001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 package org.apache.hadoop.security;
019
020 import static org.apache.hadoop.fs.CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION;
021
022 import java.io.IOException;
023 import java.lang.reflect.UndeclaredThrowableException;
024 import java.security.AccessControlContext;
025 import java.security.AccessController;
026 import java.security.Principal;
027 import java.security.PrivilegedAction;
028 import java.security.PrivilegedActionException;
029 import java.security.PrivilegedExceptionAction;
030 import java.util.ArrayList;
031 import java.util.Arrays;
032 import java.util.Collection;
033 import java.util.Collections;
034 import java.util.HashMap;
035 import java.util.List;
036 import java.util.Map;
037 import java.util.Set;
038
039 import javax.security.auth.Subject;
040 import javax.security.auth.callback.CallbackHandler;
041 import javax.security.auth.kerberos.KerberosKey;
042 import javax.security.auth.kerberos.KerberosPrincipal;
043 import javax.security.auth.kerberos.KerberosTicket;
044 import javax.security.auth.login.AppConfigurationEntry;
045 import javax.security.auth.login.LoginContext;
046 import javax.security.auth.login.LoginException;
047 import javax.security.auth.login.AppConfigurationEntry.LoginModuleControlFlag;
048 import javax.security.auth.spi.LoginModule;
049
050 import org.apache.commons.logging.Log;
051 import org.apache.commons.logging.LogFactory;
052 import org.apache.hadoop.classification.InterfaceAudience;
053 import org.apache.hadoop.classification.InterfaceStability;
054 import org.apache.hadoop.conf.Configuration;
055 import org.apache.hadoop.fs.Path;
056 import org.apache.hadoop.metrics2.annotation.Metric;
057 import org.apache.hadoop.metrics2.annotation.Metrics;
058 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
059 import org.apache.hadoop.metrics2.lib.MutableRate;
060 import org.apache.hadoop.security.authentication.util.KerberosName;
061 import org.apache.hadoop.security.token.Token;
062 import org.apache.hadoop.security.token.TokenIdentifier;
063 import org.apache.hadoop.util.Shell;
064
065 import com.sun.security.auth.NTUserPrincipal;
066 import com.sun.security.auth.UnixPrincipal;
067 import com.sun.security.auth.module.Krb5LoginModule;
068
069 /**
070 * User and group information for Hadoop.
071 * This class wraps around a JAAS Subject and provides methods to determine the
072 * user's username and groups. It supports both the Windows, Unix and Kerberos
073 * login modules.
074 */
075 @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
076 @InterfaceStability.Evolving
077 public class UserGroupInformation {
078 private static final Log LOG = LogFactory.getLog(UserGroupInformation.class);
079 /**
080 * Percentage of the ticket window to use before we renew ticket.
081 */
082 private static final float TICKET_RENEW_WINDOW = 0.80f;
083 static final String HADOOP_USER_NAME = "HADOOP_USER_NAME";
084
085 /**
086 * UgiMetrics maintains UGI activity statistics
087 * and publishes them through the metrics interfaces.
088 */
089 @Metrics(about="User and group related metrics", context="ugi")
090 static class UgiMetrics {
091 @Metric("Rate of successful kerberos logins and latency (milliseconds)")
092 MutableRate loginSuccess;
093 @Metric("Rate of failed kerberos logins and latency (milliseconds)")
094 MutableRate loginFailure;
095
096 static UgiMetrics create() {
097 return DefaultMetricsSystem.instance().register(new UgiMetrics());
098 }
099 }
100
101 /**
102 * A login module that looks at the Kerberos, Unix, or Windows principal and
103 * adds the corresponding UserName.
104 */
105 @InterfaceAudience.Private
106 public static class HadoopLoginModule implements LoginModule {
107 private Subject subject;
108
109 @Override
110 public boolean abort() throws LoginException {
111 return true;
112 }
113
114 private <T extends Principal> T getCanonicalUser(Class<T> cls) {
115 for(T user: subject.getPrincipals(cls)) {
116 return user;
117 }
118 return null;
119 }
120
121 @Override
122 public boolean commit() throws LoginException {
123 if (LOG.isDebugEnabled()) {
124 LOG.debug("hadoop login commit");
125 }
126 // if we already have a user, we are done.
