[PATCH v3 00/15] kasan: HW_TAGS tests support and fixes

[PATCH v3 00/15] kasan: HW_TAGS tests support and fixes

[Andrey Konovalov]

This patchset adds support for running KASAN-KUnit tests with the
hardware tag-based mode and also contains a few fixes.

Changes v2->v3:
- Don't call kmalloc(0) when generating random size.
- Use ARRAY_SIZE() in kmem_cache_bulk_alloc() test.
- Print error message when tests are being ran with kasan.mode=off.
- Move _RET_IP_ to inline wrappers for kasan annotations.

Andrey Konovalov (15):
  kasan: prefix global functions with kasan_
  kasan: clarify HW_TAGS impact on TBI
  kasan: clean up comments in tests
  kasan: add macros to simplify checking test constraints
  kasan: add match-all tag tests
  kasan, arm64: allow using KUnit tests with HW_TAGS mode
  kasan: rename CONFIG_TEST_KASAN_MODULE
  kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL
  kasan: adapt kmalloc_uaf2 test to HW_TAGS mode
  kasan: fix memory corruption in kasan_bitops_tags test
  kasan: move _RET_IP_ to inline wrappers
  kasan: fix bug detection via ksize for HW_TAGS mode
  kasan: add proper page allocator tests
  kasan: add a test for kmem_cache_alloc/free_bulk
  kasan: don't run tests when KASAN is not enabled

 Documentation/dev-tools/kasan.rst  |  24 +-
 arch/arm64/include/asm/memory.h    |   1 +
 arch/arm64/include/asm/mte-kasan.h |  12 +
 arch/arm64/kernel/mte.c            |  12 +
 arch/arm64/mm/fault.c              |  16 +-
 include/linux/kasan-checks.h       |   6 +
 include/linux/kasan.h              |  37 ++-
 lib/Kconfig.kasan                  |   6 +-
 lib/Makefile                       |   2 +-
 lib/test_kasan.c                   | 424 +++++++++++++++++++++--------
 lib/test_kasan_module.c            |   5 +-
 mm/kasan/common.c                  |  56 ++--
 mm/kasan/generic.c                 |  38 +--
 mm/kasan/kasan.h                   |  69 +++--
 mm/kasan/quarantine.c              |  22 +-
 mm/kasan/report.c                  |  15 +-
 mm/kasan/report_generic.c          |   8 +-
 mm/kasan/report_hw_tags.c          |   8 +-
 mm/kasan/report_sw_tags.c          |   8 +-
 mm/kasan/shadow.c                  |  26 +-
 mm/kasan/sw_tags.c                 |  20 +-
 mm/mempool.c                       |   2 +-
 mm/slab.c                          |   2 +-
 mm/slab_common.c                   |  16 +-
 mm/slub.c                          |   4 +-
 tools/objtool/check.c              |   2 +-
 26 files changed, 559 insertions(+), 282 deletions(-)

-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 01/15] kasan: prefix global functions with kasan_

[Andrey Konovalov]

There's a number of internal KASAN functions that are used across multiple
source code files and therefore aren't marked as static inline. To avoid
littering the kernel function names list with generic function names,
prefix all such KASAN functions with kasan_.

As a part of this change:

- Rename internal (un)poison_range() to kasan_(un)poison() (no _range)
  to avoid name collision with a public kasan_unpoison_range().

- Rename check_memory_region() to kasan_check_range(), as it's a more
  fitting name.

Link: https://linux-review.googlesource.com/id/I719cc93483d4ba288a634dba80ee6b7f2809cd26
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/kasan/common.c         | 47 +++++++++++++++++++-------------------
 mm/kasan/generic.c        | 36 ++++++++++++++---------------
 mm/kasan/kasan.h          | 48 +++++++++++++++++++--------------------
 mm/kasan/quarantine.c     | 22 +++++++++---------
 mm/kasan/report.c         | 13 ++++++-----
 mm/kasan/report_generic.c |  8 +++----
 mm/kasan/report_hw_tags.c |  8 +++----
 mm/kasan/report_sw_tags.c |  8 +++----
 mm/kasan/shadow.c         | 26 ++++++++++-----------
 mm/kasan/sw_tags.c        | 16 ++++++-------
 tools/objtool/check.c     |  2 +-
 11 files changed, 117 insertions(+), 117 deletions(-)

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index b25167664ead..eedc3e0fe365 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -60,7 +60,7 @@ void kasan_disable_current(void)
 
 void __kasan_unpoison_range(const void *address, size_t size)
 {
-	unpoison_range(address, size);
+	kasan_unpoison(address, size);
 }
 
 #if CONFIG_KASAN_STACK
@@ -69,7 +69,7 @@ void kasan_unpoison_task_stack(struct task_struct *task)
 {
 	void *base = task_stack_page(task);
 
-	unpoison_range(base, THREAD_SIZE);
+	kasan_unpoison(base, THREAD_SIZE);
 }
 
 /* Unpoison the stack for the current task beyond a watermark sp value. */
@@ -82,7 +82,7 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
 	 */
 	void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
 
-	unpoison_range(base, watermark - base);
+	kasan_unpoison(base, watermark - base);
 }
 #endif /* CONFIG_KASAN_STACK */
 
@@ -105,18 +105,17 @@ void __kasan_alloc_pages(struct page *page, unsigned int order)
 	if (unlikely(PageHighMem(page)))
 		return;
 
-	tag = random_tag();
+	tag = kasan_random_tag();
 	for (i = 0; i < (1 << order); i++)
 		page_kasan_tag_set(page + i, tag);
-	unpoison_range(page_address(page), PAGE_SIZE << order);
+	kasan_unpoison(page_address(page), PAGE_SIZE << order);
 }
 
 void __kasan_free_pages(struct page *page, unsigned int order)
 {
 	if (likely(!PageHighMem(page)))
-		poison_range(page_address(page),
-				PAGE_SIZE << order,
-				KASAN_FREE_PAGE);
+		kasan_poison(page_address(page), PAGE_SIZE << order,
+			     KASAN_FREE_PAGE);
 }
 
 /*
@@ -246,18 +245,18 @@ void __kasan_poison_slab(struct page *page)
 
 	for (i = 0; i < compound_nr(page); i++)
 		page_kasan_tag_reset(page + i);
-	poison_range(page_address(page), page_size(page),
+	kasan_poison(page_address(page), page_size(page),
 		     KASAN_KMALLOC_REDZONE);
 }
 
 void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 {
-	unpoison_range(object, cache->object_size);
+	kasan_unpoison(object, cache->object_size);
 }
 
 void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
 {
-	poison_range(object, cache->object_size, KASAN_KMALLOC_REDZONE);
+	kasan_poison(object, cache->object_size, KASAN_KMALLOC_REDZONE);
 }
 
 /*
@@ -294,7 +293,7 @@ static u8 assign_tag(struct kmem_cache *cache, const void *object,
 	 * set, assign a tag when the object is being allocated (init == false).
 	 */
 	if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
-		return init ? KASAN_TAG_KERNEL : random_tag();
+		return init ? KASAN_TAG_KERNEL : kasan_random_tag();
 
 	/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
 #ifdef CONFIG_SLAB
@@ -305,7 +304,7 @@ static u8 assign_tag(struct kmem_cache *cache, const void *object,
 	 * For SLUB assign a random tag during slab creation, otherwise reuse
 	 * the already assigned tag.
 	 */
-	return init ? random_tag() : get_tag(object);
+	return init ? kasan_random_tag() : get_tag(object);
 #endif
 }
 
@@ -346,12 +345,12 @@ static bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
 	if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
 		return false;
 
-	if (check_invalid_free(tagged_object)) {
+	if (kasan_check_invalid_free(tagged_object)) {
 		kasan_report_invalid_free(tagged_object, ip);
 		return true;
 	}
 
-	poison_range(object, cache->object_size, KASAN_KMALLOC_FREE);
+	kasan_poison(object, cache->object_size, KASAN_KMALLOC_FREE);
 
 	if (!kasan_stack_collection_enabled())
 		return false;
@@ -361,7 +360,7 @@ static bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
 
 	kasan_set_free_info(cache, object, tag);
 
-	return quarantine_put(cache, object);
+	return kasan_quarantine_put(cache, object);
 }
 
 bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
@@ -386,7 +385,7 @@ void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 			kasan_report_invalid_free(ptr, ip);
 			return;
 		}
-		poison_range(ptr, page_size(page), KASAN_FREE_PAGE);
+		kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE);
 	} else {
 		____kasan_slab_free(page->slab_cache, ptr, ip, false);
 	}
@@ -409,7 +408,7 @@ static void *____kasan_kmalloc(struct kmem_cache *cache, const void *object,
 	u8 tag;
 
 	if (gfpflags_allow_blocking(flags))
-		quarantine_reduce();
+		kasan_quarantine_reduce();
 
 	if (unlikely(object == NULL))
 		return NULL;
@@ -421,9 +420,9 @@ static void *____kasan_kmalloc(struct kmem_cache *cache, const void *object,
 	tag = assign_tag(cache, object, false, keep_tag);
 
 	/* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */
-	unpoison_range(set_tag(object, tag), size);
-	poison_range((void *)redzone_start, redzone_end - redzone_start,
-		     KASAN_KMALLOC_REDZONE);
+	kasan_unpoison(set_tag(object, tag), size);
+	kasan_poison((void *)redzone_start, redzone_end - redzone_start,
+			   KASAN_KMALLOC_REDZONE);
 
 	if (kasan_stack_collection_enabled())
 		set_alloc_info(cache, (void *)object, flags);
@@ -452,7 +451,7 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
 	unsigned long redzone_end;
 
 	if (gfpflags_allow_blocking(flags))
-		quarantine_reduce();
+		kasan_quarantine_reduce();
 
 	if (unlikely(ptr == NULL))
 		return NULL;
@@ -462,8 +461,8 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
 				KASAN_GRANULE_SIZE);
 	redzone_end = (unsigned long)ptr + page_size(page);
 
-	unpoison_range(ptr, size);
-	poison_range((void *)redzone_start, redzone_end - redzone_start,
+	kasan_unpoison(ptr, size);
+	kasan_poison((void *)redzone_start, redzone_end - redzone_start,
 		     KASAN_PAGE_REDZONE);
 
 	return (void *)ptr;
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 5106b84b07d4..acab8862dc67 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -158,7 +158,7 @@ static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
 	return memory_is_poisoned_n(addr, size);
 }
 
-static __always_inline bool check_memory_region_inline(unsigned long addr,
+static __always_inline bool check_region_inline(unsigned long addr,
 						size_t size, bool write,
 						unsigned long ret_ip)
 {
@@ -179,13 +179,13 @@ static __always_inline bool check_memory_region_inline(unsigned long addr,
 	return !kasan_report(addr, size, write, ret_ip);
 }
 
-bool check_memory_region(unsigned long addr, size_t size, bool write,
-				unsigned long ret_ip)
+bool kasan_check_range(unsigned long addr, size_t size, bool write,
+					unsigned long ret_ip)
 {
-	return check_memory_region_inline(addr, size, write, ret_ip);
+	return check_region_inline(addr, size, write, ret_ip);
 }
 
-bool check_invalid_free(void *addr)
+bool kasan_check_invalid_free(void *addr)
 {
 	s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
 
@@ -194,22 +194,22 @@ bool check_invalid_free(void *addr)
 
 void kasan_cache_shrink(struct kmem_cache *cache)
 {
-	quarantine_remove_cache(cache);
+	kasan_quarantine_remove_cache(cache);
 }
 
 void kasan_cache_shutdown(struct kmem_cache *cache)
 {
 	if (!__kmem_cache_empty(cache))
-		quarantine_remove_cache(cache);
+		kasan_quarantine_remove_cache(cache);
 }
 
 static void register_global(struct kasan_global *global)
 {
 	size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);
 
-	unpoison_range(global->beg, global->size);
+	kasan_unpoison(global->beg, global->size);
 
-	poison_range(global->beg + aligned_size,
+	kasan_poison(global->beg + aligned_size,
 		     global->size_with_redzone - aligned_size,
 		     KASAN_GLOBAL_REDZONE);
 }
@@ -231,7 +231,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
 #define DEFINE_ASAN_LOAD_STORE(size)					\
 	void __asan_load##size(unsigned long addr)			\
 	{								\
-		check_memory_region_inline(addr, size, false, _RET_IP_);\
+		check_region_inline(addr, size, false, _RET_IP_);	\
 	}								\
 	EXPORT_SYMBOL(__asan_load##size);				\
 	__alias(__asan_load##size)					\
@@ -239,7 +239,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
 	EXPORT_SYMBOL(__asan_load##size##_noabort);			\
 	void __asan_store##size(unsigned long addr)			\
 	{								\
-		check_memory_region_inline(addr, size, true, _RET_IP_);	\
+		check_region_inline(addr, size, true, _RET_IP_);	\
 	}								\
 	EXPORT_SYMBOL(__asan_store##size);				\
 	__alias(__asan_store##size)					\
@@ -254,7 +254,7 @@ DEFINE_ASAN_LOAD_STORE(16);
 
 void __asan_loadN(unsigned long addr, size_t size)
 {
-	check_memory_region(addr, size, false, _RET_IP_);
+	kasan_check_range(addr, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__asan_loadN);
 
@@ -264,7 +264,7 @@ EXPORT_SYMBOL(__asan_loadN_noabort);
 
 void __asan_storeN(unsigned long addr, size_t size)
 {
-	check_memory_region(addr, size, true, _RET_IP_);
+	kasan_check_range(addr, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__asan_storeN);
 
@@ -290,11 +290,11 @@ void __asan_alloca_poison(unsigned long addr, size_t size)
 
 	WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
 
-	unpoison_range((const void *)(addr + rounded_down_size),
-		       size - rounded_down_size);
-	poison_range(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
+	kasan_unpoison((const void *)(addr + rounded_down_size),
+			size - rounded_down_size);
+	kasan_poison(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
 		     KASAN_ALLOCA_LEFT);
-	poison_range(right_redzone, padding_size + KASAN_ALLOCA_REDZONE_SIZE,
+	kasan_poison(right_redzone, padding_size + KASAN_ALLOCA_REDZONE_SIZE,
 		     KASAN_ALLOCA_RIGHT);
 }
 EXPORT_SYMBOL(__asan_alloca_poison);
@@ -305,7 +305,7 @@ void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
 	if (unlikely(!stack_top || stack_top > stack_bottom))
 		return;
 
