From 7e3b840ac00b9a774c2d481fc0e667e1254b898e Mon Sep 17 00:00:00 2001
From: Scott Wittenburg <scott.wittenburg@kitware.com>
Date: Thu, 17 Aug 2023 17:46:29 -0600
Subject: [PATCH] WIP: safely check size_t -> integer conversion

---
 source/adios2/engine/hdf5/HDF5ReaderP.cpp | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/source/adios2/engine/hdf5/HDF5ReaderP.cpp b/source/adios2/engine/hdf5/HDF5ReaderP.cpp
index cd39481fdf..bacc9dcabb 100644
--- a/source/adios2/engine/hdf5/HDF5ReaderP.cpp
+++ b/source/adios2/engine/hdf5/HDF5ReaderP.cpp
@@ -13,6 +13,8 @@
 
 #include "adios2/helper/adiosFunctions.h" //CSVToVector
 #include "adios2/helper/adiosFunctions.h" //IsHDF5
+#include <limits>
+#include <stdexcept>
 #include <vector>
 
 namespace adios2
@@ -183,7 +185,14 @@ size_t HDF5ReaderP::ReadDataset(hid_t dataSetId, hid_t h5Type, Variable<T> &vari
         if (ret < 0)
             return 0;
 
-        hid_t memDataSpace = H5Screate_simple(ndims, count.data(), NULL);
+        if (ndims > std::numeric_limits<int>::max())
+        {
+            helper::Throw<std::overflow_error>("Engine", "HDF5ReaderP", "ReadDataset",
+                                               "Number of dimensions is too large to be "
+                                               "represented by an int");
+        }
+
+        hid_t memDataSpace = H5Screate_simple(static_cast<int>(ndims), count.data(), NULL);
         interop::HDF5TypeGuard g_mds(memDataSpace, interop::E_H5_SPACE);
 
         int elementsRead = 1;
@@ -261,9 +270,17 @@ void HDF5ReaderP::UseHDFRead(Variable<T> &variable, T *data, hid_t h5Type)
 
     while (ts < variable.m_StepsCount)
     {
+        size_t adiosStep = variableStart + ts;
+        if (adiosStep > std::numeric_limits<int>::max())
+        {
+            helper::Throw<std::overflow_error>("Engine", "HDF5ReaderP", "UseHDFRead",
+                                               "Timestep value is too large to be "
+                                               "represented by an int");
+        }
+
         try
         {
-            m_H5File.SetAdiosStep(variableStart + ts);
+            m_H5File.SetAdiosStep(static_cast<int>(adiosStep));
         }
         catch (std::exception &e)
         {