AEAD encrypted cookies and sessions

This commit changes encrypted cookies from AES in CBC HMAC mode to
Authenticated Encryption using AES-GCM. It also provides a cookie jar
to transparently upgrade encrypted cookies to this new scheme. Some
other notable changes include:

- There is a new application configuration value:
  +use_authenticated_cookie_encryption+. When enabled, AEAD encrypted
  cookies will be used.

- +cookies.signed+ does not raise a +TypeError+ now if the name of an
  encrypted cookie is used. Encrypted cookies using the same key as
  signed cookies would be verified and serialization would then fail
  due the message still be encrypted.

1 files changed, 120 insertions, 86 deletions

diff --git a/actionpack/test/dispatch/cookies_test.rb b/actionpack/test/dispatch/cookies_test.rb
index 664faa31bb..e5646de82e 100644
--- a/actionpack/test/dispatch/cookies_test.rb
+++ b/actionpack/test/dispatch/cookies_test.rb
@@ -288,8 +288,7 @@ class CookiesTest < ActionController::TestCase
     @request.env["action_dispatch.key_generator"] = ActiveSupport::KeyGenerator.new(SALT, iterations: 2)
 
     @request.env["action_dispatch.signed_cookie_salt"] =
-      @request.env["action_dispatch.encrypted_cookie_salt"] =
-      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+      @request.env["action_dispatch.authenticated_encrypted_cookie_salt"] = SALT
 
     @request.host = "www.nextangle.com"
   end
@@ -531,9 +530,7 @@ class CookiesTest < ActionController::TestCase
     get :set_encrypted_cookie
     cookies = @controller.send :cookies
     assert_not_equal "bar", cookies[:foo]
-    assert_raise TypeError do
-      cookies.signed[:foo]
-    end
+    assert_nil cookies.signed[:foo]
     assert_equal "bar", cookies.encrypted[:foo]
   end
 
@@ -542,9 +539,7 @@ class CookiesTest < ActionController::TestCase
     get :set_encrypted_cookie
     cookies = @controller.send :cookies
     assert_not_equal "bar", cookies[:foo]
-    assert_raises TypeError do
-      cookies.signed[:foo]
-    end
+    assert_nil cookies.signed[:foo]
     assert_equal "bar", cookies.encrypted[:foo]
   end
 
@@ -553,9 +548,7 @@ class CookiesTest < ActionController::TestCase
     get :set_encrypted_cookie
     cookies = @controller.send :cookies
     assert_not_equal "bar", cookies[:foo]
-    assert_raises ::JSON::ParserError do
-      cookies.signed[:foo]
-    end
+    assert_nil cookies.signed[:foo]
     assert_equal "bar", cookies.encrypted[:foo]
   end
 
@@ -564,9 +557,7 @@ class CookiesTest < ActionController::TestCase
     get :set_wrapped_encrypted_cookie
     cookies = @controller.send :cookies
     assert_not_equal "wrapped: bar", cookies[:foo]
-    assert_raises ::JSON::ParserError do
-      cookies.signed[:foo]
-    end
+    assert_nil cookies.signed[:foo]
     assert_equal "wrapped: bar", cookies.encrypted[:foo]
   end
 
@@ -577,38 +568,16 @@ class CookiesTest < ActionController::TestCase
     assert_equal "bar was dumped and loaded", cookies.encrypted[:foo]
   end
 
-  def test_encrypted_cookie_using_custom_digest
-    @request.env["action_dispatch.cookies_digest"] = "SHA256"
-    get :set_encrypted_cookie
-    cookies = @controller.send :cookies
-    assert_not_equal "bar", cookies[:foo]
-    assert_equal "bar", cookies.encrypted[:foo]
-
-    sign_secret = @request.env["action_dispatch.key_generator"].generate_key(@request.env["action_dispatch.encrypted_signed_cookie_salt"])
-
-    sha1_verifier   = ActiveSupport::MessageVerifier.new(sign_secret, serializer: ActiveSupport::MessageEncryptor::NullSerializer, digest: "SHA1")
-    sha256_verifier = ActiveSupport::MessageVerifier.new(sign_secret, serializer: ActiveSupport::MessageEncryptor::NullSerializer, digest: "SHA256")
-
-    assert_raises(ActiveSupport::MessageVerifier::InvalidSignature) do
-      sha1_verifier.verify(cookies[:foo])
-    end
-
-    assert_nothing_raised do
-      sha256_verifier.verify(cookies[:foo])
-    end
-  end
-
   def test_encrypted_cookie_using_hybrid_serializer_can_migrate_marshal_dumped_value_to_json
     @request.env["action_dispatch.cookies_serializer"] = :hybrid
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
-    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
-    secret = key_generator.generate_key(encrypted_cookie_salt)
-    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
 