127 if (!subject.getPrincipals(User.class).isEmpty()) {
128 if (LOG.isDebugEnabled()) {
129 LOG.debug("using existing subject:"+subject.getPrincipals());
130 }
131 return true;
132 }
133 Principal user = null;
134 // if we are using kerberos, try it out
135 if (useKerberos) {
136 user = getCanonicalUser(KerberosPrincipal.class);
137 if (LOG.isDebugEnabled()) {
138 LOG.debug("using kerberos user:"+user);
139 }
140 }
141 //If we don't have a kerberos user and security is disabled, check
142 //if user is specified in the environment or properties
143 if (!isSecurityEnabled() && (user == null)) {
144 String envUser = System.getenv(HADOOP_USER_NAME);
145 if (envUser == null) {
146 envUser = System.getProperty(HADOOP_USER_NAME);
147 }
148 user = envUser == null ? null : new User(envUser);
149 }
150 // use the OS user
151 if (user == null) {
152 user = getCanonicalUser(OS_PRINCIPAL_CLASS);
153 if (LOG.isDebugEnabled()) {
154 LOG.debug("using local user:"+user);
155 }
156 }
157 // if we found the user, add our principal
158 if (user != null) {
159 subject.getPrincipals().add(new User(user.getName()));
160 return true;
161 }
162 LOG.error("Can't find user in " + subject);
163 throw new LoginException("Can't find user name");
164 }
165
166 @Override
167 public void initialize(Subject subject, CallbackHandler callbackHandler,
168 Map<String, ?> sharedState, Map<String, ?> options) {
169 this.subject = subject;
170 }
171
172 @Override
173 public boolean login() throws LoginException {
174 if (LOG.isDebugEnabled()) {
175 LOG.debug("hadoop login");
176 }
177 return true;
178 }
179
180 @Override
181 public boolean logout() throws LoginException {
182 if (LOG.isDebugEnabled()) {
183 LOG.debug("hadoop logout");
184 }
185 return true;
186 }
187 }
188
189 /** Metrics to track UGI activity */
190 static UgiMetrics metrics = UgiMetrics.create();
191 /** Are the static variables that depend on configuration initialized? */
192 private static boolean isInitialized = false;
193 /** Should we use Kerberos configuration? */
194 private static boolean useKerberos;
195 /** Server-side groups fetching service */
196 private static Groups groups;
197 /** The configuration to use */
198 private static Configuration conf;
199
200
201 /** Leave 10 minutes between relogin attempts. */
202 private static final long MIN_TIME_BEFORE_RELOGIN = 10 * 60 * 1000L;
203
204 /**Environment variable pointing to the token cache file*/
205 public static final String HADOOP_TOKEN_FILE_LOCATION =
206 "HADOOP_TOKEN_FILE_LOCATION";
207
208 /**
209 * A method to initialize the fields that depend on a configuration.
210 * Must be called before useKerberos or groups is used.
211 */
212 private static synchronized void ensureInitialized() {
213 if (!isInitialized) {
214 initialize(new Configuration(), KerberosName.hasRulesBeenSet());
215 }
216 }
217
218 /**
219 * Initialize UGI and related classes.
220 * @param conf the configuration to use
221 */
222 private static synchronized void initialize(Configuration conf, boolean skipRulesSetting) {
223 initUGI(conf);
224 // give the configuration on how to translate Kerberos names
225 try {
226 if (!skipRulesSetting) {
227 HadoopKerberosName.setConfiguration(conf);
228 }
229 } catch (IOException ioe) {
230 throw new RuntimeException("Problem with Kerberos auth_to_local name " +
231 "configuration", ioe);
232 }
233 }
234
235 /**
236 * Set the configuration values for UGI.
237 * @param conf the configuration to use
238 */
239 private static synchronized void initUGI(Configuration conf) {
240 String value = conf.get(HADOOP_SECURITY_AUTHENTICATION);
241 if (value == null || "simple".equals(value)) {
242 useKerberos = false;
243 } else if ("kerberos".equals(value)) {
244 useKerberos = true;
245 } else {
246 throw new IllegalArgumentException("Invalid attribute value for " +
247 HADOOP_SECURITY_AUTHENTICATION +
248 " of " + value);
249 }
250 // If we haven't set up testing groups, use the configuration to find it
251 if (!(groups instanceof TestingGroups)) {
252 groups = Groups.getUserToGroupsMappingService(conf);
253 }
254 isInitialized = true;
255 UserGroupInformation.conf = conf;
256 }
257
258 /**
259 * Set the static configuration for UGI.
260 * In particular, set the security authentication mechanism and the
261 * group look up service.
262 * @param conf the configuration to use
263 */
264 public static void setConfiguration(Configuration conf) {
265 initialize(conf, false);
266 }
267
268 /**
269 * Determine if UserGroupInformation is using Kerberos to determine
270 * user identities or is relying on simple authentication
271 *
272 * @return true if UGI is working in a secure environment
273 */
274 public static boolean isSecurityEnabled() {
275 ensureInitialized();
276 return useKerberos;
277 }
278
279 /**
280 * Information about the logged in user.
281 */
282 private static UserGroupInformation loginUser = null;
283 private static String keytabPrincipal = null;
284 private static String keytabFile = null;
285
286 private final Subject subject;
287 // All non-static fields must be read-only caches that come from the subject.
288 private final User user;
289 private final boolean isKeytab;
290 private final boolean isKrbTkt;
291
292 private static final String OS_LOGIN_MODULE_NAME;
293 private static final Class<? extends Principal> OS_PRINCIPAL_CLASS;
294 private static final boolean windows =
295 System.getProperty("os.name").startsWith("Windows");
296 static {
297 if (windows) {
298 OS_LOGIN_MODULE_NAME = "com.sun.security.auth.module.NTLoginModule";
299 OS_PRINCIPAL_CLASS = NTUserPrincipal.class;
300 } else {
301 OS_LOGIN_MODULE_NAME = "com.sun.security.auth.module.UnixLoginModule";
302 OS_PRINCIPAL_CLASS = UnixPrincipal.class;
303 }
304 }
305
306 private static class RealUser implements Principal {
307 private final UserGroupInformation realUser;
308
309 RealUser(UserGroupInformation realUser) {
310 this.realUser = realUser;
311 }
312
313 public String getName() {
314 return realUser.getUserName();
315 }
316
317 public UserGroupInformation getRealUser() {
318 return realUser;
319 }
320
321 @Override
322 public boolean equals(Object o) {
323 if (this == o) {
324 return true;
325 } else if (o == null || getClass() != o.getClass()) {
326 return false;
327 } else {
328 return realUser.equals(((RealUser) o).realUser);
329 }
330 }
331
332 @Override
333 public int hashCode() {
334 return realUser.hashCode();
335 }
336
337 @Override
338 public String toString() {
339 return realUser.toString();
340 }
341 }
342
343 /**
344 * A JAAS configuration that defines the login modules that we want
345 * to use for login.
