/**
* 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 static org.apache.hadoop.fs.CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION;
import java.io.IOException;
import java.lang.reflect.UndeclaredThrowableException;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.Principal;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.security.auth.Subject;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.kerberos.KerberosPrincipal;
import javax.security.auth.login.AppConfigurationEntry;
import javax.security.auth.login.LoginContext;
import javax.security.auth.login.LoginException;
import javax.security.auth.login.AppConfigurationEntry.LoginModuleControlFlag;
import javax.security.auth.spi.LoginModule;
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.Configuration;
import org.apache.hadoop.security.SaslRpcServer.AuthMethod;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenIdentifier;
import com.sun.security.auth.NTUserPrincipal;
import com.sun.security.auth.UnixPrincipal;
import com.sun.security.auth.module.Krb5LoginModule;
/**
* User and group information for Hadoop.
* This class wraps around a JAAS Subject and provides methods to determine the
* user's username and groups. It supports both the Windows, Unix and Kerberos
* login modules.
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class UserGroupInformation {
private static final Log LOG = LogFactory.getLog(UserGroupInformation.class);
/**
* A login module that looks at the Kerberos, Unix, or Windows principal and
* adds the corresponding UserName.
*/
@InterfaceAudience.Private
public static class HadoopLoginModule implements LoginModule {
private Subject subject;
@Override
public boolean abort() throws LoginException {
return true;
}
private <T extends Principal> T getCanonicalUser(Class<T> cls) {
for(T user: subject.getPrincipals(cls)) {
return user;
}
return null;
}
@Override
public boolean commit() throws LoginException {
Principal user = null;
// if we are using kerberos, try it out
if (useKerberos) {
user = getCanonicalUser(KerberosPrincipal.class);
}
// if we don't have a kerberos user, use the OS user
if (user == null) {
user = getCanonicalUser(OS_PRINCIPAL_CLASS);
}
// if we found the user, add our principal
if (user != null) {
subject.getPrincipals().add(new User(user.getName()));
return true;
}
LOG.error("Can't find user in " + subject);
throw new LoginException("Can't find user name");
}
@Override
public void initialize(Subject subject, CallbackHandler callbackHandler,
Map<String, ?> sharedState, Map<String, ?> options) {
this.subject = subject;
}
@Override
public boolean login() throws LoginException {
return true;
}
@Override
public boolean logout() throws LoginException {
return true;
}
}
/** Are the static variables that depend on configuration initialized? */
private static boolean isInitialized = false;
/** Should we use Kerberos configuration? */
private static boolean useKerberos;
/** Server-side groups fetching service */
private static Groups groups;
/** The last authentication time */
private static long lastUnsuccessfulAuthenticationAttemptTime;
public static final long MIN_TIME_BEFORE_RELOGIN = 10 * 60 * 1000L;
/**Environment variable pointing to the token cache file*/
public static final String HADOOP_TOKEN_FILE_LOCATION =
"HADOOP_TOKEN_FILE_LOCATION";
/**
* A method to initialize the fields that depend on a configuration.
* Must be called before useKerberos or groups is used.
*/
private static synchronized void ensureInitialized() {
if (!isInitialized) {
initialize(new Configuration());
}
}
/**
* Set the configuration values for UGI.
* @param conf the configuration to use
*/
private static synchronized void initialize(Configuration conf) {
String value = conf.get(HADOOP_SECURITY_AUTHENTICATION);
if (value == null || "simple".equals(value)) {
useKerberos = false;
} else if ("kerberos".equals(value)) {
useKerberos = true;
} else {
throw new IllegalArgumentException("Invalid attribute value for " +
HADOOP_SECURITY_AUTHENTICATION +
" of " + value);
}
// If we haven't set up testing groups, use the configuration to find it
if (!(groups instanceof TestingGroups)) {
groups = Groups.getUserToGroupsMappingService(conf);
}
// Set the configuration for JAAS to be the Hadoop configuration.
// This is done here rather than a static initializer to avoid a
// circular dependence.
javax.security.auth.login.Configuration.setConfiguration
(new HadoopConfiguration());
isInitialized = true;
}
/**
* Set the static configuration for UGI.
* In particular, set the security authentication mechanism and the
* group look up service.
