RFC4034, section 4 The DS Resource Record refers to a DNSKEY RR and is used in the DNS DNSKEY authentication process. A DS RR refers to a DNSKEY RR by storing the key tag, algorithm number, and a digest of the DNSKEY RR. Note that while the digest should be sufficient to identify the public key, storing the key tag and key algorithm helps make the identification process more efficient. By authenticating the DS record, a resolver can authenticate the DNSKEY RR to which the DS record points. The key authentication process is described in [RFC4035].
# File lib/Dnsruby/resource/DS.rb, line 149 def DS.from_key(key, digest_type) ## The key must not be a NULL key. # if ((key.flags & 0xc000 ) == 0xc000 ) # puts "\nCreating a DS record for a NULL key is illegal" # return # end # # # Bit 0 must not be set. # if (key.flags & 0x8000) # puts "\nCreating a DS record for a key with flag bit 0 set " + # "to 0 is illegal" # return # end # # Bit 6 must be set to 0 bit 7 must be set to 1 if (( key.flags & 0x300) != 0x100) puts "\nCreating a DS record for a key with flags 6 and 7 not set "+ "0 and 1 respectively is illegal" return end # # # if (key.protocol != 3 ) # puts "\nCreating a DS record for a non DNSSEC (protocol=3) " + # "key is illegal" # return # end # digest_type = get_digest_type(digest_type) # Create a new DS record from the specified key ds = RR.create(:name => key.name, :type => "DS", :ttl => key.ttl, :key_tag => key.key_tag, :digest_type => digest_type, :algorithm => key.algorithm) ds.digestbin = ds.digest_key(key, digest_type) ds.digest = ds.digestbin.unpack("H*")[0] return ds end
# File lib/Dnsruby/resource/DS.rb, line 93 def algorithm=(a) if (a.instance_of?String) if (a.length < 3) a = a.to_i end end begin alg = Algorithms.new(a) @algorithm = alg rescue ArgumentError => e raise DecodeError.new(e) end end
Check if the key’s digest is the same as that stored in the DS record
# File lib/Dnsruby/resource/DS.rb, line 133 def check_key(key) if ((key.key_tag == @key_tag) && (key.algorithm == @algorithm)) digestbin = digest_key(key) if (@digestbin == digestbin) if (!key.zone_key?) else return true end else end end return false end
Return the digest of the specified DNSKEY RR
# File lib/Dnsruby/resource/DS.rb, line 108 def digest_key(*args) # key, digest_type) digest_type = @digest_type key = args[0] if (args.length == 2) digest_type = args[1] end data = MessageEncoder.new {|msg| msg.put_name(key.name, true) key.encode_rdata(msg, true) }.to_s if (digest_type.code == 1) digestbin = OpenSSL::Digest::SHA1.digest(data) return digestbin elsif (digest_type.code == 2) digestbin = Digest::SHA256.digest(data) return digestbin end end
# File lib/Dnsruby/resource/DS.rb, line 74 def digest_type=(d) dig = DS.get_digest_type(d) @digest_type = dig end
# File lib/Dnsruby/resource/DS.rb, line 197 def from_string(input) if (input.length > 0) data = input.split(" ") self.key_tag=(data[0].to_i) self.algorithm=(data[1]) self.digest_type=(data[2]) buf = "" index = 3 end_index = data.length - 1 if (data[index]=="(") end_index = data.length - 2 index = 4 end (index..end_index).each {|i| if (comment_index = data[i].index(";")) buf += data[i].slice(0, comment_index) # @TODO@ We lose the comments here - we should really keep them for when we write back to string format? break else buf += data[i] end } # self.digest=Base64.decode64(buf) buf.gsub!(/\n/, "") buf.gsub!(/ /, "") # self.digest=buf.unpack("m*")[0] self.digest=buf self.digestbin = [buf].pack("H*") end end
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