HADOOP-13519. Make Path Serializable. Contributed by Steve Loughran

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/Path.java

@@ -19,6 +19,9 @@
 package org.apache.hadoop.fs;
 
 import java.io.IOException;
+import java.io.InvalidObjectException;
+import java.io.ObjectInputValidation;
+import java.io.Serializable;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.regex.Pattern;
@@ -37,7 +40,7 @@ import org.apache.hadoop.conf.Configuration;
 @Stringable
 @InterfaceAudience.Public
 @InterfaceStability.Stable
-public class Path implements Comparable {
+public class Path implements Comparable, Serializable, ObjectInputValidation {
 
   /**
    * The directory separator, a slash.
@@ -66,6 +69,8 @@ public class Path implements Comparable {
   private static final Pattern HAS_DRIVE_LETTER_SPECIFIER =
       Pattern.compile("^/?[a-zA-Z]:");
 
+  private static final long serialVersionUID = 0xad00f;
+
   private URI uri; // a hierarchical uri
 
   /**
@@ -565,4 +570,17 @@ public class Path implements Comparable {
     }
     return new Path(newUri);
   }
+
+  /**
+   * Validate the contents of a deserialized Path, so as
+   * to defend against malicious object streams.
+   * @throws InvalidObjectException if there's no URI
+   */
+  @Override
+  public void validateObject() throws InvalidObjectException {
+    if (uri == null) {
+      throw new InvalidObjectException("No URI in deserialized Path");
+    }
+
+  }
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestPath.java

@@ -17,9 +17,14 @@
  */
 
 package org.apache.hadoop.fs;
+import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Arrays;
@@ -506,4 +511,19 @@ public class TestPath {
     assertFalse(Path.isWindowsAbsolutePath("C:test", false));
     assertFalse(Path.isWindowsAbsolutePath("/C:test", true));
   }
+
+  @Test(timeout = 30000)
+  public void testSerDeser() throws Throwable {
+    Path source = new Path("hdfs://localhost:4040/scratch");
+    ByteArrayOutputStream baos = new ByteArrayOutputStream(256);
+    try(ObjectOutputStream oos = new ObjectOutputStream(baos)) {
+      oos.writeObject(source);
+    }
+    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+    try (ObjectInputStream ois = new ObjectInputStream(bais)) {
+      Path deser = (Path) ois.readObject();
+      Assert.assertEquals(source, deser);
+    }
+
+  }
 }