* 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
		
			
				
	
	
		
			63 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
			
		
		
	
	
			63 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
| # frozen_string_literal: true
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| 
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| require 'resolv'
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| 
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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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| 
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|     domain = get_domain(user.email)
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| 
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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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| 
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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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| 
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|   private
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| 
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|   def get_domain(value)
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|     _, domain = value.split('@', 2)
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| 
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|     return nil if domain.nil?
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| 
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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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| 
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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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| 
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|     Rails.configuration.x.email_domains_whitelist.include?(domain)
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|   end
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| 
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|   def resolve_mx(domain)
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|     hostnames = []
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|     ips       = []
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| 
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|     Resolv::DNS.open do |dns|
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|       dns.timeouts = 5
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| 
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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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| 
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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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| 
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|     [ips, hostnames]
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|   end
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| 
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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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