Deprecate Rails::SecretKeyGenerator in favor of ActiveSupport::SecureRandom.

SecureRandom has a few minor security enhancements and can be used as a drop-in replacement

Signed-off-by: Michael Koziarski <michael@koziarski.com>
[#913 state:committed]

4 files changed, 8 insertions, 161 deletions

diff --git a/railties/lib/rails_generator/generators/applications/app/app_generator.rb b/railties/lib/rails_generator/generators/applications/app/app_generator.rb
index 80e8eabfd3..9849948339 100644
--- a/railties/lib/rails_generator/generators/applications/app/app_generator.rb
+++ b/railties/lib/rails_generator/generators/applications/app/app_generator.rb
@@ -1,6 +1,5 @@
 require 'rbconfig'
 require 'digest/md5' 
-require 'rails_generator/secret_key_generator'
 
 class AppGenerator < Rails::Generator::Base
   DEFAULT_SHEBANG = File.join(Config::CONFIG['bindir'],
@@ -36,7 +35,7 @@ class AppGenerator < Rails::Generator::Base
     md5 << @app_name
 
     # Do our best to generate a secure secret key for CookieStore
-    secret = Rails::SecretKeyGenerator.new(@app_name).generate_secret
+    secret = ActiveSupport::SecureRandom.hex(64)
 
     record do |m|
       # Root directory and all subdirectories.
diff --git a/railties/lib/rails_generator/secret_key_generator.rb b/railties/lib/rails_generator/secret_key_generator.rb
index 5ae492312e..e92ca125a2 100644
--- a/railties/lib/rails_generator/secret_key_generator.rb
+++ b/railties/lib/rails_generator/secret_key_generator.rb
@@ -5,160 +5,17 @@ module Rails
   #
   #   generator = Rails::SecretKeyGenerator("some unique identifier, such as the application name")
   #   generator.generate_secret     # => "f3f1be90053fa851... (some long string)"
+  #
+  # This class is *deprecated* in Rails 2.2 in favor of ActiveSupport::SecureRandom.
+  # It is currently a wrapper around ActiveSupport::SecureRandom.
   class SecretKeyGenerator
-    GENERATORS = [ :secure_random, :win32_api, :urandom, :openssl, :prng ].freeze
-
     def initialize(identifier)
-      @identifier = identifier
     end
 
