Commit d5eff736 authored by Hyeonggon Yoo's avatar Hyeonggon Yoo Committed by Vlastimil Babka
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mm/sl[au]b: check if large object is valid in __ksize() 



If address of large object is not beginning of folio or size of the
folio is too small, it must be invalid. WARN() and return 0 in such
cases.

Cc: Marco Elver <elver@google.com>
Suggested-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent 8dfa9d55

mm/slab_common.c

+6 −1
Original line number Diff line number Diff line
@@ -984,8 +984,13 @@ size_t __ksize(const void *object) 


	folio = virt_to_folio(object);



	if (unlikely(!folio_test_slab(folio)))

	if (unlikely(!folio_test_slab(folio))) {

		if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE))

			return 0;

		if (WARN_ON(object != folio_address(folio)))

			return 0;

		return folio_size(folio);

	}



	return slab_ksize(folio_slab(folio)->slab_cache);

}