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middleware/file: Add CNAME chain support (#400)

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Up till now we would only chase 1 CNAME. Spec requires we will chase
all. This PR add support for this.  Up to 8 CNAMEs are chased (this
could be longer, by just checking for cycles, but 8 seems enough for
now).

Also add RRSIG of the first CNAME for DNSSEC.
This commit is contained in:
Miek Gieben 2016-11-09 10:02:26 +00:00 • committed by GitHub
parent 6abbe231e5
commit 4ef53081c5
4 changed files with 157 additions and 16 deletions
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98
middleware/file/cname_test.go Normal file
View file

@ -0,0 +1,98 @@
package file
import (
"sort"
"strings"
"testing"
"github.com/miekg/coredns/middleware/pkg/dnsrecorder"
"github.com/miekg/coredns/middleware/test"
"github.com/miekg/dns"
"golang.org/x/net/context"
)
func TestLookupCNAMEChain(t *testing.T) {
name := "example.org."
zone, err := Parse(strings.NewReader(dbExampleCNAME), name, "stdin")
if err != nil {
t.Fatalf("Expected no error when reading zone, got %q", err)
}
fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{name: zone}, Names: []string{name}}}
ctx := context.TODO()
for _, tc := range cnameTestCases {
m := tc.Msg()
rec := dnsrecorder.New(&test.ResponseWriter{})
_, err := fm.ServeDNS(ctx, rec, m)
if err != nil {
t.Errorf("Expected no error, got %v\n", err)
return
}
resp := rec.Msg
sort.Sort(test.RRSet(resp.Answer))
sort.Sort(test.RRSet(resp.Ns))
sort.Sort(test.RRSet(resp.Extra))
if !test.Header(t, tc, resp) {
t.Logf("%v\n", resp)
continue
}
if !test.Section(t, tc, test.Answer, resp.Answer) {
t.Logf("%v\n", resp)
}
if !test.Section(t, tc, test.Ns, resp.Ns) {
t.Logf("%v\n", resp)
}
if !test.Section(t, tc, test.Extra, resp.Extra) {
t.Logf("%v\n", resp)
}
}
}
var cnameTestCases = []test.Case{
{
Qname: "a.example.org.", Qtype: dns.TypeA,
Answer: []dns.RR{
test.A("a.example.org. 1800 IN A 127.0.0.1"),
},
},
{
Qname: "www3.example.org.", Qtype: dns.TypeCNAME,
Answer: []dns.RR{
test.CNAME("www3.example.org. 1800 IN CNAME www2.example.org."),
},
},
{
Qname: "www3.example.org.", Qtype: dns.TypeA,
Answer: []dns.RR{
test.A("a.example.org. 1800 IN A 127.0.0.1"),
test.CNAME("www.example.org. 1800 IN CNAME a.example.org."),
test.CNAME("www1.example.org. 1800 IN CNAME www.example.org."),
test.CNAME("www2.example.org. 1800 IN CNAME www1.example.org."),
test.CNAME("www3.example.org. 1800 IN CNAME www2.example.org."),
},
},
}
const dbExampleCNAME = `
$TTL 30M
$ORIGIN example.org.
@ IN SOA linode.atoom.net. miek.miek.nl. (
1282630057 ; Serial
4H ; Refresh
1H ; Retry
7D ; Expire
4H ) ; Negative Cache TTL
a IN A 127.0.0.1
www3 IN CNAME www2
www2 IN CNAME www1
www1 IN CNAME www
www IN CNAME a
dangling IN CNAME foo`

5
middleware/file/dnssec_test.go
View file

@ -58,6 +58,7 @@ var dnssecTestCases = []test.Case{
test.A("a.miek.nl. 1800 IN A 139.162.196.78"),
test.RRSIG("a.miek.nl. 1800 IN RRSIG A 8 3 1800 20160426031301 20160327031301 12051 miek.nl. lxLotCjWZ3kihTxk="),
test.CNAME("www.miek.nl. 1800 IN CNAME a.miek.nl."),
test.RRSIG("www.miek.nl. 1800 RRSIG CNAME 8 3 1800 20160426031301 20160327031301 12051 miek.nl. NVZmMJaypS+wDL2Lar4Zw1zF"),
},
Extra: []dns.RR{
@ -118,7 +119,7 @@ var dnssecTestCases = []test.Case{
func TestLookupDNSSEC(t *testing.T) {
zone, err := Parse(strings.NewReader(dbMiekNLSigned), testzone, "stdin")
if err != nil {
t.Fatalf("expect no error when reading zone, got %q", err)
t.Fatalf("Expected no error when reading zone, got %q", err)
}
fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{testzone: zone}, Names: []string{testzone}}}
@ -130,7 +131,7 @@ func TestLookupDNSSEC(t *testing.T) {
rec := dnsrecorder.New(&test.ResponseWriter{})
_, err := fm.ServeDNS(ctx, rec, m)
if err != nil {
t.Errorf("expected no error, got %v\n", err)
t.Errorf("Expected no error, got %v\n", err)
return
}

