cf7/aukpad
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sec: CHANGE pbkdf2_hmac iteration from 200k to 600k and password rate limit 10 per 60 seconds #28

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Caffeine Fueled 2026-05-25 02:08:14 +02:00
parent e9d195a2ec
commit 5eeddecf7d
Signed by: cf7
GPG key ID: CA295D643074C68C
1 changed files with 44 additions and 10 deletions
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48
app.py
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@ -38,15 +38,24 @@ def get_client_ip(conn) -> str:
# Valkey/Redis client (initialized later if enabled)
redis_client = None
# In-memory rooms: {doc_id: {"text": str, "ver": int, "peers": set[WebSocket], "authed_peers": set[WebSocket], "last_access": float, "pw_hash": bytes|None, "pw_salt": bytes|None}}
# In-memory rooms: {doc_id: {"text": str, "ver": int, "peers": set[WebSocket], "authed_peers": set[WebSocket], "last_access": float, "pw_hash": bytes|None, "pw_salt": bytes|None, "pw_iter": int|None}}
rooms: dict[str, dict] = {}
# Rate limiting: {ip: [timestamp, timestamp, ...]}
rate_limits: dict[str, list] = defaultdict(list)
# Failed password attempts per IP (for auth brute-force / CPU-DoS limiting)
failed_auth_attempts: dict[str, list] = defaultdict(list)
# Connection tracking: {ip: connection_count}
connections_per_ip: dict[str, int] = defaultdict(int)
# Password hashing parameters
PBKDF2_ITERATIONS = 600_000 # OWASP 2023 recommendation for PBKDF2-SHA256
LEGACY_PBKDF2_ITERATIONS = 200_000 # backward-compat for pads hashed before the bump
MAX_AUTH_FAILURES = 10 # failed password attempts allowed per window
AUTH_FAILURE_WINDOW = 60 # seconds
def random_id(n: int = 8) -> str:
alphabet = string.ascii_lowercase + string.digits
return "".join(secrets.choice(alphabet) for _ in range(n))
@ -91,6 +100,7 @@ def save_room_data_to_cache(doc_id: str, room: dict):
"last_access": room.get("last_access", time.time()),
"pw_hash": room["pw_hash"].hex() if room.get("pw_hash") else None,
"pw_salt": room["pw_salt"].hex() if room.get("pw_salt") else None,
"pw_iter": room.get("pw_iter"),
}
redis_client.setex(f"room:{doc_id}", RETENTION_HOURS * 3600, json.dumps(data))
except Exception as e:
@ -149,6 +159,15 @@ def check_rate_limit(client_ip: str) -> bool:
rate_limits[client_ip].append(now)
return True
def check_auth_rate_limit(client_ip: str) -> bool:
now = time.time()
cutoff = now - AUTH_FAILURE_WINDOW
failed_auth_attempts[client_ip] = [t for t in failed_auth_attempts[client_ip] if t > cutoff]
return len(failed_auth_attempts[client_ip]) < MAX_AUTH_FAILURES
def record_auth_failure(client_ip: str):
failed_auth_attempts[client_ip].append(time.time())
HTML = """<!doctype html>
<meta charset="utf-8"/>
<title>aukpad</title>
@ -640,7 +659,7 @@ async def create_pad_with_content(request: Request):
doc_id = random_id()
rooms[doc_id] = {"text": text_content, "ver": 1, "peers": set(), "authed_peers": set(),
"last_access": time.time(), "pw_hash": None, "pw_salt": None}
"last_access": time.time(), "pw_hash": None, "pw_salt": None, "pw_iter": None}
# Save to cache if enabled
save_room_data_to_cache(doc_id, rooms[doc_id])
@ -658,7 +677,7 @@ def pad(doc_id: str):
return HTMLResponse(HTML)
@app.get("/{doc_id}/raw", response_class=PlainTextResponse)
def get_raw_pad_content(doc_id: str, pw: str = ""):
def get_raw_pad_content(doc_id: str, request: Request, pw: str = ""):
if not is_valid_doc_id(doc_id):
raise HTTPException(status_code=400, detail="Invalid pad ID")
# Load room into memory if needed
@ -673,6 +692,7 @@ def get_raw_pad_content(doc_id: str, pw: str = ""):
"last_access": time.time(),
"pw_hash": cached_data.get("pw_hash"),
"pw_salt": cached_data.get("pw_salt"),
"pw_iter": cached_data.get("pw_iter"),
}
if doc_id not in rooms:
@ -684,8 +704,13 @@ def get_raw_pad_content(doc_id: str, pw: str = ""):
if room.get("pw_hash"):
if not pw:
raise HTTPException(status_code=403, detail="This pad is password protected. Use ?pw=<password>")
candidate = hashlib.pbkdf2_hmac("sha256", pw.encode(), room["pw_salt"], 200_000)
client_ip = get_client_ip(request)
if not check_auth_rate_limit(client_ip):
raise HTTPException(status_code=429, detail="Too many failed attempts. Try again later.")
