Commit 1ce9a052 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

kasan: rename and document kasan_(un)poison_object_data 

Rename kasan_unpoison_object_data to kasan_unpoison_new_object and add a
documentation comment.  Do the same for kasan_poison_object_data.

The new names and the comments should suggest the users that these hooks
are intended for internal use by the slab allocator.

The following patch will remove non-slab-internal uses of these hooks.

No functional changes.

[andreyknvl@google.com: update references to renamed functions in comments]
  Link: https://lkml.kernel.org/r/20231221180637.105098-1-andrey.konovalov@linux.dev
Link: https://lkml.kernel.org/r/eab156ebbd635f9635ef67d1a4271f716994e628.1703024586.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 86b15969

include/linux/kasan.h

+27 −8
Original line number Diff line number Diff line
@@ -129,20 +129,39 @@ static __always_inline void kasan_poison_slab(struct slab *slab) 
		__kasan_poison_slab(slab);

}



void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object);

static __always_inline void kasan_unpoison_object_data(struct kmem_cache *cache,

void __kasan_unpoison_new_object(struct kmem_cache *cache, void *object);

/**

 * kasan_unpoison_new_object - Temporarily unpoison a new slab object.

 * @cache: Cache the object belong to.

 * @object: Pointer to the object.

 *

 * This function is intended for the slab allocator's internal use. It

 * temporarily unpoisons an object from a newly allocated slab without doing

 * anything else. The object must later be repoisoned by

 * kasan_poison_new_object().

 */

static __always_inline void kasan_unpoison_new_object(struct kmem_cache *cache,

							void *object)

{

	if (kasan_enabled())

		__kasan_unpoison_object_data(cache, object);

		__kasan_unpoison_new_object(cache, object);

}



void __kasan_poison_object_data(struct kmem_cache *cache, void *object);

static __always_inline void kasan_poison_object_data(struct kmem_cache *cache,

void __kasan_poison_new_object(struct kmem_cache *cache, void *object);

/**

 * kasan_unpoison_new_object - Repoison a new slab object.

 * @cache: Cache the object belong to.

 * @object: Pointer to the object.

 *

 * This function is intended for the slab allocator's internal use. It

 * repoisons an object that was previously unpoisoned by

 * kasan_unpoison_new_object() without doing anything else.

 */

static __always_inline void kasan_poison_new_object(struct kmem_cache *cache,

							void *object)

{

	if (kasan_enabled())

		__kasan_poison_object_data(cache, object);

		__kasan_poison_new_object(cache, object);

}



void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
@@ -342,9 +361,9 @@ static inline bool kasan_unpoison_pages(struct page *page, unsigned int order, 
	return false;

}

static inline void kasan_poison_slab(struct slab *slab) {}

static inline void kasan_unpoison_object_data(struct kmem_cache *cache,

static inline void kasan_unpoison_new_object(struct kmem_cache *cache,

					void *object) {}

static inline void kasan_poison_object_data(struct kmem_cache *cache,

static inline void kasan_poison_new_object(struct kmem_cache *cache,

					void *object) {}

static inline void *kasan_init_slab_obj(struct kmem_cache *cache,

				const void *object)

mm/kasan/common.c

+2 −2
Original line number Diff line number Diff line
@@ -143,12 +143,12 @@ void __kasan_poison_slab(struct slab *slab) 
		     KASAN_SLAB_REDZONE, false);

}



void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object)

void __kasan_unpoison_new_object(struct kmem_cache *cache, void *object)

{

	kasan_unpoison(object, cache->object_size, false);

}



void __kasan_poison_object_data(struct kmem_cache *cache, void *object)

void __kasan_poison_new_object(struct kmem_cache *cache, void *object)

{

	kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE),

			KASAN_SLAB_REDZONE, false);

mm/kasan/shadow.c

+2 −2
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ void kasan_poison(const void *addr, size_t size, u8 value, bool init) 


	/*

	 * Perform shadow offset calculation based on untagged address, as

	 * some of the callers (e.g. kasan_poison_object_data) pass tagged

	 * some of the callers (e.g. kasan_poison_new_object) pass tagged

	 * addresses to this function.

	 */

	addr = kasan_reset_tag(addr);
@@ -170,7 +170,7 @@ void kasan_unpoison(const void *addr, size_t size, bool init) 


	/*

	 * Perform shadow offset calculation based on untagged address, as

	 * some of the callers (e.g. kasan_unpoison_object_data) pass tagged

	 * some of the callers (e.g. kasan_unpoison_new_object) pass tagged

	 * addresses to this function.

	 */

	addr = kasan_reset_tag(addr);

mm/slab.c

+4 −6
Original line number Diff line number Diff line
@@ -2327,11 +2327,9 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct slab *slab) 
		 * They must also be threaded.

		 */

		if (cachep->ctor && !(cachep->flags & SLAB_POISON)) {

			kasan_unpoison_object_data(cachep,

						   objp + obj_offset(cachep));

			kasan_unpoison_new_object(cachep, objp + obj_offset(cachep));

			cachep->ctor(objp + obj_offset(cachep));

			kasan_poison_object_data(

				cachep, objp + obj_offset(cachep));

			kasan_poison_new_object(cachep, objp + obj_offset(cachep));

		}



		if (cachep->flags & SLAB_RED_ZONE) {
@@ -2472,9 +2470,9 @@ static void cache_init_objs(struct kmem_cache *cachep, 


		/* constructor could break poison info */

		if (DEBUG == 0 && cachep->ctor) {

			kasan_unpoison_object_data(cachep, objp);

			kasan_unpoison_new_object(cachep, objp);

			cachep->ctor(objp);

			kasan_poison_object_data(cachep, objp);

			kasan_poison_new_object(cachep, objp);

		}



		if (!shuffled)

mm/slub.c

+2 −2
Original line number Diff line number Diff line
@@ -1860,9 +1860,9 @@ static void *setup_object(struct kmem_cache *s, void *object) 
	setup_object_debug(s, object);

	object = kasan_init_slab_obj(s, object);

	if (unlikely(s->ctor)) {

		kasan_unpoison_object_data(s, object);

		kasan_unpoison_new_object(s, object);

		s->ctor(object);

		kasan_poison_object_data(s, object);

		kasan_poison_new_object(s, object);

	}

	return object;

}