begin require 'securerandom' rescue LoadError end module ActiveSupport if defined?(::SecureRandom) # Use Ruby's SecureRandom library if available. SecureRandom = ::SecureRandom # :nodoc: else # = Secure random number generator interface. # # This library is an interface for secure random number generator which is # suitable for generating session key in HTTP cookies, etc. # # It supports following secure random number generators. # # * openssl # * /dev/urandom # * Win32 # # *Note*: This module is based on the SecureRandom library from Ruby 1.9, # revision 18786, August 23 2008. It's 100% interface-compatible with Ruby 1.9's # SecureRandom library. # # == Example # # # random hexadecimal string. # p SecureRandom.hex(10) # => "52750b30ffbc7de3b362" # p SecureRandom.hex(10) # => "92b15d6c8dc4beb5f559" # p SecureRandom.hex(11) # => "6aca1b5c58e4863e6b81b8" # p SecureRandom.hex(12) # => "94b2fff3e7fd9b9c391a2306" # p SecureRandom.hex(13) # => "39b290146bea6ce975c37cfc23" # ... # # # random base64 string. # p SecureRandom.base64(10) # => "EcmTPZwWRAozdA==" # p SecureRandom.base64(10) # => "9b0nsevdwNuM/w==" # p SecureRandom.base64(10) # => "KO1nIU+p9DKxGg==" # p SecureRandom.base64(11) # => "l7XEiFja+8EKEtY=" # p SecureRandom.base64(12) # => "7kJSM/MzBJI+75j8" # p SecureRandom.base64(13) # => "vKLJ0tXBHqQOuIcSIg==" # ... # # # random binary string. # p SecureRandom.random_bytes(10) # => "\016\t{\370g\310pbr\301" # p SecureRandom.random_bytes(10) # => "\323U\030TO\234\357\020\a\337" # ... # module SecureRandom # Generates a random binary string. # # The argument n specifies the length of the result string. # # If n is not specified, 16 is assumed. # It may be larger in future. # # If secure random number generator is not available, # NotImplementedError is raised. # def self.random_bytes(n=nil) n ||= 16 unless defined? OpenSSL begin require 'openssl' rescue LoadError end end if defined? OpenSSL::Random return OpenSSL::Random.random_bytes(n) end if !defined?(@has_urandom) || @has_urandom flags = File::RDONLY flags |= File::NONBLOCK if defined? File::NONBLOCK flags |= File::NOCTTY if defined? File::NOCTTY flags |= File::NOFOLLOW if defined? File::NOFOLLOW begin File.open("/dev/urandom", flags) {|f| unless f.stat.chardev? raise Errno::ENOENT end @has_urandom = true ret = f.readpartial(n) if ret.length != n raise NotImplementedError, "Unexpected partial read from random device" end return ret } rescue Errno::ENOENT @has_urandom = false end end if !defined?(@has_win32) begin require 'Win32API' crypt_acquire_context = Win32API.new("advapi32", "CryptAcquireContext", 'PPPII', 'L') @crypt_gen_random = Win32API.new("advapi32", "CryptGenRandom", 'LIP', 'L') hProvStr = " " * 4 prov_rsa_full = 1 crypt_verifycontext = 0xF0000000 if crypt_acquire_context.call(hProvStr, nil, nil, prov_rsa_full, crypt_verifycontext) == 0 raise SystemCallError, "CryptAcquireContext failed: #{lastWin32ErrorMessage}" end @hProv, = hProvStr.unpack('L') @has_win32 = true rescue LoadError @has_win32 = false end end if @has_win32 bytes = " " * n if @crypt_gen_random.call(@hProv, bytes.size, bytes) == 0 raise SystemCallError, "CryptGenRandom failed: #{lastWin32ErrorMessage}" end return bytes end raise NotImplementedError, "No random device" end # Generates a random hex string. # # The argument n specifies the length of the random length. # The length of the result string is twice of n. # # If n is not specified, 16 is assumed. # It may be larger in future. # # If secure random number generator is not available, # NotImplementedError is raised. # def self.hex(n=nil) random_bytes(n).unpack("H*")[0] end # Generates a random base64 string. # # The argument n specifies the length of the random length. # The length of the result string is about 4/3 of n. # # If n is not specified, 16 is assumed. # It may be larger in future. # # If secure random number generator is not available, # NotImplementedError is raised. # def self.base64(n=nil) [random_bytes(n)].pack("m*").delete("\n") end # Generates a random number. # # If an positive integer is given as n, # SecureRandom.random_number returns an integer: # 0 <= SecureRandom.random_number(n) < n. # # If 0 is given or an argument is not given, # SecureRandom.random_number returns an float: # 0.0 <= SecureRandom.random_number() < 1.0. # def self.random_number(n=0) if 0 < n hex = n.to_s(16) hex = '0' + hex if (hex.length & 1) == 1 bin = [hex].pack("H*") mask = bin[0] mask |= mask >> 1 mask |= mask >> 2 mask |= mask >> 4 begin rnd = SecureRandom.random_bytes(bin.length) rnd[0] = rnd[0] & mask end until rnd < bin rnd.unpack("H*")[0].hex else # assumption: Float::MANT_DIG <= 64 i64 = SecureRandom.random_bytes(8).unpack("Q")[0] Math.ldexp(i64 >> (64-Float::MANT_DIG), -Float::MANT_DIG) end end # Following code is based on David Garamond's GUID library for Ruby. def self.lastWin32ErrorMessage # :nodoc: get_last_error = Win32API.new("kernel32", "GetLastError", '', 'L') format_message = Win32API.new("kernel32", "FormatMessageA", 'LPLLPLPPPPPPPP', 'L') format_message_ignore_inserts = 0x00000200 format_message_from_system = 0x00001000 code = get_last_error.call msg = "\0" * 1024 len = format_message.call(format_message_ignore_inserts + format_message_from_system, 0, code, 0, msg, 1024, nil, nil, nil, nil, nil, nil, nil, nil) msg[0, len].tr("\r", '').chomp end end end end