Vue lecture

Domas: Bypassing memory protection with AMD's memory controllers

✇LWN
Par : daroc

Christopher Domas has published a proof of concept with a description showing how to use AMD memory controllers' bank swizzle mode to bypass memory protection and read or write arbitrary data, including CPU microcode definitions and memory belonging to the platform security processor. Among other things, this allows code running at the kernel level to directly manipulate the meaning of processor instructions, potentially bypassing other security measures such as memory encryption and virtual machine isolation.

This is not, strictly, unexpected behavior: it is documented in AMD's manual (on page 113 of that PDF). But the fact that it can be used to access arbitrary memory and thereby rewrite supposedly immutable parts of the computer's firmware without crashing the host machine seems like an unintentional side-effect of the design. Fortunately, since enabling bank swizzle mode requires kernel-level privileges, the vulnerability is not an immediate problem for most software. Still, it seems likely that this technique will end up being used for nefarious purposes eventually.

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rsync 3.5.0 released

✇LWN
Par : jzb

Version 3.5.0 of rsync has been released with a huge number of security fixes:

This release fixes 33 security issues found during a focused audit of rsync's path handling and daemon protocol, a companion daemon-protocol fuzzing pass, and reports from external researchers -⁠-⁠ plus several robustness hardenings. CVE IDs were assigned by VulnCheck (CNA); the precise "introduced in" version ranges accompany each advisory, and many are much narrower than "everything before 3.5.0". Every fix ships with a regression test in the test suite that fails on the unfixed tree.

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[$] 128-Bit page tables for Arm

✇LWN
Par : corbet
The size of a processor's page-table entries directly limits how much physical memory that processor is able to access. Back in the 32-bit days, that limit was 4GB, an amount of memory that once seemed nearly infinite, but which would now struggle to hold a basic AI-enabled "hello world" app. The expansion to 64 bits on most popular architectures would seem to have removed those limits now; some Arm systems, for example, can use 56 of those bits to access up to 72PB of memory. So it might be surprising that the Arm architecture is evolving to support even larger page-table entries (PTEs). This patch set from Anshuman Khandual adds support for 128-bit PTEs, but who will benefit from this capability is not entirely clear.
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Security updates for Thursday

✇LWN
Par : jzb
Security updates have been issued by AlmaLinux (abrt, dhcpcd, edk2, freerdp, gegl04, grafana, gstreamer1-plugins-good, iscsi-initiator-utils, isns-utils, kernel, kernel-rt, keylime, libarchive, libyang, nodejs-nodemon, opencryptoki, osbuild-composer, pacemaker, postgresql-jdbc, postgresql18, python-idna, python3.9, udisks2, valkey, vim, xorg-x11-server-Xwayland, and yggdrasil-worker-package-manager), Debian (flatpak, lemonldap-ng, neutron, python-django, spip, xdg-dbus-proxy, and xorg-server), Fedora (apr-util, cri-o1.34, libcupsfilters, linux-firmware, sqlite, and vaultwarden), Gentoo (FreeType), Oracle (dovecot, evince, fence-agents, gnutls, gstreamer1-plugins-bad-free, gstreamer1-plugins-good, isns-utils, java-1.8.0-openjdk, kernel, libarchive, osbuild-composer, pipewire, postgresql, ruby, ruby:3.3, sudo, and udisks2), Red Hat (bind, bind9.16, gnome-remote-desktop, grafana, opentelemetry-collector, python-pillow, python3, python3.12, python3.14, python3.9, and rhc), SUSE (chromium, clusterctl, dracut, gd, git-cliff, gleam, govulncheck-vulndb, graphicsmagick, gzip, kernel, kubevirt, libheif, librest0_7, nodejs22, nodejs24, openssh, openvpn, python3, python313-scikit-learn, rpm, stunnel, and zk), and Ubuntu (kernel, libgit2, linux, linux-aws, linux-aws-fips, linux-azure, linux-azure-6.8, linux-azure-fde, linux-azure-fde-6.8, linux-azure-fips, linux-fips, linux-gcp, linux-gcp-6.8, linux-gcp-fips, linux-gke, linux-gkeop, linux-ibm, linux-ibm-6.8, linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency, linux-realtime, linux-realtime-6.8, linux-xilinx, linux, linux-aws, linux-aws-fips, linux-azure, linux-azure-fde, linux-azure-fips, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iot-realtime, linux-intel-iotg, linux-intel-iotg-5.15, linux-kvm, linux-nvidia, linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-oracle-5.15, linux-realtime, linux-xilinx-zynqmp, linux, linux-aws, linux-aws-fips, linux-azure-4.15, linux-azure-fips, linux-fips, linux-gcp-4.15, linux-gcp-fips, linux-kvm, linux, linux-aws, linux-azure, linux-azure-fde, linux-ibm, linux-oracle, linux-raspi, linux-realtime, linux-azure, linux-azure-6.17, linux-gcp-6.17, linux-hwe-6.17, linux-oem-6.17, linux-realtime-6.17, node-follow-redirects, and yelp).
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[$] LWN.net Weekly Edition for August 13, 2026

