HADOOP-18504. Fixed an unhandled NullPointerException in class KeyProvider (#5064)

Contributed by FuzzingTeam

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

@@ -639,13 +639,14 @@ public abstract class KeyProvider implements Closeable {
   public abstract void flush() throws IOException;
 
   /**
-   * Split the versionName in to a base name. Converts "/aaa/bbb/3" to
+   * Split the versionName in to a base name. Converts "/aaa/bbb@3" to
    * "/aaa/bbb".
    * @param versionName the version name to split
    * @return the base name of the key
    * @throws IOException raised on errors performing I/O.
    */
   public static String getBaseName(String versionName) throws IOException {
+    Objects.requireNonNull(versionName, "VersionName cannot be null");
     int div = versionName.lastIndexOf('@');
     if (div == -1) {
       throw new IOException("No version in key path " + versionName);

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

@@ -36,6 +36,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import static org.apache.hadoop.test.LambdaTestUtils.intercept;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
@@ -62,6 +63,8 @@ public class TestKeyProvider {
     } catch (IOException e) {
       assertTrue(true);
     }
+    intercept(NullPointerException.class, () ->
+        KeyProvider.getBaseName(null));
   }
 
   @Test