hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/TestUGILoginFromKeytab.java - hadoop - Git at Google

 /**
  * 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 org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.minikdc.MiniKdc;
 import org.apache.hadoop.security.UserGroupInformation.AuthenticationMethod;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.Time;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 import org.mockito.Mockito;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 import org.slf4j.event.Level;

 import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED;
 import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_KERBEROS_MIN_SECONDS_BEFORE_RELOGIN;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;

 import java.io.File;
 import java.io.IOException;
 import java.security.Principal;
 import java.security.PrivilegedExceptionAction;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CyclicBarrier;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;

 import javax.security.auth.Subject;
 import javax.security.auth.kerberos.KerberosPrincipal;
 import javax.security.auth.kerberos.KerberosTicket;
 import javax.security.auth.login.LoginContext;

 /**
  * Verify UGI login from keytab. Check that the UGI is
  * configured to use keytab to catch regressions like
  * HADOOP-10786.
  */
 public class TestUGILoginFromKeytab {

   private MiniKdc kdc;
   private File workDir;
   private ExecutorService executor;

   @Rule
   public final TemporaryFolder folder = new TemporaryFolder();

   @Before
   public void startMiniKdc() throws Exception {
     // This setting below is required. If not enabled, UGI will abort
     // any attempt to loginUserFromKeytab.
     Configuration conf = new Configuration();
     conf.set(CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION,
         "kerberos");
     UserGroupInformation.setConfiguration(conf);
     UserGroupInformation.setShouldRenewImmediatelyForTests(true);
     workDir = folder.getRoot();
     kdc = new MiniKdc(MiniKdc.createConf(), workDir);
     kdc.start();
     executor = Executors.newCachedThreadPool();

   }

   @After
   public void stopMiniKdc() {
     if (kdc != null) {
       kdc.stop();
     }
     if (executor != null) {
       executor.shutdownNow();
     }
   }

   /**
    * Login from keytab using the MiniKDC.
    */
   @Test
   public void testUGILoginFromKeytab() throws Exception {
     long beforeLogin = Time.now();
     String principal = "foo";
     File keytab = new File(workDir, "foo.keytab");
     kdc.createPrincipal(keytab, principal);

     UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());
     UserGroupInformation ugi = UserGroupInformation.getLoginUser();
     Assert.assertTrue("UGI should be configured to login from keytab",
         ugi.isFromKeytab());

     User user = getUser(ugi.getSubject());
     Assert.assertNotNull(user.getLogin());

     Assert.assertTrue("User login time is less than before login time, "
         + "beforeLoginTime:" + beforeLogin + " userLoginTime:" + user.getLastLogin(),
             user.getLastLogin() > beforeLogin);
   }

   /**
    * Login from keytab using the MiniKDC and verify the UGI can successfully
    * relogin from keytab as well. This will catch regressions like HADOOP-10786.
    */
   @Test
   public void testUGIReLoginFromKeytab() throws Exception {
     String principal = "foo";
     File keytab = new File(workDir, "foo.keytab");
     kdc.createPrincipal(keytab, principal);

     UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());
     UserGroupInformation ugi = UserGroupInformation.getLoginUser();
     Assert.assertTrue("UGI should be configured to login from keytab",
         ugi.isFromKeytab());

     // Verify relogin from keytab.
     User user = getUser(ugi.getSubject());
     final long firstLogin = user.getLastLogin();
     final LoginContext login1 = user.getLogin();
     Assert.assertNotNull(login1);

     // Sleep for 2 secs to have a difference between first and second login
     Thread.sleep(2000);

     ugi.reloginFromKeytab();
     final long secondLogin = user.getLastLogin();
     final LoginContext login2 = user.getLogin();
     Assert.assertTrue("User should have been able to relogin from keytab",
         secondLogin > firstLogin);
     Assert.assertNotNull(login2);
     Assert.assertNotSame(login1, login2);
   }

   @Test
   public void testGetUGIFromKnownSubject() throws Exception {
     KerberosPrincipal principal = new KerberosPrincipal("user");
     File keytab = new File(workDir, "user.keytab");
     kdc.createPrincipal(keytab, principal.getName());

     UserGroupInformation ugi1 =
       UserGroupInformation.loginUserFromKeytabAndReturnUGI(
         principal.getName(), keytab.getPath());
     Subject subject = ugi1.getSubject();
     User user = getUser(subject);
     Assert.assertNotNull(user);
     LoginContext login = user.getLogin();
     Assert.assertNotNull(login);

     // User instance and/or login context should not change.
     UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
     Assert.assertSame(user, getUser(ugi2.getSubject()));
     Assert.assertSame(login, user.getLogin());
   }

   @Test
   public void testGetUGIFromExternalSubject() throws Exception {
     KerberosPrincipal principal = new KerberosPrincipal("user");
     File keytab = new File(workDir, "user.keytab");
     kdc.createPrincipal(keytab, principal.getName());

     UserGroupInformation ugi =
       UserGroupInformation.loginUserFromKeytabAndReturnUGI(
         principal.getName(), keytab.getPath());
     Subject subject = ugi.getSubject();
     removeUser(subject);