* @param conf the configuration to use
*/
public static void setConfiguration(Configuration conf) {
initialize(conf);
}
/**
* Determine if UserGroupInformation is using Kerberos to determine
* user identities or is relying on simple authentication
*
* @return true if UGI is working in a secure environment
*/
public static boolean isSecurityEnabled() {
ensureInitialized();
return useKerberos;
}
/**
* Information about the logged in user.
*/
private static UserGroupInformation loginUser = null;
private static String keytabPrincipal = null;
private static String keytabFile = null;
private final Subject subject;
private static LoginContext login;
private static final String OS_LOGIN_MODULE_NAME;
private static final Class<? extends Principal> OS_PRINCIPAL_CLASS;
private static final boolean windows =
System.getProperty("os.name").startsWith("Windows");
static {
if (windows) {
OS_LOGIN_MODULE_NAME = "com.sun.security.auth.module.NTLoginModule";
OS_PRINCIPAL_CLASS = NTUserPrincipal.class;
} else {
OS_LOGIN_MODULE_NAME = "com.sun.security.auth.module.UnixLoginModule";
OS_PRINCIPAL_CLASS = UnixPrincipal.class;
}
}
private static class RealUser implements Principal {
private final UserGroupInformation realUser;
RealUser(UserGroupInformation realUser) {
this.realUser = realUser;
}
public String getName() {
return realUser.getUserName();
}
public UserGroupInformation getRealUser() {
return realUser;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
} else if (o == null || getClass() != o.getClass()) {
return false;
} else {
return realUser.equals(((RealUser) o).realUser);
}
}
@Override
public int hashCode() {
return realUser.hashCode();
}
@Override
public String toString() {
return realUser.toString();
}
}
/**
* A JAAS configuration that defines the login modules that we want
* to use for login.
*/
private static class HadoopConfiguration
extends javax.security.auth.login.Configuration {
private static final String SIMPLE_CONFIG_NAME = "hadoop-simple";
private static final String USER_KERBEROS_CONFIG_NAME =
"hadoop-user-kerberos";
private static final String KEYTAB_KERBEROS_CONFIG_NAME =
"hadoop-keytab-kerberos";
private static final AppConfigurationEntry OS_SPECIFIC_LOGIN =
new AppConfigurationEntry(OS_LOGIN_MODULE_NAME,
LoginModuleControlFlag.REQUIRED,
new HashMap<String,String>());
private static final AppConfigurationEntry HADOOP_LOGIN =
new AppConfigurationEntry(HadoopLoginModule.class.getName(),
LoginModuleControlFlag.REQUIRED,
new HashMap<String,String>());
private static final Map<String,String> USER_KERBEROS_OPTIONS =
new HashMap<String,String>();
static {
USER_KERBEROS_OPTIONS.put("doNotPrompt", "true");
USER_KERBEROS_OPTIONS.put("useTicketCache", "true");
USER_KERBEROS_OPTIONS.put("renewTGT", "true");
String ticketCache = System.getenv("KRB5CCNAME");
if (ticketCache != null) {
USER_KERBEROS_OPTIONS.put("ticketCache", ticketCache);
}
}
private static final AppConfigurationEntry USER_KERBEROS_LOGIN =
new AppConfigurationEntry(Krb5LoginModule.class.getName(),
LoginModuleControlFlag.OPTIONAL,
USER_KERBEROS_OPTIONS);
private static final Map<String,String> KEYTAB_KERBEROS_OPTIONS =
new HashMap<String,String>();
static {
KEYTAB_KERBEROS_OPTIONS.put("doNotPrompt", "true");
KEYTAB_KERBEROS_OPTIONS.put("useKeyTab", "true");
KEYTAB_KERBEROS_OPTIONS.put("storeKey", "true");
}
private static final AppConfigurationEntry KEYTAB_KERBEROS_LOGIN =
new AppConfigurationEntry(Krb5LoginModule.class.getName(),
LoginModuleControlFlag.REQUIRED,
KEYTAB_KERBEROS_OPTIONS);
private static final AppConfigurationEntry[] SIMPLE_CONF =
new AppConfigurationEntry[]{OS_SPECIFIC_LOGIN, HADOOP_LOGIN};
private static final AppConfigurationEntry[] USER_KERBEROS_CONF =
new AppConfigurationEntry[]{OS_SPECIFIC_LOGIN, USER_KERBEROS_LOGIN,
HADOOP_LOGIN};
private static final AppConfigurationEntry[] KEYTAB_KERBEROS_CONF =
new AppConfigurationEntry[]{KEYTAB_KERBEROS_LOGIN, HADOOP_LOGIN};
@Override
public AppConfigurationEntry[] getAppConfigurationEntry(String appName) {
if (SIMPLE_CONFIG_NAME.equals(appName)) {
return SIMPLE_CONF;
} else if (USER_KERBEROS_CONFIG_NAME.equals(appName)) {
return USER_KERBEROS_CONF;
} else if (KEYTAB_KERBEROS_CONFIG_NAME.equals(appName)) {
KEYTAB_KERBEROS_OPTIONS.put("keyTab", keytabFile);
KEYTAB_KERBEROS_OPTIONS.put("principal", keytabPrincipal);
return KEYTAB_KERBEROS_CONF;
}
return null;
}
}
/**
* Create a UserGroupInformation for the given subject.