✇LWN
Par : jzb
Inside this week's LWN.net Weekly Edition:

  • Front: BPF and binfmt_misc; CrossPoint ebook firmware; KVM planes; BPF formal verification; shadow-utils; new storage-code testing features.
  • Briefs: Django releases; GNOME shell; LightDM 1.33.0; QEMU 11.1; uutils 0.10; Software Stewardship Lab; Quotes; ...
  • Announcements: Newsletters, conferences, security updates, patches, and more.
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[$] Block-layer error injection

✇LWN
Par : daroc

Storage code has to cope with hardware that fails in inconvenient ways, but coaxing a healthy disk into producing those failures on demand, for testing, is usually not possible. The kernel provides several ways to inject block-layer I/O errors, but none of those can select the operation to fail, pick the status code to return, or target a disk directly without employing a stacked device on top. Use of a stacked device means the test runs against the mapper device, not the disk it was meant to exercise. A patch series from Christoph Hellwig adds a configurable error-injection interface that does all three things that the current error-injection code lacks, controlled by a per-disk debugfs file.

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[$] A look at CrossPoint e-reader firmware

✇LWN
Par : jzb

There are a number of small, inexpensive, low-powered e-reader or e-paper devices that have promise as ebook readers with one minor problem: the firmware they ship with does not realize their full potential. To solve that problem, the CrossPoint Reader project looks to provide replacement firmware that offers necessary features, better performance, and a more pleasant reading experience. On August 7, the project released version 1.5.0, which opens large EPUBs more quickly, provides offline dictionary lookups, and has reworked settings for changing layout and font options. The release also improves support for right-to-left text as well as Chinese, Japanese, and Korean (CJK) text rendering.

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QEMU 11.1 released

✇LWN
Par : jzb

Version 11.1 of the QEMU emulator has been released. The release contains more than 3,200 commits from 285 authors and includes a long list of improvements; see the announcement and changelog for the details.

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Security updates for Wednesday

✇LWN
Par : jzb
Security updates have been issued by AlmaLinux (fence-agents, firefox, frr10, gstreamer1-plugins-good, iscsi-initiator-utils, isns-utils, kernel, kernel-rt, perl-DBI:1.641, postgresql, postgresql:12, and resource-agents), Debian (libgd2, openjdk-25, php7.4, php8.2, and postfix), Fedora (clamav, domoticz, and libidn), Red Hat (delve, edk2, firefox, go-fdo-client, go-fdo-server, grafana, host-metering, ignition, kernel, kernel package, kernel-rt, ldns, libarchive, mariadb10.11, mariadb:10.11, multiple packages, rhc, rhc-worker-playbook, rhc-worker-script, sssd, thunderbird, yggdrasil, and yggdrasil-worker-package-manager), Slackware (expat and openssh), and SUSE (avahi, chromedriver, erlang26, gawk, glib2, go-sendxmpp, google-guest-agent, google-osconfig-agent, gpg2, gstreamer-plugins-bad, gstreamer-plugins-base, helm, ignition, ImageMagick, java-11-openj9, java-17-openj9, java-1_8_0-openj9, java-21-openj9, java-25-openj9, libarchive, libkrun, libpcp-devel, libpng16, libssh, libssh2_org, multipath-tools, net-tools, nmap, openssl-1_1, openssl-3, pcp, perl, python-pip, python-pyasn1, python-urllib3, python3-pip, python313-Django5, runc, samba, snpguest, spice-vdagent, sssd, unbound, wget, wild, wpa_supplicant, xmlrpc-c, and zpaqfranz).
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[$] KVM planes head for takeoff

✇LWN
Par : corbet
Virtualization places a guest system into a separate security domain, typically with fewer privileges than software running directly on the host. Increasingly, there is interest in creating multiple security domains within a single virtualized system as well. CPU vendors (and software vendors too) are implementing solutions; each of which, of course, is different from all of the others. KVM planes, currently under development by Jörg Rödel, Paolo Bonzini, and others in the KVM community, is an attempt to provide an abstraction layer that makes all of these features available on Linux systems; it is not a small task.
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Bernard: GNOME Shell design dreams

✇LWN
Par : jzb

GNOME contributor Tobias Bernard has published a blog post that details some of the design team's ideas for the GNOME Shell over the long term:

Some of these we have relatively complete plans for, others are more vague ideas that need more research and prototyping. As always, getting things like these implemented depends on developer capacity and interest (and sometimes funding).

While each of these ideas may require additional discussion, prototyping, and testing, we (the design team) have collected them all together here to share our longer-term vision and to give each idea more visibility.

