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Bug fix for use-after-close connection in AXFR #523

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merged 2 commits into from
Feb 26, 2025
Merged

Bug fix for use-after-close connection in AXFR #523

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934e44a
Fix for use-after-close connection in AXFR
phillip-stephens Feb 25, 2025
d94ce0e
Use a new TransportFactory to make transport both mockable and a new …
phillip-stephens Feb 26, 2025
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1 change: 1 addition & 0 deletions go.mod
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ require (
github.com/prometheus/common v0.62.0 // indirect
github.com/prometheus/procfs v0.15.1 // indirect
github.com/rivo/uniseg v0.4.7 // indirect
github.com/stretchr/objx v0.5.2 // indirect
github.com/weppos/publicsuffix-go v0.40.3-0.20250127173806-e489a31678ca // indirect
github.com/zmap/rc2 v0.0.0-20190804163417-abaa70531248 // indirect
golang.org/x/crypto v0.33.0 // indirect
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1 change: 1 addition & 0 deletions go.sum
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Expand Up @@ -253,6 +253,7 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
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33 changes: 24 additions & 9 deletions src/modules/axfr/axfr.go
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Expand Up @@ -35,7 +35,23 @@ type AxfrLookupModule struct {
NSModule nslookup.NSLookupModule
BlacklistPath string `long:"blacklist-file" description:"path to blacklist file" default:""`
Blacklist *safeblacklist.SafeBlacklist
dns.Transfer
TransferFact TransferFactory
}

// TransferInterface used to enable mocking for dns.In
type TransferInterface interface {
In(m *dns.Msg, address string) (chan *dns.Envelope, error)
}

// TransferFactory each AXFR module isn't thread-safe, so we need to create a new Transfer object for each AXFR lookup
type TransferFactory interface {
NewTransfer() TransferInterface
}

type RealTransferFactory struct{}

func (f *RealTransferFactory) NewTransfer() TransferInterface {
return &dns.Transfer{}
}

type AXFRServerResult struct {
Expand All @@ -58,11 +74,7 @@ func dotName(name string) string {
return strings.Join([]string{name, "."}, "")
}

type TransferClient struct {
dns.Transfer
}

func (axfrMod *AxfrLookupModule) doAXFR(name string, server *zdns.NameServer) AXFRServerResult {
func (axfrMod *AxfrLookupModule) doAXFR(transfer TransferInterface, name string, server *zdns.NameServer) AXFRServerResult {
var retv AXFRServerResult
retv.Server = server.IP.String()
// check if the server address is blacklisted and if so, exclude
Expand All @@ -79,7 +91,7 @@ func (axfrMod *AxfrLookupModule) doAXFR(name string, server *zdns.NameServer) AX
}
m := new(dns.Msg)
m.SetAxfr(dotName(name))
if a, err := axfrMod.In(m, net.JoinHostPort(server.IP.String(), "53")); err != nil {
if a, err := transfer.In(m, net.JoinHostPort(server.IP.String(), "53")); err != nil {
retv.Status = zdns.StatusError
retv.Error = err.Error()
return retv
Expand All @@ -103,6 +115,8 @@ func (axfrMod *AxfrLookupModule) doAXFR(name string, server *zdns.NameServer) AX

func (axfrMod *AxfrLookupModule) Lookup(resolver *zdns.Resolver, name string, nameServer *zdns.NameServer) (interface{}, zdns.Trace, zdns.Status, error) {
var retv AXFRResult
// create a new AXFR transfer object
transfer := axfrMod.TransferFact.NewTransfer()
if nameServer == nil {
parsedNS, trace, status, err := axfrMod.NSModule.Lookup(resolver, name, nameServer)
if status != zdns.StatusNoError {
Expand All @@ -115,11 +129,11 @@ func (axfrMod *AxfrLookupModule) Lookup(resolver *zdns.Resolver, name string, na
for _, server := range castedNS.Servers {
if len(server.IPv4Addresses) > 0 {
ns := &zdns.NameServer{IP: net.ParseIP(server.IPv4Addresses[0])}
retv.Servers = append(retv.Servers, axfrMod.doAXFR(name, ns))
retv.Servers = append(retv.Servers, axfrMod.doAXFR(transfer, name, ns))
}
}
} else {
retv.Servers = append(retv.Servers, axfrMod.doAXFR(name, nameServer))
retv.Servers = append(retv.Servers, axfrMod.doAXFR(transfer, name, nameServer))
}
return retv, nil, zdns.StatusNoError, nil
}
Expand Down Expand Up @@ -168,5 +182,6 @@ func (axfrMod *AxfrLookupModule) CLIInit(gc *cli.CLIConf, rc *zdns.ResolverConfi
if err = axfrMod.BasicLookupModule.CLIInit(gc, rc); err != nil {
return errors.Wrap(err, "failed to initialize basic lookup module")
}
axfrMod.TransferFact = &RealTransferFactory{} // Default factory
return nil
}
16 changes: 15 additions & 1 deletion src/modules/axfr/axfr_test.go
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Expand Up @@ -20,6 +20,7 @@ import (
"testing"

"github.com/miekg/dns"
"github.com/stretchr/testify/mock"
"gotest.tools/v3/assert"

"github.com/zmap/zdns/src/cli"
Expand All @@ -45,7 +46,19 @@ func (err enError) Error() string {
return envelopeError
}

func (axfrMod *AxfrLookupModule) In(m *dns.Msg, server string) (chan *dns.Envelope, error) {
type MockTransfer struct {
mock.Mock
}

type MockTransferFactory struct {
Mock *MockTransfer
}

func (f *MockTransferFactory) NewTransfer() TransferInterface {
return f.Mock
}

func (mock *MockTransfer) In(m *dns.Msg, server string) (chan *dns.Envelope, error) {
var eError error = nil
if envelopeError != "" {
eError = enError{}
Expand Down Expand Up @@ -102,6 +115,7 @@ func InitTest() (*AxfrLookupModule, *zdns.Resolver) {
if err != nil {
panic("failed to initialize axfr test lookup with error: " + err.Error())
}
axfrMod.TransferFact = &MockTransferFactory{Mock: new(MockTransfer)} // configure the mock transfer factory
resolver, err := zdns.InitResolver(rc)
if err != nil {
panic("failed to initialize resolver: " + err.Error())
Expand Down
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