log/log.rb

   1 require 'openssl'
   2 require 'base64'
   3 require 'opencorn/config'
   4 require 'gpgme'
   5 require 'singleton'
   6
   7
   8 module OpenCorn
   9   class Log
  10     include Singleton
  11     @seed = nil
  12
  13     def initialize
  14       @seed=nil
  15       @seed = OpenSSL::Random::random_bytes(128)
  16       gpgdata = GPGME::Data.from_str(@seed)
  17       gpgkeys = GPGME.list_keys(OpenCorn::Config['GPG_LOG_KEYID'])
  18       raise "Too many keys for this KeyID" unless gpgkeys.size == 1
  19       gpgout = GPGME.encrypt(gpgkeys,gpgdata)
  20       #preceding 00 01 indicates a new seed for the prng encrypted with
  21       writeLog("\x00\x01"+Base64::encode64(gpgout))
  22       puts "OpenCorn::Log initialized"
  23     end
  24
  25     def prng(seed)
  26       ctx = Digest::SHA512
  27       [ctx.digest("0"+seed),ctx.digest("1"+seed)]
  28     end
  29
  30     def writeLog(msg)
  31       fp = File.open(OpenCorn::Config['LOG_FILE'],"a")
  32       fp.write(msg)
  33       fp.close
  34     end
  35
  36     def getRand()
  37         @seed,out = prng(@seed)
  38         out
  39     end
  40
  41     def cryptMsg(msg)
  42         myrand = getRand()
  43         ctx = OpenSSL::Cipher::AES256.new("OFB")
  44         ctx.iv  = myrand[0..15]  #128bit iv
  45         ctx.key = myrand[16..47] #256bit key
  46         ctext = ctx.update(msg)+ctx.final()
  47         out = OpenSSL::HMAC.digest("SHA1",myrand[48..63],ctext)+ctext
  48         #preceding 00 indicates that the base64 string is as symmetric
  49         #encrypted logentry
  50         writeLog("\x00"+Base64::encode64(out))
  51     end
  52     alias << cryptMsg
  53   end
  54 end