346 */
347 private static class HadoopConfiguration
348 extends javax.security.auth.login.Configuration {
349 private static final String SIMPLE_CONFIG_NAME = "hadoop-simple";
350 private static final String USER_KERBEROS_CONFIG_NAME =
351 "hadoop-user-kerberos";
352 private static final String KEYTAB_KERBEROS_CONFIG_NAME =
353 "hadoop-keytab-kerberos";
354
355 private static final Map<String, String> BASIC_JAAS_OPTIONS =
356 new HashMap<String,String>();
357 static {
358 String jaasEnvVar = System.getenv("HADOOP_JAAS_DEBUG");
359 if (jaasEnvVar != null && "true".equalsIgnoreCase(jaasEnvVar)) {
360 BASIC_JAAS_OPTIONS.put("debug", "true");
361 }
362 }
363
364 private static final AppConfigurationEntry OS_SPECIFIC_LOGIN =
365 new AppConfigurationEntry(OS_LOGIN_MODULE_NAME,
366 LoginModuleControlFlag.REQUIRED,
367 BASIC_JAAS_OPTIONS);
368 private static final AppConfigurationEntry HADOOP_LOGIN =
369 new AppConfigurationEntry(HadoopLoginModule.class.getName(),
370 LoginModuleControlFlag.REQUIRED,
371 BASIC_JAAS_OPTIONS);
372 private static final Map<String,String> USER_KERBEROS_OPTIONS =
373 new HashMap<String,String>();
374 static {
375 USER_KERBEROS_OPTIONS.put("doNotPrompt", "true");
376 USER_KERBEROS_OPTIONS.put("useTicketCache", "true");
377 USER_KERBEROS_OPTIONS.put("renewTGT", "true");
378 String ticketCache = System.getenv("KRB5CCNAME");
379 if (ticketCache != null) {
380 USER_KERBEROS_OPTIONS.put("ticketCache", ticketCache);
381 }
382 USER_KERBEROS_OPTIONS.putAll(BASIC_JAAS_OPTIONS);
383 }
384 private static final AppConfigurationEntry USER_KERBEROS_LOGIN =
385 new AppConfigurationEntry(Krb5LoginModule.class.getName(),
386 LoginModuleControlFlag.OPTIONAL,
387 USER_KERBEROS_OPTIONS);
388 private static final Map<String,String> KEYTAB_KERBEROS_OPTIONS =
389 new HashMap<String,String>();
390 static {
391 KEYTAB_KERBEROS_OPTIONS.put("doNotPrompt", "true");
392 KEYTAB_KERBEROS_OPTIONS.put("useKeyTab", "true");
393 KEYTAB_KERBEROS_OPTIONS.put("storeKey", "true");
394 KEYTAB_KERBEROS_OPTIONS.put("refreshKrb5Config", "true");
395 KEYTAB_KERBEROS_OPTIONS.putAll(BASIC_JAAS_OPTIONS);
396 }
397 private static final AppConfigurationEntry KEYTAB_KERBEROS_LOGIN =
398 new AppConfigurationEntry(Krb5LoginModule.class.getName(),
399 LoginModuleControlFlag.REQUIRED,
400 KEYTAB_KERBEROS_OPTIONS);
401
402 private static final AppConfigurationEntry[] SIMPLE_CONF =
403 new AppConfigurationEntry[]{OS_SPECIFIC_LOGIN, HADOOP_LOGIN};
404
405 private static final AppConfigurationEntry[] USER_KERBEROS_CONF =
406 new AppConfigurationEntry[]{OS_SPECIFIC_LOGIN, USER_KERBEROS_LOGIN,
407 HADOOP_LOGIN};
408
409 private static final AppConfigurationEntry[] KEYTAB_KERBEROS_CONF =
410 new AppConfigurationEntry[]{KEYTAB_KERBEROS_LOGIN, HADOOP_LOGIN};
411
412 @Override
413 public AppConfigurationEntry[] getAppConfigurationEntry(String appName) {
414 if (SIMPLE_CONFIG_NAME.equals(appName)) {
415 return SIMPLE_CONF;
416 } else if (USER_KERBEROS_CONFIG_NAME.equals(appName)) {
417 return USER_KERBEROS_CONF;
418 } else if (KEYTAB_KERBEROS_CONFIG_NAME.equals(appName)) {
419 KEYTAB_KERBEROS_OPTIONS.put("keyTab", keytabFile);
420 KEYTAB_KERBEROS_OPTIONS.put("principal", keytabPrincipal);
421 return KEYTAB_KERBEROS_CONF;
422 }
423 return null;
424 }
425 }
426
427 private static LoginContext
428 newLoginContext(String appName, Subject subject) throws LoginException {
429 // Temporarily switch the thread's ContextClassLoader to match this
430 // class's classloader, so that we can properly load HadoopLoginModule
431 // from the JAAS libraries.
432 Thread t = Thread.currentThread();
433 ClassLoader oldCCL = t.getContextClassLoader();
434 t.setContextClassLoader(HadoopLoginModule.class.getClassLoader());
435 try {
436 return new LoginContext(appName, subject, null, new HadoopConfiguration());
437 } finally {
438 t.setContextClassLoader(oldCCL);
439 }
440 }
441
442 private LoginContext getLogin() {
443 return user.getLogin();
444 }
445
446 private void setLogin(LoginContext login) {
447 user.setLogin(login);
448 }
449
450 /**
451 * Create a UserGroupInformation for the given subject.
