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7 changed files with 657 additions and 2 deletions
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@ -169,7 +169,7 @@ Single-contributor, trunk-based (no merge requests / approval gates):
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- Edit vault-encrypted files directly — decrypt first, re-encrypt after
|
||||
- Force-push or rewrite already-pushed history on `main`
|
||||
- Add a collection to `requirements.yml` without a specific module need in existing role tasks
|
||||
- Open a firewall port anywhere but the `group_vars` firewall definitions — never ad-hoc on a host (ADR-002)
|
||||
- Open a firewall port anywhere but the `group_vars` service catalog — never ad-hoc on a host. If it's not in the catalog, it doesn't exist (ADR-002, ADR-020)
|
||||
- Disable or weaken a baseline control from ADR-002 (SSH hardening, nftables default-deny, fail2ban, auditd)
|
||||
- Expose a service to the LAN/WAN without it sitting behind the reverse proxy with authentication (ADR-002)
|
||||
- Deploy a service that hasn't cleared `docs/security/service-checklist.md` (record any deviation in `docs/security/accepted-risks.md`)
|
||||
|
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@ -223,6 +223,7 @@ Single-contributor, trunk-based (no merge requests / approval gates):
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|||
| Hardware & capacity | `docs/decisions/012-hardware-capacity.md` |
|
||||
| Logging & log integrity | `docs/decisions/018-logging.md` |
|
||||
| Tagging & run-targeting | `docs/decisions/019-tagging.md` |
|
||||
| Firewall strategy | `docs/decisions/020-firewall.md` |
|
||||
| Adding a new role | `docs/runbooks/new-role.md` |
|
||||
| Adding a new host | `docs/runbooks/new-host.md` |
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||||
| Rotating vault secrets | `docs/runbooks/rotate-secrets.md` |
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||||
|
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@ -31,6 +31,10 @@ decisions this frame enables.
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|||
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_(DHCP, firewall, mDNS reflection live on OPNsense — Ansible-managed, not containers.)_
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||||
_Firewalling is two-layer (ADR-020): OPNsense at the perimeter + inter-VLAN, plus
|
||||
per-host `nftables` (default-deny inbound + east-west allowlist) rendered by the `base`
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role from a shared `group_vars` service catalog. Both layers are still to be built._
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## 2. Identity & access — [P]
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||||
| Capability | Candidate service(s) | Tier | Commitment | What it does | Notes / open |
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|
|
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@ -77,3 +77,20 @@ earning its keep.
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ADR's Deferred list** in the same change. Three hits now — promote from "worth a
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||||
check" to **build it**: a `/review-repo` rule flagging any ADR "Deferred/Open" entry
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||||
whose subject is named as RESOLVED/DECIDED elsewhere.
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|
||||
## 2026-06-06
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||||
- `[recurring]` **Asked the execution-mode question AGAIN** ("subagent-driven vs inline —
|
||||
which approach?") at the end of `writing-plans`, despite the 2026-06-05 standing
|
||||
preference *and* the `always-subagent-driven-execution` memory both saying don't ask.
|
||||
Root cause: the `writing-plans` skill's "Execution Handoff" step scripts the menu, and
|
||||
I followed the skill text over the user's standing override. Second occurrence →
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||||
escalate from "skip the prompt" to a **hard rule**: never present the execution-mode
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||||
menu; finishing a plan means defaulting straight to subagent-driven.
|
||||
- `[friction]` **Don't pause for approval between writing a plan and implementing it.**
|
||||
The user has standing pre-approval to carry straight through plan → implementation. The
|
||||
brainstorming/plan flow already has explicit approval gates (design approval, spec
|
||||
review); adding another "shall I proceed to implement?" gate after the plan is written
|
||||
is redundant friction. → After `writing-plans` finishes, begin subagent-driven
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||||
implementation directly. The only reason to stop is a genuine blocker or ambiguity, not
|
||||
a routine checkpoint.
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||||
|
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@ -23,7 +23,12 @@
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translate-don't-transplant — V4 is a source only of gotchas + working config
|
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snippets, re-derived on boma's terms; never structure/requirements/values.
|
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4. Decide what each node runs — base packages plus which apps/services.
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5. Decide the firewall strategy (which firewall, ruleset, per-host vs central).
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5. ~~Decide the firewall strategy (which firewall, ruleset, per-host vs central).~~
|
||||
DECIDED (ADR-020): two layers — OPNsense (perimeter + inter-VLAN) + host nftables
|
||||
(default-deny inbound + east-west allowlist, permissive egress). Single source of
|
||||
truth: a `group_vars` service catalog with symbolic sources; each layer renders
|
||||
its own slice. Builds deferred to follow-up specs (host nftables in `base`, then
|
||||
OPNsense-as-code).
|
||||
6. Wire up the monitoring stack. Logging topology DECIDED (ADR-018): cluster Loki
|
||||
(all logs) + off-site security subset on `askari` + Grafana on-cluster (not the
|
||||
whole stack on `askari`). Still to design/build: Prometheus + metric exporters,
|
||||
|
|
|
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133
docs/decisions/020-firewall.md
Normal file
133
docs/decisions/020-firewall.md
Normal file
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@ -0,0 +1,133 @@
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|||
# ADR-020 — Firewall strategy: two-layer model with a shared service catalog
|
||||
|
||||
## Status
|
||||
|
||||
Accepted (2026-06-06). Resolves TODO 3.5 ("Decide the firewall strategy — which
|
||||
firewall, ruleset, per-host vs central").
