Add login lockout and encrypt Player.totp_secret/auth_token at rest

Per-username lockout (5 failed TOTP attempts / 5 min) stops account-targeted
brute force regardless of source IP. Player.totp_secret is now Fernet-
encrypted (ENCRYPTION_KEY env, db/crypto.py) instead of stored in plaintext,
and auth_token is stored as a SHA-256 hash rather than the raw session token.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CLAUDE.md

@@ -51,8 +51,9 @@ Serialization: `Card.JSONEncoder` flattens a `Card` to `{color, value}` name str
 Async SQLAlchemy 2.0, independent of Socket.IO (mirrors how the engine is kept clean).
 
 - **`db/db.py`** — async `engine` + `async_sessionmaker`, declarative `Base`, and `init_db()` (`create_all`). Connection string from env **`DATABASE_URL`** (default `sqlite+aiosqlite:///bridzik.db`; Docker sets PostgreSQL via `asyncpg`). There are **no migrations** — `create_all` only adds new tables, so a changed column needs a fresh DB.
+- **`db/crypto.py`** — encryption/hashing for sensitive `Player` columns. `encrypt`/`decrypt` (Fernet, key from env **`ENCRYPTION_KEY`** — must stay stable, losing it locks out every account) for `totp_secret`; `hash_token` (SHA-256, one-way) for `auth_token`.
 - **`db/models.py`** — 3 tables:
-  - **`Player`** — account + auth: `username` (unique login), `totp_secret`, `totp_last_step` (TOTP replay guard), `auth_token` (session token for reconnect).
+  - **`Player`** — account + auth: `username` (unique login), `totp_secret` (Fernet-encrypted at rest via `db/crypto.py`), `totp_last_step` (TOTP replay guard), `auth_token` (session token for reconnect, stored as a SHA-256 hash, not plaintext).
   - **`Game`** — one match: `id` (gid), 4 `playerN_id` seats, `name`, `series`/`round` (current position, used for restore), `created_at`, `ended_at`.
   - **`Guess`** — one player's bid+result in a round: `series_number`, `round_number`, `guess`, `points`. `won` is derived (`points > 0`). Unique on (game, series, round, player) → idempotent writes.
 

api/auth.py

@@ -6,16 +6,25 @@ Hodnoty sa overuju cez pyotp; replay sa bloku pomocou Player.totp_last_step.
 
 import secrets
 import time
+from collections import defaultdict
 
 import pyotp
 from sqlalchemy import select
 
+from db import crypto
 from db.db import async_session
 from db.models import Player
 
 ISSUER = "Bridžik"
 TOTP_PERIOD = 30  # sekund -- default pyotp
 
+# Lockout na neuspesne prihlasovacie pokusy, per username, len v pamati
+# procesu (rovnaky pattern ako games/sessions/accounts v api/__init__.py --
+# proces je jediny, ziadny Redis).
+_LOGIN_ATTEMPT_LIMIT = 5
+_LOGIN_ATTEMPT_WINDOW = 300  # sekund
+_failed_attempts: dict[str, list[float]] = defaultdict(list)
+
 
 class AuthError(Exception):
     """Chyba prihlasenia/registracie (slovenska sprava pre klienta)."""
@@ -25,6 +34,25 @@ def _new_token() -> str:
     return secrets.token_urlsafe(48)
 
 
+def _check_lockout(username: str) -> None:
+    cutoff = time.monotonic() - _LOGIN_ATTEMPT_WINDOW
+    attempts = [t for t in _failed_attempts.get(username, []) if t > cutoff]
+    if attempts:
+        _failed_attempts[username] = attempts
+    else:
+        _failed_attempts.pop(username, None)
+    if len(attempts) >= _LOGIN_ATTEMPT_LIMIT:
+        raise AuthError("Príliš veľa neúspešných pokusov. Skúste to znova o pár minút.")
+
+
+def _register_failure(username: str) -> None:
+    _failed_attempts[username].append(time.monotonic())
+
+
+def _clear_failures(username: str) -> None:
+    _failed_attempts.pop(username, None)
+
+
 def _current_step() -> int:
     return int(time.time()) // TOTP_PERIOD
 
@@ -34,7 +62,7 @@ def _verify_code(player: Player, code: str) -> None:
 
     Akceptuje +-1 casovy krok (tolerancia hodin) a odmietne uz pouzity krok.
     """
-    totp = pyotp.TOTP(player.totp_secret)
+    totp = pyotp.TOTP(crypto.decrypt(player.totp_secret))
     current = _current_step()
     for step in (current - 1, current, current + 1):
         if step <= player.totp_last_step:
@@ -57,7 +85,7 @@ async def register_account(username: str) -> dict:
         )
         if existing is not None:
             raise AuthError("Toto meno je už obsadené.")
-        session.add(Player(username=username, totp_secret=secret))
+        session.add(Player(username=username, totp_secret=crypto.encrypt(secret)))
         await session.commit()
     otpauth_uri = pyotp.TOTP(secret).provisioning_uri(name=username, issuer_name=ISSUER)
     return {"username": username, "secret": secret, "otpauth_uri": otpauth_uri}
@@ -74,15 +102,21 @@ async def login(username: str, code: str) -> dict:
 
