HDFS-3433. GetImageServlet should allow administrative requestors when security is enabled. Contributed by Aaron T. Myers.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1339543 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/http/HttpServer.java

@@ -95,7 +95,7 @@ public class HttpServer implements FilterContainer {
   // The ServletContext attribute where the daemon Configuration
   // gets stored.
   public static final String CONF_CONTEXT_ATTRIBUTE = "hadoop.conf";
-  static final String ADMINS_ACL = "admins.acl";
+  public static final String ADMINS_ACL = "admins.acl";
   public static final String SPNEGO_FILTER = "SpnegoFilter";
 
   public static final String BIND_ADDRESS = "bind.address";
@@ -744,7 +744,7 @@ public class HttpServer implements FilterContainer {
    * 
    * @param servletContext
    * @param request
-   * @param response
+   * @param response used to send the error response if user does not have admin access.
    * @return true if admin-authorized, false otherwise
    * @throws IOException
    */
@@ -766,20 +766,35 @@ public class HttpServer implements FilterContainer {
                          "authorized to access this page.");
       return false;
     }
-    AccessControlList adminsAcl = (AccessControlList) servletContext
-        .getAttribute(ADMINS_ACL);
-    UserGroupInformation remoteUserUGI =
-        UserGroupInformation.createRemoteUser(remoteUser);
-    if (adminsAcl != null) {
-      if (!adminsAcl.isUserAllowed(remoteUserUGI)) {
+    
+    if (servletContext.getAttribute(ADMINS_ACL) != null &&
+        !userHasAdministratorAccess(servletContext, remoteUser)) {
       response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "User "
           + remoteUser + " is unauthorized to access this page.");
       return false;
     }
-    }
+
     return true;
   }
 
+  /**
+   * Get the admin ACLs from the given ServletContext and check if the given
+   * user is in the ACL.
+   * 
+   * @param servletContext the context containing the admin ACL.
+   * @param remoteUser the remote user to check for.
+   * @return true if the user is present in the ACL, false if no ACL is set or
+   *         the user is not present
+   */
+  public static boolean userHasAdministratorAccess(ServletContext servletContext,
+      String remoteUser) {
+    AccessControlList adminsAcl = (AccessControlList) servletContext
+        .getAttribute(ADMINS_ACL);
+    UserGroupInformation remoteUserUGI =
+        UserGroupInformation.createRemoteUser(remoteUser);
+    return adminsAcl != null && adminsAcl.isUserAllowed(remoteUserUGI);
+  }
+
   /**
    * A very simple servlet to serve up a text representation of the current
    * stack traces. It both returns the stacks to the caller and logs them.

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -62,6 +62,8 @@ Release 2.0.1-alpha - UNRELEASED
 
     HDFS-3422. TestStandbyIsHot timeouts too aggressive (todd)
 
+    HDFS-3433. GetImageServlet should allow administrative requestors when security is enabled. (atm)
+
 Release 2.0.0-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/GetImageServlet.java

@@ -44,6 +44,7 @@ import org.apache.hadoop.hdfs.server.common.StorageInfo;
 import org.apache.hadoop.hdfs.server.protocol.RemoteEditLog;
 import org.apache.hadoop.hdfs.util.DataTransferThrottler;
 import org.apache.hadoop.hdfs.util.MD5FileUtils;
+import org.apache.hadoop.http.HttpServer;
 import org.apache.hadoop.io.MD5Hash;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.util.StringUtils;
@@ -85,11 +86,12 @@ public class GetImageServlet extends HttpServlet {
       final Configuration conf = 
         (Configuration)getServletContext().getAttribute(JspHelper.CURRENT_CONF);
       
-      if(UserGroupInformation.isSecurityEnabled() && 
-          !isValidRequestor(request.getUserPrincipal().getName(), conf)) {
+      if (UserGroupInformation.isSecurityEnabled() && 
+          !isValidRequestor(context, request.getUserPrincipal().getName(), conf)) {
         response.sendError(HttpServletResponse.SC_FORBIDDEN, 
-            "Only Namenode and Secondary Namenode may access this servlet");
-        LOG.warn("Received non-NN/SNN request for image or edits from " 
+            "Only Namenode, Secondary Namenode, and administrators may access " +
+            "this servlet");
+        LOG.warn("Received non-NN/SNN/administrator request for image or edits from " 
             + request.getUserPrincipal().getName() + " at " + request.getRemoteHost());
         return;
       }
@@ -209,8 +211,8 @@ public class GetImageServlet extends HttpServlet {
   }
   
