In X, the windows have an optional decoration by security classification.
When you try to copy or paste from a high-security compartment to a low-security one, you get a pop-up saying this is a bad thing.
If needed, there is a "downgrader" that can copy to low-security on a case-by-case basis. Compilers can have an automatic downgrader for their object output, for example.
For safety, you could also have a popup when you try to copy from a low-safety compartment to a secure one, with a dwngrade to convert, for example, macro-virused word processor docs to macro-free filtered odf (;-))
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds