bh_sshserver.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Mon Jun 22 22:07:38 2020

@author: edoardottt
"""

import socket
import paramiko
import threading
import sys

# using the key from the Paramiko demo files
host_key = paramiko.RSAKey(filename="test_rsa.key")


class Server(paramiko.ServerInterface):
    def __init__(self):
        self.event = threading.Event()

    def check_channel_request(self, kind, chanid):
        if kind == "session":
            return paramiko.OPEN_SUCCEEDED
        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED

    def check_auth_password(self, username, password):
        if username == "justin" and password == "lovesthepython":
            return paramiko.AUTH_SUCCESSFUL
        return paramiko.AUTH_FAILED


server = sys.argv[1]

ssh_port = int(sys.argv[2])

try:
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind((server, ssh_port))
    sock.listen(100)
    print("[+] Listening for connection...")
    client, addr = sock.accept()

except Exception as e:
    print("[-] Listen failed: " + str(e))
    sys.exit(1)
print("[+] Got a connection!")

try:
    bhSession = paramiko.Transport(client)
    bhSession.add_server_key(host_key)

    server = Server()
    try:
        bhSession.start_server(server=server)
    except paramiko.SSHException as x:
        print("[-] Negotiation failed.")
    chan = bhSession.accept(20)
    print("[+] Authenticated!")
    print(chan.recv(1024))
    chan.send("Welcome to bh_ssh!")

    while True:
        try:
            command = input("Enter command: ").strip("\n")
            if command != "exit":
                chan.send(command)
                print(chan.recv(1024) + "\n")
            else:
                chan.send("exit")
                print("exiting")
                bhSession.close()
                raise Exception("exit")
        except Exception as e:
            print("[-] Caught exception: " + str(e))
            try:
                bhSession.close()
            except:
                pass
            sys.exit(1)
except:
    pass