452 * This does not change the subject or acquire new credentials.
453 * @param subject the user's subject
454 */
455 UserGroupInformation(Subject subject) {
456 this.subject = subject;
457 this.user = subject.getPrincipals(User.class).iterator().next();
458 this.isKeytab = !subject.getPrivateCredentials(KerberosKey.class).isEmpty();
459 this.isKrbTkt = !subject.getPrivateCredentials(KerberosTicket.class).isEmpty();
460 }
461
462 /**
463 * checks if logged in using kerberos
464 * @return true if the subject logged via keytab or has a Kerberos TGT
465 */
466 public boolean hasKerberosCredentials() {
467 return isKeytab || isKrbTkt;
468 }
469
470 /**
471 * Return the current user, including any doAs in the current stack.
472 * @return the current user
473 * @throws IOException if login fails
474 */
475 public synchronized
476 static UserGroupInformation getCurrentUser() throws IOException {
477 AccessControlContext context = AccessController.getContext();
478 Subject subject = Subject.getSubject(context);
479 if (subject == null || subject.getPrincipals(User.class).isEmpty()) {
480 return getLoginUser();
481 } else {
482 return new UserGroupInformation(subject);
483 }
484 }
485
486 /**
487 * Get the currently logged in user.
488 * @return the logged in user
489 * @throws IOException if login fails
490 */
491 public synchronized
492 static UserGroupInformation getLoginUser() throws IOException {
493 if (loginUser == null) {
494 try {
495 Subject subject = new Subject();
496 LoginContext login;
497 if (isSecurityEnabled()) {
498 login = newLoginContext(HadoopConfiguration.USER_KERBEROS_CONFIG_NAME,
499 subject);
500 } else {
501 login = newLoginContext(HadoopConfiguration.SIMPLE_CONFIG_NAME,
502 subject);
503 }
504 login.login();
505 loginUser = new UserGroupInformation(subject);
506 loginUser.setLogin(login);
507 loginUser.setAuthenticationMethod(isSecurityEnabled() ?
508 AuthenticationMethod.KERBEROS :
509 AuthenticationMethod.SIMPLE);
510 loginUser = new UserGroupInformation(login.getSubject());
511 String fileLocation = System.getenv(HADOOP_TOKEN_FILE_LOCATION);
512 if (fileLocation != null && isSecurityEnabled()) {
513 // load the token storage file and put all of the tokens into the
514 // user.
515 Credentials cred = Credentials.readTokenStorageFile(
516 new Path("file:///" + fileLocation), conf);
517 for (Token<?> token: cred.getAllTokens()) {
518 loginUser.addToken(token);
519 }
520 }
521 loginUser.spawnAutoRenewalThreadForUserCreds();
522 } catch (LoginException le) {
523 throw new IOException("failure to login", le);
524 }
525 if (LOG.isDebugEnabled()) {
526 LOG.debug("UGI loginUser:"+loginUser);
527 }
528 }
529 return loginUser;
530 }
531
532 /**
533 * Is this user logged in from a keytab file?
534 * @return true if the credentials are from a keytab file.
535 */
536 public boolean isFromKeytab() {
537 return isKeytab;
538 }
539
540 /**
541 * Get the Kerberos TGT
542 * @return the user's TGT or null if none was found
543 */
544 private synchronized KerberosTicket getTGT() {
545 Set<KerberosTicket> tickets = subject
546 .getPrivateCredentials(KerberosTicket.class);
547 for (KerberosTicket ticket : tickets) {
548 if (SecurityUtil.isOriginalTGT(ticket)) {
549 if (LOG.isDebugEnabled()) {
550 LOG.debug("Found tgt " + ticket);
551 }
552 return ticket;
553 }
554 }
555 return null;
556 }
557
558 private long getRefreshTime(KerberosTicket tgt) {
559 long start = tgt.getStartTime().getTime();
560 long end = tgt.getEndTime().getTime();
561 return start + (long) ((end - start) * TICKET_RENEW_WINDOW);
562 }
563
564 /**Spawn a thread to do periodic renewals of kerberos credentials*/
565 private void spawnAutoRenewalThreadForUserCreds() {
566 if (isSecurityEnabled()) {
567 //spawn thread only if we have kerb credentials
568 if (user.getAuthenticationMethod() == AuthenticationMethod.KERBEROS &&
569 !isKeytab) {
570 Thread t = new Thread(new Runnable() {
571
572 public void run() {
573 String cmd = conf.get("hadoop.kerberos.kinit.command",
574 "kinit");
575 KerberosTicket tgt = getTGT();
576 if (tgt == null) {
577 return;
578 }
579 long nextRefresh = getRefreshTime(tgt);
580 while (true) {
581 try {
582 long now = System.currentTimeMillis();
583 if(LOG.isDebugEnabled()) {
584 LOG.debug("Current time is " + now);
585 LOG.debug("Next refresh is " + nextRefresh);
586 }
587 if (now < nextRefresh) {
588 Thread.sleep(nextRefresh - now);
589 }
590 Shell.execCommand(cmd, "-R");
591 if(LOG.isDebugEnabled()) {
592 LOG.debug("renewed ticket");
593 }
594 reloginFromTicketCache();
595 tgt = getTGT();
596 if (tgt == null) {
597 LOG.warn("No TGT after renewal. Aborting renew thread for " +
598 getUserName());
599 return;
600 }
601 nextRefresh = Math.max(getRefreshTime(tgt),
602 now + MIN_TIME_BEFORE_RELOGIN);
603 } catch (InterruptedException ie) {
604 LOG.warn("Terminating renewal thread");
605 return;
606 } catch (IOException ie) {
607 LOG.warn("Exception encountered while running the" +
608 " renewal command. Aborting renew thread. " + ie);
609 return;
610 }
611 }
612 }
613 });
614 t.setDaemon(true);
615 t.setName("TGT Renewer for " + getUserName());
616 t.start();
617 }
618 }
619 }
620 /**
621 * Log a user in from a keytab file. Loads a user identity from a keytab
622 * file and logs them in. They become the currently logged-in user.