 
 async def _verify_and_issue_token(username: str, code: str) -> dict:
+    username = (username or "").strip()
+    _check_lockout(username)
     async with async_session() as session:
-        player = await session.scalar(
-            select(Player).where(Player.username == (username or "").strip())
-        )
+        player = await session.scalar(select(Player).where(Player.username == username))
         if player is None:
+            _register_failure(username)
             raise AuthError("Účet neexistuje.")
-        _verify_code(player, (code or "").strip())
+        try:
+            _verify_code(player, (code or "").strip())
+        except AuthError:
+            _register_failure(username)
+            raise
+        _clear_failures(username)
         token = _new_token()
-        player.auth_token = token
+        player.auth_token = crypto.hash_token(token)
         await session.commit()
         return {"player_id": player.id, "username": player.username, "token": token}
 
@@ -93,7 +127,7 @@ async def player_by_token(token: str) -> dict | None:
         return None
     async with async_session() as session:
         player = await session.scalar(
-            select(Player).where(Player.auth_token == token)
+            select(Player).where(Player.auth_token == crypto.hash_token(token))
         )
         if player is None:
             return None

db/crypto.py

@@ -0,0 +1,42 @@
+"""Sifrovanie/hashovanie citlivych stlpcov (Player.totp_secret, Player.auth_token).
+
+totp_secret sa musi dat spatne desifrovat (treba ho na vygenerovanie/overenie
+TOTP kodu), preto Fernet -- symetricke sifrovanie s klucom z env ENCRYPTION_KEY.
+auth_token sa iba porovnava, nikdy nepotrebujeme povodnu hodnotu spat, preto
+staci jednosmerny SHA-256 hash (token ma 384 bitov entropie z
+secrets.token_urlsafe(48) v api/auth.py, takze netreba salt/pepper).
+"""
+
+import hashlib
+import os
+
+from cryptography.fernet import Fernet, InvalidToken
+
+_ENV_VAR = "ENCRYPTION_KEY"
+
+
+def _fernet() -> Fernet:
+    key = os.environ.get(_ENV_VAR)
+    if not key:
+        raise RuntimeError(
+            f"{_ENV_VAR} nie je nastaveny. Vygeneruj ho pomocou:\n"
+            '  python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"\n'
+            "a nastav ako env premennu (drz ho stabilny -- zmena znamena, "
+            "ze existujuce totp_secret sa uz nedaju desifrovat)."
+        )
+    return Fernet(key.encode())
+
+
+def encrypt(plaintext: str) -> str:
+    return _fernet().encrypt(plaintext.encode()).decode()
+
+
+def decrypt(ciphertext: str) -> str:
+    try:
+        return _fernet().decrypt(ciphertext.encode()).decode()
+    except InvalidToken as exc:
+        raise ValueError("Neplatny alebo poskodeny sifrovany udaj.") from exc
+
+
+def hash_token(token: str) -> str:
+    return hashlib.sha256(token.encode()).hexdigest()

db/models.py

@@ -20,10 +20,12 @@ class Player(Base):
 
     id: Mapped[int] = mapped_column(primary_key=True)
     username: Mapped[str] = mapped_column(String(40), unique=True, index=True)
-    totp_secret: Mapped[str] = mapped_column(String(32))
+    # Sifrovany cez db/crypto.py (Fernet) -- nikdy neuklada plaintext secret.
+    totp_secret: Mapped[str] = mapped_column(String(255))
     # Posledny pouzity TOTP casovy krok -- ochrana proti replay v ramci okna.
     totp_last_step: Mapped[int] = mapped_column(Integer, default=0)
     # Session token pre auto-reconnect (poslany v Socket.IO `auth`).
+    # Uklada sa SHA-256 hash (db/crypto.hash_token), nie surovy token.
     auth_token: Mapped[str | None] = mapped_column(
         String(64), unique=True, nullable=True
     )

docker-compose.yaml

@@ -22,6 +22,9 @@ services:
       DATABASE_URL: postgresql+asyncpg://bridzik:bridzik@db:5432/bridzik
       # Shared secret for the self-hosted /api/admin/* stats endpoints.
       ADMIN_TOKEN: tajneheslo
+      # Dev-only Fernet key encrypting Player.totp_secret -- fine to hardcode
+      # here since the dev DB is disposable (docker-compose down -v).
+      ENCRYPTION_KEY: FAMD5i_Pc-Ursu_Bi49ZYMN2ehhfBkjjehxTOFvNrBU=
       # Optional: IP -> country for /api/track. Drop a .mmdb file (GeoLite2 or
       # a DB-IP/IP2Location Lite equivalent) at ./geoip/ -- it's already inside
       # the ./:/app bind mount below, no extra volume entry needed. Missing

requirements.txt

@@ -8,6 +8,7 @@ SQLAlchemy[asyncio]>=2.0
 aiosqlite>=0.20      # dev / default DATABASE_URL
 asyncpg>=0.29        # production (PostgreSQL)
 pyotp>=2.9           # TOTP login
+cryptography>=42     # Fernet encryption for Player.totp_secret at rest
 user-agents>=2.2     # parse User-Agent for /track (self-hosted analytics)
 geoip2>=4.8           # resolve IP -> country from a local .mmdb file (no external calls)
 

tests/test_history.py

@@ -12,14 +12,21 @@ import unittest
 import uuid
 from types import SimpleNamespace
 