     // first call to get the ugi should add the User instance w/o a login
     // context.
     UserGroupInformation ugi1 = UserGroupInformation.getUGIFromSubject(subject);
     Assert.assertSame(subject, ugi1.getSubject());
     User user = getUser(subject);
     Assert.assertNotNull(user);
     Assert.assertEquals(principal.getName(), user.getName());
     Assert.assertNull(user.getLogin());

     // subsequent call should not change the existing User instance.
     UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
     Assert.assertSame(subject, ugi2.getSubject());
     Assert.assertSame(user, getUser(ugi2.getSubject()));
     Assert.assertNull(user.getLogin());
   }

   @Test
   public void testGetUGIFromExternalSubjectWithLogin() throws Exception {
     KerberosPrincipal principal = new KerberosPrincipal("user");
     File keytab = new File(workDir, "user.keytab");
     kdc.createPrincipal(keytab, principal.getName());

     // alter the User's login context to appear to be a foreign and
     // unmanagable context.
     UserGroupInformation ugi =
       UserGroupInformation.loginUserFromKeytabAndReturnUGI(
         principal.getName(), keytab.getPath());
     Subject subject = ugi.getSubject();
     User user = getUser(subject);
     final LoginContext dummyLogin = Mockito.mock(LoginContext.class);
     user.setLogin(dummyLogin);

     // nothing should change.
     UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
     Assert.assertSame(subject, ugi2.getSubject());
     Assert.assertSame(user, getUser(ugi2.getSubject()));
     Assert.assertSame(dummyLogin, user.getLogin());
   }

   @Test
   public void testUGIRefreshFromKeytab() throws Exception {
     final Configuration conf = new Configuration();
     conf.setBoolean(HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED, true);
     SecurityUtil.setAuthenticationMethod(
             UserGroupInformation.AuthenticationMethod.KERBEROS, conf);
     UserGroupInformation.setConfiguration(conf);

     String principal = "bar";
     File keytab = new File(workDir, "bar.keytab");
     kdc.createPrincipal(keytab, principal);

     UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());

     UserGroupInformation ugi = UserGroupInformation.getLoginUser();

     Assert.assertEquals(UserGroupInformation.AuthenticationMethod.KERBEROS,
         ugi.getAuthenticationMethod());
     Assert.assertTrue(ugi.isFromKeytab());
     Assert.assertTrue(
             UserGroupInformation.isKerberosKeyTabLoginRenewalEnabled());
     Assert.assertTrue(
             UserGroupInformation.getKerberosLoginRenewalExecutor()
                     .isPresent());
   }

   @Test
   public void testUGIRefreshFromKeytabDisabled() throws Exception {
     GenericTestUtils.setLogLevel(UserGroupInformation.LOG, Level.DEBUG);
     final Configuration conf = new Configuration();
     conf.setLong(HADOOP_KERBEROS_MIN_SECONDS_BEFORE_RELOGIN, 1);
     conf.setBoolean(HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED, false);
     SecurityUtil.setAuthenticationMethod(
             UserGroupInformation.AuthenticationMethod.KERBEROS, conf);
     UserGroupInformation.setConfiguration(conf);

     String principal = "bar";
     File keytab = new File(workDir, "bar.keytab");
     kdc.createPrincipal(keytab, principal);

     UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());

     UserGroupInformation ugi = UserGroupInformation.getLoginUser();
     Assert.assertEquals(UserGroupInformation.AuthenticationMethod.KERBEROS,
             ugi.getAuthenticationMethod());
     Assert.assertTrue(ugi.isFromKeytab());
     Assert.assertFalse(
             UserGroupInformation.isKerberosKeyTabLoginRenewalEnabled());
     Assert.assertFalse(
             UserGroupInformation.getKerberosLoginRenewalExecutor()
                     .isPresent());
   }

   private static KerberosTicket getTicket(UserGroupInformation ugi) {
     Set<KerberosTicket> tickets =
         ugi.getSubject().getPrivateCredentials(KerberosTicket.class);
     return tickets.isEmpty() ? null : tickets.iterator().next();
   }

   // verify ugi has expected principal, a keytab, and has a ticket for
   // the expected principal.
   private static KerberosTicket checkTicketAndKeytab(UserGroupInformation ugi,
       KerberosPrincipal principal, boolean expectIsKeytab) {
     Assert.assertEquals("wrong principal",
       principal.getName(), ugi.getUserName());
     Assert.assertEquals("is not keytab",
       expectIsKeytab, ugi.isFromKeytab());
     KerberosTicket ticket = getTicket(ugi);
     Assert.assertNotNull("no ticket", ticket);
     Assert.assertEquals("wrong principal", principal, ticket.getClient());
     return ticket;
   }

   @Test
   public void testReloginForUGIFromSubject() throws Exception {
     KerberosPrincipal principal1 = new KerberosPrincipal("user1");
     File keytab1 = new File(workDir, "user1.keytab");
     kdc.createPrincipal(keytab1, principal1.getName());

