What version of Go are you using (go version)?

$ go version  
go version go1.18.1 linux/amd64

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

$ go env
GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOENV="/root/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/root/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/root/go"
GOPRIVATE=""
GOPROXY="https://goproxy.cn,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18.1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build2993232734=/tmp/go-build -gno-record-gcc-switches"

What did you do?

`
Here is TCP DNS payload
hexStream := "00600006850000010001000100000776657273696f6e0462696e640000100003c00c0010000300000000002827392e382e327263312d5265644861742d392e382e322d302e36382e7263312e656c365f31302e38c00c00020003000000000002c00c"

data, _ := hex.DecodeString(hexStream)`

https://github.com/golang/net/blob/1d1ef9303861d099ec7e69ccb17377e0c443542d/dns/dnsmessage/message.go#L2041

• wireshark code here

   case 0x40:
   //Extended label (RFC 2673) 
   switch (component_len & 0x3f) {
  
     case 0x01:
       /* Bitstring label */
     {
       int bit_count;
       int label_len;
       int print_len;
  
       bit_count = tvb_get_guint8(tvb, offset);
       offset++;
       label_len = (bit_count - 1) / 8 + 1;
  
       if (maxname > 0) {
         print_len = g_snprintf(np, maxname, "\\[x");
         if (print_len <= maxname) {
           np      += print_len;
           maxname -= print_len;
         } else {
           /* Nothing printed, as there's no room.
              Suppress all subsequent printing. */
           maxname = 0;
         }
       }
       while (label_len--) {
         if (maxname > 0) {
           print_len = g_snprintf(np, maxname, "%02x",
                                  tvb_get_guint8(tvb, offset));
           if (print_len <= maxname) {
             np      += print_len;
             maxname -= print_len;
           } else {
             /* Nothing printed, as there's no room.
                Suppress all subsequent printing. */
             maxname = 0;
           }
         }
         offset++;
       }
       if (maxname > 0) {
         print_len = g_snprintf(np, maxname, "/%d]", bit_count);
         if (print_len <= maxname) {
           np      += print_len;
           maxname -= print_len;
         } else {
           /* Nothing printed, as there's no room.
              Suppress all subsequent printing. */
           maxname = 0;
         }
       }
     }
     break;
  
     default:
       *name="<Unknown extended label>";
       *name_len = (guint)strlen(*name);
       /* Parsing will probably fail from here on, since the */
       /* label length is unknown... */
       len = offset - start_offset;
       if (len < min_len) {
         THROW(ReportedBoundsError);
       }
       return len;
   }
   break;`
  

What did you expect to see?

What did you see instead?