Add compliant and noncompliant examples of java/unrestricted-file-upload@v1.0

Author: karmakri

src/java/detectors/unrestricted_file_upload/UnrestrictedFileUpload.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package detectors.unrestricted_file_upload;
+
+import javax.servlet.http.HttpServletRequest;
+import java.io.InputStream;
+import java.io.File;
+import java.util.HashMap;
+import org.springframework.util.StringUtils;
+import javax.servlet.ServletException;
+
+public class UnrestrictedFileUpload {
+
+    // {fact rule=unrestricted-file-upload@v1.0 defects=1}
+    public void unrestrictedFileUploadNoncompliant(HttpServletRequest request) {
+        Part filePart = request.getPart("fileToUpload");
+        InputStream fileInputStream = filePart.getInputStream();
+        // Noncompliant: the uploaded file can have any extension.
+        File fileToSave = new File("WebContent/uploaded-files/" + filePart.getSubmittedFileName());
+        Files.copy(fileInputStream, fileToSave.toPath(), StandardCopyOption.REPLACE_EXISTING);
+        response.getOutputStream().println("<p>File was uploaded.</p>");
+    }
+    // {/fact}
+
+    // {fact rule=unrestricted-file-upload@v1.0 defects=0}
+    public void unrestrictedFileUploadCompliant(HttpServletRequest request, HttpServletResponse response) {
+        Part filePart = request.getPart("fileToUpload");
+        // Compliant: the uploaded file must have one of the allowed extensions.
+        if (filePart.getSubmittedFileName().endsWith(".jpg") || filePart.getSubmittedFileName().endsWith(".png")) {
+            InputStream fileInputStream = filePart.getInputStream();
+            File fileToSave = new File("WebContent/uploaded-files/" + filePart.getSubmittedFileName());
+            Files.copy(fileInputStream, fileToSave.toPath(), StandardCopyOption.REPLACE_EXISTING);
+            response.getOutputStream().println("<p>File was uploaded.</p>");
+        }
+        else {
+            response.getOutputStream().println("<p>File was not uploaded.</p>");
+        }
+    }
+    // {/fact}
+
+}