One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct dm_stat {
...
struct dm_stat_shared stat_shared[0];
};
Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.
So, replace the following form:
sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared)
with:
struct_size(s, stat_shared, n_entries)
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
return -EOVERFLOW;
- shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
+ shared_alloc_size = struct_size(s, stat_shared, n_entries);
if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
return -EOVERFLOW;