Zack's Kernel News
Kernel News

Chronicler Zack Brown reports on the latest news, views, dilemmas, and developments within the Linux kernel community.
To Add Capsicum or Not To Add Capsicum
David Drysdale noticed that FreeBSD had a new security feature called Capsicum that might work well in Linux. He gave a link to a paper from the 19th USENIX Security Symposium in 2010 describing the project [1].
The idea was to implement fine-grained security privileges so that applications could isolate their own abilities and prevent an attacker from forcing them to do the wrong thing. David gave the example of tcpdump
constraining itself to read only from the network file descriptor and write only to standard output. An interesting aspect of this type of security is that the application must be aware of the security features provided by the operating system and include code to take advantage of them.
David posted some of his implementation ideas, but Eric W. Biederman felt that most of these were badly conceived. For example, Capsicum required that the kernel police the rights checks of file descriptors, and David thought that the best place to do that was in the code that converted a userspace file descriptor into a kernel space file pointer structure. This in turn, David said, would require implementing an extensive and invasive abstraction layer within the kernel code. However, Eric pointed out that the abstraction layer wasn't necessary, because filesystem "capabilities" had already existed for 20 years and (with some modifications) could perform a similar function.
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
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
-
System76 Releases COSMIC Alpha 7
With scores of bug fixes and a really cool workspaces feature, COSMIC is looking to soon migrate from alpha to beta.
-
OpenMandriva Lx 6.0 Available for Installation
The latest release of OpenMandriva has arrived with a new kernel, an updated Plasma desktop, and a server edition.
-
TrueNAS 25.04 Arrives with Thousands of Changes
One of the most popular Linux-based NAS solutions has rolled out the latest edition, based on Ubuntu 25.04.
-
Fedora 42 Available with Two New Spins
The latest release from the Fedora Project includes the usual updates, a new kernel, an official KDE Plasma spin, and a new System76 spin.
-
So Long, ArcoLinux
The ArcoLinux distribution is the latest Linux distribution to shut down.
-
What Open Source Pros Look for in a Job Role
Learn what professionals in technical and non-technical roles say is most important when seeking a new position.
-
Asahi Linux Runs into Issues with M4 Support
Due to Apple Silicon changes, the Asahi Linux project is at odds with adding support for the M4 chips.
-
Plasma 6.3.4 Now Available
Although not a major release, Plasma 6.3.4 does fix some bugs and offer a subtle change for the Plasma sidebar.
-
Linux Kernel 6.15 First Release Candidate Now Available
Linux Torvalds has announced that the release candidate for the final release of the Linux 6.15 series is now available.
-
Akamai Will Host kernel.org
The organization dedicated to cloud-based solutions has agreed to host kernel.org to deliver long-term stability for the development team.