fedibird-fe/app/validators/email_mx_validator.rb
Claire 051efed5ed
Bypass MX validation for explicitly allowed domains (#15930)
* Bypass MX validation for explicitly allowed domains

This spares some lookups and prevent issues in some edge cases with
local domains.

* Add tests

* Fix test
2021-03-19 23:48:47 +01:00

63 lines
1.5 KiB
Ruby

# frozen_string_literal: true
require 'resolv'
class EmailMxValidator < ActiveModel::Validator
def validate(user)
return if user.email.blank?
domain = get_domain(user.email)
if domain.blank?
user.errors.add(:email, :invalid)
elsif !on_allowlist?(domain)
ips, hostnames = resolve_mx(domain)
if ips.empty?
user.errors.add(:email, :unreachable)
elsif on_blacklist?(hostnames + ips)
user.errors.add(:email, :blocked)
end
end
end
private
def get_domain(value)
_, domain = value.split('@', 2)
return nil if domain.nil?
TagManager.instance.normalize_domain(domain)
rescue Addressable::URI::InvalidURIError
nil
end
def on_allowlist?(domain)
return false if Rails.configuration.x.email_domains_whitelist.blank?
Rails.configuration.x.email_domains_whitelist.include?(domain)
end
def resolve_mx(domain)
hostnames = []
ips = []
Resolv::DNS.open do |dns|
dns.timeouts = 5
hostnames = dns.getresources(domain, Resolv::DNS::Resource::IN::MX).to_a.map { |e| e.exchange.to_s }
([domain] + hostnames).uniq.each do |hostname|
ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::A).to_a.map { |e| e.address.to_s })
ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::AAAA).to_a.map { |e| e.address.to_s })
end
end
[ips, hostnames]
end
def on_blacklist?(values)
EmailDomainBlock.where(domain: values.uniq).any?
end
end