Class Net::SSH::Authentication::Agent
In: lib/net/ssh/authentication/agent.rb
Parent: Object

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).

Methods

close   connect   connect!   identities   negotiate!   new   sign  

Included Modules

Loggable

Classes and Modules

Module Net::SSH::Authentication::Agent::Comment

Constants

SSH2_AGENT_REQUEST_VERSION = 1
SSH2_AGENT_REQUEST_IDENTITIES = 11
SSH2_AGENT_IDENTITIES_ANSWER = 12
SSH2_AGENT_SIGN_REQUEST = 13
SSH2_AGENT_SIGN_RESPONSE = 14
SSH2_AGENT_FAILURE = 30
SSH2_AGENT_VERSION_RESPONSE = 103
SSH_COM_AGENT2_FAILURE = 102
SSH_AGENT_REQUEST_RSA_IDENTITIES = 1
SSH_AGENT_RSA_IDENTITIES_ANSWER = 2
SSH_AGENT_FAILURE = 5

Attributes

socket  [R]  The underlying socket being used to communicate with the SSH agent.

Public Class methods

connect(logger=nil)

Instantiates a new agent object, connects to a running SSH agent, negotiates the agent protocol version, and returns the agent object.

[Source]

    # File lib/net/ssh/authentication/agent.rb, line 50
50:     def self.connect(logger=nil)
51:       agent = new(logger)
52:       agent.connect!
53:       agent.negotiate!
54:       agent
55:     end
new(logger=nil)

Creates a new Agent object, using the optional logger instance to report status.

[Source]

    # File lib/net/ssh/authentication/agent.rb, line 59
59:     def initialize(logger=nil)
60:       self.logger = logger
61:     end

Public Instance methods

close()

Closes this socket. This agent reference is no longer able to query the agent.

[Source]

     # File lib/net/ssh/authentication/agent.rb, line 111
111:     def close
112:       @socket.close
113:     end
connect!()

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).

[Source]

    # File lib/net/ssh/authentication/agent.rb, line 67
67:     def connect!
68:       begin
69:         debug { "connecting to ssh-agent" }
70:         @socket = agent_socket_factory.open(ENV['SSH_AUTH_SOCK'])
71:       rescue
72:         error { "could not connect to ssh-agent" }
73:         raise AgentNotAvailable, $!.message
74:       end
75:     end
identities()

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.

[Source]

     # File lib/net/ssh/authentication/agent.rb, line 93
 93:     def identities
 94:       type, body = send_and_wait(SSH2_AGENT_REQUEST_IDENTITIES)
 95:       raise AgentError, "could not get identity count" if agent_failed(type)
 96:       raise AgentError, "bad authentication reply: #{type}" if type != SSH2_AGENT_IDENTITIES_ANSWER
 97: 
 98:       identities = []
 99:       body.read_long.times do
100:         key = Buffer.new(body.read_string).read_key
101:         key.extend(Comment)
102:         key.comment = body.read_string
103:         identities.push key
104:       end
105: 
106:       return identities
107:     end
negotiate!()

Attempts to negotiate the SSH agent protocol version. Raises an error if the version could not be negotiated successfully.

[Source]

    # File lib/net/ssh/authentication/agent.rb, line 79
79:     def negotiate!
80:       # determine what type of agent we're communicating with
81:       type, body = send_and_wait(SSH2_AGENT_REQUEST_VERSION, :string, Transport::ServerVersion::PROTO_VERSION)
82: 
83:       if type == SSH2_AGENT_VERSION_RESPONSE
84:         raise NotImplementedError, "SSH2 agents are not yet supported"
85:       elsif type != SSH_AGENT_RSA_IDENTITIES_ANSWER
86:         raise AgentError, "unknown response from agent: #{type}, #{body.to_s.inspect}"
87:       end
88:     end
sign(key, data)

Using the agent and the given public key, sign the given data. The signature is returned in SSH2 format.

[Source]

     # File lib/net/ssh/authentication/agent.rb, line 117
117:     def sign(key, data)
118:       type, reply = send_and_wait(SSH2_AGENT_SIGN_REQUEST, :string, Buffer.from(:key, key), :string, data, :long, 0)
119: 
120:       if agent_failed(type)
121:         raise AgentError, "agent could not sign data with requested identity"
122:       elsif type != SSH2_AGENT_SIGN_RESPONSE
123:         raise AgentError, "bad authentication response #{type}"
124:       end
125: 
126:       return reply.read_string
127:     end

[Validate]