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mm, kasan: SLAB support

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Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexander Potapenko
2016-03-25 14:21:59 -07:00
committed by Linus Torvalds
parent e6e8379c87
commit 7ed2f9e663
12 changed files with 266 additions and 22 deletions
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102
mm/kasan/kasan.c
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@@ -334,6 +334,59 @@ void kasan_free_pages(struct page *page, unsigned int order)
KASAN_FREE_PAGE);
}
#ifdef CONFIG_SLAB
/*
* Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
* For larger allocations larger redzones are used.
*/
static size_t optimal_redzone(size_t object_size)
{
int rz =
object_size <= 64 - 16 ? 16 :
object_size <= 128 - 32 ? 32 :
object_size <= 512 - 64 ? 64 :
object_size <= 4096 - 128 ? 128 :
object_size <= (1 << 14) - 256 ? 256 :
object_size <= (1 << 15) - 512 ? 512 :
object_size <= (1 << 16) - 1024 ? 1024 : 2048;
return rz;
}
void kasan_cache_create(struct kmem_cache *cache, size_t *size,
unsigned long *flags)
{
int redzone_adjust;
/* Make sure the adjusted size is still less than
* KMALLOC_MAX_CACHE_SIZE.
* TODO: this check is only useful for SLAB, but not SLUB. We'll need
* to skip it for SLUB when it starts using kasan_cache_create().
*/
if (*size > KMALLOC_MAX_CACHE_SIZE -
sizeof(struct kasan_alloc_meta) -
sizeof(struct kasan_free_meta))
return;
*flags |= SLAB_KASAN;
/* Add alloc meta. */
cache->kasan_info.alloc_meta_offset = *size;
*size += sizeof(struct kasan_alloc_meta);
/* Add free meta. */
if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor ||
cache->object_size < sizeof(struct kasan_free_meta)) {
cache->kasan_info.free_meta_offset = *size;
*size += sizeof(struct kasan_free_meta);
}
redzone_adjust = optimal_redzone(cache->object_size) -
(*size - cache->object_size);
if (redzone_adjust > 0)
*size += redzone_adjust;
*size = min(KMALLOC_MAX_CACHE_SIZE,
max(*size,
cache->object_size +
optimal_redzone(cache->object_size)));
}
#endif
void kasan_poison_slab(struct page *page)
{
kasan_poison_shadow(page_address(page),
@@ -351,8 +404,36 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
kasan_poison_shadow(object,
round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
KASAN_KMALLOC_REDZONE);
#ifdef CONFIG_SLAB
if (cache->flags & SLAB_KASAN) {
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
alloc_info->state = KASAN_STATE_INIT;
}
#endif
}
static inline void set_track(struct kasan_track *track)
{
track->cpu = raw_smp_processor_id();
track->pid = current->pid;
track->when = jiffies;
}
#ifdef CONFIG_SLAB
struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
const void *object)
{
return (void *)object + cache->kasan_info.alloc_meta_offset;
}
struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
const void *object)
{
return (void *)object + cache->kasan_info.free_meta_offset;
}
#endif
void kasan_slab_alloc(struct kmem_cache *cache, void *object)
{
kasan_kmalloc(cache, object, cache->object_size);
@@ -367,6 +448,17 @@ void kasan_slab_free(struct kmem_cache *cache, void *object)
if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
return;
#ifdef CONFIG_SLAB
if (cache->flags & SLAB_KASAN) {
struct kasan_free_meta *free_info =
get_free_info(cache, object);
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
alloc_info->state = KASAN_STATE_FREE;
set_track(&free_info->track);
}
#endif
kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
}
@@ -386,6 +478,16 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size)
kasan_unpoison_shadow(object, size);
kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
KASAN_KMALLOC_REDZONE);
#ifdef CONFIG_SLAB
if (cache->flags & SLAB_KASAN) {
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
alloc_info->state = KASAN_STATE_ALLOC;
alloc_info->alloc_size = size;
set_track(&alloc_info->track);
}
#endif
}
EXPORT_SYMBOL(kasan_kmalloc);