When caller creates new kmem_cache, requested size of kmem_cache will be stored in alloc_size. Later alloc_size will be used by kerenel address sanitizer to mark alloc_size of slab object as accessible and the rest of its size as redzone.
Signed-off-by: Andrey Ryabinin <[email protected]> --- include/linux/slub_def.h | 5 +++++ mm/slab.h | 10 ++++++++++ mm/slab_common.c | 2 ++ mm/slub.c | 1 + 4 files changed, 18 insertions(+) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index d82abd4..b8b8154 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -68,6 +68,11 @@ struct kmem_cache { int object_size; /* The size of an object without meta data */ int offset; /* Free pointer offset. */ int cpu_partial; /* Number of per cpu partial objects to keep around */ + +#ifdef CONFIG_KASAN + int alloc_size; /* actual allocation size kmem_cache_create */ +#endif + struct kmem_cache_order_objects oo; /* Allocation and freeing of slabs */ diff --git a/mm/slab.h b/mm/slab.h index 912af7f..cb2e776 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -260,6 +260,16 @@ static inline void memcg_uncharge_slab(struct kmem_cache *s, int order) } #endif +#ifdef CONFIG_KASAN +static inline void kasan_set_alloc_size(struct kmem_cache *s, size_t size) +{ + s->alloc_size = size; +} +#else +static inline void kasan_set_alloc_size(struct kmem_cache *s, size_t size) { } +#endif + + static inline struct kmem_cache *virt_to_cache(const void *obj) { struct page *page = virt_to_head_page(obj); diff --git a/mm/slab_common.c b/mm/slab_common.c index 8df59b09..f5b52f0 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -147,6 +147,7 @@ do_kmem_cache_create(char *name, size_t object_size, size_t size, size_t align, s->name = name; s->object_size = object_size; s->size = size; + kasan_set_alloc_size(s, object_size); s->align = align; s->ctor = ctor; @@ -409,6 +410,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t siz s->name = name; s->size = s->object_size = size; + kasan_set_alloc_size(s, size); s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); err = __kmem_cache_create(s, flags); diff --git a/mm/slub.c b/mm/slub.c index 3bdd9ac..6ddedf9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3724,6 +3724,7 @@ __kmem_cache_alias(const char *name, size_t size, size_t align, * the complete object on kzalloc. */ s->object_size = max(s->object_size, (int)size); + kasan_set_alloc_size(s, max(s->alloc_size, (int)size)); s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *))); for_each_memcg_cache_index(i) { -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
