plm-lottery/BUGS.md

Known bugs

A second full-codebase audit on 2026-07-27 found 25 further issues (4 critical, 6 high, 7 medium, 8 low), listed below as B-33 … B-49. B-25 through B-35 are fixed (see "Previously fixed" below) — no Critical-severity finding remains open; the other 14 are High/Medium/Low. The 139-test suite was green at the time of the audit, so none of these were caught by existing coverage — every fix lands with a regression test (the eleven fixes so far brought the suite from 139 to 198).

The recurring pattern across the open findings is worth stating once: the code is rigorous about the failure modes that have actually been hit, and silent about the ones that have not. The payout phase is now fully recoverable; the "drawing" phase (waiting on a block) still has no equivalent resume-after-restart or stall visibility (B-36).

For limitations that are accepted by design rather than bugs (single-shared-token admin auth, single-process assumptions, no user-facing history, etc.), see "Known gaps / TODO" in CLAUDE.md.

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Medium

B-36 — _wait_for_next_block waits forever, with no timeout and no visibility

rounds/scheduler.py:158-161 loops until a higher block arrives. No timeout, no log, no audit entry. If the connection dies in a way that stops the tip advancing, the round sits in drawing indefinitely and the admin panel shows nothing at all — just a frozen state with no explanation.

Proposed fix. Log progress periodically while waiting, and past a threshold (a few multiples of the 120s block time) write a draw_stalled audit entry so it surfaces in /admin. Surface the wait in GET /rounds/current too (it already returns chain_tip_height; draw_waiting_since would make the stall self-evident to users).

B-37 — Displayed balance and spendable balance diverge, and the error does not explain it

After a bet the change is unconfirmed, so cached_balance_sats ≈ 0 while the UI shows pending_balance_sats (the real figure). A withdrawal attempted right after validates against confirmed UTXOs (withdrawals/service.py:54-60) and answers insufficient_balance.

The user sees "1.000 PLM" on screen and is told they have no funds. The mechanism is a documented design decision, but the error does not distinguish "you don't have the money" from "your money is waiting to confirm" — two very different situations for whoever reads it.

Proposed fix. A distinct error code (e.g. balance_pending_confirmation) raised when the requested amount is covered by pending_balance_sats but not by the confirmed balance, carrying the pending amount in params, plus its error.* entry in all 7 languages. The withdrawal form should also cap/hint the max against the confirmed balance rather than the displayed one.

B-38 — The 500-subscriber SSE cap is a zero-cost DoS of the realtime feature

GET /rounds/stream requires no authentication and each connection takes a slot on a global counter (rounds/events.py:33-38). Anyone opening 500 connections degrades every real user to polling. The comment describes it as a defensive cap; it is in fact the vector, not the defence.

Proposed fix. Cap per client IP (and, once available, per authenticated user) rather than globally, and evict the oldest idle subscriber instead of refusing new ones. The reverse proxy is the right place for the connection-count limit — Caddy can enforce it before the request reaches the app.

B-39 — SQLite with no WAL, no busy_timeout, and five concurrent writer tasks

db/base.py:6 calls create_async_engine(settings.database_url) with no connect_args, and there is no PRAGMA anywhere in the repo (verified by grep). Without journal_mode=WAL readers block writers, and the concurrent writers are five background tasks plus every HTTP handler. database is locked under load is realistic, and nothing handles it.

Proposed fix. Set journal_mode=WAL, synchronous=NORMAL and a busy_timeout of a few seconds on connect (a connect event listener on the engine, applied only for the SQLite dialect), and retry OperationalError: database is locked in the background loops. Longer term this is an argument for PostgreSQL, which the single-process constraints in CLAUDE.md also point at.

B-40 — bump_fee holds a DB session open across N network calls

tx/broadcast.py:80 issues one get_transaction per input (up to 15s each) and then a broadcast, all with the session open. This is precisely the pattern B-18 removed from _trigger_payout via its three-phase structure; it survives here.

Side note in the same function: _prevout_amount does round(value_coins * 100_000_000) on a float from the server — acceptable at these magnitudes, but it is floating-point money arithmetic in a codebase that is otherwise strictly integer-satoshi.

Proposed fix. Restructure into the same three phases: read what is needed and close the session, do the chain work, then reopen to persist. For the float: prefer the raw (non-verbose) transaction and parse the output value as an integer with embit, which is what reconcile.py:_release_inputs already does for inputs.

B-41 — All confirmation logic depends on verbose=True, which is not universally supported

poll_once, reconcile._tx_exists_on_chain and bump_fee all call blockchain.transaction.get(txid, True). Several Electrum server implementations and versions reject the verbose flag ("verbose transactions are currently unsupported"). Falling back onto such a server means no confirmations, no reconciliation, no bumps — and the code would read that as a transport error and stay silent.

Related: reconcile.py:83 decides whether to abandon a transaction by substring-matching the error text ("missing", "not found", "no such", "unknown"). It works against ElectrumX; it is fragile as the basis for a decision that releases funds.

