SOLR-14014 Allow disabling AdminUI at launch (#1471)

solr/CHANGES.txt

@@ -67,6 +67,10 @@ Other Changes
 * SOLR-14412: Automatically set urlScheme to https when running secure solr with embedded zookeeper. (Mike Drob)
   Do not erroneously set solr.jetty.https.port system property when running in http mode (Upendra Penegalapati)
 
+* SOLR-14014: Introducing a system property that allows users to disable the Admin UI, which is enabled by default.
+  If you have security concerns or other reasons to disable the Admin UI, you can modify `SOLR_ADMIN_UI_DISABLED`
+  `solr.in.sh`/`solr.in.cmd` at start. (marcussorealheis)
+
 ==================  8.6.0 ==================
 
 Consult the LUCENE_CHANGES.txt file for additional, low level, changes in this release.

solr/bin/solr

@@ -2097,6 +2097,14 @@ else
   SECURITY_MANAGER_OPTS=()
 fi
 
+# Enable ADMIN UI by default, and give the option for users to disable it
+if [ "$SOLR_ADMIN_UI_DISABLED" == "true" ]; then
+  SOLR_ADMIN_UI="-DdisableAdminUI=true"
+  echo -e "ADMIN UI Disabled"
+else
+  SOLR_ADMIN_UI="-DdisableAdminUI=false"
+fi
+
 JAVA_MEM_OPTS=()
 if [ -z "$SOLR_HEAP" ] && [ -n "$SOLR_JAVA_MEM" ]; then
   JAVA_MEM_OPTS=($SOLR_JAVA_MEM)
@@ -2208,7 +2216,7 @@ function start_solr() {
     # users who don't care about useful error msgs can override in SOLR_OPTS with +OmitStackTraceInFastThrow
     "${SOLR_HOST_ARG[@]}" "-Duser.timezone=$SOLR_TIMEZONE" "-XX:-OmitStackTraceInFastThrow" \
     "-Djetty.home=$SOLR_SERVER_DIR" "-Dsolr.solr.home=$SOLR_HOME" "-Dsolr.data.home=$SOLR_DATA_HOME" "-Dsolr.install.dir=$SOLR_TIP" \
-    "-Dsolr.default.confdir=$DEFAULT_CONFDIR" "${LOG4J_CONFIG[@]}" "${SOLR_OPTS[@]}" "${SECURITY_MANAGER_OPTS[@]}")
+    "-Dsolr.default.confdir=$DEFAULT_CONFDIR" "${LOG4J_CONFIG[@]}" "${SOLR_OPTS[@]}" "${SECURITY_MANAGER_OPTS[@]}" "${SOLR_ADMIN_UI}")
 
   if [ "$SOLR_MODE" == "solrcloud" ]; then
     IN_CLOUD_MODE=" in SolrCloud mode"

solr/bin/solr.cmd

@@ -1199,6 +1199,13 @@ IF "%SOLR_SECURITY_MANAGER_ENABLED%"=="true" (
 -Dsolr.internal.network.permission=*
 )
 
+REM Enable ADMIN UI by default, and give the option for users to disable it
+IF "%SOLR_ADMIN_UI_DISABLED%"=="true" (
+  set DISABLE_ADMIN_UI="true"
+) else (
+  set DISABLE_ADMIN_UI="false"
+)
+
 IF NOT "%SOLR_HEAP%"=="" set SOLR_JAVA_MEM=-Xms%SOLR_HEAP% -Xmx%SOLR_HEAP%
 IF "%SOLR_JAVA_MEM%"=="" set SOLR_JAVA_MEM=-Xms512m -Xmx512m
 IF "%SOLR_JAVA_STACK_SIZE%"=="" set SOLR_JAVA_STACK_SIZE=-Xss256k
@@ -1288,6 +1295,7 @@ REM '-OmitStackTraceInFastThrow' ensures stack traces in errors,
 REM users who don't care about useful error msgs can override in SOLR_OPTS with +OmitStackTraceInFastThrow
 set "START_OPTS=%START_OPTS% -XX:-OmitStackTraceInFastThrow"
 set START_OPTS=%START_OPTS% !GC_TUNE! %GC_LOG_OPTS%
+set START_OPTS=%START_OPTS% -DdisableAdminUI=%DISABLE_ADMIN_UI%
 IF NOT "!CLOUD_MODE_OPTS!"=="" set "START_OPTS=%START_OPTS% !CLOUD_MODE_OPTS!"
 IF NOT "!IP_ACL_OPTS!"=="" set "START_OPTS=%START_OPTS% !IP_ACL_OPTS!"
 IF NOT "%REMOTE_JMX_OPTS%"=="" set "START_OPTS=%START_OPTS% %REMOTE_JMX_OPTS%"