|
||||
|
||||
**Strategy ADR.** It pins the architecture and each layer's responsibilities; the
|
||||
detailed builds are separate follow-up efforts (see *Scope*).
|
||||
|
||||
## Context
|
||||
|
||||
boma needs a firewall strategy that is predictable, declarative, and defends the stated
|
||||
threat model — opportunistic external, lateral movement / blast radius, operator/agent
|
||||
error (ADR-002). The pieces were already committed across other ADRs (`nftables`
|
||||
default-deny on hosts — ADR-002; OPNsense at the perimeter — ADR-007; Docker with
|
||||
`iptables: false` — ADR-004), but nothing tied them together: which layer owns what,
|
||||
where firewall intent is declared, and how the layers stay consistent. Without that,
|
||||
ports drift open ad-hoc and "per-host vs central" stays unanswered.
|
||||
|
||||
## Decision
|
||||
|
||||
### Two layers, distinct jobs
|
||||
|
||||
**OPNsense — perimeter + inter-VLAN.** Owns the WAN edge and all policy *between zones*:
|
||||
`lan`/`iot`/`guest` → `srv`, `mgmt` access, and the per-VLAN egress rules (ADR-007). It
|
||||
is **structurally blind to intra-`srv` traffic** — services share the switched `srv`
|
||||
subnet (VLAN 20), which never reaches the gateway.
|
||||
|
||||
**Host nftables — host-local + east-west within `srv`** (in the `base` role, every VM):
|
||||
|
||||
- **Default-deny inbound**; allow loopback + established/related.
|
||||
- **East-west allowlist**: a service host accepts a connection only from declared
|
||||
sources (e.g. the reverse proxy, a named peer) — the lateral-movement control OPNsense
|
||||
cannot provide.
|
||||
- **Permissive egress**: allow outbound + established/related; per-VLAN egress
|
||||
restriction stays at OPNsense (ADR-007). Host-level egress allowlisting is
|
||||
high-friction (every DNS/NTP/update/registry/webhook must be enumerated) for limited
|
||||
added benefit once the VLAN already bounds where a host can go.
|
||||
- **Docker**: daemon runs with `"iptables": false`; nftables owns all filtering,
|
||||
including container traffic (ADR-004).
|
||||
- **Guaranteed management plane**: loopback, established/related, and `wt0` (NetBird,
|
||||
ADR-016) for SSH + Ansible are always allowed, independent of the catalog, applied
|
||||
atomically — a malformed or empty catalog can never lock out management. (ADR-016: SSH
|
||||
is allowed only on `wt0`.)
|
||||
|
||||
So "per-host vs central" is answered: **both**, with clear ownership.
|
||||
|
||||
### Single source of truth — a shared service catalog
|
||||
|
||||
A central, declarative **service catalog** in `group_vars/` is the one source of truth
|
||||
for firewall intent (aligning with ADR-002's "port definitions live in `group_vars/`",
|
||||
and keeping connectivity *topology* in inventory rather than in any one self-contained
|
||||
service role — ADR-004). Each entry describes a service's **ingress**:
|
||||
|
||||
```yaml
|
||||
photoprism:
|
||||
ingress:
|
||||
- { from: reverse_proxy, port: 2342, proto: tcp }
|
||||
reverse_proxy:
|
||||
ingress:
|
||||
- { from: lan, port: 443, proto: tcp }
|
||||
```
|
||||
|
||||
`from` is **symbolic**, resolved at render time: a host/group → IP(s) from inventory; a
|
||||
role (`reverse_proxy`) → the host(s) filling it; a VLAN/zone (`lan`) → the subnet from
|
||||
the ADR-007 table. This keeps the catalog readable and resilient to IP changes.
|
||||
|
||||
### Each layer renders only its own slice
|
||||
|
||||
| Ingress rule | Host nftables | OPNsense |
|
||||
|---|---|---|
|
||||
| `from: reverse_proxy` (a `srv` peer) | allow proxy IP → port | — (intra-`srv`, invisible) |
|
||||
| `from: lan` (cross-VLAN) | allow `lan` subnet → port | allow `lan` → host:port |
|
||||
|
||||
The dominant pattern falls out naturally: most services are **proxied** — their only
|
||||
ingress is `from: reverse_proxy`, and users reach them through the reverse proxy, which
|
||||
alone carries `from: lan, port: 443` (matches "services sit behind the reverse proxy
|
||||
with authentication", ADR-002).
|
||||
|
||||
This was chosen over a single connectivity-model-generates-both (too much machinery,
|
||||
tight coupling of two very different rule domains) and over fully independent per-layer
|
||||
declarations (real drift risk).
