Restrict everything excepting the predefined list of entries.

core/src/main/java/hudson/model/Slave.java

@@ -51,8 +51,10 @@ import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLConnection;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
+import java.util.TreeSet;
 
 import javax.servlet.ServletException;
 
@@ -322,13 +324,14 @@ public abstract class Slave extends Node implements Serializable {
 
         public URL getURL() throws MalformedURLException {
             String name = fileName;
-            if (name.equals("hudson-cli.jar"))  name="jenkins-cli.jar";
             
-            // Prevent the sandbox escaping (SECURITY-195)
-            if (name.equals("..") || name.startsWith("../") || name.startsWith("..\\") || 
-                    name.replace('\\','/').contains("/../")) {
-                throw new MalformedURLException("The specified file path " + fileName + " contains '..'. "
-                        + "The path is not allowed due to security reasons");
+            // Prevent the access to war contents & prevent the folder escaping (SECURITY-195)
+            if (!ALLOWED_JNLPJARS_FILES.contains(name)) {
+                throw new MalformedURLException("The specified file path " + fileName + " is not allowed due to security reasons");
+            }
+            
+            if (name.equals("hudson-cli.jar"))  {
+                name="jenkins-cli.jar";
             }
             
             URL res = Jenkins.getInstance().servletContext.getResource("/WEB-INF/" + name);
@@ -505,4 +508,10 @@ public abstract class Slave extends Node implements Serializable {
      * Determines the workspace root file name for those who really really need the shortest possible path name.
      */
     private static final String WORKSPACE_ROOT = System.getProperty(Slave.class.getName()+".workspaceRoot","workspace");
+
+    /**
+     * Provides a collection of file names, which are accessible via /jnlpJars link.
+     */
+    private static final Set<String> ALLOWED_JNLPJARS_FILES = new TreeSet<String>
+        (Arrays.asList("slave.jar", "remoting.jar", "jenkins-cli.jar", "hudson-cli.jar"));
 }

test/src/test/java/hudson/model/SlaveTest2.java

@@ -52,9 +52,19 @@ public class SlaveTest2 {
         
         // Spot-check correct requests
         assertJnlpJarUrlIsAllowed(slave, "slave.jar");
+        assertJnlpJarUrlIsAllowed(slave, "remoting.jar");
         assertJnlpJarUrlIsAllowed(slave, "jenkins-cli.jar");
+        assertJnlpJarUrlIsAllowed(slave, "hudson-cli.jar");
         
-        // Go to the upper level
+        // Check that requests to other WEB-INF contents fail
+        assertJnlpJarUrlFails(slave, "web.xml");
+        assertJnlpJarUrlFails(slave, "web.xml");
+        assertJnlpJarUrlFails(slave, "classes/bundled-plugins.txt");
+        assertJnlpJarUrlFails(slave, "classes/dependencies.txt");
+        assertJnlpJarUrlFails(slave, "plugins/ant.hpi");
+        assertJnlpJarUrlFails(slave, "nonexistentfolder/something.txt");
+        
+        // Try various kinds of folder escaping (SECURITY-195)
         assertJnlpJarUrlFails(slave, "../");
         assertJnlpJarUrlFails(slave, "..");
         assertJnlpJarUrlFails(slave, "..\\");
@@ -89,7 +99,6 @@ public class SlaveTest2 {
         // Access from a Web client
         JenkinsRule.WebClient client = rule.createWebClient();
         client.getPage(client.getContextPath() + "jnlpJars/" + URLEncoder.encode(url, "UTF-8")).getWebResponse().getContentAsString();
-        client.getPage(jnlpJar.getURL()).getWebResponse().getContentAsString();
-        
+        client.getPage(jnlpJar.getURL()).getWebResponse().getContentAsString();  
     }
 }