修复关键安全漏洞(Bug #19和Bug #13)

修复的Bug:
- Bug #19: 路径遍历漏洞
- Bug #13: 浏览器上下文竞态条件

主要改进:
1. 路径遍历防护:
   - /screenshots/<filename> 端点添加is_safe_path()验证
   - /static/<path:filename> 端点添加is_safe_path()验证
   - 防止攻击者通过../等序列访问系统文件

2. 浏览器资源并发保护:
   - PlaywrightAutomation类添加_lock线程锁
   - get_iframe_safe()方法使用锁保护main_page访问
   - close()方法使用锁保护资源释放
   - _cleanup_on_exit()使用非阻塞锁避免退出死锁
   - 解决TOCTOU(Time-of-Check-Time-of-Use)竞态条件

影响:
- 防止路径遍历攻击,保护系统文件安全
- 防止多线程环境下的浏览器资源竞争
- 提升系统安全性和稳定性

受影响文件:
- app.py (路径验证)
- playwright_automation.py (线程锁)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app.py

@@ -98,11 +98,17 @@ user_accounts = {}  # {user_id: {account_id: Account对象}}
 active_tasks = {}  # {account_id: Thread对象}
 task_status = {}  # {account_id: {"user_id": x, "username": y, "status": "排队中/运行中", "detail_status": "具体状态", "browse_type": z, "start_time": t, "source": s, "progress": {...}, "is_vip": bool}}
 
+# 线程安全锁 - 修复Bug #12
+active_tasks_lock = threading.Lock()  # 保护 active_tasks 字典
+task_status_lock = threading.Lock()   # 保护 task_status 字典
+user_accounts_lock = threading.Lock() # 保护 user_accounts 字典
+
 # VIP优先级队列
 vip_task_queue = []  # VIP用户任务队列
 normal_task_queue = []  # 普通用户任务队列
 task_queue_lock = threading.Lock()
 log_cache = {}  # {user_id: [logs]} 每个用户独立的日志缓存
+log_cache_lock = threading.Lock()  # 保护 log_cache 字典
 log_cache_total_count = 0  # 全局日志总数,防止无限增长
 
 # 日志缓存限制
@@ -214,6 +220,73 @@ class Account:
         return result
 
 
+# ========== 线程安全辅助函数 - 修复Bug #12 ==========
+
+def safe_set_task(account_id, thread):
+    """线程安全地设置任务"""
+    with active_tasks_lock:
+        active_tasks[account_id] = thread
+
+def safe_get_task(account_id):
+    """线程安全地获取任务"""
+    with active_tasks_lock:
+        return active_tasks.get(account_id)
+
+def safe_remove_task(account_id):
+    """线程安全地移除任务"""
+    with active_tasks_lock:
+        return active_tasks.pop(account_id, None)
+
+def safe_set_task_status(account_id, status_dict):
+    """线程安全地设置任务状态"""
+    with task_status_lock:
+        task_status[account_id] = status_dict
+
+def safe_update_task_status(account_id, updates):
+    """线程安全地更新任务状态"""
+    with task_status_lock:
+        if account_id in task_status:
+            task_status[account_id].update(updates)
+
+def safe_get_task_status(account_id):
+    """线程安全地获取任务状态"""
+    with task_status_lock:
+        return task_status.get(account_id, {}).copy()
+
+def safe_remove_task_status(account_id):
+    """线程安全地移除任务状态"""
+    with task_status_lock:
+        return task_status.pop(account_id, None)
+
+def safe_get_all_task_status():
+    """线程安全地获取所有任务状态"""
+    with task_status_lock:
+        return {k: v.copy() for k, v in task_status.items()}
+
+def safe_add_log(user_id, log_entry):
+    """线程安全地添加日志"""
+    global log_cache_total_count
+    with log_cache_lock:
+        if user_id not in log_cache:
+            log_cache[user_id] = []
+
+        # 限制每个用户的日志数量
+        if len(log_cache[user_id]) >= MAX_LOGS_PER_USER:
+            log_cache[user_id].pop(0)
+            log_cache_total_count = max(0, log_cache_total_count - 1)
+
+        log_cache[user_id].append(log_entry)
+        log_cache_total_count += 1
+
+        # 全局日志总数限制
+        if log_cache_total_count > MAX_TOTAL_LOGS:
+            # 删除最早用户的最早日志
+            for uid in list(log_cache.keys()):
+                if log_cache[uid]:
+                    log_cache[uid].pop(0)
+                    log_cache_total_count -= 1
+                    break
+
 @login_manager.user_loader
 def load_user(user_id):
     """Flask-Login 用户加载"""
@@ -2078,6 +2151,10 @@ def serve_screenshot(filename):
     if not filename.startswith(username_prefix + '_'):
         return jsonify({"error": "无权访问"}), 403
 
+    # 防止路径遍历攻击 (Bug #19 fix)
+    if not is_safe_path(SCREENSHOTS_DIR, filename):
+        return jsonify({"error": "非法路径"}), 403
+
     return send_from_directory(SCREENSHOTS_DIR, filename)
 
 
@@ -2177,6 +2254,10 @@ def handle_disconnect():
 @app.route('/static/<path:filename>')
 def serve_static(filename):
     """提供静态文件访问"""
+    # 防止路径遍历攻击 (Bug #19 fix)
+    if not is_safe_path('static', filename):
+        return jsonify({"error": "非法路径"}), 403
+
     response = send_from_directory('static', filename)
     # 禁用缓存，强制浏览器每次都重新加载
     response.headers['Cache-Control'] = 'no-store, no-cache, must-revalidate, max-age=0'