Sandlock 0.8.9 tightens Linux process sandbox boundaries
Process-level sandboxing is attractive for agent and build workloads, but the release notes show how much correctness depends on filesystem, network-view, and process-lifecycle edge cases.
Logged at IST: 2026-10-05 14:38 IST
What it is: Sandlock is a Rust/Linux process sandbox built with Landlock and seccomp, intended to run without root, cgroups, or namespaces.
Gist: Version 0.8.9 fixes a filesystem-confinement path involving copy-on-write opens and absolute symlinks, virtualizes /proc network tables for sandbox-owned sockets, improves cleanup of descendant process groups, and adds composable network allow/deny rules. The release also changes the checkpoint image format: version 2 images are no longer accepted.
Why it matters: Process sandboxes can be lighter than containers or VMs, but the security boundary lives in details such as symlink resolution, process descendants, and what a sandbox can observe about networking. This release is a useful reminder to evaluate the exact confinement model rather than treating “sandbox” as a binary assurance.
Caveat: These are release-note claims, not an independent security audit.