Access control of Linux and Bell LaPadula Model

Question

I know that access control is a very important think when we want to protect our files and in security in general. Does anyone know what access control system is used by linux?

In addition I just found the Bell-LaPadula model, which I find very interesting as a model, as it has top-secret flags etc. Does anyone know if this model is used anywhere in practice? Or is it just theoretical?

In addition, If I want to have a Linux system to have very strong access control, and I want to use this model, does anyone knows what I have to do?

Answer 1

The system Bell and LaPadula describe exists in SE Linux, but is not used the way permissions and access-control lists are, but instead to limit the capabilities of programs, to avoid them leaking information. Something my phone needs!

As it stands, the system is logical, powerful and subtle. The latter two, together, means that it's easy to get wrong (:-)) One of the disfeatures is that if I'm in Top Secret and take a copy of something that's just secret, it gets copied into the top secret category. Eventually, everything on the system is in TS, with older copies laying around at lower levels.

I'm of the opinion that a specific, extremely simple subset could be used today to deal with some of out "spy" problems. The subset could avoid the above and other logical/logistical problems, and just do confidentiality between, for example, my bank and myself.

I have at talk at GTALUG about that, at http://gtalug.org/mediawiki/images/5/5e/SpyVsSpy.pdf

and there is a background article at http://broadcast.oreilly.com/2013/12/where-were-ye-orange-book-in-w.html/

Answer 2

The model is used in Multilevel Security (MLS) systems which provide trusted computing used by folks that have labels like the one you describe. In other words, the governments of the world. Wikipedia has some good links here

There are solutions available today that use the model. Some of those are listed in the article.