HDFS-16901: RBF: Propagates real user's username via the caller context, when a proxy user is being used. (#5346)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/CallerContext.java

@@ -47,6 +47,7 @@ public final class CallerContext {
   // field names
   public static final String CLIENT_IP_STR = "clientIp";
   public static final String CLIENT_PORT_STR = "clientPort";
+  public static final String REAL_USER_STR = "realUser";
 
   /** The caller context.
    *

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcClient.java

@@ -423,7 +423,7 @@ private Object invokeMethod(
           + router.getRouterId());
     }
 
-    addClientIpToCallerContext();
+    addClientInfoToCallerContext(ugi);
 
     Object ret = null;
     if (rpcMonitor != null) {
@@ -541,19 +541,24 @@ private Object invokeMethod(
 
   /**
    * For tracking which is the actual client address.
-   * It adds trace info "clientIp:ip" and "clientPort:port"
+   * It adds trace info "clientIp:ip", "clientPort:port" and "realUser:userName"
    * in the caller context, removing the old values if they were
    * already present.
    */
-  private void addClientIpToCallerContext() {
+  private void addClientInfoToCallerContext(UserGroupInformation ugi) {
     CallerContext ctx = CallerContext.getCurrent();
     String origContext = ctx == null ? null : ctx.getContext();
     byte[] origSignature = ctx == null ? null : ctx.getSignature();
+    String realUser = null;
+    if (ugi.getRealUser() != null) {
+      realUser = ugi.getRealUser().getUserName();
+    }
     CallerContext.Builder builder =
         new CallerContext.Builder("", contextFieldSeparator)
             .append(CallerContext.CLIENT_IP_STR, Server.getRemoteAddress())
             .append(CallerContext.CLIENT_PORT_STR,
                 Integer.toString(Server.getRemotePort()))
+            .append(CallerContext.REAL_USER_STR, realUser)
             .setSignature(origSignature);
     // Append the original caller context
     if (origContext != null) {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterRpc.java

@@ -39,6 +39,7 @@
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.net.URISyntaxException;
+import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
@@ -210,6 +211,14 @@ public static void globalSetUp() throws Exception {
     cluster.setIndependentDNs();
 
     Configuration conf = new Configuration();
+    // Setup proxy users.
+    conf.set("hadoop.proxyuser.testRealUser.groups", "*");
+    conf.set("hadoop.proxyuser.testRealUser.hosts", "*");
+    String loginUser = UserGroupInformation.getLoginUser().getUserName();
+    conf.set(String.format("hadoop.proxyuser.%s.groups", loginUser), "*");
+    conf.set(String.format("hadoop.proxyuser.%s.hosts", loginUser), "*");
+    // Enable IP proxy users.
+    conf.set(DFSConfigKeys.DFS_NAMENODE_IP_PROXY_USERS, "placeholder");
     conf.setInt(DFSConfigKeys.DFS_LIST_LIMIT, 5);
     cluster.addNamenodeOverrides(conf);
     // Start NNs and DNs and wait until ready
@@ -1871,6 +1880,38 @@ public void testMkdirsWithCallerContext() throws IOException {
     assertTrue(verifyFileExists(routerFS, dirPath));
   }
 
+  @Test
+  public void testRealUserPropagationInCallerContext()
+      throws IOException, InterruptedException {
+    GenericTestUtils.LogCapturer auditlog =
+        GenericTestUtils.LogCapturer.captureLogs(FSNamesystem.auditLog);
+
+    // Current callerContext is null
+    assertNull(CallerContext.getCurrent());
+
+    UserGroupInformation loginUser = UserGroupInformation.getLoginUser();
+    UserGroupInformation realUser = UserGroupInformation
+        .createUserForTesting("testRealUser", new String[]{"group"});
+    UserGroupInformation proxyUser = UserGroupInformation
+        .createProxyUser("testProxyUser", realUser);
+    FileSystem proxyFs = proxyUser.doAs(
+        (PrivilegedExceptionAction<FileSystem>) () -> router.getFileSystem());
+    proxyFs.listStatus(new Path("/"));
+
+
+    final String logOutput = auditlog.getOutput();
+    // Login user, which is used as the router's user, is different from the realUser.
+    assertNotEquals(loginUser.getUserName(), realUser.getUserName());
+    // Login user is used in the audit log's ugi field.
+    assertTrue("The login user is the proxyUser in the UGI field",
+         logOutput.contains(String.format("ugi=%s (auth:PROXY) via %s (auth:SIMPLE)",
+             proxyUser.getUserName(),
+             loginUser.getUserName())));
+    // Real user is added to the caller context.
+    assertTrue("The audit log should contain the real user.",
+        logOutput.contains(String.format("realUser:%s", realUser.getUserName())));
+  }
+
   @Test
   public void testSetBalancerBandwidth() throws Exception {
     long defaultBandwidth =