException if the server does not support posixGroups
* semantics.
*/
private NamingEnumeration<SearchResult> lookupPosixGroup(SearchResult result,
DirContext c) throws NamingException {
String gidNumber = null;
String uidNumber = null;
Attribute gidAttribute = result.getAttributes().get(posixGidAttr);
Attribute uidAttribute = result.getAttributes().get(posixUidAttr);
String reason = "";
if (gidAttribute == null) {
reason = "Can't find attribute '" + posixGidAttr + "'.";
} else {
gidNumber = gidAttribute.get().toString();
}
if (uidAttribute == null) {
reason = "Can't find attribute '" + posixUidAttr + "'.";
} else {
uidNumber = uidAttribute.get().toString();
}
if (uidNumber != null && gidNumber != null) {
return c.search(baseDN,
"(&"+ groupSearchFilter + "(|(" + posixGidAttr + "={0})" +
"(" + groupMemberAttr + "={1})))",
new Object[] {gidNumber, uidNumber},
SEARCH_CONTROLS);
}
throw new NamingException("The server does not support posixGroups " +
"semantics. Reason: " + reason +
" Returned user object: " + result.toString());
}
/**
* Perform the second query to get the groups of the user.
*
* If posixGroups is enabled, use use posix gid/uid to find.
* Otherwise, use the general group member attribute to find it.
*
* @param result the result object returned from the prior user lookup.
* @param c the context object of the LDAP connection.
* @return a list of strings representing group names of the user.
* @throws NamingException if unable to find group names
*/
private List<String> lookupGroup(SearchResult result, DirContext c,
int goUpHierarchy)
throws NamingException {
List<String> groups = new ArrayList<String>();
Set<String> groupDNs = new HashSet<String>();
NamingEnumeration<SearchResult> groupResults = null;
// perform the second LDAP query
if (isPosix) {
groupResults = lookupPosixGroup(result, c);
} else {
String userDn = result.getNameInNamespace();
groupResults =
c.search(baseDN,
"(&" + groupSearchFilter + "(" + groupMemberAttr + "={0}))",
new Object[]{userDn},
SEARCH_CONTROLS);
}
// if the second query is successful, group objects of the user will be
// returned. Get group names from the returned objects.
if (groupResults != null) {
while (groupResults.hasMoreElements()) {
SearchResult groupResult = groupResults.nextElement();
getGroupNames(groupResult, groups, groupDNs, goUpHierarchy > 0);
}
if (goUpHierarchy > 0 && !isPosix) {
// convert groups to a set to ensure uniqueness
Set<String> groupset = new HashSet<String>(groups);
goUpGroupHierarchy(groupDNs, goUpHierarchy, groupset);
// convert set back to list for compatibility
groups = new ArrayList<String>(groupset);
}
}
return groups;
}
/**
* Perform LDAP queries to get group names of a user.
*
* Perform the first LDAP query to get the user object using the user's name.
* If one-query is enabled, retrieve the group names from the user object.
* If one-query is disabled, or if it failed, perform the second query to
* get the groups.
*
* @param user user name
* @return a list of group names for the user. If the user can not be found,
* return an empty string array.
* @throws NamingException if unable to get group names
*/
List<String> doGetGroups(String user, int goUpHierarchy)
throws NamingException {
DirContext c = getDirContext();
// Search for the user. We'll only ever need to look at the first result
NamingEnumeration<SearchResult> results = c.search(baseDN,
userSearchFilter, new Object[]{user}, SEARCH_CONTROLS);
// return empty list if the user can not be found.
if (!results.hasMoreElements()) {
if (LOG.isDebugEnabled()) {
LOG.debug("doGetGroups(" + user + ") returned no groups because the " +
"user is not found.");
}
return new ArrayList<String>();
}
SearchResult result = results.nextElement();
List<String> groups = null;
if (useOneQuery) {
try {
/**
* For Active Directory servers, the user object has an attribute
* 'memberOf' that represents the DNs of group objects to which the
* user belongs. So the second query may be skipped.
*/
Attribute groupDNAttr = result.getAttributes().get(memberOfAttr);
if (groupDNAttr == null) {
throw new NamingException("The user object does not have '" +
memberOfAttr + "' attribute." +
"Returned user object: " + result.toString());
}
groups = new ArrayList<String>();
NamingEnumeration groupEnumeration = groupDNAttr.getAll();
while (groupEnumeration.hasMore()) {
String groupDN = groupEnumeration.next().toString();
groups.add(getRelativeDistinguishedName(groupDN));
}
} catch (NamingException e) {
// If the first lookup failed, fall back to the typical scenario.
LOG.info("Failed to get groups from the first lookup. Initiating " +
"the second LDAP query using the user's DN.", e);
}
}
if (groups == null || groups.isEmpty() || goUpHierarchy > 0) {
groups = lookupGroup(result, c, goUpHierarchy);
}
if (LOG.isDebugEnabled()) {
LOG.debug("doGetGroups(" + user + ") returned " + groups);
}
return groups;
}
/* Helper function to get group name from search results.
*/
void getGroupNames(SearchResult groupResult, Collection<String> groups,
Collection<String> groupDNs, boolean doGetDNs)
throws NamingException {
Attribute groupName = groupResult.getAttributes().get(groupNameAttr);
if (groupName == null) {
throw new NamingException("The group object does not have " +
"attribute '" + groupNameAttr + "'.");
}
groups.add(groupName.get().toString());
if (doGetDNs) {
groupDNs.add(groupResult.getNameInNamespace());
}
}
/* Implementation for walking up the ldap hierarchy
* This function will iteratively find the super-group memebership of
* groups listed in groupDNs and add them to
* the groups set. It will walk up the hierarchy goUpHierarchy levels.
