From 6186c3b72fb4d898f55e58ff42a5c56286e8fea4 Mon Sep 17 00:00:00 2001
From: Federico Pellegrin <fede@evolware.org>
Date: Mon, 25 Nov 2019 09:07:25 +0100
Subject: [PATCH] Prevent Oops when Whitelisted Commands input is empty

---
 core/src/main/java/jenkins/security/s2m/AdminWhitelistRule.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/src/main/java/jenkins/security/s2m/AdminWhitelistRule.java b/core/src/main/java/jenkins/security/s2m/AdminWhitelistRule.java
index 347857b32f..36d7f1881e 100644
--- a/core/src/main/java/jenkins/security/s2m/AdminWhitelistRule.java
+++ b/core/src/main/java/jenkins/security/s2m/AdminWhitelistRule.java
@@ -162,7 +162,7 @@ public class AdminWhitelistRule implements StaplerProxy {
     @RequirePOST
     public HttpResponse doSubmit(StaplerRequest req) throws IOException {
         StringBuilder whitelist = new StringBuilder(Util.fixNull(req.getParameter("whitelist")));
-        if (whitelist.charAt(whitelist.length() - 1) != '\n')
+        if ((whitelist.length() > 0) && (whitelist.charAt(whitelist.length() - 1) != '\n'))
             whitelist.append("\n");
 
         Enumeration e = req.getParameterNames();