[SPARK-24506][UI] Add UI filters to tabs added after binding

## What changes were proposed in this pull request?

Currently, `spark.ui.filters` are not applied to the handlers added after binding the server. This means that every page which is added after starting the UI will not have the filters configured on it. This can allow unauthorized access to the pages.

The PR adds the filters also to the handlers added after the UI starts.

## How was this patch tested?

manual tests (without the patch, starting the thriftserver with `--conf spark.ui.filters=org.apache.hadoop.security.authentication.server.AuthenticationFilter --conf spark.org.apache.hadoop.security.authentication.server.AuthenticationFilter.params="type=simple"` you can access `http://localhost:4040/sqlserver`; with the patch, 401 is the response as for the other pages).

Author: Marco Gaido <[email protected]>

Closes #21523 from mgaido91/SPARK-24506.

(cherry picked from commit f53818d)
Signed-off-by: Marcelo Vanzin <[email protected]>

Author: mgaido91

core/src/main/scala/org/apache/spark/deploy/history/HistoryServer.scala

@@ -152,7 +152,6 @@ class HistoryServer(
     assert(serverInfo.isDefined, "HistoryServer must be bound before attaching SparkUIs")
     handlers.synchronized {
       ui.getHandlers.foreach(attachHandler)
-      addFilters(ui.getHandlers, conf)
     }
   }
 

core/src/main/scala/org/apache/spark/ui/JettyUtils.scala

@@ -263,7 +263,7 @@ private[spark] object JettyUtils extends Logging {
     filters.foreach {
       case filter : String =>
         if (!filter.isEmpty) {
-          logInfo("Adding filter: " + filter)
+          logInfo(s"Adding filter $filter to ${handlers.map(_.getContextPath).mkString(", ")}.")
           val holder : FilterHolder = new FilterHolder()
           holder.setClassName(filter)
           // Get any parameters for each filter
@@ -406,7 +406,7 @@ private[spark] object JettyUtils extends Logging {
       }
 
       pool.setMaxThreads(math.max(pool.getMaxThreads, minThreads))
-      ServerInfo(server, httpPort, securePort, collection)
+      ServerInfo(server, httpPort, securePort, conf, collection)
     } catch {
       case e: Exception =>
         server.stop()
@@ -506,10 +506,12 @@ private[spark] case class ServerInfo(
     server: Server,
     boundPort: Int,
     securePort: Option[Int],
+    conf: SparkConf,
     private val rootHandler: ContextHandlerCollection) {
 
-  def addHandler(handler: ContextHandler): Unit = {
+  def addHandler(handler: ServletContextHandler): Unit = {
     handler.setVirtualHosts(JettyUtils.toVirtualHosts(JettyUtils.SPARK_CONNECTOR_NAME))
+    JettyUtils.addFilters(Seq(handler), conf)
     rootHandler.addHandler(handler)
     if (!handler.isStarted()) {
       handler.start()