* Note: This is an expensive operation and settings higher than 1
* are NOT recommended as they will impact both the speed and
* memory usage of all operations.
* The maximum time for this function will be bounded by the ldap query
* timeout and the number of ldap queries that it will make, which is
* max(Recur Depth in LDAP, goUpHierarcy) * DIRECTORY_SEARCH_TIMEOUT
*
* @param ctx - The context for contacting the ldap server
* @param groupDNs - the distinguished name of the groups whose parents we
* want to look up
* @param goUpHierarchy - the number of levels to go up,
* @param groups - Output variable to store all groups that will be added
*/
void goUpGroupHierarchy(Set<String> groupDNs,
int goUpHierarchy,
Set<String> groups)
throws NamingException {
if (goUpHierarchy <= 0 || groups.isEmpty()) {
return;
}
DirContext context = getDirContext();
Set<String> nextLevelGroups = new HashSet<String>();
StringBuilder filter = new StringBuilder();
filter.append("(&").append(groupSearchFilter).append("(|");
for (String dn : groupDNs) {
filter.append("(").append(groupMemberAttr).append("=")
.append(dn).append(")");
}
filter.append("))");
LOG.debug("Ldap group query string: " + filter.toString());
NamingEnumeration<SearchResult> groupResults =
context.search(baseDN,
filter.toString(),
SEARCH_CONTROLS);
while (groupResults.hasMoreElements()) {
SearchResult groupResult = groupResults.nextElement();
getGroupNames(groupResult, groups, nextLevelGroups, true);
}
goUpGroupHierarchy(nextLevelGroups, goUpHierarchy - 1, groups);
}
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);
env.put("com.sun.jndi.ldap.connect.timeout", conf.get(CONNECTION_TIMEOUT,
String.valueOf(CONNECTION_TIMEOUT_DEFAULT)));
env.put("com.sun.jndi.ldap.read.timeout", conf.get(READ_TIMEOUT,
String.valueOf(READ_TIMEOUT_DEFAULT)));
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 = getPassword(conf, LDAP_KEYSTORE_PASSWORD_KEY,
LDAP_KEYSTORE_PASSWORD_DEFAULT);
if (keystorePass.isEmpty()) {
keystorePass = extractPassword(conf.get(LDAP_KEYSTORE_PASSWORD_FILE_KEY,
LDAP_KEYSTORE_PASSWORD_FILE_DEFAULT));
}
bindUser = conf.get(BIND_USER_KEY, BIND_USER_DEFAULT);
bindPassword = getPassword(conf, 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);
isPosix = groupSearchFilter.contains(POSIX_GROUP) && userSearchFilter
.contains(POSIX_ACCOUNT);
memberOfAttr =
conf.get(MEMBEROF_ATTR_KEY, MEMBEROF_ATTR_DEFAULT);
// if memberOf attribute is set, resolve group names from the attribute
// of user objects.
useOneQuery = !memberOfAttr.isEmpty();
groupMemberAttr =
conf.get(GROUP_MEMBERSHIP_ATTR_KEY, GROUP_MEMBERSHIP_ATTR_DEFAULT);
groupNameAttr =
conf.get(GROUP_NAME_ATTR_KEY, GROUP_NAME_ATTR_DEFAULT);
groupHierarchyLevels =
conf.getInt(GROUP_HIERARCHY_LEVELS_KEY, GROUP_HIERARCHY_LEVELS_DEFAULT);
posixUidAttr =
conf.get(POSIX_UID_ATTR_KEY, POSIX_UID_ATTR_DEFAULT);
posixGidAttr =
conf.get(POSIX_GID_ATTR_KEY, POSIX_GID_ATTR_DEFAULT);
int dirSearchTimeout = conf.getInt(DIRECTORY_SEARCH_TIMEOUT, DIRECTORY_SEARCH_TIMEOUT_DEFAULT);
SEARCH_CONTROLS.setTimeLimit(dirSearchTimeout);
// Limit the attributes returned to only those required to speed up the search.
// See HADOOP-10626 and HADOOP-12001 for more details.
String[] returningAttributes;
if (useOneQuery) {
returningAttributes = new String[] {
groupNameAttr, posixUidAttr, posixGidAttr, memberOfAttr};
} else {
returningAttributes = new String[] {
groupNameAttr, posixUidAttr, posixGidAttr};
}
SEARCH_CONTROLS.setReturningAttributes(returningAttributes);
this.conf = conf;
}
String getPassword(Configuration conf, String alias, String defaultPass) {
String password = defaultPass;
try {
char[] passchars = conf.getPassword(alias);
if (passchars != null) {
password = new String(passchars);
}
} catch (IOException ioe) {
LOG.warn("Exception while trying to get password for alias " + alias
+ ": ", ioe);
}
return password;
}
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 "";
}
StringBuilder password = new StringBuilder();
try (Reader reader = new InputStreamReader(
new FileInputStream(pwFile), Charsets.UTF_8)) {
int c = reader.read();
while (c > -1) {
password.append((char)c);
c = reader.read();
}
return password.toString().trim();
} catch (IOException ioe) {
throw new RuntimeException("Could not read password file: " + pwFile, ioe);
}
}
}