     KerberosPrincipal principal2 = new KerberosPrincipal("user2");
     File keytab2 = new File(workDir, "user2.keytab");
     kdc.createPrincipal(keytab2, principal2.getName());

     // Login a user and remove the User instance so it looks like an
     // "external" subject.
     final Subject extSubject =
       UserGroupInformation.loginUserFromKeytabAndReturnUGI(
         principal2.getName(), keytab2.getPath()).getSubject();
     removeUser(extSubject);

     // Login another user.
     UserGroupInformation.loginUserFromKeytab(
         principal1.getName(), keytab1.getPath());
     final UserGroupInformation loginUser = UserGroupInformation.getLoginUser();

     loginUser.doAs(new PrivilegedExceptionAction<Void>() {
       @Override
       public Void run() throws IOException {
         KerberosTicket loginTicket =
             checkTicketAndKeytab(loginUser, principal1, true);

         // get the ugi for the previously logged in subject.
         UserGroupInformation extSubjectUser =
             UserGroupInformation.getUGIFromSubject(extSubject);
         KerberosTicket ticket =
           checkTicketAndKeytab(extSubjectUser, principal2, false);

         // verify login user got a new ticket.
         loginUser.reloginFromKeytab();
         KerberosTicket newLoginTicket =
             checkTicketAndKeytab(loginUser, principal1, true);
         Assert.assertNotEquals(loginTicket.getAuthTime(),
             newLoginTicket.getAuthTime());

         // verify an "external" subject ticket does not change.
         extSubjectUser.reloginFromKeytab();
         Assert.assertSame(ticket,
             checkTicketAndKeytab(extSubjectUser, principal2, false));

         // verify subject ugi relogin did not affect the login user.
         Assert.assertSame(newLoginTicket,
             checkTicketAndKeytab(loginUser, principal1, true));

         return null;
       }
     });
   }

   @Test
   public void testReloginForLoginFromSubject() throws Exception {
     KerberosPrincipal principal1 = new KerberosPrincipal("user1");
     File keytab1 = new File(workDir, "user1.keytab");
     kdc.createPrincipal(keytab1, principal1.getName());

     KerberosPrincipal principal2 = new KerberosPrincipal("user2");
     File keytab2 = new File(workDir, "user2.keytab");
     kdc.createPrincipal(keytab2, principal2.getName());

     // login principal1 with a keytab.
     UserGroupInformation.loginUserFromKeytab(
         principal1.getName(), keytab1.getPath());
     final UserGroupInformation originalLoginUser =
         UserGroupInformation.getLoginUser();
     Assert.assertNotNull(getUser(originalLoginUser.getSubject()).getLogin());

     originalLoginUser.doAs(new PrivilegedExceptionAction<Void>() {
       @Override
       public Void run() throws IOException {
         KerberosTicket originalLoginUserTicket =
             checkTicketAndKeytab(originalLoginUser, principal1, true);

         // login principal2 from a subject with keytab.  it's external so
         // no login context should be attached to the user.
         final Subject subject =
           UserGroupInformation.loginUserFromKeytabAndReturnUGI(
             principal2.getName(), keytab2.getPath()).getSubject();
         removeUser(subject);

         // verify the new login user is external.
         UserGroupInformation.loginUserFromSubject(subject);
         Assert.assertNull(getUser(subject).getLogin());
         UserGroupInformation extLoginUser =
           UserGroupInformation.getLoginUser();
         KerberosTicket extLoginUserTicket =
             checkTicketAndKeytab(extLoginUser, principal2, false);

         // verify subject-based login user does not get a new ticket, and
         // original login user not affected.
         extLoginUser.reloginFromKeytab();
         Assert.assertSame(extLoginUserTicket,
           checkTicketAndKeytab(extLoginUser, principal2, false));
         Assert.assertSame(originalLoginUserTicket,
           checkTicketAndKeytab(originalLoginUser, principal1, true));

         // verify original login user gets a new ticket, new login user
         // not affected.
         originalLoginUser.reloginFromKeytab();
         Assert.assertNotSame(originalLoginUserTicket,
             checkTicketAndKeytab(originalLoginUser, principal1, true));
         Assert.assertSame(extLoginUserTicket,
             checkTicketAndKeytab(extLoginUser, principal2, false));
         return null;
       }
     });
   }

   @Test
   public void testReloginAfterFailedRelogin() throws Exception {
     KerberosPrincipal principal = new KerberosPrincipal("user1");
     File keytab = new File(workDir, "user1.keytab");
     File keytabBackup = new File(keytab + ".backup");
     kdc.createPrincipal(keytab, principal.getName());

     UserGroupInformation.loginUserFromKeytab(
         principal.getName(), keytab.getPath());
     final UserGroupInformation loginUser = UserGroupInformation.getLoginUser();
     checkTicketAndKeytab(loginUser, principal, true);

     // move the keytab to induce a relogin failure.
     Assert.assertTrue(keytab.renameTo(keytabBackup));
     try {
       loginUser.reloginFromKeytab();
       Assert.fail("relogin should fail");
     } catch (KerberosAuthException kae) {
       // expected.
     }

