Fix a memory corruption issue in H5S__point_project_simple #2626
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jhendersonHDF
added
Merge - To 1.12
Priority - 0. Blocker ⛔
jhendersonHDF
requested review from
lrknox,
derobins,
byrnHDF,
fortnern,
qkoziol,
vchoi-hdfgroup,
bmribler,
glennsong09,
mattjala and
brtnfld
as code owners
| @@ -2319,7 +2319,7 @@ H5S__point_project_simple(const H5S_t *base_space, H5S_t *new_space, hsize_t *of | |||
| /* Copy over the point's coordinates */ | |||
| HDmemset(new_node->pnt, 0, sizeof(hsize_t) * rank_diff); | |||
| H5MM_memcpy(&new_node->pnt[rank_diff], base_node->pnt, | |||
| (new_space->extent.rank * sizeof(hsize_t))); | |||
| (base_space->extent.rank * sizeof(hsize_t))); | |||
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If you expand the code above, you can see that this block assumes new_space->extent.rank > base_space->extent.rank. This copying code allocates a new_space->extent.rank-sized array of hsize_t for the point coordinates, then offsets into the pnt array by rank_diff which is calculated by new_space->extent.rank - base_space->extent.rank. However, it previously tried copying a new_space->extent.rank amount of points into the array AFTER offsetting into the array, whereas there would only be room left for a base_space->extent.rank amount of points. This issue cropped up with a Developer build that disables free lists, so this issue has likely been around for a long time but went unnoticed because the free lists were allocating enough room that we could happily write over.
| @@ -2319,7 +2319,7 @@ H5S__point_project_simple(const H5S_t *base_space, H5S_t *new_space, hsize_t *of | |||
| /* Copy over the point's coordinates */ | |||
| HDmemset(new_node->pnt, 0, sizeof(hsize_t) * rank_diff); | |||
| H5MM_memcpy(&new_node->pnt[rank_diff], base_node->pnt, | |||
| (new_space->extent.rank * sizeof(hsize_t))); | |||
| (base_space->extent.rank * sizeof(hsize_t))); | |||
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