diff options
Diffstat (limited to 'activesupport/lib/active_support/message_encryptor.rb')
| -rw-r--r-- | activesupport/lib/active_support/message_encryptor.rb | 85 |
1 files changed, 72 insertions, 13 deletions
diff --git a/activesupport/lib/active_support/message_encryptor.rb b/activesupport/lib/active_support/message_encryptor.rb index d5db2920b9..69c95e0622 100644 --- a/activesupport/lib/active_support/message_encryptor.rb +++ b/activesupport/lib/active_support/message_encryptor.rb @@ -2,8 +2,9 @@ require "openssl" require "base64" -require_relative "core_ext/array/extract_options" -require_relative "message_verifier" +require "active_support/core_ext/array/extract_options" +require "active_support/message_verifier" +require "active_support/messages/metadata" module ActiveSupport # MessageEncryptor is a simple way to encrypt values which get stored @@ -21,7 +22,65 @@ module ActiveSupport # crypt = ActiveSupport::MessageEncryptor.new(key) # => #<ActiveSupport::MessageEncryptor ...> # encrypted_data = crypt.encrypt_and_sign('my secret data') # => "NlFBTTMwOUV5UlA1QlNEN2xkY2d6eThYWWh..." # crypt.decrypt_and_verify(encrypted_data) # => "my secret data" + # + # === Confining messages to a specific purpose + # + # By default any message can be used throughout your app. But they can also be + # confined to a specific +:purpose+. + # + # token = crypt.encrypt_and_sign("this is the chair", purpose: :login) + # + # Then that same purpose must be passed when verifying to get the data back out: + # + # crypt.decrypt_and_verify(token, purpose: :login) # => "this is the chair" + # crypt.decrypt_and_verify(token, purpose: :shipping) # => nil + # crypt.decrypt_and_verify(token) # => nil + # + # Likewise, if a message has no purpose it won't be returned when verifying with + # a specific purpose. + # + # token = crypt.encrypt_and_sign("the conversation is lively") + # crypt.decrypt_and_verify(token, purpose: :scare_tactics) # => nil + # crypt.decrypt_and_verify(token) # => "the conversation is lively" + # + # === Making messages expire + # + # By default messages last forever and verifying one year from now will still + # return the original value. But messages can be set to expire at a given + # time with +:expires_in+ or +:expires_at+. + # + # crypt.encrypt_and_sign(parcel, expires_in: 1.month) + # crypt.encrypt_and_sign(doowad, expires_at: Time.now.end_of_year) + # + # Then the messages can be verified and returned upto the expire time. + # Thereafter, verifying returns +nil+. + # + # === Rotating keys + # + # MessageEncryptor also supports rotating out old configurations by falling + # back to a stack of encryptors. Call `rotate` to build and add an encryptor + # so `decrypt_and_verify` will also try the fallback. + # + # By default any rotated encryptors use the values of the primary + # encryptor unless specified otherwise. + # + # You'd give your encryptor the new defaults: + # + # crypt = ActiveSupport::MessageEncryptor.new(@secret, cipher: "aes-256-gcm") + # + # Then gradually rotate the old values out by adding them as fallbacks. Any message + # generated with the old values will then work until the rotation is removed. + # + # crypt.rotate old_secret # Fallback to an old secret instead of @secret. + # crypt.rotate cipher: "aes-256-cbc" # Fallback to an old cipher instead of aes-256-gcm. + # + # Though if both the secret and the cipher was changed at the same time, + # the above should be combined into: + # + # crypt.rotate old_secret, cipher: "aes-256-cbc" class MessageEncryptor + prepend Messages::Rotator::Encryptor + class << self attr_accessor :use_authenticated_message_encryption #:nodoc: @@ -86,15 +145,15 @@ module ActiveSupport end # Encrypt and sign a message. We need to sign the message in order to avoid - # padding attacks. Reference: http://www.limited-entropy.com/padding-oracle-attacks. - def encrypt_and_sign(value) - verifier.generate(_encrypt(value)) + # padding attacks. Reference: https://www.limited-entropy.com/padding-oracle-attacks/. + def encrypt_and_sign(value, expires_at: nil, expires_in: nil, purpose: nil) + verifier.generate(_encrypt(value, expires_at: expires_at, expires_in: expires_in, purpose: purpose)) end # Decrypt and verify a message. We need to verify the message in order to - # avoid padding attacks. Reference: http://www.limited-entropy.com/padding-oracle-attacks. - def decrypt_and_verify(value) - _decrypt(verifier.verify(value)) + # avoid padding attacks. Reference: https://www.limited-entropy.com/padding-oracle-attacks/. + def decrypt_and_verify(data, purpose: nil, **) + _decrypt(verifier.verify(data), purpose) end # Given a cipher, returns the key length of the cipher to help generate the key of desired size @@ -103,8 +162,7 @@ module ActiveSupport end private - - def _encrypt(value) + def _encrypt(value, **metadata_options) cipher = new_cipher cipher.encrypt cipher.key = @secret @@ -113,7 +171,7 @@ module ActiveSupport iv = cipher.random_iv cipher.auth_data = "" if aead_mode? - encrypted_data = cipher.update(@serializer.dump(value)) + encrypted_data = cipher.update(Messages::Metadata.wrap(@serializer.dump(value), metadata_options)) encrypted_data << cipher.final blob = "#{::Base64.strict_encode64 encrypted_data}--#{::Base64.strict_encode64 iv}" @@ -121,7 +179,7 @@ module ActiveSupport blob end - def _decrypt(encrypted_message) + def _decrypt(encrypted_message, purpose) cipher = new_cipher encrypted_data, iv, auth_tag = encrypted_message.split("--".freeze).map { |v| ::Base64.strict_decode64(v) } @@ -141,7 +199,8 @@ module ActiveSupport decrypted_data = cipher.update(encrypted_data) decrypted_data << cipher.final - @serializer.load(decrypted_data) + message = Messages::Metadata.verify(decrypted_data, purpose) + @serializer.load(message) if message rescue OpenSSLCipherError, TypeError, ArgumentError raise InvalidMessage end |