Spencer McIntyre
fcd84a41aa
Move support for static entries out of the cache so it can be controlled like the other resolvers.
78 lines
2.5 KiB
Ruby
78 lines
2.5 KiB
Ruby
# -*- coding: binary -*-
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require 'net/dns/resolver'
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module Rex
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module Proto
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module DNS
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##
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# Provides Rex::Sockets compatible version of Net::DNS::Resolver
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# Modified to work with Dnsruby::Messages, their resolvers are too heavy
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##
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class CachedResolver < Resolver
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include Rex::Proto::DNS::Constants
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attr_accessor :cache
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#
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# Initialize resolver with cache
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#
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# @param config [Hash] Resolver config
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#
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# @return [nil]
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def initialize(config = {})
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dns_cache_no_start = config.delete(:dns_cache_no_start)
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super(config)
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self.cache = Rex::Proto::DNS::Cache.new
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self.cache.start unless dns_cache_no_start
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return
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end
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#
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# Attempt to find answers to query in DNS cache; failing that,
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# send remainder of DNS queries over appropriate transport and
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# cache answers before returning to caller.
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#
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# @param argument [Object] An object holding the DNS message to be processed.
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# @param type [Fixnum] Type of record to look up
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# @param cls [Fixnum] Class of question to look up
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#
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# @return [Dnsruby::Message, nil] DNS response on success, nil on failure.
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def send(argument, type = Dnsruby::Types::A, cls = Dnsruby::Classes::IN)
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case argument
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when Dnsruby::Message
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req = argument
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when Net::DNS::Packet, Resolv::DNS::Message
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req = Rex::Proto::DNS::Packet.encode_drb(argument)
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else
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net_packet = make_query_packet(argument,type,cls)
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# This returns a Net::DNS::Packet. Convert to Dnsruby::Message for consistency
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req = Rex::Proto::DNS::Packet.encode_drb(net_packet)
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end
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resolve = req.dup
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# Find cached items, remove request from resolved packet
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req.question.each do |ques|
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cached = self.cache.find(ques.qname, ques.qtype.to_s)
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next if cached.empty?
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req.instance_variable_set(:@answer, (req.answer + cached).uniq)
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resolve.question.delete(ques)
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end
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# Resolve remaining requests, cache responses
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if resolve.question.count > 0
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resolved = super(resolve, type)
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req.instance_variable_set(:@answer, (req.answer + resolved.answer).uniq)
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resolved.answer.each do |ans|
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self.cache.cache_record(ans)
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end
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end
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# Finalize answers in response
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# Check for empty response prior to sending
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req.header.rcode = Dnsruby::RCode::NOERROR if req.answer.size < 1
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req.header.qr = true # Set response bit
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return req
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end
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end
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end
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end
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end
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