class Net::SSH::Authentication::Agent
This class implements a simple client for the ssh-agent protocol. It does not implement any specific protocol, but instead copies the behavior of the ssh-agent functions in the OpenSSH library (3.8).
This means that although it behaves like a SSH1 client, it also has some SSH2 functionality (like signing data).
Constants
- SSH2_AGENT_FAILURE
- SSH2_AGENT_IDENTITIES_ANSWER
- SSH2_AGENT_REQUEST_IDENTITIES
- SSH2_AGENT_REQUEST_VERSION
- SSH2_AGENT_SIGN_REQUEST
- SSH2_AGENT_SIGN_RESPONSE
- SSH2_AGENT_VERSION_RESPONSE
- SSH_AGENT_FAILURE
- SSH_AGENT_REQUEST_RSA_IDENTITIES
- SSH_AGENT_RSA_IDENTITIES_ANSWER1
- SSH_AGENT_RSA_IDENTITIES_ANSWER2
- SSH_COM_AGENT2_FAILURE
Attributes
The underlying socket being used to communicate with the SSH agent.
Public Class Methods
Instantiates a new agent object, connects to a running SSH agent, negotiates the agent protocol version, and returns the agent object.
# File lib/net/ssh/authentication/agent.rb, line 52 def self.connect(logger=nil, agent_socket_factory = nil) agent = new(logger) agent.connect!(agent_socket_factory) agent.negotiate! agent end
Creates a new Agent object, using the optional logger instance to report status.
# File lib/net/ssh/authentication/agent.rb, line 61 def initialize(logger=nil) self.logger = logger end
Public Instance Methods
Closes this socket. This agent reference is no longer able to query the agent.
# File lib/net/ssh/authentication/agent.rb, line 127 def close @socket.close end
Connect to the agent process using the socket factory and socket name given by the attribute writers. If the agent on the other end of the socket reports that it is an SSH2-compatible agent, this will fail (it only supports the ssh-agent distributed by OpenSSH).
# File lib/net/ssh/authentication/agent.rb, line 69 def connect!(agent_socket_factory = nil) debug { "connecting to ssh-agent" } @socket = if agent_socket_factory agent_socket_factory.call elsif ENV['SSH_AUTH_SOCK'] && defined?(unix_socket_class) unix_socket_class.open(ENV['SSH_AUTH_SOCK']) elsif Gem.win_platform? && RUBY_ENGINE != "jruby" Pageant::Socket.open else raise AgentNotAvailable, "Agent not configured" end rescue StandardError => e error { "could not connect to ssh-agent: #{e.message}" } raise AgentNotAvailable, $!.message end
Return an array of all identities (public keys) known to the agent. Each
key returned is augmented with a comment
property which is set
to the comment returned by the agent for that key.
# File lib/net/ssh/authentication/agent.rb, line 103 def identities type, body = send_and_wait(SSH2_AGENT_REQUEST_IDENTITIES) raise AgentError, "could not get identity count" if agent_failed(type) raise AgentError, "bad authentication reply: #{type}" if type != SSH2_AGENT_IDENTITIES_ANSWER identities = [] body.read_long.times do key_str = body.read_string comment_str = body.read_string begin key = Buffer.new(key_str).read_key key.extend(Comment) key.comment = comment_str identities.push key rescue NotImplementedError => e error { "ignoring unimplemented key:#{e.message} #{comment_str}" } end end return identities end
Attempts to negotiate the SSH agent protocol version. Raises an error if the version could not be negotiated successfully.
# File lib/net/ssh/authentication/agent.rb, line 88 def negotiate! # determine what type of agent we're communicating with type, body = send_and_wait(SSH2_AGENT_REQUEST_VERSION, :string, Transport::ServerVersion::PROTO_VERSION) raise AgentNotAvailable, "SSH2 agents are not yet supported" if type == SSH2_AGENT_VERSION_RESPONSE if type == SSH2_AGENT_FAILURE debug { "Unexpected response type==#{type}, this will be ignored" } elsif type != SSH_AGENT_RSA_IDENTITIES_ANSWER1 && type != SSH_AGENT_RSA_IDENTITIES_ANSWER2 raise AgentNotAvailable, "unknown response from agent: #{type}, #{body.to_s.inspect}" end end
Using the agent and the given public key, sign the given data. The signature is returned in SSH2 format.
# File lib/net/ssh/authentication/agent.rb, line 133 def sign(key, data) type, reply = send_and_wait(SSH2_AGENT_SIGN_REQUEST, :string, Buffer.from(:key, key), :string, data, :long, 0) raise AgentError, "agent could not sign data with requested identity" if agent_failed(type) raise AgentError, "bad authentication response #{type}" if type != SSH2_AGENT_SIGN_RESPONSE return reply.read_string end
Private Instance Methods
Returns true
if the parameter indicates a “failure” response
from the agent, and false
otherwise.
# File lib/net/ssh/authentication/agent.rb, line 176 def agent_failed(type) type == SSH_AGENT_FAILURE || type == SSH2_AGENT_FAILURE || type == SSH_COM_AGENT2_FAILURE end
Read the next packet from the agent. This will return a two-part tuple consisting of the packet type, and the packet's body (which is returned as a Net::SSH::Buffer).
# File lib/net/ssh/authentication/agent.rb, line 159 def read_packet buffer = Net::SSH::Buffer.new(@socket.read(4)) buffer.append(@socket.read(buffer.read_long)) type = buffer.read_byte debug { "received agent packet #{type} len #{buffer.length-4}" } return type, buffer end
Send the given packet and return the subsequent reply from the agent. (See send_packet and read_packet).
# File lib/net/ssh/authentication/agent.rb, line 169 def send_and_wait(type, *args) send_packet(type, *args) read_packet end
Send a new packet of the given type, with the associated data.
# File lib/net/ssh/authentication/agent.rb, line 149 def send_packet(type, *args) buffer = Buffer.from(*args) data = [buffer.length + 1, type.to_i, buffer.to_s].pack("NCA*") debug { "sending agent request #{type} len #{buffer.length}" } @socket.send data, 0 end
# File lib/net/ssh/authentication/agent.rb, line 144 def unix_socket_class UNIXSocket end