|
||||
|
||||
### OPNsense automation — owned here, mechanism deferred
|
||||
|
||||
OPNsense is Ansible-managed (CLAUDE.md: "OPNsense is entirely Ansible; no Terraform
|
||||
OPNsense provider"). It renders the cross-VLAN slice of the catalog plus the static
|
||||
ADR-007 facts. The **how** — config-XML templating vs the OPNsense API vs a plugin — is
|
||||
deferred to the OPNsense-as-code follow-up spec. Recorded as an explicit open
|
||||
sub-decision.
|
||||
|
||||
## Guardrails
|
||||
|
||||
- **The catalog is authoritative.** If a port is not in the catalog, it does not exist —
|
||||
hardening the existing rule "never open a firewall port ad-hoc on a host" (ADR-002).
|
||||
- **The `firewall` tag** (ADR-019) marks firewall tasks; `--tags firewall` re-renders
|
||||
rules.
|
||||
- **Drift detection (aspiration).** A deterministic check — in the spirit of
|
||||
`scripts/check-tags.py` — comparing each host's live `nft` ruleset / listening ports
|
||||
against the catalog and flagging anything undeclared. Ties to TODO 8.5
|
||||
(`/security-review`). Not necessarily built first.
|
||||
|
||||
## Consequences
|
||||
|
||||
- Lateral movement within `srv` is constrained — the gap OPNsense structurally can't
|
||||
close.
|
||||
- One declarative catalog → no ad-hoc ports and no cross-layer drift on shared facts
|
||||
(ports, IPs, sources).
|
||||
- Cost: the catalog + render-per-layer machinery must be built and maintained; east-west
|
||||
allowlisting adds per-service ingress declarations (mitigated by proxied-by-default,
|
||||
which keeps most entries to a single line).
|
||||
|
||||
## Scope
|
||||
|
||||
**Decided here:** the two-layer model and responsibilities; host nftables = default-deny
|
||||
inbound + east-west allowlist + permissive egress + guaranteed management plane + Docker
|
||||
`iptables:false`; the shared `group_vars` catalog as single source of truth with
|
||||
symbolic sources; each layer renders its own slice; the no-ad-hoc-ports guardrail.
|
||||
|
||||
**Deferred to follow-up specs (each its own brainstorm → plan):**
|
||||
|
||||
1. **Host nftables implementation** in `base` — catalog schema, nftables template,
|
||||
Docker `iptables:false` integration, fail-safe ordering, Molecule tests. The natural
|
||||
next spec.
|
||||
2. **OPNsense-as-code** — tooling mechanism + cross-VLAN rule rendering.
|
||||
3. **Drift-detection check** — if/when built.
|
||||
|
||||
## Related
|
||||
|
||||
ADR-002 (security baseline: nftables default-deny, fail2ban, blast radius),
|
||||
ADR-004 (Docker model: `iptables:false`), ADR-007 (network topology, VLANs, OPNsense,
|
||||
per-VLAN egress), ADR-016 (NetBird mesh: SSH on `wt0` only), ADR-019 (`firewall` tag).
|
||||
331
docs/superpowers/plans/2026-06-06-firewall-strategy.md
Normal file
331
docs/superpowers/plans/2026-06-06-firewall-strategy.md
Normal file
|
|
@ -0,0 +1,331 @@
|
|||
# Firewall Strategy (ADR-020) Implementation Plan
|
||||
|
||||
> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
|
||||
|
||||
**Goal:** Land the firewall *strategy* as ADR-020 and fold it into the living docs — no firewall code is built here (the host-nftables and OPNsense-as-code builds are separate follow-up specs).
|
||||
|
||||
**Architecture:** This is a documentation-only change. It creates `docs/decisions/020-firewall.md` from the approved design spec, then updates CLAUDE.md (Further reading + the firewall guardrail), `docs/TODO.md` (mark 3.5 decided), and `docs/CAPABILITIES.md` (point the firewall note at ADR-020). There is no executable code, so verification is consistency greps + `make lint`.
|
||||
|
||||
**Tech Stack:** Markdown docs only. `make lint` (yamllint + ansible-lint + check-tags) must stay green; none of these tools lint Markdown content, but the run confirms nothing else broke.
|
||||
|
||||
---
|
||||
|
||||
## File structure
|
||||
|
||||
| File | Responsibility | Action |
|
||||
|------|----------------|--------|
|
||||
| `docs/decisions/020-firewall.md` | The firewall strategy ADR (two-layer model, shared catalog, deferred builds) | Create |
|
||||
| `CLAUDE.md` | Add ADR-020 to *Further reading*; harden the firewall guardrail bullet to reference the catalog/ADR-020 | Modify |
|
||||
| `docs/TODO.md` | Mark item 3.5 DECIDED (ADR-020) | Modify |
|
||||
| `docs/CAPABILITIES.md` | Point the existing firewall parenthetical at ADR-020 + the two-layer model | Modify |
|
||||
|
||||
Notes for the implementer:
|
||||
- The design spec this ADR is based on is `docs/superpowers/specs/2026-06-06-firewall-strategy-design.md` — read it if you need the full rationale, but the ADR text below is complete and self-contained.
|
||||
- Existing ADRs live in `docs/decisions/` numbered 001–019; this is 020. Match their concise, decision-focused tone (ADR-019 is a good recent reference).
