SSH/SFTP connection via a SOCKS5 proxy

Hi, thanks so much for the library.

Apologies if what I’m asking has been answered elsewhere. I’ve read through the docs and searched issues, but cannot find an answer to my question.

I’m trying to connect to an SFTP server via a SOCKS5 proxy (the client is running on heroku so needs to use a proxy like this to connect to a server which needs a static IP to whitelist).

I’m wondering if this is something asyncssh is able to do?

The only mention I can find of something related is forward_socks but that seems to be related to creating a socks proxy, not connecting through one.

---

To make the question more concrete, here’s an example using paramiko and socks of what I’m trying to do with asyncssh:

import paramiko
import socks


def with_paramiko():
    sock = socks.socksocket()

    sock.set_proxy(
        proxy_type=socks.SOCKS5,
        addr=proxy_host,
        port=proxy_port,
        username=proxy_username,
        password=proxy_password,
    )

    sock.connect((server_host, 22))

    transport = paramiko.Transport(sock)
    transport.connect(username=server_username, password=server_password)
    client = paramiko.SFTPClient.from_transport(transport)
    try:
        # do lots of stuff here
        print(client.listdir('/root/'))
    finally:
        client.close()
        transport.close()

[samuelcolvin]

For anyone else coming to this, there’s a working solution 🎉:

import asyncio
import stat

import aiosocks
import asyncssh
from asyncssh import SFTPClient

proxy_host = '...'
proxy_port = 123
proxy_username = '...'
proxy_password = '...'

server_host = '...'
server_port = 22
server_username = '...'
server_password = '...'


class SocksClientConnection:
    @staticmethod
    async def create_connection(session_factory, host, port):
        socks5_addr = aiosocks.Socks5Addr(proxy_host, proxy_port)
        socks5_auth = aiosocks.Socks5Auth(proxy_username, proxy_password)
        return await aiosocks.create_connection(
            session_factory, proxy=socks5_addr, proxy_auth=socks5_auth, dst=(host, port)
        )


async def tree(sftp_client: SFTPClient, path: str, indent: int = 0):
    """
    recursively print files and directories
    """
    async for file in sftp_client.scandir(path):
        if file.filename in ('.', '..'):
            continue
        file_path = f'{path}/{file.filename}'
        if stat.S_ISDIR(file.attrs.permissions):
            print(' ' * indent * 2, file_path, ':', sep='')
            await tree(sftp_client, file_path, indent + 1)
        else:
            print(' ' * indent * 2, file_path, ' (file)', sep='')
            async with sftp_client.open(file_path) as f:
                content = await f.read()
            print(f'"""\n{content!r}\n"""')


async def main():
    async with asyncssh.connect(
        server_host,
        tunnel=SocksClientConnection(),
        username=server_username,
        password=server_password,
        known_hosts=None,
    ) as conn:
        async with conn.start_sftp_client() as sftp:
            print('cwd:', await sftp.getcwd())
            await tree(sftp, '.')


if __name__ == '__main__':
    asyncio.run(main())

[ronf]

Yeah - it’s related. The example in #376 basically came out of what was discussed in #104. AsyncSSH also now supports specifying an external program to run to act as a proxy you can tunnel SSH requests over. However, that would be a lot less efficient than using aiosocks as shown in #376 for this use case.