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| author | Dmitry Vyukov <dvyukov@google.com> | 2018-02-06 15:36:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-06 18:32:43 -0800 |
| commit | 1db0e0f9dd9816e5d018518f933066d7b9bc0e33 (patch) | |
| tree | ff58cbb66f85207a812ad0e60c9eb66f5cef9620 /mm/kasan | |
| parent | 6860f6340c0918cddcd3c9fcf8c36401c8184268 (diff) | |
| download | linux-1db0e0f9dd9816e5d018518f933066d7b9bc0e33.tar.gz | |
kasan: unify code between kasan_slab_free() and kasan_poison_kfree()
Both of these functions deal with freeing of slab objects. However, kasan_poison_kfree() mishandles SLAB_TYPESAFE_BY_RCU (must also not poison such objects) and does not detect double-frees. Unify code between these functions. This solves both of the problems and allows to add more common code (e.g. detection of invalid frees). Link: http://lkml.kernel.org/r/385493d863acf60408be219a021c3c8e27daa96f.1514378558.git.dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
| -rw-r--r-- | mm/kasan/kasan.c | 28 |
1 files changed, 12 insertions, 16 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 77c103748728..578843fab5dc 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -489,21 +489,11 @@ void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags) kasan_kmalloc(cache, object, cache->object_size, flags); } -static void kasan_poison_slab_free(struct kmem_cache *cache, void *object) -{ - unsigned long size = cache->object_size; - unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE); - - /* RCU slabs could be legally used after free within the RCU period */ - if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) - return; - - kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); -} - -bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) +static bool __kasan_slab_free(struct kmem_cache *cache, void *object, + unsigned long ip, bool quarantine) { s8 shadow_byte; + unsigned long rounded_up_size; /* RCU slabs could be legally used after free within the RCU period */ if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) @@ -515,9 +505,10 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) return true; } - kasan_poison_slab_free(cache, object); + rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE); + kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); - if (unlikely(!(cache->flags & SLAB_KASAN))) + if (!quarantine || unlikely(!(cache->flags & SLAB_KASAN))) return false; set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT); @@ -525,6 +516,11 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) return true; } +bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) +{ + return __kasan_slab_free(cache, object, ip, true); +} + void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size, gfp_t flags) { @@ -602,7 +598,7 @@ void kasan_poison_kfree(void *ptr, unsigned long ip) kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), KASAN_FREE_PAGE); } else { - kasan_poison_slab_free(page->slab_cache, ptr); + __kasan_slab_free(page->slab_cache, ptr, ip, false); } } |