webshell交易原理_webshell扫描工具

webshell交易原理_webshell扫描工具 前言最近工作中需要开发前端 *** 作远程虚拟机的功能，简称 WebShell。

基于当前的技术栈为 react+django，调研了一会发现大部分的后端实现都是 django+channels 来实现 websocket 服务。

大致看了下觉得这不够有趣，翻了翻 django 的官方文档发现 django 原生是不支持 websocket 的，但 django3 之后支持了 asgi 协议可以自己实现 websocket 服务。

于是选定 gunicorn+uvicorn+asgi+websocket+django3.2+paramiko 来实现 WebShell。

实现 websocket 服务使用 django 自带的脚手架生成的项目会自动生成 asgi.py 和 wsgi.py 两个文件，普通应用大部分用的都是 wsgi.py 配合 nginx 部署线上服务。

这次主要使用 asgi.py 实现 websocket 服务的思路大致网上搜一下就能找到，主要就是实现connect/send/receive/disconnect 这个几个动作的处理方法。

这里 How to Add Websockets to a Django App without Extra Dependencies(https://jaydenwindle.com/writing/django-websockets-zero-dependencies/) 就是一个很好的实例，但过于简单……思路 # asgi.py import os from django.core.asgi import get_asgi_application from websocket_app.websocket import websocket_application os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'websocket_app.settings') django_application = get_asgi_application() async def application(scope, receive, send): if scope['type'] == 'http': await django_application(scope, receive, send) elif scope['type'] == 'websocket': await websocket_application(scope, receive, send) else: raise NotImplementedError(f"Unknown scope type {scope['type']}") # websocket.py async def websocket_application(scope, receive, send): pass # websocket.py async def websocket_application(scope, receive, send): while True: event = await receive() if event['type'] == 'websocket.connect': await send({ 'type': 'websocket.accept' }) if event['type'] == 'websocket.disconnect': break if event['type'] == 'websocket.receive': if event['text'] == 'ping': await send({ 'type': 'websocket.send', 'text': 'pong!' })实现上面的代码提供了思路，比较完整的可以参考这里 websockets-in-django-3-1 (https://aliashkevich.com/websockets-in-django-3-1/) 基本可以复用了。

