masto-fe/app/validators/email_mx_validator.rb
ThibG 8d217d7231
Improve email address validation (#14565)
* Increase DNS timeout from 1 second to 5 seconds for MX check

1 seconds is rather short when using a recursive DNS resolver which
hasn't got a cached result already available. Use 5 seconds instead,
which is the timeout value we use for outgoing HTTP queries.

* Add more precise error messages for invalid e-mail addresses
2020-08-12 12:40:25 +02:00

54 lines
1.3 KiB
Ruby

# frozen_string_literal: true
require 'resolv'
class EmailMxValidator < ActiveModel::Validator
def validate(user)
domain = get_domain(user.email)
if domain.nil?
user.errors.add(:email, I18n.t('users.invalid_email'))
else
ips, hostnames = resolve_mx(domain)
if ips.empty?
user.errors.add(:email, I18n.t('users.invalid_email_mx'))
elsif on_blacklist?(hostnames + ips)
user.errors.add(:email, I18n.t('users.blocked_email_provider'))
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 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