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mwiegand 8971b23617
refactor(sandbox): collapse l4d2-sandbox user into left4me
The hardening refactor that just landed closes the same-uid attack
surface (FS view, ptrace, /proc visibility, signals) for the web +
gameserver units via systemd directives plus system-wide
kernel.yama.ptrace_scope=2. Keeping the script-sandbox on a separate
uid was the inconsistent half-step — defense-in-depth only, with
build-time-idmap complexity attached. One principle wins: harden
once, share the uid.

scripts/libexec/left4me-script-sandbox: drop the idmap block (uid
lookups, STAGING setup, cleanup_staging trap, mount --bind
--map-users), switch User=/Group= to left4me, point BindPaths at
\$OVERLAY_DIR directly. Header comment updated to reflect
hardening-not-uid as the same-uid defense. nsenter self-wrap kept —
it's about mount-namespace escape, not uid.

Tests + comments + companion docs updated. Build-time-idmap and
overlay-idmap plans marked SUPERSEDED; user-uid-split spec revised
to "1 user is correct"; one-line update notes on the hardening
specs and the build-overlay-unit-design.

Companion ckn-bw commit removes the l4d2-sandbox user + group and
tightens /var/lib/left4me from 0711 → 0755 (the traverse-only mode
was specifically for the sandbox uid).
2026-05-15 15:50:57 +02:00
deploy refactor(sandbox): collapse l4d2-sandbox user into left4me 2026-05-15 15:50:57 +02:00
docs refactor(sandbox): collapse l4d2-sandbox user into left4me 2026-05-15 15:50:57 +02:00
examples/script-overlays feat(l4d2-web): seed example script overlays from examples/script-overlays/ 2026-05-08 18:41:08 +02:00
l4d2host refactor(sandbox): collapse l4d2-sandbox user into left4me 2026-05-15 15:50:57 +02:00
l4d2web refactor(sandbox): collapse l4d2-sandbox user into left4me 2026-05-15 15:50:57 +02:00
scripts refactor(sandbox): collapse l4d2-sandbox user into left4me 2026-05-15 15:50:57 +02:00
.envrc chore: add direnv .envrc for local Python 3.13 venv 2026-05-08 18:56:51 +02:00
.gitignore chore: add dev.db and opencode.json to gitignore 2026-05-13 14:29:57 +02:00
AGENTS.md Revert "AGENTS: harden the spec+plan commit rule" 2026-05-11 22:26:47 +02:00
README.md chore: add direnv .envrc for local Python 3.13 venv 2026-05-08 18:56:51 +02:00

left4me

left4me is a local L4D2 server management platform with two planned components:

  1. l4d2host + l4d2ctl (host library + CLI)
  2. l4d2-web-app (Flask web app for users, blueprints, servers, jobs, and logs)

Status

Implementation plans remain the source of truth for architecture and task sequencing:

  • docs/superpowers/plans/2026-04-22-l4d2-host-lib-v1.md
  • docs/superpowers/plans/2026-04-23-l4d2-web-app-v1.md

Locked v1 Decisions

  • Naming is strictly l4d2 (not l4d).
  • Host library and web app are separate components.
  • Host CLI write commands are fixed to:
    • install
    • initialize <name> -f <spec.yaml>
    • start <name>
    • stop <name>
    • delete <name>
  • Host CLI read commands are available for the web/host boundary:
    • status <name> --json
    • logs <name> --lines <n> --follow/--no-follow
  • The web app calls host operations through l4d2ctl, not direct l4d2host imports.
  • Deployment uses /var/lib/left4me for runtime state, /opt/left4me for repository contents and the virtualenv, /etc/left4me for environment files, and global units under /usr/local/lib/systemd/system.
  • Overlay handling is directory-based; the web app populates each overlay (workshop downloads, managed-global refresh).
  • No lock manager, no rollback, no preflight checks in host library.
  • CLI propagates subprocess failures via stderr and return code.
  • delete on missing instance is no-op success.
  • Blueprint model (web app):
    • user-private in v1
    • servers are live-linked to blueprint
    • no per-server overrides
    • delete blueprint blocked when linked servers exist
    • blueprint changes apply on next action
    • server can reassign blueprint anytime

Planned Repository Layout

  • l4d2host/
  • l4d2web/
  • deploy/
  • docs/superpowers/plans/

Deployment

See deploy/README.md for the Linux test deployment contract, including the runtime user, target filesystem layout, systemd units, privileged helpers, sudoers rules, admin bootstrap, and overlay reference rules.

Local development

This repo uses direnv to auto-activate a Python 3.13 venv on cd (matching the Debian Trixie production target). With direnv installed and hooked into your shell:

  1. direnv allow once per fresh checkout (and after any .envrc change).
  2. cd out and back in — .direnv/python-3.13/ is created and put on PATH.
  3. pip install -e ./l4d2host -e ./l4d2web to install both packages editable.
  4. pip install pytest to run the test suites (pytest tests/ inside either subproject).

Tech Stack (planned)

  • Python 3.12+
  • Typer, PyYAML, pytest
  • Flask, SQLAlchemy, Alembic
  • HTMX (vendored locally), custom CSS, SSE
  • systemd units, kernel overlayfs (mounted via the left4me-overlay privileged helper), steamcmd
  1. Implement l4d2host plan first.
  2. Implement l4d2web plan second.
  3. Keep tests green task-by-task (TDD flow from plans).
  4. Keep commits small and aligned with plan tasks.

Contributing Notes

  • Follow plan task order unless explicitly re-planned.
  • Keep contracts above unchanged unless the user asks to change them.
  • Update plan docs when scope or behavior changes.