Mysterious inaccessible folder

Posting about this here, in case anyone else stumbles upon it and wonders what is going on.

Forum member caramel reported this:

ls /home/firefox/.cache/doc
ls: impossible d'accéder à '/home/firefox/.cache/doc': Permission denied

See forum post:

https://forum.puppylinux.com/viewtopic.php?t=9423

I stumbled upon why that is happening. Reproducing my reply from the forum:

@Caramel
Like you, I was immensely puzzled.
I see Chromium also creates /home/chromium/.cache/doc, with the same problem.

But then I read this:

https://github.com/flatpak/xdg-desktop-portal/issues/512

The document portal is a fuse mount, so it is denied access to by any uid other than the owning uid, including root. So, I expect the regular /run/user/1000/doc to be inaccessible by root.

So, did this:

# login -f firefox
# whoami
firefox
# ls /home/firefox/.cache/doc
by-app
# 

...works!

An extra note: That path /home/firefox/.cache does not get saved when you choose to save the session. This is because it can get rather big. For anyone interested in how that exclusion is achieved, look at /etc/rc.d/rw-merge, line 122.    

Tags: easy