Class: Kdbx::Header

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/kdbx/header.rb

Constant Summary collapse

FILEMAGIC = 
"\x03\xD9\xA2\x9A\x67\xFB\x4B\xB5\x01\x00\x03\x00".b

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fields = {}) ⇒ Header

Returns a new instance of Header.



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# File 'lib/kdbx/header.rb', line 25

def initialize(fields = {})
  @fields = fields
  validate
end

Class Method Details

.load(file) ⇒ Object 



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# File 'lib/kdbx/header.rb', line 7

def self.load(file)
  if file.readpartial(12) != FILEMAGIC
    fail ParseError, "bad magic number"
  end
  fields = {}
  loop do
    (id, sz) = file.readpartial(3).unpack("CS<")
    fields[id] = file.readpartial sz
    break if id == 0
  end
  new fields
rescue TypeError, EOFError
  fail ParseError, "truncated header"
end

Instance Method Details

#dump ⇒ Object 



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# File 'lib/kdbx/header.rb', line 30

def dump
  merge_defaults and validate
  StringIO.new.binmode.tap do |io|
    io.write FILEMAGIC
    @fields.each do |k, v|
      io.write [k, v.bytesize].pack("CS<") + v if k != 0
    end
    io.write [0, @fields[0].bytesize].pack("CS<") + @fields[0]
  end.string
end

#validate ⇒ Object 



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# File 'lib/kdbx/header.rb', line 41

def validate
  @fields.each do |k, v|
    fail FormatError, "header #{k.inspect}: #{v}" unless k.is_a? Integer
    fail FormatError, "header #{k}: #{v.inspect}" unless v.is_a? String
    @fields[k] = v = v.b unless v.encoding == Encoding::ASCII_8BIT
    case k
    when 2
      if v != "\x31\xC1\xF2\xE6\xBF\x71\x43\x50\xBE\x58\x05\x21\x6A\xFC\x5A\xFF".b
        fail FormatError, "header #{k}: #{v.inspect}"
      end
    when 3
      if v.bytesize != 4 || !(0..1).include?(v.unpack("L").first)
        fail FormatError, "header #{k}: #{v.inspect}"
      end
    when 4, 5
      fail FormatError, "header #{k}: #{v.inspect}" if v.bytesize != 32
    when 6
      fail FormatError, "header #{k}: #{v.inspect}" if v.bytesize != 8
    when 7
      fail FormatError, "header #{k}: #{v.inspect}" if v.bytesize != 16
    when 8
      if @fields[10] == "\x02\x00\x00\x00".b && v.bytesize != 32
        fail FormatError, "header #{k}: #{v.inspect}"
      end
    when 10
      fail FormatError, "header #{k}: #{v.inspect}" if v.bytesize != 4
      if (n = v.unpack("L<").first) != 0 && n != 2
        fail FormatError, "header #{k}: #{v.inspect}"
      end
    end
  end
end