Proposed fix. Use blockchain.transaction.get_merkle (or the scripthash history) for confirmation and existence checks — both are portable and give the confirming height directly. Probe verbose support once at connect time and record it on the client, so an unsupported server is detected loudly at session start rather than silently mid-operation.

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Low / hygiene

B-42 — /docs exposed in production

FastAPI mounts Swagger by default, so the entire API surface — /admin included — is publicly enumerable. The README advertises it. Fix: docs_url=None, redoc_url=None, openapi_url=None in production (env-gated), or place them behind require_admin.

B-43 — No HTTP security headers

The Caddyfile sets no CSP, no X-Frame-Options/frame-ancestors, and no HSTS (Caddy does not add it on its own). The JWT lives in localStorage, so any XSS exfiltrates it, and the page is iframeable. Fix: a header block in the Caddyfile with Strict-Transport-Security, X-Content-Type-Options: nosniff, Referrer-Policy and a CSP tight enough for two static pages with no external assets (default-src 'self').

B-44 — README and CLAUDE.md contradict each other

The README says to run uvicorn --reload directly and docker compose run --rm app python scripts/generate_master_key.py; CLAUDE.md says explicitly that neither is supported. Whoever opens the repo reads the README first. Fix: align the README's Quick start with the Docker-only workflow documented in CLAUDE.md and docs/setup.md.

B-45 — Unvalidated and unpaginated admin list endpoints

limit: int = 50 on /admin/rounds and /admin/audit-log has no bounds (-1 means "everything" on SQLite), and /admin/pending-transactions has no limit at all — it grows without end. Fix: Query(default=50, ge=1, le=500) on both, and the same treatment plus a status filter on the pending-transaction list.

B-46 — secrets.compare_digest on a str raises on non-ASCII input

api/routes/admin.py:27 raises TypeError — a 500 instead of a 403 — when the header contains non-ASCII characters. Fix: compare the UTF-8 encoded bytes of both sides.

B-47 — Unbounded String columns for large text

raw_tx_hex (db/models.py:146) and payload_json (:178) should be Text. It works on SQLite and PostgreSQL and breaks elsewhere. Fix: switch both to Text in a migration.

B-48 — No cap on input count in select_utxos

A user with hundreds of small UTXOs builds a huge transaction whose fee — deducted from the bet amount — materially erodes their contribution to the pool, and it can exceed standardness limits. Fix: cap the selected inputs (e.g. 50) and fail with a translatable error suggesting a consolidation, or consolidate the address automatically when the count crosses a threshold.

B-49 — Rollback paths do not publish an SSE update

bets/service.py:_release_failed_bet and withdrawals/service.py:_release_failed_withdrawal restore the balance without calling broadcaster.publish(), so dashboards only find out on their next poll. Fix: one broadcaster.publish() at the end of each, as every other state-changing path already does.

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Previously fixed

• B-25 — the payout had no two-phase write, unlike bets and withdrawals
• B-26 — a payout failure or a process restart could wedge a round in paying_out forever
• B-27 — an RBF bump reset the reconciler's own abandon clock, so a repeatedly-bumped tx was never abandoned
• B-28 — a hostile Electrum server (or a MITM) could single-handedly pick the round's winner
• B-29 — a UTXO absent from one server's listunspent was marked spent immediately, irreversibly, on a single unauthenticated reply
• B-30 — a lost scripthash subscription meant a user's deposits were never credited, with no periodic safety net
• B-31 — resubscribing on reconnect ran serially before anything else started, freezing the chain tip (and so an in-flight draw) for the whole sweep
• B-32 — an RBF bump could retry forever below BIP125's relay-mandated minimum fee delta, with no ceiling on the fee rate either
• B-33 — POST /auth/login had no rate limiting, so a password could be brute-forced against an enumerable username list
• B-34 — password change/reset didn't invalidate already-issued JWTs, so a stolen token survived a change meant to lock it out
• B-35 — API timestamps round-tripped as naive datetimes, so the frontend parsed them as local time instead of UTC

See git history for the fix-by-fix breakdown (commits f13f685, 50a43ae, 933760e, and the B-28/B-29/B-30/B-31/B-32/B-33/B-34/B-35 fixes). Suite grew from 139 to 198 tests over the eleven.

A full-codebase audit on 2026-07-26 (commit d4e0974) found 24 bugs across every Python module under app/, both static frontends, and the Docker/Caddy deployment — 5 critical, 7 high, 7 medium, 5 low. All 24 were fixed and verified against the current code on 2026-07-27; the fixes are covered by the regression suite (grew from 79 to 139 tests) and five of them were additionally confirmed against a real mainnet deployment (see git history between fb734bb (documenting the findings) and 845ba98 (recording the audit outcome) for the fix-by-fix breakdown — each commit message names the bugs it closes and where their tests live).