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Security updates for Tuesday

✇LWN
Par : jzb
Security updates have been issued by AlmaLinux (gpsd), Debian (caddy, libyaml-syck-perl, nss, and wordpress), Fedora (chezmoi, chromium, emacs, kernel, knot, libcupsfilters, mingw-gstreamer1-plugins-good, mingw-libidn, mingw-python-pip, nghttp2, p11-kit, python-webob, suricata, and xen), Mageia (bind, openslide, php8.4, and php8.5), Oracle (gpsd-minimal, kernel, libarchive, libpng12, nodejs-nodemon, php:8.3, ruby:3.3, and ruby:4.0), SUSE (agama-web-ui, bind, bouncycastle, dhcpcd, ffmpeg, ffmpeg-4, freerdp, gd, gitoxide, kak-lsp, kernel-devel, librest-1_0-0, libsdb2_5_0, libssh2_org, nodejs22, PackageKit, perl, perl-Date-Manip, python-ujson, python3-sqlparse, python311, python312, python313-pymongo, ruby2.5, runc, suseconnect-ng, thunderbird, vlang, webkit2gtk3, and weechat), and Ubuntu (imagemagick and systemd).
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[$] Even more formal verification for BPF

✇LWN
Par : daroc

BPF offers useful safety guarantees, but Kumar Kartikeya Dwivedi wants BPF programs to be even safer. At the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit, he led a session (slides) discussing the possibility of adding domain-specific invariants to BPF programs. It was not a discussion intended to lead to the implementation of any particular kernel feature, but rather an overview of why additional formal verification might be needed, and how it could work with the existing BPF ecosystem.

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Django moves to an annual release cycle

✇LWN
Par : jzb

The Django Python web-framework project has announced that it has accepted an annual release cycle proposal. This means that the project is moving from a somewhat complicated schedule that interspersed short-lived feature releases and long-term-support (LTS) releases to a simpler annual cycle where each release is supported for three years.

Every feature release gets three years of support: one year of mainstream bugfixes, then two years of security and data-loss fixes. The "LTS" label is retired — every feature release now carries that same, unique commitment.

No more LTS gap: no racing a deadline to jump two years of changes at once. Upgrade one year at a time, whenever suits you within the support window. Three versions are supported at any time, giving third-party packages a clear, rolling target.

This will take effect with the upcoming Django 2028 release, expected in January 2028.

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Security updates for Monday

✇LWN
Par : jzb
Security updates have been issued by AlmaLinux (firefox, gpsd-minimal, kernel, libarchive, libgcrypt, and LibRaw), Debian (bind9, ca-certificates, chromium, dnsdist, icinga2, kitty, libheif, openjdk-21, pdns, pdns-recursor, thunderbird, and xen), Fedora (bird, erlang, kernel, mingw-glib2, nghttp2, p11-kit, perl, perl-Devel-Cover, perl-PAR-Packer, pgadmin4, polymake, python-nh3, python-wsgidav, python3.12, rabbitmq-server, rust-ammonia, seamonkey, and udisks2), Mageia (python-starlette), Oracle (gnutls, kernel, and LibRaw), Red Hat (container-tools:rhel8), Slackware (wpa_supplicant), and SUSE (azure-storage-azcopy, bouncycastle, ffmpeg-4, fuse-overlayfs, gleam, gstreamer-plugins-bad, libssh2-1, libssh2_org, libwireshark19, libXfont2-2, perl-Mojo-JWT, perl-Mojolicious, podman, python310, python313-Django4, and tekton-cli).
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Kernel prepatch 7.2-rc7

✇LWN
Par : corbet
The 7.2-rc7 kernel prepatch is out for testing. It is still bigger than Linus would like, but he said nonetheless: "I don't currently see any value in delaying the 7.2 release, so I would expect that to happen next weekend unless something really bad pops up."
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[$] Changes in shadow-utils password-expiration features

✇LWN
Par : jzb

The shadow-utils project provides the tools that handle /etc/shadow, /etc/passwd, and other related databases; in general, it manages users and groups on many Linux systems. While most software releases are notable for what is added, the recent shadow-utils 4.20.0 release is most noteworthy for what has been removed. Specifically, several utilities and functionality related to periodic password expiry, which were deprecated in the December 2025 4.19.0 release, have been removed as planned. It is still possible to manage some aspects of password aging with shadow-utils, but organizations that depend on such features should start planning for their complete removal within a few years.

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The Software Stewardship Lab launches

✇LWN
Par : corbet
The Software Stewardship Lab, a nonprofit organization based in Scotland, has announced its existence.

Our current research focuses are:

  • Software supply chain security — We're working on an observatory that allows users to identify and monitor the world's critical Open Source packages in real time, including previously hidden parts of the dependency graph.
  • Maintainer burnout — Our report on burnout in Open Source has been well-received. We're working on yearly follow-ups, plus a companion report on how AI is affecting maintainer burnout.

Moving forward, the Lab's experts will direct funding to and supervise Open Source sustainability researchers doing critical work. We are already working with universities to teach the next generations of software supply chain experts.

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LightDM lives: version 1.33.0 released

✇LWN
Par : jzb

Version 1.33.0 of the LightDM display manager has been released. This is the first release in four years: the project had been sponsored by Canonical but was effectively unmaintained in recent years. It has been transferred to a new community repository and is now maintained by Joshua Peisach and Neal Gompa.

The new release includes Qt6 support, code optimizations, and a list of other fixes that had been in limbo pending a new release.

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