t.Errorf("names = %q; want %q", names, want)
}
}
+
+func TestCVE202133195(t *testing.T) {
+ fake := fakeDNSServer{
+ rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+ r := dnsmessage.Message{
+ Header: dnsmessage.Header{
+ ID: q.Header.ID,
+ Response: true,
+ RCode: dnsmessage.RCodeSuccess,
+ RecursionAvailable: true,
+ },
+ Questions: q.Questions,
+ }
+ switch q.Questions[0].Type {
+ case dnsmessage.TypeCNAME:
+ r.Answers = []dnsmessage.Resource{}
+ case dnsmessage.TypeA: // CNAME lookup uses a A/AAAA as a proxy
+ r.Answers = append(r.Answers,
+ dnsmessage.Resource{
+ Header: dnsmessage.ResourceHeader{
+ Name: dnsmessage.MustNewName("<html>.golang.org."),
+ Type: dnsmessage.TypeA,
+ Class: dnsmessage.ClassINET,
+ Length: 4,
+ },
+ Body: &dnsmessage.AResource{
+ A: TestAddr,
+ },
+ },
+ )
+ case dnsmessage.TypeSRV:
+ n := q.Questions[0].Name
+ if n.String() == "_hdr._tcp.golang.org." {
+ n = dnsmessage.MustNewName("<html>.golang.org.")
+ }
+ r.Answers = append(r.Answers,
+ dnsmessage.Resource{
+ Header: dnsmessage.ResourceHeader{
+ Name: n,
+ Type: dnsmessage.TypeSRV,
+ Class: dnsmessage.ClassINET,
+ Length: 4,
+ },
+ Body: &dnsmessage.SRVResource{
+ Target: dnsmessage.MustNewName("<html>.golang.org."),
+ },
+ },
+ )
+ case dnsmessage.TypeMX:
+ r.Answers = append(r.Answers,
+ dnsmessage.Resource{
+ Header: dnsmessage.ResourceHeader{
+ Name: dnsmessage.MustNewName("<html>.golang.org."),
+ Type: dnsmessage.TypeMX,
+ Class: dnsmessage.ClassINET,
+ Length: 4,
+ },
+ Body: &dnsmessage.MXResource{
+ MX: dnsmessage.MustNewName("<html>.golang.org."),
+ },
+ },
+ )
+ case dnsmessage.TypeNS:
+ r.Answers = append(r.Answers,
+ dnsmessage.Resource{
+ Header: dnsmessage.ResourceHeader{
+ Name: dnsmessage.MustNewName("<html>.golang.org."),
+ Type: dnsmessage.TypeNS,
+ Class: dnsmessage.ClassINET,
+ Length: 4,
+ },
+ Body: &dnsmessage.NSResource{
+ NS: dnsmessage.MustNewName("<html>.golang.org."),
+ },
+ },
+ )
+ case dnsmessage.TypePTR:
+ r.Answers = append(r.Answers,
+ dnsmessage.Resource{
+ Header: dnsmessage.ResourceHeader{
+ Name: dnsmessage.MustNewName("<html>.golang.org."),
+ Type: dnsmessage.TypePTR,
+ Class: dnsmessage.ClassINET,
+ Length: 4,
+ },
+ Body: &dnsmessage.PTRResource{
+ PTR: dnsmessage.MustNewName("<html>.golang.org."),
+ },
+ },
+ )
+ }
+ return r, nil
+ },
+ }
+ r := Resolver{PreferGo: true, Dial: fake.DialContext}
+
+ _, err := r.LookupCNAME(context.Background(), "golang.org")
+ if expected := "lookup golang.org: CNAME target is invalid"; err.Error() != expected {
+ t.Errorf("LookupCNAME returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+ _, _, err = r.LookupSRV(context.Background(), "target", "tcp", "golang.org")
+ if expected := "lookup golang.org: SRV target is invalid"; err.Error() != expected {
+ t.Errorf("LookupSRV returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+ _, _, err = r.LookupSRV(context.Background(), "hdr", "tcp", "golang.org")
+ if expected := "lookup golang.org: SRV header name is invalid"; err.Error() != expected {
+ t.Errorf("LookupSRV returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+ _, err = r.LookupMX(context.Background(), "golang.org")
+ if expected := "lookup golang.org: MX target is invalid"; err.Error() != expected {
+ t.Errorf("LookupMX returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+ _, err = r.LookupNS(context.Background(), "golang.org")
+ if expected := "lookup golang.org: NS target is invalid"; err.Error() != expected {
+ t.Errorf("LookupNS returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+ _, err = r.LookupAddr(context.Background(), "1.2.3.4")
+ if expected := "lookup 1.2.3.4: PTR target is invalid"; err.Error() != expected {
+ t.Errorf("LookupAddr returned unexpected error, got %q, want %q", err.Error(), expected)
+ }
+}
// contain DNS "CNAME" records, as long as host resolves to
// address records.
