Improve Omniauth security

app/interactors/authenticate_user_with_omniauth.rb

@@ -9,6 +9,8 @@ class AuthenticateUserWithOmniauth
     ActiveRecord::Base.transaction do
       build_user
       build_user_omniauth
+      validity_check
+      security_check
       save_records
     end
   end
@@ -42,6 +44,18 @@ private
     end
   end
 
+  def validity_check
+    return if context.user_omniauth.user == context.user
+
+    context.fail! user: nil, user_omniauth: nil
+  end
+
+  def security_check
+    return unless context.user.persisted? && context.user_omniauth.new_record?
+
+    context.fail! user: nil, user_omniauth: nil
+  end
+
   def save_records
     return if context.user.save &&
               context.user_omniauth.save