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#--
#Copyright 2007 Nominet UK
#
#Licensed under the Apache License, Version 2.0 (the "License");
#you may not use this file except in compliance with the License.
#You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
#Unless required by applicable law or agreed to in writing, software
#distributed under the License is distributed on an "AS IS" BASIS,
#WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#See the License for the specific language governing permissions and
#limitations under the License.
#++
require 'base64'
begin
require 'Digest/sha2'
rescue LoadError
require 'digest/sha2'
end
module Dnsruby
class RR
#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].
class DS < RR
class DigestTypes < CodeMapper
update()
add_pair("SHA-1", 1)
add_pair("SHA-2", 2 )
end
ClassValue = nil #:nodoc: all
TypeValue = Types::DS #:nodoc: all
#The RDATA for a DS RR consists of a 2 octet Key Tag field, a 1 octet
#Algorithm field, a 1 octet Digest Type field, and a Digest field.
#
# 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
#+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#| Key Tag | Algorithm | Digest Type |
#+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#/ /
#/ Digest /
#/ /
#+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
#The Key Tag field lists the key tag of the DNSKEY RR referred to by
#the DS record, in network byte order.
attr_accessor :key_tag
#The algorithm used for this key
#See Dnsruby::Algorithms for permitted values
attr_reader :algorithm
#The DS RR refers to a DNSKEY RR by including a digest of that DNSKEY
#RR. The Digest Type field identifies the algorithm used to construct
#the digest.
attr_reader :digest_type
#The DS record refers to a DNSKEY RR by including a digest of that
#DNSKEY RR.
attr_accessor :digest
attr_accessor :digestbin
def digest_type=(d)
dig = DS.get_digest_type(d)
@digest_type = dig
end
def DS.get_digest_type(d)
if (d.instance_of?String)
if (d.length == 1)
d = d.to_i
end
end
begin
digest = DigestTypes.new(d)
return digest
rescue ArgumentError => e
raise DecodeError.new(e)
end
end
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
# Return the digest of the specified DNSKEY RR
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
# Check if the key's digest is the same as that stored in the DS record
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
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
def from_data(data) #:nodoc: all
key_tag, algorithm, digest_type, digest = data
self.key_tag=(key_tag)
self.algorithm=(algorithm)
self.digest_type=(digest_type)
self.digestbin=(digest)
self.digest=@digestbin.unpack("H*")[0]
end
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
def rdata_to_string #:nodoc: all
if (@key_tag != nil)
# return "#{@key_tag.to_i} #{@algorithm.string} #{@digest_type} ( #{Base64.encode64(@digest)} )"
# return "#{@key_tag.to_i} #{@algorithm.string} #{@digest_type.code} ( #{[@digest].pack("m*").gsub("\n", "")} )"
return "#{@key_tag.to_i} #{@algorithm.string} #{@digest_type.code} ( #{@digest.upcase} )"
else
return ""
end
end
def encode_rdata(msg, canonical=false) #:nodoc: all
msg.put_pack("ncc", @key_tag, @algorithm.code, @digest_type.code)
msg.put_bytes(@digestbin)
end
def self.decode_rdata(msg) #:nodoc: all
key_tag, algorithm, digest_type = msg.get_unpack("ncc")
digest = msg.get_bytes
return self.new(
[key_tag, algorithm, digest_type, digest])
end
end
end
end
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