[jcantero]

I fail to see how it can help in this case. The most fine-grained access you can achieve with SELinux are objects such as files or ports. What you need here is the ability to check if the other process has the permission to invoke certain operations from the current server through the Wayland protocol. It would be like arbitrary capabilities, but not linked to the operating system but to specific applications.

For example, in order for the Color Picker Tool to work, The Gimp should be marked with a "color picked allowed" capability, so when it asks the Wayland server for the color of pixels outside the surfaces it already owns, the server can check it and send the requested info. But a rogue program/process trying to scrap the screen content pixel by pixel shouldn't be able to do that. The inability to safely map processes to executables in Unix (and the possibility of manipulating their running code via exec(), library injection, ...) make it a very hard problem to solve without a paradigm shift that SELinux doesn't provide (as far as I can tell).

[alien_at_work]

Oh I see. Yes, I don't think SELinux could do exactly the scenario you decide because the things you're mentioning don't exist at the OS level. If you can figure out a way to make them something SELinux can get a context onto then it would be possible.