docs(website): correct the CSP delta to one directive and document the report sink #51

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whitlocktech merged 1 commits from feature/csp-report-only into main 2026-07-27 20:22:30 +00:00
3 changed files with 94 additions and 16 deletions
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@@ -181,22 +181,64 @@ form-action 'self';
frame-ancestors 'none';
```
Delta vs. the policy in `server/src/app.js` today — the whole change is two directives:
Delta vs. the policy in `server/src/app.js` today. This was written as two directives; on
implementation it turned out to be **one**:
- **Add `form-action 'self'`** (currently absent) — blocks an injected `<form action="https://evil">`
from POSTing credentials off-origin, an exfil path `connect-src` doesn't cover.
- **Tighten `frame-ancestors`** `'self'``'none'` — nothing legitimately frames the site.
- ~~**Add `form-action 'self'`** (currently absent)~~**it was not absent.** The directives object in
`app.js` does not list it, but the middleware is configured `useDefaults: true`, and helmet's default
set already supplies `form-action 'self'` — so the header served in production has carried it all
along. Verified by capturing the live `Content-Security-Policy` header from the running app rather
than reading the config, which is how the plan got this wrong. **No behavioural change here.** It is
now written out explicitly in `config/csp.js` anyway: a security directive should not depend on a
third-party library's defaults surviving its next major version.
- **Tighten `frame-ancestors`** `'self'``'none'` — nothing legitimately frames the site. **This is
the entire behavioural delta of the phase.**
- Unchanged: `default-src`, `script-src`, `connect-src`, `object-src 'none'`, `base-uri 'self'`, and
`img-src … https:` (external `BRAND_*` logo/hero and `<img>` in sanitized wiki/news bodies rely on
`https:`).
The soak is still worth running for that one directive, and arguably it is the directive that most
needs one: a `frame-ancestors` report is generated by the browser of *whoever framed the site*, so it
is the only way to discover that something legitimately embeds us before the enforcing policy breaks
it. Nothing else can tell us that.
**Rollout:** ship via `Content-Security-Policy-Report-Only` with `report-to` for one release, watch for
violations, then flip to enforce.
Before trusting `script-src 'self'`: Vite's build injects an inline modulepreload-polyfill `<script>`
into `dist/index.html`, which that directive blocks (harmless, but throws a violation). Confirm it's
disabled or set `build.modulepreload.polyfill = false` in the Vite config. (The `renderIndexHtml`
branding injection adds only `<meta>`/`<link>` tags — no inline script, no nonce needed.)
into `dist/index.html`, which that directive blocks (harmless, but throws a violation).
**Already handled**`client/vite.config.js` sets `modulePreload: { polyfill: false }`, so the build
emits no inline bootstrap script. (The `renderIndexHtml` branding injection adds only `<meta>`/`<link>`
tags — no inline script, no nonce needed.)
### Where reports go
`report-to` needs somewhere to point, so the report-only PR stands up a same-origin sink:
**`POST /api/csp-report`** (`server/src/router/cspReport.controller.js`, wired in `app.js`). Same-origin
on purpose — violation reports describe attacks against this site and are not handed to a third-party
collector. It writes to the `csp` log tag and stores nothing.
It is mounted outside `/api/v1`, alongside `/api/health`: the browser learns the path from the policy
header, never from a client build, so it is not part of the versioned client contract. This is the
`+1` in the route manifest that made PR 0 go first (see § Sequencing).
Necessary properties, since it is an unauthenticated public `POST` (browsers send reports with no
session, and gating it would silence exactly the anonymous visitors worth hearing about):
- **Both wire formats.** `report-uri` (Firefox, Safari) sends `application/csp-report` with a single
hyphenated-key object; `report-to` (Chrome) sends `application/reports+json` with an array of
camelCase envelopes. Handling one silently drops half the browsers. Both directives are emitted, and
`report-to` additionally needs a `Reporting-Endpoints` response header or it is inert.
- **Always 204, even for junk.** A 4xx would make the global error handler write an ERROR line quoting
the attacker-supplied body — turning an open endpoint into a log-flood primitive. A browser cannot
act on an error from a report sink anyway.
- **Bounded everywhere:** 16 KB body cap, a per-IP rate limit, a fixed field allowlist, and every
logged field truncated (`script-sample` is attacker-influenced and can carry a whole inline script).
