Validate that e-mail resolves with MX and it's not blacklisted (#7631)

Original patch by @j-a4
tootsuite · May 27, 2018 · 63c7b9157274f57c496399a1a5c728b32415034c · 63c7b91
1 parent 182bdbc
commit 63c7b9157274f57c496399a1a5c728b32415034c
Unified Split

Showing with 26 additions and 0 deletions.

+1 −0 app/models/user.rb

+25 −0 app/validators/email_mx_validator.rb
diff --git 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
@@ -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