Commit 29d7355a authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

kasan: save alloc stack traces for mempool 

Update kasan_mempool_unpoison_object to properly poison the redzone and
save alloc strack traces for kmalloc and slab pools.

As a part of this change, split out and use a unpoison_slab_object helper
function from __kasan_slab_alloc.

[nathan@kernel.org: mark unpoison_slab_object() as static]
  Link: https://lkml.kernel.org/r/20231221180042.104694-1-andrey.konovalov@linux.dev
Link: https://lkml.kernel.org/r/05ad235da8347cfe14d496d01b2aaf074b4f607c.1703024586.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
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>
Cc: Marco Elver <elver@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0cc9fdbf

include/linux/kasan.h

+4 −3
Original line number Diff line number Diff line
@@ -303,9 +303,10 @@ void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip); 
 * mempool).

 *

 * This function unpoisons a slab allocation that was previously poisoned via

 * kasan_mempool_poison_object() without initializing its memory. For the

 * tag-based modes, this function does not assign a new tag to the allocation

 * and instead restores the original tags based on the pointer value.

 * kasan_mempool_poison_object() and saves an alloc stack trace for it without

 * initializing the allocation's memory. For the tag-based modes, this function

 * does not assign a new tag to the allocation and instead restores the

 * original tags based on the pointer value.

 *

 * This function operates on all slab allocations including large kmalloc

 * allocations (the ones returned by kmalloc_large() or by kmalloc() with the

mm/kasan/common.c

+40 −10
Original line number Diff line number Diff line
@@ -277,6 +277,20 @@ void __kasan_kfree_large(void *ptr, unsigned long ip) 
	/* The object will be poisoned by kasan_poison_pages(). */

}



static inline void unpoison_slab_object(struct kmem_cache *cache, void *object,

					gfp_t flags, bool init)

{

	/*

	 * Unpoison the whole object. For kmalloc() allocations,

	 * poison_kmalloc_redzone() will do precise poisoning.

	 */

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



	/* Save alloc info (if possible) for non-kmalloc() allocations. */

	if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))

		kasan_save_alloc_info(cache, object, flags);

}



void * __must_check __kasan_slab_alloc(struct kmem_cache *cache,

					void *object, gfp_t flags, bool init)

{
@@ -299,15 +313,8 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, 
	tag = assign_tag(cache, object, false);

	tagged_object = set_tag(object, tag);



	/*

	 * Unpoison the whole object.

	 * For kmalloc() allocations, kasan_kmalloc() will do precise poisoning.

	 */

	kasan_unpoison(tagged_object, cache->object_size, init);



	/* Save alloc info (if possible) for non-kmalloc() allocations. */

	if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache))

		kasan_save_alloc_info(cache, tagged_object, flags);

	/* Unpoison the object and save alloc info for non-kmalloc() allocations. */

	unpoison_slab_object(cache, tagged_object, flags, init);



	return tagged_object;

}
@@ -482,7 +489,30 @@ bool __kasan_mempool_poison_object(void *ptr, unsigned long ip) 


void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip)

{

	struct slab *slab;

	gfp_t flags = 0; /* Might be executing under a lock. */



	if (is_kfence_address(kasan_reset_tag(ptr)))

		return;



	slab = virt_to_slab(ptr);



	/*

	 * This function can be called for large kmalloc allocation that get

	 * their memory from page_alloc.

	 */

	if (unlikely(!slab)) {

		kasan_unpoison(ptr, size, false);

		poison_kmalloc_large_redzone(ptr, size, flags);

		return;

	}



	/* Unpoison the object and save alloc info for non-kmalloc() allocations. */

	unpoison_slab_object(slab->slab_cache, ptr, size, flags);



	/* Poison the redzone and save alloc info for kmalloc() allocations. */

	if (is_kmalloc_cache(slab->slab_cache))

		poison_kmalloc_redzone(slab->slab_cache, ptr, size, flags);

}



bool __kasan_check_byte(const void *address, unsigned long ip)