* This does not change the subject or acquire new credentials.
* @param subject the user's subject
*/
UserGroupInformation(Subject subject) {
this.subject = subject;
}
/**
* Return the current user, including any doAs in the current stack.
* @return the current user
* @throws IOException if login fails
*/
public static UserGroupInformation getCurrentUser() throws IOException {
AccessControlContext context = AccessController.getContext();
Subject subject = Subject.getSubject(context);
return subject == null ? getLoginUser() : new UserGroupInformation(subject);
}
/**
* Get the currently logged in user.
* @return the logged in user
* @throws IOException if login fails
*/
public synchronized
static UserGroupInformation getLoginUser() throws IOException {
if (loginUser == null) {
try {
if (isSecurityEnabled()) {
login = new LoginContext(HadoopConfiguration.USER_KERBEROS_CONFIG_NAME);
} else {
login = new LoginContext(HadoopConfiguration.SIMPLE_CONFIG_NAME);
}
login.login();
loginUser = new UserGroupInformation(login.getSubject());
String tokenFile = System.getenv(HADOOP_TOKEN_FILE_LOCATION);
if (tokenFile != null && isSecurityEnabled()) {
TokenStorage.readTokensAndLoadInUGI(tokenFile, new Configuration(), loginUser);
}
} catch (LoginException le) {
throw new IOException("failure to login", le);
}
}
return loginUser;
}
/**
* Log a user in from a keytab file. Loads a user identity from a keytab
* file and login them in. They become the currently logged-in user.
* @param user the principal name to load from the keytab
* @param path the path to the keytab file
* @throws IOException if the keytab file can't be read
*/
public synchronized
static void loginUserFromKeytab(String user,
String path
) throws IOException {
if (!isSecurityEnabled())
return;
keytabFile = path;
keytabPrincipal = user;
try {
login =
new LoginContext(HadoopConfiguration.KEYTAB_KERBEROS_CONFIG_NAME);
login.login();
loginUser = new UserGroupInformation(login.getSubject());
} catch (LoginException le) {
throw new IOException("Login failure for " + user + " from keytab " +
path, le);
}
}
/**
* Re-Login a user in from a keytab file. Loads a user identity from a keytab
* file and login them in. They become the currently logged-in user. This
* method assumes that {@link #loginUserFromKeytab(String, String)} had
* happened already.
* The Subject field of this UserGroupInformation object is updated to have
* the new credentials.
* @throws IOException on a failure
*/
public synchronized void reloginFromKeytab()
throws IOException {
if (!isSecurityEnabled())
return;
if (login == null || keytabFile == null) {
throw new IOException("loginUserFromKeyTab must be done first");
}
if (System.currentTimeMillis() -lastUnsuccessfulAuthenticationAttemptTime <
MIN_TIME_BEFORE_RELOGIN) {
LOG.warn("Not attempting to re-login since the last re-login was " +
"attempted less than " + (MIN_TIME_BEFORE_RELOGIN/1000) + " seconds"+
" before.");
return;
}
try {
LOG.info("Initiating logout for " + getUserName());
//clear up the kerberos state. But the tokens are not cleared! As per
//the Java kerberos login module code, only the kerberos credentials
//are cleared
login.logout();
//login and also update the subject field of this instance to
//have the new credentials (pass it to the LoginContext constructor)
login =
new LoginContext(HadoopConfiguration.KEYTAB_KERBEROS_CONFIG_NAME,
getSubject());
LOG.info("Initiating re-login for " + keytabPrincipal);
login.login();
} catch (LoginException le) {
throw new IOException("Login failure for " + keytabPrincipal +
" from keytab " + keytabFile, le);
}
}
public synchronized static void
setLastUnsuccessfulAuthenticationAttemptTime(long time) {
lastUnsuccessfulAuthenticationAttemptTime = time;
}
public synchronized static boolean isLoginKeytabBased() {
return keytabFile != null;
}
/**
* Create a user from a login name. It is intended to be used for remote
* users in RPC, since it won't have any credentials.
