Mirrors/coredns
1
0
Fork 0
mirror of https://github.com/coredns/coredns.git synced 2025-10-27 08:14:18 -04:00
Code Issues Packages Projects Releases Wiki Activity

plugin/file: fix local CNAME lookup (#1866)

Browse Source 
* plugin/file: fix local CNAME lookup

Issue #1864 explains it will, when we serve the child zone as well we
should just recursive into ourself (upstream self). Thus relax the
IsSubDomain check in file/lookup.go and just query (even if the query
will hit a remote server).

I've looped over all other plugins that do something similar (CNAME
resolving) and they didn't do the IsSubDomain check; therefor I've
removed it from *file* as well.

Added test in file_upstream_test that shows this failed before but now
results in a reply.

Fixes #1864

* self does not need to be exported

* Fix test

We don't know if we had a valid reply. Check this.
This commit is contained in:
Miek Gieben
2018-06-12 14:54:37 +01:00
committed by GitHub
parent 6e466d5092
commit 26c41a0c17
5 changed files with 83 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
plugin/backend_lookup.go
View File

@@ -122,12 +122,9 @@ func AAAA(b ServiceBackend, zone string, state request.Request, previousRecords
}
continue
}
// This means we can not complete the CNAME, try to look else where.
target := newRecord.Target
if dns.IsSubDomain(zone, target) {
// We should already have found it
continue
}
m1, e1 := b.Lookup(state, target, state.QType())
if e1 != nil {
continue

25
plugin/file/lookup.go
View File

@@ -106,7 +106,7 @@ func (z *Zone) Lookup(state request.Request, qname string) ([]dns.RR, []dns.RR,
// Only one DNAME is allowed per name. We just pick the first one to synthesize from.
dname := dnamerrs[0]
if cname := synthesizeCNAME(state.Name(), dname.(*dns.DNAME)); cname != nil {
answer, ns, extra, rcode := z.searchCNAME(state, elem, []dns.RR{cname})
answer, ns, extra, rcode := z.additionalProcessing(state, elem, []dns.RR{cname})
if do {
sigs := elem.Types(dns.TypeRRSIG)
@@ -157,7 +157,7 @@ func (z *Zone) Lookup(state request.Request, qname string) ([]dns.RR, []dns.RR,
if found && shot {
if rrs := elem.Types(dns.TypeCNAME); len(rrs) > 0 && qtype != dns.TypeCNAME {
return z.searchCNAME(state, elem, rrs)
return z.additionalProcessing(state, elem, rrs)
}
rrs := elem.Types(qtype, qname)
@@ -193,7 +193,7 @@ func (z *Zone) Lookup(state request.Request, qname string) ([]dns.RR, []dns.RR,
auth := z.ns(do)
if rrs := wildElem.Types(dns.TypeCNAME, qname); len(rrs) > 0 {
return z.searchCNAME(state, wildElem, rrs)
return z.additionalProcessing(state, wildElem, rrs)
}
rrs := wildElem.Types(qtype, qname)
@@ -295,8 +295,8 @@ func (z *Zone) ns(do bool) []dns.RR {
return z.Apex.NS
}
// TODO(miek): should be better named, like aditionalProcessing?
func (z *Zone) searchCNAME(state request.Request, elem *tree.Elem, rrs []dns.RR) ([]dns.RR, []dns.RR, []dns.RR, Result) {
// aditionalProcessing adds signatures and tries to resolve CNAMEs that point to external names.
func (z *Zone) additionalProcessing(state request.Request, elem *tree.Elem, rrs []dns.RR) ([]dns.RR, []dns.RR, []dns.RR, Result) {
qtype := state.QType()
do := state.Do()
@@ -312,9 +312,7 @@ func (z *Zone) searchCNAME(state request.Request, elem *tree.Elem, rrs []dns.RR)
targetName := rrs[0].(*dns.CNAME).Target
elem, _ = z.Tree.Search(targetName)
if elem == nil {
if !dns.IsSubDomain(z.origin, targetName) {
rrs = append(rrs, z.externalLookup(state, targetName, qtype)...)
}
rrs = append(rrs, z.externalLookup(state, targetName, qtype)...)
return rrs, z.ns(do), nil, Success
}
@@ -335,11 +333,7 @@ Redo:
targetName := cname[0].(*dns.CNAME).Target
elem, _ = z.Tree.Search(targetName)
if elem == nil {
if !dns.IsSubDomain(z.origin, targetName) {
if !dns.IsSubDomain(z.origin, targetName) {
rrs = append(rrs, z.externalLookup(state, targetName, qtype)...)
}
}
rrs = append(rrs, z.externalLookup(state, targetName, qtype)...)
return rrs, z.ns(do), nil, Success
}
@@ -380,7 +374,10 @@ func cnameForType(targets []dns.RR, origQtype uint16) []dns.RR {
func (z *Zone) externalLookup(state request.Request, target string, qtype uint16) []dns.RR {
m, e := z.Upstream.Lookup(state, target, qtype)
if e != nil {
// TODO(miek): debugMsg for this as well? Log?
// TODO(miek): Log, or return error here?
return nil
}
if m == nil {
return nil
}
return m.Answer