623 * @param user the principal name to load from the keytab
624 * @param path the path to the keytab file
625 * @throws IOException if the keytab file can't be read
626 */
627 public synchronized
628 static void loginUserFromKeytab(String user,
629 String path
630 ) throws IOException {
631 if (!isSecurityEnabled())
632 return;
633
634 keytabFile = path;
635 keytabPrincipal = user;
636 Subject subject = new Subject();
637 LoginContext login;
638 long start = 0;
639 try {
640 login =
641 newLoginContext(HadoopConfiguration.KEYTAB_KERBEROS_CONFIG_NAME, subject);
642 start = System.currentTimeMillis();
643 login.login();
644 metrics.loginSuccess.add(System.currentTimeMillis() - start);
645 loginUser = new UserGroupInformation(subject);
646 loginUser.setLogin(login);
647 loginUser.setAuthenticationMethod(AuthenticationMethod.KERBEROS);
648 } catch (LoginException le) {
649 if (start > 0) {
650 metrics.loginFailure.add(System.currentTimeMillis() - start);
651 }
652 throw new IOException("Login failure for " + user + " from keytab " +
653 path, le);
654 }
655 LOG.info("Login successful for user " + keytabPrincipal
656 + " using keytab file " + keytabFile);
657 }
658
659 /**
660 * Re-login a user from keytab if TGT is expired or is close to expiry.
661 *
662 * @throws IOException
663 */
664 public synchronized void checkTGTAndReloginFromKeytab() throws IOException {
665 if (!isSecurityEnabled()
666 || user.getAuthenticationMethod() != AuthenticationMethod.KERBEROS
667 || !isKeytab)
668 return;
669 KerberosTicket tgt = getTGT();
670 if (tgt != null && System.currentTimeMillis() < getRefreshTime(tgt)) {
671 return;
672 }
673 reloginFromKeytab();
674 }
675
676 /**
677 * Re-Login a user in from a keytab file. Loads a user identity from a keytab
678 * file and logs them in. They become the currently logged-in user. This
679 * method assumes that {@link #loginUserFromKeytab(String, String)} had
680 * happened already.
681 * The Subject field of this UserGroupInformation object is updated to have
682 * the new credentials.
683 * @throws IOException on a failure
684 */
685 public synchronized void reloginFromKeytab()
686 throws IOException {
687 if (!isSecurityEnabled() ||
688 user.getAuthenticationMethod() != AuthenticationMethod.KERBEROS ||
689 !isKeytab)
690 return;
691
692 long now = System.currentTimeMillis();
693 if (!hasSufficientTimeElapsed(now)) {
694 return;
695 }
696
697 KerberosTicket tgt = getTGT();
698 //Return if TGT is valid and is not going to expire soon.
699 if (tgt != null && now < getRefreshTime(tgt)) {
700 return;
701 }
702
703 LoginContext login = getLogin();
704 if (login == null || keytabFile == null) {
705 throw new IOException("loginUserFromKeyTab must be done first");
706 }
707
708 long start = 0;
709 // register most recent relogin attempt
710 user.setLastLogin(now);
711 try {
712 LOG.info("Initiating logout for " + getUserName());
713 synchronized (UserGroupInformation.class) {
714 // clear up the kerberos state. But the tokens are not cleared! As per
715 // the Java kerberos login module code, only the kerberos credentials
716 // are cleared
717 login.logout();
718 // login and also update the subject field of this instance to
719 // have the new credentials (pass it to the LoginContext constructor)
720 login = newLoginContext(
721 HadoopConfiguration.KEYTAB_KERBEROS_CONFIG_NAME, getSubject());
722 LOG.info("Initiating re-login for " + keytabPrincipal);
723 start = System.currentTimeMillis();
724 login.login();
725 metrics.loginSuccess.add(System.currentTimeMillis() - start);
726 setLogin(login);
727 }
728 } catch (LoginException le) {
729 if (start > 0) {
730 metrics.loginFailure.add(System.currentTimeMillis() - start);
731 }
732 throw new IOException("Login failure for " + keytabPrincipal +
733 " from keytab " + keytabFile, le);
734 }
735 }
736
737 /**
738 * Re-Login a user in from the ticket cache. This
739 * method assumes that login had happened already.
740 * The Subject field of this UserGroupInformation object is updated to have
741 * the new credentials.