-	unpoison_range(stack_top, stack_bottom - stack_top);
+	kasan_unpoison(stack_top, stack_bottom - stack_top);
 }
 EXPORT_SYMBOL(__asan_allocas_unpoison);
 
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index cc4d9e1d49b1..3b38baddec47 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -195,14 +195,14 @@ static inline bool addr_has_metadata(const void *addr)
 }
 
 /**
- * check_memory_region - Check memory region, and report if invalid access.
+ * kasan_check_range - Check memory region, and report if invalid access.
  * @addr: the accessed address
  * @size: the accessed size
  * @write: true if access is a write access
  * @ret_ip: return address
  * @return: true if access was valid, false if invalid
  */
-bool check_memory_region(unsigned long addr, size_t size, bool write,
+bool kasan_check_range(unsigned long addr, size_t size, bool write,
 				unsigned long ret_ip);
 
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
@@ -215,19 +215,19 @@ static inline bool addr_has_metadata(const void *addr)
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
-void print_tags(u8 addr_tag, const void *addr);
+void kasan_print_tags(u8 addr_tag, const void *addr);
 #else
-static inline void print_tags(u8 addr_tag, const void *addr) { }
+static inline void kasan_print_tags(u8 addr_tag, const void *addr) { }
 #endif
 
-void *find_first_bad_addr(void *addr, size_t size);
-const char *get_bug_type(struct kasan_access_info *info);
-void metadata_fetch_row(char *buffer, void *row);
+void *kasan_find_first_bad_addr(void *addr, size_t size);
+const char *kasan_get_bug_type(struct kasan_access_info *info);
+void kasan_metadata_fetch_row(char *buffer, void *row);
 
 #if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
-void print_address_stack_frame(const void *addr);
+void kasan_print_address_stack_frame(const void *addr);
 #else
-static inline void print_address_stack_frame(const void *addr) { }
+static inline void kasan_print_address_stack_frame(const void *addr) { }
 #endif
 
 bool kasan_report(unsigned long addr, size_t size,
@@ -244,13 +244,13 @@ struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
 
 #if defined(CONFIG_KASAN_GENERIC) && \
 	(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
-bool quarantine_put(struct kmem_cache *cache, void *object);
-void quarantine_reduce(void);
-void quarantine_remove_cache(struct kmem_cache *cache);
+bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
+void kasan_quarantine_reduce(void);
+void kasan_quarantine_remove_cache(struct kmem_cache *cache);
 #else
-static inline bool quarantine_put(struct kmem_cache *cache, void *object) { return false; }
-static inline void quarantine_reduce(void) { }
-static inline void quarantine_remove_cache(struct kmem_cache *cache) { }
+static inline bool kasan_quarantine_put(struct kmem_cache *cache, void *object) { return false; }
+static inline void kasan_quarantine_reduce(void) { }
+static inline void kasan_quarantine_remove_cache(struct kmem_cache *cache) { }
 #endif
 
 #ifndef arch_kasan_set_tag
@@ -293,28 +293,28 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #endif /* CONFIG_KASAN_HW_TAGS */
 
 #ifdef CONFIG_KASAN_SW_TAGS
-u8 random_tag(void);
+u8 kasan_random_tag(void);
 #elif defined(CONFIG_KASAN_HW_TAGS)
-static inline u8 random_tag(void) { return hw_get_random_tag(); }
+static inline u8 kasan_random_tag(void) { return hw_get_random_tag(); }
 #else
-static inline u8 random_tag(void) { return 0; }
+static inline u8 kasan_random_tag(void) { return 0; }
 #endif
 
 #ifdef CONFIG_KASAN_HW_TAGS
 
-static inline void poison_range(const void *address, size_t size, u8 value)
+static inline void kasan_poison(const void *address, size_t size, u8 value)
 {
 	hw_set_mem_tag_range(kasan_reset_tag(address),
 			round_up(size, KASAN_GRANULE_SIZE), value);
 }
 
-static inline void unpoison_range(const void *address, size_t size)
+static inline void kasan_unpoison(const void *address, size_t size)
 {
 	hw_set_mem_tag_range(kasan_reset_tag(address),
 			round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
 }
 
-static inline bool check_invalid_free(void *addr)
+static inline bool kasan_check_invalid_free(void *addr)
 {
 	u8 ptr_tag = get_tag(addr);
 	u8 mem_tag = hw_get_mem_tag(addr);
@@ -325,9 +325,9 @@ static inline bool check_invalid_free(void *addr)
 
 #else /* CONFIG_KASAN_HW_TAGS */
 
-void poison_range(const void *address, size_t size, u8 value);
-void unpoison_range(const void *address, size_t size);
-bool check_invalid_free(void *addr);
+void kasan_poison(const void *address, size_t size, u8 value);
+void kasan_unpoison(const void *address, size_t size);
+bool kasan_check_invalid_free(void *addr);
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index 55783125a767..728fb24c5683 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -168,7 +168,7 @@ static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
 	qlist_init(q);
 }
 
-bool quarantine_put(struct kmem_cache *cache, void *object)
+bool kasan_quarantine_put(struct kmem_cache *cache, void *object)
 {
 	unsigned long flags;
 	struct qlist_head *q;
@@ -184,11 +184,11 @@ bool quarantine_put(struct kmem_cache *cache, void *object)
 
 	/*
 	 * Note: irq must be disabled until after we move the batch to the
-	 * global quarantine. Otherwise quarantine_remove_cache() can miss
-	 * some objects belonging to the cache if they are in our local temp
-	 * list. quarantine_remove_cache() executes on_each_cpu() at the
-	 * beginning which ensures that it either sees the objects in per-cpu
-	 * lists or in the global quarantine.
+	 * global quarantine. Otherwise kasan_quarantine_remove_cache() can
+	 * miss some objects belonging to the cache if they are in our local
+	 * temp list. kasan_quarantine_remove_cache() executes on_each_cpu()
+	 * at the beginning which ensures that it either sees the objects in
+	 * per-cpu lists or in the global quarantine.
 	 */
 	local_irq_save(flags);
 
@@ -222,7 +222,7 @@ bool quarantine_put(struct kmem_cache *cache, void *object)
 	return true;
 }
 
-void quarantine_reduce(void)
+void kasan_quarantine_reduce(void)
 {
 	size_t total_size, new_quarantine_size, percpu_quarantines;
 	unsigned long flags;
@@ -234,7 +234,7 @@ void quarantine_reduce(void)
 		return;
 
 	/*
-	 * srcu critical section ensures that quarantine_remove_cache()
+	 * srcu critical section ensures that kasan_quarantine_remove_cache()
 	 * will not miss objects belonging to the cache while they are in our
 	 * local to_free list. srcu is chosen because (1) it gives us private
 	 * grace period domain that does not interfere with anything else,
@@ -309,15 +309,15 @@ static void per_cpu_remove_cache(void *arg)
 }
 
 /* Free all quarantined objects belonging to cache. */
-void quarantine_remove_cache(struct kmem_cache *cache)
+void kasan_quarantine_remove_cache(struct kmem_cache *cache)
 {
 	unsigned long flags, i;
 	struct qlist_head to_free = QLIST_INIT;
 
 	/*
 	 * Must be careful to not miss any objects that are being moved from
-	 * per-cpu list to the global quarantine in quarantine_put(),
-	 * nor objects being freed in quarantine_reduce(). on_each_cpu()
+	 * per-cpu list to the global quarantine in kasan_quarantine_put(),
+	 * nor objects being freed in kasan_quarantine_reduce(). on_each_cpu()
 	 * achieves the first goal, while synchronize_srcu() achieves the
 	 * second.
 	 */
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index c0fb21797550..e93d7973792e 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -61,7 +61,7 @@ __setup("kasan_multi_shot", kasan_set_multi_shot);
 static void print_error_description(struct kasan_access_info *info)
 {
 	pr_err("BUG: KASAN: %s in %pS\n",
-		get_bug_type(info), (void *)info->ip);
+		kasan_get_bug_type(info), (void *)info->ip);
 	if (info->access_size)
 		pr_err("%s of size %zu at addr %px by task %s/%d\n",
 			info->is_write ? "Write" : "Read", info->access_size,
@@ -247,7 +247,7 @@ static void print_address_description(void *addr, u8 tag)
 		dump_page(page, "kasan: bad access detected");
 	}
 
-	print_address_stack_frame(addr);
+	kasan_print_address_stack_frame(addr);
 }
 
 static bool meta_row_is_guilty(const void *row, const void *addr)
@@ -293,7 +293,7 @@ static void print_memory_metadata(const void *addr)
 		 * function, because generic functions may try to
 		 * access kasan mapping for the passed address.
 		 */
-		metadata_fetch_row(&metadata[0], row);
+		kasan_metadata_fetch_row(&metadata[0], row);
 
 		print_hex_dump(KERN_ERR, buffer,
 			DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
@@ -350,7 +350,7 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
 
 	start_report(&flags);
 	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);
-	print_tags(tag, object);
+	kasan_print_tags(tag, object);
 	pr_err("\n");
 	print_address_description(object, tag);
 	pr_err("\n");
@@ -378,7 +378,8 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
 
 	info.access_addr = tagged_addr;
 	if (addr_has_metadata(untagged_addr))
-		info.first_bad_addr = find_first_bad_addr(tagged_addr, size);
+		info.first_bad_addr =
+			kasan_find_first_bad_addr(tagged_addr, size);
 	else
 		info.first_bad_addr = untagged_addr;
 	info.access_size = size;
@@ -389,7 +390,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
 
 	print_error_description(&info);
 	if (addr_has_metadata(untagged_addr))
-		print_tags(get_tag(tagged_addr), info.first_bad_addr);
+		kasan_print_tags(get_tag(tagged_addr), info.first_bad_addr);
 	pr_err("\n");
 
 	if (addr_has_metadata(untagged_addr)) {
diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
index 8a9c889872da..41f374585144 100644
--- a/mm/kasan/report_generic.c
+++ b/mm/kasan/report_generic.c
@@ -30,7 +30,7 @@
 #include "kasan.h"
 #include "../slab.h"
 
-void *find_first_bad_addr(void *addr, size_t size)
+void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
 	void *p = addr;
 
@@ -105,7 +105,7 @@ static const char *get_wild_bug_type(struct kasan_access_info *info)
 	return bug_type;
 }
 
-const char *get_bug_type(struct kasan_access_info *info)
+const char *kasan_get_bug_type(struct kasan_access_info *info)
 {
 	/*
 	 * If access_size is a negative number, then it has reason to be
@@ -123,7 +123,7 @@ const char *get_bug_type(struct kasan_access_info *info)
 	return get_wild_bug_type(info);
 }
 
-void metadata_fetch_row(char *buffer, void *row)
+void kasan_metadata_fetch_row(char *buffer, void *row)
 {
 	memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
 }
@@ -263,7 +263,7 @@ static bool __must_check get_address_stack_frame_info(const void *addr,
 	return true;
 }
 
-void print_address_stack_frame(const void *addr)
+void kasan_print_address_stack_frame(const void *addr)
 {
 	unsigned long offset;
 	const char *frame_descr;
diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
index 57114f0e14d1..42b2168755d6 100644
--- a/mm/kasan/report_hw_tags.c
+++ b/mm/kasan/report_hw_tags.c
@@ -15,17 +15,17 @@
 
 #include "kasan.h"
 
-const char *get_bug_type(struct kasan_access_info *info)
+const char *kasan_get_bug_type(struct kasan_access_info *info)
 {
 	return "invalid-access";
 }
 
-void *find_first_bad_addr(void *addr, size_t size)
+void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
 	return kasan_reset_tag(addr);
 }
 
-void metadata_fetch_row(char *buffer, void *row)
+void kasan_metadata_fetch_row(char *buffer, void *row)
 {
 	int i;
 
@@ -33,7 +33,7 @@ void metadata_fetch_row(char *buffer, void *row)
 		buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
 }
 
-void print_tags(u8 addr_tag, const void *addr)
+void kasan_print_tags(u8 addr_tag, const void *addr)
 {
 	u8 memory_tag = hw_get_mem_tag((void *)addr);
 
diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
index 1b026793ad57..3d20d3451d9e 100644
--- a/mm/kasan/report_sw_tags.c
+++ b/mm/kasan/report_sw_tags.c
@@ -29,7 +29,7 @@
 #include "kasan.h"
 #include "../slab.h"
 
-const char *get_bug_type(struct kasan_access_info *info)
+const char *kasan_get_bug_type(struct kasan_access_info *info)
 {
 #ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
 	struct kasan_alloc_meta *alloc_meta;
@@ -72,7 +72,7 @@ const char *get_bug_type(struct kasan_access_info *info)
 	return "invalid-access";
 }
 
-void *find_first_bad_addr(void *addr, size_t size)
+void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
 	u8 tag = get_tag(addr);
 	void *p = kasan_reset_tag(addr);
@@ -83,12 +83,12 @@ void *find_first_bad_addr(void *addr, size_t size)
 	return p;
 }
 
-void metadata_fetch_row(char *buffer, void *row)
+void kasan_metadata_fetch_row(char *buffer, void *row)
 {
 	memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
 }
 
-void print_tags(u8 addr_tag, const void *addr)
+void kasan_print_tags(u8 addr_tag, const void *addr)
 {
 	u8 *shadow = (u8 *)kasan_mem_to_shadow(addr);
 
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 7c2c08c55f32..38958eb0d653 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -27,20 +27,20 @@
 
 bool __kasan_check_read(const volatile void *p, unsigned int size)
 {
-	return check_memory_region((unsigned long)p, size, false, _RET_IP_);
+	return kasan_check_range((unsigned long)p, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__kasan_check_read);
 
 bool __kasan_check_write(const volatile void *p, unsigned int size)
 {
-	return check_memory_region((unsigned long)p, size, true, _RET_IP_);
+	return kasan_check_range((unsigned long)p, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__kasan_check_write);
 