其中最核心的实现部分我放下面： class WebSocket: def __init__(self, scope, receive, send): self._scope = scope self._receive = receive self._send = send self._client_state = State.CONNECTING self._app_state = State.CONNECTING @property def headers(self): return Headers(self._scope) @property def scheme(self): return self._scope["scheme"] @property def path(self): return self._scope["path"] @property def query_params(self): return QueryParams(self._scope["query_string"].decode()) @property def query_string(self) -> str: return self._scope["query_string"] @property def scope(self): return self._scope async def accept(self, subprotocol: str = None): """Accept connection. :param subprotocol: The subprotocol the server wishes to accept. :type subprotocol: str, optional """ if self._client_state == State.CONNECTING: await self.receive() await self.send({"type": SendEvent.ACCEPT, "subprotocol": subprotocol}) async def close(self, code: int = 1000): await self.send({"type": SendEvent.CLOSE, "code": code}) async def send(self, message: t.Mapping): if self._app_state == State.DISCONNECTED: raise RuntimeError("WebSocket is disconnected.") if self._app_state == State.CONNECTING: assert message["type"] in {SendEvent.ACCEPT, SendEvent.CLOSE}, ( 'Could not write event "%s" into socket in connecting state.' % message["type"] ) if message["type"] == SendEvent.CLOSE: self._app_state = State.DISCONNECTED else: self._app_state = State.CONNECTED elif self._app_state == State.CONNECTED: assert message["type"] in {SendEvent.SEND, SendEvent.CLOSE}, ( 'Connected socket can send "%s" and "%s" events, not "%s"' % (SendEvent.SEND, SendEvent.CLOSE, message["type"]) ) if message["type"] == SendEvent.CLOSE: self._app_state = State.DISCONNECTED await self._send(message) async def receive(self): if self._client_state == State.DISCONNECTED: raise RuntimeError("WebSocket is disconnected.") message = await self._receive() if self._client_state == State.CONNECTING: assert message["type"] == ReceiveEvent.CONNECT, ( 'WebSocket is in connecting state but received "%s" event' % message["type"] ) self._client_state = State.CONNECTED elif self._client_state == State.CONNECTED: assert message["type"] in {ReceiveEvent.RECEIVE, ReceiveEvent.DISCONNECT}, ( 'WebSocket is connected but received invalid event "%s".' % message["type"] ) if message["type"] == ReceiveEvent.DISCONNECT: self._client_state = State.DISCONNECTED return message缝合怪做为合格的代码搬运工，为了提高搬运效率还是要造点轮子填点坑的，如何将上面的 WebSocket 类与 paramiko 结合起来，实现从前端接受字符传递给远程主机，并同时接受返回呢？ import asyncio import traceback import paramiko from webshell.ssh import Base, RemoteSSH from webshell.connection import WebSocket class WebShell: """整理 WebSocket 和 paramiko.Channel,实现两者的数据互通""" def __init__(self, ws_session: WebSocket, ssh_session: paramiko.SSHClient = None, chanel_session: paramiko.Channel = None ): self.ws_session = ws_session self.ssh_session = ssh_session self.chanel_session = chanel_session def init_ssh(self, host=None, port=22, user="admin", passwd="admin@123"): self.ssh_session, self.chanel_session = RemoteSSH(host, port, user, passwd).session() def set_ssh(self, ssh_session, chanel_session): self.ssh_session = ssh_session self.chanel_session = chanel_session async def ready(self): await self.ws_session.accept() async def welcome(self): # 展示Linux欢迎相关内容 for i in range(2): if self.chanel_session.send_ready(): message = self.chanel_session.recv(2048).decode('utf-8') if not message: return await self.ws_session.send_text(message) async def web_to_ssh(self): # print('--------web_to_ssh------->') while True: # print('--------------->') if not self.chanel_session.active or not self.ws_session.status: return await asyncio.sleep(0.01) shell = await self.ws_session.receive_text() # print('-------shell-------->', shell) if self.chanel_session.active and self.chanel_session.send_ready(): self.chanel_session.send(bytes(shell, 'utf-8')) # print('--------------->', "end") async def ssh_to_web(self): # print('<--------ssh_to_web-----------') while True: # print('<-------------------') if not self.chanel_session.active: await self.ws_session.send_text('ssh closed') return if not self.ws_session.status: return await asyncio.sleep(0.01) if self.chanel_session.recv_ready(): message = self.chanel_session.recv(2048).decode('utf-8') # print('<---------message----------', message) if not len(message): continue await self.ws_session.send_text(message) # print('<-------------------', "end") async def run(self): if not self.ssh_session: raise Exception("ssh not init!") await self.ready() await asyncio.gather( self.web_to_ssh(), self.ssh_to_web() ) def clear(self): try: self.ws_session.close() except Exception: traceback.print_stack() try: self.ssh_session.close() except Exception: traceback.print_stack()前端xterm.js 完全满足，搜索下找个看着简单的就行。

export class Term extends React.Component { private terminal!: HTMLDivElement; private fitAddon = new FitAddon(); componentDidMount() { const xterm = new Terminal(); xterm.loadAddon(this.fitAddon); xterm.loadAddon(new WebLinksAddon()); // using wss for https // const socket = new WebSocket("ws://" + window.location.host + "/api/v1/ws"); const socket = new WebSocket("ws://localhost:8000/webshell/"); // socket.onclose = (event) => { // this.props.onClose(); // } socket.onopen = (event) => { xterm.loadAddon(new AttachAddon(socket)); this.fitAddon.fit(); xterm.focus(); } xterm.open(this.terminal); xterm.onResize(({ cols, rows }) => { socket.send("<RESIZE>" + cols + "," + rows) }); window.addEventListener('resize', this.onResize); } componentWillUnmount() { window.removeEventListener('resize', this.onResize); } onResize = () => { this.fitAddon.fit(); } render() { return <div className="Terminal" ref={(ref) => this.terminal = ref as HTMLDivElement}></div>; } }