4
middleware/file/ds_test.go
View file

@ -54,7 +54,7 @@ var dsTestCases = []test.Case{
func TestLookupDS(t *testing.T) {
zone, err := Parse(strings.NewReader(dbMiekNLDelegation), testzone, "stdin")
if err != nil {
t.Fatalf("expect no error when reading zone, got %q", err)
t.Fatalf("Expected no error when reading zone, got %q", err)
}
fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{testzone: zone}, Names: []string{testzone}}}
@ -66,7 +66,7 @@ func TestLookupDS(t *testing.T) {
rec := dnsrecorder.New(&test.ResponseWriter{})
_, err := fm.ServeDNS(ctx, rec, m)
if err != nil {
t.Errorf("expected no error, got %v\n", err)
t.Errorf("Expected no error, got %v\n", err)
return
}

66
middleware/file/lookup.go
View file

@ -118,8 +118,9 @@ func (z *Zone) Lookup(qname string, qtype uint16, do bool) ([]dns.RR, []dns.RR,
// Found entire name.
if found && shot {
if rrs := elem.Types(dns.TypeCNAME, qname); len(rrs) > 0 {
return z.searchCNAME(rrs, qtype, do)
// DNAME...
if rrs := elem.Types(dns.TypeCNAME); len(rrs) > 0 && qtype != dns.TypeCNAME {
return z.searchCNAME(elem, rrs, qtype, do)
}
rrs := elem.Types(qtype, qname)
@ -151,7 +152,7 @@ func (z *Zone) Lookup(qname string, qtype uint16, do bool) ([]dns.RR, []dns.RR,
auth := []dns.RR{}
if rrs := wildElem.Types(dns.TypeCNAME, qname); len(rrs) > 0 {
return z.searchCNAME(rrs, qtype, do)
return z.searchCNAME(wildElem, rrs, qtype, do)
}
rrs := wildElem.Types(qtype, qname)
@ -250,22 +251,61 @@ func (z *Zone) ns(do bool) []dns.RR {
return z.Apex.NS
}
func (z *Zone) searchCNAME(rrs []dns.RR, qtype uint16, do bool) ([]dns.RR, []dns.RR, []dns.RR, Result) {
elem, _ := z.Tree.Search(rrs[0].(*dns.CNAME).Target)
func (z *Zone) searchCNAME(elem *tree.Elem, rrs []dns.RR, qtype uint16, do bool) ([]dns.RR, []dns.RR, []dns.RR, Result) {
if do {
sigs := elem.Types(dns.TypeRRSIG)
sigs = signatureForSubType(sigs, dns.TypeCNAME)
if len(sigs) > 0 {
rrs = append(rrs, sigs...)
}
}
elem, _ = z.Tree.Search(rrs[0].(*dns.CNAME).Target)
if elem == nil {
return rrs, nil, nil, Success
}
// RECURSIVE SEARCH, up to 8 deep. Also: tests.
i := 0
Redo:
cname := elem.Types(dns.TypeCNAME)
if len(cname) > 0 {
rrs = append(rrs, cname...)
if do {
sigs := elem.Types(dns.TypeRRSIG)
sigs = signatureForSubType(sigs, dns.TypeCNAME)
if len(sigs) > 0 {
rrs = append(rrs, sigs...)
}
}
elem, _ = z.Tree.Search(cname[0].(*dns.CNAME).Target)
if elem == nil {
return rrs, nil, nil, Success
}
i++
if i > maxChain {
return rrs, nil, nil, Success
}
goto Redo
}
targets := cnameForType(elem.All(), qtype)
if do {
sigs := elem.Types(dns.TypeRRSIG)
sigs = signatureForSubType(sigs, qtype)
if len(sigs) > 0 {
targets = append(targets, sigs...)
if len(targets) > 0 {
rrs = append(rrs, targets...)
if do {
sigs := elem.Types(dns.TypeRRSIG)
sigs = signatureForSubType(sigs, qtype)
if len(sigs) > 0 {
rrs = append(rrs, sigs...)
}
}
}
return append(rrs, targets...), nil, nil, Success
return rrs, nil, nil, Success
}
func cnameForType(targets []dns.RR, origQtype uint16) []dns.RR {
@ -317,3 +357,5 @@ func (z *Zone) searchGlue(name string) []dns.RR {
}
return glue
}
const maxChain = 8