 #undef memset
 void *memset(void *addr, int c, size_t len)
 {
-	if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_))
+	if (!kasan_check_range((unsigned long)addr, len, true, _RET_IP_))
 		return NULL;
 
 	return __memset(addr, c, len);
@@ -50,8 +50,8 @@ void *memset(void *addr, int c, size_t len)
 #undef memmove
 void *memmove(void *dest, const void *src, size_t len)
 {
-	if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
-	    !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
+	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memmove(dest, src, len);
@@ -61,8 +61,8 @@ void *memmove(void *dest, const void *src, size_t len)
 #undef memcpy
 void *memcpy(void *dest, const void *src, size_t len)
 {
-	if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
-	    !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+	if (!kasan_check_range((unsigned long)src, len, false, _RET_IP_) ||
+	    !kasan_check_range((unsigned long)dest, len, true, _RET_IP_))
 		return NULL;
 
 	return __memcpy(dest, src, len);
@@ -72,7 +72,7 @@ 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_GRANULE_SIZE.
  */
-void poison_range(const void *address, size_t size, u8 value)
+void kasan_poison(const void *address, size_t size, u8 value)
 {
 	void *shadow_start, *shadow_end;
 
@@ -90,7 +90,7 @@ void poison_range(const void *address, size_t size, u8 value)
 	__memset(shadow_start, value, shadow_end - shadow_start);
 }
 
-void unpoison_range(const void *address, size_t size)
+void kasan_unpoison(const void *address, size_t size)
 {
 	u8 tag = get_tag(address);
 
@@ -101,7 +101,7 @@ void unpoison_range(const void *address, size_t size)
 	 */
 	address = kasan_reset_tag(address);
 
-	poison_range(address, size, tag);
+	kasan_poison(address, size, tag);
 
 	if (size & KASAN_GRANULE_MASK) {
 		u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
@@ -286,7 +286,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
 	 * // vmalloc() allocates memory
 	 * // let a = area->addr
 	 * // we reach kasan_populate_vmalloc
-	 * // and call unpoison_range:
+	 * // and call kasan_unpoison:
 	 * STORE shadow(a), unpoison_val
 	 * ...
 	 * STORE shadow(a+99), unpoison_val	x = LOAD p
@@ -321,7 +321,7 @@ void kasan_poison_vmalloc(const void *start, unsigned long size)
 		return;
 
 	size = round_up(size, KASAN_GRANULE_SIZE);
-	poison_range(start, size, KASAN_VMALLOC_INVALID);
+	kasan_poison(start, size, KASAN_VMALLOC_INVALID);
 }
 
 void kasan_unpoison_vmalloc(const void *start, unsigned long size)
@@ -329,7 +329,7 @@ void kasan_unpoison_vmalloc(const void *start, unsigned long size)
 	if (!is_vmalloc_or_module_addr(start))
 		return;
 
-	unpoison_range(start, size);
+	kasan_unpoison(start, size);
 }
 
 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index 5dcd830805b2..cc271fceb5d5 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -57,7 +57,7 @@ void __init kasan_init_sw_tags(void)
  * sequence has in fact positive effect, since interrupts that randomly skew
  * PRNG at unpredictable points do only good.
  */
-u8 random_tag(void)
+u8 kasan_random_tag(void)
 {
 	u32 state = this_cpu_read(prng_state);
 
@@ -67,7 +67,7 @@ u8 random_tag(void)
 	return (u8)(state % (KASAN_TAG_MAX + 1));
 }
 
-bool check_memory_region(unsigned long addr, size_t size, bool write,
+bool kasan_check_range(unsigned long addr, size_t size, bool write,
 				unsigned long ret_ip)
 {
 	u8 tag;
@@ -118,7 +118,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write,
 	return true;
 }
 
-bool check_invalid_free(void *addr)
+bool kasan_check_invalid_free(void *addr)
 {
 	u8 tag = get_tag(addr);
 	u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(kasan_reset_tag(addr)));
@@ -130,12 +130,12 @@ bool check_invalid_free(void *addr)
 #define DEFINE_HWASAN_LOAD_STORE(size)					\
 	void __hwasan_load##size##_noabort(unsigned long addr)		\
 	{								\
-		check_memory_region(addr, size, false, _RET_IP_);	\
+		kasan_check_range(addr, size, false, _RET_IP_);	\
 	}								\
 	EXPORT_SYMBOL(__hwasan_load##size##_noabort);			\
 	void __hwasan_store##size##_noabort(unsigned long addr)		\
 	{								\
-		check_memory_region(addr, size, true, _RET_IP_);	\
+		kasan_check_range(addr, size, true, _RET_IP_);		\
 	}								\
 	EXPORT_SYMBOL(__hwasan_store##size##_noabort)
 
@@ -147,19 +147,19 @@ DEFINE_HWASAN_LOAD_STORE(16);
 
 void __hwasan_loadN_noabort(unsigned long addr, unsigned long size)
 {
-	check_memory_region(addr, size, false, _RET_IP_);
+	kasan_check_range(addr, size, false, _RET_IP_);
 }
 EXPORT_SYMBOL(__hwasan_loadN_noabort);
 
 void __hwasan_storeN_noabort(unsigned long addr, unsigned long size)
 {
-	check_memory_region(addr, size, true, _RET_IP_);
+	kasan_check_range(addr, size, true, _RET_IP_);
 }
 EXPORT_SYMBOL(__hwasan_storeN_noabort);
 
 void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size)
 {
-	poison_range((void *)addr, size, tag);
+	kasan_poison((void *)addr, size, tag);
 }
 EXPORT_SYMBOL(__hwasan_tag_memory);
 
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 5f8d3eed78a1..5b2a22591ea7 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -576,7 +576,7 @@ static void add_ignores(struct objtool_file *file)
 static const char *uaccess_safe_builtin[] = {
 	/* KASAN */
 	"kasan_report",
-	"check_memory_region",
+	"kasan_check_range",
 	/* KASAN out-of-line */
 	"__asan_loadN_noabort",
 	"__asan_load1_noabort",
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 02/15] kasan: clarify HW_TAGS impact on TBI

[Andrey Konovalov]

Mention in the documentation that enabling CONFIG_KASAN_HW_TAGS
always results in in-kernel TBI (Top Byte Ignore) being enabled.

Also do a few minor documentation cleanups.

Link: https://linux-review.googlesource.com/id/Iba2a6697e3c6304cb53f89ec61dedc77fa29e3ae
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 Documentation/dev-tools/kasan.rst | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 0fc3fb1860c4..26c99852a852 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -147,15 +147,14 @@ negative values to distinguish between different kinds of inaccessible memory
 like redzones or freed memory (see mm/kasan/kasan.h).
 
 In the report above the arrows point to the shadow byte 03, which means that
-the accessed address is partially accessible.
-
-For tag-based KASAN this last report section shows the memory tags around the
-accessed address (see `Implementation details`_ section).
+the accessed address is partially accessible. For tag-based KASAN modes this
+last report section shows the memory tags around the accessed address
+(see the `Implementation details`_ section).
 