-# Nastav DB PRED importom db/api modulov -- engine sa vytvara pri importe.
+# Nastav DB/ENCRYPTION_KEY PRED importom db/api modulov -- engine sa vytvara pri importe.
 _DB_FILE = os.path.join(tempfile.gettempdir(), f"bridzik_test_{uuid.uuid4().hex}.db")
 os.environ["DATABASE_URL"] = "sqlite+aiosqlite:///" + _DB_FILE.replace("\\", "/")
 
+from cryptography.fernet import Fernet  # noqa: E402
+
+os.environ.setdefault("ENCRYPTION_KEY", Fernet.generate_key().decode())
+
 import pyotp  # noqa: E402
+from sqlalchemy import select  # noqa: E402
 
 from api import auth, history  # noqa: E402
-from db.db import init_db  # noqa: E402
+from db import crypto  # noqa: E402
+from db.db import async_session, init_db  # noqa: E402
+from db.models import Player  # noqa: E402
 
 
 def run(coro):
@@ -76,6 +83,32 @@ class HistoryCase(unittest.TestCase):
         with self.assertRaises(auth.AuthError):
             run(auth.login(username, "000000"))
 
+    def test_login_lockout_after_repeated_failures(self):
+        username = "bob_" + uuid.uuid4().hex[:6]
+        data = run(auth.register_account(username))
+
+        for _ in range(auth._LOGIN_ATTEMPT_LIMIT):
+            with self.assertRaises(auth.AuthError):
+                run(auth.login(username, "000000"))
+
+        # Lockout odmietne aj spravny kod, kym neubehne okno
+        code = pyotp.TOTP(data["secret"]).now()
+        with self.assertRaises(auth.AuthError):
+            run(auth.login(username, code))
+
+    def test_successful_login_clears_failed_attempts(self):
+        username = "carol_" + uuid.uuid4().hex[:6]
+        data = run(auth.register_account(username))
+
+        for _ in range(auth._LOGIN_ATTEMPT_LIMIT - 1):
+            with self.assertRaises(auth.AuthError):
+                run(auth.login(username, "000000"))
+
+        code = pyotp.TOTP(data["secret"]).now()
+        ident = run(auth.login(username, code))
+        self.assertEqual(ident["username"], username)
+        self.assertNotIn(username, auth._failed_attempts)
+
     def test_record_rounds_and_idempotency(self):
         ids = self._make_players()
         gid = str(uuid.uuid4())
@@ -191,6 +224,55 @@ class HistoryCase(unittest.TestCase):
         self.assertEqual(mine["my_points"], 12)
         self.assertEqual(len(mine["players"]), 4)
 
+    def test_totp_secret_stored_encrypted_not_plaintext(self):
+        username = "dave_" + uuid.uuid4().hex[:6]
+        data = run(auth.register_account(username))
+
+        async def _raw_secret():
+            async with async_session() as session:
+                return await session.scalar(
+                    select(Player.totp_secret).where(Player.username == username)
+                )
+
+        stored = run(_raw_secret())
+        self.assertNotEqual(stored, data["secret"])
+        self.assertEqual(crypto.decrypt(stored), data["secret"])
+
+    def test_auth_token_stored_hashed_not_plaintext(self):
+        username = "erin_" + uuid.uuid4().hex[:6]
+        data = run(auth.register_account(username))
+        ident = run(auth.login(username, pyotp.TOTP(data["secret"]).now()))
+
+        async def _raw_token():
+            async with async_session() as session:
+                return await session.scalar(
+                    select(Player.auth_token).where(Player.username == username)
+                )
+
+        stored = run(_raw_token())
+        self.assertNotEqual(stored, ident["token"])
+        self.assertEqual(stored, crypto.hash_token(ident["token"]))
+
+
+class CryptoCase(unittest.TestCase):
+    def test_encrypt_decrypt_roundtrip(self):
+        secret = "JBSWY3DPEHPK3PXP"
+        ciphertext = crypto.encrypt(secret)
+        self.assertNotEqual(ciphertext, secret)
+        self.assertEqual(crypto.decrypt(ciphertext), secret)
+
+    def test_hash_token_is_deterministic_and_distinct(self):
+        self.assertEqual(crypto.hash_token("abc"), crypto.hash_token("abc"))
+        self.assertNotEqual(crypto.hash_token("abc"), crypto.hash_token("abd"))
+
+    def test_missing_key_raises(self):
+        saved = os.environ.pop("ENCRYPTION_KEY")
+        try:
+            with self.assertRaises(RuntimeError):
+                crypto.encrypt("x")
+        finally:
+            os.environ["ENCRYPTION_KEY"] = saved
+
 
 def tearDownModule():
     from db.db import engine