From 5a3ba63d9abad86b7f6dd36a92cfaf722e52760b Mon Sep 17 00:00:00 2001 From: Michael Coyne Date: Thu, 23 Feb 2017 13:54:17 -0500 Subject: 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. --- .../lib/action_dispatch/middleware/cookies.rb | 51 ++++++++++++++++++++-- actionpack/lib/action_dispatch/railtie.rb | 3 ++ 2 files changed, 51 insertions(+), 3 deletions(-) (limited to 'actionpack/lib') diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb index e565c03a8a..c0dda1bba5 100644 --- a/actionpack/lib/action_dispatch/middleware/cookies.rb +++ b/actionpack/lib/action_dispatch/middleware/cookies.rb @@ -43,6 +43,10 @@ module ActionDispatch get_header Cookies::ENCRYPTED_SIGNED_COOKIE_SALT end + def authenticated_encrypted_cookie_salt + get_header Cookies::AUTHENTICATED_ENCRYPTED_COOKIE_SALT + end + def secret_token get_header Cookies::SECRET_TOKEN end @@ -149,6 +153,7 @@ module ActionDispatch SIGNED_COOKIE_SALT = "action_dispatch.signed_cookie_salt".freeze ENCRYPTED_COOKIE_SALT = "action_dispatch.encrypted_cookie_salt".freeze ENCRYPTED_SIGNED_COOKIE_SALT = "action_dispatch.encrypted_signed_cookie_salt".freeze + AUTHENTICATED_ENCRYPTED_COOKIE_SALT = "action_dispatch.authenticated_encrypted_cookie_salt".freeze SECRET_TOKEN = "action_dispatch.secret_token".freeze SECRET_KEY_BASE = "action_dispatch.secret_key_base".freeze COOKIES_SERIALIZER = "action_dispatch.cookies_serializer".freeze @@ -207,6 +212,9 @@ module ActionDispatch # If +secrets.secret_key_base+ and +secrets.secret_token+ (deprecated) are both set, # legacy cookies signed with the old key generator will be transparently upgraded. # + # If +config.action_dispatch.encrypted_cookie_salt+ and +config.action_dispatch.encrypted_signed_cookie_salt+ + # are both set, legacy cookies encrypted with HMAC AES-256-CBC will be transparently upgraded. + # # This jar requires that you set a suitable secret for the verification on your app's +secrets.secret_key_base+. # # Example: @@ -219,6 +227,8 @@ module ActionDispatch @encrypted ||= if upgrade_legacy_signed_cookies? UpgradeLegacyEncryptedCookieJar.new(self) + elsif upgrade_legacy_hmac_aes_cbc_cookies? + UpgradeLegacyHmacAesCbcCookieJar.new(self) else EncryptedCookieJar.new(self) end @@ -240,6 +250,13 @@ module ActionDispatch def upgrade_legacy_signed_cookies? request.secret_token.present? && request.secret_key_base.present? end + + def upgrade_legacy_hmac_aes_cbc_cookies? + request.secret_key_base.present? && + request.authenticated_encrypted_cookie_salt.present? && + request.encrypted_signed_cookie_salt.present? && + request.encrypted_cookie_salt.present? + end end # Passing the ActiveSupport::MessageEncryptor::NullSerializer downstream @@ -576,9 +593,11 @@ module ActionDispatch "Read the upgrade documentation to learn more about this new config option." end - secret = key_generator.generate_key(request.encrypted_cookie_salt || "")[0, ActiveSupport::MessageEncryptor.key_len] - sign_secret = key_generator.generate_key(request.encrypted_signed_cookie_salt || "") - @encryptor = ActiveSupport::MessageEncryptor.new(secret, sign_secret, digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer) + cipher = "aes-256-gcm" + key_len = ActiveSupport::MessageEncryptor.key_len(cipher) + secret = key_generator.generate_key(request.authenticated_encrypted_cookie_salt || "")[0, key_len] + + @encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: ActiveSupport::MessageEncryptor::NullSerializer) end private @@ -603,6 +622,32 @@ module ActionDispatch include VerifyAndUpgradeLegacySignedMessage end + # UpgradeLegacyHmacAesCbcCookieJar is used by ActionDispatch::Session::CookieStore + # to upgrade cookies encrypted with AES-256-CBC with HMAC to AES-256-GCM + class UpgradeLegacyHmacAesCbcCookieJar < EncryptedCookieJar + def initialize(parent_jar) + super + + secret = key_generator.generate_key(request.encrypted_cookie_salt || "")[0, ActiveSupport::MessageEncryptor.key_len] + sign_secret = key_generator.generate_key(request.encrypted_signed_cookie_salt || "") + + @legacy_encryptor = ActiveSupport::MessageEncryptor.new(secret, sign_secret, digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer) + end + + def decrypt_and_verify_legacy_encrypted_message(name, signed_message) + deserialize(name, @legacy_encryptor.decrypt_and_verify(signed_message)).tap do |value| + self[name] = { value: value } + end + rescue ActiveSupport::MessageVerifier::InvalidSignature, ActiveSupport::MessageEncryptor::InvalidMessage + nil + end + + private + def parse(name, signed_message) + super || decrypt_and_verify_legacy_encrypted_message(name, signed_message) + end + end + def initialize(app) @app = app end diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb index 16a18a7f25..7662e164b8 100644 --- a/actionpack/lib/action_dispatch/railtie.rb +++ b/actionpack/lib/action_dispatch/railtie.rb @@ -16,6 +16,7 @@ module ActionDispatch config.action_dispatch.signed_cookie_salt = "signed cookie" config.action_dispatch.encrypted_cookie_salt = "encrypted cookie" config.action_dispatch.encrypted_signed_cookie_salt = "signed encrypted cookie" + config.action_dispatch.use_authenticated_cookie_encryption = false config.action_dispatch.perform_deep_munge = true config.action_dispatch.default_headers = { @@ -36,6 +37,8 @@ module ActionDispatch ActionDispatch::ExceptionWrapper.rescue_responses.merge!(config.action_dispatch.rescue_responses) ActionDispatch::ExceptionWrapper.rescue_templates.merge!(config.action_dispatch.rescue_templates) + config.action_dispatch.authenticated_encrypted_cookie_salt = "authenticated encrypted cookie" if config.action_dispatch.use_authenticated_cookie_encryption + config.action_dispatch.always_write_cookie = Rails.env.development? if config.action_dispatch.always_write_cookie.nil? ActionDispatch::Cookies::CookieJar.always_write_cookie = config.action_dispatch.always_write_cookie -- cgit v1.2.3