All posts by corbet

Rust in Android: move fast and fix things (Google Security Blog)

Post Syndicated from corbet original https://lwn.net/Articles/1046397/

The Google Security Blog has a
new post
on just how well the use of Rust is working out for the
Android project.

We adopted Rust for its security and are seeing a 1000x reduction
in memory safety vulnerability density compared to Android’s C and
C++ code. But the biggest surprise was Rust’s impact on software
delivery. With Rust changes having a 4x lower rollback rate and
spending 25% less time in code review, the safer path is now also
the faster one.

Public-inbox 2.0.0 released

Post Syndicated from corbet original https://lwn.net/Articles/1045965/

Version 2.0.0 of public-inbox, the mail archiving system behind
lore.kernel.org and LWN’s email archive, has been released. “This
release includes several new features and fixes; mostly around improved
integration between inboxes and coderepos for solver. Portability and
reliability is also improved, especially in the internal process management
of lei.

A proposed kernel policy for LLM-generated contributions

Post Syndicated from corbet original https://lwn.net/Articles/1045806/

The kernel community is currently reviewing a
proposed policy
for contributors who are using large language models to
assist in the creation of their patches; the primary focus is on disclosure
of the use of those tools. “The goal here is to clarify community
expectations around tools. This lets everyone become more productive while
also maintaining high degrees of trust between submitters and
reviewers.

Freedesktop.org now hosts the Filesystem Hierarchy Standard

Post Syndicated from corbet original https://lwn.net/Articles/1045405/

The future of the Filesystem Hierarchy Standard (FHS) has been under discussion for some time; now,
Neal Gompa has announced
that the FHS is “hosted and stewarded” by Freedesktop.org.

For those who are unaware, the Filesystem Hierarchy Standard (FHS)
is the definition for POSIX operating systems to organize system
and user data. It is broadly adopted by Linux, BSD, and other
operating systems that follow POSIX-like conventions.

See this
page
for the specification’s new home.

[$] Toward fast, containerized, user-space filesystems

Post Syndicated from corbet original https://lwn.net/Articles/1044432/

Filesystems are complex and performance-sensitive beasts. They can also
present security concerns. Microkernel-based systems have long pushed
filesystems into separate processes in order to contain any vulnerabilities
that may be found there. Linux can do the same with the Filesystem in
Userspace
(FUSE) subsystem, but using FUSE brings a significant
performance penalty. Darrick Wong is working on ways to eliminate that
penalty, and he has a massive patch
set
showing how ext4 filesystems can be safely implemented in user space by
unprivileged processes with good performance. This work has the potential
to radically change how filesystems are managed on Linux systems.

[$] LWN.net Weekly Edition for November 6, 2025

Post Syndicated from corbet original https://lwn.net/Articles/1044227/

Inside this week’s LWN.net Weekly Edition:

  • Front: Python thread safety; Namespace reference counting; Merigraf; Speeding up short reads; Julia 1.12; systemd security.
  • Briefs: CHERIoT 1.0; Chromium XSLT; Arm KASLR; Bazzite; Devuan 6.0; Incus 6.18; LXQt 2.3.0; Rust 1.91.0; Quotes; …
  • Announcements: Newsletters, conferences, security updates, patches, and more.

Defeating KASLR by Doing Nothing at All (Project Zero)

Post Syndicated from corbet original https://lwn.net/Articles/1044867/

The Project Zero blog explains
that, on 64-bit Arm systems, the kernel’s direct map is always placed at
the same virtual location, regardless of whether kernel address-space
layout randomization (KASLR) is enabled.

While it remains true that KASLR should not be trusted to prevent
exploitation, particularly in local contexts, it is regrettable
that the attitude around Linux KASLR is so fatalistic that putting
in the engineering effort to preserve its remaining integrity is
not considered to be worthwhile. The joint effect of these two
issues dramatically simplified what might otherwise have been a
more complicated and likely less reliable exploit.

[$] Namespace reference counting and listns()

Post Syndicated from corbet original https://lwn.net/Articles/1043824/

The kernel’s namespaces feature is, among
other things, a key part of the implementation of containers. Like much in
the kernel, though, the namespace API evolved over time; there was no
design at the outset. As a result, this API has some rough edges and
missing features. Christian Brauner is working to straighten out the
namespace situation somewhat with this
daunting 72-part patch series
that, among other things, adds a new
system call to allow user space to query the namespaces present on the
system.

A new kernel port — to WebAssembly

Post Syndicated from corbet original https://lwn.net/Articles/1044786/

Joel Severin has announced
the availability of his port of the Linux kernel to WebAssembly; one can go
to this page and
watch it boot in a browser.

Wasm is similar to every other arch in Linux, but also
different. One important difference is that there is no way to
suspend execution of a task. There is a way around this though:
Linux supports up to 8k CPUs (or possibly more…). We can just
spin up a new CPU dedicated to each user task (process/thread) and
never preempt it

[$] The long path toward optimizing short reads

Post Syndicated from corbet original https://lwn.net/Articles/1043640/

The kernel’s file-I/O subsystems have been highly optimized over the years
in the hope of providing the best performance for a wide variety of
workloads. There is, however, one workload type that suffers with current
kernels: applications that perform many short reads, in multiple processes,
from the same file. Kiryl Shutsemau has been working on a patch to
try to optimize this case, but the task is turning out to be harder than
one might expect.

Python Software Foundation withdraws security-related grant proposal

Post Syndicated from corbet original https://lwn.net/Articles/1043563/

The Python Software Foundation, earlier this year, successfully obtained a
$1.5 million grant from the US National Science Foundation “to
address structural vulnerabilities in Python and PyPI
“. The actual
grant came with some strings attached though, in the form of a requirement
not to pursue diversity, equity, and inclusion programs. So the Foundation
has withdrawn
the proposal
rather than agree to terms that run counter to its own
mission.

We’re disappointed to have been put in the position where we had to
make this decision, because we believe our proposed project would
offer invaluable advances to the Python and greater open source
community, protecting millions of PyPI users from attempted
supply-chain attacks. The proposed project would create new tools
for automated proactive review of all packages uploaded to PyPI,
rather than the current process of reactive-only review.

Typst 0.14 released

Post Syndicated from corbet original https://lwn.net/Articles/1043242/

Version 0.14 of the
Typst document processor has been released.

If you need to comply with accessibility-related regulations, Typst
0.14 has your back. Typst now generates accessible documents by
default, with opt-in support for stricter checks. For those working
with complex illustrations, PDFs are now supported as a native
image format. In case you’re typesetting a book, the new
character-level justification will give your layout the final
touch. And if you’re building a website or blog, many improvements
to Typst’s HTML export are waiting for you.

LWN looked at Typst in September.

[$] Safer speculation-free user-space access

Post Syndicated from corbet original https://lwn.net/Articles/1042711/

The Spectre class of hardware vulnerabilities truly is a gift that keeps on
giving. New variants are still being discovered in current CPUs nearly
eight years after the disclosure of this
problem, and developers are still working to minimize the performance costs
that come from defending against it. The masked user-space access
mechanism is a case in point: it reduces the cost of defending against some
speculative attacks, but it brought some challenges of its own that are
only now being addressed.