Simplicity is a form of art...

SELinux User-Based Access Control

Within the reference policy, support is given to a feature called UBAC constraints. Here, UBAC stands for User Based Access Control. The idea behind the constraint is that any activity between two types (say foo_t and bar_t) can be prohibited if the user contexts of the resources that are using …

SELinux and noatsecure, or why portage complains about LD_PRELOAD and libsandbox.so

If you're fiddling with SELinux policies, you will eventually notice that the reference policy by default hides certain privilege requests (which are denied). One of them is noatsecure. But what is noatsecure? To describe noatsecure, I first need to describe what atsecure is. And to describe what that is, we …

Updates on SELinux docs, added FAQ

As you're probably noticing from my twitter feed and the various posts earlier in my blog, I'm helping out with the Gentoo Hardened folks to get the SELinux support state up to par. Today, the Gentoo Hardened/SELinux Handbook had a few updates, but the most important change is that …

Portage fails to build due to SELinux?

If you're having troubles getting Portage to build packages due to SELinux, then the reason usually is that it is unable to transition to the proper portage domains. You'll get a nice OSError back with an ugly backtrace, saying somewhere that "setexeccon" is misbehaving.

Now, the real issue (not being …

Temporary script for Gentoo Hardened SELinux users

If you are currently using Gentoo Hardened with SELinux, you might have noticed that we are currently lacking the proper dependencies within our Portage tree upon the SELinux policies (or, in other words, installing a package doesn't guarantee that the SELinux policy needed for that package is pulled in as …

SELinux for Gentoo Hardened

Recently, most of the SELinux-related ebuilds from the hardened overlay have been moved to the official Portage tree. Hopefully, this will trigger more people / organizations to try Gentoo Hardened with SELinux and help us improve the ebuilds. They're still marked as \~arch (as they should be). The draft SELinux handbook …

Confining user applications

Ever since I started using SELinux, I'm getting more and more fond of what it can do for (security) administrators. Lately, I've started confining user applications (like skype) in the idea that I do not want any application connecting to the Internet or working with content received from untrusted sources …

SELinux enforcing for console activity

I'm now able to boot into my system with SELinux in enforcing mode (without unconfined domains), do standard system administration tasks as root / sysadm_r (including the relevant Portage activities) and work as a regular user as long as I don't want to run in Xorg. I'm not going to focus …

SELinux quicky

I've been using SELinux for a few days now (in permissive mode, just to get to know things) and have learned a few interesting commands (or other nice-to-know's) for using SELinux. Since I'm going to forget those the moment all is running well, I'll "document" them here ;-) I'm not going …