     // even though no KeyTab object, ugi should know it's keytab based.
     Assert.assertTrue(loginUser.isFromKeytab());
     Assert.assertNull(getTicket(loginUser));

     // move keytab back to enable relogin to succeed.
     Assert.assertTrue(keytabBackup.renameTo(keytab));
     loginUser.reloginFromKeytab();
     checkTicketAndKeytab(loginUser, principal, true);
   }

   // verify getting concurrent relogins blocks to avoid indeterminate
   // credentials corruption, but getting a ugi for the subject does not block.
   @Test(timeout=180000)
   public void testConcurrentRelogin() throws Exception {
     final CyclicBarrier barrier = new CyclicBarrier(2);
     final CountDownLatch latch = new CountDownLatch(1);
     assertTrue(UserGroupInformation.isSecurityEnabled());

     KerberosPrincipal principal = new KerberosPrincipal("testUser");
     File keytab = new File(workDir, "user1.keytab");
     kdc.createPrincipal(keytab, principal.getName());

     // create a keytab ugi.
     final UserGroupInformation loginUgi =
         UserGroupInformation.loginUserFromKeytabAndReturnUGI(
           principal.getName(), keytab.getPath());
     assertEquals(AuthenticationMethod.KERBEROS,
         loginUgi.getAuthenticationMethod());
     assertTrue(loginUgi.isFromKeytab());

     // create a new ugi instance based on subject from the logged in user.
     final UserGroupInformation clonedUgi =
         UserGroupInformation.getUGIFromSubject(loginUgi.getSubject());
     assertEquals(AuthenticationMethod.KERBEROS,
         clonedUgi.getAuthenticationMethod());
     assertTrue(clonedUgi.isFromKeytab());

     // cause first relogin to block on a barrier in logout to verify relogins
     // are atomic.
     User user = getUser(loginUgi.getSubject());
     final LoginContext spyLogin = Mockito.spy(user.getLogin());
     user.setLogin(spyLogin);
     Mockito.doAnswer(new Answer<Void>(){
       @Override
       public Void answer(InvocationOnMock invocation)
           throws Throwable {
         invocation.callRealMethod();
         latch.countDown();
         barrier.await();
         return null;
       }
     }).when(spyLogin).logout();

     Future<Void> relogin = executor.submit(
         new Callable<Void>(){
           @Override
           public Void call() throws Exception {
             Thread.currentThread().setName("relogin");
             loginUgi.reloginFromKeytab();
             return null;
           }
         });
     // wait for the thread to block on the barrier in the logout of the
     // relogin.
     assertTrue("first relogin didn't block",
       latch.await(2, TimeUnit.SECONDS));

     // although the logout removed the keytab instance, verify the ugi
     // knows from its login params that it is supposed to be from a keytab.
     assertTrue(clonedUgi.isFromKeytab());

     // another concurrent re-login should block.
     Mockito.doNothing().when(spyLogin).logout();
     Mockito.doNothing().when(spyLogin).login();
     Future<UserGroupInformation> clonedRelogin = executor.submit(
         new Callable<UserGroupInformation>(){
           @Override
           public UserGroupInformation call() throws Exception {
             Thread.currentThread().setName("clonedRelogin");
             clonedUgi.reloginFromKeytab();
             return clonedUgi;
           }
         });

     try {
       clonedRelogin.get(2, TimeUnit.SECONDS);
       fail("second relogin didn't block!");
     } catch (TimeoutException te) {
       // expected
     }

     // concurrent UGI instantiation should not block and again should
     // know it's supposed to be from a keytab.
     loginUgi.doAs(new PrivilegedExceptionAction<Void>(){
       @Override
       public Void run() throws Exception {
         UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
         assertEquals(principal.getName(), ugi.getUserName());
         assertTrue(ugi.isFromKeytab());
         return null;
       }
     });
     clonedUgi.doAs(new PrivilegedExceptionAction<Void>(){
       @Override
       public Void run() throws Exception {
         UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
         assertEquals(principal.getName(), ugi.getUserName());
         assertTrue(ugi.isFromKeytab());
         return null;
       }
     });

     // second relogin should still be blocked until the original relogin
     // is blocked.
     assertFalse(clonedRelogin.isDone());
     barrier.await();
     relogin.get();
     clonedRelogin.get();
   }

   private User getUser(Subject subject) {
     Iterator<User> iter = subject.getPrincipals(User.class).iterator();
     return iter.hasNext() ? iter.next() : null;
   }

   private void removeUser(Subject subject) {
     // remove User instance so it appears to not be logged in.
     for (Iterator<Principal> iter = subject.getPrincipals().iterator();
          iter.hasNext(); ) {
       if (iter.next() instanceof User) {
         iter.remove();
       }
     }
   }
 }
	/**
	* 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 org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.fs.CommonConfigurationKeys;
	import org.apache.hadoop.minikdc.MiniKdc;
	import org.apache.hadoop.security.UserGroupInformation.AuthenticationMethod;
	import org.apache.hadoop.test.GenericTestUtils;
	import org.apache.hadoop.util.Time;
	import org.junit.After;
	import org.junit.Assert;
	import org.junit.Before;
	import org.junit.Rule;
	import org.junit.Test;
	import org.junit.rules.TemporaryFolder;
	import org.mockito.Mockito;
	import org.mockito.invocation.InvocationOnMock;
	import org.mockito.stubbing.Answer;
	import org.slf4j.event.Level;