17
plugin/pkg/upstream/upstream.go
View File

@@ -18,7 +18,8 @@ type Upstream struct {
Forward *proxy.Proxy
}
// NewUpstream creates a new Upstream for given destination(s)
// NewUpstream creates a new Upstream for given destination(s). If dests is empty
// it default to upstreaming to Self.
func NewUpstream(dests []string) (Upstream, error) {
u := Upstream{}
if len(dests) == 0 {
@@ -35,21 +36,23 @@ func NewUpstream(dests []string) (Upstream, error) {
return u, nil
}
// Lookup routes lookups to Self or Forward
// Lookup routes lookups to our selves or forward to a remote.
func (u Upstream) Lookup(state request.Request, name string, typ uint16) (*dns.Msg, error) {
if u.self {
// lookup via self
req := new(dns.Msg)
req.SetQuestion(name, typ)
state.SizeAndDo(req)
nw := nonwriter.New(state.W)
state2 := request.Request{W: nw, Req: req}
server := state.Context.Value(dnsserver.Key{}).(*dnsserver.Server)
server.ServeDNS(state.Context, state2.W, req)
server.ServeDNS(state.Context, nw, req)
return nw.Msg, nil
}
if u.Forward != nil {
return u.Forward.Lookup(state, name, typ)
}
return &dns.Msg{}, nil
return nil, nil
}

2
plugin/secondary/setup.go
View File

@@ -5,8 +5,8 @@ import (
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/file"
"github.com/coredns/coredns/plugin/pkg/parse"
"github.com/coredns/coredns/plugin/pkg/upstream"
"github.com/mholt/caddy"
)

62
test/file_upstream_test.go
View File

@@ -6,8 +6,6 @@ import (
"github.com/miekg/dns"
)
// TODO(miek): this test needs to be fleshed out.
func TestFileUpstream(t *testing.T) {
name, rm, err := TempFile(".", `$ORIGIN example.org.
@ 3600 IN SOA sns.dns.icann.org. noc.dns.icann.org. (
@@ -59,3 +57,63 @@ www 3600 IN CNAME www.example.net.
t.Errorf("Failed to get address for CNAME, expected 10.0.0.1 got %s", x)
}
}
// TestFileUpstreamAdditional runs two CoreDNS servers that serve example.org and foo.example.org.
// example.org contains a cname to foo.example.org; this should be resolved via upstream.Self.
func TestFileUpstreamAdditional(t *testing.T) {
name, rm, err := TempFile(".", `$ORIGIN example.org.
@ 3600 IN SOA sns.dns.icann.org. noc.dns.icann.org. 2017042745 7200 3600 1209600 3600
3600 IN NS b.iana-servers.net.
www 3600 IN CNAME www.foo
`)
if err != nil {
t.Fatalf("Failed to create zone: %s", err)
}
defer rm()
name2, rm2, err2 := TempFile(".", `$ORIGIN foo.example.org.
@ 3600 IN SOA sns.dns.icann.org. noc.dns.icann.org. 2017042745 7200 3600 1209600 3600
3600 IN NS b.iana-servers.net.
www 3600 IN A 127.0.0.53
`)
if err2 != nil {
t.Fatalf("Failed to create zone: %s", err2)
}
defer rm2()
corefile := `.:0 {
file ` + name + ` example.org {
upstream
}
file ` + name2 + ` foo.example.org {
upstream
}
}
`
i, udp, _, err := CoreDNSServerAndPorts(corefile)
if err != nil {
t.Fatalf("Could not get CoreDNS serving instance: %s", err)
}
defer i.Stop()
m := new(dns.Msg)
m.SetQuestion("www.example.org.", dns.TypeA)
r, err := dns.Exchange(m, udp)
if err != nil {
t.Fatalf("Could not exchange msg: %s", err)
}
if r.Rcode == dns.RcodeServerFailure {
t.Fatalf("Rcode should not be dns.RcodeServerFailure")
}
if x := len(r.Answer); x != 2 {
t.Errorf("Expected 2 RR in reply, got %d", x)
}
if x := r.Answer[1].(*dns.A).A.String(); x != "127.0.0.53" {
t.Errorf("Failed to get address for CNAME, expected 127.0.0.53, got %s", x)
}
}