126 lines
3.2 KiB
Go
126 lines
3.2 KiB
Go
// Copyright 2011 Miek Gieben. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package dns
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import (
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"crypto/sha1"
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"hash"
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"io"
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"strings"
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)
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const (
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_ = iota
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_NSEC3_NXDOMAIN
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_NSEC3_NODATA
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)
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type saltWireFmt struct {
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Salt string `dns:"size-hex"`
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}
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// HashName hashes a string (label) according to RFC 5155. It returns the hashed string.
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func HashName(label string, ha uint8, iter uint16, salt string) string {
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saltwire := new(saltWireFmt)
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saltwire.Salt = salt
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wire := make([]byte, DefaultMsgSize)
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n, err := PackStruct(saltwire, wire, 0)
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if err != nil {
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return ""
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}
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wire = wire[:n]
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name := make([]byte, 255)
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off, err := PackDomainName(strings.ToLower(label), name, 0, nil, false)
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if err != nil {
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return ""
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}
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name = name[:off]
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var s hash.Hash
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switch ha {
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case SHA1:
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s = sha1.New()
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default:
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return ""
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}
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// k = 0
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name = append(name, wire...)
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io.WriteString(s, string(name))
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nsec3 := s.Sum(nil)
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// k > 0
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for k := uint16(0); k < iter; k++ {
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s.Reset()
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nsec3 = append(nsec3, wire...)
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io.WriteString(s, string(nsec3))
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nsec3 = s.Sum(nil)
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}
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return unpackBase32(nsec3)
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}
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// Implement the HashNames method of Denialer
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func (rr *NSEC3) HashNames(domain string) {
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rr.Header().Name = strings.ToLower(HashName(rr.Header().Name, rr.Hash, rr.Iterations, rr.Salt)) + "." + domain
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rr.NextDomain = HashName(rr.NextDomain, rr.Hash, rr.Iterations, rr.Salt)
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}
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// Implement the Match method of Denialer
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func (rr *NSEC3) Match(domain string) bool {
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return strings.ToUpper(SplitLabels(rr.Header().Name)[0]) == strings.ToUpper(HashName(domain, rr.Hash, rr.Iterations, rr.Salt))
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}
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// Implement the Match method of Denialer
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func (rr *NSEC) Match(domain string) bool {
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return strings.ToUpper(rr.Header().Name) == strings.ToUpper(domain)
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}
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func (rr *NSEC3) MatchType(rrtype uint16) bool {
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for _, t := range rr.TypeBitMap {
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if t == rrtype {
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return true
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}
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if t > rrtype {
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return false
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}
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}
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return false
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}
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func (rr *NSEC) MatchType(rrtype uint16) bool {
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for _, t := range rr.TypeBitMap {
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if t == rrtype {
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return true
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}
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if t > rrtype {
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return false
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}
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}
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return false
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}
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// Cover checks if domain is covered by the NSEC3 record. Domain must be given in plain text (i.e. not hashed)
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// TODO(mg): this doesn't loop around
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// TODO(mg): make a CoverHashed variant?
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func (rr *NSEC3) Cover(domain string) bool {
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hashdom := strings.ToUpper(HashName(domain, rr.Hash, rr.Iterations, rr.Salt))
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nextdom := strings.ToUpper(rr.NextDomain)
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owner := strings.ToUpper(SplitLabels(rr.Header().Name)[0]) // The hashed part
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apex := strings.ToUpper(HashName(strings.Join(SplitLabels(rr.Header().Name)[1:], "."), rr.Hash, rr.Iterations, rr.Salt)) + "." // The name of the zone
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// if nextdomain equals the apex, it is considered The End. So in that case hashdom is always less then nextdomain
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if hashdom > owner && nextdom == apex {
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return true
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}
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if hashdom > owner && hashdom <= nextdom {
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return true
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}
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return false
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}
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// Cover checks if domain is covered by the NSEC record. Domain must be given in plain text.
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func (rr *NSEC) Cover(domain string) bool {
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return false
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}
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