mirror of
https://github.com/rails/rails.git
synced 2022-11-09 12:12:34 -05:00
102 lines
3.4 KiB
Ruby
102 lines
3.4 KiB
Ruby
require 'openssl'
|
||
require 'base64'
|
||
|
||
module ActiveSupport
|
||
# MessageEncryptor is a simple way to encrypt values which get stored
|
||
# somewhere you don't trust.
|
||
#
|
||
# The cipher text and initialization vector are base64 encoded and returned
|
||
# to you.
|
||
#
|
||
# This can be used in situations similar to the <tt>MessageVerifier</tt>, but
|
||
# where you don't want users to be able to determine the value of the payload.
|
||
#
|
||
# key = OpenSSL::Digest::SHA256.new('password').digest # => "\x89\xE0\x156\xAC..."
|
||
# 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"
|
||
class MessageEncryptor
|
||
module NullSerializer #:nodoc:
|
||
def self.load(value)
|
||
value
|
||
end
|
||
|
||
def self.dump(value)
|
||
value
|
||
end
|
||
end
|
||
|
||
class InvalidMessage < StandardError; end
|
||
OpenSSLCipherError = OpenSSL::Cipher.const_defined?(:CipherError) ? OpenSSL::Cipher::CipherError : OpenSSL::CipherError
|
||
|
||
# Initialize a new MessageEncryptor. +secret+ must be at least as long as
|
||
# the cipher key size. For the default 'aes-256-cbc' cipher, this is 256
|
||
# bits. If you are using a user-entered secret, you can generate a suitable
|
||
# key with <tt>OpenSSL::Digest::SHA256.new(user_secret).digest</tt> or
|
||
# similar.
|
||
#
|
||
# Options:
|
||
# * <tt>:cipher</tt> - Cipher to use. Can be any cipher returned by
|
||
# <tt>OpenSSL::Cipher.ciphers</tt>. Default is 'aes-256-cbc'.
|
||
# * <tt>:serializer</tt> - Object serializer to use. Default is +Marshal+.
|
||
def initialize(secret, options = {})
|
||
@secret = secret
|
||
@cipher = options[:cipher] || 'aes-256-cbc'
|
||
@verifier = MessageVerifier.new(@secret, :serializer => NullSerializer)
|
||
@serializer = options[:serializer] || Marshal
|
||
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))
|
||
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))
|
||
end
|
||
|
||
private
|
||
|
||
def _encrypt(value)
|
||
cipher = new_cipher
|
||
# Rely on OpenSSL for the initialization vector
|
||
iv = cipher.random_iv
|
||
|
||
cipher.encrypt
|
||
cipher.key = @secret
|
||
cipher.iv = iv
|
||
|
||
encrypted_data = cipher.update(@serializer.dump(value))
|
||
encrypted_data << cipher.final
|
||
|
||
[encrypted_data, iv].map {|v| ::Base64.strict_encode64(v)}.join("--")
|
||
end
|
||
|
||
def _decrypt(encrypted_message)
|
||
cipher = new_cipher
|
||
encrypted_data, iv = encrypted_message.split("--").map {|v| ::Base64.decode64(v)}
|
||
|
||
cipher.decrypt
|
||
cipher.key = @secret
|
||
cipher.iv = iv
|
||
|
||
decrypted_data = cipher.update(encrypted_data)
|
||
decrypted_data << cipher.final
|
||
|
||
@serializer.load(decrypted_data)
|
||
rescue OpenSSLCipherError, TypeError
|
||
raise InvalidMessage
|
||
end
|
||
|
||
def new_cipher
|
||
OpenSSL::Cipher::Cipher.new(@cipher)
|
||
end
|
||
|
||
def verifier
|
||
@verifier
|
||
end
|
||
end
|
||
end
|