* @param user the full user principal name, must not be empty or null
* @return the UserGroupInformation for the remote user.
*/
public static UserGroupInformation createRemoteUser(String user) {
if (user == null || "".equals(user)) {
throw new IllegalArgumentException("Null user");
}
Subject subject = new Subject();
subject.getPrincipals().add(new User(user));
return new UserGroupInformation(subject);
}
@InterfaceStability.Evolving
public static enum AuthenticationMethod {
SIMPLE,
KERBEROS,
TOKEN,
CERTIFICATE,
KERBEROS_SSL,
PROXY;
}
/* Create a proxy user using username of the effective user and the ugi of the
* real user.
*
* @param effective
* user, UGI for real user.
* @return
*/
public static UserGroupInformation createProxyUser(String user,
UserGroupInformation realUser) {
if (user == null || "".equals(user)) {
throw new IllegalArgumentException("Null user");
}
if (realUser == null) {
throw new IllegalArgumentException("Null real user");
}
Subject subject = new Subject();
subject.getPrincipals().add(new User(user));
subject.getPrincipals().add(new RealUser(realUser));
return new UserGroupInformation(subject);
}
public UserGroupInformation getRealUser() {
for (RealUser p: subject.getPrincipals(RealUser.class)) {
return p.getRealUser();
}
return null;
}
/**
* This class is used for storing the groups for testing. It stores a local
* map that has the translation of usernames to groups.
*/
private static class TestingGroups extends Groups {
private final Map<String, List<String>> userToGroupsMapping =
new HashMap<String,List<String>>();
private TestingGroups() {
super(new org.apache.hadoop.conf.Configuration());
}
@Override
public List<String> getGroups(String user) {
List<String> result = userToGroupsMapping.get(user);
if (result == null) {
result = new ArrayList<String>();
}
return result;
}
private void setUserGroups(String user, String[] groups) {
userToGroupsMapping.put(user, Arrays.asList(groups));
}
}
/**
* Create a UGI for testing HDFS and MapReduce
* @param user the full user principal name
* @param userGroups the names of the groups that the user belongs to
* @return a fake user for running unit tests
*/
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
public static UserGroupInformation createUserForTesting(String user,
String[] userGroups) {
ensureInitialized();
UserGroupInformation ugi = createRemoteUser(user);
// make sure that the testing object is setup
if (!(groups instanceof TestingGroups)) {
groups = new TestingGroups();
}
// add the user groups
((TestingGroups) groups).setUserGroups(ugi.getShortUserName(), userGroups);
return ugi;
}
/**
* Create a proxy user UGI for testing HDFS and MapReduce
*
* @param user
* the full user principal name for effective user
* @param realUser
* UGI of the real user
* @param userGroups
* the names of the groups that the user belongs to
* @return a fake user for running unit tests
*/
@InterfaceAudience.LimitedPrivate( { "HDFS", "MapReduce" })
public static UserGroupInformation createProxyUserForTesting(String user,
UserGroupInformation realUser, String[] userGroups) {
ensureInitialized();
UserGroupInformation ugi = createProxyUser(user, realUser);
// make sure that the testing object is setup
if (!(groups instanceof TestingGroups)) {
groups = new TestingGroups();
}
// add the user groups
((TestingGroups) groups).setUserGroups(ugi.getShortUserName(), userGroups);
return ugi;
}
/**
* Get the user's login name.
* @return the user's name up to the first '/' or '@'.
*/
public String getShortUserName() {
for (User p: subject.getPrincipals(User.class)) {
return p.getShortName();
}
return null;
}
/**
* Get the user's full principal name.
* @return the user's full principal name.
*/
public String getUserName() {
for (User p: subject.getPrincipals(User.class)) {
return p.getName();
}
return null;
}
/**
* Add a token to this UGI
*
* @param token Token to be added
* @return true on successful add of new token
*/
public synchronized boolean addToken(Token<? extends TokenIdentifier> token) {
return subject.getPrivateCredentials().add(token);
}
/**
* Obtain the collection of tokens associated with this user.
