GODRIVER-2311 Ensure unmarshaled BSON values always use distinct underlying byte arrays. (#874)

Author: matthewdale

bson/bsonrw/value_reader.go

@@ -748,7 +748,11 @@ func (vr *valueReader) readBytes(length int32) ([]byte, error) {
 
 	start := vr.offset
 	vr.offset += int64(length)
-	return vr.d[start : start+int64(length)], nil
+
+	b := make([]byte, length)
+	copy(b, vr.d[start:start+int64(length)])
+
+	return b, nil
 }
 
 func (vr *valueReader) appendBytes(dst []byte, length int32) ([]byte, error) {