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13e66918e3
* When returning NS for delegation point, we sign any DS Record or if not found we generate a NSEC proving absence of DS. This follow behaviour describe in rfc4035 (Section 3.1.4) * DS request at apex behave as before. * Fix edge case of requesting NSEC which prove that NSEC does not exist. Signed-off-by: Jeremiejig <me@jeremiejig.fr>
80 lines
3.0 KiB
Go
80 lines
3.0 KiB
Go
package dnssec
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import (
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"strings"
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"github.com/coredns/coredns/plugin/pkg/response"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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// nsec returns an NSEC useful for NXDOMAIN responses.
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// See https://tools.ietf.org/html/draft-valsorda-dnsop-black-lies-00
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// For example, a request for the non-existing name a.example.com would
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// cause the following NSEC record to be generated:
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//
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// a.example.com. 3600 IN NSEC \000.a.example.com. ( RRSIG NSEC ... )
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//
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// This inturn makes every NXDOMAIN answer a NODATA one, don't forget to flip
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// the header rcode to NOERROR.
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func (d Dnssec) nsec(state request.Request, mt response.Type, ttl, incep, expir uint32, server string) ([]dns.RR, error) {
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nsec := &dns.NSEC{}
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nsec.Hdr = dns.RR_Header{Name: state.QName(), Ttl: ttl, Class: dns.ClassINET, Rrtype: dns.TypeNSEC}
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nsec.NextDomain = "\\000." + state.QName()
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if state.QName() == "." {
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nsec.NextDomain = "\\000." // If You want to play as root server
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}
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if state.Name() == state.Zone {
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nsec.TypeBitMap = filter18(state.QType(), apexBitmap, mt)
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} else if mt == response.Delegation || state.QType() == dns.TypeDS {
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nsec.TypeBitMap = delegationBitmap[:]
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if mt == response.Delegation {
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labels := dns.SplitDomainName(state.QName())
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labels[0] += "\\000"
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nsec.NextDomain = strings.Join(labels, ".") + "."
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}
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} else {
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nsec.TypeBitMap = filter14(state.QType(), zoneBitmap, mt)
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}
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sigs, err := d.sign([]dns.RR{nsec}, state.Zone, ttl, incep, expir, server)
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if err != nil {
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return nil, err
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}
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return append(sigs, nsec), nil
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}
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// The NSEC bit maps we return.
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var (
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delegationBitmap = [...]uint16{dns.TypeA, dns.TypeNS, dns.TypeHINFO, dns.TypeTXT, dns.TypeAAAA, dns.TypeLOC, dns.TypeSRV, dns.TypeCERT, dns.TypeSSHFP, dns.TypeRRSIG, dns.TypeNSEC, dns.TypeTLSA, dns.TypeHIP, dns.TypeOPENPGPKEY, dns.TypeSPF}
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zoneBitmap = [...]uint16{dns.TypeA, dns.TypeHINFO, dns.TypeTXT, dns.TypeAAAA, dns.TypeLOC, dns.TypeSRV, dns.TypeCERT, dns.TypeSSHFP, dns.TypeRRSIG, dns.TypeNSEC, dns.TypeTLSA, dns.TypeHIP, dns.TypeOPENPGPKEY, dns.TypeSPF}
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apexBitmap = [...]uint16{dns.TypeA, dns.TypeNS, dns.TypeSOA, dns.TypeHINFO, dns.TypeMX, dns.TypeTXT, dns.TypeAAAA, dns.TypeLOC, dns.TypeSRV, dns.TypeCERT, dns.TypeSSHFP, dns.TypeRRSIG, dns.TypeNSEC, dns.TypeDNSKEY, dns.TypeTLSA, dns.TypeHIP, dns.TypeOPENPGPKEY, dns.TypeSPF}
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)
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// filter14 filters out t from bitmap (if it exists). If mt is not an NODATA response, just return the entire bitmap.
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func filter14(t uint16, bitmap [14]uint16, mt response.Type) []uint16 {
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if mt != response.NoData && mt != response.NameError || t == dns.TypeNSEC {
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return zoneBitmap[:]
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}
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for i := range bitmap {
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if bitmap[i] == t {
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return append(bitmap[:i], bitmap[i+1:]...)
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}
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}
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return zoneBitmap[:] // make a slice
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}
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func filter18(t uint16, bitmap [18]uint16, mt response.Type) []uint16 {
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if mt != response.NoData && mt != response.NameError || t == dns.TypeNSEC {
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return apexBitmap[:]
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}
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for i := range bitmap {
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if bitmap[i] == t {
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return append(bitmap[:i], bitmap[i+1:]...)
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}
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}
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return apexBitmap[:] // make a slice
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}
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