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 Build-time-idmap and overlay-idmap plans marked SUPERSEDED; user-uid-split spec revised to "1 user is correct"; one-line update notes on the hardening specs and the build-overlay-unit-design.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). |
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|---|---|---|
| .. | ||
| alembic | ||
| routes | ||
| services | ||
| static | ||
| templates | ||
| tests | ||
| __init__.py | ||
| alembic.ini | ||
| app.py | ||
| auth.py | ||
| cli.py | ||
| config.py | ||
| db.py | ||
| models.py | ||
| pyproject.toml | ||
| README.md | ||
l4d2-web-app
Flask web app for managing L4D2 servers through user-private blueprints.
Key v1 behaviors
- Local username/password login; no public signup
- Admin-managed overlay catalog
- Private blueprints per user
- Server creation from blueprints (live-linked; no per-server blueprint overrides)
- Async job model with persisted command logs in
job_logs - Desired vs actual state model
- Live logs for jobs and servers via SSE endpoints
- Host operations go through
l4d2ctlvia a local host command runner, not directl4d2hostimports
Frontend constraints
- Server-rendered templates (Jinja)
- Vendored HTMX (
static/vendor/htmx.min.js) - Custom CSS only
- Tokenized, consistent link and accent colors
Development
python3 -m venv .venv
.venv/bin/pip install -e .
.venv/bin/pytest tests -q
Configuration
The web app reads these settings from the environment:
DATABASE_URL: SQLAlchemy database URL, for examplesqlite:////var/lib/left4me/left4me.db.SECRET_KEY: Flask secret key used for sessions and CSRF-sensitive state.JOB_WORKER_THREADS: number of background job worker threads.
In the systemd deployment, environment is loaded from /etc/left4me/host.env and /etc/left4me/web.env.
Admin Bootstrap
Create the first admin account with the Flask CLI. Provide the password through LEFT4ME_ADMIN_PASSWORD:
LEFT4ME_ADMIN_PASSWORD='change-me' flask create-user <username> --admin