On 9/23/22 22:28, Kees Cook wrote:
Round up allocations with kmalloc_size_roundup() so that mempool's use
of ksize() is always accurate and no special handling of the memory is
needed by KASAN, UBSAN_BOUNDS, nor FORTIFY_SOURCE.
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
mm/mempool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/mempool.c b/mm/mempool.c
index 96488b13a1ef..0f3107b28e6b 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -526,7 +526,7 @@ EXPORT_SYMBOL(mempool_free_slab);
*/
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
{
- size_t size = (size_t)pool_data;
+ size_t size = kmalloc_size_roundup((size_t)pool_data);
Hm it is kinda wasteful to call into kmalloc_size_roundup for every
allocation that has the same input. We could do it just once in
mempool_init_node() for adjusting pool->pool_data ?
But looking more closely, I wonder why poison_element() and
kasan_unpoison_element() in mm/mempool.c even have to use
ksize()/__ksize() and not just operate on the requested size (again,
pool->pool_data). If no kmalloc mempool's users use ksize() to write
beyond requested size, then we don't have to unpoison/poison that area
either?
return kmalloc(size, gfp_mask);
}
EXPORT_SYMBOL(mempool_kmalloc);
