HADOOP-13461. NPE in KeyProvider.rollNewVersion. Contributed by Colm O hEigeartaigh.

(cherry picked from commit e83be44af530d57d9c49cd989d030052548a068b)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProvider.java

@@ -557,6 +557,10 @@ public abstract class KeyProvider {
   public KeyVersion rollNewVersion(String name) throws NoSuchAlgorithmException,
                                                        IOException {
     Metadata meta = getMetadata(name);
+    if (meta == null) {
+      throw new IOException("Can't find Metadata for key " + name);
+    }
+
     byte[] material = generateKey(meta.getBitLength(), meta.getCipher());
     return rollNewVersion(name, material);
   }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/crypto/key/TestKeyProvider.java

@@ -22,6 +22,7 @@ import org.apache.hadoop.conf.Configuration;
 
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.security.ProviderUtils;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.Test;
 
 import java.io.IOException;
@@ -38,6 +39,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.fail;
 
 public class TestKeyProvider {
 
@@ -182,7 +184,10 @@ public class TestKeyProvider {
 
     @Override
     public Metadata getMetadata(String name) throws IOException {
-      return new Metadata(CIPHER, 128, "description", null, new Date(), 0);
+      if (!"unknown".equals(name)) {
+        return new Metadata(CIPHER, 128, "description", null, new Date(), 0);
+      }
+      return null;
     }
 
     @Override
@@ -236,6 +241,27 @@ public class TestKeyProvider {
     Assert.assertNotNull(kp.material);
   }
 
+  @Test
+  public void testRolloverUnknownKey() throws Exception {
+    MyKeyProvider kp = new MyKeyProvider(new Configuration());
+    KeyProvider.Options options = new KeyProvider.Options(new Configuration());
+    options.setCipher(CIPHER);
+    options.setBitLength(128);
+    kp.createKey("hello", options);
+    Assert.assertEquals(128, kp.size);
+    Assert.assertEquals(CIPHER, kp.algorithm);
+    Assert.assertNotNull(kp.material);
+
+    kp = new MyKeyProvider(new Configuration());
+    try {
+      kp.rollNewVersion("unknown");
+      fail("should have thrown");
+    } catch (IOException e) {
+      String expectedError = "Can't find Metadata for key";
+      GenericTestUtils.assertExceptionContains(expectedError, e);
+    }
+  }
+
   @Test
   public void testConfiguration() throws Exception {
     Configuration conf = new Configuration(false);