742 * @throws IOException on a failure
743 */
744 public synchronized void reloginFromTicketCache()
745 throws IOException {
746 if (!isSecurityEnabled() ||
747 user.getAuthenticationMethod() != AuthenticationMethod.KERBEROS ||
748 !isKrbTkt)
749 return;
750 LoginContext login = getLogin();
751 if (login == null) {
752 throw new IOException("login must be done first");
753 }
754 long now = System.currentTimeMillis();
755 if (!hasSufficientTimeElapsed(now)) {
756 return;
757 }
758 // register most recent relogin attempt
759 user.setLastLogin(now);
760 try {
761 LOG.info("Initiating logout for " + getUserName());
762 //clear up the kerberos state. But the tokens are not cleared! As per
763 //the Java kerberos login module code, only the kerberos credentials
764 //are cleared
765 login.logout();
766 //login and also update the subject field of this instance to
767 //have the new credentials (pass it to the LoginContext constructor)
768 login =
769 newLoginContext(HadoopConfiguration.USER_KERBEROS_CONFIG_NAME,
770 getSubject());
771 LOG.info("Initiating re-login for " + getUserName());
772 login.login();
773 setLogin(login);
774 } catch (LoginException le) {
775 throw new IOException("Login failure for " + getUserName(), le);
776 }
777 }
778
779
780 /**
781 * Log a user in from a keytab file. Loads a user identity from a keytab
782 * file and login them in. This new user does not affect the currently
783 * logged-in user.
784 * @param user the principal name to load from the keytab
785 * @param path the path to the keytab file
786 * @throws IOException if the keytab file can't be read
787 */
788 public synchronized
789 static UserGroupInformation loginUserFromKeytabAndReturnUGI(String user,
790 String path
791 ) throws IOException {
792 if (!isSecurityEnabled())
793 return UserGroupInformation.getCurrentUser();
794 String oldKeytabFile = null;
795 String oldKeytabPrincipal = null;
796
797 long start = 0;
798 try {
799 oldKeytabFile = keytabFile;
800 oldKeytabPrincipal = keytabPrincipal;
801 keytabFile = path;
802 keytabPrincipal = user;
803 Subject subject = new Subject();
804
805 LoginContext login =
806 newLoginContext(HadoopConfiguration.KEYTAB_KERBEROS_CONFIG_NAME, subject);
807
808 start = System.currentTimeMillis();
809 login.login();
810 metrics.loginSuccess.add(System.currentTimeMillis() - start);
811 UserGroupInformation newLoginUser = new UserGroupInformation(subject);
812 newLoginUser.setLogin(login);
813 newLoginUser.setAuthenticationMethod(AuthenticationMethod.KERBEROS);
814
815 return newLoginUser;
816 } catch (LoginException le) {
817 if (start > 0) {
818 metrics.loginFailure.add(System.currentTimeMillis() - start);
819 }
820 throw new IOException("Login failure for " + user + " from keytab " +
821 path, le);
822 } finally {
823 if(oldKeytabFile != null) keytabFile = oldKeytabFile;
824 if(oldKeytabPrincipal != null) keytabPrincipal = oldKeytabPrincipal;
825 }
826 }
827
828 private boolean hasSufficientTimeElapsed(long now) {
829 if (now - user.getLastLogin() < MIN_TIME_BEFORE_RELOGIN ) {
830 LOG.warn("Not attempting to re-login since the last re-login was " +
831 "attempted less than " + (MIN_TIME_BEFORE_RELOGIN/1000) + " seconds"+
832 " before.");
833 return false;
834 }
835 return true;
836 }
837
838 /**
839 * Did the login happen via keytab
840 * @return true or false
841 */
842 public synchronized static boolean isLoginKeytabBased() throws IOException {
843 return getLoginUser().isKeytab;
844 }
845
846 /**
847 * Create a user from a login name. It is intended to be used for remote
848 * users in RPC, since it won't have any credentials.
849 * @param user the full user principal name, must not be empty or null
850 * @return the UserGroupInformation for the remote user.
851 */
852 public static UserGroupInformation createRemoteUser(String user) {
853 if (user == null || "".equals(user)) {
854 throw new IllegalArgumentException("Null user");
855 }
856 Subject subject = new Subject();
857 subject.getPrincipals().add(new User(user));
858 UserGroupInformation result = new UserGroupInformation(subject);
859 result.setAuthenticationMethod(AuthenticationMethod.SIMPLE);
860 return result;
861 }
862
863 /**
864 * existing types of authentications' methods
865 */
866 @InterfaceStability.Evolving
867 public static enum AuthenticationMethod {
868 SIMPLE,
869 KERBEROS,
870 TOKEN,
871 CERTIFICATE,
872 KERBEROS_SSL,
873 PROXY;
874 }
875
876 /**
877 * Create a proxy user using username of the effective user and the ugi of the
878 * real user.
879 * @param user
880 * @param realUser
881 * @return proxyUser ugi
882 */
883 public static UserGroupInformation createProxyUser(String user,
884 UserGroupInformation realUser) {
885 if (user == null || "".equals(user)) {
886 throw new IllegalArgumentException("Null user");
887 }
888 if (realUser == null) {
889 throw new IllegalArgumentException("Null real user");
890 }
891 Subject subject = new Subject();
892 Set<Principal> principals = subject.getPrincipals();
893 principals.add(new User(user));
894 principals.add(new RealUser(realUser));
895 UserGroupInformation result =new UserGroupInformation(subject);
896 result.setAuthenticationMethod(AuthenticationMethod.PROXY);
897 return result;
898 }
899
900 /**
901 * get RealUser (vs. EffectiveUser)
902 * @return realUser running over proxy user
903 */
904 public UserGroupInformation getRealUser() {
905 for (RealUser p: subject.getPrincipals(RealUser.class)) {
906 return p.getRealUser();
907 }
908 return null;
909 }
910
911
912
913 /**
914 * This class is used for storing the groups for testing. It stores a local
915 * map that has the translation of usernames to groups.