 Boot parameters
 ~~~~~~~~~~~~~~~
 
-Hardware tag-based KASAN mode (see the section about different mode below) is
+Hardware tag-based KASAN mode (see the section about various modes below) is
 intended for use in production as a security mitigation. Therefore it supports
 boot parameters that allow to disable KASAN competely or otherwise control
 particular KASAN features.
@@ -305,6 +304,13 @@ reserved to tag freed memory regions.
 Hardware tag-based KASAN currently only supports tagging of
 kmem_cache_alloc/kmalloc and page_alloc memory.
 
+If the hardware doesn't support MTE (pre ARMv8.5), hardware tag-based KASAN
+won't be enabled. In this case all boot parameters are ignored.
+
+Note, that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI being
+enabled. Even when kasan.mode=off is provided, or when the hardware doesn't
+support MTE (but supports TBI).
+
 What memory accesses are sanitised by KASAN?
 --------------------------------------------
 
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 03/15] kasan: clean up comments in tests

[Andrey Konovalov]

Clarify and update comments in KASAN tests.

Link: https://linux-review.googlesource.com/id/I6c816c51fa1e0eb7aa3dead6bda1f339d2af46c8
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c        | 59 +++++++++++++++++++++++++----------------
 lib/test_kasan_module.c |  5 ++--
 2 files changed, 39 insertions(+), 25 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 2947274cc2d3..6f46e27c2af7 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -28,10 +28,9 @@
 #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
- * are not eliminated as dead code.
+ * Some tests use these global variables to store return values from function
+ * calls that could otherwise be eliminated by the compiler as dead code.
  */
-
 void *kasan_ptr_result;
 int kasan_int_result;
 
@@ -39,14 +38,13 @@ static struct kunit_resource resource;
 static struct kunit_kasan_expectation fail_data;
 static bool multishot;
 
+/*
+ * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
+ * first detected bug and panic the kernel if panic_on_warn is enabled.
+ */
 static int kasan_test_init(struct kunit *test)
 {
-	/*
-	 * Temporarily enable multi-shot mode and set panic_on_warn=0.
-	 * Otherwise, we'd only get a report for the first case.
-	 */
 	multishot = kasan_save_enable_multi_shot();
-
 	return 0;
 }
 
@@ -56,12 +54,12 @@ static void kasan_test_exit(struct kunit *test)
 }
 
 /**
- * KUNIT_EXPECT_KASAN_FAIL() - Causes a test failure when the expression does
- * not cause a KASAN error. This uses a KUnit resource named "kasan_data." Do
- * Do not use this name for a KUnit resource outside here.
- *
+ * KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a
+ * KASAN report; causes a test failure otherwise. This relies on a KUnit
+ * resource named "kasan_data". Do not use this name for KUnit resources
+ * outside of KASAN tests.
  */
-#define KUNIT_EXPECT_KASAN_FAIL(test, condition) do { \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
 	fail_data.report_expected = true; \
 	fail_data.report_found = false; \
 	kunit_add_named_resource(test, \
@@ -69,7 +67,7 @@ static void kasan_test_exit(struct kunit *test)
 				NULL, \
 				&resource, \
 				"kasan_data", &fail_data); \
-	condition; \
+	expression; \
 	KUNIT_EXPECT_EQ(test, \
 			fail_data.report_expected, \
 			fail_data.report_found); \
@@ -121,7 +119,8 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
 		return;
 	}
 
-	/* Allocate a chunk that does not fit into a SLUB cache to trigger
+	/*
+	 * Allocate a chunk that does not fit into a SLUB cache to trigger
 	 * the page allocator fallback.
 	 */
 	ptr = kmalloc(size, GFP_KERNEL);
@@ -168,7 +167,9 @@ static void kmalloc_large_oob_right(struct kunit *test)
 {
 	char *ptr;
 	size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
-	/* Allocate a chunk that is large enough, but still fits into a slab
+
+	/*
+	 * Allocate a chunk that is large enough, but still fits into a slab
 	 * and does not trigger the page allocator fallback in SLUB.
 	 */
 	ptr = kmalloc(size, GFP_KERNEL);
@@ -469,10 +470,13 @@ static void ksize_unpoisons_memory(struct kunit *test)
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 	real_size = ksize(ptr);
-	/* This access doesn't trigger an error. */
+
+	/* This access shouldn't trigger a KASAN report. */
 	ptr[size] = 'x';
-	/* This one does. */
+
+	/* This one must. */
 	KUNIT_EXPECT_KASAN_FAIL(test, ptr[real_size] = 'y');
+
 	kfree(ptr);
 }
 
@@ -568,7 +572,7 @@ static void kmem_cache_invalid_free(struct kunit *test)
 		return;
 	}
 
-	/* Trigger invalid free, the object doesn't get freed */
+	/* Trigger invalid free, the object doesn't get freed. */
 	KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p + 1));
 
 	/*
@@ -585,7 +589,10 @@ static void kasan_memchr(struct kunit *test)
 	char *ptr;
 	size_t size = 24;
 
-	/* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */
+	/*
+	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
+	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
+	 */
 	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 		kunit_info(test,
 			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
@@ -610,7 +617,10 @@ static void kasan_memcmp(struct kunit *test)
 	size_t size = 24;
 	int arr[9];
 
-	/* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */
+	/*
+	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
+	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
+	 */
 	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 		kunit_info(test,
 			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
@@ -634,7 +644,10 @@ static void kasan_strings(struct kunit *test)
 	char *ptr;
 	size_t size = 24;
 
-	/* See https://bugzilla.kernel.org/show_bug.cgi?id=206337 */
+	/*
+	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
+	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
+	 */
 	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
 		kunit_info(test,
 			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
@@ -706,7 +719,7 @@ static void kasan_bitops_generic(struct kunit *test)
 	}
 
 	/*
-	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
+	 * Allocate 1 more byte, which causes kzalloc to round up to 16 bytes;
 	 * this way we do not actually corrupt other memory.
 	 */
 	bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c
index 3b4cc77992d2..eee017ff8980 100644
--- a/lib/test_kasan_module.c
+++ b/lib/test_kasan_module.c
@@ -123,8 +123,9 @@ static noinline void __init kasan_workqueue_uaf(void)
 static int __init test_kasan_module_init(void)
 {
 	/*
-	 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
-	 * report for the first case.
+	 * Temporarily enable multi-shot mode. Otherwise, KASAN would only
+	 * report the first detected bug and panic the kernel if panic_on_warn
+	 * is enabled.
 	 */
 	bool multishot = kasan_save_enable_multi_shot();
 
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 03/15] kasan: clean up comments in tests

[Alexander Potapenko]

On Thu, Jan 14, 2021 at 8:36 PM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> Clarify and update comments in KASAN tests.
>
> Link: https://linux-review.googlesource.com/id/I6c816c51fa1e0eb7aa3dead6bda1f339d2af46c8
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

[PATCH v3 04/15] kasan: add macros to simplify checking test constraints

[Andrey Konovalov]

Some KASAN tests require specific kernel configs to be enabled.
Instead of copy-pasting the checks for these configs add a few helper
macros and use them.

Link: https://linux-review.googlesource.com/id/I237484a7fddfedf4a4aae9cc61ecbcdbe85a0a63
Suggested-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 101 +++++++++++++++--------------------------------
 1 file changed, 31 insertions(+), 70 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 6f46e27c2af7..714ea27fcc3e 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -73,6 +73,20 @@ static void kasan_test_exit(struct kunit *test)
 			fail_data.report_found); \
 } while (0)
 
+#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do {			\
+	if (!IS_ENABLED(config)) {					\
+		kunit_info((test), "skipping, " #config " required");	\
+		return;							\
+	}								\
+} while (0)
+
+#define KASAN_TEST_NEEDS_CONFIG_OFF(test, config) do {			\
+	if (IS_ENABLED(config)) {					\
+		kunit_info((test), "skipping, " #config " enabled");	\
+		return;							\
+	}								\
+} while (0)
+
 static void kmalloc_oob_right(struct kunit *test)
 {
 	char *ptr;
@@ -114,10 +128,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
 	char *ptr;
 	size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
 
-	if (!IS_ENABLED(CONFIG_SLUB)) {
-		kunit_info(test, "CONFIG_SLUB is not enabled.");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
 
 	/*
 	 * Allocate a chunk that does not fit into a SLUB cache to trigger
@@ -135,10 +146,7 @@ static void kmalloc_pagealloc_uaf(struct kunit *test)
 	char *ptr;
 	size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
 
-	if (!IS_ENABLED(CONFIG_SLUB)) {
-		kunit_info(test, "CONFIG_SLUB is not enabled.");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
 
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
@@ -152,10 +160,7 @@ static void kmalloc_pagealloc_invalid_free(struct kunit *test)
 	char *ptr;
 	size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
 
-	if (!IS_ENABLED(CONFIG_SLUB)) {
-		kunit_info(test, "CONFIG_SLUB is not enabled.");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
 
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
@@ -218,10 +223,7 @@ static void kmalloc_oob_16(struct kunit *test)
 	} *ptr1, *ptr2;
 
 	/* This test is specifically crafted for the generic mode. */
-	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
 
 	ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
@@ -454,10 +456,7 @@ static void kasan_global_oob(struct kunit *test)
 	char *p = &global_array[ARRAY_SIZE(global_array) + i];
 
 	/* Only generic mode instruments globals. */
-	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_GENERIC required");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
 
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
@@ -486,10 +485,7 @@ static void kasan_stack_oob(struct kunit *test)
 	volatile int i = OOB_TAG_OFF;
 	char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
 
-	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
-		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
 
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
@@ -501,15 +497,8 @@ static void kasan_alloca_oob_left(struct kunit *test)
 	char *p = alloca_array - 1;
 
 	/* Only generic mode instruments dynamic allocas. */
-	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_GENERIC required");
-		return;
-	}
-
-	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
-		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
 
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
@@ -521,15 +510,8 @@ static void kasan_alloca_oob_right(struct kunit *test)
 	char *p = alloca_array + i;
 
 	/* Only generic mode instruments dynamic allocas. */
-	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_GENERIC required");
-		return;
-	}
-
-	if (!IS_ENABLED(CONFIG_KASAN_STACK)) {
-		kunit_info(test, "CONFIG_KASAN_STACK is not enabled");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK);
 
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
@@ -593,11 +575,7 @@ static void kasan_memchr(struct kunit *test)
 	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
 	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
 	 */
-	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-		kunit_info(test,
-			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
 
 	if (OOB_TAG_OFF)
 		size = round_up(size, OOB_TAG_OFF);
@@ -621,11 +599,7 @@ static void kasan_memcmp(struct kunit *test)
 	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
 	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
 	 */
-	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-		kunit_info(test,
-			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
 
 	if (OOB_TAG_OFF)
 		size = round_up(size, OOB_TAG_OFF);
@@ -648,11 +622,7 @@ static void kasan_strings(struct kunit *test)
 	 * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT.
 	 * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details.
 	 */
-	if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-		kunit_info(test,
-			"str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT);
 
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
@@ -713,10 +683,7 @@ static void kasan_bitops_generic(struct kunit *test)
 	long *bits;
 
 	/* This test is specifically crafted for the generic mode. */
-	if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_GENERIC required\n");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
 
 	/*
 	 * Allocate 1 more byte, which causes kzalloc to round up to 16 bytes;
@@ -744,11 +711,8 @@ static void kasan_bitops_tags(struct kunit *test)
 {
 	long *bits;
 
-	/* This test is specifically crafted for the tag-based mode. */
-	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
-		kunit_info(test, "CONFIG_KASAN_SW_TAGS required\n");
-		return;
-	}
+	/* This test is specifically crafted for tag-based modes. */
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
 
 	/* Allocation size will be rounded to up granule size, which is 16. */
 	bits = kzalloc(sizeof(*bits), GFP_KERNEL);
@@ -777,10 +741,7 @@ static void vmalloc_oob(struct kunit *test)
 {
 	void *area;
 
-	if (!IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
-		kunit_info(test, "CONFIG_KASAN_VMALLOC is not enabled.");
-		return;
-	}
+	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC);
 
 	/*
 	 * We have to be careful not to hit the guard page.
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 05/15] kasan: add match-all tag tests

[Andrey Konovalov]

Add 3 new tests for tag-based KASAN modes:

1. Check that match-all pointer tag is not assigned randomly.
2. Check that 0xff works as a match-all pointer tag.
3. Check that there are no match-all memory tags.

Note, that test #3 causes a significant number (255) of KASAN reports
to be printed during execution for the SW_TAGS mode.

Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++
 mm/kasan/kasan.h |  6 ++++
 2 files changed, 98 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 714ea27fcc3e..c344fe506ffc 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -13,6 +13,7 @@
 #include <linux/mman.h>
 #include <linux/module.h>
 #include <linux/printk.h>
+#include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
@@ -754,6 +755,94 @@ static void vmalloc_oob(struct kunit *test)
 	vfree(area);
 }
 
+/*
+ * Check that the assigned pointer tag falls within the [KASAN_TAG_MIN,
+ * KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based
+ * modes.
+ */
+static void match_all_not_assigned(struct kunit *test)
+{
+	char *ptr;
+	struct page *pages;
+	int i, size, order;
+
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
+
+	for (i = 0; i < 256; i++) {
+		size = (get_random_int() % 1024) + 1;
+		ptr = kmalloc(size, GFP_KERNEL);
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+		KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
+		KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+		kfree(ptr);
+	}
+
+	for (i = 0; i < 256; i++) {
+		order = (get_random_int() % 4) + 1;
+		pages = alloc_pages(GFP_KERNEL, order);
+		ptr = page_address(pages);
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+		KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
+		KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+		free_pages((unsigned long)ptr, order);
+	}
+}
+
+/* Check that 0xff works as a match-all pointer tag for tag-based modes. */
+static void match_all_ptr_tag(struct kunit *test)
+{
+	char *ptr;
+	u8 tag;
+
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
+
+	ptr = kmalloc(128, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+	/* Backup the assigned tag. */
+	tag = get_tag(ptr);
