All posts by jake

[$] Improving control-flow integrity for Linux on RISC-V

Post Syndicated from jake original https://lwn.net/Articles/977720/

Redirecting execution flow is a common malware
technique that can be used to compromise operating systems. To protect from such attacks,
the chip makers of leading architectures like x86 and arm64 have implemented
control-flow-integrity (CFI) extensions, though they need system
software support to function. At the Linux
Security Summit North America
, RISC-V kernel developer Deepak Gupta described the CFI
protections for that architecture and invited community input on the
kernel support for them.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/978291/

Security updates have been issued by Debian (firefox-esr), Fedora (nginx-mod-modsecurity, php, and tomcat), Mageia (strongswan), Oracle (389-ds-base, buildah, c-ares, cockpit, containernetworking-plugins, fence-agents, firefox, gdk-pixbuf2, idm:DL1, ipa, kernel, libreoffice, podman, rpm-ostree, and thunderbird), Red Hat (dnsmasq and nghttp2), Slackware (mozilla), SUSE (curl, firefox, kernel, kernel-firmware-nvidia-gspx-G06, nvidia-open- driver-G06-signed, openssl-3, and python-Pillow), and Ubuntu (libmatio, libndp, linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp,
linux-gcp-5.4, linux-gkeop, linux-hwe-5.4, linux-ibm, linux-ibm-5.4,
linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi, linux-raspi-5.4,
linux-xilinx-zynqmp, linux-oem-6.5, and virtuoso-opensource).

[$] Dropping the page cache for filesystems

Post Syndicated from jake original https://lwn.net/Articles/977486/

VFS maintainer Christian Brauner led a discussion about the possibility of
selectively dropping the contents of the page cache for a filesystem in a
session at the
2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
. As he described in his
topic
proposal
, the use case that started him down this path comes from
GNOME, which wants to be able to safely suspend access to an encrypted home
directory. While it is known to kernel
developers, it is surprising to others that reads from encrypted
filesystems that have been suspended will succeed if the data to be read
still exists in the
page cache.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/977789/

Security updates have been issued by Fedora (galera and mariadb10.11), Mageia (0-plugins-base and plasma-workspace), Oracle (ruby:3.1 and ruby:3.3), Red Hat (bind, bind-dyndb-ldap, and dhcp), SUSE (apache2, glib2, libvirt, openssl-1_1, openssl-3, opera, python-Jinja2, python-requests, and squid), and Ubuntu (linux, linux-gcp, linux-gcp-5.15, linux-lowlatency,
linux-lowlatency-hwe-5.15, linux-xilinx-zynqmp, linux, linux-gcp, linux-gcp-6.5, linux-lowlatency,
linux-lowlatency-hwe-6.5, linux-raspi, linux, linux-ibm, linux-lowlatency, linux-raspi, linux-aws, linux-gcp, linux-azure, linux-azure-6.5, linux-starfive, linux-starfive-6.5, and linux-gke, linux-ibm, linux-intel-iotg, linux-oracle).

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/977442/

Security updates have been issued by AlmaLinux (cockpit, kernel, kernel-rt, libxml2, ruby:3.1, and tomcat), Debian (libarchive, pillow, and tinyproxy), Fedora (apptainer), Mageia (amavisd-new and libxml2), Oracle (edk2), Red Hat (booth, cockpit, kernel-rt, less, libxml2, nghttp2, ruby:3.1, ruby:3.3, and tomcat), Slackware (kernel), and Ubuntu (atril, bluez, frr, gdk-pixbuf, openjdk-17, openjdk-21, openjdk-8, openjdk-lts, qemu, and unixodbc).

[$] Measuring and improving buffered I/O

Post Syndicated from jake original https://lwn.net/Articles/976856/

There are two types of file I/O on Linux, buffered I/O, which goes through
the page cache, and direct I/O, which goes directly to the storage device.
The performance of buffered I/O was reported to be a lot worse than direct
I/O, especially for one specific test, in Luis Chamberlain’s
topic
proposal
for a session at the 2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
.
The proposal resulted in a lengthy mailing-list discussion,
which also came up in Paul McKenney’s RCU session the next
day; Chamberlain led a
combined storage and filesystem session to discuss those results with an
eye toward improving buffered I/O performance.

[$] Removing GFP_NOFS

Post Syndicated from jake original https://lwn.net/Articles/976355/

The GFP_NOFS flag is meant for kernel memory allocations that
should not cause a call into the filesystems to reclaim memory because there are
already locks held that can potentially cause a deadlock. The “scoped
allocation” API is a better choice for filesystems to indicate that they
are holding a lock, so GFP_NOFS has long been on the chopping block, though
progress has been slow. In a filesystem-track session at
the 2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
, Matthew Wilcox wanted to
discuss how to move kernel filesystems away from the flag with the eventual
goal of removing it completely.

