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