RANGER-5333:Configurable Master key name for Ranger KMS DB with Luna HSM (#680)

* RANGER-5333:Configurable Master key for Luna HSM

# Conflicts:
#	kms/src/main/java/org/apache/hadoop/crypto/key/RangerHSM.java

* RANGER-5333:Added default MK alias value to dbks-site.xml

* RANGER-5333: Resolved checkstyle error

Author: ChinmayHegde24

kms/config/kms-webapp/dbks-site.xml

@@ -405,6 +405,12 @@
   	<value>false</value>
   	<description></description>
   </property>
+
+  <property>
+        <name>ranger.ks.hsm.masterkey.alias</name>
+        <value>RangerKMSKey</value>
+        <description>Custom alias for Luna HSM master key</description>
+  </property>
 
   <property>
   	<name>ranger.ks.hsm.partition.name</name>

kms/src/main/java/org/apache/hadoop/crypto/key/RangerHSM.java

@@ -48,11 +48,13 @@ public class RangerHSM implements RangerKMSMKI {
     private static final String PARTITION_NAME          = "ranger.ks.hsm.partition.name";
     private static final String HSM_TYPE                = "ranger.ks.hsm.type";
     private static final String MK_KEY_SIZE             = "ranger.kms.hsm.masterkey.size";
-    private static final String ALIAS                   = "RangerKMSKey";
+    private static final String MK_ALIAS                = "ranger.ks.hsm.masterkey.alias";
+    private static final String DEFAULT_MK_ALIAS        = "RangerKMSKey";
 
     private KeyStore myStore;
     private String   hsmKeystore;
-    private int mkKeySize;
+    private String   mkAlias;
+    private int      mkKeySize;
 
     public RangerHSM() {
     }
@@ -65,6 +67,7 @@ public RangerHSM(Configuration conf) {
          */
         String passwd        = conf.get(PARTITION_PASSWORD);
         String partitionName = conf.get(PARTITION_NAME);
+        this.mkAlias         = conf.get(MK_ALIAS, DEFAULT_MK_ALIAS);
         this.mkKeySize       = conf.getInt(MK_KEY_SIZE, DEFAULT_MK_KEY_SIZE);
         String errorMsg      = StringUtils.EMPTY;
 
@@ -103,7 +106,7 @@ public boolean generateMasterKey(String password) throws Throwable {
 
         boolean isMKGenerated = false;
 
-        if (!this.myStore.containsAlias(ALIAS)) {
+        if (!this.myStore.containsAlias(mkAlias)) {
             try {
                 logger.info("Generating AES Master Key for '{}' HSM Provider and keySize is {}", hsmKeystore, this.mkKeySize);
 
@@ -113,14 +116,14 @@ public boolean generateMasterKey(String password) throws Throwable {
 
                 SecretKey aesKey = keyGen.generateKey();
 
-                myStore.setKeyEntry(ALIAS, aesKey, password.toCharArray(), (java.security.cert.Certificate[]) null);
+                myStore.setKeyEntry(mkAlias, aesKey, password.toCharArray(), (java.security.cert.Certificate[]) null);
 
                 isMKGenerated = true;
             } catch (Exception e) {
                 logger.error("generateMasterKey : Exception during Ranger Master Key Generation - {}", e.getMessage());
             }
         } else {
-            logger.info("Master key with alias - '{}' already exists!", ALIAS);
+            logger.info("Master key with alias - '{}' already exists!", mkAlias);
         }
 
         logger.debug("<== RangerHSM.generateMasterKey()");
@@ -136,12 +139,12 @@ public String getMasterKey(String password) throws Throwable {
             try {
                 logger.debug("Searching for Ranger Master Key in Luna Keystore");
 
-                boolean result = myStore.containsAlias(ALIAS);
+                boolean result = myStore.containsAlias(mkAlias);
 
                 if (result) {
                     logger.debug("Ranger Master Key is present in Keystore");
 
-                    SecretKey key = (SecretKey) myStore.getKey(ALIAS, password.toCharArray());
+                    SecretKey key = (SecretKey) myStore.getKey(mkAlias, password.toCharArray());
 
                     return Base64.encode(key.getEncoded());
                 }
@@ -161,7 +164,7 @@ public boolean setExternalKeyAsMK(String password, byte[] key) {
             try {
                 Key aesKey = new SecretKeySpec(key, MK_CIPHER);
 
-                myStore.setKeyEntry(ALIAS, aesKey, password.toCharArray(), (java.security.cert.Certificate[]) null);
+                myStore.setKeyEntry(mkAlias, aesKey, password.toCharArray(), (java.security.cert.Certificate[]) null);
 
                 return true;
             } catch (KeyStoreException e) {