    def test_valid_id_pathsep(self):
        '''
        Path separators in id should make it invalid
        '''
        opts = {'pki_dir': '/tmp/whatever'}
        # We have to test both path separators because os.path.normpath will
        # convert forward slashes to backslashes on Windows.
        for pathsep in ('/', '\\'):
            self.assertFalse(valid_id(opts, pathsep.join(('..', 'foobar'))))
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.