Module: CyberplatPKI::PacketIORoutines

Defined in:
lib/cyberplat_pki/packet_io_routines.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#checksum ⇒ Object

Returns the value of attribute checksum.



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 6

def checksum
  @checksum
end

#cipher ⇒ Object

Returns the value of attribute cipher.



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 6

def cipher
  @cipher
end

Instance Method Details

#read_mpi ⇒ Object 



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 65

def read_mpi
  header = read(2)

  mpi_bits, = header.unpack("n")
  data = read((mpi_bits + 7) / 8)

  if !cipher.nil?
    cipher.resync
    data = cipher.decrypt data
  end

  add_checksum header
  add_checksum data

  OpenSSL::BN.new data, 2
end

#read_packet(password = nil) ⇒ Object 



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 8

def read_packet(password = nil)
  header = readbyte
  raise "CyberplatPKI: CRYPT_ERR_INVALID_PACKET_FORMAT (invalid packet header)" if (header & 0xC0) != 0x80

  case header & 3
  when 0
    data_length = readbyte

  when 1
    data_length, = read(2).unpack 'n'

  when 2
    data_length, = read(4).unpack 'N'

  else
    raise "CyberplatPKI: CRYPT_ERR_INVALID_PACKET_FORMAT (invalid packet length type: #{header % 3}"
  end

  packet_type = (header >> 2) & 0x0F

  data = read data_length
  packet_class = PACKET_TYPES[packet_type]

  raise "CyberplatPKI: CRYPT_ERR_INVALID_PACKET_FORMAT (unsupported packet type: #{packet_type})" if packet_class.nil?

  StringIO.open(data, "rb") do |io|
    io.extend PacketIORoutines
    packet_class.load io, context_for_password(password)
  end
end

#write_mpi(bn) ⇒ Object 



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 82

def write_mpi(bn)
  header = [ bn.num_bits ].pack("n")
  data = bn.to_s 2

  add_checksum header
  add_checksum data

  write header

  if !cipher.nil?
    cipher.resync
    data = cipher.encrypt data
  end

  write data
end

#write_packet(packet, password = nil) ⇒ Object 



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# File 'lib/cyberplat_pki/packet_io_routines.rb', line 39

def write_packet(packet, password = nil)
  io = StringIO.open ''.encode('BINARY'), 'wb'
  io.extend PacketIORoutines
  packet.save io, context_for_password(password)

  data = io.string

  packet_type = (PACKET_TYPES.key(packet.class) << 2) | 0x80

  if data.length <= 0xFF && !packet.kind_of?(SignaturePacket) && !packet.kind_of?(KeyPacket)
    putc packet_type
    putc data.length
  elsif data.length <= 0xFFFF
    putc packet_type | 1

    write [ data.length ].pack("n")

  else
    putc packet_type | 2

    write [ data.length ].pack("N")
  end

  write data
end