-    marshal_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: Marshal).encrypt_and_sign("bar")
-    @request.headers["Cookie"] = "foo=#{marshal_value}"
+    marshal_value = encryptor.encrypt_and_sign("bar")
+    @request.headers["Cookie"] = "foo=#{::Rack::Utils.escape marshal_value}"
 
     get :get_encrypted_cookie
 
@@ -616,40 +585,28 @@ class CookiesTest < ActionController::TestCase
     assert_not_equal "bar", cookies[:foo]
     assert_equal "bar", cookies.encrypted[:foo]
 
-    encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON)
-    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+    json_encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
+    assert_not_nil @response.cookies["foo"]
+    assert_equal "bar", json_encryptor.decrypt_and_verify(@response.cookies["foo"])
   end
 
   def test_encrypted_cookie_using_hybrid_serializer_can_read_from_json_dumped_value
     @request.env["action_dispatch.cookies_serializer"] = :hybrid
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
-    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
-    secret = key_generator.generate_key(encrypted_cookie_salt)
-    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
-    json_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON).encrypt_and_sign("bar")
-    @request.headers["Cookie"] = "foo=#{json_value}"
-
-    get :get_encrypted_cookie
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
 
-    cookies = @controller.send :cookies
-    assert_not_equal "bar", cookies[:foo]
-    assert_equal "bar", cookies.encrypted[:foo]
-
-    assert_nil @response.cookies["foo"]
-  end
-
-  def test_compat_encrypted_cookie_using_64_byte_key
-    # Cookie generated with 64 bytes secret
-    message = ["566d4e75536d686e633246564e6b493062557079626c566d51574d30515430394c53315665564a694e4563786555744f57537454576b396a5a31566a626e52525054303d2d2d34663234333330623130623261306163363562316266323335396164666364613564643134623131"].pack("H*")
-    @request.headers["Cookie"] = "foo=#{message}"
+    json_value = encryptor.encrypt_and_sign("bar")
+    @request.headers["Cookie"] = "foo=#{::Rack::Utils.escape json_value}"
 
     get :get_encrypted_cookie
 
     cookies = @controller.send :cookies
     assert_not_equal "bar", cookies[:foo]
     assert_equal "bar", cookies.encrypted[:foo]
+
     assert_nil @response.cookies["foo"]
   end
 
@@ -813,10 +770,10 @@ class CookiesTest < ActionController::TestCase
 
     assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_cookie_salt"])
-    sign_secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_signed_cookie_salt"])
-    encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret)
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
     assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
   end
 
@@ -842,8 +799,6 @@ class CookiesTest < ActionController::TestCase
     @request.env["action_dispatch.cookies_serializer"] = :json
     @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
     @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
-    @request.env["action_dispatch.encrypted_cookie_salt"] = "4433796b79d99a7735553e316522acee"
-    @request.env["action_dispatch.encrypted_signed_cookie_salt"] = "00646eb40062e1b1deff205a27cd30f9"
 
     legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate("bar")
 
@@ -852,10 +807,10 @@ class CookiesTest < ActionController::TestCase
 
     assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_cookie_salt"])
-    sign_secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_signed_cookie_salt"])
-    encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON)
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
     assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
   end
 
@@ -881,8 +836,6 @@ class CookiesTest < ActionController::TestCase
     @request.env["action_dispatch.cookies_serializer"] = :hybrid
     @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
     @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
-    @request.env["action_dispatch.encrypted_cookie_salt"] = "4433796b79d99a7735553e316522acee"
-    @request.env["action_dispatch.encrypted_signed_cookie_salt"] = "00646eb40062e1b1deff205a27cd30f9"
 
     legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33", serializer: JSON).generate("bar")
 
@@ -891,10 +844,10 @@ class CookiesTest < ActionController::TestCase
 
     assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_cookie_salt"])
-    sign_secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_signed_cookie_salt"])
-    encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON)
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
     assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
   end
 