|
||||
- Before any `git commit`, the pre-commit hook runs and decrypts `vault.yml`, so the vault agent must be unlocked: run `rbw unlocked` (exit 0 = good). If locked, ask the user to `rbw unlock` and wait. None of these tasks touch vault files.
|
||||
- Run `make lint` via the repo venv wiring (the Makefile handles paths).
|
||||
|
||||
---
|
||||
|
||||
### Task 1: Write ADR-020
|
||||
|
||||
**Files:**
|
||||
- Create: `docs/decisions/020-firewall.md`
|
||||
|
||||
- [ ] **Step 1: Create the ADR**
|
||||
|
||||
Create `docs/decisions/020-firewall.md` with exactly this content:
|
||||
|
||||
````markdown
|
||||
# ADR-020 — Firewall strategy: two-layer model with a shared service catalog
|
||||
|
||||
## Status
|
||||
|
||||
Accepted (2026-06-06). Resolves TODO 3.5 ("Decide the firewall strategy — which
|
||||
firewall, ruleset, per-host vs central").
|
||||
|
||||
**Strategy ADR.** It pins the architecture and each layer's responsibilities; the
|
||||
detailed builds are separate follow-up efforts (see *Scope*).
|
||||
|
||||
## Context
|
||||
|
||||
boma needs a firewall strategy that is predictable, declarative, and defends the stated
|
||||
threat model — opportunistic external, lateral movement / blast radius, operator/agent
|
||||
error (ADR-002). The pieces were already committed across other ADRs (`nftables`
|
||||
default-deny on hosts — ADR-002; OPNsense at the perimeter — ADR-007; Docker with
|
||||
`iptables: false` — ADR-004), but nothing tied them together: which layer owns what,
|
||||
where firewall intent is declared, and how the layers stay consistent. Without that,
|
||||
ports drift open ad-hoc and "per-host vs central" stays unanswered.
|
||||
|
||||
## Decision
|
||||
|
||||
### Two layers, distinct jobs
|
||||
|
||||
**OPNsense — perimeter + inter-VLAN.** Owns the WAN edge and all policy *between zones*:
|
||||
`lan`/`iot`/`guest` → `srv`, `mgmt` access, and the per-VLAN egress rules (ADR-007). It
|
||||
is **structurally blind to intra-`srv` traffic** — services share the switched `srv`
|
||||
subnet (VLAN 20), which never reaches the gateway.
|
||||
|
||||
**Host nftables — host-local + east-west within `srv`** (in the `base` role, every VM):
|
||||
|
||||
- **Default-deny inbound**; allow loopback + established/related.
|
||||
- **East-west allowlist**: a service host accepts a connection only from declared
|
||||
sources (e.g. the reverse proxy, a named peer) — the lateral-movement control OPNsense
|
||||
cannot provide.
|
||||
- **Permissive egress**: allow outbound + established/related; per-VLAN egress
|
||||
restriction stays at OPNsense (ADR-007). Host-level egress allowlisting is
|
||||
high-friction (every DNS/NTP/update/registry/webhook must be enumerated) for limited
|
||||
added benefit once the VLAN already bounds where a host can go.
|
||||
- **Docker**: daemon runs with `"iptables": false`; nftables owns all filtering,
|
||||
including container traffic (ADR-004).
|
||||
- **Guaranteed management plane**: loopback, established/related, and `wt0` (NetBird,
|
||||
ADR-016) for SSH + Ansible are always allowed, independent of the catalog, applied
|
||||
atomically — a malformed or empty catalog can never lock out management. (ADR-016: SSH
|
||||
is allowed only on `wt0`.)
|
||||
|
||||
So "per-host vs central" is answered: **both**, with clear ownership.
|
||||
|
||||
### Single source of truth — a shared service catalog
|
||||
|
||||
A central, declarative **service catalog** in `group_vars/` is the one source of truth
|
||||
for firewall intent (aligning with ADR-002's "port definitions live in `group_vars/`",
|
||||
and keeping connectivity *topology* in inventory rather than in any one self-contained
|
||||
service role — ADR-004). Each entry describes a service's **ingress**:
|
||||
|
||||
```yaml
|
||||
photoprism:
|
||||
ingress:
|
||||
- { from: reverse_proxy, port: 2342, proto: tcp }
|
||||
reverse_proxy:
|
||||
ingress:
|
||||
- { from: lan, port: 443, proto: tcp }
|
||||
```
|
||||
|
||||
`from` is **symbolic**, resolved at render time: a host/group → IP(s) from inventory; a
|
||||
role (`reverse_proxy`) → the host(s) filling it; a VLAN/zone (`lan`) → the subnet from
|
||||
the ADR-007 table. This keeps the catalog readable and resilient to IP changes.
|
||||
|
||||
### Each layer renders only its own slice
|
||||
|
||||
| Ingress rule | Host nftables | OPNsense |
|
||||
|---|---|---|
|
||||
| `from: reverse_proxy` (a `srv` peer) | allow proxy IP → port | — (intra-`srv`, invisible) |
|
||||
| `from: lan` (cross-VLAN) | allow `lan` subnet → port | allow `lan` → host:port |
|
||||
|
||||
The dominant pattern falls out naturally: most services are **proxied** — their only
|
||||
ingress is `from: reverse_proxy`, and users reach them through the reverse proxy, which
|
||||
alone carries `from: lan, port: 443` (matches "services sit behind the reverse proxy
|
||||
with authentication", ADR-002).
