From 63c7b9157274f57c496399a1a5c728b32415034c Mon Sep 17 00:00:00 2001 From: Eugen Rochko Date: Sun, 27 May 2018 04:58:08 +0200 Subject: [PATCH] Validate that e-mail resolves with MX and it's not blacklisted (#7631) Original patch by @j-a4 --- app/models/user.rb | 1 + app/validators/email_mx_validator.rb | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) create mode 100644 app/validators/email_mx_validator.rb diff --git a/app/models/user.rb b/app/models/user.rb index cfbae58ed3..0becfa7e96 100644 --- a/app/models/user.rb +++ b/app/models/user.rb @@ -65,6 +65,7 @@ class User < ApplicationRecord validates :locale, inclusion: I18n.available_locales.map(&:to_s), if: :locale? validates_with BlacklistedEmailValidator, if: :email_changed? + validates_with EmailMxValidator, if: :email_changed? scope :recent, -> { order(id: :desc) } scope :admins, -> { where(admin: true) } diff --git a/app/validators/email_mx_validator.rb b/app/validators/email_mx_validator.rb new file mode 100644 index 0000000000..d4c7cc252a --- /dev/null +++ b/app/validators/email_mx_validator.rb @@ -0,0 +1,25 @@ +# frozen_string_literal: true + +require 'resolv' + +class EmailMxValidator < ActiveModel::Validator + def validate(user) + return if Rails.env.test? + user.errors.add(:email, I18n.t('users.invalid_email')) if invalid_mx?(user.email) + end + + private + + def invalid_mx?(value) + _, domain = value.split('@', 2) + + return true if domain.nil? + + records = Resolv::DNS.new.getresources(domain, Resolv::DNS::Resource::IN::MX).to_a.map { |e| e.exchange.to_s } + records.empty? || on_blacklist?(records) + end + + def on_blacklist?(values) + EmailDomainBlock.where(domain: values).any? + end +end