Commit 1f600626 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* 

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory, but will still use the concept
of memory granules.  Each memory granule maps to a single metadata entry:
8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte
for software tag-based mode, and 16 bytes per one allocation tag for
hardware tag-based mode.

Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and
KASAN_SHADOW_MASK to KASAN_GRANULE_MASK.

Also use MASK when used as a mask, otherwise use SIZE.

No functional changes.

Link: https://lkml.kernel.org/r/939b5754e47f528a6e6a6f28ffc5815d8d128033.1606161801.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Tested-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cebd0eb2

Documentation/dev-tools/kasan.rst

+1 −1
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ Most mappings in vmalloc space are small, requiring less than a full 
page of shadow space. Allocating a full shadow page per mapping would

therefore be wasteful. Furthermore, to ensure that different mappings

use different shadow pages, mappings would have to be aligned to

``KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE``.

``KASAN_GRANULE_SIZE * PAGE_SIZE``.



Instead, we share backing space across multiple mappings. We allocate

a backing page when a mapping in vmalloc space uses a particular page

lib/test_kasan.c

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 


#include "../mm/kasan/kasan.h"



#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)

#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)



/*

 * We assign some test results to these globals to make sure the tests

lib/test_kasan_module.c

+1 −1
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 


#include "../mm/kasan/kasan.h"



#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)

#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)



static noinline void __init copy_user_test(void)

{

mm/kasan/common.c

+20 −19
Original line number Diff line number Diff line
@@ -106,7 +106,7 @@ void *memcpy(void *dest, const void *src, size_t len) 


/*

 * Poisons the shadow memory for 'size' bytes starting from 'addr'.

 * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.

 * Memory addresses should be aligned to KASAN_GRANULE_SIZE.

 */

void poison_range(const void *address, size_t size, u8 value)

{
@@ -138,13 +138,13 @@ void unpoison_range(const void *address, size_t size) 


	poison_range(address, size, tag);



	if (size & KASAN_SHADOW_MASK) {

	if (size & KASAN_GRANULE_MASK) {

		u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);



		if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))

			*shadow = tag;

		else

			*shadow = size & KASAN_SHADOW_MASK;

			*shadow = size & KASAN_GRANULE_MASK;

	}

}
@@ -301,7 +301,7 @@ void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) 
void kasan_poison_object_data(struct kmem_cache *cache, void *object)

{

	poison_range(object,

			round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),

			round_up(cache->object_size, KASAN_GRANULE_SIZE),

			KASAN_KMALLOC_REDZONE);

}
@@ -373,7 +373,7 @@ static inline bool shadow_invalid(u8 tag, s8 shadow_byte) 
{

	if (IS_ENABLED(CONFIG_KASAN_GENERIC))

		return shadow_byte < 0 ||

			shadow_byte >= KASAN_SHADOW_SCALE_SIZE;

			shadow_byte >= KASAN_GRANULE_SIZE;



	/* else CONFIG_KASAN_SW_TAGS: */

	if ((u8)shadow_byte == KASAN_TAG_INVALID)
@@ -412,7 +412,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, 
		return true;

	}



	rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);

	rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE);

	poison_range(object, rounded_up_size, KASAN_KMALLOC_FREE);



	if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||
@@ -445,9 +445,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, 
		return NULL;



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

				KASAN_SHADOW_SCALE_SIZE);

				KASAN_GRANULE_SIZE);

	redzone_end = round_up((unsigned long)object + cache->object_size,

				KASAN_SHADOW_SCALE_SIZE);

				KASAN_GRANULE_SIZE);



	if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))

		tag = assign_tag(cache, object, false, keep_tag);
@@ -491,7 +491,7 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size, 


	page = virt_to_page(ptr);

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

				KASAN_SHADOW_SCALE_SIZE);

				KASAN_GRANULE_SIZE);

