Package: apt Version: 3.3.4 Severity: wishlist Hello,
I would like to work on re-enabling APT's seccomp sandbox for the acquire methods by default, and would like to know whether the team would welcome that before I start. Background, as I understand it: - The sandbox was added in 2017 (32bcbd73e) and turned off by default in 1.6~rc1 (e688a4f48), closing LP: #1732030, #890489 and linuxdeploy#869. - The reported breakages were mostly allow-list gaps (getdents through NSS modules such as libnss-libvirt, socket/connect in store, pread64 on NFS/NIS), plus the x32 issue and environments where the policy cannot load. - The allow-list is still maintained: da74672bc (2025, #1091351) allowed directory reading in http for OpenSSL. Evidence that it works on common setups: - Wikimedia's puppet apt module sets APT::Sandbox::Seccomp "true" (operations-puppet, modules/apt/manifests/init.pp); I found no Allow/Trap entries anywhere in that repository. - Kicksecure has shipped the same setting since 2019 (security-misc, etc/apt/apt.conf.d/40sandbox). - On a current debian:sid arm64 container (2026-10-27), apt-get update and install --download-only hello work with it enabled, with no seccomp warnings. Still open: - #882588 (proxychains) and #888993 (fakeroot): LD_PRELOAD tools that inject syscalls a fixed allow-list cannot predict. - #951718: seccomp overrides by syscall number. A rough plan, one merge request per step: 1. Skip the sandbox with a notice when an LD_PRELOAD wrapper is detected, the same way it is already skipped under qemu-user (243acdee1). 2. Close the remaining known allow-list gaps and add overrides b number (#951718). 3. Flip the default in unstable early in a release cycle, with a NEWS entry and APT::Sandbox::Seccomp "false" as the way out. Questions: - Would you accept a default-on change if the above is done? - What else, beyond the bugs above, made you turn it off in 2018 that I should account for? - Would you rather see Landlock for file access on top of seccom pacman's downloader sandbox uses both. I can test on arm64 (Docker) and on an Ubuntu 24.04 amd64 server. Thanks, Marc
