111 lines
4.0 KiB
Markdown
111 lines
4.0 KiB
Markdown
---
|
|
project: env-file-hardening
|
|
type: project-plan
|
|
status: active
|
|
path: Tech/Projects
|
|
tags:
|
|
- pbs
|
|
- security
|
|
- docker
|
|
- ansible
|
|
- secrets
|
|
created: 2026-04-19
|
|
updated: 2026-04-19
|
|
---
|
|
|
|
# Env File Hardening (Sidecar Pattern)
|
|
|
|
## Goal
|
|
|
|
Remove the easy path to PBS secrets. Right now `.env` files in
|
|
`/opt/docker` are readable by anyone with filesystem access — including
|
|
`pbsdeploy`. If the deploy key is compromised, an attacker can `cat .env`
|
|
and grab every API key and password instantly.
|
|
|
|
Goal: `pbsdeploy` can deploy containers without ever being able to read the
|
|
secrets they use.
|
|
|
|
## Threat Model
|
|
|
|
- **Primary risk:** `pbsdeploy` SSH key leaks → attacker SSHes in → reads
|
|
`.env` files → owns every service.
|
|
- **Mitigation goal:** eliminate the trivial read path. Raise the bar so an
|
|
attacker would need to escalate to root (no sudo on `pbsdeploy`), pivot
|
|
accounts, or break out of a container.
|
|
- **Accepted residual risk:** Determined attackers with deep access can
|
|
still cause damage. This is about removing low-hanging fruit, not achieving
|
|
zero risk.
|
|
|
|
## Architecture
|
|
|
|
**Sidecar injection pattern:**
|
|
|
|
- `.env` files stay owned by `root:root` with `600` perms.
|
|
- Ansible writes them via `become: yes` (sudo) — `pbsdeploy` never touches
|
|
the files directly.
|
|
- A tiny init container / sidecar runs as root, reads the locked `.env`,
|
|
and injects secrets into the main container as environment variables.
|
|
- Main containers read env vars exactly as they do today — **no application
|
|
code changes.**
|
|
|
|
## Design Decisions
|
|
|
|
- **Sidecar over Docker Compose secrets** — Compose secrets would require
|
|
refactoring every app (WordPress, n8n, pbs-hub, PBSII layers) to read from
|
|
`/run/secrets/` files instead of env vars. Sidecar gets the security win
|
|
with zero app-level changes.
|
|
- **Sidecar over external secret manager (Vault, etc.)** — overkill for
|
|
homelab/small prod scale. Revisit if we ever move to Kubernetes.
|
|
- **Ansible stays the deploy tool** — still writes `.env` files, just as
|
|
root with tight perms. `pbsdeploy` has no sudo entry, so it can't read them
|
|
back.
|
|
- **Scope: all services on production PBS** — WordPress, n8n, pbs-hub,
|
|
phpMyAdmin, everything in `/opt/docker`. No point hardening one service if
|
|
others still leak.
|
|
- **Staging first** — test on one service on staging, then roll out across
|
|
all services on staging, then move to production.
|
|
|
|
## How the Permissions Work
|
|
|
|
- Ansible SSHes in as `pbsdeploy` → uses `become: yes` to elevate for file
|
|
writes → files created as `root:root 600`.
|
|
- `pbsdeploy` can't `cat` them (no read perms). Can't `sudo cat` them
|
|
either (no sudoers entry).
|
|
- Docker daemon runs as root → sidecar container runs as root → can read
|
|
the files and inject into main container.
|
|
- Main container sees env vars, doesn't know or care where they came from.
|
|
|
|
## Next Steps
|
|
|
|
- [ ] Pick a non-critical service on staging to pilot the sidecar pattern
|
|
- [ ] Design the sidecar container (shell script? tiny Go/Python binary?
|
|
off-the-shelf image?)
|
|
- [ ] Update compose file for pilot service to include sidecar
|
|
- [ ] Update Ansible role to write `.env` as `root:root 600` (not
|
|
`deployer` group)
|
|
- [ ] Test on staging — verify containers still work, verify `pbsdeploy`
|
|
can't read files
|
|
- [ ] Roll out to all staging services
|
|
- [ ] Verify nothing broke in staging over a few deploys
|
|
- [ ] Roll out to production
|
|
- [ ] Remove `deployer` group's access to `.env` files (or the group
|
|
entirely, depending on what it ends up being used for)
|
|
|
|
## Open Questions
|
|
|
|
- What's the right sidecar implementation? Custom shell-based init
|
|
container vs. existing tool?
|
|
- Which pilot service to start with?
|
|
- Does anything else in `/opt/docker` currently rely on the `deployer`
|
|
group having read access that we'd break by tightening perms?
|
|
|
|
## Depends On / Related
|
|
|
|
- **SSH Login Alerting** — higher priority sibling project. Even before env
|
|
hardening is done, SSH alerts give us early warning if `pbsdeploy` is
|
|
compromised.
|
|
- **PBSII CI/CD** — same `pbsdeploy` / `deployer` setup on staging;
|
|
whatever we do here applies there too.
|
|
|
|
|
|
...sent from Jenny & Travis |