Commit 0cc9fdbf authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

kasan: introduce poison_kmalloc_large_redzone 

Split out a poison_kmalloc_large_redzone helper from __kasan_kmalloc_large
and use it in the caller's code.

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

Link: https://lkml.kernel.org/r/93317097b668519d76097fb065201b2027436e22.1703024586.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 ce37eec0

mm/kasan/common.c

+23 −18
Original line number Diff line number Diff line
@@ -363,23 +363,12 @@ void * __must_check __kasan_kmalloc(struct kmem_cache *cache, const void *object 
}

EXPORT_SYMBOL(__kasan_kmalloc);



void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,

static inline void poison_kmalloc_large_redzone(const void *ptr, size_t size,

						gfp_t flags)

{

	unsigned long redzone_start;

	unsigned long redzone_end;



	if (gfpflags_allow_blocking(flags))

		kasan_quarantine_reduce();



	if (unlikely(ptr == NULL))

		return NULL;



	/*

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

	 * alloc_pages() 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
@@ -389,12 +378,25 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, 
		kasan_poison_last_granule(ptr, size);



	/* Poison the aligned part of the redzone. */

	redzone_start = round_up((unsigned long)(ptr + size),

				KASAN_GRANULE_SIZE);

	redzone_start = round_up((unsigned long)(ptr + size), KASAN_GRANULE_SIZE);

	redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr));

	kasan_poison((void *)redzone_start, redzone_end - redzone_start,

		     KASAN_PAGE_REDZONE, false);

}



void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,

						gfp_t flags)

{

	if (gfpflags_allow_blocking(flags))

		kasan_quarantine_reduce();



	if (unlikely(ptr == NULL))

		return NULL;



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

	poison_kmalloc_large_redzone(ptr, size, flags);



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

	return (void *)ptr;

}
@@ -402,6 +404,9 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag 
{

	struct slab *slab;



	if (gfpflags_allow_blocking(flags))

		kasan_quarantine_reduce();



	if (unlikely(object == ZERO_SIZE_PTR))

		return (void *)object;
@@ -419,12 +424,12 @@ 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 {

		poison_kmalloc_large_redzone(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,

				  unsigned long ip)