[$] Handling the NFS change attribute

Post Syndicated from jake original https://lwn.net/Articles/975863/

The saga of the i_version field for inodes, which tracks the
occurrence of changes
to the data or metadata of a file, continued in a discussion at the 2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
. In a session led by
Jeff Layton, who has been doing a lot the work on changing the semantics and functioning of
i_version
over the years, he updated attendees on the status of the effort since a session at last year’s summit. His summary
was that things are
“pretty much where we started last year”, but the discussion this time
pointed to some possible ways forward.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/976782/

Security updates have been issued by AlmaLinux (python39:3.9 and python39-devel:3.9 and ruby:3.0), Debian (chromium, gst-plugins-base1.0, and kernel), Fedora (chromium, glances, glycin-loaders, gnome-tour, helix, helvum, kitty, libarchive, libipuz, librsvg2, loupe, maturin, ntpd-rs, plasma-workspace, and a huge list of Rust-based packages due to a “mini-mass-rebuild” that updated the toolchain to Rust 1.78 and picked up fixes for various pieces), Mageia (gifsicle, netatalk, openssl, python-jinja2, and unbound), Red Hat (kernel and kernel-rt), SUSE (bind, glibc, gstreamer-plugins-base, squid, and tiff), and Ubuntu (glibc).

[$] New APIs for filesystems

Post Syndicated from jake original https://lwn.net/Articles/975444/

A discussion of extensions to the statx()
system call comes up frequently at the Linux Storage,
Filesystem, Memory Management, and BPF Summit
; this year’s edition was
no exception. Kent Overstreet led the first filesystem-only session at the
summit on querying information about filesystems that have subvolumes and
snapshots. While it was billed as a discussion on statx()
additions, it ranged more widely over new APIs needed for modern filesystems.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/976006/

Security updates have been issued by Debian (python-pymysql), Fedora (chromium, mingw-python-requests, and thunderbird), Mageia (perl-Email-MIME and qtnetworkauth5 & qtnetworkauth6), Red Hat (gdisk and python39:3.9 and python39-devel:3.9 modules), SUSE (freerdp, gdk-pixbuf, gifsicle, glib2, java-1_8_0-ibm, kernel, libfastjson, libredwg, nodejs16, python, python3, python36, rpm, warewulf4, and xdg-desktop-portal), and Ubuntu (gst-plugins-base1.0, python-werkzeug, and tpm2-tss).

[$] Filesystems and iomap

Post Syndicated from jake original https://lwn.net/Articles/974958/

The iomap
block-mapping abstraction is being used by more filesystems, in part
because of its support for large folios. But there are some challenges in
adopting iomap, which was the topic of a discussion led by Ritesh Harjani
in a combined storage and filesystem session at the 2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
. One of the main trouble
spots is how to handle metadata, which is not an area that iomap has been aimed
at.

Security updates for Monday

Post Syndicated from jake original https://lwn.net/Articles/975399/

Security updates have been issued by Debian (apache2, bluez, chromium, fossil, libreoffice, python-pymysql, redmine, and ruby-rack), Fedora (buildah, crosswords, dotnet7.0, glycin-loaders, gnome-tour, helix, helvum, libipuz, loupe, maturin, mingw-libxml2, ntpd-rs, perl-Email-MIME, and a huge list of Rust-based packages due to a “mini-mass-rebuild” that updated the toolchain to Rust 1.78 and picked up fixes for various pieces), Mageia (chromium-browser-stable, mariadb, and roundcubemail), Oracle (kernel, libreoffice, nodejs, and tomcat), and SUSE (cJSON, libfastjson, opera, postgresql15, python3, and qt6-networkauth).

[$] Atomic writes without tears

Post Syndicated from jake original https://lwn.net/Articles/974578/

John Garry and Ted Ts’o led a discussion about supporting atomic writes for buffered
I/O, without any torn (or partial) writes to the device, at the 2024 Linux Storage,
Filesystem, Memory Management, and BPF Summit
. It is something of a
continuation of a discussion at last year’s
summit
. The goal is to help PostgreSQL, which writes its data using
16KB buffered I/O; it currently has to do a lot of extra work to ensure
that its data is safe on disk. A promise of non-torn, 16KB buffered writes
would allow the database
to avoid doing double writes.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/974824/

