5 articles from LWN.net
The SUSE Security Team Blog has a post with an analysis of seunshare, which is used by SELinux to confine untrusted programs. During a review of version 3.10 of the program, the team identified two l…
The SUSE Security Team Blog has a post with an analysis of seunshare, which is used by SELinux to confine untrusted programs. During a review of version 3.10 of the program, the team identified two local Denial-of-Service (DoS) vectors. Since seunshare is supposed to run on SELinux-enabled systems, it is important to understand what kind of privilege escalation can be achieved when vulnerabilities are exploited in a setuid-root binary like this. Many SELinux-enabled systems, such as Fedora and openSUSE, ship with the "targeted" SELinux policy by default. This policy is focused on confining well-known system services, but assigns an unconfined SELinux context to interactive users by default to achieve a balance between security and usability. There is currently no domain transition from the unconfined domain to the more restricted seunshare_t defined in the SELinux policy for seunshare. This means the execution of seunshare continues in the unconfined domain. Thus in the context of attacks carried out by interactive users, the impact of the vulnerabilities below will be a root-like privilege escalation despite the system running in SELinux enforced mode. See the post for the full write-up of the team's discoveries and timeline. The vulnerabilities have been fixed in version 3.11.
Processes that use io_uring tend to keep a lot of balls in the air; being able to have many operations underway at any given time is part of the point of that API in the first place. The io_uring sub…
Processes that use io_uring tend to keep a lot of balls in the air; being able to have many operations underway at any given time is part of the point of that API in the first place. The io_uring subsystem must, as a result, keep track of a lot of tasks that have to be performed at the right time. In current kernels, io_uring uses a standard kernel linked-list primitive to track those work items. As of the 7.2 kernel release, though, io_uring will, instead, use a new lockless, multi-producer, single-consumer (MPSC) queue, resulting in some notable performance gains. Lockless algorithms tend to be tricky, but the one used here is relatively approachable and shows how these algorithms can work.
Security updates have been issued by AlmaLinux (cifs-utils, corosync, cups, freerdp, git-lfs, go-fdo-client and go-fdo-server, go-toolset:rhel8, kernel, kernel-rt, libinput, libxml2, nginx:1.24, open…
Security updates have been issued by AlmaLinux (cifs-utils, corosync, cups, freerdp, git-lfs, go-fdo-client and go-fdo-server, go-toolset:rhel8, kernel, kernel-rt, libinput, libxml2, nginx:1.24, openssl, pacemaker, perl-DBI:1.641, php8.4, python-pillow, python3, and python3.12), Debian (grub2, libxfont, opam, and wolfssl), Fedora (freerdp, kernel, and prometheus), Mageia (imagemagick), Oracle (buildah, freerdp, gimp, kernel, nginx, openexr, openssl, perl-DBI, podman, vim, xorg-x11-server, and xorg-x11-server-Xwayland), Red Hat (python3.12), SUSE (afterburn, buildah, busybox, enc, freetype2-devel, go1.25, go1.25-openssl, go1.26-openssl, gosec, grafana, helm, krb5, kubernetes-old, libopenbabel8, libxml2, libxml2-16, nasm, openssl-3, patch, python-Authlib, python-mistune, python-soupsieve, python-sqlparse, python3-dulwich, python313-Pillow, rootlesskit, sbootutil-1, tomcat, and tomcat11), and Ubuntu (alsa-lib, dnsmasq, gnutls28, libheif, linux-aws, linux-fips, linux-lts-xenial, linux-gcp-5.15, linux-intel-iotg-5.15, linux-hwe-6.17, linux-raspi, mariadb, openvpn, python-httplib2, vim, and wget).
The CMU CERT Coordination Center has put out an advisory that many exploitable versions of the shim binary, used to boot Linux on systems with UEFI secure boot enabled, were never added to the revoca…
The CMU CERT Coordination Center has put out an advisory that many exploitable versions of the shim binary, used to boot Linux on systems with UEFI secure boot enabled, were never added to the revocation list. An attacker with administrative privileges or the ability to modify the boot process could use one of the vulnerable shim bootloaders to bypass Secure Boot protections and execute arbitrary code before the operating system loads. Code executed during this early boot phase may achieve persistent compromise of the platform, including the ability to load unsigned or malicious kernel components that can survive system reboots and, in some cases, operating system reinstallation. The advisory contains a list of vulnerable shims.
Rob Kennedy has posted the story of the birth of Linux.org — one of the earliest Linux-related web sites — and its more recent rebirth. The site was founded in May 1994 by Michael McLagan, at a time …
Rob Kennedy has posted the story of the birth of Linux.org — one of the earliest Linux-related web sites — and its more recent rebirth. The site was founded in May 1994 by Michael McLagan, at a time when Linux itself was barely three years old. Linus Torvalds had only just released it to the world, there was no real way for a newcomer to find their footing, no search engines, no Wikipedia, none of the infrastructure people take for granted now for figuring out a new piece of technology. Michael built linux.org to fill that gap, a place for people to learn about Linux and follow the movement as it grew.