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token_generator.rb
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token_generator.rb
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# Deprecate: Copied verbatim from Rails source, remove once we move to Rails 4 only.
require 'thread_safe'
require 'openssl'
require 'securerandom'
module Devise
class TokenGenerator
def initialize(key_generator, digest="SHA256")
@key_generator = key_generator
@digest = digest
end
def digest(klass, column, value)
value.present? && OpenSSL::HMAC.hexdigest(@digest, key_for(column), value.to_s)
end
def generate(klass, column)
key = key_for(column)
loop do
raw = Devise.friendly_token
enc = OpenSSL::HMAC.hexdigest(@digest, key, raw)
break [raw, enc] unless klass.to_adapter.find_first({ column => enc })
end
end
private
def key_for(column)
@key_generator.generate_key("Devise #{column}")
end
end
# KeyGenerator is a simple wrapper around OpenSSL's implementation of PBKDF2
# It can be used to derive a number of keys for various purposes from a given secret.
# This lets Rails applications have a single secure secret, but avoid reusing that
# key in multiple incompatible contexts.
class KeyGenerator
def initialize(secret, options = {})
@secret = secret
# The default iterations are higher than required for our key derivation uses
# on the off chance someone uses this for password storage
@iterations = options[:iterations] || 2**16
end
# Returns a derived key suitable for use. The default key_size is chosen
# to be compatible with the default settings of ActiveSupport::MessageVerifier.
# i.e. OpenSSL::Digest::SHA1#block_length
def generate_key(salt, key_size=64)
OpenSSL::PKCS5.pbkdf2_hmac_sha1(@secret, salt, @iterations, key_size)
end
end
# CachingKeyGenerator is a wrapper around KeyGenerator which allows users to avoid
# re-executing the key generation process when it's called using the same salt and
# key_size
class CachingKeyGenerator
def initialize(key_generator)
@key_generator = key_generator
@cache_keys = ThreadSafe::Cache.new
end
# Returns a derived key suitable for use. The default key_size is chosen
# to be compatible with the default settings of ActiveSupport::MessageVerifier.
# i.e. OpenSSL::Digest::SHA1#block_length
def generate_key(salt, key_size=64)
@cache_keys["#{salt}#{key_size}"] ||= @key_generator.generate_key(salt, key_size)
end
end
end