1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
require 'net/ssh/buffer'
require 'net/ssh/errors'
require 'net/ssh/authentication/methods/abstract'
module Net
module SSH
module Authentication
module Methods
# Implements the "publickey" SSH authentication method.
class Publickey < Abstract
# Attempts to perform public-key authentication for the given
# username, trying each identity known to the key manager. If any of
# them succeed, returns +true+, otherwise returns +false+. This
# requires the presence of a key manager.
def authenticate(next_service, username, password=nil)
return false unless key_manager
key_manager.each_identity do |identity|
return true if authenticate_with(identity, next_service, username)
end
return false
end
private
# Builds a packet that contains the request formatted for sending
# a public-key request to the server.
def build_request(pub_key, username, next_service, has_sig)
blob = Net::SSH::Buffer.new
blob.write_key pub_key
userauth_request(username, next_service, "publickey", has_sig,
pub_key.ssh_type, blob.to_s)
end
# Builds and sends a request formatted for a public-key
# authentication request.
def send_request(pub_key, username, next_service, signature=nil)
msg = build_request(pub_key, username, next_service, !signature.nil?)
msg.write_string(signature) if signature
send_message(msg)
end
# Attempts to perform public-key authentication for the given
# username, with the given identity (public key). Returns +true+ if
# successful, or +false+ otherwise.
def authenticate_with(identity, next_service, username)
debug { "trying publickey (#{identity.fingerprint})" }
send_request(identity, username, next_service)
message = session.next_message
case message.type
when USERAUTH_PK_OK
buffer = build_request(identity, username, next_service, true)
sig_data = Net::SSH::Buffer.new
sig_data.write_string(session_id)
sig_data.append(buffer.to_s)
sig_blob = key_manager.sign(identity, sig_data)
send_request(identity, username, next_service, sig_blob.to_s)
message = session.next_message
case message.type
when USERAUTH_SUCCESS
debug { "publickey succeeded (#{identity.fingerprint})" }
return true
when USERAUTH_FAILURE
debug { "publickey failed (#{identity.fingerprint})" }
raise Net::SSH::Authentication::DisallowedMethod unless
message[:authentications].split(/,/).include? 'publickey'
return false
else
raise Net::SSH::Exception,
"unexpected server response to USERAUTH_REQUEST: #{message.type} (#{message.inspect})"
end
when USERAUTH_FAILURE
return false
else
raise Net::SSH::Exception, "unexpected reply to USERAUTH_REQUEST: #{message.type} (#{message.inspect})"
end
end
end
end
end
end
end
|
