ZOOKEEPER-4958: Fix client hostname verification ignored in server if ssl.authProvider configured

Reviewers: anmolnar
Author: kezhuw
Closes #2303 from kezhuw/ZOOKEEPER-4958-client-server-hostname-verification

(cherry picked from commit a7fe813)
Signed-off-by: Kezhu Wang <kezhuw@apache.org>

Author: kezhuw

zookeeper-server/src/main/java/org/apache/zookeeper/server/auth/KeyAuthenticationProvider.java

@@ -37,7 +37,7 @@
  * See the "Pluggable ZooKeeper authentication" section of the
  * "Zookeeper Programmer's Guide" for general details of implementing an
  * authentication plugin. e.g.
- * http://zookeeper.apache.org/doc/trunk/zookeeperProgrammers.html#sc_ZooKeeperPluggableAuthentication
+ * http://zookeeper.apache.org/doc/current/zookeeperProgrammers.html#sc_ZooKeeperPluggableAuthentication
  *
  * This class looks for a numeric "key" under the /key node.
  * Authorization is granted if the user passes in as authorization a number

zookeeper-server/src/main/java/org/apache/zookeeper/server/auth/X509AuthenticationProvider.java

@@ -88,6 +88,7 @@ public X509AuthenticationProvider() throws X509Exception {
             boolean crlEnabled = Boolean.parseBoolean(config.getProperty(x509Util.getSslCrlEnabledProperty()));
             boolean ocspEnabled = Boolean.parseBoolean(config.getProperty(x509Util.getSslOcspEnabledProperty()));
             boolean hostnameVerificationEnabled = Boolean.parseBoolean(config.getProperty(x509Util.getSslHostnameVerificationEnabledProperty()));
+            boolean clientHostnameVerificationEnabled = x509Util.isClientHostnameVerificationEnabled(config);
             boolean allowReverseDnsLookup = Boolean.parseBoolean(config.getProperty(x509Util.getSslAllowReverseDnsLookupProperty()));
 
             X509KeyManager km = null;
@@ -120,7 +121,7 @@ public X509AuthenticationProvider() throws X509Exception {
                         crlEnabled,
                         ocspEnabled,
                         hostnameVerificationEnabled,
-                        false,
+                        clientHostnameVerificationEnabled,
                         allowReverseDnsLookup,
                         fipsMode);
                 } catch (TrustManagerException e) {