module Gitlab # The +otp_key_base+ param is used to encrypt the User#otp_secret attribute. # # When +otp_key_base+ is changed, it invalidates the current encrypted values # of User#otp_secret. This class can be used to decrypt all the values with # the old key, encrypt them with the new key, and and update the database # with the new values. # # For persistence between runs, a CSV file is used with the following columns: # # user_id, old_value, new_value # # Only the encrypted values are stored in this file. # # As users may have their 2FA settings changed at any time, this is only # guaranteed to be safe if run offline. class OtpKeyRotator HEADERS = %w[user_id old_value new_value].freeze attr_reader :filename # Create a new rotator. +filename+ is used to store values by +calculate!+, # and to update the database with new and old values in +apply!+ and # +rollback!+, respectively. def initialize(filename) @filename = filename end def rotate!(old_key:, new_key:) old_key ||= Gitlab::Application.secrets.otp_key_base raise ArgumentError.new("Old key is the same as the new key") if old_key == new_key raise ArgumentError.new("New key is too short! Must be 256 bits") if new_key.size < 64 write_csv do |csv| ActiveRecord::Base.transaction do User.with_two_factor.in_batches do |relation| # rubocop: disable Cop/InBatches rows = relation.pluck(:id, :encrypted_otp_secret, :encrypted_otp_secret_iv, :encrypted_otp_secret_salt) rows.each do |row| user = %i[id ciphertext iv salt].zip(row).to_h new_value = reencrypt(user, old_key, new_key) User.where(id: user[:id]).update_all(encrypted_otp_secret: new_value) csv << [user[:id], user[:ciphertext], new_value] end end end end end def rollback! ActiveRecord::Base.transaction do CSV.foreach(filename, headers: HEADERS, return_headers: false) do |row| User.where(id: row['user_id']).update_all(encrypted_otp_secret: row['old_value']) end end end private attr_reader :old_key, :new_key def otp_secret_settings @otp_secret_settings ||= User.encrypted_attributes[:otp_secret] end def reencrypt(user, old_key, new_key) original = user[:ciphertext].unpack("m").join opts = { iv: user[:iv].unpack("m").join, salt: user[:salt].unpack("m").join, algorithm: otp_secret_settings[:algorithm], insecure_mode: otp_secret_settings[:insecure_mode] } decrypted = Encryptor.decrypt(original, opts.merge(key: old_key)) encrypted = Encryptor.encrypt(decrypted, opts.merge(key: new_key)) [encrypted].pack("m") end def write_csv(&blk) File.open(filename, "w") do |file| yield CSV.new(file, headers: HEADERS, write_headers: false) end end end end