Commit 80a9201a authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Linus Torvalds

mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB

For KASAN builds:
 - switch SLUB allocator to using stackdepot instead of storing the
   allocation/deallocation stacks in the objects;
 - change the freelist hook so that parts of the freelist can be put
   into the quarantine.

[aryabinin@virtuozzo.com: fixes]
  Link: http://lkml.kernel.org/r/1468601423-28676-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1468347165-41906-3-git-send-email-glider@google.comSigned-off-by: 's avatarAlexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c146a2b9
......@@ -77,6 +77,7 @@ void kasan_free_shadow(const struct vm_struct *vm);
size_t ksize(const void *);
static inline void kasan_unpoison_slab(const void *ptr) { ksize(ptr); }
size_t kasan_metadata_size(struct kmem_cache *cache);
#else /* CONFIG_KASAN */
......@@ -121,6 +122,7 @@ static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
static inline void kasan_free_shadow(const struct vm_struct *vm) {}
static inline void kasan_unpoison_slab(const void *ptr) { }
static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
#endif /* CONFIG_KASAN */
......
......@@ -88,7 +88,8 @@ struct kmem_cache {
};
static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
void *x) {
void *x)
{
void *object = x - (x - page->s_mem) % cache->size;
void *last_object = page->s_mem + (cache->num - 1) * cache->size;
......
......@@ -104,6 +104,10 @@ struct kmem_cache {
unsigned int *random_seq;
#endif
#ifdef CONFIG_KASAN
struct kasan_cache kasan_info;
#endif
struct kmem_cache_node *node[MAX_NUMNODES];
};
......
......@@ -5,9 +5,9 @@ if HAVE_ARCH_KASAN
config KASAN
bool "KASan: runtime memory debugger"
depends on SLUB_DEBUG || (SLAB && !DEBUG_SLAB)
depends on SLUB || (SLAB && !DEBUG_SLAB)
select CONSTRUCTORS
select STACKDEPOT if SLAB
select STACKDEPOT
help
Enables kernel address sanitizer - runtime memory debugger,
designed to find out-of-bounds accesses and use-after-free bugs.
......
......@@ -7,5 +7,4 @@ CFLAGS_REMOVE_kasan.o = -pg
# see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
obj-y := kasan.o report.o kasan_init.o
obj-$(CONFIG_SLAB) += quarantine.o
obj-y := kasan.o report.o kasan_init.o quarantine.o
......@@ -351,7 +351,6 @@ void kasan_free_pages(struct page *page, unsigned int order)
KASAN_FREE_PAGE);
}
#ifdef CONFIG_SLAB
/*
* Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
* For larger allocations larger redzones are used.
......@@ -373,16 +372,8 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
unsigned long *flags)
{
int redzone_adjust;
/* Make sure the adjusted size is still less than
* KMALLOC_MAX_CACHE_SIZE.
* TODO: this check is only useful for SLAB, but not SLUB. We'll need
* to skip it for SLUB when it starts using kasan_cache_create().
*/
if (*size > KMALLOC_MAX_CACHE_SIZE -
sizeof(struct kasan_alloc_meta) -
sizeof(struct kasan_free_meta))
return;
*flags |= SLAB_KASAN;
int orig_size = *size;
/* Add alloc meta. */
cache->kasan_info.alloc_meta_offset = *size;
*size += sizeof(struct kasan_alloc_meta);
......@@ -395,14 +386,26 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
}
redzone_adjust = optimal_redzone(cache->object_size) -
(*size - cache->object_size);
if (redzone_adjust > 0)
*size += redzone_adjust;
*size = min(KMALLOC_MAX_CACHE_SIZE,
max(*size,
cache->object_size +
optimal_redzone(cache->object_size)));
*size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
optimal_redzone(cache->object_size)));
/*
* If the metadata doesn't fit, don't enable KASAN at all.
