XWiki Platform's configuration files can be accessed through the webjars API

@@ -0,0 +1,54 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.flamingo.test.docker;
+
+import java.net.URI;
+
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.Test;
+import org.xwiki.test.docker.junit5.UITest;
+import org.xwiki.test.ui.TestUtils;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+/**
+ * Tests related to the webjars endpoint.
+ *
+ * @version $Id$
+ */
+@UITest
+class WebJarsIT
+{
+    @Test
+    @Order(1)
+    void pathTraversal(TestUtils setup) throws Exception
+    {
+        URI uri = new URI(StringUtils.removeEnd(setup.rest().getBaseURL(), "rest")
+            + "webjars/wiki%3Axwiki/..%2F..%2F..%2F..%2F..%2FWEB-INF%2Fxwiki.cfg");
+
+        GetMethod response = setup.rest().executeGet(uri);
+
+        assertNotEquals(200, response.getStatusCode());
+
+        response.releaseConnection();
+    }
+}

@@ -59,6 +59,7 @@
 import org.xwiki.cache.CacheException;
 import org.xwiki.cache.CacheManager;
 import org.xwiki.cache.config.LRUCacheConfiguration;
+import org.xwiki.classloader.internal.ClassLoaderUtils;
 import org.xwiki.component.annotation.Component;
 import org.xwiki.component.manager.ComponentLifecycleException;
 import org.xwiki.component.manager.ComponentLookupException;
@@ -1107,19 +1108,15 @@ private Template getClassloaderTemplate(String prefixPath, String templateName)
 
     private Template getClassloaderTemplate(ClassLoader classloader, String prefixPath, String templateName)
     {
-        String templatePath = prefixPath + templateName;
-
-        // Prevent access to resources from other directories
-        Path normalizedResource = Paths.get(templatePath).normalize();
-        // Protect against directory attacks.
-        if (!normalizedResource.startsWith(prefixPath)) {
-            this.logger.warn("Direct access to skin file [{}] refused. Possible break-in attempt!", normalizedResource);
+        URL url;
+        try {
+            url = ClassLoaderUtils.getResource(classloader, prefixPath, templateName);
+        } catch (IllegalArgumentException e) {
+            this.logger.warn("The template name [{}] is trying to execute a path traversal attack!", templateName);
 
             return null;
         }
 
-        URL url = classloader.getResource(templatePath);
-
         return url != null ? new ClassloaderTemplate(new ClassloaderResource(url, templateName)) : null;
     }
 

@@ -92,7 +92,7 @@ public void handle(ResourceReference resourceReference, ResourceReferenceHandler
                     sendError(HttpStatus.SC_NOT_FOUND, "Resource not found [%s].",
                         getResourceName(typedResourceReference));
                 }
-            } catch (IOException | ResourceReferenceHandlerException e) {
+            } catch (Exception e) {
                 this.logger.error(e.getMessage(), e);
                 sendError(HttpStatus.SC_INTERNAL_SERVER_ERROR, e.getMessage());
             }

@@ -24,6 +24,7 @@
 import java.nio.charset.StandardCharsets;
 
 import org.apache.commons.io.IOUtils;
+import org.xwiki.classloader.internal.ClassLoaderUtils;
 
 /**
  * JAR resource source for Skin Extensions.
@@ -58,7 +59,7 @@ public String getContent()
         try {
             // Load from the current context class loader to allow extensions to contribute skin extensions.
             ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
-            try (InputStream in = contextClassLoader.getResourceAsStream(this.resourceName)) {
+            try (InputStream in = ClassLoaderUtils.getResourceAsStream(contextClassLoader, this.resourceName)) {
                 return IOUtils.toString(in, StandardCharsets.UTF_8);
             }
         } catch (NullPointerException e) {

@@ -0,0 +1,50 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+ */
+package org.xwiki.skin.test.ui;
+
+import java.net.URI;
+
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.junit.jupiter.api.Test;
+import org.xwiki.test.docker.junit5.UITest;
+import org.xwiki.test.ui.TestUtils;
+
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+/**
+ * Verify the behavior of resource based skin resources.
+ *
+ * @version $Id$
+ */
+@UITest
+class SXSkinIT
+{
+    @Test
+    void pathTraversal(TestUtils setup) throws Exception
+    {
+        URI uri = new URI(setup.getURL("Main", "WebHome", "sx", "resource=../../WEB-INF/xwiki.cfg"));
+
+        GetMethod response = setup.rest().executeGet(uri);
+
+        assertNotEquals(200, response.getStatusCode());
+
+        response.releaseConnection();
+     }
+}

@@ -30,6 +30,7 @@
 
 import org.apache.tika.mime.MediaType;
 import org.xwiki.classloader.ClassLoaderManager;
+import org.xwiki.classloader.internal.ClassLoaderUtils;
 import org.xwiki.component.annotation.Component;
 import org.xwiki.resource.ResourceReferenceHandlerException;
 import org.xwiki.resource.ResourceType;
@@ -76,8 +77,8 @@ public List<ResourceType> getSupportedResourceReferences()
     @Override
     protected InputStream getResourceStream(WebJarsResourceReference resourceReference)
     {
-        String resourcePath = String.format("%s%s", WEBJARS_RESOURCE_PREFIX, getResourceName(resourceReference));
-        return getClassLoader(resourceReference.getNamespace()).getResourceAsStream(resourcePath);
+        return ClassLoaderUtils.getResourceAsStream(getClassLoader(resourceReference.getNamespace()),
+            WEBJARS_RESOURCE_PREFIX, getResourceName(resourceReference));
     }
 
     @Override

@@ -19,6 +19,10 @@
  */
 package org.xwiki.webjars.test.ui;
 
+import java.net.URI;
+
+import org.apache.commons.httpclient.methods.GetMethod;
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Rule;
 import org.junit.Test;
 import org.openqa.selenium.By;
@@ -27,7 +31,8 @@
 import org.xwiki.test.ui.SuperAdminAuthenticationRule;
 import org.xwiki.test.ui.po.ViewPage;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertNotEquals;
 
 /**
  * Functional tests for the WebJars integration.
@@ -73,4 +78,17 @@ public void testWebJars() throws Exception
         // Verify that the served resource is the one from the webjars
         assertTrue(getDriver().getPageSource().contains("// AjaxQ jQuery Plugin"));
     }
+
+    @Test
+    public void pathTraversal() throws Exception
+    {
+        URI uri = new URI(StringUtils.removeEnd(getUtil().rest().getBaseURL(), "rest")
+            + "webjars/wiki%3Axwiki/..%2F..%2F..%2F..%2F..%2FWEB-INF%2Fxwiki.cfg");
+
+        GetMethod response = getUtil().rest().executeGet(uri);
+
+        assertNotEquals(200, response.getStatusCode());
+
+        response.releaseConnection();
+    }
 }