@@ -920,8 +873,6 @@ class CookiesTest < ActionController::TestCase
     @request.env["action_dispatch.cookies_serializer"] = :hybrid
     @request.env["action_dispatch.secret_token"] = "b3c631c314c0bbca50c1b2843150fe33"
     @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
-    @request.env["action_dispatch.encrypted_cookie_salt"] = "4433796b79d99a7735553e316522acee"
-    @request.env["action_dispatch.encrypted_signed_cookie_salt"] = "00646eb40062e1b1deff205a27cd30f9"
 
     legacy_value = ActiveSupport::MessageVerifier.new("b3c631c314c0bbca50c1b2843150fe33").generate("bar")
 
@@ -930,10 +881,10 @@ class CookiesTest < ActionController::TestCase
 
     assert_equal "bar", @controller.send(:cookies).encrypted[:foo]
 
-    key_generator = @request.env["action_dispatch.key_generator"]
-    secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_cookie_salt"])
-    sign_secret = key_generator.generate_key(@request.env["action_dispatch.encrypted_signed_cookie_salt"])
-    encryptor = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON)
+    cipher = "aes-256-gcm"
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: JSON)
     assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
   end
 
@@ -959,6 +910,89 @@ class CookiesTest < ActionController::TestCase
     assert_nil @response.cookies["foo"]
   end
 
+  def test_legacy_hmac_aes_cbc_encrypted_marshal_cookie_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
+    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
+    secret = key_generator.generate_key(encrypted_cookie_salt)
+    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
+    marshal_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: Marshal).encrypt_and_sign("bar")
+
+    @request.headers["Cookie"] = "foo=#{marshal_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    aead_cipher = "aes-256-gcm"
+    aead_salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    aead_secret = key_generator.generate_key(aead_salt)[0, ActiveSupport::MessageEncryptor.key_len(aead_cipher)]
+    aead_encryptor = ActiveSupport::MessageEncryptor.new(aead_secret, cipher: aead_cipher, serializer: Marshal)
+
+    assert_equal "bar", aead_encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_hmac_aes_cbc_encrypted_json_cookie_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.cookies_serializer"] = :json
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    key_generator = @request.env["action_dispatch.key_generator"]
+    encrypted_cookie_salt = @request.env["action_dispatch.encrypted_cookie_salt"]
+    encrypted_signed_cookie_salt = @request.env["action_dispatch.encrypted_signed_cookie_salt"]
+    secret = key_generator.generate_key(encrypted_cookie_salt)
+    sign_secret = key_generator.generate_key(encrypted_signed_cookie_salt)
+    marshal_value = ActiveSupport::MessageEncryptor.new(secret[0, ActiveSupport::MessageEncryptor.key_len], sign_secret, serializer: JSON).encrypt_and_sign("bar")
+
+    @request.headers["Cookie"] = "foo=#{marshal_value}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+
+    aead_cipher = "aes-256-gcm"
+    aead_salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    aead_secret = key_generator.generate_key(aead_salt)[0, ActiveSupport::MessageEncryptor.key_len(aead_cipher)]
+    aead_encryptor = ActiveSupport::MessageEncryptor.new(aead_secret, cipher: aead_cipher, serializer: JSON)
+
+    assert_equal "bar", aead_encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
+  def test_legacy_hmac_aes_cbc_encrypted_cookie_using_64_byte_key_is_upgraded_to_authenticated_encrypted_cookie
+    @request.env["action_dispatch.secret_key_base"] = "c3b95688f35581fad38df788add315ff"
+
+    @request.env["action_dispatch.encrypted_cookie_salt"] =
+      @request.env["action_dispatch.encrypted_signed_cookie_salt"] = SALT
+
+    # Cookie generated with 64 bytes secret
+    message = ["566d4e75536d686e633246564e6b493062557079626c566d51574d30515430394c53315665564a694e4563786555744f57537454576b396a5a31566a626e52525054303d2d2d34663234333330623130623261306163363562316266323335396164666364613564643134623131"].pack("H*")
+    @request.headers["Cookie"] = "foo=#{message}"
+
+    get :get_encrypted_cookie
+
+    cookies = @controller.send :cookies
+    assert_not_equal "bar", cookies[:foo]
+    assert_equal "bar", cookies.encrypted[:foo]
+    cipher = "aes-256-gcm"
+
+    salt = @request.env["action_dispatch.authenticated_encrypted_cookie_salt"]
+    secret = @request.env["action_dispatch.key_generator"].generate_key(salt)[0, ActiveSupport::MessageEncryptor.key_len(cipher)]
+    encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: Marshal)
+
+    assert_equal "bar", encryptor.decrypt_and_verify(@response.cookies["foo"])
+  end
+
   def test_cookie_with_all_domain_option
     get :set_cookie_with_domain
     assert_response :success