*/
if (*size <= cache->kasan_info.alloc_meta_offset ||
*size <= cache->kasan_info.free_meta_offset) {
cache->kasan_info.alloc_meta_offset = 0;
cache->kasan_info.free_meta_offset = 0;
*size = orig_size;
return;
}
*flags |= SLAB_KASAN;
}
#endif
void kasan_cache_shrink(struct kmem_cache *cache)
{
......@@ -414,6 +417,14 @@ void kasan_cache_destroy(struct kmem_cache *cache)
quarantine_remove_cache(cache);
}
size_t kasan_metadata_size(struct kmem_cache *cache)
{
return (cache->kasan_info.alloc_meta_offset ?
sizeof(struct kasan_alloc_meta) : 0) +
(cache->kasan_info.free_meta_offset ?
sizeof(struct kasan_free_meta) : 0);
}
void kasan_poison_slab(struct page *page)
{
kasan_poison_shadow(page_address(page),
......@@ -431,16 +442,13 @@ void kasan_poison_object_data(struct kmem_cache *cache, void *object)
kasan_poison_shadow(object,
round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
KASAN_KMALLOC_REDZONE);
#ifdef CONFIG_SLAB
if (cache->flags & SLAB_KASAN) {
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
alloc_info->state = KASAN_STATE_INIT;
}
#endif
}
#ifdef CONFIG_SLAB
static inline int in_irqentry_text(unsigned long ptr)
{
return (ptr >= (unsigned long)&__irqentry_text_start &&
......@@ -501,7 +509,6 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
return (void *)object + cache->kasan_info.free_meta_offset;
}
#endif
void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
{
......@@ -522,16 +529,16 @@ static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
bool kasan_slab_free(struct kmem_cache *cache, void *object)
{
#ifdef CONFIG_SLAB
/* RCU slabs could be legally used after free within the RCU period */
if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
return false;
if (likely(cache->flags & SLAB_KASAN)) {
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
struct kasan_free_meta *free_info =
get_free_info(cache, object);
struct kasan_alloc_meta *alloc_info;
struct kasan_free_meta *free_info;
alloc_info = get_alloc_info(cache, object);
free_info = get_free_info(cache, object);
switch (alloc_info->state) {
case KASAN_STATE_ALLOC:
......@@ -550,10 +557,6 @@ bool kasan_slab_free(struct kmem_cache *cache, void *object)
}
}
return false;
#else
kasan_poison_slab_free(cache, object);
return false;
#endif
}
void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
......@@ -576,7 +579,6 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
kasan_unpoison_shadow(object, size);
kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
KASAN_KMALLOC_REDZONE);
#ifdef CONFIG_SLAB
if (cache->flags & SLAB_KASAN) {
struct kasan_alloc_meta *alloc_info =
get_alloc_info(cache, object);
......@@ -585,7 +587,6 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
alloc_info->alloc_size = size;
set_track(&alloc_info->track, flags);
}
#endif
}
EXPORT_SYMBOL(kasan_kmalloc);
......
......@@ -95,7 +95,6 @@ struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
const void *object);
static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
{
return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
......@@ -110,7 +109,7 @@ static inline bool kasan_report_enabled(void)
void kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
#ifdef CONFIG_SLAB
#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
void quarantine_reduce(void);
void quarantine_remove_cache(struct kmem_cache *cache);
......
......@@ -116,7 +116,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
#ifdef CONFIG_SLAB
static void print_track(struct kasan_track *track)
{
pr_err("PID = %u\n", track->pid);
......@@ -130,8 +129,8 @@ static void print_track(struct kasan_track *track)
}
}
static void object_err(struct kmem_cache *cache, struct page *page,
void *object, char *unused_reason)
static void kasan_object_err(struct kmem_cache *cache, struct page *page,
void *object, char *unused_reason)
{
struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
struct kasan_free_meta *free_info;
......@@ -162,7 +161,6 @@ static void object_err(struct kmem_cache *cache, struct page *page,
break;
}
}
#endif
static void print_address_description(struct kasan_access_info *info)
{
......@@ -177,7 +175,7 @@ static void print_address_description(struct kasan_access_info *info)
struct kmem_cache *cache = page->slab_cache;
object = nearest_obj(cache, page,
(void *)info->access_addr);
object_err(cache, page, object,
kasan_object_err(cache, page, object,
"kasan: bad access detected");
return;
}
......
......@@ -369,6 +369,8 @@ static inline size_t slab_ksize(const struct kmem_cache *s)
if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
return s->object_size;
# endif
if (s->flags & SLAB_KASAN)
return s->object_size;
/*
* If we have the need to store the freelist pointer
* back there or track user information then we can
......