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



	unpoison_range(ptr, size);
@@ -589,8 +589,8 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb, 
	shadow_size = nr_shadow_pages << PAGE_SHIFT;

	shadow_end = shadow_start + shadow_size;



	if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||

		WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))

	if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||

		WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))

		return NOTIFY_BAD;



	switch (action) {
@@ -748,7 +748,7 @@ void kasan_poison_vmalloc(const void *start, unsigned long size) 
	if (!is_vmalloc_or_module_addr(start))

		return;



	size = round_up(size, KASAN_SHADOW_SCALE_SIZE);

	size = round_up(size, KASAN_GRANULE_SIZE);

	poison_range(start, size, KASAN_VMALLOC_INVALID);

}
@@ -861,22 +861,22 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end, 
	unsigned long region_start, region_end;

	unsigned long size;



	region_start = ALIGN(start, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);

	region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);

	region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);

	region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);



	free_region_start = ALIGN(free_region_start,

				  PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);

				  PAGE_SIZE * KASAN_GRANULE_SIZE);



	if (start != region_start &&

	    free_region_start < region_start)

		region_start -= PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;

		region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;



	free_region_end = ALIGN_DOWN(free_region_end,

				     PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);

				     PAGE_SIZE * KASAN_GRANULE_SIZE);



	if (end != region_end &&

	    free_region_end > region_end)

		region_end += PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;

		region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;



	shadow_start = kasan_mem_to_shadow((void *)region_start);

	shadow_end = kasan_mem_to_shadow((void *)region_end);
@@ -902,7 +902,8 @@ int kasan_module_alloc(void *addr, size_t size) 
	unsigned long shadow_start;



	shadow_start = (unsigned long)kasan_mem_to_shadow(addr);

	scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;

	scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>

				KASAN_SHADOW_SCALE_SHIFT;

	shadow_size = round_up(scaled_size, PAGE_SIZE);



	if (WARN_ON(!PAGE_ALIGNED(shadow_start)))

mm/kasan/generic.c

+7 −7
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ static __always_inline bool memory_is_poisoned_1(unsigned long addr) 
	s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);



	if (unlikely(shadow_value)) {

		s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;

		s8 last_accessible_byte = addr & KASAN_GRANULE_MASK;

		return unlikely(last_accessible_byte >= shadow_value);

	}
@@ -62,7 +62,7 @@ static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr, 
	 * Access crosses 8(shadow size)-byte boundary. Such access maps

	 * into 2 shadow bytes, so we need to check them both.

	 */

	if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))

	if (unlikely(((addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))

		return *shadow_addr || memory_is_poisoned_1(addr + size - 1);



	return memory_is_poisoned_1(addr + size - 1);
@@ -73,7 +73,7 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) 
	u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);



	/* Unaligned 16-bytes access maps into 3 shadow bytes. */

	if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))

	if (unlikely(!IS_ALIGNED(addr, KASAN_GRANULE_SIZE)))

		return *shadow_addr || memory_is_poisoned_1(addr + 15);



	return *shadow_addr;
@@ -134,7 +134,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr, 
		s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);



		if (unlikely(ret != (unsigned long)last_shadow ||

			((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))

			((long)(last_byte & KASAN_GRANULE_MASK) >= *last_shadow)))

			return true;

	}

	return false;
@@ -200,7 +200,7 @@ void kasan_cache_shutdown(struct kmem_cache *cache) 


static void register_global(struct kasan_global *global)

{

	size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);

	size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);



	unpoison_range(global->beg, global->size);
@@ -274,10 +274,10 @@ EXPORT_SYMBOL(__asan_handle_no_return); 
/* Emitted by compiler to poison alloca()ed objects. */

void __asan_alloca_poison(unsigned long addr, size_t size)

{

	size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);

	size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE);

	size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -

			rounded_up_size;

	size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);

	size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE);



	const void *left_redzone = (const void *)(addr -

			KASAN_ALLOCA_REDZONE_SIZE);