chore(access): to avoid panic when decoding location

. #1001088459

Signed-off-by: slasher <shenjie1@oppo.com>

blobstore/common/proto/blob_ext.go

@@ -210,6 +210,11 @@ func DecodeLocation(buf []byte) (Location, int, error) {
 	if val, nn = next(); nn <= 0 {
 		return loc, n, fmt.Errorf("bytes length blobs %d", nn)
 	}
+	// Each slice contains at least three one-byte uvarints.
+	// Avoid panic and excessive allocation on malformed input.
+	if val > 1024 || val > uint64(len(buf)/3) {
+		return loc, n, fmt.Errorf("bytes length blobs %d invalid, buffer %d", nn, len(buf))
+	}
 	length := int(val)
 
 	if length > 0 {

blobstore/common/proto/blob_ext_test.go

@@ -15,6 +15,7 @@
 package proto
 
 import (
+	"encoding/binary"
 	"math"
 	mrand "math/rand"
 	"testing"
@@ -142,6 +143,28 @@ func TestLocationDecodeError(t *testing.T) {
 	}
 }
 
+func TestLocationDecodeInvalidSlicesLength(t *testing.T) {
+	buf := (&Location{}).Encode()
+	buf = buf[:len(buf)-1] // remove the encoded zero slices length
+
+	var encoded [binary.MaxVarintLen64]byte
+	n := binary.PutUvarint(encoded[:], math.MaxUint64)
+	buf = append(buf, encoded[:n]...)
+
+	require.NotPanics(t, func() {
+		_, _, err := DecodeLocation(buf)
+		require.Error(t, err)
+	})
+
+	buf = (&Location{}).Encode()
+	buf = buf[:len(buf)-1]
+	n = binary.PutUvarint(encoded[:], 1024+1)
+	buf = append(buf, encoded[:n]...)
+	buf = append(buf, make([]byte, (1024+1)*3)...)
+	_, _, err := DecodeLocation(buf)
+	require.Error(t, err)
+}
+
 func TestLocationSpread(t *testing.T) {
 	{
 		var loc Location