davide/plm-lottery
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases Wiki Activity

Make X-Forwarded-For trustworthy instead of attacker-controlled (B-54)

Browse Source 
client_ip() read the first element of X-Forwarded-For, which is correct only if
the proxy replaces the header. Caddy appends the peer address to whatever the
client sent, so element 0 was whatever the caller claimed: rotating a fake value
per request minted a fresh identity every time and walked straight through the
login and registration throttles (B-33) and the SSE per-IP subscriber cap
(B-38). Only the per-username login bucket, which doesn't key on the IP, still
bit.

Both halves of the audit's fix, since they hold independently:

- the Caddyfile overwrites the header with `header_up X-Forwarded-For
  {remote_host}`, so what reaches the app is the actual peer and nothing else.
  This is the one that makes the app's assumption true at the source.
- client_ip() reads the *last* hop rather than the first — the element written
  by the hop closest to us, i.e. by our own proxy. Exactly one trusted proxy
  sits in front of the app (`app` is only `expose`d on the compose network,
  never published to the host), so that element is the real peer.

An empty or comma-only header now falls back to request.client.host instead of
returning "", which was its own shared-bucket evasion.

Regression tests both sides: two requests spoofing different prefixes must key
to the same IP, and the Caddyfile must keep the header_up directive (checked by
`caddy validate`).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
davide
2026-08-03 22:14:03 +02:00
co-authored by Claude Opus 5
parent 8f3cdcb2f8
commit 907e32e9e0
6 changed files with 67 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files
CLAUDE.md
+3 -3
View File
@@ -8,7 +8,7 @@ The user communicates in Italian in chat — reply to them in Italian. Everythin
## Project status
All 10 stages of the original build order are code-complete and unit-tested — 275 tests, all under `tests/unit/` (`tests/integration/` is an empty package). Beyond them: Docker + Caddy deployment, admin dashboard (`/admin`), static test UI (`/`), pending-inclusive balance display, an SSE push channel layered over the original polling, self-service password change + admin password reset, and the reconciliation/corroboration machinery below.
All 10 stages of the original build order are code-complete and unit-tested — 278 tests, all under `tests/unit/` (`tests/integration/` is an empty package). Beyond them: Docker + Caddy deployment, admin dashboard (`/admin`), static test UI (`/`), pending-inclusive balance display, an SSE push channel layered over the original polling, self-service password change + admin password reset, and the reconciliation/corroboration machinery below.
Verified on mainnet with real money: registration + address derivation, deposit crediting (1-conf), a real 10 PLM bet (broadcast → confirmed → change credited back), and one full round cycle (close → draw on a real block hash → 70/30 payout with sat math checked against the broadcast tx → confirmation → close → next round auto-opened). **Withdrawal and the RBF bump path have never been exercised against a live broadcast** — unit-tested only.
@@ -33,7 +33,7 @@ PYTHONPATH=. python scripts/decrypt_master_key.py # ops recovery: decrypt+pr
PYTHONPATH=. python scripts/encrypt_master_key.py # ops bootstrap: import an externally-generated xprv (--overwrite to replace)
PYTHONPATH=. python scripts/electrum_smoke_test.py # manual check: connect, handshake, subscribe to headers, print the tip
python -m pytest # all 275 tests
python -m pytest # all 278 tests
python -m pytest tests/unit/test_hd.py # one file
python -m pytest tests/unit/test_hd.py::test_derivation_is_deterministic # one test
```
@@ -55,7 +55,7 @@ docker compose down
`SITE_ADDRESS` unset → `localhost`, Caddy issues a self-signed cert from its internal CA (browser warning on first visit is expected; `curl -k`). `SITE_ADDRESS=lottery.example.com docker compose up -d` → real Let's Encrypt cert, automatically renewed (needs DNS pointing here and ports 80+443 reachable).
The `Caddyfile` sends baseline security headers — HSTS, `X-Content-Type-Options: nosniff`, `X-Frame-Options: DENY`, `Referrer-Policy`, and a CSP scoped to `default-src 'self'` plus the Google Fonts `@import` in `style.css`/`admin.css`. `script-src`/`style-src` need `'unsafe-inline'` because both SPAs use inline `onclick` handlers and `style=""` attributes throughout — removing those is a separate, larger refactor, not a header change. `restart: unless-stopped` on `app` means a mid-round crash auto-restarts: `closing` and `paying_out` resume on their own, `drawing` does not (see Known gaps).
The `Caddyfile` sends baseline security headers — HSTS, `X-Content-Type-Options: nosniff`, `X-Frame-Options: DENY`, `Referrer-Policy`, and a CSP scoped to `default-src 'self'` plus the Google Fonts `@import` in `style.css`/`admin.css`. It also overwrites `X-Forwarded-For` with the real peer (`header_up X-Forwarded-For {remote_host}`, B-54) — Caddy otherwise *appends* to whatever the client sent, which made every IP-keyed control (the B-33 throttles, B-38's SSE cap) bypassable; `app/api/client_ip.py` independently reads the *last* hop, so either half closes it. `script-src`/`style-src` need `'unsafe-inline'` because both SPAs use inline `onclick` handlers and `style=""` attributes throughout — removing those is a separate, larger refactor, not a header change. `restart: unless-stopped` on `app` means a mid-round crash auto-restarts: `closing` and `paying_out` resume on their own, `drawing` does not (see Known gaps).
## Tech stack