**Retiring it:** the sink exists for the soak. When the tightened policy flips to enforced and the
report-only twin is deleted, this endpoint goes with it — *unless* a `report-to` group is deliberately
kept on the enforced policy, which is a reasonable thing to want. Decide that in the enforce PR rather
than leaving an orphan route behind.
Tracked follow-ups (own PRs):
@@ -302,9 +344,11 @@ proves it, with no router file moved.
is stable). The manifest keeps only `/api/**`, `/.well-known/**`, and the internal app's routes, so
it does not change depending on whether CI built the client. Static mounts are not API contract.
- **The baseline already exists:** [`api-route-inventory.json`](./api-route-inventory.json) in this
directory is today's frozen surface — **199 API routes** (110 of them `/api/v1/admin`) plus 2
internal. PR 0's generator must **reproduce this file byte-for-byte**; that is PR 0's own acceptance
test, and it means the freeze is already in effect before the first router moves.
directory is the frozen surface — **199 API routes** (110 of them `/api/v1/admin`) plus 2
internal at the time PR 0 was written. PR 0's generator must **reproduce this file byte-for-byte**;
that is PR 0's own acceptance test, and it means the freeze is already in effect before the first
router moves. *(It did, on first run. The file has since moved to **200** — the CSP report-only PR
added `POST /api/csp-report`, the first deliberate, reviewed manifest diff.)*
- **Runtime introspection, not source parsing.** It is authoritative about mounts, and the route paths
in `admin.routes.js` sit on the line *after* `adminRouter.get(`, which defeats naive greps.
- **Not `swagger-output.json`.** That is annotation-derived (only annotated routes appear) and churns
@@ -341,8 +385,11 @@ deliberate `+1` in the manifest — which is exactly the mechanism working as de
1. **PR 0 — route manifest.** Generator + CI check + committed baseline of today's surface. No routers moved. ✅ landed
2. **PR — CSP report-only.** Tightened policy behind `Content-Security-Policy-Report-Only` + `report-to`,
plus the report collector (manifest `+1`).
3. **PR — CSP enforce.** One release later, assuming a clean violation report.
plus the report collector (manifest `+1` — the first deliberate, reviewed manifest diff). ✅ landed
3. **PR — CSP enforce.** One release later, assuming a clean violation report. **Blocked on real soak
data**, not on code: watch the `csp` log tag for `frame-ancestors` reports across one release before
flipping. Also decide there whether `/api/csp-report` is retired with the report-only twin or kept
as a `report-to` group on the enforced policy.
4. **PR 1 — admin:** `users`, `account`, `invites`, `auth` (providers).
5. **PR 2 — admin:** `moderation`, `bot-activity`, `activity`.
6. **PR 3 — admin (content):** `posts`, `pages`, `wiki`, `uploads`.

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@@ -270,7 +270,7 @@ are authoritative, and they answer different questions:
| Artifact | Source of truth for | Generated by |
|---|---|---|
| `server/routes.manifest.json` — mirrored as [api-route-inventory.json](./api-route-inventory.json) | **What URLs exist.** 199 public routes + 2 on the internal listener, sorted, method + path only. | `npm run routes:manifest`, by walking the live Express stack |
| `server/routes.manifest.json` — mirrored as [api-route-inventory.json](./api-route-inventory.json) | **What URLs exist.** 200 public routes + 2 on the internal listener, sorted, method + path only. | `npm run routes:manifest`, by walking the live Express stack |
| `server/swagger/swagger-output.json` — served at `/api/docs` | **What each route means.** Parameters, bodies, response codes, security. | `npm run swagger`, from `#swagger.*` annotations |
The split is deliberate: Swagger is annotation-derived, so an unannotated route is invisible in it and
@@ -490,7 +490,8 @@ who"; `activity_log` provides the history feed.
- **bcrypt** hashing (cost 10+); plaintext passwords never stored, logged, or returned.
- **Rate limiting** (`express-rate-limit`) on `/auth/login` and `/public/contact`.
- **Validation** (`express-validator`) on all writes; centralized error handler.
