How to restore file permissions?

Question

linux

Linux Mint 17.2 , user - one
via sudo chmod 644 ~/.config/xfce4/panel/* - I change the permissions on files in the folder
and via sudo ls -al ~/.config/xfce4/panel/ - I see the permissions on files
simply through ls -al ~/.config/xfce4/panel/ get the following:
d????????? ? ? ? ? ? .
d????????? ? ? ? ? ? ..
-????????? ? ? ? ? ? datetime-5.rcd
????????? ? ? ? ? ? launcher-10
-????????? ? ? ? ? ? whiskermenu-1.rc
-????????? ? ? ? ? ? xkb-plugin-9.rc
How to restore access to files so that you can read / write from a non-privileged user?