     # Generate a random secret key with the best possible method available on
     # the current platform.
     def generate_secret
-      generator = GENERATORS.find do |g|
-        self.class.send("supports_#{g}?")
-      end
-      send("generate_secret_with_#{generator}")
-    end
-
-    # Generate a random secret key by using the Win32 API. Raises LoadError
-    # if the current platform cannot make use of the Win32 API. Raises
-    # SystemCallError if some other error occurred.
-    def generate_secret_with_win32_api
-      # Following code is based on David Garamond's GUID library for Ruby.
-      require 'Win32API'
-
-      crypt_acquire_context = Win32API.new("advapi32", "CryptAcquireContext",
-                                           'PPPII', 'L')
-      crypt_gen_random = Win32API.new("advapi32", "CryptGenRandom",
-                                      'LIP', 'L')
-      crypt_release_context = Win32API.new("advapi32", "CryptReleaseContext",
-                                         'LI', 'L')
-      prov_rsa_full       = 1
-      crypt_verifycontext = 0xF0000000
-
-      hProvStr = " " * 4
-      if crypt_acquire_context.call(hProvStr, nil, nil, prov_rsa_full,
-                                    crypt_verifycontext) == 0
-        raise SystemCallError, "CryptAcquireContext failed: #{lastWin32ErrorMessage}"
-      end
-      hProv, = hProvStr.unpack('L')
-      bytes = " " * 64
-      if crypt_gen_random.call(hProv, bytes.size, bytes) == 0
-        raise SystemCallError, "CryptGenRandom failed: #{lastWin32ErrorMessage}"
-      end
-      if crypt_release_context.call(hProv, 0) == 0
-        raise SystemCallError, "CryptReleaseContext failed: #{lastWin32ErrorMessage}"
-      end
-      bytes.unpack("H*")[0]
-    end
-
-    # Generate a random secret key with Ruby 1.9's SecureRandom module.
-    # Raises LoadError if the current Ruby version does not support
-    # SecureRandom.
-    def generate_secret_with_secure_random
-      require 'securerandom'
-      return SecureRandom.hex(64)
-    end
-
-    # Generate a random secret key with OpenSSL. If OpenSSL is not
-    # already loaded, then this method will attempt to load it.
-    # LoadError will be raised if that fails.
-    def generate_secret_with_openssl
-      require 'openssl'
-      if !File.exist?("/dev/urandom")
-        # OpenSSL transparently seeds the random number generator with
-        # data from /dev/urandom. On platforms where that is not
-        # available, such as Windows, we have to provide OpenSSL with
-        # our own seed. Unfortunately there's no way to provide a
-        # secure seed without OS support, so we'll have to do with
-        # rand() and Time.now.usec().
-        OpenSSL::Random.seed(rand(0).to_s + Time.now.usec.to_s)
-      end
-      data = OpenSSL::BN.rand(2048, -1, false).to_s
-
-      if OpenSSL::OPENSSL_VERSION_NUMBER > 0x00908000
-        OpenSSL::Digest::SHA512.new(data).hexdigest
-      else
-        generate_secret_with_prng
-      end
+      ActiveSupport::SecureRandom.hex(64)
     end
-
-    # Generate a random secret key with /dev/urandom.
-    # Raises SystemCallError on failure.
-    def generate_secret_with_urandom
-      return File.read("/dev/urandom", 64).unpack("H*")[0]
-    end
-
-    # Generate a random secret key with Ruby's pseudo random number generator,
-    # as well as some environment information.
-    #
-    # This is the least cryptographically secure way to generate a secret key,
-    # and should be avoided whenever possible.
-    def generate_secret_with_prng
-      require 'digest/sha2'
-      sha = Digest::SHA2.new(512)
-      now = Time.now
-      sha << now.to_s
-      sha << String(now.usec)
-      sha << String(rand(0))
-      sha << String($$)
-      sha << @identifier
-      return sha.hexdigest
-    end
-
-    private
-      def lastWin32ErrorMessage
-        # Following code is based on David Garamond's GUID library for Ruby.
-        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
-
-      def self.supports_secure_random?
-        begin
-          require 'securerandom'
-          true
-        rescue LoadError
-          false
-        end
-      end
-
-      def self.supports_win32_api?
-        return false unless RUBY_PLATFORM =~ /(:?mswin|mingw)/
-        begin
-          require 'Win32API'
-          true
-        rescue LoadError
-          false
-        end
-      end
-
-      def self.supports_urandom?
-        File.exist?('/dev/urandom')
-      end
-
-      def self.supports_openssl?
-        begin
-          require 'openssl'
-          true
-        rescue LoadError
-          false
-        end
-      end
-
-      def self.supports_prng?
-        true
-      end
   end
 end
diff --git a/railties/lib/tasks/misc.rake b/railties/lib/tasks/misc.rake
index 33bbba1101..5c99725203 100644
--- a/railties/lib/tasks/misc.rake
+++ b/railties/lib/tasks/misc.rake
@@ -3,10 +3,9 @@ task :environment do
   require(File.join(RAILS_ROOT, 'config', 'environment'))
 end
 
-require 'rails_generator/secret_key_generator'
-desc 'Generate a crytographically secure secret key. This is typically used to generate a secret for cookie sessions. Pass a unique identifier to the generator using ID="some unique identifier" for greater security.'
+desc 'Generate a crytographically secure secret key. This is typically used to generate a secret for cookie sessions.'
 task :secret do
-  puts Rails::SecretKeyGenerator.new(ENV['ID']).generate_secret
+  puts ActiveSupport::SecureRandom.hex(64)
 end
 
 require 'active_support'
@@ -54,4 +53,4 @@ namespace :time do
       puts "\n"
     end
   end
-end
\ No newline at end of file
+end
diff --git a/railties/test/secret_key_generation_test.rb b/railties/test/secret_key_generation_test.rb
index ea1b0dae31..2a04cff856 100644
--- a/railties/test/secret_key_generation_test.rb
+++ b/railties/test/secret_key_generation_test.rb
@@ -33,12 +33,4 @@ class SecretKeyGenerationTest < Test::Unit::TestCase
   def test_secret_key_generation
     assert @generator.generate_secret.length >= SECRET_KEY_MIN_LENGTH
   end
-
-  Rails::SecretKeyGenerator::GENERATORS.each do |generator|
-    if Rails::SecretKeyGenerator.send("supports_#{generator}?")
-      define_method("test_secret_key_generation_with_#{generator}") do
-        assert @generator.send("generate_secret_with_#{generator}").length >= SECRET_KEY_MIN_LENGTH
-      end
-    end
-  end
 end