From a5a00d7f7adff5e0afbd23ac1e1b16120137509a Mon Sep 17 00:00:00 2001 From: Claire Date: Tue, 24 Jan 2023 20:18:41 +0100 Subject: [PATCH] Fix email with empty domain name labels passing validation (#23246) * Fix email with empty domain name labels passing validation `EmailMxValidator` would allow empty labels because `Resolv::DNS` is particularly lenient about them, but the email would be invalid and unusable. * Add tests --- app/validators/email_mx_validator.rb | 2 ++ spec/validators/email_mx_validator_spec.rb | 27 ++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/app/validators/email_mx_validator.rb b/app/validators/email_mx_validator.rb index 20f2fd37c6..19c57bdf66 100644 --- a/app/validators/email_mx_validator.rb +++ b/app/validators/email_mx_validator.rb @@ -10,6 +10,8 @@ class EmailMxValidator < ActiveModel::Validator if domain.blank? user.errors.add(:email, :invalid) + elsif domain.include?('..') + user.errors.add(:email, :invalid) elsif !on_allowlist?(domain) resolved_ips, resolved_domains = resolve_mx(domain) diff --git a/spec/validators/email_mx_validator_spec.rb b/spec/validators/email_mx_validator_spec.rb index 4feedd0c7f..6640d6058e 100644 --- a/spec/validators/email_mx_validator_spec.rb +++ b/spec/validators/email_mx_validator_spec.rb @@ -28,6 +28,33 @@ describe EmailMxValidator do end end + it 'adds no error if there are DNS records for the e-mail domain' do + resolver = double + + allow(resolver).to receive(:getresources).with('example.com', Resolv::DNS::Resource::IN::MX).and_return([]) + allow(resolver).to receive(:getresources).with('example.com', Resolv::DNS::Resource::IN::A).and_return([Resolv::DNS::Resource::IN::A.new('192.0.2.42')]) + allow(resolver).to receive(:getresources).with('example.com', Resolv::DNS::Resource::IN::AAAA).and_return([]) + allow(resolver).to receive(:timeouts=).and_return(nil) + allow(Resolv::DNS).to receive(:open).and_yield(resolver) + + subject.validate(user) + expect(user.errors).not_to have_received(:add) + end + + it 'adds an error if the email domain name contains empty labels' do + resolver = double + + allow(resolver).to receive(:getresources).with('example..com', Resolv::DNS::Resource::IN::MX).and_return([]) + allow(resolver).to receive(:getresources).with('example..com', Resolv::DNS::Resource::IN::A).and_return([Resolv::DNS::Resource::IN::A.new('192.0.2.42')]) + allow(resolver).to receive(:getresources).with('example..com', Resolv::DNS::Resource::IN::AAAA).and_return([]) + allow(resolver).to receive(:timeouts=).and_return(nil) + allow(Resolv::DNS).to receive(:open).and_yield(resolver) + + user = double(email: 'foo@example..com', sign_up_ip: '1.2.3.4', errors: double(add: nil)) + subject.validate(user) + expect(user.errors).to have_received(:add) + end + it 'adds an error if there are no DNS records for the e-mail domain' do resolver = double