solr/bin/solr.in.cmd

@@ -203,3 +203,8 @@ REM Runtime properties are passed to the security policy file (server\etc\securi
 REM You can also tweak via standard JDK files such as ~\.java.policy, see https://s.apache.org/java8policy
 REM This is experimental! It may not work at all with Hadoop/HDFS features.
 REM set SOLR_SECURITY_MANAGER_ENABLED=true
+REM This variable provides you with the option to disable the Admin UI. if you uncomment the variable below and
+REM change the value to true. The option is configured as a system property as defined in SOLR_START_OPTS in the start
+REM scripts.
+REM set SOLR_ADMIN_UI_DISABLED=false
+

solr/bin/solr.in.sh

@@ -234,4 +234,7 @@
 # You can also tweak via standard JDK files such as ~/.java.policy, see https://s.apache.org/java8policy
 # This is experimental! It may not work at all with Hadoop/HDFS features.
 #SOLR_SECURITY_MANAGER_ENABLED=true
-
+# This variable provides you with the option to disable the Admin UI. if you uncomment the variable below and
+# change the value to true. The option is configured as a system property as defined in SOLR_START_OPTS in the start
+# scripts.
+# SOLR_ADMIN_UI_DISABLED=false

solr/core/src/java/org/apache/solr/servlet/LoadAdminUiServlet.java

@@ -15,6 +15,13 @@
  * limitations under the License.
  */
 package org.apache.solr.servlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
 
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.io.output.CloseShieldOutputStream;
@@ -24,15 +31,6 @@ import org.apache.solr.common.params.CommonParams;
 import org.apache.solr.core.CoreContainer;
 import org.apache.solr.core.SolrCore;
 
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStreamWriter;
-import java.io.Writer;
-import java.nio.charset.StandardCharsets;
-
 /**
  * A simple servlet to load the Solr Admin UI
  * 
@@ -40,13 +38,20 @@ import java.nio.charset.StandardCharsets;
  */
 public final class LoadAdminUiServlet extends BaseSolrServlet {
 
+  // check system properties for whether or not admin UI is disabled, default is false
+  private static final boolean disabled = Boolean.parseBoolean(System.getProperty("disableAdminUI", "false"));
+
   @Override
-  public void doGet(HttpServletRequest _request,
-                    HttpServletResponse _response)
-      throws IOException {
+  public void doGet(HttpServletRequest _request, HttpServletResponse _response) throws IOException {
+    if(disabled){
+      _response.sendError(404, "Solr Admin UI is disabled. To enable it, change the default value of SOLR_ADMIN_UI_" +
+          "ENABLED in bin/solr.in.sh or solr.in.cmd.");
+      return;
+    }
     HttpServletRequest request = SolrDispatchFilter.closeShield(_request, false);
     HttpServletResponse response = SolrDispatchFilter.closeShield(_response, false);
 
+
     response.addHeader("X-Frame-Options", "DENY"); // security: SOLR-7966 - avoid clickjacking for admin interface
 
     // This attribute is set by the SolrDispatchFilter