Linux Weekly News

Version 2.39 of the GNU C Library has been released. Changes include integration with the x86 shadow-stack mechanism, a couple of new posix_spawn() variants for working with control groups, pidfd_spawn() and pidfd_spawnp(), the C2X stdbit.h header, the removal of the libcrypt library, and more. See the release notes for details.

Version 24.2 of the LibreOffice office suite is available. Changes include AutoRecovery enabled by default, styling of comments, better floating-table support, improved accessibility, and more. See the release notes for details.

Return-oriented programming (ROP) attacks are hard to defend against. Partial mitigations such as address-space layout randomization, stack canaries, and other techniques are commonly deployed to try and frustrate ROP attacks. Now, OpenBSD is experimenting with a new mitigation that makes it harder for attackers to make system calls, although some security researchers have expressed doubt that it will prove effective at stopping real-world attacks. In his announcement message, Theo de Raadt said that this work "makes some specific low-level attack methods unfeasable on OpenBSD, which will force the use of other methods."

Qualys has disclosed a vulnerability in the GNU C Library that can be exploited by a local attacker for root access. It was introduced in the 2.37 release, and also backported to 2.36.

For example, we confirmed that Debian 12 and 13, Ubuntu 23.04 and 23.10, and Fedora 37 to 39 are vulnerable to this buffer overflow. Furthermore, we successfully exploited an up-to-date, default installation of Fedora 38 (on amd64): a Local Privilege Escalation, from any unprivileged user to full root. Other distributions are probably also exploitable.

Vulnerable systems with untrusted users should probably be updated in a timely manner.

Security updates have been issued by Debian (bind9 and glibc), Fedora (ncurses), Gentoo (containerd, libaom, and xorg-server, xwayland), Mageia (python-pillow and zlib), Oracle (grub2 and tomcat), Red Hat (avahi, c-ares, container-tools:3.0, curl, firefox, frr, kernel, kernel-rt, kpatch-patch, libfastjson, libmicrohttpd, linux-firmware, oniguruma, openssh, perl-HTTP-Tiny, python-pip, python-urllib3, python3, rpm, samba, sqlite, tcpdump, thunderbird, tigervnc, and virt:rhel and virt-devel:rhel modules), SUSE (python-Pillow, slurm, slurm_20_02, slurm_20_11, slurm_22_05, slurm_23_02, and xen), and Ubuntu (libde265, linux-nvidia, mysql-8.0, openldap, pillow, postfix, and xorg-server, xwayland).

EmacsConf 2023 was, like its recent predecessors, an online conference with lots of talks about various aspects of the Emacs editor—though, of course, it is way more than just an editor. Last year's edition was held in early December. One of the talks that looked interesting was on Emacs development, which was given live by John Wiegley. In it, he briefly described some of the biggest features coming in Emacs 30, which is the next major version coming for the tool.

The eBPF Foundation has published a glossy document called The State of eBPF; it seems mostly concerned with how a small number of large companies are using and developing this technology.

No doubt, eBPF will become the new layer in the new cloud native infrastructure stack, impacting the observability, performance, reliability, networking, and security of all applications, supporters say. Platform engineers will cobble together eBPF-powered infrastructure building blocks to create platforms that developers then deploy software on, adding business logic to the mix, and replacing aging Linux kernel internals that cannot keep up with today’s digital and, increasingly, cloud native world.

Security updates have been issued by Debian (pillow, postfix, and redis), Fedora (python-templated-dictionary and selinux-policy), Red Hat (gnutls, kpatch-patch, libssh, and tomcat), and Ubuntu (amanda, ceph, linux-azure, linux-azure-4.15, linux-kvm, and tinyxml).

In December, the Rust project released a call for proposals for inclusion in the 2024 edition. Rust handles backward incompatible changes by using Editions, which permit projects to specify a single stable edition for their code and allow libraries written in different editions to be linked together. Proposals for Rust 2024 are now in, and have until the end of February to be debated and decided on. Once the proposals are accepted, they have until May to be implemented in time for the 2024 edition to be released in the second half of the year.

Security updates have been issued by CentOS (gstreamer-plugins-bad-free, java-1.8.0-openjdk, java-11-openjdk, kernel, LibRaw, python-pillow, and xorg-x11-server), Debian (gst-plugins-bad1.0, libspreadsheet-parsexlsx-perl, mariadb-10.3, and slurm-wlm), Fedora (atril, dotnet8.0, gnutls, prometheus-podman-exporter, python-jinja2, sudo, and vips), Oracle (frr, kernel, php:8.1, python-urllib3, python3.9, rpm, sqlite, and tomcat), Slackware (pam), SUSE (cpio, rear23a, rear27a, sevctl, and xorg-x11-server), and Ubuntu (exim4 and firefox).

Linus has released 6.8-rc2 for testing. "So go out and test. It's safe now. You trust me, right?"

