security: harden alert_routes.py — auth coverage + input validation

Issues fixed:

1. [CRITICAL] /api/alert/fix unauthenticated (CWE-306)
   POST /api/alert/fix had no @check_alert_auth and was CSRF-exempt.
   Any unauthenticated caller could trigger docker restart or
   docker exec on arbitrary container names (container_name is validated
   by is_valid_container_name but restart of any valid name is still
   a DoS vector). Fix: @check_alert_auth added.

2. [HIGH] Hardcoded ALERT_WEBHOOK_PASSWORD fallback (CWE-798)
   Default 'wooo_alert_2026' exposed in source. Fix: default='',
   startup warning if unset. check_alert_auth now fail-secure:
   returns 503 if password not configured.

3. [MEDIUM] /api/alert/history and /api/alert/analyze unauthenticated
   Both endpoints expose container names, memory usage, CPU stats,
   system recommendations. Fix: @check_alert_auth added to both.

4. [MEDIUM] issue_type unvalidated in manual_fix (CWE-20)
   Any string value could be passed through to auto_fix_container.
   Fix: ALLOWED_ISSUE_TYPES frozenset — only memory/cpu variants allowed.

5. [LOW] limit parameter unbounded in get_alert_history
   Arbitrarily large limit → large list slice → memory pressure.
   Fix: clamped to [1, 200].

NOTE: L177 docker stats command (original report) is SAFE as-is —
list argv, fixed arguments, no user input. nosec B603 correctly placed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

routes/alert_routes.py

@@ -51,7 +51,13 @@ def csrf_exempt_for_alerts():
 
 # 告警 Webhook 認證
 ALERT_WEBHOOK_USER = os.getenv('ALERT_WEBHOOK_USER', 'alertmanager')
-ALERT_WEBHOOK_PASSWORD = os.getenv('ALERT_WEBHOOK_PASSWORD', 'wooo_alert_2026')
+ALERT_WEBHOOK_PASSWORD = os.getenv('ALERT_WEBHOOK_PASSWORD', '')
+
+if not ALERT_WEBHOOK_PASSWORD:
+    logger.warning(
+        '[SECURITY] ALERT_WEBHOOK_PASSWORD is not set. '
+        'All webhook requests will be rejected. Set this environment variable.'
+    )
 
 # Telegram 設定
 TELEGRAM_BOT_TOKEN = os.getenv('TELEGRAM_BOT_TOKEN', '')
@@ -66,11 +72,20 @@ AUTO_FIX_ENABLED = os.getenv('AUTO_FIX_ENABLED', 'true').lower() == 'true'
 AUTO_FIX_COOLDOWN = 300  # 同一容器 5 分鐘內不重複修復
 _last_fix_time = {}
 
+# issue_type allowlist（防止任意值傳入 auto_fix_container）
+ALLOWED_ISSUE_TYPES = frozenset({
+    'memory', 'container_memory',
+    'cpu',    'container_cpu',
+})
+
 
 def check_alert_auth(f):
-    """告警 Webhook 認證裝飾器"""
+    """告警 Webhook 認證裝飾器（fail-secure：密碼未設定時拒絕所有請求）"""
     @wraps(f)
     def decorated(*args, **kwargs):
+        # fail-secure: 若密碼未設定，拒絕一切存取
+        if not ALERT_WEBHOOK_PASSWORD:
+            return jsonify({'error': 'Server misconfiguration: auth not configured'}), 503
         auth = request.authorization
         if not auth:
             return jsonify({'error': 'Missing authentication'}), 401
@@ -384,9 +399,12 @@ def alert_webhook():
 
 
 @alert_bp.route('/api/alert/history')
+@check_alert_auth
 def get_alert_history():
-    """取得告警歷史記錄"""
+    """取得告警歷史記錄（需認證，防止系統資訊外洩）"""
     limit = request.args.get('limit', 50, type=int)
+    # 限制 limit 範圍，防止記憶體 DoS
+    limit = max(1, min(limit, 200))
     return jsonify({
         'success': True,
         'data': _alert_history[-limit:][::-1]  # 最新的在前
@@ -394,8 +412,9 @@ def get_alert_history():
 
 
 @alert_bp.route('/api/alert/analyze')
+@check_alert_auth
 def analyze_system():
-    """手動觸發系統分析"""
+    """手動觸發系統分析（需認證，防止系統資訊外洩）"""
     analysis = analyze_high_load()
     return jsonify({
         'success': True,
@@ -404,15 +423,23 @@ def analyze_system():
 
 
 @alert_bp.route('/api/alert/fix', methods=['POST'])
+@check_alert_auth
 def manual_fix():
-    """手動觸發修復"""
-    data = request.get_json()
+    """手動觸發修復（需認證 + issue_type allowlist）"""
+    data = request.get_json() or {}
     container_name = data.get('container')
     issue_type = data.get('issue_type', 'memory')
 
     if not container_name:
         return jsonify({'error': 'Missing container name'}), 400
 
+    # Security: issue_type 只允許已知有效值
+    if issue_type not in ALLOWED_ISSUE_TYPES:
+        return jsonify({
+            'error': f'Invalid issue_type: {issue_type}. '
+                     f'Allowed: {sorted(ALLOWED_ISSUE_TYPES)}'
+        }), 400
+
     result = auto_fix_container(container_name, issue_type)
     return jsonify({
         'success': result['success'],