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kasan: fix assigning tags twice 

When an object is kmalloc()'ed, two hooks are called: kasan_slab_alloc()
and kasan_kmalloc().  Right now we assign a tag twice, once in each of the
hooks.  Fix it by assigning a tag only in the former hook.

Link: http://lkml.kernel.org/r/ce8c6431da735aa7ec051fd6497153df690eb021.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2019-02-20 22:19:01 -08:00 committed by Linus Torvalds
parent 050c17f239
commit e1db95befb
1 changed files with 17 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
mm/kasan/common.c
View File

@ -361,10 +361,15 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
* get different tags.
*/
static u8 assign_tag(struct kmem_cache *cache, const void *object,
bool init, bool krealloc)
bool init, bool keep_tag)
{
/* Reuse the same tag for krealloc'ed objects. */
if (krealloc)
/*
* 1. When an object is kmalloc()'ed, two hooks are called:
* kasan_slab_alloc() and kasan_kmalloc(). We assign the
* tag only in the first one.
* 2. We reuse the same tag for krealloc'ed objects.
*/
if (keep_tag)
return get_tag(object);
/*
@ -405,12 +410,6 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
return (void *)object;
}
void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object,
gfp_t flags)
{
return kasan_kmalloc(cache, object, cache->object_size, flags);
}
static inline bool shadow_invalid(u8 tag, s8 shadow_byte)
{
if (IS_ENABLED(CONFIG_KASAN_GENERIC))
@ -467,7 +466,7 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
}
static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
size_t size, gfp_t flags, bool krealloc)
size_t size, gfp_t flags, bool keep_tag)
{
unsigned long redzone_start;
unsigned long redzone_end;
@ -485,7 +484,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
KASAN_SHADOW_SCALE_SIZE);
if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
tag = assign_tag(cache, object, false, krealloc);
tag = assign_tag(cache, object, false, keep_tag);
/* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */
kasan_unpoison_shadow(set_tag(object, tag), size);
@ -498,10 +497,16 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
return set_tag(object, tag);
}
void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object,
gfp_t flags)
{
return __kasan_kmalloc(cache, object, cache->object_size, flags, false);
}
void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object,
size_t size, gfp_t flags)
{
return __kasan_kmalloc(cache, object, size, flags, false);
return __kasan_kmalloc(cache, object, size, flags, true);
}
EXPORT_SYMBOL(kasan_kmalloc);