HADOOP-7101. UserGroupInformation.getCurrentUser() fails when called from non-Hadoop JAAS context. Contributed by Todd Lipcon

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1058875 13f79535-47bb-0310-9956-ffa450edef68

Author: toddlipcon

CHANGES.txt

@@ -440,6 +440,9 @@ Release 0.22.0 - Unreleased
 
     HADOOP-7093. Servlets should default to text/plain (todd)
 
+    HADOOP-7101. UserGroupInformation.getCurrentUser() fails when called from
+    non-Hadoop JAAS context. (todd)
+
 Release 0.21.1 - Unreleased
 
   IMPROVEMENTS

src/java/org/apache/hadoop/security/UserGroupInformation.java

@@ -468,7 +468,11 @@ public boolean hasKerberosCredentials() {
   public static UserGroupInformation getCurrentUser() throws IOException {
     AccessControlContext context = AccessController.getContext();
     Subject subject = Subject.getSubject(context);
-    return subject == null ? getLoginUser() : new UserGroupInformation(subject);
+    if (subject == null || subject.getPrincipals(User.class).isEmpty()) {
+      return getLoginUser();
+    } else {
+      return new UserGroupInformation(subject);
+    }
   }
 
   /**

src/test/core/org/apache/hadoop/security/TestUserGroupInformation.java

@@ -16,11 +16,7 @@
  */
 package org.apache.hadoop.security;
 
-import static org.junit.Assert.assertArrayEquals;
-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 static org.junit.Assert.*;
 import org.mockito.Mockito;
 import static org.mockito.Mockito.mock;
 
@@ -32,6 +28,7 @@
 import java.util.Collection;
 import java.util.List;
 
+import javax.security.auth.Subject;
 import javax.security.auth.login.AppConfigurationEntry;
 import javax.security.auth.login.LoginContext;
 
@@ -383,4 +380,22 @@ public void testDelegateJaasConfiguration() throws Exception {
     // for "foobar"
     LoginContext login = new LoginContext("foobar-app");
   }
+
+  /**
+   * Test for the case that UserGroupInformation.getCurrentUser()
+   * is called when the AccessControlContext has a Subject associated
+   * with it, but that Subject was not created by Hadoop (ie it has no
+   * associated User principal)
+   */
+  @Test
+  public void testUGIUnderNonHadoopContext() throws Exception {
+    Subject nonHadoopSubject = new Subject();
+    Subject.doAs(nonHadoopSubject, new PrivilegedExceptionAction<Void>() {
+        public Void run() throws IOException {
+          UserGroupInformation ugi = UserGroupInformation.getCurrentUser();
+          assertNotNull(ugi);
+          return null;
+        }
+      });
+  }
 }