Security updates have been issued by Debian (chromium), Fedora (chromium, libxml2, pgadmin4, and python-libgravatar), Mageia (ghostscript), Red Hat (389-ds:1.4, ansible-core, bind and dhcp, container-tools:rhel8, edk2, exempi, fence-agents, freeglut, frr, ghostscript, glibc, gmp, go-toolset:rhel8, grafana, grub2, gstreamer1-plugins-bad-free, gstreamer1-plugins-base, gstreamer1-plugins-good, harfbuzz, httpd:2.4, idm:DL1, idm:DL1 and idm:client modules, kernel, kernel-rt, krb5, LibRaw, libreoffice, libsndfile, libssh, libtiff, libX11, libxml2, libXpm, linux-firmware, motif, mutt, openssh, osbuild and osbuild-composer, pam, pcp, pcs, perl-Convert-ASN1, perl-CPAN, perl:5.32, pki-core:10.6 and pki-deps:10.6 modules, pmix, poppler, postgresql-jdbc, python-dns, python-jinja2, python-pillow, python27:2.7, python3.11, python3.11-cryptography, python3.11-urllib3, python39:3.9 and python39-devel:3.9 modules, qt5-qtbase, resource-agents, squashfs-tools, sssd, systemd, tigervnc, tomcat, traceroute, varnish:6, virt:rhel and virt-devel:rhel modules, vorbis-tools, webkit2gtk3, xorg-x11-server, xorg-x11-server-Xwayland, and zziplib), SUSE (chromium, perl, postgresql14, and python-sqlparse), and Ubuntu (klibc, linux-aws-hwe, openssl, and vlc).

[$] Supporting larger block sizes in filesystems

Post Syndicated from jake original https://lwn.net/Articles/974219/

In a
combined storage and filesystem session at the 2024
Linux Storage,
Filesystem, Memory Management, and BPF Summit
, Luis Chamberlain led a
discussion on filesystem support for block sizes larger than the usual 4KB
page size,
which followed up on discussion from last year. While the
session was meant to look at the intersection of larger block sizes
with atomic block writes that avoid torn
(partial) writes (which was also discussed last year), it mostly focused on the
filesystem side. Over time, the
block sizes offered by storage devices have risen from the original
512 bytes; Chamberlain
wanted to discuss filesystem support for block sizes larger than 4KB.

[$] Managing expectations with a contributions and credit policy

Post Syndicated from jake original https://lwn.net/Articles/971817/

Maintainers of open-source projects sometimes have disagreements with
contributors over how contributions are reviewed, modified, merged, and
credited. A written policy describing how contributions are handled can
help maintainers set reasonable expectations for potential contributors.
In turn, that can make the maintainer’s job easier because it can help
reduce a source of friction in the project. A guide to help create this
kind of policy for a project has recently been developed.

Security updates for Thursday

Post Syndicated from jake original https://lwn.net/Articles/973071/

Security updates have been issued by AlmaLinux (ansible-core, avahi, bind, buildah, containernetworking-plugins, edk2, fence-agents, file, freeglut, freerdp, frr, git-lfs, gnutls, golang, grafana, grafana-pcp, gstreamer1-plugins-bad-free, gstreamer1-plugins-base, gstreamer1-plugins-good, harfbuzz, httpd, ipa, libjpeg-turbo, libnbd, LibRaw, libreswan, libsndfile, libssh, libtiff, libvirt, libX11, libXpm, mingw components, mingw-glib2, mingw-pixman, mod_http2, mod_jk and mod_proxy_cluster, motif, mutt, openssl and openssl-fips-provider, osbuild-composer, pam, pcp, perl, pmix, podman, python-jinja2, python-jwcrypto, python3.11, python3.11-cryptography, python3.11-urllib3, qemu-kvm, qt5-qtbase, runc, skopeo, sssd, systemd, tcpdump, tigervnc, toolbox, webkit2gtk3, xorg-x11-server, xorg-x11-server-Xwayland, and zziplib), CentOS (firefox, grub2, kernel, squid, thunderbird, tigervnc, and xorg-x11-server), Debian (chromium, glib2.0, python-idna, webkit2gtk, and wordpress), Fedora (freerdp, freerdp2, and pypy), Mageia (chromium-browser-stable, exfatprogs, freeglut, libtiff, libvirt, libxml2, openpmix, php-tcpdf, ruby, tpm2-tools, tpm2-tss, traceroute, and zziplib), Oracle (bind, buildah, git-lfs, gnutls, golang, grafana, grafana-pcp, libreswan, libvirt, libxml2, mod_http2, podman, python-jwcrypto, skopeo, sssd, and tigervnc), Red Hat (nodejs:18, nodejs:20, and squid:4), and SUSE (avahi, ghostscript, go1.21, go1.22, python-pymongo, python-Werkzeug, and sssd).

[$] A proposal to switch Fedora Workstation’s desktop

Post Syndicated from jake original https://lwn.net/Articles/970929/

A proposal to switch the default desktop for Fedora Workstation from GNOME
to KDE Plasma largely went over like the proverbial lead balloon—unsurprisingly.
But the
conversation about the proposal did surface some areas where the
distribution could
perhaps be more inclusive with regard to the other desktop choices
available. The project believes that it
benefits from being opinionated and not requiring users to make
multiple decisions before they can even install the distribution, but there
is a balance
to be found.