916 */
917 private static class TestingGroups extends Groups {
918 private final Map<String, List<String>> userToGroupsMapping =
919 new HashMap<String,List<String>>();
920 private Groups underlyingImplementation;
921
922 private TestingGroups(Groups underlyingImplementation) {
923 super(new org.apache.hadoop.conf.Configuration());
924 this.underlyingImplementation = underlyingImplementation;
925 }
926
927 @Override
928 public List<String> getGroups(String user) throws IOException {
929 List<String> result = userToGroupsMapping.get(user);
930
931 if (result == null) {
932 result = underlyingImplementation.getGroups(user);
933 }
934
935 return result;
936 }
937
938 private void setUserGroups(String user, String[] groups) {
939 userToGroupsMapping.put(user, Arrays.asList(groups));
940 }
941 }
942
943 /**
944 * Create a UGI for testing HDFS and MapReduce
945 * @param user the full user principal name
946 * @param userGroups the names of the groups that the user belongs to
947 * @return a fake user for running unit tests
948 */
949 @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
950 public static UserGroupInformation createUserForTesting(String user,
951 String[] userGroups) {
952 ensureInitialized();
953 UserGroupInformation ugi = createRemoteUser(user);
954 // make sure that the testing object is setup
955 if (!(groups instanceof TestingGroups)) {
956 groups = new TestingGroups(groups);
957 }
958 // add the user groups
959 ((TestingGroups) groups).setUserGroups(ugi.getShortUserName(), userGroups);
960 return ugi;
961 }
962
963
964 /**
965 * Create a proxy user UGI for testing HDFS and MapReduce
966 *
967 * @param user
968 * the full user principal name for effective user
969 * @param realUser
970 * UGI of the real user
971 * @param userGroups
972 * the names of the groups that the user belongs to
973 * @return a fake user for running unit tests
974 */
975 @InterfaceAudience.LimitedPrivate( { "HDFS", "MapReduce" })
976 public static UserGroupInformation createProxyUserForTesting(String user,
977 UserGroupInformation realUser, String[] userGroups) {
978 ensureInitialized();
979 UserGroupInformation ugi = createProxyUser(user, realUser);
980 // make sure that the testing object is setup
981 if (!(groups instanceof TestingGroups)) {
982 groups = new TestingGroups(groups);
983 }
984 // add the user groups
985 ((TestingGroups) groups).setUserGroups(ugi.getShortUserName(), userGroups);
986 return ugi;
987 }
988
989 /**
990 * Get the user's login name.
991 * @return the user's name up to the first '/' or '@'.
992 */
993 public String getShortUserName() {
994 for (User p: subject.getPrincipals(User.class)) {
995 return p.getShortName();
996 }
997 return null;
998 }
999
1000 /**
1001 * Get the user's full principal name.
1002 * @return the user's full principal name.
1003 */
1004 public String getUserName() {
1005 return user.getName();
1006 }
1007
1008 /**
1009 * Add a TokenIdentifier to this UGI. The TokenIdentifier has typically been
1010 * authenticated by the RPC layer as belonging to the user represented by this
1011 * UGI.
1012 *
1013 * @param tokenId
1014 * tokenIdentifier to be added
1015 * @return true on successful add of new tokenIdentifier
1016 */
1017 public synchronized boolean addTokenIdentifier(TokenIdentifier tokenId) {
1018 return subject.getPublicCredentials().add(tokenId);
1019 }
1020
1021 /**
1022 * Get the set of TokenIdentifiers belonging to this UGI
1023 *
1024 * @return the set of TokenIdentifiers belonging to this UGI
1025 */
1026 public synchronized Set<TokenIdentifier> getTokenIdentifiers() {
1027 return subject.getPublicCredentials(TokenIdentifier.class);
1028 }
1029
1030 /**
1031 * Add a token to this UGI
1032 *
1033 * @param token Token to be added
1034 * @return true on successful add of new token
1035 */
1036 public synchronized boolean addToken(Token<? extends TokenIdentifier> token) {
1037 return subject.getPrivateCredentials().add(token);
1038 }
1039
1040 /**
1041 * Obtain the collection of tokens associated with this user.
1042 *
1043 * @return an unmodifiable collection of tokens associated with user
1044 */
1045 public synchronized
1046 Collection<Token<? extends TokenIdentifier>> getTokens() {
1047 Set<Object> creds = subject.getPrivateCredentials();
1048 List<Token<?>> result = new ArrayList<Token<?>>(creds.size());
1049 for(Object o: creds) {
1050 if (o instanceof Token<?>) {
1051 result.add((Token<?>) o);
1052 }
1053 }
1054 return Collections.unmodifiableList(result);
1055 }
1056
1057 /**
1058 * Get the group names for this user.
1059 * @return the list of users with the primary group first. If the command
1060 * fails, it returns an empty list.
1061 */
1062 public synchronized String[] getGroupNames() {
1063 ensureInitialized();
1064 try {
1065 List<String> result = groups.getGroups(getShortUserName());
1066 return result.toArray(new String[result.size()]);
1067 } catch (IOException ie) {
1068 LOG.warn("No groups available for user " + getShortUserName());
1069 return new String[0];
1070 }
1071 }
1072
1073 /**
1074 * Return the username.