+	KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL);
+
+	/* Reset the tag to 0xff.*/
+	ptr = set_tag(ptr, KASAN_TAG_KERNEL);
+
+	/* This access shouldn't trigger a KASAN report. */
+	*ptr = 0;
+
+	/* Recover the pointer tag and free. */
+	ptr = set_tag(ptr, tag);
+	kfree(ptr);
+}
+
+/* Check that there are no match-all memory tags for tag-based modes. */
+static void match_all_mem_tag(struct kunit *test)
+{
+	char *ptr;
+	int tag;
+
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
+
+	ptr = kmalloc(128, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+	KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL);
+
+	/* For each possible tag value not matching the pointer tag. */
+	for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) {
+		if (tag == get_tag(ptr))
+			continue;
+
+		/* Mark the first memory granule with the chosen memory tag. */
+		kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag);
+
+		/* This access must cause a KASAN report. */
+		KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0);
+	}
+
+	/* Recover the memory tag and free. */
+	kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr));
+	kfree(ptr);
+}
+
 static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kmalloc_oob_right),
 	KUNIT_CASE(kmalloc_oob_left),
@@ -793,6 +882,9 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kasan_bitops_tags),
 	KUNIT_CASE(kmalloc_double_kzfree),
 	KUNIT_CASE(vmalloc_oob),
+	KUNIT_CASE(match_all_not_assigned),
+	KUNIT_CASE(match_all_ptr_tag),
+	KUNIT_CASE(match_all_mem_tag),
 	{}
 };
 
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 3b38baddec47..c3fb9bf241d3 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -36,6 +36,12 @@ extern bool kasan_flag_panic __ro_after_init;
 #define KASAN_TAG_INVALID	0xFE /* inaccessible memory tag */
 #define KASAN_TAG_MAX		0xFD /* maximum value for random tags */
 
+#ifdef CONFIG_KASAN_HW_TAGS
+#define KASAN_TAG_MIN		0xF0 /* mimimum value for random tags */
+#else
+#define KASAN_TAG_MIN		0x00 /* mimimum value for random tags */
+#endif
+
 #ifdef CONFIG_KASAN_GENERIC
 #define KASAN_FREE_PAGE         0xFF  /* page was freed */
 #define KASAN_PAGE_REDZONE      0xFE  /* redzone for kmalloc_large allocations */
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 05/15] kasan: add match-all tag tests

[Alexander Potapenko]

On Thu, Jan 14, 2021 at 8:36 PM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> Add 3 new tests for tag-based KASAN modes:
>
> 1. Check that match-all pointer tag is not assigned randomly.
> 2. Check that 0xff works as a match-all pointer tag.
> 3. Check that there are no match-all memory tags.
>
> Note, that test #3 causes a significant number (255) of KASAN reports
> to be printed during execution for the SW_TAGS mode.
>
> Link: https://linux-review.googlesource.com/id/I78f1375efafa162b37f3abcb2c5bc2f3955dfd8e
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

[PATCH v3 06/15] kasan, arm64: allow using KUnit tests with HW_TAGS mode

[Andrey Konovalov]

On a high level, this patch allows running KUnit KASAN tests with the
hardware tag-based KASAN mode.

Internally, this change reenables tag checking at the end of each KASAN
test that triggers a tag fault and leads to tag checking being disabled.

With this patch KASAN tests are still failing for the hardware tag-based
mode; fixes come in the next few patches.

Link: https://linux-review.googlesource.com/id/Id94dc9eccd33b23cda4950be408c27f879e474c8
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 arch/arm64/include/asm/memory.h    |  1 +
 arch/arm64/include/asm/mte-kasan.h | 12 +++++++++
 arch/arm64/kernel/mte.c            | 12 +++++++++
 arch/arm64/mm/fault.c              | 16 +++++++-----
 lib/Kconfig.kasan                  |  4 +--
 lib/test_kasan.c                   | 42 +++++++++++++++++++++---------
 mm/kasan/kasan.h                   |  9 +++++++
 7 files changed, 75 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 18fce223b67b..cedfc9e97bcc 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -232,6 +232,7 @@ static inline const void *__tag_set(const void *addr, u8 tag)
 
 #ifdef CONFIG_KASAN_HW_TAGS
 #define arch_enable_tagging()			mte_enable_kernel()
+#define arch_set_tagging_report_once(state)	mte_set_report_once(state)
 #define arch_init_tags(max_tag)			mte_init_tags(max_tag)
 #define arch_get_random_tag()			mte_get_random_tag()
 #define arch_get_mem_tag(addr)			mte_get_mem_tag(addr)
diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h
index 26349a4b5e2e..3748d5bb88c0 100644
--- a/arch/arm64/include/asm/mte-kasan.h
+++ b/arch/arm64/include/asm/mte-kasan.h
@@ -32,6 +32,9 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag);
 void mte_enable_kernel(void);
 void mte_init_tags(u64 max_tag);
 
+void mte_set_report_once(bool state);
+bool mte_report_once(void);
+
 #else /* CONFIG_ARM64_MTE */
 
 static inline u8 mte_get_ptr_tag(void *ptr)
@@ -60,6 +63,15 @@ static inline void mte_init_tags(u64 max_tag)
 {
 }
 
+static inline void mte_set_report_once(bool state)
+{
+}
+
+static inline bool mte_report_once(void)
+{
+	return false;
+}
+
 #endif /* CONFIG_ARM64_MTE */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
index dc9ada64feed..c63b3d7a3cd9 100644
--- a/arch/arm64/kernel/mte.c
+++ b/arch/arm64/kernel/mte.c
@@ -25,6 +25,8 @@
 
 u64 gcr_kernel_excl __ro_after_init;
 
+static bool report_fault_once = true;
+
 static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap)
 {
 	pte_t old_pte = READ_ONCE(*ptep);
@@ -158,6 +160,16 @@ void mte_enable_kernel(void)
 	isb();
 }
 
+void mte_set_report_once(bool state)
+{
+	WRITE_ONCE(report_fault_once, state);
+}
+
+bool mte_report_once(void)
+{
+	return READ_ONCE(report_fault_once);
+}
+
 static void update_sctlr_el1_tcf0(u64 tcf0)
 {
 	/* ISB required for the kernel uaccess routines */
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index a218f6f2fdc8..f1b77dc79948 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -302,7 +302,14 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
 static void report_tag_fault(unsigned long addr, unsigned int esr,
 			     struct pt_regs *regs)
 {
-	bool is_write  = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+	static bool reported;
+	bool is_write;
+
+	if (READ_ONCE(reported))
+		return;
+
+	if (mte_report_once())
+		WRITE_ONCE(reported, true);
 
 	/* The format of KASAN tags is 0xF<x>. */
 	addr |= (0xF0UL << MTE_TAG_SHIFT);
@@ -310,6 +317,7 @@ static void report_tag_fault(unsigned long addr, unsigned int esr,
 	 * SAS bits aren't set for all faults reported in EL1, so we can't
 	 * find out access size.
 	 */
+	is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
 	kasan_report(addr, 0, is_write, regs->pc);
 }
 #else
@@ -321,12 +329,8 @@ static inline void report_tag_fault(unsigned long addr, unsigned int esr,
 static void do_tag_recovery(unsigned long addr, unsigned int esr,
 			   struct pt_regs *regs)
 {
-	static bool reported;
 
-	if (!READ_ONCE(reported)) {
-		report_tag_fault(addr, esr, regs);
-		WRITE_ONCE(reported, true);
-	}
+	report_tag_fault(addr, esr, regs);
 
 	/*
 	 * Disable MTE Tag Checking on the local CPU for the current EL.
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index f5fa4ba126bf..3091432acb0a 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -190,11 +190,11 @@ config KASAN_KUNIT_TEST
 	  kernel debugging features like KASAN.
 
 	  For more information on KUnit and unit tests in general, please refer
-	  to the KUnit documentation in Documentation/dev-tools/kunit
+	  to the KUnit documentation in Documentation/dev-tools/kunit.
 
 config TEST_KASAN_MODULE
 	tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
-	depends on m && KASAN
+	depends on m && KASAN && !KASAN_HW_TAGS
 	help
 	  This is a part of the KASAN test suite that is incompatible with
 	  KUnit. Currently includes tests that do bad copy_from/to_user
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c344fe506ffc..ef663bcf83e5 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -41,16 +41,20 @@ static bool multishot;
 
 /*
  * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the
- * first detected bug and panic the kernel if panic_on_warn is enabled.
+ * first detected bug and panic the kernel if panic_on_warn is enabled. For
+ * hardware tag-based KASAN also allow tag checking to be reenabled for each
+ * test, see the comment for KUNIT_EXPECT_KASAN_FAIL().
  */
 static int kasan_test_init(struct kunit *test)
 {
 	multishot = kasan_save_enable_multi_shot();
+	hw_set_tagging_report_once(false);
 	return 0;
 }
 
 static void kasan_test_exit(struct kunit *test)
 {
+	hw_set_tagging_report_once(true);
 	kasan_restore_multi_shot(multishot);
 }
 
@@ -59,19 +63,31 @@ static void kasan_test_exit(struct kunit *test)
  * KASAN report; causes a test failure otherwise. This relies on a KUnit
  * resource named "kasan_data". Do not use this name for KUnit resources
  * outside of KASAN tests.
+ *
+ * For hardware tag-based KASAN, when a tag fault happens, tag checking is
+ * normally auto-disabled. When this happens, this test handler reenables
+ * tag checking. As tag checking can be only disabled or enabled per CPU, this
+ * handler disables migration (preemption).
  */
-#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
-	fail_data.report_expected = true; \
-	fail_data.report_found = false; \
-	kunit_add_named_resource(test, \
-				NULL, \
-				NULL, \
-				&resource, \
-				"kasan_data", &fail_data); \
-	expression; \
-	KUNIT_EXPECT_EQ(test, \
-			fail_data.report_expected, \
-			fail_data.report_found); \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do {		\
+	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS))			\
+		migrate_disable();				\
+	fail_data.report_expected = true;			\
+	fail_data.report_found = false;				\
+	kunit_add_named_resource(test,				\
+				NULL,				\
+				NULL,				\
+				&resource,			\
+				"kasan_data", &fail_data);	\
+	expression;						\
+	KUNIT_EXPECT_EQ(test,					\
+			fail_data.report_expected,		\
+			fail_data.report_found);		\
+	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) {			\
+		if (fail_data.report_found)			\
+			hw_enable_tagging();			\
+		migrate_enable();				\
+	}							\
 } while (0)
 
 #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do {			\
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index c3fb9bf241d3..292dfbc37deb 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -280,6 +280,9 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #ifndef arch_init_tags
 #define arch_init_tags(max_tag)
 #endif
+#ifndef arch_set_tagging_report_once
+#define arch_set_tagging_report_once(state)
+#endif
 #ifndef arch_get_random_tag
 #define arch_get_random_tag()	(0xFF)
 #endif
@@ -292,10 +295,16 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 
 #define hw_enable_tagging()			arch_enable_tagging()
 #define hw_init_tags(max_tag)			arch_init_tags(max_tag)
+#define hw_set_tagging_report_once(state)	arch_set_tagging_report_once(state)
 #define hw_get_random_tag()			arch_get_random_tag()
 #define hw_get_mem_tag(addr)			arch_get_mem_tag(addr)
 #define hw_set_mem_tag_range(addr, size, tag)	arch_set_mem_tag_range((addr), (size), (tag))
 
+#else /* CONFIG_KASAN_HW_TAGS */
+
+#define hw_enable_tagging()
+#define hw_set_tagging_report_once(state)
+
 #endif /* CONFIG_KASAN_HW_TAGS */
 
 #ifdef CONFIG_KASAN_SW_TAGS
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 07/15] kasan: rename CONFIG_TEST_KASAN_MODULE

[Andrey Konovalov]

Rename CONFIG_TEST_KASAN_MODULE to CONFIG_KASAN_MODULE_TEST.

This naming is more consistent with the existing CONFIG_KASAN_KUNIT_TEST.

Link: https://linux-review.googlesource.com/id/Id347dfa5fe8788b7a1a189863e039f409da0ae5f
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 Documentation/dev-tools/kasan.rst | 8 ++++----
 lib/Kconfig.kasan                 | 2 +-
 lib/Makefile                      | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index 26c99852a852..b25ae43d683e 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -374,17 +374,17 @@ unmapped. This will require changes in arch-specific code.
 This allows ``VMAP_STACK`` support on x86, and can simplify support of
 architectures that do not have a fixed module region.
 
-CONFIG_KASAN_KUNIT_TEST & CONFIG_TEST_KASAN_MODULE
---------------------------------------------------
+CONFIG_KASAN_KUNIT_TEST and CONFIG_KASAN_MODULE_TEST
+----------------------------------------------------
 
-KASAN tests consist on two parts:
+KASAN tests consist of two parts:
 
 1. Tests that are integrated with the KUnit Test Framework. Enabled with
 ``CONFIG_KASAN_KUNIT_TEST``. These tests can be run and partially verified
 automatically in a few different ways, see the instructions below.
 
 2. Tests that are currently incompatible with KUnit. Enabled with
-``CONFIG_TEST_KASAN_MODULE`` and can only be run as a module. These tests can
+``CONFIG_KASAN_MODULE_TEST`` and can only be run as a module. These tests can
 only be verified manually, by loading the kernel module and inspecting the
 kernel log for KASAN reports.
 
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 3091432acb0a..624ae1df7984 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -192,7 +192,7 @@ config KASAN_KUNIT_TEST
 	  For more information on KUnit and unit tests in general, please refer
 	  to the KUnit documentation in Documentation/dev-tools/kunit.
 
-config TEST_KASAN_MODULE
+config KASAN_MODULE_TEST
 	tristate "KUnit-incompatible tests of KASAN bug detection capabilities"
 	depends on m && KASAN && !KASAN_HW_TAGS
 	help
diff --git a/lib/Makefile b/lib/Makefile
index afeff05fa8c5..122f25d6407e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -68,7 +68,7 @@ obj-$(CONFIG_TEST_IDA) += test_ida.o
 obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o
 CFLAGS_test_kasan.o += -fno-builtin
 CFLAGS_test_kasan.o += $(call cc-disable-warning, vla)
-obj-$(CONFIG_TEST_KASAN_MODULE) += test_kasan_module.o
+obj-$(CONFIG_KASAN_MODULE_TEST) += test_kasan_module.o
 CFLAGS_test_kasan_module.o += -fno-builtin
 obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o
 CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 08/15] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL

[Andrey Konovalov]

It might not be obvious to the compiler that the expression must be
executed between writing and reading to fail_data. In this case, the
compiler might reorder or optimize away some of the accesses, and
the tests will fail.

Add compiler barriers around the expression in KUNIT_EXPECT_KASAN_FAIL
and use READ/WRITE_ONCE() for accessing fail_data fields.

Link: https://linux-review.googlesource.com/id/I046079f48641a1d36fe627fc8827a9249102fd50
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c  | 17 ++++++++++++-----
 mm/kasan/report.c |  2 +-
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index ef663bcf83e5..2419e36e117b 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -68,23 +68,30 @@ static void kasan_test_exit(struct kunit *test)
  * normally auto-disabled. When this happens, this test handler reenables
  * tag checking. As tag checking can be only disabled or enabled per CPU, this
  * handler disables migration (preemption).
+ *
+ * Since the compiler doesn't see that the expression can change the fail_data
+ * fields, it can reorder or optimize away the accesses to those fields.
+ * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the
+ * expression to prevent that.
  */
 #define KUNIT_EXPECT_KASAN_FAIL(test, expression) do {		\
 	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS))			\
 		migrate_disable();				\
-	fail_data.report_expected = true;			\
-	fail_data.report_found = false;				\
+	WRITE_ONCE(fail_data.report_expected, true);		\
+	WRITE_ONCE(fail_data.report_found, false);		\
 	kunit_add_named_resource(test,				\
 				NULL,				\
 				NULL,				\
 				&resource,			\
 				"kasan_data", &fail_data);	\
+	barrier();						\
 	expression;						\
+	barrier();						\
 	KUNIT_EXPECT_EQ(test,					\
-			fail_data.report_expected,		\
-			fail_data.report_found);		\
+			READ_ONCE(fail_data.report_expected),	\