*
* @return an unmodifiable collection of tokens associated with user
*/
public synchronized
Collection<Token<? extends TokenIdentifier>> getTokens() {
Set<Object> creds = subject.getPrivateCredentials();
List<Token<?>> result = new ArrayList<Token<?>>(creds.size());
for(Object o: creds) {
if (o instanceof Token<?>) {
result.add((Token<?>) o);
}
}
return Collections.unmodifiableList(result);
}
/**
* Get the group names for this user.
* @return the list of users with the primary group first. If the command
* fails, it returns an empty list.
*/
public synchronized String[] getGroupNames() {
ensureInitialized();
try {
List<String> result = groups.getGroups(getShortUserName());
return result.toArray(new String[result.size()]);
} catch (IOException ie) {
LOG.warn("No groups available for user " + getShortUserName());
return new String[0];
}
}
/**
* Return the username.
*/
@Override
public String toString() {
if (getRealUser() != null) {
return getUserName() + " via " + getRealUser().toString();
} else {
return getUserName();
}
}
/**
* Sets the authentication method in the subject
*
* @param authMethod
*/
public synchronized
void setAuthenticationMethod(AuthenticationMethod authMethod) {
for (User p : subject.getPrincipals(User.class)) {
p.setAuthenticationMethod(authMethod);
}
}
/**
* Get the authentication method from the subject
*
* @return AuthenticationMethod in the subject, null if not present.
*/
public synchronized AuthenticationMethod getAuthenticationMethod() {
for (User p: subject.getPrincipals(User.class)) {
return p.getAuthenticationMethod();
}
return null;
}
/**
* Compare the subjects to see if they are equal to each other.
*/
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
} else if (o == null || getClass() != o.getClass()) {
return false;
} else {
return subject.equals(((UserGroupInformation) o).subject);
}
}
/**
* Return the hash of the subject.
*/
@Override
public int hashCode() {
return subject.hashCode();
}
/**
* Get the underlying subject from this ugi.
* @return the subject that represents this user.
*/
protected Subject getSubject() {
return subject;
}
/**
* Run the given action as the user.
* @param <T> the return type of the run method
* @param action the method to execute
* @return the value from the run method
*/
public <T> T doAs(PrivilegedAction<T> action) {
return Subject.doAs(subject, action);
}
/**
* Run the given action as the user, potentially throwing an exception.
* @param <T> the return type of the run method
* @param action the method to execute
* @return the value from the run method
* @throws IOException if the action throws an IOException
* @throws Error if the action throws an Error
* @throws RuntimeException if the action throws a RuntimeException
* @throws InterruptedException if the action throws an InterruptedException
* @throws UndeclaredThrowableException if the action throws something else
*/
public <T> T doAs(PrivilegedExceptionAction<T> action
) throws IOException, InterruptedException {
try {
return Subject.doAs(subject, action);
} catch (PrivilegedActionException pae) {
Throwable cause = pae.getCause();
if (cause instanceof IOException) {
throw (IOException) cause;
} else if (cause instanceof Error) {
throw (Error) cause;
} else if (cause instanceof RuntimeException) {
throw (RuntimeException) cause;
} else if (cause instanceof InterruptedException) {
throw (InterruptedException) cause;
} else {
throw new UndeclaredThrowableException(pae,"Unknown exception in doAs");
}
}
}
private void print() throws IOException {
System.out.println("User: " + getUserName());
System.out.print("Group Ids: ");
System.out.println();
String[] groups = getGroupNames();
System.out.print("Groups: ");
for(int i=0; i < groups.length; i++) {
System.out.print(groups[i] + " ");
}
System.out.println();
}
/**
* A test method to print out the current user's UGI.
* @param args if there are two arguments, read the user from the keytab
* and print it out.
* @throws Exception
*/
public static void main(String [] args) throws Exception {
System.out.println("Getting UGI for current user");
UserGroupInformation ugi = getCurrentUser();
ugi.print();
System.out.println("UGI: " + ugi);
System.out.println("============================================================");
if (args.length == 2) {
System.out.println("Getting UGI from keytab....");
loginUserFromKeytab(args[0], args[1]);
getCurrentUser().print();
System.out.println("Keytab: " + ugi);
}
}
}