DSA reenvío de claves con Paramiko?
Estoy usando Paramiko para ejecutar scripts de bash en un servidor remoto. En algunos de estos scripts, hay conexiones ssh a otros servidores. Si solo uso bash, no Python, mi clave DSA es reenviada y utilizada por el script bash en el primer servidor remoto para conectarse al segundo servidor remoto. Cuando uso Paramiko no es el caso.
Ejemplo de Bash:
Jean@mydesktop:~ & ssh root@firstserver
root@firstserver:~ # ssh root@secondserver hostname
secondserver.mydomain.org
Usando Paramiko:
#!/usr/bin/python3
# -*- coding: utf-8 -*-
import paramiko
class SSHSession:
def __init__(self, server_address, user='root', port=22):
self.connected = False
self.server_address = server_address
self.user = user
self.port = port
def connect(self, clear_channel=True):
try:
if self.server_address == None:
raise ValueError('No hostname')
except:
raise ValueError('No hostname')
else:
try:
self.ssh_client = paramiko.SSHClient()
self.ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
self.ssh_client.connect(self.server_address, username=self.user)
#self.transport = self.ssh_client.get_transport()
#self.channel = self.transport.open_forward_agent_channel()
self.channel = self.ssh_client.invoke_shell()
except:
self.connected = False
return False
else:
self.connected = True
return True
def exec_command(self, command, newline='\r'):
if not self.connected:
raise Exception('Not connected')
else:
timeout = 31536000 # 365 days in seconds
self.channel.settimeout(timeout)
line_buffer = ''
channel_buffer = ''
end_string = 'CLIENT_EXPECT_CMD_OK'
print('[SEND ] >>', command)
self.channel.send(command + ' ; echo ' + end_string + newline)
while True:
channel_buffer = self.channel.recv(1).decode('UTF-8')
if len(channel_buffer) == 0:
raise Exception('connection lost with server: ' + self.server_address)
break
channel_buffer = channel_buffer.replace('\r', '')
if channel_buffer != '\n':
line_buffer += channel_buffer
else:
if line_buffer == end_string:
break
print('[RECEIVE] <<', line_buffer)
line_buffer = ''
def disconnect(self):
self.ssh_client.close()
def __enter__(self):
self.connect()
return self
def __exit__(self, _type, value, traceback):
self.disconnect()
if __name__ == "__main__":
server_address = 'firstserver'
ssh_user = 'root'
with SSHSession(server_address) as ssh_session:
ssh_session.exec_command('hostname')
ssh_session.exec_command('ssh root@secondserver hostname')
Salida es:
[SEND ] >> hostname
[RECEIVE] << [root@firstserver ~]# hostname ; echo CLIENT_EXPECT_CMD_OK
[RECEIVE] << firstserver.mydomain.fr
[SEND ] >> ssh root@secondserver hostname
[RECEIVE] << [root@firstserver ~]# ssh root@secondserver hostname ; echo CLIENT_EXPECT_CMD_OK
[RECEIVE] << Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
Lo intenté:
self.transport = self.ssh_client.get_transport()
self.channel = self.transport.open_forward_agent_channel()
en vez de :
self.channel = self.ssh_client.invoke_shell()
pero luego me sale un error:
paramiko.ssh_exception.ChannelException: Administratively prohibited
¿Alguien sabe si esto es posible? Encontré discusiones que sugieren que es así, pero aún no encuentro cómo hacer esto.