|
||||
|
||||
This was chosen over a single connectivity-model-generates-both (too much machinery,
|
||||
tight coupling of two very different rule domains) and over fully independent per-layer
|
||||
declarations (real drift risk).
|
||||
|
||||
### OPNsense automation — owned here, mechanism deferred
|
||||
|
||||
OPNsense is Ansible-managed (CLAUDE.md: "OPNsense is entirely Ansible; no Terraform
|
||||
OPNsense provider"). It renders the cross-VLAN slice of the catalog plus the static
|
||||
ADR-007 facts. The **how** — config-XML templating vs the OPNsense API vs a plugin — is
|
||||
deferred to the OPNsense-as-code follow-up spec. Recorded as an explicit open
|
||||
sub-decision.
|
||||
|
||||
## Guardrails
|
||||
|
||||
- **The catalog is authoritative.** If a port is not in the catalog, it does not exist —
|
||||
hardening the existing rule "never open a firewall port ad-hoc on a host" (ADR-002).
|
||||
- **The `firewall` tag** (ADR-019) marks firewall tasks; `--tags firewall` re-renders
|
||||
rules.
|
||||
- **Drift detection (aspiration).** A deterministic check — in the spirit of
|
||||
`scripts/check-tags.py` — comparing each host's live `nft` ruleset / listening ports
|
||||
against the catalog and flagging anything undeclared. Ties to TODO 8.5
|
||||
(`/security-review`). Not necessarily built first.
|
||||
|
||||
## Consequences
|
||||
|
||||
- Lateral movement within `srv` is constrained — the gap OPNsense structurally can't
|
||||
close.
|
||||
- One declarative catalog → no ad-hoc ports and no cross-layer drift on shared facts
|
||||
(ports, IPs, sources).
|
||||
- Cost: the catalog + render-per-layer machinery must be built and maintained; east-west
|
||||
allowlisting adds per-service ingress declarations (mitigated by proxied-by-default,
|
||||
which keeps most entries to a single line).
|
||||
|
||||
## Scope
|
||||
|
||||
**Decided here:** the two-layer model and responsibilities; host nftables = default-deny
|
||||
inbound + east-west allowlist + permissive egress + guaranteed management plane + Docker
|
||||
`iptables:false`; the shared `group_vars` catalog as single source of truth with
|
||||
symbolic sources; each layer renders its own slice; the no-ad-hoc-ports guardrail.
|
||||
|
||||
**Deferred to follow-up specs (each its own brainstorm → plan):**
|
||||
|
||||
1. **Host nftables implementation** in `base` — catalog schema, nftables template,
|
||||
Docker `iptables:false` integration, fail-safe ordering, Molecule tests. The natural
|
||||
next spec.
|
||||
2. **OPNsense-as-code** — tooling mechanism + cross-VLAN rule rendering.
|
||||
3. **Drift-detection check** — if/when built.
|
||||
|
||||
## Related
|
||||
|
||||
ADR-002 (security baseline: nftables default-deny, fail2ban, blast radius),
|
||||
ADR-004 (Docker model: `iptables:false`), ADR-007 (network topology, VLANs, OPNsense,
|
||||
per-VLAN egress), ADR-016 (NetBird mesh: SSH on `wt0` only), ADR-019 (`firewall` tag).
|
||||
````
|
||||
|
||||
- [ ] **Step 2: Verify the file is well-formed**
|
||||
|
||||
Run:
|
||||
```bash
|
||||
test -f docs/decisions/020-firewall.md && grep -c "^## " docs/decisions/020-firewall.md
|
||||
```
|
||||
Expected: exit 0 and a printed count of `7` (the H2 sections: Status, Context, Decision, Guardrails, Consequences, Scope, Related — H3 subsections under Decision are not counted by `^## `).
|
||||
|
||||
- [ ] **Step 3: Commit**
|
||||
|
||||
```bash
|
||||
git add docs/decisions/020-firewall.md
|
||||
git commit -m "docs(adr): ADR-020 firewall strategy (two-layer + shared catalog)"
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### Task 2: Wire ADR-020 into CLAUDE.md
|
||||
|
||||
**Files:**
|
||||
- Modify: `CLAUDE.md` (Further reading table; firewall guardrail bullet)
|
||||
|
||||
- [ ] **Step 1: Add ADR-020 to the Further reading table**
|
||||
|
||||
In `CLAUDE.md`, find this row (around line 225):
|
||||
|
||||
```markdown
|
||||
| Tagging & run-targeting | `docs/decisions/019-tagging.md` |
|
||||
```
|
||||
|
||||
Add this row immediately after it:
|
||||
|
||||
```markdown
|
||||
| Firewall strategy | `docs/decisions/020-firewall.md` |
|
||||
```
|
||||
|
||||
(Exact column padding need not match perfectly — just produce a valid Markdown table row consistent with the surrounding rows.)
