also check metadata version

src/nanoarrow/ipc/reader.c

@@ -237,7 +237,8 @@ static int ArrowIpcArrayStreamReaderNextHeader(
  return ENODATA;
  } else if (bytes_read == 4 && private_data->expected_header_prefix_size == 4) {
  // Special case very, very old IPC streams that used 0x00000000 as the
- // end-of-stream indicator.
+ // end-of-stream indicator. We may want to remove this case at some point:
+ // https://github.com/apache/arrow-nanoarrow/issues/648
  uint32_t last_four_bytes = 0;
  memcpy(&last_four_bytes, private_data->header.data, sizeof(uint32_t));
  if (last_four_bytes == 0) {
@@ -264,6 +265,7 @@ static int ArrowIpcArrayStreamReaderNextHeader(
  NANOARROW_RETURN_NOT_OK(ArrowIpcDecoderPeekHeader(
  &private_data->decoder, input_view, &prefix_size_bytes, &private_data->error));
 
+ // Check for a consistent header prefix size
  if (private_data->expected_header_prefix_size != kExpectedHeaderPrefixSizeNotSet &&
  prefix_size_bytes != private_data->expected_header_prefix_size) {
  ArrowErrorSet(&private_data->error,
@@ -293,8 +295,11 @@ static int ArrowIpcArrayStreamReaderNextHeader(
  input_view.data.data = private_data->header.data;
  input_view.size_bytes = private_data->header.size_bytes;
 
- NANOARROW_RETURN_NOT_OK(ArrowIpcDecoderPeekHeader(
- &private_data->decoder, input_view, &prefix_size_bytes, &private_data->error));
+ int32_t new_prefix_size_bytes;
+ NANOARROW_RETURN_NOT_OK(ArrowIpcDecoderPeekHeader(&private_data->decoder, input_view,
+ &new_prefix_size_bytes,
+ &private_data->error));
+ NANOARROW_DCHECK(new_prefix_size_bytes == 8);
  }
 
  // Read the header bytes
@@ -315,6 +320,15 @@ static int ArrowIpcArrayStreamReaderNextHeader(
  NANOARROW_RETURN_NOT_OK(ArrowIpcDecoderVerifyHeader(&private_data->decoder, input_view,
  &private_data->error));
 
+ // If we have a 4-byte header prefix, make sure the metadata version is V4
+ // (Note that some V4 IPC files have an 8 byte header prefix).
+ if (prefix_size_bytes == 4 &&
+ private_data->decoder.metadata_version != NANOARROW_IPC_METADATA_VERSION_V4) {
+ ArrowErrorSet(&private_data->error,
+ "Header prefix size of four bytes is only allowed for V4 metadata");
+ return EINVAL;
+ }
+
  // Don't decode the message if it's of the wrong type (because the error message
  // is better communicated by the caller)
  if (private_data->decoder.message_type != message_type) {