While the mathematical realm of numbers is infinite, computers are only able to represent a finite subset of them. That can lead to problems when arithmetic operations would create numbers that the computer is unable to store as the intended type. This condition, called "overflow" or "wraparound" depending on the context, can be the source of bugs, including unpleasant security vulnerabilities, so it is worth avoiding. This patch series from Kees Cook is intended to improve the kernel's handling of these situations, but it is running into a bit of resistance.

Security updates have been issued by Debian (xorg-server), Fedora (chromium, dotnet8.0, firefox, freeipa, and thunderbird), Red Hat (avahi, c-ares, curl, edk2, expat, freetype, frr, git, gnutls, grub2, kernel, kernel-rt, libcap, libfastjson, libssh, libtasn1, libxml2, linux-firmware, ncurses, oniguruma, openssh, openssl, perl-HTTP-Tiny, protobuf-c, python-urllib3, python3, python3.9, rpm, samba, shadow-utils, sqlite, tcpdump, tomcat, and virt:rhel and virt-devel:rhel modules), SUSE (cpio, jasper, rear23a, thunderbird, and xorg-x11-server), and Ubuntu (jinja2, kernel, linux, linux-aws, linux-aws-5.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gkeop, linux-gkeop-5.15, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-kvm, linux-lowlatency-hwe-5.15, linux-raspi, linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-bluefield, linux-gcp, linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4, linux-iot, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4, linux-xilinx-zynqmp, linux, linux-aws, linux-aws-6.2, linux-azure, linux-azure-6.2, linux-azure-fde-6.2, linux-gcp, linux-hwe-6.5, linux-laptop, linux-lowlatency, linux-lowlatency-hwe-6.5, linux-oem-6.5, linux-oracle, linux-raspi, linux-starfive, linux, linux-aws, linux-aws-hwe, linux-gcp, linux-gcp-4.15, linux-hwe, linux-kvm, linux-oracle, linux, linux-aws, linux-kvm, linux-lts-xenial, linux-aws, linux-azure, linux-azure-5.15, linux-azure-fde, linux-azure-fde-5.15, linux-oem-6.1, and mariadb, mariadb-10.3, mariadb-10.6).

Greg Kroah-Hartman has announced the release of the 6.7.2, 6.6.14, 6.1.75, 5.15.148, 5.10.209, 5.4.268, and 4.19.306 stable kernels. As usual, they contain a long list of fixes throughout the kernel tree.

The free-software community has managed to build a body of software that is worth, by most estimates, many billions of dollars; all of this code is freely available to anybody who wants to use or modify it. It is an unparalleled example of independent actors working cooperatively on a common resource. Free software is certainly a success story, but all is not perfect. One of the community's greatest strengths — convincing companies to contribute to this common resource — is also part of one of its biggest weaknesses.

The AdaCore blog describes some hardening features contributed to GCC for the GCC 14 release.

With -fharden-control-flow-redundancy, the compiler now verifies, at the end of functions, whether the traversed basic blocks align with a legitimate execution path. The purpose of this protective measure is to detect and thwart attacks attempting to infiltrate the middle of functions, thereby enhancing the overall security posture of the compiled code.

Security updates have been issued by Debian (chromium, firefox-esr, php-phpseclib, phpseclib, thunderbird, and zabbix), Fedora (dotnet7.0, firefox, fonttools, and python-jinja2), Mageia (avahi and chromium-browser-stable), Oracle (java-1.8.0-openjdk, java-11-openjdk, LibRaw, openssl, and python-pillow), Red Hat (gnutls, kpatch-patch, php:8.1, and squid:4), SUSE (apache-parent, apache-sshd, bluez, cacti, cacti-spine, erlang, firefox, java-11-openjdk, opera, python-Pillow, tomcat, tomcat10, and xwayland), and Ubuntu (paramiko and puma).

The LWN.net Weekly Edition for January 25, 2024 is available.

Python packaging discussions seem like they often just go around and around, ending up where they started and recapitulating many of the points that have come up before. A recent discussion revolves around the pip package installer, as they often do. The central role that is occupied by pip has both good points and bad. There is a clear need for something that can install from the Python Package Index (PyPI) immediately after Python itself is installed. Whether there should be additional features, including project management, that come "inside the box", as well, is much less clear—not unlike the question of which project management "style" should be chosen.

Security updates have been issued by Debian (jinja2, openjdk-11, ruby-httparty, and xorg-server), Fedora (ansible-core and mingw-jasper), Gentoo (GOCR, Ruby, and sudo), Oracle (gstreamer-plugins-bad-free, java-17-openjdk, java-21-openjdk, python-cryptography, and xorg-x11-server), Red Hat (kernel, kernel-rt, kpatch-patch, LibRaw, python-pillow, and python-pip), Slackware (mozilla), SUSE (python-Pillow, rear118a, and redis7), and Ubuntu (libapache-session-ldap-perl and pycryptodome).