|
||||
|
||||
- [ ] **Step 2: Harden the firewall guardrail bullet**
|
||||
|
||||
In `CLAUDE.md`, find this bullet (around line 172, under "What Claude must not do without explicit instruction"):
|
||||
|
||||
```markdown
|
||||
- Open a firewall port anywhere but the `group_vars` firewall definitions — never ad-hoc on a host (ADR-002)
|
||||
```
|
||||
|
||||
Replace it with:
|
||||
|
||||
```markdown
|
||||
- Open a firewall port anywhere but the `group_vars` service catalog — never ad-hoc on a host. If it's not in the catalog, it doesn't exist (ADR-002, ADR-020)
|
||||
```
|
||||
|
||||
- [ ] **Step 3: Verify both edits**
|
||||
|
||||
Run:
|
||||
```bash
|
||||
grep -n "020-firewall" CLAUDE.md && grep -n "service catalog" CLAUDE.md
|
||||
```
|
||||
Expected: the Further reading row matches `020-firewall`, and the guardrail bullet now contains "service catalog".
|
||||
|
||||
- [ ] **Step 4: Commit**
|
||||
|
||||
```bash
|
||||
git add CLAUDE.md
|
||||
git commit -m "docs: link ADR-020; harden firewall guardrail to the service catalog"
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### Task 3: Mark TODO 3.5 decided
|
||||
|
||||
**Files:**
|
||||
- Modify: `docs/TODO.md` (item 3.5)
|
||||
|
||||
- [ ] **Step 1: Strike through and annotate item 3.5**
|
||||
|
||||
In `docs/TODO.md`, find this line (around line 26):
|
||||
|
||||
```markdown
|
||||
5. Decide the firewall strategy (which firewall, ruleset, per-host vs central).
|
||||
```
|
||||
|
||||
Replace it with:
|
||||
|
||||
```markdown
|
||||
5. ~~Decide the firewall strategy (which firewall, ruleset, per-host vs central).~~
|
||||
DECIDED (ADR-020): two layers — OPNsense (perimeter + inter-VLAN) + host nftables
|
||||
(default-deny inbound + east-west allowlist, permissive egress). Single source of
|
||||
truth: a `group_vars` service catalog with symbolic sources; each layer renders
|
||||
its own slice. Builds deferred to follow-up specs (host nftables in `base`, then
|
||||
OPNsense-as-code).
|
||||
```
|
||||
|
||||
- [ ] **Step 2: Verify**
|
||||
|
||||
Run: `grep -n "DECIDED (ADR-020)" docs/TODO.md`
|
||||
Expected: one match on the item 3.5 annotation.
|
||||
|
||||
- [ ] **Step 3: Commit**
|
||||
|
||||
```bash
|
||||
git add docs/TODO.md
|
||||
git commit -m "docs(todo): mark 3.5 firewall strategy decided (ADR-020)"
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### Task 4: Update CAPABILITIES.md firewall note
|
||||
|
||||
**Files:**
|
||||
- Modify: `docs/CAPABILITIES.md` (the firewall parenthetical in §1 Edge & networking, around line 32)
|
||||
|
||||
- [ ] **Step 1: Point the firewall note at ADR-020**
|
||||
|
||||
In `docs/CAPABILITIES.md`, find this line (around line 32, just under the §1 table):
|
||||
|
||||
```markdown
|
||||
_(DHCP, firewall, mDNS reflection live on OPNsense — Ansible-managed, not containers.)_
|
||||
```
|
||||
|
||||
Replace it with:
|
||||
|
||||
```markdown
|
||||
_(DHCP, firewall, mDNS reflection live on OPNsense — Ansible-managed, not containers.)_
|
||||
|
||||
_Firewalling is two-layer (ADR-020): OPNsense at the perimeter + inter-VLAN, plus
|
||||
per-host `nftables` (default-deny inbound + east-west allowlist) rendered by the `base`
|
||||
role from a shared `group_vars` service catalog. Both layers are still to be built._
|
||||
```
|
||||
|
||||
- [ ] **Step 2: Verify and run the full lint suite**
|
||||
|
||||
Run:
|
||||
```bash
|
||||
grep -n "ADR-020" docs/CAPABILITIES.md && make lint
|
||||
```
|
||||
Expected: the new ADR-020 note is found, and `make lint` passes (yamllint clean, ansible-lint clean, `check-tags: OK`).
|
||||
|
||||
- [ ] **Step 3: Commit**
|
||||
|
||||
```bash
|
||||
git add docs/CAPABILITIES.md
|
||||
git commit -m "docs(capabilities): note two-layer firewall model (ADR-020)"
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Final verification
|
||||
|
||||
- [ ] Confirm cross-references resolve:
|
||||
```bash
|
||||
ls docs/decisions/020-firewall.md && grep -rl "ADR-020\|020-firewall" CLAUDE.md docs/TODO.md docs/CAPABILITIES.md
|
||||
```
|
||||
Expected: the ADR file exists and all three living docs reference it.
|
||||
- [ ] `make lint` passes end to end.
|
||||
- [ ] `git log --oneline -4` shows the four task commits.
|
||||
- [ ] Sanity: the ADR's *Scope* section names the two deferred build specs (host nftables in `base`, OPNsense-as-code) so the next brainstorm has an obvious starting point.
