class DBus::DBusCookieSHA1

Authentication class using SHA1 crypto algorithm

Class for ‘CookieSHA1’ type authentication. Implements the AUTH DBUS_COOKIE_SHA1 mechanism.

Public Instance Methods

authenticate() click to toggle source

the autenticate method (called in stage one of authentification)

   # File lib/dbus/auth.rb
52 def authenticate
53   require "etc"
54   # number of retries we have for auth
55   @retries = 1
56   hex_encode(Etc.getlogin).to_s # server expects it to be binary
57 end
data(hexdata) click to toggle source

handles the interesting crypto stuff, check the rbus-project for more info: rbus.rubyforge.org/

   # File lib/dbus/auth.rb
65 def data(hexdata)
66   require "digest/sha1"
67   data = hex_decode(hexdata)
68   # name of cookie file, id of cookie in file, servers random challenge
69   context, id, s_challenge = data.split(" ")
70   # Random client challenge
71   c_challenge = 1.upto(s_challenge.bytesize / 2).map { rand(255).to_s }.join
72   # Search cookie file for id
73   path = File.join(ENV["HOME"], ".dbus-keyrings", context)
74   DBus.logger.debug "path: #{path.inspect}"
75   File.foreach(path) do |line|
76     if line.index(id).zero?
77       # Right line of file, read cookie
78       cookie = line.split(" ")[2].chomp
79       DBus.logger.debug "cookie: #{cookie.inspect}"
80       # Concatenate and encrypt
81       to_encrypt = [s_challenge, c_challenge, cookie].join(":")
82       sha = Digest::SHA1.hexdigest(to_encrypt)
83       # the almighty tcp server wants everything hex encoded
84       hex_response = hex_encode("#{c_challenge} #{sha}")
85       # Return response
86       response = [:AuthOk, hex_response]
87       return response
88     end
89   end
90   # a little rescue magic
91   unless @retries <= 0
92     puts "ERROR: Could not auth, will now exit."
93     puts "ERROR: Unable to locate cookie, retry in 1 second."
94     @retries -= 1
95     sleep 1
96     data(hexdata)
97   end
98 end
hex_decode(encoded) click to toggle source

decode hex to plain

    # File lib/dbus/auth.rb
107 def hex_decode(encoded)
108   encoded.scan(/[[:xdigit:]]{2}/).map { |h| h.hex.chr }.join
109 end
hex_encode(plain) click to toggle source

encode plain to hex

    # File lib/dbus/auth.rb
101 def hex_encode(plain)
102   return nil if plain.nil?
103   plain.to_s.unpack("H*")[0]
104 end
name() click to toggle source

returns the modules name

   # File lib/dbus/auth.rb
60 def name
61   "DBUS_COOKIE_SHA1"
62 end