Personal password storage :)

mypassw.rb

#!/usr/bin/env ruby
require 'digest/sha2'
require 'io/console'
require 'base64'

USAGE = <<EOF
USAGE:
  #$0 set domain [file]
    - store encoded password for domain
  #$0 domain [file]
    - feed decoded password for domain to 'xclip -i -selection clipboard'
  #$0 -c domain [file]
    - feed decoded password for domain to 'xclip -i'
  #$0 -o domain [file]
    - print decoded password for domain
  #$0 -s search [file]
    - list matched domains
  #$0 -l
    - try to decode all passwords with same master password
EOF

unless "".respond_to?(:b)
  class String; def b; force_encoding('BINARY'); end; end
end

# Main goal is simplicity of reimplementation:
# custom key deriving and custom cipher to be easy to reimplement in other languages.
# key deriving is not the safest in a world, but should be good enough unless you are James Bond or predisent of America.
# custom cipher function is certainly safe (and slow).

K = 10
M = 1024*1024
def derive(pass)
  sha = Digest::SHA512.new
  K.times do
    all = []
    (M/sha.digest_length).times do
      all << sha.update(pass).digest
    end
    sha.update(all.sort.join)
  end
  sha.update(pass)
  sha.digest
end

def encrypt(pass, domain, dpass)
  rnd = Random.new
  seed = rnd.bytes(8)
  sha = Digest::SHA512.new
  sha.update(derive(pass+seed+domain))
  dpass = "%04x%s%s" % [dpass.bytesize, dpass.b, rnd.bytes(16+rnd.rand(64))]
  dpass << sha.dup.update(dpass).digest[0,4]
  (dpass.bytesize*2).times do
    head = dpass.slice!(0,1).getbyte(0)
    dpass << (head ^ sha.dup.update(dpass).digest.getbyte(0))
  end
  Base64.strict_encode64(seed+dpass)
end

def decrypt(pass, domain, dpass)
  dpass = Base64.strict_decode64(dpass)
  seed = dpass.slice!(0,8)
  sha = Digest::SHA512.new
  sha.update(derive(pass+seed+domain))
  (dpass.bytesize*2).times do
    head = dpass.slice!(-1,1).getbyte(0)
    dpass[0,0] = (head ^ sha.dup.update(dpass).digest.getbyte(0)).chr
  end
  len = dpass[0,4].to_i(16)
  unless len <= dpass.bytesize-4 && sha.dup.update(dpass[0...-4]).digest[0,4] == dpass[-4..-1]
    return nil
  end
  dpass[4,len]
end

def decrypt_line(pass, line)
  return nil if line.nil? || line.empty?
  domain, dpass = line.split("\t", 2)
  decrypt(pass, domain, dpass)
end

def query(msg)
  if STDIN.tty?
    print msg
    pass = STDIN.noecho(&:gets).chomp.b
    print "\n"
    pass
  else
    pass = STDIN.gets.chomp.b
  end
end

def err(m)
  $stderr.puts(m)
  exit(1)
end

doset = false
dolist = false
dosearch = false
xclip = :board
case ARGV[0]
when 'set'
  doset = true
  ARGV.shift
when '-c'
  xclip = :clip
  ARGV.shift
when '-o'
  xclip = nil
  ARGV.shift
when '-s'
  dosearch = true
  ARGV.shift
when '-l'
  dolist = true
  ARGV.shift
end

domen = ARGV.shift unless dolist

if !ARGV.empty?
  file = ARGV.shift
elsif ENV["PASSW"]
  file = ENV["PASSW"]
else
  file = "~/.passw"
end
if !(dolist || !domen.nil?) || !ARGV.empty?
  puts USAGE
  exit(1)
end
file = File.expand_path(file)

if File.readable?(file)
  lines = File.open(file, "rb").readlines.map(&:chomp).select{|l| !l.empty?}
else
  lines = []
end

if dosearch
  puts lines.map{|l| l.split.first}.grep(Regexp.new(domen))
  exit(0)
end

pass = query "Master password:"

if dolist
  lines.each do |l|
    domen, crypted = l.split("\t",2)
    dpass = decrypt(pass, domen, crypted)
    if dpass.nil?
      printf("%15s !!! fail\n", domen)
    else
      printf("%15s %s\n", domen, dpass)
    end
  end
  exit(0)
end

d = domen+"\t"
if doset
  if domen =~ /^master\d+$/
    err("could not overwrite #{domen}") if lines.any?{|l| l.start_with?(d)}
    dpass = query "Repeat password:"
    err("not matched") unless pass == dpass
  else
    err("unknown master") unless lines.grep(/^master\d+\s/).any?{|l| decrypt_line(pass, l)}
    dpass = query "Domain password:"
    dpass2 = query "Repeat password:"
    err("not matched") if dpass != dpass2
  end
  lines.delete_if{|l| l.start_with?(d)}
  lines << "#{d}#{encrypt(pass, domen, dpass)}"
  File.open(file+".tmp", "wb"){|f| f.write(lines.sort.join("\n")+"\n")}
  File.rename(file+".tmp", file)
  is_git = File.exist?(File.join(File.dirname(file), ".git"))
  if is_git
    Dir.chdir(File.dirname(file)) do
      system(*%W{git commit -a -m #{Time.now}\ #{domen}})
    end
  end
else
  dpass = decrypt_line(pass, lines.find{|l| l.start_with?(d)})
  err("fail") if dpass.nil?
  case xclip
  when nil
    if STDOUT.tty?
      puts dpass
    else
      print dpass
    end
  when :clip
    IO.popen('xclip -i -l 2', 'w'){|f| f.write(dpass)}
    Process.daemon
    sleep(10)
    IO.popen('xclip -i', 'w'){|f| f.write("")}
  when :board
    IO.popen('xclip -i -l 4 -selection clipboard', 'w'){|f| f.write(dpass)}
    Process.daemon
    sleep(10)
    IO.popen('xclip -i -selection clipboard', 'w'){|f| f.write("")}
  end
end