Class: Keepassx::Header

Inherits:
Object
  • Object
show all
Defined in:
lib/keepassx/header.rb

Constant Summary collapse

ENCRYPTION_FLAGS = 
[
    [1, 'SHA2'],
    [2, 'Rijndael'],
    [2, 'AES'],
    [4, 'ArcFour'],
    [8, 'TwoFish']
]
FIELDS = 
[
    :signature1,
    :signature2,
    :flags,
    :version,
    :master_seed,
    :encryption_iv,
    :group_number,
    :entry_number,
    :contents_hash,
    :master_seed2,
    :rounds
]
SIGNATURES = 
[0x9AA2D903, 0xB54BFB65]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(header_bytes = nil) ⇒ Header

Returns a new instance of Header.



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# File 'lib/keepassx/header.rb', line 67

def initialize(header_bytes = nil)
  if header_bytes.nil?
    self.signature1, self.signature2 = SIGNATURES
    self.flags = 3 # SHA2 hashing, AES encryption
    self.version = 0x30002

    self.master_seed = SecureRandom.random_bytes(16)
    self.encryption_iv = SecureRandom.random_bytes(16)
    self.master_seed2 = SecureRandom.random_bytes(32)

    self.group_number = 0
    self.entry_number = 0
    self.rounds = 50000
  else
    header_bytes = StringIO.new header_bytes
    self.signature1 = header_bytes.read(4).unpack('L*').first
    self.signature2 = header_bytes.read(4).unpack('L*').first
    self.flags = header_bytes.read(4).unpack('L*').first
    self.version = header_bytes.read(4).unpack('L*').first
    self.master_seed = header_bytes.read(16)
    self.encryption_iv = header_bytes.read(16)
    self.group_number = header_bytes.read(4).unpack('L*').first
    self.entry_number = header_bytes.read(4).unpack('L*').first
    self.contents_hash = header_bytes.read(32)
    self.master_seed2 = header_bytes.read(32)
    self.rounds = header_bytes.read(4).unpack('L*').first
  end
end

Instance Attribute Details

#contents_hash ⇒ Object

Returns the value of attribute contents_hash.



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# File 'lib/keepassx/header.rb', line 62

def contents_hash
  @contents_hash
end

#encryption_iv ⇒ Object

Returns the value of attribute encryption_iv.



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# File 'lib/keepassx/header.rb', line 62

def encryption_iv
  @encryption_iv
end

#entry_number ⇒ Object

Returns the value of attribute entry_number.



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# File 'lib/keepassx/header.rb', line 62

def entry_number
  @entry_number
end

#flags ⇒ Object

Returns the value of attribute flags.



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# File 'lib/keepassx/header.rb', line 63

def flags
  @flags
end

#group_number ⇒ Object

Returns the value of attribute group_number.



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# File 'lib/keepassx/header.rb', line 62

def group_number
  @group_number
end

#master_seed ⇒ Object

Returns the value of attribute master_seed.



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# File 'lib/keepassx/header.rb', line 63

def master_seed
  @master_seed
end

#master_seed2 ⇒ Object

Returns the value of attribute master_seed2.



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# File 'lib/keepassx/header.rb', line 63

def master_seed2
  @master_seed2
end

#rounds ⇒ Object

Returns the value of attribute rounds.



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# File 'lib/keepassx/header.rb', line 63

def rounds
  @rounds
end

#signature1 ⇒ Object

Returns the value of attribute signature1.



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# File 'lib/keepassx/header.rb', line 63

def signature1
  @signature1
end

#signature2 ⇒ Object

Returns the value of attribute signature2.



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# File 'lib/keepassx/header.rb', line 63

def signature2
  @signature2
end

#version ⇒ Object

Returns the value of attribute version.



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# File 'lib/keepassx/header.rb', line 63

def version
  @version
end

Instance Method Details

#encode ⇒ String

Return encoded header

Returns:

  • (String) —

    Encoded header representation.



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# File 'lib/keepassx/header.rb', line 109

def encode
  [signature1].pack('L*') <<
      [signature2].pack('L*') <<
      [flags].pack('L*') <<
      [version].pack('L*') <<
      master_seed <<
      encryption_iv <<
      [group_number].pack('L*') <<
      [entry_number].pack('L*') <<
      contents_hash <<
      master_seed2 <<
      [rounds].pack('L*')

end

#encryption_type ⇒ Object 



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# File 'lib/keepassx/header.rb', line 130

def encryption_type
  ENCRYPTION_FLAGS.each do |(flag_mask, encryption_type)|
    return encryption_type if flags & flag_mask
  end
  'Unknown'
end

#final_key(master_key, keyfile_data = nil) ⇒ Object 



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# File 'lib/keepassx/header.rb', line 138

def final_key(master_key, keyfile_data=nil)
  key = Digest::SHA2.new.update(master_key).digest

  if keyfile_data
    if keyfile_data.size == 64 # Hex encoded key
      keyfile_hash = [keyfile_data].pack("H*")
    elsif keyfile_data.size == 32 # Raw key
      keyfile_hash = keyfile_data
    else
      keyfile_hash = Digest::SHA2.new.update(keyfile_data).digest
    end

    if master_key == ""
      key = keyfile_hash
    else
      key = Digest::SHA2.new.update(key + keyfile_hash).digest
    end
  end

  aes = OpenSSL::Cipher::Cipher.new('AES-256-ECB')
  aes.encrypt
  aes.key = master_seed2
  aes.padding = 0

  rounds.times do
    key = aes.update(key) + aes.final
  end

  key = Digest::SHA2.new.update(key).digest
  Digest::SHA2.new.update(master_seed + key).digest

end

#length ⇒ Object 



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# File 'lib/keepassx/header.rb', line 97

def length
  length = 0
  FIELDS.each do |field|
    length += field.length
  end
  length
end

#valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/keepassx/header.rb', line 125

def valid?
  signature1 == SIGNATURES[0] && signature2 == SIGNATURES[1]
end