	import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED;
	import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_KERBEROS_MIN_SECONDS_BEFORE_RELOGIN;
	import static org.junit.Assert.assertEquals;
	import static org.junit.Assert.assertFalse;
	import static org.junit.Assert.assertTrue;
	import static org.junit.Assert.fail;

	import java.io.File;
	import java.io.IOException;
	import java.security.Principal;
	import java.security.PrivilegedExceptionAction;
	import java.util.Iterator;
	import java.util.Set;
	import java.util.concurrent.Callable;
	import java.util.concurrent.CountDownLatch;
	import java.util.concurrent.CyclicBarrier;
	import java.util.concurrent.ExecutorService;
	import java.util.concurrent.Executors;
	import java.util.concurrent.Future;
	import java.util.concurrent.TimeUnit;
	import java.util.concurrent.TimeoutException;

	import javax.security.auth.Subject;
	import javax.security.auth.kerberos.KerberosPrincipal;
	import javax.security.auth.kerberos.KerberosTicket;
	import javax.security.auth.login.LoginContext;

	/**
	* Verify UGI login from keytab. Check that the UGI is
	* configured to use keytab to catch regressions like
	* HADOOP-10786.
	*/
	public class TestUGILoginFromKeytab {

	private MiniKdc kdc;
	private File workDir;
	private ExecutorService executor;

	@Rule
	public final TemporaryFolder folder = new TemporaryFolder();

	@Before
	public void startMiniKdc() throws Exception {
	// This setting below is required. If not enabled, UGI will abort
	// any attempt to loginUserFromKeytab.
	Configuration conf = new Configuration();
	conf.set(CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION,
	"kerberos");
	UserGroupInformation.setConfiguration(conf);
	UserGroupInformation.setShouldRenewImmediatelyForTests(true);
	workDir = folder.getRoot();
	kdc = new MiniKdc(MiniKdc.createConf(), workDir);
	kdc.start();
	executor = Executors.newCachedThreadPool();

	}

	@After
	public void stopMiniKdc() {
	if (kdc != null) {
	kdc.stop();
	}
	if (executor != null) {
	executor.shutdownNow();
	}
	}

	/**
	* Login from keytab using the MiniKDC.
	*/
	@Test
	public void testUGILoginFromKeytab() throws Exception {
	long beforeLogin = Time.now();
	String principal = "foo";
	File keytab = new File(workDir, "foo.keytab");
	kdc.createPrincipal(keytab, principal);

	UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());
	UserGroupInformation ugi = UserGroupInformation.getLoginUser();
	Assert.assertTrue("UGI should be configured to login from keytab",
	ugi.isFromKeytab());

	User user = getUser(ugi.getSubject());
	Assert.assertNotNull(user.getLogin());

	Assert.assertTrue("User login time is less than before login time, "
	+ "beforeLoginTime:" + beforeLogin + " userLoginTime:" + user.getLastLogin(),
	user.getLastLogin() > beforeLogin);
	}

	/**
	* Login from keytab using the MiniKDC and verify the UGI can successfully
	* relogin from keytab as well. This will catch regressions like HADOOP-10786.
	*/
	@Test
	public void testUGIReLoginFromKeytab() throws Exception {
	String principal = "foo";
	File keytab = new File(workDir, "foo.keytab");
	kdc.createPrincipal(keytab, principal);

	UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());
	UserGroupInformation ugi = UserGroupInformation.getLoginUser();
	Assert.assertTrue("UGI should be configured to login from keytab",
	ugi.isFromKeytab());

	// Verify relogin from keytab.
	User user = getUser(ugi.getSubject());
	final long firstLogin = user.getLastLogin();
	final LoginContext login1 = user.getLogin();
	Assert.assertNotNull(login1);

	// Sleep for 2 secs to have a difference between first and second login
	Thread.sleep(2000);

	ugi.reloginFromKeytab();
	final long secondLogin = user.getLastLogin();
	final LoginContext login2 = user.getLogin();
	Assert.assertTrue("User should have been able to relogin from keytab",
	secondLogin > firstLogin);
	Assert.assertNotNull(login2);
	Assert.assertNotSame(login1, login2);
	}

	@Test
	public void testGetUGIFromKnownSubject() throws Exception {
	KerberosPrincipal principal = new KerberosPrincipal("user");
	File keytab = new File(workDir, "user.keytab");
	kdc.createPrincipal(keytab, principal.getName());

	UserGroupInformation ugi1 =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal.getName(), keytab.getPath());
	Subject subject = ugi1.getSubject();
	User user = getUser(subject);
	Assert.assertNotNull(user);
	LoginContext login = user.getLogin();
	Assert.assertNotNull(login);

	// User instance and/or login context should not change.
	UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
	Assert.assertSame(user, getUser(ugi2.getSubject()));
	Assert.assertSame(login, user.getLogin());
	}

