From 215b54806b035509272779fefd57b432a1a0f9e5 Mon Sep 17 00:00:00 2001
From: emboss <emboss@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 20 Dec 2012 06:03:03 +0000
Subject: * ext/openssl/ossl_cipher.c: add support for Authenticated Encryption
   with Associated Data (AEAD) for OpenSSL versions that support the   GCM
 encryption mode. It's the only mode supported for now by OpenSSL   itself.
 Add Cipher#authenticated? to detect whether a chosen mode   does support
 Authenticated Encryption. * test/openssl/test_cipher.rb: add tests for
 Authenticated Encryption.   [Feature #6980] [ruby-core:47426] Thank you,
 Stephen Touset for   providing a patch!

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38488 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 test/openssl/test_cipher.rb | 141 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 137 insertions(+), 4 deletions(-)

(limited to 'test/openssl/test_cipher.rb')

diff --git a/test/openssl/test_cipher.rb b/test/openssl/test_cipher.rb
index ab131b8b1f..64c89be8b1 100644
--- a/test/openssl/test_cipher.rb
+++ b/test/openssl/test_cipher.rb
@@ -3,6 +3,25 @@ require_relative 'utils'
 if defined?(OpenSSL)
 
 class OpenSSL::TestCipher < Test::Unit::TestCase
+
+  class << self
+
+    def has_cipher?(name)
+      ciphers = OpenSSL::Cipher.ciphers
+      # redefine method so we can use the cached ciphers value from the closure
+      # and need not recompute the list each time
+      define_singleton_method :has_cipher? do |name|
+        ciphers.include?(name)
+      end
+      has_cipher?(name)
+    end 
+
+    def has_ciphers?(list)
+      list.all? { |name| has_cipher?(name) }
+    end
+
+  end
+
   def setup
     @c1 = OpenSSL::Cipher::Cipher.new("DES-EDE3-CBC")
     @c2 = OpenSSL::Cipher::DES.new(:EDE3, "CBC")
@@ -78,11 +97,8 @@ class OpenSSL::TestCipher < Test::Unit::TestCase
       cipher.decrypt
       cipher.pkcs5_keyivgen('password')
       assert_equal('hello,world', cipher.update(c) + cipher.final)
-    rescue RuntimeError => e
-      # CTR is from OpenSSL 1.0.1, and for an environment that disables CTR; No idea it exists.
-      assert_match(/unsupported cipher algorithm/, e.message)
     end
-  end
+  end if has_cipher?('aes-128-ctr')
 
   if OpenSSL::OPENSSL_VERSION_NUMBER > 0x00907000
     def test_ciphers
@@ -116,6 +132,123 @@ class OpenSSL::TestCipher < Test::Unit::TestCase
       end
     end
   end
+
+  if has_ciphers?(['aes-128-gcm', 'aes-192-gcm', 'aes-128-gcm'])
+
+    def test_authenticated
+      cipher = OpenSSL::Cipher.new('aes-128-gcm')
+      assert(cipher.authenticated?)
+      cipher = OpenSSL::Cipher.new('aes-128-cbc')
+      refute(cipher.authenticated?)
+    end
+
+    def test_aes_gcm
+      ['aes-128-gcm', 'aes-192-gcm', 'aes-128-gcm'].each do |algo|
+        pt = "You should all use Authenticated Encryption!"
+        cipher, key, iv = new_encryptor(algo)
+
+        cipher.auth_data = "aad"
+        ct  = cipher.update(pt) + cipher.final
+        tag = cipher.auth_tag
+        assert_equal(16, tag.size)
+
+        decipher = new_decryptor(algo, key, iv)
+        decipher.auth_tag = tag
+        decipher.auth_data = "aad"
+
+        assert_equal(pt, decipher.update(ct) + decipher.final)
+      end
+    end
+
+    def test_aes_gcm_short_tag
+      ['aes-128-gcm', 'aes-192-gcm', 'aes-128-gcm'].each do |algo|
+        pt = "You should all use Authenticated Encryption!"
+        cipher, key, iv = new_encryptor(algo)
+
+        cipher.auth_data = "aad"
+        ct  = cipher.update(pt) + cipher.final
+        tag = cipher.auth_tag(8)
+        assert_equal(8, tag.size)
+
+        decipher = new_decryptor(algo, key, iv)
+        decipher.auth_tag = tag
+        decipher.auth_data = "aad"
+
+        assert_equal(pt, decipher.update(ct) + decipher.final)
+      end
+    end
+
+    def test_aes_gcm_wrong_tag
+      pt = "You should all use Authenticated Encryption!"
+      cipher, key, iv = new_encryptor('aes-128-gcm')
+
+      cipher.auth_data = "aad"
+      ct  = cipher.update(pt) + cipher.final
+      tag = cipher.auth_tag
+
+      decipher = new_decryptor('aes-128-gcm', key, iv)
+      decipher.auth_tag = tag[0..-2] << tag[-1].succ
+      decipher.auth_data = "aad"
+
+      assert_raise OpenSSL::Cipher::CipherError do
+        decipher.update(ct) + decipher.final
+      end
+    end
+
+    def test_aes_gcm_wrong_auth_data
+      pt = "You should all use Authenticated Encryption!"
+      cipher, key, iv = new_encryptor('aes-128-gcm')
+
+      cipher.auth_data = "aad"
+      ct  = cipher.update(pt) + cipher.final
+      tag = cipher.auth_tag
+
+      decipher = new_decryptor('aes-128-gcm', key, iv)
+      decipher.auth_tag = tag
+      decipher.auth_data = "daa"
+
+      assert_raise OpenSSL::Cipher::CipherError do
+        decipher.update(ct) + decipher.final
+      end
+    end
+
+    def test_aes_gcm_wrong_ciphertext
+      pt = "You should all use Authenticated Encryption!"
+      cipher, key, iv = new_encryptor('aes-128-gcm')
+
+      cipher.auth_data = "aad"
+      ct  = cipher.update(pt) + cipher.final
+      tag = cipher.auth_tag
+
+      decipher = new_decryptor('aes-128-gcm', key, iv)
+      decipher.auth_tag = tag
+      decipher.auth_data = "aad"
+
+      assert_raise OpenSSL::Cipher::CipherError do
+        decipher.update(ct[0..-2] << ct[-1].succ) + decipher.final
+      end
+    end
+
+  end
+
+  private
+
+  def new_encryptor(algo)
+    cipher = OpenSSL::Cipher.new(algo)
+    cipher.encrypt
+    key = cipher.random_key
+    iv = cipher.random_iv
+    [cipher, key, iv]
+  end
+
+  def new_decryptor(algo, key, iv)
+    OpenSSL::Cipher.new(algo).tap do |cipher|
+      cipher.decrypt
+      cipher.key = key
+      cipher.iv = iv
+    end
+  end
+
 end
 
 end
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