vuln-fix: Temporary File Information Disclosure

This fixes temporary file information disclosure vulnerability due to the use
of the vulnerable `File.createTempFile()` method. The vulnerability is fixed by
using the `Files.createTempFile()` method which sets the correct posix permissions.

Weakness: CWE-377: Insecure Temporary File
Severity: Medium
CVSSS: 5.5
Detection: CodeQL & OpenRewrite (https://public.moderne.io/recipes/org.openrewrite.java.security.SecureTempFileCreation)

Reported-by: Jonathan Leitschuh <Jonathan.Leitschuh@gmail.com>
Signed-off-by: Jonathan Leitschuh <Jonathan.Leitschuh@gmail.com>

Bug-tracker: JLLeitschuh/security-research#18


Co-authored-by: Moderne <team@moderne.io>

src/main/java/org/apache/maven/plugins/checkstyle/CheckstyleViolationCheckMojo.java

@@ -27,6 +27,7 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.Reader;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -855,7 +856,7 @@ else if ( "plain".equals( outputFileFormat ) )
                 {
                     // Write a plain output file to the standard output file,
                     // and write an XML output file to the temp directory that can be used to count violations
-                    outputXmlFile = File.createTempFile( "checkstyle-result", ".xml" );
+                    outputXmlFile = Files.createTempFile( "checkstyle-result", ".xml" ).toFile();
                     outputXmlFile.deleteOnExit();
                     OutputStream xmlOut = getOutputStream( outputXmlFile );
                     CompositeAuditListener compoundListener = new CompositeAuditListener();