+			READ_ONCE(fail_data.report_found));	\
 	if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) {			\
-		if (fail_data.report_found)			\
+		if (READ_ONCE(fail_data.report_found))		\
 			hw_enable_tagging();			\
 		migrate_enable();				\
 	}							\
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index e93d7973792e..234f35a84f19 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -331,7 +331,7 @@ static void kasan_update_kunit_status(struct kunit *cur_test)
 	}
 
 	kasan_data = (struct kunit_kasan_expectation *)resource->data;
-	kasan_data->report_found = true;
+	WRITE_ONCE(kasan_data->report_found, true);
 	kunit_put_resource(resource);
 }
 #endif /* IS_ENABLED(CONFIG_KUNIT) */
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 08/15] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL

[Alexander Potapenko]

On Thu, Jan 14, 2021 at 8:36 PM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> It might not be obvious to the compiler that the expression must be
> executed between writing and reading to fail_data. In this case, the
> compiler might reorder or optimize away some of the accesses, and
> the tests will fail.
>
> Add compiler barriers around the expression in KUNIT_EXPECT_KASAN_FAIL
> and use READ/WRITE_ONCE() for accessing fail_data fields.
>
> Link: https://linux-review.googlesource.com/id/I046079f48641a1d36fe627fc8827a9249102fd50
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

[PATCH v3 09/15] kasan: adapt kmalloc_uaf2 test to HW_TAGS mode

[Andrey Konovalov]

In the kmalloc_uaf2() test, the pointers to the two allocated memory
blocks might happen to be the same, and the test will fail. With the
software tag-based mode, the probability of the that is 1/254, so it's
hard to observe the failure. For the hardware tag-based mode though,
the probablity is 1/14, which is quite noticable.

Allow up to 16 attempts at generating different tags for the tag-based
modes.

Link: https://linux-review.googlesource.com/id/Ibfa458ef2804ff465d8eb07434a300bf36388d55
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 2419e36e117b..0cda4a1ff394 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -382,7 +382,9 @@ static void kmalloc_uaf2(struct kunit *test)
 {
 	char *ptr1, *ptr2;
 	size_t size = 43;
+	int counter = 0;
 
+again:
 	ptr1 = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
 
@@ -391,6 +393,15 @@ static void kmalloc_uaf2(struct kunit *test)
 	ptr2 = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
 
+	/*
+	 * For tag-based KASAN ptr1 and ptr2 tags might happen to be the same.
+	 * Allow up to 16 attempts at generating different tags.
+	 */
+	if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && ptr1 == ptr2 && counter++ < 16) {
+		kfree(ptr2);
+		goto again;
+	}
+
 	KUNIT_EXPECT_KASAN_FAIL(test, ptr1[40] = 'x');
 	KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2);
 
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 10/15] kasan: fix memory corruption in kasan_bitops_tags test

[Andrey Konovalov]

Since the hardware tag-based KASAN mode might not have a redzone that
comes after an allocated object (when kasan.mode=prod is enabled), the
kasan_bitops_tags() test ends up corrupting the next object in memory.

Change the test so it always accesses the redzone that lies within the
allocated object's boundaries.

Link: https://linux-review.googlesource.com/id/I67f51d1ee48f0a8d0fe2658c2a39e4879fe0832a
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 0cda4a1ff394..a06e7946f581 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -749,13 +749,13 @@ static void kasan_bitops_tags(struct kunit *test)
 	/* This test is specifically crafted for tag-based modes. */
 	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
 
-	/* Allocation size will be rounded to up granule size, which is 16. */
-	bits = kzalloc(sizeof(*bits), GFP_KERNEL);
+	/* kmalloc-64 cache will be used and the last 16 bytes will be the redzone. */
+	bits = kzalloc(48, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
-	/* Do the accesses past the 16 allocated bytes. */
-	kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]);
-	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, &bits[1]);
+	/* Do the accesses past the 48 allocated bytes, but within the redone. */
+	kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48);
+	kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void *)bits + 48);
 
 	kfree(bits);
 }
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 11/15] kasan: move _RET_IP_ to inline wrappers

[Andrey Konovalov]

Generic mm functions that call KASAN annotations that might report a bug
pass _RET_IP_ to them as an argument. This allows KASAN to include the
name of the function that called the mm function in its report's header.

Now that KASAN has inline wrappers for all of its annotations, move
_RET_IP_ to those wrappers to simplify annotation call sites.

Link: https://linux-review.googlesource.com/id/I8fb3c06d49671305ee184175a39591bc26647a67
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/kasan.h | 20 +++++++++-----------
 mm/mempool.c          |  2 +-
 mm/slab.c             |  2 +-
 mm/slub.c             |  4 ++--
 4 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 5e0655fb2a6f..bba1637827c3 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -181,19 +181,18 @@ static __always_inline void * __must_check kasan_init_slab_obj(
 }
 
 bool __kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip);
-static __always_inline bool kasan_slab_free(struct kmem_cache *s, void *object,
-						unsigned long ip)
+static __always_inline bool kasan_slab_free(struct kmem_cache *s, void *object)
 {
 	if (kasan_enabled())
-		return __kasan_slab_free(s, object, ip);
+		return __kasan_slab_free(s, object, _RET_IP_);
 	return false;
 }
 
 void __kasan_slab_free_mempool(void *ptr, unsigned long ip);
-static __always_inline void kasan_slab_free_mempool(void *ptr, unsigned long ip)
+static __always_inline void kasan_slab_free_mempool(void *ptr)
 {
 	if (kasan_enabled())
-		__kasan_slab_free_mempool(ptr, ip);
+		__kasan_slab_free_mempool(ptr, _RET_IP_);
 }
 
 void * __must_check __kasan_slab_alloc(struct kmem_cache *s,
@@ -237,10 +236,10 @@ static __always_inline void * __must_check kasan_krealloc(const void *object,
 }
 
 void __kasan_kfree_large(void *ptr, unsigned long ip);
-static __always_inline void kasan_kfree_large(void *ptr, unsigned long ip)
+static __always_inline void kasan_kfree_large(void *ptr)
 {
 	if (kasan_enabled())
-		__kasan_kfree_large(ptr, ip);
+		__kasan_kfree_large(ptr, _RET_IP_);
 }
 
 bool kasan_save_enable_multi_shot(void);
@@ -273,12 +272,11 @@ static inline void *kasan_init_slab_obj(struct kmem_cache *cache,
 {
 	return (void *)object;
 }
-static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
-				   unsigned long ip)
+static inline bool kasan_slab_free(struct kmem_cache *s, void *object)
 {
 	return false;
 }
-static inline void kasan_slab_free_mempool(void *ptr, unsigned long ip) {}
+static inline void kasan_slab_free_mempool(void *ptr) {}
 static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object,
 				   gfp_t flags)
 {
@@ -298,7 +296,7 @@ static inline void *kasan_krealloc(const void *object, size_t new_size,
 {
 	return (void *)object;
 }
-static inline void kasan_kfree_large(void *ptr, unsigned long ip) {}
+static inline void kasan_kfree_large(void *ptr) {}
 
 #endif /* CONFIG_KASAN */
 
diff --git a/mm/mempool.c b/mm/mempool.c
index 624ed51b060f..79959fac27d7 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -104,7 +104,7 @@ static inline void poison_element(mempool_t *pool, void *element)
 static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
 {
 	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
-		kasan_slab_free_mempool(element, _RET_IP_);
+		kasan_slab_free_mempool(element);
 	else if (pool->alloc == mempool_alloc_pages)
 		kasan_free_pages(element, (unsigned long)pool->pool_data);
 }
diff --git a/mm/slab.c b/mm/slab.c
index d7c8da9319c7..afeb6191fb1e 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3421,7 +3421,7 @@ static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
 		memset(objp, 0, cachep->object_size);
 
 	/* Put the object into the quarantine, don't touch it for now. */
-	if (kasan_slab_free(cachep, objp, _RET_IP_))
+	if (kasan_slab_free(cachep, objp))
 		return;
 
 	/* Use KCSAN to help debug racy use-after-free. */
diff --git a/mm/slub.c b/mm/slub.c
index 75fb097d990d..0afb53488238 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1514,7 +1514,7 @@ static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
 static __always_inline void kfree_hook(void *x)
 {
 	kmemleak_free(x);
-	kasan_kfree_large(x, _RET_IP_);
+	kasan_kfree_large(x);
 }
 
 static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
@@ -1544,7 +1544,7 @@ static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
 				     KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
 
 	/* KASAN might put x into memory quarantine, delaying its reuse */
-	return kasan_slab_free(s, x, _RET_IP_);
+	return kasan_slab_free(s, x);
 }
 
 static inline bool slab_free_freelist_hook(struct kmem_cache *s,
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 11/15] kasan: move _RET_IP_ to inline wrappers

[Marco Elver]

On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> Generic mm functions that call KASAN annotations that might report a bug
> pass _RET_IP_ to them as an argument. This allows KASAN to include the
> name of the function that called the mm function in its report's header.
> 
> Now that KASAN has inline wrappers for all of its annotations, move
> _RET_IP_ to those wrappers to simplify annotation call sites.
> 
> Link: https://linux-review.googlesource.com/id/I8fb3c06d49671305ee184175a39591bc26647a67
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Much nicer!

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  include/linux/kasan.h | 20 +++++++++-----------
>  mm/mempool.c          |  2 +-
>  mm/slab.c             |  2 +-
>  mm/slub.c             |  4 ++--
>  4 files changed, 13 insertions(+), 15 deletions(-)
> 
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 5e0655fb2a6f..bba1637827c3 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -181,19 +181,18 @@ static __always_inline void * __must_check kasan_init_slab_obj(
>  }
>  
>  bool __kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip);
> -static __always_inline bool kasan_slab_free(struct kmem_cache *s, void *object,
> -						unsigned long ip)
> +static __always_inline bool kasan_slab_free(struct kmem_cache *s, void *object)
>  {
>  	if (kasan_enabled())
> -		return __kasan_slab_free(s, object, ip);
> +		return __kasan_slab_free(s, object, _RET_IP_);
>  	return false;
>  }
>  
>  void __kasan_slab_free_mempool(void *ptr, unsigned long ip);
> -static __always_inline void kasan_slab_free_mempool(void *ptr, unsigned long ip)
> +static __always_inline void kasan_slab_free_mempool(void *ptr)
>  {
>  	if (kasan_enabled())
> -		__kasan_slab_free_mempool(ptr, ip);
> +		__kasan_slab_free_mempool(ptr, _RET_IP_);
>  }
>  
>  void * __must_check __kasan_slab_alloc(struct kmem_cache *s,
> @@ -237,10 +236,10 @@ static __always_inline void * __must_check kasan_krealloc(const void *object,
>  }
>  
>  void __kasan_kfree_large(void *ptr, unsigned long ip);
> -static __always_inline void kasan_kfree_large(void *ptr, unsigned long ip)
> +static __always_inline void kasan_kfree_large(void *ptr)
>  {
>  	if (kasan_enabled())
> -		__kasan_kfree_large(ptr, ip);
> +		__kasan_kfree_large(ptr, _RET_IP_);
>  }
>  
>  bool kasan_save_enable_multi_shot(void);
> @@ -273,12 +272,11 @@ static inline void *kasan_init_slab_obj(struct kmem_cache *cache,
>  {
>  	return (void *)object;
>  }
> -static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
> -				   unsigned long ip)
> +static inline bool kasan_slab_free(struct kmem_cache *s, void *object)
>  {
>  	return false;
>  }
> -static inline void kasan_slab_free_mempool(void *ptr, unsigned long ip) {}
> +static inline void kasan_slab_free_mempool(void *ptr) {}
>  static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object,
>  				   gfp_t flags)
>  {
> @@ -298,7 +296,7 @@ static inline void *kasan_krealloc(const void *object, size_t new_size,
>  {
>  	return (void *)object;
>  }
> -static inline void kasan_kfree_large(void *ptr, unsigned long ip) {}
> +static inline void kasan_kfree_large(void *ptr) {}
>  
>  #endif /* CONFIG_KASAN */
>  
> diff --git a/mm/mempool.c b/mm/mempool.c
> index 624ed51b060f..79959fac27d7 100644
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -104,7 +104,7 @@ static inline void poison_element(mempool_t *pool, void *element)
>  static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
>  {
>  	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
> -		kasan_slab_free_mempool(element, _RET_IP_);
> +		kasan_slab_free_mempool(element);
>  	else if (pool->alloc == mempool_alloc_pages)
>  		kasan_free_pages(element, (unsigned long)pool->pool_data);
>  }
> diff --git a/mm/slab.c b/mm/slab.c
> index d7c8da9319c7..afeb6191fb1e 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3421,7 +3421,7 @@ static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
>  		memset(objp, 0, cachep->object_size);
>  
>  	/* Put the object into the quarantine, don't touch it for now. */
> -	if (kasan_slab_free(cachep, objp, _RET_IP_))
> +	if (kasan_slab_free(cachep, objp))
>  		return;
>  
>  	/* Use KCSAN to help debug racy use-after-free. */
> diff --git a/mm/slub.c b/mm/slub.c
> index 75fb097d990d..0afb53488238 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1514,7 +1514,7 @@ static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
>  static __always_inline void kfree_hook(void *x)
>  {
>  	kmemleak_free(x);
> -	kasan_kfree_large(x, _RET_IP_);
> +	kasan_kfree_large(x);
>  }
>  
>  static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
> @@ -1544,7 +1544,7 @@ static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
>  				     KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
>  
>  	/* KASAN might put x into memory quarantine, delaying its reuse */
> -	return kasan_slab_free(s, x, _RET_IP_);
> +	return kasan_slab_free(s, x);
>  }
>  
>  static inline bool slab_free_freelist_hook(struct kmem_cache *s,
> -- 
> 2.30.0.284.gd98b1dd5eaa7-goog
> 

Re: [PATCH v3 11/15] kasan: move _RET_IP_ to inline wrappers

[Alexander Potapenko]

On Fri, Jan 15, 2021 at 2:19 PM Marco Elver <elver@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> > Generic mm functions that call KASAN annotations that might report a bug
> > pass _RET_IP_ to them as an argument. This allows KASAN to include the
> > name of the function that called the mm function in its report's header.
> >
> > Now that KASAN has inline wrappers for all of its annotations, move
> > _RET_IP_ to those wrappers to simplify annotation call sites.
> >
> > Link: https://linux-review.googlesource.com/id/I8fb3c06d49671305ee184175a39591bc26647a67
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Much nicer!
>
> Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

[PATCH v3 12/15] kasan: fix bug detection via ksize for HW_TAGS mode

[Andrey Konovalov]

The currently existing kasan_check_read/write() annotations are intended
to be used for kernel modules that have KASAN compiler instrumentation
disabled. Thus, they are only relevant for the software KASAN modes that
rely on compiler instrumentation.

However there's another use case for these annotations: ksize() checks
that the object passed to it is indeed accessible before unpoisoning the
whole object. This is currently done via __kasan_check_read(), which is
compiled away for the hardware tag-based mode that doesn't rely on
compiler instrumentation. This leads to KASAN missing detecting some
memory corruptions.

Provide another annotation called kasan_check_byte() that is available
for all KASAN modes. As the implementation rename and reuse
kasan_check_invalid_free(). Use this new annotation in ksize().