//
+// The returned canonical name is validated to be a properly
+// formatted presentation-format domain name.
+//
// LookupCNAME uses context.Background internally; to specify the context, use
// Resolver.LookupCNAME.
func LookupCNAME(host string) (cname string, err error) {
// LookupCNAME does not return an error if host does not
// contain DNS "CNAME" records, as long as host resolves to
// address records.
-func (r *Resolver) LookupCNAME(ctx context.Context, host string) (cname string, err error) {
- return r.lookupCNAME(ctx, host)
+//
+// The returned canonical name is validated to be a properly
+// formatted presentation-format domain name.
+func (r *Resolver) LookupCNAME(ctx context.Context, host string) (string, error) {
+ cname, err := r.lookupCNAME(ctx, host)
+ if err != nil {
+ return "", err
+ }
+ if !isDomainName(cname) {
+ return "", &DNSError{Err: "CNAME target is invalid", Name: host}
+ }
+ return cname, nil
}
// LookupSRV tries to resolve an SRV query of the given service,
// That is, it looks up _service._proto.name. To accommodate services
// publishing SRV records under non-standard names, if both service
// and proto are empty strings, LookupSRV looks up name directly.
+//
+// The returned service names are validated to be properly
+// formatted presentation-format domain names.
func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
return DefaultResolver.lookupSRV(context.Background(), service, proto, name)
}
// That is, it looks up _service._proto.name. To accommodate services
// publishing SRV records under non-standard names, if both service
// and proto are empty strings, LookupSRV looks up name directly.
-func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (cname string, addrs []*SRV, err error) {
- return r.lookupSRV(ctx, service, proto, name)
+//
+// The returned service names are validated to be properly
+// formatted presentation-format domain names.
+func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
+ cname, addrs, err := r.lookupSRV(ctx, service, proto, name)
+ if err != nil {
+ return "", nil, err
+ }
+ if cname != "" && !isDomainName(cname) {
+ return "", nil, &DNSError{Err: "SRV header name is invalid", Name: name}
+ }
+ for _, addr := range addrs {
+ if addr == nil {
+ continue
+ }
+ if !isDomainName(addr.Target) {
+ return "", nil, &DNSError{Err: "SRV target is invalid", Name: name}
+ }
+ }
+ return cname, addrs, nil
}
// LookupMX returns the DNS MX records for the given domain name sorted by preference.
//
+// The returned mail server names are validated to be properly
+// formatted presentation-format domain names.
+//
// LookupMX uses context.Background internally; to specify the context, use
// Resolver.LookupMX.
func LookupMX(name string) ([]*MX, error) {
}
// LookupMX returns the DNS MX records for the given domain name sorted by preference.
+//
+// The returned mail server names are validated to be properly
+// formatted presentation-format domain names.
func (r *Resolver) LookupMX(ctx context.Context, name string) ([]*MX, error) {
- return r.lookupMX(ctx, name)
+ records, err := r.lookupMX(ctx, name)
+ if err != nil {
+ return nil, err
+ }
+ for _, mx := range records {
+ if mx == nil {
+ continue
+ }
+ if !isDomainName(mx.Host) {
+ return nil, &DNSError{Err: "MX target is invalid", Name: name}
+ }
+ }
+ return records, nil
}
// LookupNS returns the DNS NS records for the given domain name.
//
+// The returned name server names are validated to be properly
+// formatted presentation-format domain names.
+//
// LookupNS uses context.Background internally; to specify the context, use
// Resolver.LookupNS.
func LookupNS(name string) ([]*NS, error) {
}
// LookupNS returns the DNS NS records for the given domain name.
+//
+// The returned name server names are validated to be properly
+// formatted presentation-format domain names.
func (r *Resolver) LookupNS(ctx context.Context, name string) ([]*NS, error) {
- return r.lookupNS(ctx, name)
+ records, err := r.lookupNS(ctx, name)
+ if err != nil {
+ return nil, err
+ }
+ for _, ns := range records {
+ if ns == nil {
+ continue
+ }
+ if !isDomainName(ns.Host) {
+ return nil, &DNSError{Err: "NS target is invalid", Name: name}
+ }
+ }
+ return records, nil
}
// LookupTXT returns the DNS TXT records for the given domain name.
// LookupAddr performs a reverse lookup for the given address, returning a list
// of names mapping to that address.
-func (r *Resolver) LookupAddr(ctx context.Context, addr string) (names []string, err error) {
- return r.lookupAddr(ctx, addr)
+//
+// The returned names are validated to be properly
+// formatted presentation-format domain names.
+func (r *Resolver) LookupAddr(ctx context.Context, addr string) ([]string, error) {
+ names, err := r.lookupAddr(ctx, addr)
+ if err != nil {
+ return nil, err
+ }
+ for _, name := range names {
+ if !isDomainName(name) {
+ return nil, &DNSError{Err: "PTR target is invalid", Name: addr}
+ }
+ }
+ return names, nil
}