Re: [Full-disclosure] Symlink vulnerabilities



On Sat, 22 Oct 2011 01:23:34 EDT, Byron Sonne said:
If you are in charge of a distro, it would not hurt to nuke it
altogether and change all packages in your control to use per-user
$TMPDIR. Some third-party stuff will break - but it breaks every now
and then anyway.

Excellent suggestion, and you've piqued my curiosity. What distros exist
that implement tmp dirs in such a way? I haven't come across any, and
the more I think about it, the more I wish that this is something I
would see.

Fedora's had the pam_namespace stuff for a while now - it got added about
the same time as SELinux. It's also in RHEL 5 and later. It also appears to
be in current Ubuntu and SLES 11.1.

So it's a good question of what distros *don't* have the tools to implement this?

Why they don't do it by default? Because if you screw up the config, things break
in strange and mysterious ways. Those of you old enough to remember the first
2-3 years of "/etc/shadow is a separate file from /etc/passwd", or even further
back to when the Sun-3 created "Not all the world's a Vax", know why distros aren't
enabling it by default yet. But in 2-3 years, probably...

If you had your way, would you see it implemented as /tmp/<USER>
/<USER>/tmp, or some other way?

It should be site-configurable - some places may have a large fast /tmp area
and they want a per-user directory on that disk space. Other places may want
to have /tmp redirected to /home/${USER}/tmp so disk quotas apply, etc etc.


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