To avoid having ksize() as the top frame in the reported stack trace
pass _RET_IP_ to __kasan_check_byte().

Also add a new ksize_uaf() test that checks that a use-after-free is
detected via ksize() itself, and via plain accesses that happen later.

Link: https://linux-review.googlesource.com/id/Iaabf771881d0f9ce1b969f2a62938e99d3308ec5
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/kasan-checks.h |  6 ++++++
 include/linux/kasan.h        | 17 +++++++++++++++++
 lib/test_kasan.c             | 20 ++++++++++++++++++++
 mm/kasan/common.c            | 11 ++++++++++-
 mm/kasan/generic.c           |  4 ++--
 mm/kasan/kasan.h             | 10 +++++-----
 mm/kasan/sw_tags.c           |  6 +++---
 mm/slab_common.c             | 16 +++++++++-------
 8 files changed, 72 insertions(+), 18 deletions(-)

diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
index ca5e89fb10d3..3d6d22a25bdc 100644
--- a/include/linux/kasan-checks.h
+++ b/include/linux/kasan-checks.h
@@ -4,6 +4,12 @@
 
 #include <linux/types.h>
 
+/*
+ * The annotations present in this file are only relevant for the software
+ * KASAN modes that rely on compiler instrumentation, and will be optimized
+ * away for the hardware tag-based KASAN mode. Use kasan_check_byte() instead.
+ */
+
 /*
  * __kasan_check_*: Always available when KASAN is enabled. This may be used
  * even in compilation units that selectively disable KASAN, but must use KASAN
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index bba1637827c3..5bedd5ee481f 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -242,6 +242,19 @@ static __always_inline void kasan_kfree_large(void *ptr)
 		__kasan_kfree_large(ptr, _RET_IP_);
 }
 
+/*
+ * Unlike kasan_check_read/write(), kasan_check_byte() is performed even for
+ * the hardware tag-based mode that doesn't rely on compiler instrumentation.
+ */
+bool __kasan_check_byte(const void *addr, unsigned long ip);
+static __always_inline bool kasan_check_byte(const void *addr)
+{
+	if (kasan_enabled())
+		return __kasan_check_byte(addr, _RET_IP_);
+	return true;
+}
+
+
 bool kasan_save_enable_multi_shot(void);
 void kasan_restore_multi_shot(bool enabled);
 
@@ -297,6 +310,10 @@ static inline void *kasan_krealloc(const void *object, size_t new_size,
 	return (void *)object;
 }
 static inline void kasan_kfree_large(void *ptr) {}
+static inline bool kasan_check_byte(const void *address)
+{
+	return true;
+}
 
 #endif /* CONFIG_KASAN */
 
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index a06e7946f581..566d894ba20b 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -496,6 +496,7 @@ static void kasan_global_oob(struct kunit *test)
 	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
 }
 
+/* Check that ksize() makes the whole object accessible. */
 static void ksize_unpoisons_memory(struct kunit *test)
 {
 	char *ptr;
@@ -514,6 +515,24 @@ static void ksize_unpoisons_memory(struct kunit *test)
 	kfree(ptr);
 }
 
+/*
+ * Check that a use-after-free is detected by ksize() and via normal accesses
+ * after it.
+ */
+static void ksize_uaf(struct kunit *test)
+{
+	char *ptr;
+	int size = 128 - KASAN_GRANULE_SIZE;
+
+	ptr = kmalloc(size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+	kfree(ptr);
+
+	KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr));
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *ptr);
+	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *(ptr + size));
+}
+
 static void kasan_stack_oob(struct kunit *test)
 {
 	char stack_array[10];
@@ -907,6 +926,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kasan_alloca_oob_left),
 	KUNIT_CASE(kasan_alloca_oob_right),
 	KUNIT_CASE(ksize_unpoisons_memory),
+	KUNIT_CASE(ksize_uaf),
 	KUNIT_CASE(kmem_cache_double_free),
 	KUNIT_CASE(kmem_cache_invalid_free),
 	KUNIT_CASE(kasan_memchr),
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index eedc3e0fe365..b18189ef3a92 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -345,7 +345,7 @@ static bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
 	if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
 		return false;
 
-	if (kasan_check_invalid_free(tagged_object)) {
+	if (!kasan_byte_accessible(tagged_object)) {
 		kasan_report_invalid_free(tagged_object, ip);
 		return true;
 	}
@@ -490,3 +490,12 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
 		kasan_report_invalid_free(ptr, ip);
 	/* The object will be poisoned by kasan_free_pages(). */
 }
+
+bool __kasan_check_byte(const void *address, unsigned long ip)
+{
+	if (!kasan_byte_accessible(address)) {
+		kasan_report((unsigned long)address, 1, false, ip);
+		return false;
+	}
+	return true;
+}
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index acab8862dc67..3f17a1218055 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -185,11 +185,11 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 	return check_region_inline(addr, size, write, ret_ip);
 }
 
-bool kasan_check_invalid_free(void *addr)
+bool kasan_byte_accessible(const void *addr)
 {
 	s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
 
-	return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE;
+	return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE;
 }
 
 void kasan_cache_shrink(struct kmem_cache *cache)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 292dfbc37deb..bd4ee6fab648 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -329,20 +329,20 @@ static inline void kasan_unpoison(const void *address, size_t size)
 			round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
 }
 
-static inline bool kasan_check_invalid_free(void *addr)
+static inline bool kasan_byte_accessible(const void *addr)
 {
 	u8 ptr_tag = get_tag(addr);
-	u8 mem_tag = hw_get_mem_tag(addr);
+	u8 mem_tag = hw_get_mem_tag((void *)addr);
 
-	return (mem_tag == KASAN_TAG_INVALID) ||
-		(ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
+	return (mem_tag != KASAN_TAG_INVALID) &&
+		(ptr_tag == KASAN_TAG_KERNEL || ptr_tag == mem_tag);
 }
 
 #else /* CONFIG_KASAN_HW_TAGS */
 
 void kasan_poison(const void *address, size_t size, u8 value);
 void kasan_unpoison(const void *address, size_t size);
-bool kasan_check_invalid_free(void *addr);
+bool kasan_byte_accessible(const void *addr);
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index cc271fceb5d5..94c2d33be333 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -118,13 +118,13 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 	return true;
 }
 
-bool kasan_check_invalid_free(void *addr)
+bool kasan_byte_accessible(const void *addr)
 {
 	u8 tag = get_tag(addr);
 	u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(kasan_reset_tag(addr)));
 
-	return (shadow_byte == KASAN_TAG_INVALID) ||
-		(tag != KASAN_TAG_KERNEL && tag != shadow_byte);
+	return (shadow_byte != KASAN_TAG_INVALID) &&
+		(tag == KASAN_TAG_KERNEL || tag == shadow_byte);
 }
 
 #define DEFINE_HWASAN_LOAD_STORE(size)					\
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e981c80d216c..9c12cf4212ea 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1157,19 +1157,21 @@ size_t ksize(const void *objp)
 	size_t size;
 
 	/*
-	 * We need to check that the pointed to object is valid, and only then
-	 * unpoison the shadow memory below. We use __kasan_check_read(), to
-	 * generate a more useful report at the time ksize() is called (rather
-	 * than later where behaviour is undefined due to potential
-	 * use-after-free or double-free).
+	 * We need to first check that the pointer to the object is valid, and
+	 * only then unpoison the memory. The report printed from ksize() is
+	 * more useful, then when it's printed later when the behaviour could
+	 * be undefined due to a potential use-after-free or double-free.
 	 *
-	 * If the pointed to memory is invalid we return 0, to avoid users of
+	 * We use kasan_check_byte(), which is supported for the hardware
+	 * tag-based KASAN mode, unlike kasan_check_read/write().
+	 *
+	 * If the pointed to memory is invalid, we return 0 to avoid users of
 	 * ksize() writing to and potentially corrupting the memory region.
 	 *
 	 * We want to perform the check before __ksize(), to avoid potentially
 	 * crashing in __ksize() due to accessing invalid metadata.
 	 */
-	if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
+	if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
 		return 0;
 
 	size = __ksize(objp);
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 12/15] kasan: fix bug detection via ksize for HW_TAGS mode

[Marco Elver]

On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> The currently existing kasan_check_read/write() annotations are intended
> to be used for kernel modules that have KASAN compiler instrumentation
> disabled. Thus, they are only relevant for the software KASAN modes that
> rely on compiler instrumentation.
> 
> However there's another use case for these annotations: ksize() checks
> that the object passed to it is indeed accessible before unpoisoning the
> whole object. This is currently done via __kasan_check_read(), which is
> compiled away for the hardware tag-based mode that doesn't rely on
> compiler instrumentation. This leads to KASAN missing detecting some
> memory corruptions.
> 
> Provide another annotation called kasan_check_byte() that is available
> for all KASAN modes. As the implementation rename and reuse
> kasan_check_invalid_free(). Use this new annotation in ksize().
> To avoid having ksize() as the top frame in the reported stack trace
> pass _RET_IP_ to __kasan_check_byte().
> 
> Also add a new ksize_uaf() test that checks that a use-after-free is
> detected via ksize() itself, and via plain accesses that happen later.
> 
> Link: https://linux-review.googlesource.com/id/Iaabf771881d0f9ce1b969f2a62938e99d3308ec5
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  include/linux/kasan-checks.h |  6 ++++++
>  include/linux/kasan.h        | 17 +++++++++++++++++
>  lib/test_kasan.c             | 20 ++++++++++++++++++++
>  mm/kasan/common.c            | 11 ++++++++++-
>  mm/kasan/generic.c           |  4 ++--
>  mm/kasan/kasan.h             | 10 +++++-----
>  mm/kasan/sw_tags.c           |  6 +++---
>  mm/slab_common.c             | 16 +++++++++-------
>  8 files changed, 72 insertions(+), 18 deletions(-)
> 
> diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
> index ca5e89fb10d3..3d6d22a25bdc 100644
> --- a/include/linux/kasan-checks.h
> +++ b/include/linux/kasan-checks.h
> @@ -4,6 +4,12 @@
>  
>  #include <linux/types.h>
>  
> +/*
> + * The annotations present in this file are only relevant for the software
> + * KASAN modes that rely on compiler instrumentation, and will be optimized
> + * away for the hardware tag-based KASAN mode. Use kasan_check_byte() instead.
> + */
> +
>  /*
>   * __kasan_check_*: Always available when KASAN is enabled. This may be used
>   * even in compilation units that selectively disable KASAN, but must use KASAN
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index bba1637827c3..5bedd5ee481f 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -242,6 +242,19 @@ static __always_inline void kasan_kfree_large(void *ptr)
>  		__kasan_kfree_large(ptr, _RET_IP_);
>  }
>  
> +/*
> + * Unlike kasan_check_read/write(), kasan_check_byte() is performed even for
> + * the hardware tag-based mode that doesn't rely on compiler instrumentation.
> + */
> +bool __kasan_check_byte(const void *addr, unsigned long ip);
> +static __always_inline bool kasan_check_byte(const void *addr)
> +{
> +	if (kasan_enabled())
> +		return __kasan_check_byte(addr, _RET_IP_);
> +	return true;
> +}
> +
> +
>  bool kasan_save_enable_multi_shot(void);
>  void kasan_restore_multi_shot(bool enabled);
>  
> @@ -297,6 +310,10 @@ static inline void *kasan_krealloc(const void *object, size_t new_size,
>  	return (void *)object;
>  }
>  static inline void kasan_kfree_large(void *ptr) {}
> +static inline bool kasan_check_byte(const void *address)
> +{
> +	return true;
> +}
>  
>  #endif /* CONFIG_KASAN */
>  
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index a06e7946f581..566d894ba20b 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -496,6 +496,7 @@ static void kasan_global_oob(struct kunit *test)
>  	KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p);
>  }
>  
> +/* Check that ksize() makes the whole object accessible. */
>  static void ksize_unpoisons_memory(struct kunit *test)
>  {
>  	char *ptr;
> @@ -514,6 +515,24 @@ static void ksize_unpoisons_memory(struct kunit *test)
>  	kfree(ptr);
>  }
>  
> +/*
> + * Check that a use-after-free is detected by ksize() and via normal accesses
> + * after it.
> + */
> +static void ksize_uaf(struct kunit *test)
> +{
> +	char *ptr;
> +	int size = 128 - KASAN_GRANULE_SIZE;
> +
> +	ptr = kmalloc(size, GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> +	kfree(ptr);
> +
> +	KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr));
> +	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *ptr);
> +	KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = *(ptr + size));
> +}
> +
>  static void kasan_stack_oob(struct kunit *test)
>  {
>  	char stack_array[10];
> @@ -907,6 +926,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
>  	KUNIT_CASE(kasan_alloca_oob_left),
>  	KUNIT_CASE(kasan_alloca_oob_right),
>  	KUNIT_CASE(ksize_unpoisons_memory),
> +	KUNIT_CASE(ksize_uaf),
>  	KUNIT_CASE(kmem_cache_double_free),
>  	KUNIT_CASE(kmem_cache_invalid_free),
>  	KUNIT_CASE(kasan_memchr),
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index eedc3e0fe365..b18189ef3a92 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -345,7 +345,7 @@ static bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
>  	if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
>  		return false;
>  
> -	if (kasan_check_invalid_free(tagged_object)) {
> +	if (!kasan_byte_accessible(tagged_object)) {
>  		kasan_report_invalid_free(tagged_object, ip);
>  		return true;
>  	}
> @@ -490,3 +490,12 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
>  		kasan_report_invalid_free(ptr, ip);
>  	/* The object will be poisoned by kasan_free_pages(). */
>  }
> +
> +bool __kasan_check_byte(const void *address, unsigned long ip)
> +{
> +	if (!kasan_byte_accessible(address)) {
> +		kasan_report((unsigned long)address, 1, false, ip);
> +		return false;
> +	}
> +	return true;
> +}
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index acab8862dc67..3f17a1218055 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -185,11 +185,11 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
>  	return check_region_inline(addr, size, write, ret_ip);
>  }
>  
> -bool kasan_check_invalid_free(void *addr)
> +bool kasan_byte_accessible(const void *addr)
>  {
>  	s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr));
>  
> -	return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE;
> +	return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE;
>  }
>  
>  void kasan_cache_shrink(struct kmem_cache *cache)
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 292dfbc37deb..bd4ee6fab648 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -329,20 +329,20 @@ static inline void kasan_unpoison(const void *address, size_t size)
>  			round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
>  }
>  
> -static inline bool kasan_check_invalid_free(void *addr)
> +static inline bool kasan_byte_accessible(const void *addr)
>  {
>  	u8 ptr_tag = get_tag(addr);
> -	u8 mem_tag = hw_get_mem_tag(addr);
> +	u8 mem_tag = hw_get_mem_tag((void *)addr);
>  
> -	return (mem_tag == KASAN_TAG_INVALID) ||
> -		(ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
> +	return (mem_tag != KASAN_TAG_INVALID) &&
> +		(ptr_tag == KASAN_TAG_KERNEL || ptr_tag == mem_tag);
>  }
>  
>  #else /* CONFIG_KASAN_HW_TAGS */
>  
>  void kasan_poison(const void *address, size_t size, u8 value);
>  void kasan_unpoison(const void *address, size_t size);
> -bool kasan_check_invalid_free(void *addr);
> +bool kasan_byte_accessible(const void *addr);
>  
>  #endif /* CONFIG_KASAN_HW_TAGS */
>  
> diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> index cc271fceb5d5..94c2d33be333 100644