iters = room.get("pw_iter") or LEGACY_PBKDF2_ITERATIONS
candidate = hashlib.pbkdf2_hmac("sha256", pw.encode(), room["pw_salt"], iters)
if candidate != room["pw_hash"]:
record_auth_failure(client_ip)
raise HTTPException(status_code=403, detail="Wrong password")
update_room_access_time(doc_id)
@ -738,6 +763,7 @@ async def ws(doc_id: str, ws: WebSocket):
"last_access": time.time(),
"pw_hash": cached_data.get("pw_hash"),
"pw_salt": cached_data.get("pw_salt"),
"pw_iter": cached_data.get("pw_iter"),
}
# Refuse to create new rooms when at capacity
@ -747,7 +773,8 @@ async def ws(doc_id: str, ws: WebSocket):
return
room = rooms.setdefault(doc_id, {"text": "", "ver": 0, "peers": set(), "authed_peers": set(),
"last_access": time.time(), "pw_hash": None, "pw_salt": None})
"last_access": time.time(), "pw_hash": None, "pw_salt": None,
"pw_iter": None})
room["peers"].add(ws)
# Update access time
@ -783,8 +810,12 @@ async def ws(doc_id: str, ws: WebSocket):
"type": "init", "text": room["text"], "ver": room["ver"], "protected": False,
}))
else:
if not check_auth_rate_limit(client_ip):
await ws.send_text(json.dumps({"type": "error", "message": "Too many failed attempts. Try again later."}))
continue
iters = room.get("pw_iter") or LEGACY_PBKDF2_ITERATIONS
candidate = hashlib.pbkdf2_hmac(
"sha256", str(data.get("password", "")).encode(), room["pw_salt"], 200_000
"sha256", str(data.get("password", "")).encode(), room["pw_salt"], iters
)
if candidate == room["pw_hash"]:
authed = True
@ -794,6 +825,7 @@ async def ws(doc_id: str, ws: WebSocket):
"type": "init", "text": room["text"], "ver": room["ver"], "protected": True,
}))
else:
record_auth_failure(client_ip)
await ws.send_text(json.dumps({"type": "error", "message": "Wrong password"}))
continue
@ -827,11 +859,13 @@ async def ws(doc_id: str, ws: WebSocket):
pw = str(data.get("password", ""))
if pw:
salt = os.urandom(16)
room["pw_hash"] = hashlib.pbkdf2_hmac("sha256", pw.encode(), salt, 200_000)
room["pw_hash"] = hashlib.pbkdf2_hmac("sha256", pw.encode(), salt, PBKDF2_ITERATIONS)
room["pw_salt"] = salt
room["pw_iter"] = PBKDF2_ITERATIONS
else:
room["pw_hash"] = None
room["pw_salt"] = None
room["pw_iter"] = None
save_room_data_to_cache(doc_id, room)
await _broadcast(doc_id, {"type": "protected_changed", "protected": room["pw_hash"] is not None})