From 8b0af54bbe5ab8b598e980013dd53a50d819b636 Mon Sep 17 00:00:00 2001 From: Michael Coyne Date: Sat, 23 Sep 2017 17:18:01 -0400 Subject: Add key rotation cookies middleware Using the action_dispatch.cookies_rotations interface, key rotation is now possible with cookies. Thus the secret_key_base as well as salts, ciphers, and digests, can be rotated without expiring sessions. --- .../lib/action_dispatch/middleware/cookies.rb | 182 ++++++++++----------- 1 file changed, 82 insertions(+), 100 deletions(-) (limited to 'actionpack/lib/action_dispatch/middleware/cookies.rb') diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb index 845df500d8..b3831649a8 100644 --- a/actionpack/lib/action_dispatch/middleware/cookies.rb +++ b/actionpack/lib/action_dispatch/middleware/cookies.rb @@ -49,6 +49,18 @@ module ActionDispatch get_header Cookies::AUTHENTICATED_ENCRYPTED_COOKIE_SALT end + def use_authenticated_cookie_encryption + get_header Cookies::USE_AUTHENTICATED_COOKIE_ENCRYPTION + end + + def encrypted_cookie_cipher + get_header Cookies::ENCRYPTED_COOKIE_CIPHER + end + + def signed_cookie_digest + get_header Cookies::SIGNED_COOKIE_DIGEST + end + def secret_token get_header Cookies::SECRET_TOKEN end @@ -64,6 +76,11 @@ module ActionDispatch def cookies_digest get_header Cookies::COOKIES_DIGEST end + + def cookies_rotations + get_header Cookies::COOKIES_ROTATIONS + end + # :startdoc: end @@ -157,10 +174,14 @@ module ActionDispatch 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 + USE_AUTHENTICATED_COOKIE_ENCRYPTION = "action_dispatch.use_authenticated_cookie_encryption".freeze + ENCRYPTED_COOKIE_CIPHER = "action_dispatch.encrypted_cookie_cipher".freeze + SIGNED_COOKIE_DIGEST = "action_dispatch.signed_cookie_digest".freeze SECRET_TOKEN = "action_dispatch.secret_token".freeze SECRET_KEY_BASE = "action_dispatch.secret_key_base".freeze COOKIES_SERIALIZER = "action_dispatch.cookies_serializer".freeze COOKIES_DIGEST = "action_dispatch.cookies_digest".freeze + COOKIES_ROTATIONS = "action_dispatch.cookies_rotations".freeze # Cookies can typically store 4096 bytes. MAX_COOKIE_SIZE = 4096 @@ -201,12 +222,7 @@ module ActionDispatch # # cookies.signed[:discount] # => 45 def signed - @signed ||= - if upgrade_legacy_signed_cookies? - UpgradeLegacySignedCookieJar.new(self) - else - SignedCookieJar.new(self) - end + @signed ||= SignedKeyRotatingCookieJar.new(self) end # Returns a jar that'll automatically encrypt cookie values before sending them to the client and will decrypt them for read. @@ -223,18 +239,11 @@ module ActionDispatch # Example: # # cookies.encrypted[:discount] = 45 - # # => Set-Cookie: discount=ZS9ZZ1R4cG1pcUJ1bm80anhQang3dz09LS1mbDZDSU5scGdOT3ltQ2dTdlhSdWpRPT0%3D--ab54663c9f4e3bc340c790d6d2b71e92f5b60315; path=/ + # # => Set-Cookie: discount=DIQ7fw==--K3n//8vvnSbGq9dA--7Xh91HfLpwzbj1czhBiwOg==; path=/ # # cookies.encrypted[:discount] # => 45 def encrypted - @encrypted ||= - if upgrade_legacy_signed_cookies? - UpgradeLegacyEncryptedCookieJar.new(self) - elsif upgrade_legacy_hmac_aes_cbc_cookies? - UpgradeLegacyHmacAesCbcCookieJar.new(self) - else - EncryptedCookieJar.new(self) - end + @encrypted ||= EncryptedKeyRotatingCookieJar.new(self) end # Returns the +signed+ or +encrypted+ jar, preferring +encrypted+ if +secret_key_base+ is set. @@ -256,33 +265,17 @@ module ActionDispatch 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? + request.encrypted_cookie_salt.present? && + request.use_authenticated_cookie_encryption end - end - - # Passing the ActiveSupport::MessageEncryptor::NullSerializer downstream - # to the Message{Encryptor,Verifier} allows us to handle the - # (de)serialization step within the cookie jar, which gives us the - # opportunity to detect and migrate legacy cookies. - module VerifyAndUpgradeLegacySignedMessage # :nodoc: - def initialize(*args) - super - @legacy_verifier = ActiveSupport::MessageVerifier.new(request.secret_token, serializer: ActiveSupport::MessageEncryptor::NullSerializer) - end - def verify_and_upgrade_legacy_signed_message(name, signed_message) - deserialize(name, @legacy_verifier.verify(signed_message)).tap do |value| - self[name] = { value: value } + def encrypted_cookie_cipher + request.encrypted_cookie_cipher || "aes-256-gcm" end - rescue ActiveSupport::MessageVerifier::InvalidSignature - nil - end - private - def parse(name, signed_message) - super || verify_and_upgrade_legacy_signed_message(name, signed_message) + def signed_cookie_digest + request.signed_cookie_digest || "SHA1" end end @@ -524,6 +517,7 @@ module ActionDispatch module SerializedCookieJars # :nodoc: MARSHAL_SIGNATURE = "\x04\x08".freeze + SERIALIZER = ActiveSupport::MessageEncryptor::NullSerializer protected def needs_migration?(value) @@ -534,12 +528,16 @@ module ActionDispatch serializer.dump(value) end - def deserialize(name, value) + def deserialize(name) + rotate = false + value = yield -> { rotate = true } + if value - if needs_migration?