Capabilities
Core Technology
Everyone wants to be root, because root can do anything. But in fact, its powers are now split. Learn more in this overview of capability sets.
Today's Linux is somewhat like a famous sightseeing city you might have visited on your last vacation. There is a historic part that's of no practical use now, yet it is what keeps the city's identity. There are some well-known tourist spots that everybody seems to visit. And, finally, there are some secluded locations you never find in an advertisement in a travel agency. These are places a friend living there would show you, and they are essential for sensing a real spirit of the city, not its pamphlet picturesque image.
Okay, maybe I've taken the analogy a bit too far here. But if you agree to follow it for a second, capabilities would be one of these secluded locations. Introduced with Linux 2.2, they are what really tells if process X can do Y. Yet they are often lost in shadows of traditional Unix privileges, SELinux, eBPF, and many others. By the end of this Core Tech article, you'll know who really sets your limits in a city of Linux.
An All-Mighty Root (Actually, Not)
Back in ye olde days, the permission system of Linux was pretty much simple. A user with UID 0 – often called "root" – could do any privileged operation, and he wasn't subject to permission checks. Note it is the UID, not the name, which is important. A user called "val" with UID 0 holds all powers of root user as well.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Linux Mint 22.2 Beta Available for Testing
Some interesting new additions and improvements are coming to Linux Mint. Check out the Linux Mint 22.2 Beta to give it a test run.
-
Debian 13.0 Officially Released
After two years of development, the latest iteration of Debian is now available with plenty of under-the-hood improvements.
-
Upcoming Changes for MXLinux
MXLinux 25 has plenty in store to please all types of users.
-
A New Linux AI Assistant in Town
Newelle, a Linux AI assistant, works with different LLMs and includes document parsing and profiles.
-
Linux Kernel 6.16 Released with Minor Fixes
The latest Linux kernel doesn't really include any big-ticket features, just a lot of lines of code.
-
EU Sovereign Tech Fund Gains Traction
OpenForum Europe recently released a report regarding a sovereign tech fund with backing from several significant entities.
-
FreeBSD Promises a Full Desktop Installer
FreeBSD has lacked an option to include a full desktop environment during installation.
-
Linux Hits an Important Milestone
If you pay attention to the news in the Linux-sphere, you've probably heard that the open source operating system recently crashed through a ceiling no one thought possible.
-
Plasma Bigscreen Returns
A developer discovered that the Plasma Bigscreen feature had been sitting untouched, so he decided to do something about it.
-
CachyOS Now Lets Users Choose Their Shell
Imagine getting the opportunity to select which shell you want during the installation of your favorite Linux distribution. That's now a thing.