	@Test
	public void testGetUGIFromExternalSubject() throws Exception {
	KerberosPrincipal principal = new KerberosPrincipal("user");
	File keytab = new File(workDir, "user.keytab");
	kdc.createPrincipal(keytab, principal.getName());

	UserGroupInformation ugi =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal.getName(), keytab.getPath());
	Subject subject = ugi.getSubject();
	removeUser(subject);

	// first call to get the ugi should add the User instance w/o a login
	// context.
	UserGroupInformation ugi1 = UserGroupInformation.getUGIFromSubject(subject);
	Assert.assertSame(subject, ugi1.getSubject());
	User user = getUser(subject);
	Assert.assertNotNull(user);
	Assert.assertEquals(principal.getName(), user.getName());
	Assert.assertNull(user.getLogin());

	// subsequent call should not change the existing User instance.
	UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
	Assert.assertSame(subject, ugi2.getSubject());
	Assert.assertSame(user, getUser(ugi2.getSubject()));
	Assert.assertNull(user.getLogin());
	}

	@Test
	public void testGetUGIFromExternalSubjectWithLogin() throws Exception {
	KerberosPrincipal principal = new KerberosPrincipal("user");
	File keytab = new File(workDir, "user.keytab");
	kdc.createPrincipal(keytab, principal.getName());

	// alter the User's login context to appear to be a foreign and
	// unmanagable context.
	UserGroupInformation ugi =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal.getName(), keytab.getPath());
	Subject subject = ugi.getSubject();
	User user = getUser(subject);
	final LoginContext dummyLogin = Mockito.mock(LoginContext.class);
	user.setLogin(dummyLogin);

	// nothing should change.
	UserGroupInformation ugi2 = UserGroupInformation.getUGIFromSubject(subject);
	Assert.assertSame(subject, ugi2.getSubject());
	Assert.assertSame(user, getUser(ugi2.getSubject()));
	Assert.assertSame(dummyLogin, user.getLogin());
	}

	@Test
	public void testUGIRefreshFromKeytab() throws Exception {
	final Configuration conf = new Configuration();
	conf.setBoolean(HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED, true);
	SecurityUtil.setAuthenticationMethod(
	UserGroupInformation.AuthenticationMethod.KERBEROS, conf);
	UserGroupInformation.setConfiguration(conf);

	String principal = "bar";
	File keytab = new File(workDir, "bar.keytab");
	kdc.createPrincipal(keytab, principal);

	UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());

	UserGroupInformation ugi = UserGroupInformation.getLoginUser();

	Assert.assertEquals(UserGroupInformation.AuthenticationMethod.KERBEROS,
	ugi.getAuthenticationMethod());
	Assert.assertTrue(ugi.isFromKeytab());
	Assert.assertTrue(
	UserGroupInformation.isKerberosKeyTabLoginRenewalEnabled());
	Assert.assertTrue(
	UserGroupInformation.getKerberosLoginRenewalExecutor()
	.isPresent());
	}

	@Test
	public void testUGIRefreshFromKeytabDisabled() throws Exception {
	GenericTestUtils.setLogLevel(UserGroupInformation.LOG, Level.DEBUG);
	final Configuration conf = new Configuration();
	conf.setLong(HADOOP_KERBEROS_MIN_SECONDS_BEFORE_RELOGIN, 1);
	conf.setBoolean(HADOOP_KERBEROS_KEYTAB_LOGIN_AUTORENEWAL_ENABLED, false);
	SecurityUtil.setAuthenticationMethod(
	UserGroupInformation.AuthenticationMethod.KERBEROS, conf);
	UserGroupInformation.setConfiguration(conf);

	String principal = "bar";
	File keytab = new File(workDir, "bar.keytab");
	kdc.createPrincipal(keytab, principal);

	UserGroupInformation.loginUserFromKeytab(principal, keytab.getPath());

	UserGroupInformation ugi = UserGroupInformation.getLoginUser();
	Assert.assertEquals(UserGroupInformation.AuthenticationMethod.KERBEROS,
	ugi.getAuthenticationMethod());
	Assert.assertTrue(ugi.isFromKeytab());
	Assert.assertFalse(
	UserGroupInformation.isKerberosKeyTabLoginRenewalEnabled());
	Assert.assertFalse(
	UserGroupInformation.getKerberosLoginRenewalExecutor()
	.isPresent());
	}

	private static KerberosTicket getTicket(UserGroupInformation ugi) {
	Set<KerberosTicket> tickets =
	ugi.getSubject().getPrivateCredentials(KerberosTicket.class);
	return tickets.isEmpty() ? null : tickets.iterator().next();
	}

	// verify ugi has expected principal, a keytab, and has a ticket for
	// the expected principal.
	private static KerberosTicket checkTicketAndKeytab(UserGroupInformation ugi,
	KerberosPrincipal principal, boolean expectIsKeytab) {
	Assert.assertEquals("wrong principal",
	principal.getName(), ugi.getUserName());
	Assert.assertEquals("is not keytab",
	expectIsKeytab, ugi.isFromKeytab());
	KerberosTicket ticket = getTicket(ugi);
	Assert.assertNotNull("no ticket", ticket);
	Assert.assertEquals("wrong principal", principal, ticket.getClient());
	return ticket;
	}

