Add support for loading private keys into SSH agent

[omribahumi]

I would like to load private keys from a key store into my ssh-agent.
This looks well documented on https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.agent
This looks like it belongs in paramiko.agent.AgentSSH, perhaps a add_key or a load_key method that accepts a paramiko.pkey.PKey ?

[bitprophet]

Sounds like a good feature-add offhand, thanks for the report :)

[mmetelskiy]

I failed to implement the poc but here is what I have
Documentation moved to new location - pay attention to version
Other useful docs could be found here
My code:

import paramiko
from paramiko.message import Message
from paramiko.py3compat import byte_chr

private_key_file_path = '<path_to_private_rsa_key>'

SSH_AGENT_FAILURE = 5
SSH_AGENT_SUCCESS = 6
cSSH2_AGENTC_ADD_IDENTITY = byte_chr(17)

key = paramiko.RSAKey.from_private_key_file(private_key_file_path)

key_type = key.get_name()  # not sure that this will work with other key types

content = Message()
content.add_byte(cSSH2_AGENTC_ADD_IDENTITY)
content.add_string(key_type)
content.add_mpint(key.public_numbers.n)
content.add_mpint(key.public_numbers.e)
content.add_mpint(key.key.private_numbers().d)
content.add_mpint(key.key.private_numbers().iqmp)
content.add_mpint(key.key.private_numbers().p)
content.add_mpint(key.key.private_numbers().q)

msg = Message()
msg.add_byte(cSSH2_AGENTC_ADD_IDENTITY)
msg.add_string(key_type)
msg.add_bytes(content.asbytes())

agent = paramiko.Agent()
ptype, result = agent._send_message(msg)

print(ptype)

ssh-agent is running with -d flag and here are the logs (only part that appears after running the above code):

debug2: fd 4 setting O_NONBLOCK
debug1: type 11
debug1: type 17
process_add_identity: decode private key: string is too large
debug1: XXX shrink: 3 < 4

I stopped at this point and moved to using ssh-add in bash
Python solution with subprocesses: link

[mmetelskiy]

Upd: made it work in 5 minutes
Removing the duplicated cSSH2_AGENTC_ADD_IDENTITY and key_type params fixed the issue