   @VisibleForTesting
-  static boolean isValidRequestor(String remoteUser, Configuration conf)
-      throws IOException {
+  static boolean isValidRequestor(ServletContext context, String remoteUser,
+      Configuration conf) throws IOException {
     if(remoteUser == null) { // This really shouldn't happen...
       LOG.warn("Received null remoteUser while authorizing access to getImage servlet");
       return false;
@@ -237,11 +239,17 @@ public class GetImageServlet extends HttpServlet {
 
     for(String v : validRequestors) {
       if(v != null && v.equals(remoteUser)) {
-        if(LOG.isInfoEnabled()) LOG.info("GetImageServlet allowing: " + remoteUser);
+        LOG.info("GetImageServlet allowing checkpointer: " + remoteUser);
         return true;
       }
     }
-    if(LOG.isInfoEnabled()) LOG.info("GetImageServlet rejecting: " + remoteUser);
+    
+    if (HttpServer.userHasAdministratorAccess(context, remoteUser)) {
+      LOG.info("GetImageServlet allowing administrator: " + remoteUser);
+      return true;
+    }
+    
+    LOG.info("GetImageServlet rejecting: " + remoteUser);
     return false;
   }
   

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestGetImageServlet.java

@@ -21,17 +21,26 @@ import static org.junit.Assert.*;
 
 import java.io.IOException;
 
+import javax.servlet.ServletContext;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.http.HttpServer;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.security.authentication.util.KerberosName;
+import org.apache.hadoop.security.authorize.AccessControlList;
 import org.junit.Test;
+import org.mockito.ArgumentMatcher;
+import org.mockito.Mockito;
 
 public class TestGetImageServlet {
   
   @Test
-  public void testIsValidRequestorWithHa() throws IOException {
+  public void testIsValidRequestor() throws IOException {
     Configuration conf = new HdfsConfiguration();
+    KerberosName.setRules("RULE:[1:$1]\nRULE:[2:$1]");
     
     // Set up generic HA configs.
     conf.set(DFSConfigKeys.DFS_FEDERATION_NAMESERVICES, "ns1");
@@ -53,8 +62,33 @@ public class TestGetImageServlet {
     // Initialize this conf object as though we're running on NN1.
     NameNode.initializeGenericKeys(conf, "ns1", "nn1");
     
+    AccessControlList acls = Mockito.mock(AccessControlList.class);
+    Mockito.when(acls.isUserAllowed(Mockito.<UserGroupInformation>any())).thenReturn(false);
+    ServletContext context = Mockito.mock(ServletContext.class);
+    Mockito.when(context.getAttribute(HttpServer.ADMINS_ACL)).thenReturn(acls);
+    
     // Make sure that NN2 is considered a valid fsimage/edits requestor.
-    assertTrue(GetImageServlet.isValidRequestor("hdfs/host2@TEST-REALM.COM",
-        conf));
+    assertTrue(GetImageServlet.isValidRequestor(context,
+        "hdfs/host2@TEST-REALM.COM", conf));
+    
+    // Mark atm as an admin.
+    Mockito.when(acls.isUserAllowed(Mockito.argThat(new ArgumentMatcher<UserGroupInformation>() {
+      @Override
+      public boolean matches(Object argument) {
+        return ((UserGroupInformation) argument).getShortUserName().equals("atm");
+      }
+    }))).thenReturn(true);
+    
+    // Make sure that NN2 is still considered a valid requestor.
+    assertTrue(GetImageServlet.isValidRequestor(context,
+        "hdfs/host2@TEST-REALM.COM", conf));
+    
+    // Make sure an admin is considered a valid requestor.
+    assertTrue(GetImageServlet.isValidRequestor(context,
+        "atm@TEST-REALM.COM", conf));
+    
+    // Make sure other users are *not* considered valid requestors.
+    assertFalse(GetImageServlet.isValidRequestor(context,
+        "todd@TEST-REALM.COM", conf));
   }
 }