(value) - Marshal.load(value).tap do |v| - self[name] = { value: v } - end + case + when needs_migration?(value) + self[name] = Marshal.load(value) + when rotate + self[name] = serializer.load(value) else serializer.load(value) end @@ -561,24 +559,31 @@ module ActionDispatch def digest request.cookies_digest || "SHA1" end - - def key_generator - request.key_generator - end end - class SignedCookieJar < AbstractCookieJar # :nodoc: + class SignedKeyRotatingCookieJar < AbstractCookieJar # :nodoc: include SerializedCookieJars def initialize(parent_jar) super - secret = key_generator.generate_key(request.signed_cookie_salt) - @verifier = ActiveSupport::MessageVerifier.new(secret, digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer) + + secret = request.key_generator.generate_key(request.signed_cookie_salt) + @verifier = ActiveSupport::MessageVerifier.new(secret, digest: signed_cookie_digest, serializer: SERIALIZER) + + request.cookies_rotations.signed.each do |rotation_options| + @verifier.rotate serializer: SERIALIZER, **rotation_options + end + + if upgrade_legacy_signed_cookies? + @verifier.rotate raw_key: request.secret_token, serializer: SERIALIZER + end end private def parse(name, signed_message) - deserialize name, @verifier.verified(signed_message) + deserialize(name) do |rotate| + @verifier.verified(signed_message, on_rotation: rotate) + end end def commit(options) @@ -588,37 +593,38 @@ module ActionDispatch end end - # UpgradeLegacySignedCookieJar is used instead of SignedCookieJar if - # secrets.secret_token and secret_key_base are both set. It reads - # legacy cookies signed with the old dummy key generator and signs and - # re-saves them using the new key generator to provide a smooth upgrade path. - class UpgradeLegacySignedCookieJar < SignedCookieJar #:nodoc: - include VerifyAndUpgradeLegacySignedMessage - end - - class EncryptedCookieJar < AbstractCookieJar # :nodoc: + class EncryptedKeyRotatingCookieJar < AbstractCookieJar # :nodoc: include SerializedCookieJars def initialize(parent_jar) super - if ActiveSupport::LegacyKeyGenerator === key_generator - raise "You didn't set secret_key_base, which is required for this cookie jar. " \ - "Read the upgrade documentation to learn more about this new config option." + key_len = ActiveSupport::MessageEncryptor.key_len(encrypted_cookie_cipher) + secret = request.key_generator.generate_key(request.authenticated_encrypted_cookie_salt, key_len) + @encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: encrypted_cookie_cipher, serializer: SERIALIZER) + + request.cookies_rotations.encrypted.each do |rotation_options| + @encryptor.rotate serializer: SERIALIZER, **rotation_options end - cipher = "aes-256-gcm" - key_len = ActiveSupport::MessageEncryptor.key_len(cipher) - secret = key_generator.generate_key(request.authenticated_encrypted_cookie_salt || "")[0, key_len] + if upgrade_legacy_hmac_aes_cbc_cookies? + @encryptor.rotate \ + key_generator: request.key_generator, salt: request.encrypted_cookie_salt, signed_salt: request.encrypted_signed_cookie_salt, + cipher: "aes-256-cbc", digest: digest, serializer: SERIALIZER + end - @encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: ActiveSupport::MessageEncryptor::NullSerializer) + if upgrade_legacy_signed_cookies? + @legacy_verifier = ActiveSupport::MessageVerifier.new(request.secret_token, digest: digest, serializer: SERIALIZER) + end end private def parse(name, encrypted_message) - deserialize name, @encryptor.decrypt_and_verify(encrypted_message) - rescue ActiveSupport::MessageVerifier::InvalidSignature, ActiveSupport::MessageEncryptor::InvalidMessage - nil + deserialize(name) do |rotate| + @encryptor.decrypt_and_verify(encrypted_message, on_rotation: rotate) + end + rescue ActiveSupport::MessageEncryptor::InvalidMessage, ActiveSupport::MessageVerifier::InvalidSignature + parse_legacy_signed_message(name, encrypted_message) end def commit(options) @@ -626,39 +632,15 @@ module ActionDispatch raise CookieOverflow if options[:value].bytesize > MAX_COOKIE_SIZE end - end - # UpgradeLegacyEncryptedCookieJar is used by ActionDispatch::Session::CookieStore - # instead of EncryptedCookieJar if secrets.secret_token and secret_key_base - # are both set. It reads legacy cookies signed with the old dummy key generator and - # encrypts and re-saves them using the new key generator to provide a smooth upgrade path. - class UpgradeLegacyEncryptedCookieJar < EncryptedCookieJar #:nodoc: - include VerifyAndUpgradeLegacySignedMessage - end + def parse_legacy_signed_message(name, legacy_signed_message) + if defined?(@legacy_verifier) + deserialize(name) do |rotate| + rotate.call - # 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, cipher: "aes-256-cbc", 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) + @legacy_verifier.verified(legacy_signed_message) + end + end end end -- cgit v1.2.3