	@Test
	public void testReloginForUGIFromSubject() throws Exception {
	KerberosPrincipal principal1 = new KerberosPrincipal("user1");
	File keytab1 = new File(workDir, "user1.keytab");
	kdc.createPrincipal(keytab1, principal1.getName());

	KerberosPrincipal principal2 = new KerberosPrincipal("user2");
	File keytab2 = new File(workDir, "user2.keytab");
	kdc.createPrincipal(keytab2, principal2.getName());

	// Login a user and remove the User instance so it looks like an
	// "external" subject.
	final Subject extSubject =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal2.getName(), keytab2.getPath()).getSubject();
	removeUser(extSubject);

	// Login another user.
	UserGroupInformation.loginUserFromKeytab(
	principal1.getName(), keytab1.getPath());
	final UserGroupInformation loginUser = UserGroupInformation.getLoginUser();

	loginUser.doAs(new PrivilegedExceptionAction<Void>() {
	@Override
	public Void run() throws IOException {
	KerberosTicket loginTicket =
	checkTicketAndKeytab(loginUser, principal1, true);

	// get the ugi for the previously logged in subject.
	UserGroupInformation extSubjectUser =
	UserGroupInformation.getUGIFromSubject(extSubject);
	KerberosTicket ticket =
	checkTicketAndKeytab(extSubjectUser, principal2, false);

	// verify login user got a new ticket.
	loginUser.reloginFromKeytab();
	KerberosTicket newLoginTicket =
	checkTicketAndKeytab(loginUser, principal1, true);
	Assert.assertNotEquals(loginTicket.getAuthTime(),
	newLoginTicket.getAuthTime());

	// verify an "external" subject ticket does not change.
	extSubjectUser.reloginFromKeytab();
	Assert.assertSame(ticket,
	checkTicketAndKeytab(extSubjectUser, principal2, false));

	// verify subject ugi relogin did not affect the login user.
	Assert.assertSame(newLoginTicket,
	checkTicketAndKeytab(loginUser, principal1, true));

	return null;
	}
	});
	}

	@Test
	public void testReloginForLoginFromSubject() throws Exception {
	KerberosPrincipal principal1 = new KerberosPrincipal("user1");
	File keytab1 = new File(workDir, "user1.keytab");
	kdc.createPrincipal(keytab1, principal1.getName());

	KerberosPrincipal principal2 = new KerberosPrincipal("user2");
	File keytab2 = new File(workDir, "user2.keytab");
	kdc.createPrincipal(keytab2, principal2.getName());

	// login principal1 with a keytab.
	UserGroupInformation.loginUserFromKeytab(
	principal1.getName(), keytab1.getPath());
	final UserGroupInformation originalLoginUser =
	UserGroupInformation.getLoginUser();
	Assert.assertNotNull(getUser(originalLoginUser.getSubject()).getLogin());

	originalLoginUser.doAs(new PrivilegedExceptionAction<Void>() {
	@Override
	public Void run() throws IOException {
	KerberosTicket originalLoginUserTicket =
	checkTicketAndKeytab(originalLoginUser, principal1, true);

	// login principal2 from a subject with keytab. it's external so
	// no login context should be attached to the user.
	final Subject subject =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal2.getName(), keytab2.getPath()).getSubject();
	removeUser(subject);

	// verify the new login user is external.
	UserGroupInformation.loginUserFromSubject(subject);
	Assert.assertNull(getUser(subject).getLogin());
	UserGroupInformation extLoginUser =
	UserGroupInformation.getLoginUser();
	KerberosTicket extLoginUserTicket =
	checkTicketAndKeytab(extLoginUser, principal2, false);

	// verify subject-based login user does not get a new ticket, and
	// original login user not affected.
	extLoginUser.reloginFromKeytab();
	Assert.assertSame(extLoginUserTicket,
	checkTicketAndKeytab(extLoginUser, principal2, false));
	Assert.assertSame(originalLoginUserTicket,
	checkTicketAndKeytab(originalLoginUser, principal1, true));

	// verify original login user gets a new ticket, new login user
	// not affected.
	originalLoginUser.reloginFromKeytab();
	Assert.assertNotSame(originalLoginUserTicket,
	checkTicketAndKeytab(originalLoginUser, principal1, true));
	Assert.assertSame(extLoginUserTicket,
	checkTicketAndKeytab(extLoginUser, principal2, false));
	return null;
	}
	});
	}

	@Test
	public void testReloginAfterFailedRelogin() throws Exception {
	KerberosPrincipal principal = new KerberosPrincipal("user1");
	File keytab = new File(workDir, "user1.keytab");
	File keytabBackup = new File(keytab + ".backup");
	kdc.createPrincipal(keytab, principal.getName());

	UserGroupInformation.loginUserFromKeytab(
	principal.getName(), keytab.getPath());
	final UserGroupInformation loginUser = UserGroupInformation.getLoginUser();
	checkTicketAndKeytab(loginUser, principal, true);