> --- a/mm/kasan/sw_tags.c
> +++ b/mm/kasan/sw_tags.c
> @@ -118,13 +118,13 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
>  	return true;
>  }
>  
> -bool kasan_check_invalid_free(void *addr)
> +bool kasan_byte_accessible(const void *addr)
>  {
>  	u8 tag = get_tag(addr);
>  	u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(kasan_reset_tag(addr)));
>  
> -	return (shadow_byte == KASAN_TAG_INVALID) ||
> -		(tag != KASAN_TAG_KERNEL && tag != shadow_byte);
> +	return (shadow_byte != KASAN_TAG_INVALID) &&
> +		(tag == KASAN_TAG_KERNEL || tag == shadow_byte);
>  }
>  
>  #define DEFINE_HWASAN_LOAD_STORE(size)					\
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index e981c80d216c..9c12cf4212ea 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -1157,19 +1157,21 @@ size_t ksize(const void *objp)
>  	size_t size;
>  
>  	/*
> -	 * We need to check that the pointed to object is valid, and only then
> -	 * unpoison the shadow memory below. We use __kasan_check_read(), to
> -	 * generate a more useful report at the time ksize() is called (rather
> -	 * than later where behaviour is undefined due to potential
> -	 * use-after-free or double-free).
> +	 * We need to first check that the pointer to the object is valid, and
> +	 * only then unpoison the memory. The report printed from ksize() is
> +	 * more useful, then when it's printed later when the behaviour could
> +	 * be undefined due to a potential use-after-free or double-free.
>  	 *
> -	 * If the pointed to memory is invalid we return 0, to avoid users of
> +	 * We use kasan_check_byte(), which is supported for the hardware
> +	 * tag-based KASAN mode, unlike kasan_check_read/write().
> +	 *
> +	 * If the pointed to memory is invalid, we return 0 to avoid users of
>  	 * ksize() writing to and potentially corrupting the memory region.
>  	 *
>  	 * We want to perform the check before __ksize(), to avoid potentially
>  	 * crashing in __ksize() due to accessing invalid metadata.
>  	 */
> -	if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
> +	if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
>  		return 0;
>  
>  	size = __ksize(objp);
> -- 
> 2.30.0.284.gd98b1dd5eaa7-goog
> 

Re: [PATCH v3 12/15] kasan: fix bug detection via ksize for HW_TAGS mode

[Alexander Potapenko]

On Fri, Jan 15, 2021 at 2:18 PM Marco Elver <elver@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> > The currently existing kasan_check_read/write() annotations are intended
> > to be used for kernel modules that have KASAN compiler instrumentation
> > disabled. Thus, they are only relevant for the software KASAN modes that
> > rely on compiler instrumentation.
> >
> > However there's another use case for these annotations: ksize() checks
> > that the object passed to it is indeed accessible before unpoisoning the
> > whole object. This is currently done via __kasan_check_read(), which is
> > compiled away for the hardware tag-based mode that doesn't rely on
> > compiler instrumentation. This leads to KASAN missing detecting some
> > memory corruptions.
> >
> > Provide another annotation called kasan_check_byte() that is available
> > for all KASAN modes. As the implementation rename and reuse
> > kasan_check_invalid_free(). Use this new annotation in ksize().
> > To avoid having ksize() as the top frame in the reported stack trace
> > pass _RET_IP_ to __kasan_check_byte().
> >
> > Also add a new ksize_uaf() test that checks that a use-after-free is
> > detected via ksize() itself, and via plain accesses that happen later.
> >
> > Link: https://linux-review.googlesource.com/id/Iaabf771881d0f9ce1b969f2a62938e99d3308ec5
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

[PATCH v3 13/15] kasan: add proper page allocator tests

[Andrey Konovalov]

The currently existing page allocator tests rely on kmalloc fallback
with large sizes that is only present for SLUB. Add proper tests that
use alloc/free_pages().

Link: https://linux-review.googlesource.com/id/Ia173d5a1b215fe6b2548d814ef0f4433cf983570
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 51 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 46 insertions(+), 5 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 566d894ba20b..ab22a653762e 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -147,6 +147,12 @@ static void kmalloc_node_oob_right(struct kunit *test)
 	kfree(ptr);
 }
 
+/*
+ * These kmalloc_pagealloc_* tests try allocating a memory chunk that doesn't
+ * fit into a slab cache and therefore is allocated via the page allocator
+ * fallback. Since this kind of fallback is only implemented for SLUB, these
+ * tests are limited to that allocator.
+ */
 static void kmalloc_pagealloc_oob_right(struct kunit *test)
 {
 	char *ptr;
@@ -154,14 +160,11 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test)
 
 	KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB);
 
-	/*
-	 * Allocate a chunk that does not fit into a SLUB cache to trigger
-	 * the page allocator fallback.
-	 */
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
 
 	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
+
 	kfree(ptr);
 }
 
@@ -174,8 +177,8 @@ static void kmalloc_pagealloc_uaf(struct kunit *test)
 
 	ptr = kmalloc(size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
-
 	kfree(ptr);
+
 	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);
 }
 
@@ -192,6 +195,42 @@ static void kmalloc_pagealloc_invalid_free(struct kunit *test)
 	KUNIT_EXPECT_KASAN_FAIL(test, kfree(ptr + 1));
 }
 
+static void pagealloc_oob_right(struct kunit *test)
+{
+	char *ptr;
+	struct page *pages;
+	size_t order = 4;
+	size_t size = (1UL << (PAGE_SHIFT + order));
+
+	/*
+	 * With generic KASAN page allocations have no redzones, thus
+	 * out-of-bounds detection is not guaranteed.
+	 * See https://bugzilla.kernel.org/show_bug.cgi?id=210503.
+	 */
+	KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
+
+	pages = alloc_pages(GFP_KERNEL, order);
+	ptr = page_address(pages);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0);
+	free_pages((unsigned long)ptr, order);
+}
+
+static void pagealloc_uaf(struct kunit *test)
+{
+	char *ptr;
+	struct page *pages;
+	size_t order = 4;
+
+	pages = alloc_pages(GFP_KERNEL, order);
+	ptr = page_address(pages);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+	free_pages((unsigned long)ptr, order);
+
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = 0);
+}
+
 static void kmalloc_large_oob_right(struct kunit *test)
 {
 	char *ptr;
@@ -903,6 +942,8 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kmalloc_pagealloc_oob_right),
 	KUNIT_CASE(kmalloc_pagealloc_uaf),
 	KUNIT_CASE(kmalloc_pagealloc_invalid_free),
+	KUNIT_CASE(pagealloc_oob_right),
+	KUNIT_CASE(pagealloc_uaf),
 	KUNIT_CASE(kmalloc_large_oob_right),
 	KUNIT_CASE(kmalloc_oob_krealloc_more),
 	KUNIT_CASE(kmalloc_oob_krealloc_less),
-- 
2.30.0.284.gd98b1dd5eaa7-goog

[PATCH v3 14/15] kasan: add a test for kmem_cache_alloc/free_bulk

[Andrey Konovalov]

Add a test for kmem_cache_alloc/free_bulk to make sure there are no
false-positives when these functions are used.

Link: https://linux-review.googlesource.com/id/I2a8bf797aecf81baeac61380c567308f319e263d
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 38 +++++++++++++++++++++++++++++++++-----
 1 file changed, 33 insertions(+), 5 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index ab22a653762e..a96376aa7293 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -479,10 +479,11 @@ static void kmem_cache_oob(struct kunit *test)
 {
 	char *p;
 	size_t size = 200;
-	struct kmem_cache *cache = kmem_cache_create("test_cache",
-						size, 0,
-						0, NULL);
+	struct kmem_cache *cache;
+
+	cache = kmem_cache_create("test_cache",	size, 0, 0, NULL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
+
 	p = kmem_cache_alloc(cache, GFP_KERNEL);
 	if (!p) {
 		kunit_err(test, "Allocation failed: %s\n", __func__);
@@ -491,11 +492,12 @@ static void kmem_cache_oob(struct kunit *test)
 	}
 
 	KUNIT_EXPECT_KASAN_FAIL(test, *p = p[size + OOB_TAG_OFF]);
+
 	kmem_cache_free(cache, p);
 	kmem_cache_destroy(cache);
 }
 
-static void memcg_accounted_kmem_cache(struct kunit *test)
+static void kmem_cache_accounted(struct kunit *test)
 {
 	int i;
 	char *p;
@@ -522,6 +524,31 @@ static void memcg_accounted_kmem_cache(struct kunit *test)
 	kmem_cache_destroy(cache);
 }
 
+static void kmem_cache_bulk(struct kunit *test)
+{
+	struct kmem_cache *cache;
+	size_t size = 200;
+	char *p[10];
+	bool ret;
+	int i;
+
+	cache = kmem_cache_create("test_cache",	size, 0, 0, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
+
+	ret = kmem_cache_alloc_bulk(cache, GFP_KERNEL, ARRAY_SIZE(p), (void **)&p);
+	if (!ret) {
+		kunit_err(test, "Allocation failed: %s\n", __func__);
+		kmem_cache_destroy(cache);
+		return;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(p); i++)
+		p[i][0] = p[i][size - 1] = 42;
+
+	kmem_cache_free_bulk(cache, ARRAY_SIZE(p), (void **)&p);
+	kmem_cache_destroy(cache);
+}
+
 static char global_array[10];
 
 static void kasan_global_oob(struct kunit *test)
@@ -961,7 +988,8 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kfree_via_page),
 	KUNIT_CASE(kfree_via_phys),
 	KUNIT_CASE(kmem_cache_oob),
-	KUNIT_CASE(memcg_accounted_kmem_cache),
+	KUNIT_CASE(kmem_cache_accounted),
+	KUNIT_CASE(kmem_cache_bulk),
 	KUNIT_CASE(kasan_global_oob),
 	KUNIT_CASE(kasan_stack_oob),
 	KUNIT_CASE(kasan_alloca_oob_left),
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 14/15] kasan: add a test for kmem_cache_alloc/free_bulk

[Marco Elver]

On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> Add a test for kmem_cache_alloc/free_bulk to make sure there are no
> false-positives when these functions are used.
> 
> Link: https://linux-review.googlesource.com/id/I2a8bf797aecf81baeac61380c567308f319e263d
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  lib/test_kasan.c | 38 +++++++++++++++++++++++++++++++++-----
>  1 file changed, 33 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index ab22a653762e..a96376aa7293 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -479,10 +479,11 @@ static void kmem_cache_oob(struct kunit *test)
>  {
>  	char *p;
>  	size_t size = 200;
> -	struct kmem_cache *cache = kmem_cache_create("test_cache",
> -						size, 0,
> -						0, NULL);
> +	struct kmem_cache *cache;
> +
> +	cache = kmem_cache_create("test_cache",	size, 0, 0, NULL);
>  	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
> +
>  	p = kmem_cache_alloc(cache, GFP_KERNEL);
>  	if (!p) {
>  		kunit_err(test, "Allocation failed: %s\n", __func__);
> @@ -491,11 +492,12 @@ static void kmem_cache_oob(struct kunit *test)
>  	}
>  
>  	KUNIT_EXPECT_KASAN_FAIL(test, *p = p[size + OOB_TAG_OFF]);
> +
>  	kmem_cache_free(cache, p);
>  	kmem_cache_destroy(cache);
>  }
>  
> -static void memcg_accounted_kmem_cache(struct kunit *test)
> +static void kmem_cache_accounted(struct kunit *test)
>  {
>  	int i;
>  	char *p;
> @@ -522,6 +524,31 @@ static void memcg_accounted_kmem_cache(struct kunit *test)
>  	kmem_cache_destroy(cache);
>  }
>  
> +static void kmem_cache_bulk(struct kunit *test)
> +{
> +	struct kmem_cache *cache;
> +	size_t size = 200;
> +	char *p[10];
> +	bool ret;
> +	int i;
> +
> +	cache = kmem_cache_create("test_cache",	size, 0, 0, NULL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache);
> +
> +	ret = kmem_cache_alloc_bulk(cache, GFP_KERNEL, ARRAY_SIZE(p), (void **)&p);
> +	if (!ret) {
> +		kunit_err(test, "Allocation failed: %s\n", __func__);
> +		kmem_cache_destroy(cache);
> +		return;
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(p); i++)
> +		p[i][0] = p[i][size - 1] = 42;
> +
> +	kmem_cache_free_bulk(cache, ARRAY_SIZE(p), (void **)&p);
> +	kmem_cache_destroy(cache);
> +}
> +
>  static char global_array[10];
>  
>  static void kasan_global_oob(struct kunit *test)
> @@ -961,7 +988,8 @@ static struct kunit_case kasan_kunit_test_cases[] = {
>  	KUNIT_CASE(kfree_via_page),
>  	KUNIT_CASE(kfree_via_phys),
>  	KUNIT_CASE(kmem_cache_oob),
> -	KUNIT_CASE(memcg_accounted_kmem_cache),
> +	KUNIT_CASE(kmem_cache_accounted),
> +	KUNIT_CASE(kmem_cache_bulk),
>  	KUNIT_CASE(kasan_global_oob),
>  	KUNIT_CASE(kasan_stack_oob),
>  	KUNIT_CASE(kasan_alloca_oob_left),
> -- 
> 2.30.0.284.gd98b1dd5eaa7-goog
> 

Re: [PATCH v3 14/15] kasan: add a test for kmem_cache_alloc/free_bulk

[Alexander Potapenko]

On Fri, Jan 15, 2021 at 2:16 PM Marco Elver <elver@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> > Add a test for kmem_cache_alloc/free_bulk to make sure there are no
> > false-positives when these functions are used.
> >
> > Link: https://linux-review.googlesource.com/id/I2a8bf797aecf81baeac61380c567308f319e263d
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>

(see a nit below)

> > +     cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
Looks like there's a tab between "test_cache" and size, please double-check.

Re: [PATCH v3 14/15] kasan: add a test for kmem_cache_alloc/free_bulk

[Andrey Konovalov]

On Fri, Jan 15, 2021 at 2:49 PM Alexander Potapenko <glider@google.com> wrote:
>
> On Fri, Jan 15, 2021 at 2:16 PM Marco Elver <elver@google.com> wrote:
> >
> > On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> > > Add a test for kmem_cache_alloc/free_bulk to make sure there are no
> > > false-positives when these functions are used.
> > >
> > > Link: https://linux-review.googlesource.com/id/I2a8bf797aecf81baeac61380c567308f319e263d
> > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> >
> > Reviewed-by: Marco Elver <elver@google.com>
> Reviewed-by: Alexander Potapenko <glider@google.com>
>
> (see a nit below)
>
> > > +     cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
> Looks like there's a tab between "test_cache" and size, please double-check.

Indeed, thanks for noticing! Will fix.

[PATCH v3 15/15] kasan: don't run tests when KASAN is not enabled

[Andrey Konovalov]

Don't run KASAN tests when it's disabled with kasan.mode=off to avoid
corrupting kernel memory.

Link: https://linux-review.googlesource.com/id/I6447af436a69a94bfc35477f6bf4e2122948355e
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/test_kasan.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index a96376aa7293..6238b56127f8 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -47,6 +47,11 @@ static bool multishot;
  */
 static int kasan_test_init(struct kunit *test)
 {
+	if (!kasan_enabled()) {
+		kunit_err(test, "can't run KASAN tests with KASAN disabled");
+		return -1;
+	}
+
 	multishot = kasan_save_enable_multi_shot();
 	hw_set_tagging_report_once(false);
 	return 0;
-- 
2.30.0.284.gd98b1dd5eaa7-goog

Re: [PATCH v3 15/15] kasan: don't run tests when KASAN is not enabled

[Marco Elver]

On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> Don't run KASAN tests when it's disabled with kasan.mode=off to avoid
> corrupting kernel memory.
> 
> Link: https://linux-review.googlesource.com/id/I6447af436a69a94bfc35477f6bf4e2122948355e
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Marco Elver <elver@google.com>

> ---
>  lib/test_kasan.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index a96376aa7293..6238b56127f8 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -47,6 +47,11 @@ static bool multishot;
>   */
>  static int kasan_test_init(struct kunit *test)
>  {
> +	if (!kasan_enabled()) {
> +		kunit_err(test, "can't run KASAN tests with KASAN disabled");
> +		return -1;
> +	}
> +
>  	multishot = kasan_save_enable_multi_shot();
>  	hw_set_tagging_report_once(false);
>  	return 0;
> -- 
> 2.30.0.284.gd98b1dd5eaa7-goog
> 

Re: [PATCH v3 15/15] kasan: don't run tests when KASAN is not enabled

[Alexander Potapenko]

On Fri, Jan 15, 2021 at 2:13 PM Marco Elver <elver@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 08:36PM +0100, Andrey Konovalov wrote:
> > Don't run KASAN tests when it's disabled with kasan.mode=off to avoid
> > corrupting kernel memory.
> >
> > Link: https://linux-review.googlesource.com/id/I6447af436a69a94bfc35477f6bf4e2122948355e
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>