From 051efed5edd544b4f88c63a1038274ae2db30038 Mon Sep 17 00:00:00 2001
From: Claire <claire.github-309c@sitedethib.com>
Date: Fri, 19 Mar 2021 23:48:47 +0100
Subject: [PATCH] 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
---
app/validators/email_mx_validator.rb | 8 +++++++-
spec/models/user_spec.rb | 2 +-
spec/validators/email_mx_validator_spec.rb | 18 ++++++++++++++++++
3 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/app/validators/email_mx_validator.rb b/app/validators/email_mx_validator.rb
index 9f70a1469a..dceef50290 100644
--- a/app/validators/email_mx_validator.rb
+++ b/app/validators/email_mx_validator.rb
@@ -10,7 +10,7 @@ class EmailMxValidator < ActiveModel::Validator
if domain.blank?
user.errors.add(:email, :invalid)
- else
+ elsif !on_allowlist?(domain)
ips, hostnames = resolve_mx(domain)
if ips.empty?
@@ -33,6 +33,12 @@ class EmailMxValidator < ActiveModel::Validator
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 = []
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index cded4c99bd..1dae435360 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -206,7 +206,7 @@ RSpec.describe User, type: :model do
describe 'whitelist' do
around(:each) do |example|
- old_whitelist = Rails.configuration.x.email_whitelist
+ old_whitelist = Rails.configuration.x.email_domains_whitelist
Rails.configuration.x.email_domains_whitelist = 'mastodon.space'
diff --git a/spec/validators/email_mx_validator_spec.rb b/spec/validators/email_mx_validator_spec.rb
index 48e17a4f10..550e91996b 100644
--- a/spec/validators/email_mx_validator_spec.rb
+++ b/spec/validators/email_mx_validator_spec.rb
@@ -6,6 +6,24 @@ describe EmailMxValidator do
describe '#validate' do
let(:user) { double(email: 'foo@example.com', errors: double(add: nil)) }
+ it 'does not add errors if there are no DNS records for an e-mail domain that is explicitly allowed' do
+ old_whitelist = Rails.configuration.x.email_domains_whitelist
+ Rails.configuration.x.email_domains_whitelist = 'example.com'
+
+ 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([])
+ 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).to_not have_received(:add)
+
+ Rails.configuration.x.email_domains_whitelist = old_whitelist
+ end
+
it 'adds an error if there are no DNS records for the e-mail domain' do
resolver = double