|
||||
164
docs/superpowers/specs/2026-06-06-firewall-strategy-design.md
Normal file
164
docs/superpowers/specs/2026-06-06-firewall-strategy-design.md
Normal file
|
|
@ -0,0 +1,164 @@
|
|||
# Design — Firewall strategy (two-layer model + shared catalog)
|
||||
|
||||
- **Date:** 2026-06-06
|
||||
- **Status:** Approved design — pending implementation plan
|
||||
- **Resolves:** TODO 3.5 ("Decide the firewall strategy — which firewall, ruleset,
|
||||
per-host vs central")
|
||||
- **Becomes:** ADR-020 (this design is the basis for that ADR)
|
||||
- **Scope note:** This is the **strategy** ADR. It pins the architecture and
|
||||
responsibilities; the detailed builds (host nftables in `base`, OPNsense-as-code) are
|
||||
separate follow-up specs (see *Scope*).
|
||||
|
||||
---
|
||||
|
||||
## Problem
|
||||
|
||||
boma needs a firewall strategy that is **predictable, declarative, and defends the
|
||||
stated threat model** (opportunistic external, lateral movement / blast radius,
|
||||
operator/agent error — ADR-002). The ADRs already commit to pieces of this — `nftables`
|
||||
default-deny on hosts (ADR-002), OPNsense at the perimeter (ADR-007), Docker with
|
||||
`iptables: false` (ADR-004) — but no document ties them together: *which layer owns
|
||||
what, where firewall intent is declared, and how the two layers stay consistent.*
|
||||
Without that, ports drift open ad-hoc and "per-host vs central" stays unanswered.
|
||||
|
||||
The roles that would hold the host firewall (`base`, `docker_host`) are empty, and there
|
||||
is no OPNsense automation yet — so this is greenfield strategy work.
|
||||
|
||||
## The two-layer model
|
||||
|
||||
Two firewall layers, each with a distinct job; the host layer adds deliberate
|
||||
defense-in-depth for the one thing the perimeter structurally cannot see.
|
||||
|
||||
### OPNsense — perimeter + inter-VLAN
|
||||
|
||||
Owns everything *between zones* and at the edge:
|
||||
|
||||
- WAN edge (the internet boundary).
|
||||
- Inter-VLAN policy: `lan`/`iot`/`guest` → `srv`, `mgmt` access, the documented
|
||||
per-VLAN egress rules (ADR-007).
|
||||
- **Structurally blind to intra-`srv` traffic**: services share the `srv` subnet
|
||||
(VLAN 20), which is switched and never reaches the OPNsense gateway.
|
||||
|
||||
### Host nftables — host-local + east-west within `srv` (in `base`)
|
||||
|
||||
Runs on every Debian VM:
|
||||
|
||||
- **Default-deny inbound**; allow loopback + established/related.
|
||||
- **East-west allowlist**: a service host accepts a connection only from declared
|
||||
sources (e.g. the reverse proxy, a named peer). This is the lateral-movement control
|
||||
OPNsense cannot provide — the blast-radius goal in ADR-002.
|
||||
- **Permissive egress**: allow outbound + established/related. Per-VLAN egress
|
||||
restriction stays at OPNsense (where it already lives, ADR-007). Rationale: host-level
|
||||
egress allowlisting is high-friction (every DNS/NTP/update/registry/webhook call must
|
||||
be enumerated) for limited additional benefit given OPNsense already bounds where each
|
||||
VLAN can go.
|
||||
- **Docker integration**: Docker daemon runs with `"iptables": false`; nftables owns all
|
||||
filtering, including container traffic (ADR-004).
|
||||
- **Guaranteed management plane**: loopback, established/related, and `wt0` (the NetBird
|
||||
overlay, ADR-016) for SSH + Ansible are *always* allowed, independent of the catalog,
|
||||
and the ruleset is applied atomically — so a malformed or empty catalog can never lock
|
||||
out management. (ADR-016: SSH is allowed only on `wt0`, not the LAN.)
|
||||
|
||||
## The shared service catalog (single source of truth)
|
||||
|
||||
A central, declarative **service catalog** in `group_vars/` is the one source of truth
|
||||
for firewall intent. This aligns with ADR-002's existing rule that "port definitions
|
||||
live in `group_vars/` so rules stay in sync with deployed services," and keeps
|
||||
connectivity *topology* (inherently cross-cutting) in inventory rather than in any one
|
||||
self-contained service role (ADR-004).
|
||||
|
||||
Each entry describes a service's **ingress** as a list of allow rules:
|
||||
|
||||
```yaml
|
||||
photoprism:
|
||||
ingress:
|
||||
- { from: reverse_proxy, port: 2342, proto: tcp }
|
||||
reverse_proxy:
|
||||
ingress:
|
||||
- { from: lan, port: 443, proto: tcp }
|
||||
```
|
||||
|
||||
`from` is **symbolic**, resolved at render time:
|
||||
|
||||
- a **host or group** → IP(s) from inventory;
|
||||
- a **role** (e.g. `reverse_proxy`) → the host(s) filling it;
|
||||
- a **VLAN/zone** (e.g. `lan`) → the subnet from the ADR-007 table.
