bug#6953: 24.0.50; serious security bug in create backup files

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Thu, 09 Sep 2010 23:06:46 -0400
> Cc: 6953@debbugs.gnu.org, Mark Diekhans <markd@soe.ucsc.edu>
> 
> Just had a thought that this kind of approach is not going to work for
> securing ~/%backup%~ files for people who have AFS home directories.
> Which probably is not many in % terms, but is more than zero. In AFS,
> the _only_ way to make files private to the owner is to put them in a
> private directory.
> 
> On the other hand, simply creating a mode 700 directory does not
> necessarily make it private, you have to use AFS commands to set ACLs.
> But the approach of having backup files in a special directory would
> be closer to how AFS normally works.

The situation on MS-Windows is almost exactly the same.  Files put in
private directories are private by default, but creating a new private
directory requires using Windows-specific ACL APIs.

Maybe it's time to have this functionality in Emacs.