julien
da2bd6d481
## Summary Documents the security middleware stack shipped across the five most recent BFF PRs (#115, #117, #120, #122, #123) as a single MADR ADR. Today the rationale for each choice lives in code comments and PR descriptions; the next contributor reaching for `csurf`, a cookie-only CSRF, or a hardcoded localhost CORS fallback won't have a single place to read why those are wrong here. ADR-0021 covers: - **Response envelope** — `{ error: { code, message, traceId } }`, single contract shared between Nest's `StructuredErrorFilter` and raw Express middlewares (CSRF, rate-limit) via the exported `errorResponse()` helper. Status code → code mapping documented. 500s never leak the underlying exception. - **CSRF — session-bound double-submit**, not pure cookie-vs-header. Rationale: a subdomain-takeover cookie injection can't bypass the comparison because the source of truth is the server-side session token, not the cookie. Cookie is the SPA's read-only mirror. - **CORS allowlist** — `CORS_ALLOWED_ORIGINS` mandatory at boot, no fallback. "Works in dev, breaks in prod" is the exact trap the validator catches. - **Rate limiting** — buckets keyed by session id (auth) or IP (anonymous), 10/min on `/auth/login` + `/auth/callback`, 120/min general, `/api/health` skipped. In-memory v1 store; Redis-backed migration is one constructor arg. - **Helmet config** — defaults plus three overrides (HSTS prod-only, `crossOriginResourcePolicy: cross-origin`, CSP prod-only). Each override has a code-anchored justification. ## Scope This is the **implementation-level** security ADR. The **strategic** security baseline ADR — OWASP ASVS reference level, HDS / GDPR / NIS 2 framing, RSSI sign-off — remains paused per the note in [CLAUDE.md](CLAUDE.md). When that ADR lands it'll either confirm 0021 or supersede pieces of it; 0021 is explicit about which choices are tactical and revisitable. ## Notable structural choices in the ADR - **"Considered Options" mirrors the actual debate.** For CSRF: session-bound vs pure double-submit vs `csurf` vs synchronizer. For rate-limit bucket key: sessionID-then-IP vs IP-only vs Entra `oid`. Each rejected option has its "Bad, because …" so the reader sees why we didn't go that way. - **Each "Decision Outcome" line points at the file / function that enforces it.** Cross-references are absolute paths so they survive folder reorgs. - **The "Consequences" section is brutally honest about trade-offs.** In-memory rate-limit doesn't scale horizontally. The CSRF cookie is XSS-readable. No `details` field in the envelope for field-level validation errors yet. These aren't hidden in the prose. ## Other doc touches - [docs/decisions/README.md](docs/decisions/README.md) index entry added. - [notes/handoff.md](notes/handoff.md) refreshed (gitignored; not part of the commit but useful for the next session). ## Noted for a separate PR (out of scope here) [CLAUDE.md](CLAUDE.md) §"Repository status" still says "The Nx workspace is **not yet bootstrapped**" and refs ADRs up to 0020. The whole paragraph is stale (the project is fully scaffolded, 22 ADRs in place). Worth a small dedicated docs PR. ## Test plan - [x] `pnpm exec prettier --check docs/decisions/` → clean. - [x] ADR follows the MADR 4.0.0 template (frontmatter with `status`, `date`, `decision-makers`, `tags`; sections in the canonical order). - [x] Tags drawn from the vocabulary in [docs/decisions/README.md](docs/decisions/README.md#tag-vocabulary): `security`, `backend`. - [x] Index in `docs/decisions/README.md` updated in the same change. - [x] Cross-references to ADRs 0009, 0010, 0012, 0015 verified. - [ ] Renders in Gitea / IDE markdown preview without parser warnings. --------- Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr> Reviewed-on: #124
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9.2 KiB
Markdown
68 lines
9.2 KiB
Markdown
# Architectural Decision Records
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This project records architecturally-significant decisions as **ADRs** in the [MADR 4.0.0](https://github.com/adr/madr) format. References: [adr.github.io](https://adr.github.io/).
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## Why ADRs
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ADRs capture the _why_ behind a decision — context, drivers, options considered, trade-offs accepted — at the moment the decision is made. They make architecture reviewable, onboarding faster, and prevent the same debate from being re-litigated later.
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## Conventions
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- **Format:** MADR 4.0.0. Start from [template.md](template.md).
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- **Filename:** `NNNN-kebab-case-title.md`, e.g. `0007-adopt-tailwind-for-design-tokens.md`.
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- **Numbering:** globally sequential 4-digit prefix. Numbers never reset, never get reused — even when an ADR is superseded or deprecated.
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- **Layout:** flat folder. ADRs are not nested into category subfolders; topical organization happens via tags.
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- **Tags:** every ADR carries a `tags:` array in the MADR frontmatter, drawn from the [tag vocabulary](#tag-vocabulary) below. An ADR may carry several tags. Propose new tags (or renames) in the same PR that needs them; never invent ad-hoc tags inline.
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- **Status lifecycle:** `proposed` → `accepted` → optionally `deprecated` or `superseded by [ADR-NNNN](NNNN-other.md)`. Update the YAML frontmatter; never delete an ADR.
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- **Index maintenance:** every ADR addition or status change must update the [Index](#index) below in the same commit.
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## When to write an ADR
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Write one whenever a development decision is non-trivial: tool or library choice, framework pattern, security control, perf budget, a11y target, naming convention, deprecation, breaking change, or any choice that future contributors would benefit from understanding the _why_ of.
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## Tag vocabulary
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The vocabulary below is the source of truth. It is intentionally coarse — propose extensions only when an existing tag genuinely doesn't fit, and avoid overly narrow tags.
