[PATCH v3 06/39] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_*

Andrey Konovalov
2020-09-24T22:51:18Z

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.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
Change-Id: Iac733e2248aa9d29f6fc425d8946ba07cca73ecf
---
Documentation/dev-tools/kasan.rst | 2 +-
lib/test_kasan.c | 2 +-
mm/kasan/common.c | 39 ++++++++++++++++---------------
mm/kasan/generic.c | 14 +++++------
mm/kasan/generic_report.c | 8 +++----
mm/kasan/init.c | 8 +++----
mm/kasan/kasan.h | 4 ++--
mm/kasan/report.c | 10 ++++----
mm/kasan/tags_report.c | 2 +-
9 files changed, 45 insertions(+), 44 deletions(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 38fd5681fade..a3030fc6afe5 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -264,7 +264,7 @@ 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
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 53e953bb1d1d..ddd0b80f24a1 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -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
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index a4b73fa0dd7e..f65c9f792f8f 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -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 kasan_poison_memory(const void *address, size_t size, u8 value)
{
@@ -138,13 +138,13 @@ void kasan_unpoison_memory(const void *address, size_t size)

kasan_poison_memory(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;
}
}

@@ -296,7 +296,7 @@ void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
void kasan_poison_object_data(struct kmem_cache *cache, void *object)
{
kasan_poison_memory(object,
- round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
+ round_up(cache->object_size, KASAN_GRANULE_SIZE),
KASAN_KMALLOC_REDZONE);
}

@@ -368,7 +368,7 @@ 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)
@@ -407,7 +407,7 @@ 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);
kasan_poison_memory(object, rounded_up_size, KASAN_KMALLOC_FREE);

if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||
@@ -440,9 +440,9 @@ 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);
@@ -486,7 +486,7 @@ 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);

kasan_unpoison_memory(ptr, size);
@@ -584,8 +584,8 @@ 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) {
@@ -743,7 +743,7 @@ 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);
kasan_poison_memory(start, size, KASAN_VMALLOC_INVALID);
}

@@ -856,22 +856,22 @@ 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);
@@ -897,7 +897,8 @@ 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)))
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 7006157c674b..ec4417156943 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -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);

kasan_unpoison_memory(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);
diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c
index 6bb3f66992df..7d5b9e5c7cfe 100644
--- a/mm/kasan/generic_report.c
+++ b/mm/kasan/generic_report.c
@@ -34,7 +34,7 @@ void *find_first_bad_addr(void *addr, size_t size)
void *p = addr;

while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p)))
- p += KASAN_SHADOW_SCALE_SIZE;
+ p += KASAN_GRANULE_SIZE;
return p;
}

@@ -46,14 +46,14 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);

/*
- * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look
+ * If shadow byte value is in [0, KASAN_GRANULE_SIZE) we can look
* at the next shadow byte to determine the type of the bad access.
*/
- if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1)
+ if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1)
shadow_addr++;

switch (*shadow_addr) {
- case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
+ case 0 ... KASAN_GRANULE_SIZE - 1:
/*
* In theory it's still possible to see these shadow values
* due to a data race in the kernel code.
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index 9ce8cc5b8621..dfddd6c39fe6 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -442,8 +442,8 @@ void kasan_remove_zero_shadow(void *start, unsigned long size)
end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);

if (WARN_ON((unsigned long)start %
- (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
- WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+ (KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
+ WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
return;

for (; addr < end; addr = next) {
@@ -477,8 +477,8 @@ int kasan_add_zero_shadow(void *start, unsigned long size)
shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);

if (WARN_ON((unsigned long)start %
- (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
- WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+ (KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
+ WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
return -EINVAL;

ret = kasan_populate_early_shadow(shadow_start, shadow_end);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 03450d3b31f7..c31e2c739301 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -5,8 +5,8 @@
#include <linux/kasan.h>
#include <linux/stackdepot.h>

-#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
-#define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1)
+#define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
+#define KASAN_GRANULE_MASK (KASAN_GRANULE_SIZE - 1)

#define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */
#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index c3031b4b4591..fc487ba83931 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -312,24 +312,24 @@ static bool __must_check get_address_stack_frame_info(const void *addr,
return false;

aligned_addr = round_down((unsigned long)addr, sizeof(long));
- mem_ptr = round_down(aligned_addr, KASAN_SHADOW_SCALE_SIZE);
+ mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));

while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
shadow_ptr--;
- mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+ mem_ptr -= KASAN_GRANULE_SIZE;
}

while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
shadow_ptr--;
- mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+ mem_ptr -= KASAN_GRANULE_SIZE;
}

if (shadow_ptr < shadow_bottom)
return false;

- frame = (const unsigned long *)(mem_ptr + KASAN_SHADOW_SCALE_SIZE);
+ frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
frame[0]);
@@ -567,6 +567,6 @@ void kasan_non_canonical_hook(unsigned long addr)
else
bug_type = "maybe wild-memory-access";
pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type,
- orig_addr, orig_addr + KASAN_SHADOW_MASK);
+ orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1);
}
#endif
diff --git a/mm/kasan/tags_report.c b/mm/kasan/tags_report.c
index 5f183501b871..c87d5a343b4e 100644
--- a/mm/kasan/tags_report.c
+++ b/mm/kasan/tags_report.c
@@ -76,7 +76,7 @@ void *find_first_bad_addr(void *addr, size_t size)
void *end = p + size;

while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
- p += KASAN_SHADOW_SCALE_SIZE;
+ p += KASAN_GRANULE_SIZE;
return p;
}

--
2.28.0.681.g6f77f65b4e-goog