|
||||
|
||||
Symbolic sources keep the catalog readable and resilient to IP changes.
|
||||
|
||||
### Each layer renders only its own slice
|
||||
|
||||
The same catalog feeds both layers; each filters for the rules it owns:
|
||||
|
||||
| Ingress rule | Host nftables | OPNsense |
|
||||
|---|---|---|
|
||||
| `from: reverse_proxy` (a `srv` peer) | allow proxy IP → port | — (intra-`srv`, invisible) |
|
||||
| `from: lan` (cross-VLAN) | allow `lan` subnet → port | allow `lan` → host:port |
|
||||
|
||||
The dominant pattern falls out naturally: most services are **proxied** — their only
|
||||
ingress is `from: reverse_proxy`; users reach them *through* the reverse proxy, which
|
||||
alone carries `from: lan, port: 443`. This matches "services sit behind the reverse
|
||||
proxy with authentication" (ADR-002).
|
||||
|
||||
"Shared catalog, each layer renders its own" was chosen over a single
|
||||
connectivity-model-generates-both (too much machinery, tight coupling of two very
|
||||
different rule domains) and over fully independent per-layer declarations (real drift
|
||||
risk: a port opened on the host but not at OPNsense, or vice versa).
|
||||
|
||||
## OPNsense automation — owned here, mechanism deferred
|
||||
|
||||
OPNsense is **Ansible-managed** (CLAUDE.md: "OPNsense is entirely Ansible; do not reach
|
||||
for a Terraform OPNsense provider"). It renders the **cross-VLAN slice** of the catalog
|
||||
(every `from: <other-zone>` rule) plus the static ADR-007 facts (WAN edge, per-VLAN
|
||||
egress, mgmt access, inter-VLAN defaults).
|
||||
|
||||
This ADR pins **what** OPNsense owns and that it renders from the shared catalog. The
|
||||
**how** — config-XML templating vs the OPNsense API vs a plugin — is a substantial,
|
||||
separate tooling decision, **deferred to the OPNsense-as-code follow-up spec**. Recorded
|
||||
here as an explicit open sub-decision so it is not lost.
|
||||
|
||||
## Guardrails & enforcement
|
||||
|
||||
- **The catalog is authoritative.** If a port is not in the catalog, it does not exist.
|
||||
This hardens the existing CLAUDE.md guardrail ("never open a firewall port ad-hoc on a
|
||||
host") into a positive contract.
|
||||
- **The `firewall` tag** (ADR-019) marks firewall tasks, so `--tags firewall` re-renders
|
||||
rules on `base` and any service role that contributes them.
|
||||
- **Drift detection (aspiration).** A deterministic check — in the spirit of
|
||||
`scripts/check-tags.py` — compares each host's actual listening ports / live `nft`
|
||||
ruleset against the catalog and flags anything undeclared. Ties to TODO 8.5
|
||||
(`/security-review`) and the "undeclared open ports" pre-scan idea. Listed as a
|
||||
consequence and future guardrail; not necessarily built in the first implementation.
|
||||
|
||||
## Consequences
|
||||
|
||||
- "Per-host vs central" is answered: **both**, with clear ownership — central perimeter
|
||||
(OPNsense) + per-host default-deny with east-west allowlisting, fed by one catalog.
|
||||
- Lateral movement within `srv` is constrained (the gap OPNsense can't close).
|
||||
- One declarative catalog means no ad-hoc ports and no cross-layer drift on the shared
|
||||
facts (ports, IPs, sources).
|
||||
- Cost: the catalog and the render-per-layer machinery must be built and maintained;
|
||||
east-west allowlisting adds per-service ingress declarations (mitigated by the
|
||||
proxied-by-default pattern, which keeps most entries to a single line).
|
||||
|
||||
## Scope
|
||||
|
||||
**This ADR decides:** the two-layer model and each layer's responsibilities; host
|
||||
nftables = default-deny inbound + east-west allowlist + permissive egress + guaranteed
|
||||
management plane + Docker `iptables:false`; the shared `group_vars` service catalog as
|
||||
single source of truth with symbolic sources; each layer renders its own slice; the
|
||||
no-ad-hoc-ports guardrail.
|
||||
|
||||
**Deferred to follow-up specs (each its own brainstorm → plan):**
|
||||
|
||||
1. **Host nftables implementation** in `base` — exact catalog schema, nftables template
|
||||
structure, Docker `iptables:false` integration, fail-safe ordering, Molecule tests.
|
||||
The natural next spec.
|
||||
2. **OPNsense-as-code** — the tooling mechanism + cross-VLAN rule rendering.
|
||||
3. **Drift-detection check** — if/when we build it.
|
||||
|
||||
## Related
|
||||
|
||||
ADR-002 (security baseline: nftables default-deny, fail2ban, blast radius),
|
||||
ADR-004 (Docker model: `iptables:false`), ADR-007 (network topology, VLANs, OPNsense,
|
||||
per-VLAN egress), ADR-016 (NetBird mesh: SSH on `wt0` only), ADR-019 (`firewall` tag).
|
||||
Loading…
Add table
Reference in a new issue