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| Tag | Scope |
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| ---------------- | ------------------------------------------------------------------- |
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| `frontend` | UI, Angular, components, design system, client-side state |
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| `backend` | API, BFF, server-side services |
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| `security` | AuthN, AuthZ, sessions, CSP, dependency scanning, secret management |
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| `performance` | Perf budgets, caching, bundle size, Lighthouse |
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| `accessibility` | WCAG, a11y testing, keyboard, ARIA, contrast |
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| `infrastructure` | CI/CD, hosting, deployment, runtime |
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| `observability` | Logs, metrics, traces, correlation IDs, monitoring |
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| `data` | Persistence, schemas, migrations, data flow |
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| `process` | Team conventions, workflows, repo policy |
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> _Status: starter vocabulary, to be refined as ADRs accumulate. Update this table whenever a tag is added, renamed, or retired._
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## Index
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ADRs are listed in numerical order. To slice by topic, filter on the `Tags` column.
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| # | Title | Status | Tags | Date |
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| ------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------- | -------- | -------------------------------------------------------------- | ---------- |
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| [0001](0001-use-adrs-to-record-architectural-decisions.md) | Use ADRs to record architectural decisions | accepted | `process` | 2026-04-29 |
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| [0002](0002-adopt-nx-monorepo-apps-preset.md) | Adopt Nx monorepo with the `apps` preset | accepted | `infrastructure`, `frontend`, `backend` | 2026-04-29 |
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| [0003](0003-workspace-and-app-naming-convention.md) | Workspace and app naming convention | accepted | `process` | 2026-04-29 |
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| [0004](0004-frontend-stack-angular-csr-zoneless-signals.md) | Frontend stack — Angular (latest LTS), standalone, zoneless, Signals, CSR-only, Vitest | accepted | `frontend` | 2026-04-29 |
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| [0005](0005-backend-stack-nestjs.md) | Backend stack — NestJS over Express, Fastify, Hono | accepted | `backend` | 2026-04-29 |
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| [0006](0006-persistence-postgresql-prisma.md) | Persistence — PostgreSQL with Prisma | accepted | `data`, `backend` | 2026-04-29 |
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| [0007](0007-pre-commit-hooks-and-conventional-commits.md) | Pre-commit hooks and Conventional Commits | accepted | `process` | 2026-04-29 |
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| [0008](0008-identity-model-entra-workforce-dual-audience.md) | Identity model — multi-tenant Entra ID for workforce, dual-audience design for future External ID | accepted | `security`, `data` | 2026-04-29 |
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| [0009](0009-auth-flow-oidc-pkce-msal-node.md) | Authentication flow — OIDC Authorization Code + PKCE via MSAL Node, BFF session pattern | accepted | `security`, `backend` | 2026-04-29 |
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| [0010](0010-session-management-redis.md) | Session management — opaque session IDs in cookies, payload in self-hosted Redis with AES-GCM at rest | accepted | `security`, `backend`, `infrastructure` | 2026-04-29 |
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| [0011](0011-mfa-enforcement-entra-conditional-access.md) | MFA enforcement — Entra ID Conditional Access baseline, BFF claim sanity-check, step-up hooks designed-in | accepted | `security` | 2026-04-29 |
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| [0012](0012-observability-pino-opentelemetry.md) | Observability — Pino structured logs + OpenTelemetry tracing, W3C Trace Context propagation, stdout + collector | accepted | `observability`, `backend`, `frontend` | 2026-04-29 |
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| [0013](0013-audit-trail-separated-postgres-append-only.md) | Audit trail — separated append-only Postgres schema, decoupled from app logs | accepted | `security`, `observability`, `data` | 2026-04-29 |
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| [0014](0014-downstream-api-access-obo-pattern.md) | Downstream API access — On-Behalf-Of pattern, unified `DownstreamApiClient`, audience-aware authorization | accepted | `security`, `backend` | 2026-04-29 |
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| [0015](0015-cicd-gitea-actions.md) | CI/CD pipeline — Gitea Actions, trunk-based + squash-merge, thin YAML over portable scripts | accepted | `infrastructure`, `process` | 2026-04-30 |
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| [0016](0016-accessibility-baseline-wcag-aa-targeted-aaa.md) | Accessibility baseline — WCAG 2.2 AA + targeted AAA, Angular CDK + spartan-ng + Tailwind, APF panel testing | accepted | `accessibility`, `frontend`, `process` | 2026-04-30 |
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| [0017](0017-performance-budgets-lighthouse-ci.md) | Performance budgets — Core Web Vitals + Lighthouse CI gates, bundle budgets, BFF p95/p99 SLOs | accepted | `performance`, `frontend`, `backend`, `process` | 2026-04-30 |
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| [0018](0018-environment-configuration-strategy.md) | Environment configuration — Angular `environment.ts`, BFF env vars, audit pool split | accepted | `frontend`, `backend`, `infrastructure`, `process` | 2026-05-10 |
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| [0019](0019-internationalisation-angular-localize.md) | Internationalisation — `@angular/localize`, build-time per-locale bundles, `/fr` + `/en` path-based routing | accepted | `frontend`, `accessibility`, `performance`, `process` | 2026-05-11 |
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| [0020](0020-portal-admin-app.md) | `portal-admin` — dedicated SPA for portal administration, sharing the existing BFF | accepted | `frontend`, `backend`, `security`, `infrastructure`, `process` | 2026-05-11 |
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| [0021](0021-phase-2-security-baseline.md) | Phase-2 security baseline — helmet, CORS allowlist, double-submit CSRF, rate limiting, structured error envelope | accepted | `security`, `backend` | 2026-05-13 |
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