- **helmet** with a Content-Security-Policy tuned for the built React SPA (see `server/src/app.js`):
- **helmet** with a Content-Security-Policy tuned for the built React SPA. The policies now live in
**`server/src/config/csp.js`** (`app.js` only wires them up):
`default-src 'self'`; `script-src 'self'` (the Vite build emits only external module chunks — the
inline module-preload polyfill is disabled in `client/vite.config.js` to keep this valid);
`style-src 'self' 'unsafe-inline' https://fonts.googleapis.com` (React's pervasive inline
@@ -498,11 +499,33 @@ who"; `activity_log` provides the history feed.
https://fonts.gstatic.com` (Cinzel); `img-src 'self' data: https:` (same-origin uploads, plus
external https images embedded in wiki/news bodies or `BRAND_*` logo/hero/favicon); `connect-src
'self'` (REST + SSE are same-origin); `frame-ancestors 'self'`; `object-src 'none'`; `base-uri
'self'`. `upgrade-insecure-requests` is intentionally **not** set (TLS terminates at the proxy, there
'self'`; `form-action 'self'` (blocks an injected `<form action="https://evil">` from POSTing
credentials off-origin — an exfil path `connect-src` does not cover; it was always emitted via
helmet's `useDefaults` and is now pinned explicitly so it cannot vanish under a helmet upgrade).
`upgrade-insecure-requests` is intentionally **not** set (TLS terminates at the proxy, there
are no mixed-content subresources, and it would break a local `npm start` over plain http). The
`/api/docs` Swagger UI route gets a **looser** policy that additionally allows inline script/style,
since swagger-ui-express injects an inline bootstrap. helmet also strips `X-Powered-By`; the two
internal-only listeners (`internalApp.js`, `bot/src/app.js`) disable it explicitly too.
- **A second, tightened policy ships alongside on `Content-Security-Policy-Report-Only`** for one
release before it replaces the enforced one (`docs/website/API_V2_PLAN.md` § Phase 1). It is derived
from the enforced policy so the two cannot drift, and differs by exactly one directive:
`frame-ancestors 'self'`**`'none'`**. Serving both headers at once means the live policy keeps
protecting users while anything the tightened version would break arrives as a report rather than as
a broken page — and for `frame-ancestors` specifically, a report from the browser of whoever framed
the site is the only way to learn that something does.
- **`POST /api/csp-report`** is the same-origin violation sink that `report-to` / `report-uri` point at
(`report-to` additionally requires the `Reporting-Endpoints` response header, which is set alongside).
Same-origin on purpose: reports describe attacks against this site and are not handed to a
third-party collector. It parses **both** wire formats (`application/csp-report` from Firefox/Safari,
`application/reports+json` from Chrome's Reporting API — handling one drops half the browsers),
writes to the `csp` log tag and **stores nothing**. Necessarily unauthenticated (browsers send
reports with no session), so it is bounded on every axis: 16 KB body cap, per-IP rate limit, fixed
field allowlist, every logged field truncated, and **always 204 — even for malformed input**, since a
4xx would make the global error handler log the attacker-supplied body and turn an open endpoint into
a log-flood primitive. Mounted outside `/api/v1` next to `/api/health`: the browser learns the path
from the policy header, never from a client build, so it is not part of the versioned client
contract.
- **Admin not indexed**: `X-Robots-Tag: noindex, nofollow` on `/api/v1/admin` and the admin SPA routes; `robots.txt` disallows `/admin`.
- **No directory browsing** (express.static doesn't list; no `serve-index`).
- **No hardcoded credentials**: first admin via `seed.js` reading `ADMIN_USERNAME`/`ADMIN_PASSWORD` from env (created only if no users exist); `.env` git-ignored, `.env.example` committed.
@@ -527,7 +550,11 @@ instead. Errors never leak credentials.
`utils/logger.js` — a small dependency-free logger with **two transports, console + file**,
and four levels (`error`/`warn`/`info`/`debug`). Each line is timestamped and tagged by
subsystem (`[server]`, `[http]`, `[db]`, `[auth]`, `[admin]`, `[ratelimit]`, …).
subsystem (`[server]`, `[http]`, `[db]`, `[auth]`, `[admin]`, `[ratelimit]`, `[csp]`, …).
> During the CSP report-only soak, `[csp]` is the tag to watch: a `csp violation` warn line with
> `directive: frame-ancestors` means something really does frame the site and the enforce PR would
> break it. Silence across one release is the green light to flip.
- **Console**: color on a TTY, plain in Docker; verbosity = `LOG_LEVEL` (default `info`).
- **File**: plain text appended to `LOG_DIR/LOG_FILE` (default `<server>/logs/app.log`,

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@@ -5,6 +5,10 @@
"method": "GET",
"path": "/.well-known/assetlinks.json"
},
{
"method": "POST",
"path": "/api/csp-report"
},
{
"method": "GET",
"path": "/api/docs.json"