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Commit ee3ce779 authored by Dmitry Vyukov's avatar Dmitry Vyukov Committed by Linus Torvalds
Browse files

kasan: don't use __builtin_return_address(1) 

__builtin_return_address(1) is unreliable without frame pointers.
With defconfig on kmalloc_pagealloc_invalid_free test I am getting:

BUG: KASAN: double-free or invalid-free in           (null)

Pass caller PC from callers explicitly.

Link: http://lkml.kernel.org/r/9b01bc2d237a4df74ff8472a3bf6b7635908de01.1514378558.git.dvyukov@google.com


Signed-off-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 47adccce

include/linux/kasan.h

+5 −4
Original line number Diff line number Diff line
@@ -56,14 +56,14 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object); 
void kasan_init_slab_obj(struct kmem_cache *cache, const void *object);



void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags);

void kasan_kfree_large(void *ptr);

void kasan_kfree_large(void *ptr, unsigned long ip);

void kasan_poison_kfree(void *ptr);

void kasan_kmalloc(struct kmem_cache *s, const void *object, size_t size,

		  gfp_t flags);

void kasan_krealloc(const void *object, size_t new_size, gfp_t flags);



void kasan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags);

bool kasan_slab_free(struct kmem_cache *s, void *object);

bool kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip);



struct kasan_cache {

	int alloc_meta_offset;
@@ -108,7 +108,7 @@ static inline void kasan_init_slab_obj(struct kmem_cache *cache, 
				const void *object) {}



static inline void kasan_kmalloc_large(void *ptr, size_t size, gfp_t flags) {}

static inline void kasan_kfree_large(void *ptr) {}

static inline void kasan_kfree_large(void *ptr, unsigned long ip) {}

static inline void kasan_poison_kfree(void *ptr) {}

static inline void kasan_kmalloc(struct kmem_cache *s, const void *object,

				size_t size, gfp_t flags) {}
@@ -117,7 +117,8 @@ static inline void kasan_krealloc(const void *object, size_t new_size, 


static inline void kasan_slab_alloc(struct kmem_cache *s, void *object,

				   gfp_t flags) {}

static inline bool kasan_slab_free(struct kmem_cache *s, void *object)

static inline bool kasan_slab_free(struct kmem_cache *s, void *object,

				   unsigned long ip)

{

	return false;

}

mm/kasan/kasan.c

+4 −4
Original line number Diff line number Diff line
@@ -501,7 +501,7 @@ static void kasan_poison_slab_free(struct kmem_cache *cache, void *object) 
	kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);

}



bool kasan_slab_free(struct kmem_cache *cache, void *object)

bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)

{

	s8 shadow_byte;
@@ -511,7 +511,7 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object) 


	shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));

	if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {

		kasan_report_invalid_free(object, __builtin_return_address(1));

		kasan_report_invalid_free(object, ip);

		return true;

	}
@@ -601,10 +601,10 @@ void kasan_poison_kfree(void *ptr) 
		kasan_poison_slab_free(page->slab_cache, ptr);

}



void kasan_kfree_large(void *ptr)

void kasan_kfree_large(void *ptr, unsigned long ip)

{

	if (ptr != page_address(virt_to_head_page(ptr)))

		kasan_report_invalid_free(ptr, __builtin_return_address(1));

		kasan_report_invalid_free(ptr, ip);

	/* The object will be poisoned by page_alloc. */

}

mm/kasan/kasan.h

+1 −1
Original line number Diff line number Diff line
@@ -107,7 +107,7 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr) 


void kasan_report(unsigned long addr, size_t size,

		bool is_write, unsigned long ip);

void kasan_report_invalid_free(void *object, void *ip);

void kasan_report_invalid_free(void *object, unsigned long ip);



#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)

void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);

mm/kasan/report.c

+2 −2
Original line number Diff line number Diff line
@@ -326,12 +326,12 @@ static void print_shadow_for_address(const void *addr) 
	}

}



void kasan_report_invalid_free(void *object, void *ip)

void kasan_report_invalid_free(void *object, unsigned long ip)

{

	unsigned long flags;



	kasan_start_report(&flags);

	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", ip);

	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);

	pr_err("\n");

	print_address_description(object);

	pr_err("\n");

mm/slab.c

+3 −3
Original line number Diff line number Diff line
@@ -3478,11 +3478,11 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) 
 * Release an obj back to its cache. If the obj has a constructed state, it must

 * be in this state _before_ it is released.  Called with disabled ints.

 */

static inline void __cache_free(struct kmem_cache *cachep, void *objp,

static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,

					 unsigned long caller)

{

	/* Put the object into the quarantine, don't touch it for now. */

	if (kasan_slab_free(cachep, objp))

	if (kasan_slab_free(cachep, objp, _RET_IP_))

		return;



	___cache_free(cachep, objp, caller);