SA-005 addressed by updateing ratelimiting

backend/app/services/login_throttle.py

@@ -0,0 +1,64 @@
+## Copyright © 2026 Olaf Kolkman
+## SPDX-License-Identifier: GPL-3.0-or-later
+
+from datetime import datetime, timedelta, timezone
+from hashlib import sha256
+import json
+
+from backend.app.database import get_connection
+
+MAX_FAILURES = 5
+FAILURE_WINDOW = timedelta(minutes=15)
+LOCKOUT_DURATION = timedelta(minutes=2)
+
+
+def _setting_name(ip_address: str, email: str) -> str:
+    key = sha256(f'{ip_address}\0{email.casefold()}'.encode('utf-8')).hexdigest()
+    return f'login_rate:{key}'
+
+
+def _read_rate(setting_name: str) -> dict:
+    with get_connection() as conn:
+        row = conn.execute('SELECT value FROM app_settings WHERE name = ?', (setting_name,)).fetchone()
+    if not row:
+        return {}
+    try:
+        return json.loads(row['value'])
+    except (TypeError, json.JSONDecodeError):
+        return {}
+
+
+def check_login_allowed(ip_address: str, email: str) -> int | None:
+    rate = _read_rate(_setting_name(ip_address, email))
+    now = datetime.now(timezone.utc)
+    locked_until = datetime.fromisoformat(rate['locked_until']) if rate.get('locked_until') else None
+    if locked_until and locked_until > now:
+        return int((locked_until - now).total_seconds()) + 1
+    return None
+
+
+def record_login_failure(ip_address: str, email: str) -> None:
+    setting_name = _setting_name(ip_address, email)
+    now = datetime.now(timezone.utc)
+    rate = _read_rate(setting_name)
+    first_failure = datetime.fromisoformat(rate['first_failure']) if rate.get('first_failure') else now
+    if now - first_failure >= FAILURE_WINDOW:
+        rate = {}
+        first_failure = now
+    failures = int(rate.get('failures', 0)) + 1
+    updated = {'failures': failures, 'first_failure': first_failure.isoformat()}
+    if failures >= MAX_FAILURES:
+        updated['locked_until'] = (now + LOCKOUT_DURATION).isoformat()
+    with get_connection() as conn:
+        conn.execute(
+            '''INSERT INTO app_settings (name, value, updated_at) VALUES (?, ?, CURRENT_TIMESTAMP)
+               ON CONFLICT(name) DO UPDATE SET value = excluded.value, updated_at = CURRENT_TIMESTAMP''',
+            (setting_name, json.dumps(updated)),
+        )
+        conn.commit()
+
+
+def clear_login_failures(ip_address: str, email: str) -> None:
+    with get_connection() as conn:
+        conn.execute('DELETE FROM app_settings WHERE name = ?', (_setting_name(ip_address, email),))
+        conn.commit()