message: check cursor size in tryParseLongHeader()
diff: @@ -50,6 +50,9 @@ QuicReadCodec::tryParsingVersionNegotiation(BufQueue& queue) {
  folly::Expected<ParsedLongHeader, TransportErrorCode> tryParseLongHeader(
  folly::io::Cursor& cursor,
  QuicNodeType nodeType) {
  + if (cursor.isAtEnd() || !cursor.canAdvance(sizeof(uint8_t))) {
  + return folly::makeUnexpected(TransportErrorCode::PROTOCOL_VIOLATION);
  + }
  auto initialByte = cursor.readBE<uint8_t>();
  auto longHeaderInvariant = parseLongHeaderInvariant(initialByte, cursor);
  if (!longHeaderInvariant) {
  