	// move the keytab to induce a relogin failure.
	Assert.assertTrue(keytab.renameTo(keytabBackup));
	try {
	loginUser.reloginFromKeytab();
	Assert.fail("relogin should fail");
	} catch (KerberosAuthException kae) {
	// expected.
	}

	// even though no KeyTab object, ugi should know it's keytab based.
	Assert.assertTrue(loginUser.isFromKeytab());
	Assert.assertNull(getTicket(loginUser));

	// move keytab back to enable relogin to succeed.
	Assert.assertTrue(keytabBackup.renameTo(keytab));
	loginUser.reloginFromKeytab();
	checkTicketAndKeytab(loginUser, principal, true);
	}

	// verify getting concurrent relogins blocks to avoid indeterminate
	// credentials corruption, but getting a ugi for the subject does not block.
	@Test(timeout=180000)
	public void testConcurrentRelogin() throws Exception {
	final CyclicBarrier barrier = new CyclicBarrier(2);
	final CountDownLatch latch = new CountDownLatch(1);
	assertTrue(UserGroupInformation.isSecurityEnabled());

	KerberosPrincipal principal = new KerberosPrincipal("testUser");
	File keytab = new File(workDir, "user1.keytab");
	kdc.createPrincipal(keytab, principal.getName());

	// create a keytab ugi.
	final UserGroupInformation loginUgi =
	UserGroupInformation.loginUserFromKeytabAndReturnUGI(
	principal.getName(), keytab.getPath());
	assertEquals(AuthenticationMethod.KERBEROS,
	loginUgi.getAuthenticationMethod());
	assertTrue(loginUgi.isFromKeytab());

	// create a new ugi instance based on subject from the logged in user.
	final UserGroupInformation clonedUgi =
	UserGroupInformation.getUGIFromSubject(loginUgi.getSubject());
	assertEquals(AuthenticationMethod.KERBEROS,
	clonedUgi.getAuthenticationMethod());
	assertTrue(clonedUgi.isFromKeytab());

	// cause first relogin to block on a barrier in logout to verify relogins
	// are atomic.
	User user = getUser(loginUgi.getSubject());
	final LoginContext spyLogin = Mockito.spy(user.getLogin());
	user.setLogin(spyLogin);
	Mockito.doAnswer(new Answer<Void>(){
	@Override
	public Void answer(InvocationOnMock invocation)
	throws Throwable {
	invocation.callRealMethod();
	latch.countDown();
	barrier.await();
	return null;
	}
	}).when(spyLogin).logout();

	Future<Void> relogin = executor.submit(
	new Callable<Void>(){
	@Override
	public Void call() throws Exception {
	Thread.currentThread().setName("relogin");
	loginUgi.reloginFromKeytab();
	return null;
	}
	});
	// wait for the thread to block on the barrier in the logout of the
	// relogin.
	assertTrue("first relogin didn't block",
	latch.await(2, TimeUnit.SECONDS));

	// although the logout removed the keytab instance, verify the ugi
	// knows from its login params that it is supposed to be from a keytab.
	assertTrue(clonedUgi.isFromKeytab());

	// another concurrent re-login should block.
	Mockito.doNothing().when(spyLogin).logout();
	Mockito.doNothing().when(spyLogin).login();
	Future<UserGroupInformation> clonedRelogin = executor.submit(
	new Callable<UserGroupInformation>(){
	@Override
	public UserGroupInformation call() throws Exception {
	Thread.currentThread().setName("clonedRelogin");
	clonedUgi.reloginFromKeytab();
	return clonedUgi;
	}
	});

	try {
	clonedRelogin.get(2, TimeUnit.SECONDS);
	fail("second relogin didn't block!");
	} catch (TimeoutException te) {
	// expected
	}

	// concurrent UGI instantiation should not block and again should
	// know it's supposed to be from a keytab.
	loginUgi.doAs(new PrivilegedExceptionAction<Void>(){
	@Override
	public Void run() throws Exception {
	UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
	assertEquals(principal.getName(), ugi.getUserName());
	assertTrue(ugi.isFromKeytab());
	return null;
	}
	});
	clonedUgi.doAs(new PrivilegedExceptionAction<Void>(){
	@Override
	public Void run() throws Exception {
	UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
	assertEquals(principal.getName(), ugi.getUserName());
	assertTrue(ugi.isFromKeytab());
	return null;
	}
	});

	// second relogin should still be blocked until the original relogin
	// is blocked.
	assertFalse(clonedRelogin.isDone());
	barrier.await();
	relogin.get();
	clonedRelogin.get();
	}

	private User getUser(Subject subject) {
	Iterator<User> iter = subject.getPrincipals(User.class).iterator();
	return iter.hasNext() ? iter.next() : null;
	}

	private void removeUser(Subject subject) {
	// remove User instance so it appears to not be logged in.
	for (Iterator<Principal> iter = subject.getPrincipals().iterator();
	iter.hasNext(); ) {
	if (iter.next() instanceof User) {
	iter.remove();
	}
	}
	}
	}