1075 */
1076 @Override
1077 public String toString() {
1078 StringBuilder sb = new StringBuilder(getUserName());
1079 sb.append(" (auth:"+getAuthenticationMethod()+")");
1080 if (getRealUser() != null) {
1081 sb.append(" via ").append(getRealUser().toString());
1082 }
1083 return sb.toString();
1084 }
1085
1086 /**
1087 * Sets the authentication method in the subject
1088 *
1089 * @param authMethod
1090 */
1091 public synchronized
1092 void setAuthenticationMethod(AuthenticationMethod authMethod) {
1093 user.setAuthenticationMethod(authMethod);
1094 }
1095
1096 /**
1097 * Get the authentication method from the subject
1098 *
1099 * @return AuthenticationMethod in the subject, null if not present.
1100 */
1101 public synchronized AuthenticationMethod getAuthenticationMethod() {
1102 return user.getAuthenticationMethod();
1103 }
1104
1105 /**
1106 * Returns the authentication method of a ugi. If the authentication method is
1107 * PROXY, returns the authentication method of the real user.
1108 *
1109 * @param ugi
1110 * @return AuthenticationMethod
1111 */
1112 public static AuthenticationMethod getRealAuthenticationMethod(
1113 UserGroupInformation ugi) {
1114 AuthenticationMethod authMethod = ugi.getAuthenticationMethod();
1115 if (authMethod == AuthenticationMethod.PROXY) {
1116 authMethod = ugi.getRealUser().getAuthenticationMethod();
1117 }
1118 return authMethod;
1119 }
1120
1121 /**
1122 * Compare the subjects to see if they are equal to each other.
1123 */
1124 @Override
1125 public boolean equals(Object o) {
1126 if (o == this) {
1127 return true;
1128 } else if (o == null || getClass() != o.getClass()) {
1129 return false;
1130 } else {
1131 return subject == ((UserGroupInformation) o).subject;
1132 }
1133 }
1134
1135 /**
1136 * Return the hash of the subject.
1137 */
1138 @Override
1139 public int hashCode() {
1140 return System.identityHashCode(subject);
1141 }
1142
1143 /**
1144 * Get the underlying subject from this ugi.
1145 * @return the subject that represents this user.
1146 */
1147 protected Subject getSubject() {
1148 return subject;
1149 }
1150
1151 /**
1152 * Run the given action as the user.
1153 * @param <T> the return type of the run method
1154 * @param action the method to execute
1155 * @return the value from the run method
1156 */
1157 public <T> T doAs(PrivilegedAction<T> action) {
1158 logPrivilegedAction(subject, action);
1159 return Subject.doAs(subject, action);
1160 }
1161
1162 /**
1163 * Run the given action as the user, potentially throwing an exception.
1164 * @param <T> the return type of the run method
1165 * @param action the method to execute
1166 * @return the value from the run method
1167 * @throws IOException if the action throws an IOException
1168 * @throws Error if the action throws an Error
1169 * @throws RuntimeException if the action throws a RuntimeException
1170 * @throws InterruptedException if the action throws an InterruptedException
1171 * @throws UndeclaredThrowableException if the action throws something else
1172 */
1173 public <T> T doAs(PrivilegedExceptionAction<T> action
1174 ) throws IOException, InterruptedException {
1175 try {
1176 logPrivilegedAction(subject, action);
1177 return Subject.doAs(subject, action);
1178 } catch (PrivilegedActionException pae) {
1179 Throwable cause = pae.getCause();
1180 LOG.error("PriviledgedActionException as:"+this+" cause:"+cause);
1181 if (cause instanceof IOException) {
1182 throw (IOException) cause;
1183 } else if (cause instanceof Error) {
1184 throw (Error) cause;
1185 } else if (cause instanceof RuntimeException) {
1186 throw (RuntimeException) cause;
1187 } else if (cause instanceof InterruptedException) {
1188 throw (InterruptedException) cause;
1189 } else {
1190 throw new UndeclaredThrowableException(pae,"Unknown exception in doAs");
1191 }
1192 }
1193 }
1194
1195 private void logPrivilegedAction(Subject subject, Object action) {
1196 if (LOG.isDebugEnabled()) {
1197 // would be nice if action included a descriptive toString()
1198 String where = new Throwable().getStackTrace()[2].toString();
1199 LOG.debug("PrivilegedAction as:"+this+" from:"+where);
1200 }
1201 }
1202
1203 private void print() throws IOException {
1204 System.out.println("User: " + getUserName());
1205 System.out.print("Group Ids: ");
1206 System.out.println();
1207 String[] groups = getGroupNames();
1208 System.out.print("Groups: ");
1209 for(int i=0; i < groups.length; i++) {
1210 System.out.print(groups[i] + " ");
1211 }
1212 System.out.println();
1213 }
1214
1215 /**
1216 * A test method to print out the current user's UGI.
1217 * @param args if there are two arguments, read the user from the keytab
1218 * and print it out.
1219 * @throws Exception
1220 */
1221 public static void main(String [] args) throws Exception {
1222 System.out.println("Getting UGI for current user");
1223 UserGroupInformation ugi = getCurrentUser();
1224 ugi.print();
1225 System.out.println("UGI: " + ugi);
1226 System.out.println("Auth method " + ugi.user.getAuthenticationMethod());
1227 System.out.println("Keytab " + ugi.isKeytab);
1228 System.out.println("============================================================");
1229
1230 if (args.length == 2) {
1231 System.out.println("Getting UGI from keytab....");
1232 loginUserFromKeytab(args[0], args[1]);
1233 getCurrentUser().print();
1234 System.out.println("Keytab: " + ugi);
1235 System.out.println("Auth method " + loginUser.user.getAuthenticationMethod());
1236 System.out.println("Keytab " + loginUser.isKeytab);
1237 }
1238 }
1239
1240 }