As of this writing, 5,546 non-merge changesets have been pulled into the mainline
kernel repository for the 6.16 release. This is a bit less than half of the
total commits for 6.15, so the merge window is well on its way. Read on for our
summary of the first half of the 6.16 merge window.
As the end of the 1990s approached, a lot of kernel-development effort was
going into improving support for 32-bit systems
with shockingly large amounts of memory installed. This being the 1990s,
having more than 1GB of memory in such a system was deemed to be shocking.
Many of the compromises made to support such inconceivably large systems
have remained in the kernel to this day. One of those compromises —
bounce buffering of I/O requests in the block layer — has finally been
eased out for the 6.16 release, more than a quarter-century after its
introduction.
The SUSE Security Team has published a detailed
report about security vulnerabilities it discovered in the Kea DHCP server suite from the Internet Systems Consortium
(ISC).
Since SUSE is also going to ship Kea DHCP in its products, we
performed a routine review of its code base. Even before checking the
network security of Kea, we stumbled over a range of local security
issues, among them a local root exploit which is possible in many
default installations of Kea on Linux and BSD distributions. [...]
This report is based on Kea release 2.6.1. Any source code
references in this report relate to this version. Many systems still
ship older releases of Kea, but we believe they are all affected as
well by the issues described in this report.
The report details seven security issues including
local-privilege-escalation
and arbitrary file overwrite
vulnerabilities. Security fixes for the vulnerabilities have been
published in all of the currently supported release series of Kea: 2.4.2,
2.6.3,
and the 2.7.9
development release were all released on May 28. Kea has assigned CVE-2025-32801,
CVE-2025-32802,
and CVE-2025-32803 to the vulnerabilities. Note that some of the CVEs
cover multiple security flaws.
The
6.14.9 and
6.12.31 stable kernels have been released.
Each contains an unusually large number of important fixes all over the
kernel tree.
Security updates have been issued by AlmaLinux (kernel and kernel-rt), Debian (firefox-esr, libvpx, net-tools, php-twig, python-tornado, setuptools, varnish, webpy, yelp, and yelp-xsl), Fedora (xen), Mageia (cimg and ghostscript), Oracle (gstreamer1-plugins-bad-free, kernel, libsoup, thunderbird, and unbound), Red Hat (firefox, mingw-freetype and spice-client-win, pcs, and varnish:6), Slackware (curl and mozilla), SUSE (apparmor, containerd, dnsdist, go1.23-openssl, go1.24, gstreamer-plugins-bad, ImageMagick, jetty-minimal, python-tornado, python313-setuptools, s390-tools, thunderbird, tomcat10, ucode-intel, and wxWidgets-3_2), and Ubuntu (ffmpeg, krb5, libsoup3, libsoup2.4, linux-aws-5.4, linux-aws-fips, linux-fips, linux-oracle-6.8, net-tools, and python-setuptools, setuptools).
Inside this week's LWN.net Weekly Edition:
- Front: Glibc security; How we lost the Internet; Encrypted DNS; 6.15 Development statistics; Filesystem stress-testing; BPF verifier; Network access from BPF; OSPM 2025.
- Briefs: AlmaLinux 10.0; FESCo decision overturned; NixOS 25.05; Pocket, Launchpad retired; Quotes; ...
- Announcements: Newsletters, conferences, security updates, patches, and more.
The GNU C Library
(glibc) is the core C library for most Linux distributions, so it is a
crucial part of the open-source ecosystem—and an attractive
target for any attackers looking to carry out supply-chain
attacks. With that being the case, securing the project's
infrastructure using industry best practices and improving the
security of its development practices are a frequent topic among glibc
developers. A recent discussion suggests that improvements are not
happening as quickly as some would like.
Mahé Tardy led two sessions about some of the challenges that he, Kornilios Kourtis,
and John Fastabend have run into in their work on
Tetragon (Apache-licensed BPF-based security monitoring software)
at the Linux Storage, Filesystem, Memory Management, and BPF Summit. The session
prompted discussion about the feasibility of letting BPF programs
send data over the network, as well as potential new kfuncs to let BPF firewalls
send TCP reset packets. Tardy presented several possible ways that these could
be accomplished.
Canonical's Launchpad
software-collaboration platform that is used for Ubuntu development
will be shutting down its hosted mailing lists at
the end of October. The announcement
recommends Discourse or Launchpad Answers as
alternatives. Ubuntu's mailing
lists are unaffected by the change.
The increasing sophistication of attackers has organizations
realizing that perimeter-based security models are inadequate. Many
are planning to transition their internal networks to a zero-trust
architecture. This requires every communication on the network to
be encrypted, authenticated, and authorized. This can be achieved in
applications and services by using modern communication
protocols. However, the world still depends on Domain Name System
(DNS) services where encryption, while possible, is far from being the
industry standard. To address this we, as part of a working group at
Red Hat, worked on fully integrating encrypted DNS for Linux
systems—not only while the system is running but also during the
installation and boot process, including support for a custom
certificate chain in the initial ramdisk. This integration is now
available in CentOS Stream 9, 10, and the upcoming
Fedora 43 release.