/usr/lib/ruby/vendor_ruby/net/ssh/authentication/methods/publickey.rb is in ruby-net-ssh 1:2.9.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 96 | 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
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