Commit ce37eec0 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

kasan: clean up and rename ____kasan_kmalloc 

Introduce a new poison_kmalloc_redzone helper function that poisons the
redzone for kmalloc object.

Drop the confusingly named ____kasan_kmalloc function and instead use
poison_kmalloc_redzone along with the other required parts of
____kasan_kmalloc in the callers' code.

This is a preparatory change for the following patches in this series.

Link: https://lkml.kernel.org/r/5881232ad357ec0d59a5b1aefd9e0673a386399a.1703024586.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@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>
Cc: Marco Elver <elver@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b556a462

mm/kasan/common.c

+22 −20
Original line number Diff line number Diff line
@@ -312,26 +312,12 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, 
	return tagged_object;

}



static inline void *____kasan_kmalloc(struct kmem_cache *cache,

static inline void poison_kmalloc_redzone(struct kmem_cache *cache,

				const void *object, size_t size, gfp_t flags)

{

	unsigned long redzone_start;

	unsigned long redzone_end;



	if (gfpflags_allow_blocking(flags))

		kasan_quarantine_reduce();



	if (unlikely(object == NULL))

		return NULL;



	if (is_kfence_address(kasan_reset_tag(object)))

		return (void *)object;



	/*

	 * The object has already been unpoisoned by kasan_slab_alloc() for

	 * kmalloc() or by kasan_krealloc() for krealloc().

	 */



	/*

	 * The redzone has byte-level precision for the generic mode.

	 * Partially poison the last object granule to cover the unaligned
@@ -355,14 +341,25 @@ static inline void *____kasan_kmalloc(struct kmem_cache *cache, 
	if (kasan_stack_collection_enabled() && is_kmalloc_cache(cache))

		kasan_save_alloc_info(cache, (void *)object, flags);



	/* Keep the tag that was set by kasan_slab_alloc(). */

	return (void *)object;

}



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);

	if (gfpflags_allow_blocking(flags))

		kasan_quarantine_reduce();



	if (unlikely(object == NULL))

		return NULL;



	if (is_kfence_address(kasan_reset_tag(object)))

		return (void *)object;



	/* The object has already been unpoisoned by kasan_slab_alloc(). */

	poison_kmalloc_redzone(cache, object, size, flags);



	/* Keep the tag that was set by kasan_slab_alloc(). */

	return (void *)object;

}

EXPORT_SYMBOL(__kasan_kmalloc);
@@ -408,6 +405,9 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag 
	if (unlikely(object == ZERO_SIZE_PTR))

		return (void *)object;



	if (is_kfence_address(kasan_reset_tag(object)))

		return (void *)object;



	/*

	 * Unpoison the object's data.

	 * Part of it might already have been unpoisoned, but it's unknown
@@ -420,8 +420,10 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag 
	/* Piggy-back on kmalloc() instrumentation to poison the redzone. */

	if (unlikely(!slab))

		return __kasan_kmalloc_large(object, size, flags);

	else

		return ____kasan_kmalloc(slab->slab_cache, object, size, flags);

	else {

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

		return (void *)object;

	}

}



bool __kasan_mempool_poison_pages(struct page *page, unsigned int order,