[PATCH v11 22/24] kasan: add __must_check annotations to kasan hooks

Andrey Konovalov
2018-11-19T17:28:08Z

This patch adds __must_check annotations to kasan hooks that return a
pointer to make sure that a tagged pointer always gets propagated.

Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
include/linux/kasan.h | 16 ++++++++++------
mm/kasan/common.c | 14 ++++++++------
2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 8da7b7a4397a..b40ea104dd36 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -49,16 +49,20 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
void kasan_poison_slab(struct page *page);
void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
void kasan_poison_object_data(struct kmem_cache *cache, void *object);
-void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object);
+void * __must_check kasan_init_slab_obj(struct kmem_cache *cache,
+ const void *object);

-void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags);
+void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
+ gfp_t flags);
void kasan_kfree_large(void *ptr, unsigned long ip);
void kasan_poison_kfree(void *ptr, unsigned long ip);
-void *kasan_kmalloc(struct kmem_cache *s, const void *object, size_t size,
- gfp_t flags);
-void *kasan_krealloc(const void *object, size_t new_size, gfp_t flags);
+void * __must_check kasan_kmalloc(struct kmem_cache *s, const void *object,
+ size_t size, gfp_t flags);
+void * __must_check kasan_krealloc(const void *object, size_t new_size,
+ gfp_t flags);

-void *kasan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags);
+void * __must_check kasan_slab_alloc(struct kmem_cache *s, void *object,
+ gfp_t flags);
bool kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip);

struct kasan_cache {
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 195ca385cf7a..ba8e78eb0c67 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -373,7 +373,7 @@ static u8 assign_tag(struct kmem_cache *cache, const void *object, bool new)
#endif
}

-void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
+void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
{
struct kasan_alloc_meta *alloc_info;

@@ -389,7 +389,8 @@ void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
return (void *)object;
}

-void *kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
+void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object,
+ gfp_t flags)
{
return kasan_kmalloc(cache, object, cache->object_size, flags);
}
@@ -449,8 +450,8 @@ 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)
+void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object,
+ size_t size, gfp_t flags)
{
unsigned long redzone_start;
unsigned long redzone_end;
@@ -482,7 +483,8 @@ void *kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
}
EXPORT_SYMBOL(kasan_kmalloc);

-void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
+void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
+ gfp_t flags)
{
struct page *page;
unsigned long redzone_start;
@@ -506,7 +508,7 @@ void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
return (void *)ptr;
}

-void *kasan_krealloc(const void *object, size_t size, gfp_t flags)
+void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags)
{
struct page *page;

--
2.19.1.1215.g8438c0b245-goog