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

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* 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

25
plugin/file/lookup.go
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@@ -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