......@@ -454,8 +454,6 @@ static inline void *restore_red_left(struct kmem_cache *s, void *p)
*/
#if defined(CONFIG_SLUB_DEBUG_ON)
static int slub_debug = DEBUG_DEFAULT_FLAGS;
#elif defined(CONFIG_KASAN)
static int slub_debug = SLAB_STORE_USER;
#else
static int slub_debug;
#endif
......@@ -660,6 +658,8 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
if (s->flags & SLAB_STORE_USER)
off += 2 * sizeof(struct track);
off += kasan_metadata_size(s);
if (off != size_from_object(s))
/* Beginning of the filler is the free pointer */
print_section("Padding ", p + off, size_from_object(s) - off);
......@@ -787,6 +787,8 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
/* We also have user information there */
off += 2 * sizeof(struct track);
off += kasan_metadata_size(s);
if (size_from_object(s) == off)
return 1;
......@@ -1322,8 +1324,10 @@ static inline void kfree_hook(const void *x)
kasan_kfree_large(x);
}
static inline void slab_free_hook(struct kmem_cache *s, void *x)
static inline void *slab_free_hook(struct kmem_cache *s, void *x)
{
void *freeptr;
kmemleak_free_recursive(x, s->flags);
/*
......@@ -1344,7 +1348,13 @@ static inline void slab_free_hook(struct kmem_cache *s, void *x)
if (!(s->flags & SLAB_DEBUG_OBJECTS))
debug_check_no_obj_freed(x, s->object_size);
freeptr = get_freepointer(s, x);
/*
* kasan_slab_free() may put x into memory quarantine, delaying its
* reuse. In this case the object's freelist pointer is changed.
*/
kasan_slab_free(s, x);
return freeptr;
}
static inline void slab_free_freelist_hook(struct kmem_cache *s,
......@@ -1362,11 +1372,11 @@ static inline void slab_free_freelist_hook(struct kmem_cache *s,
void *object = head;
void *tail_obj = tail ? : head;
void *freeptr;
do {
slab_free_hook(s, object);
} while ((object != tail_obj) &&
(object = get_freepointer(s, object)));
freeptr = slab_free_hook(s, object);
} while ((object != tail_obj) && (object = freeptr));
#endif
}
......@@ -2878,16 +2888,13 @@ slab_empty:
* same page) possible by specifying head and tail ptr, plus objects
* count (cnt). Bulk free indicated by tail pointer being set.
*/
static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
void *head, void *tail, int cnt,
unsigned long addr)
static __always_inline void do_slab_free(struct kmem_cache *s,
struct page *page, void *head, void *tail,
int cnt, unsigned long addr)
{
void *tail_obj = tail ? : head;
struct kmem_cache_cpu *c;
unsigned long tid;
slab_free_freelist_hook(s, head, tail);
redo:
/*
* Determine the currently cpus per cpu slab.
......@@ -2921,6 +2928,27 @@ redo:
}
static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
void *head, void *tail, int cnt,
unsigned long addr)
{
slab_free_freelist_hook(s, head, tail);
/*
* slab_free_freelist_hook() could have put the items into quarantine.
* If so, no need to free them.
*/
if (s->flags & SLAB_KASAN && !(s->flags & SLAB_DESTROY_BY_RCU))
return;
do_slab_free(s, page, head, tail, cnt, addr);
}
#ifdef CONFIG_KASAN
void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
{
do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
}
#endif
void kmem_cache_free(struct kmem_cache *s, void *x)
{
s = cache_from_obj(s, x);
......@@ -3363,7 +3391,7 @@ static void set_min_partial(struct kmem_cache *s, unsigned long min)
static int calculate_sizes(struct kmem_cache *s, int forced_order)
{
unsigned long flags = s->flags;
unsigned long size = s->object_size;
size_t size = s->object_size;
int order;
/*
......@@ -3422,7 +3450,10 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
* the object.
*/
size += 2 * sizeof(struct track);
#endif
kasan_cache_create(s, &size, &s->flags);
#ifdef CONFIG_SLUB_DEBUG
if (flags & SLAB_RED_ZONE) {
/*
* Add some empty padding so that we can catch
......
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