diff options
author | Alexander Potapenko <glider@google.com> | 2016-03-26 00:21:59 +0300 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-26 02:37:42 +0300 |
commit | 7ed2f9e663854db313f177a511145630e398b402 (patch) | |
tree | f9dfba81a688864a4d78689470f624b0a482f545 /mm/kasan | |
parent | e6e8379c876de16c6b78f83b15d5ac32c79cb440 (diff) | |
download | linux-7ed2f9e663854db313f177a511145630e398b402.tar.xz |
mm, kasan: SLAB support
Add KASAN hooks to SLAB allocator.
This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
-rw-r--r-- | mm/kasan/kasan.c | 102 | ||||
-rw-r--r-- | mm/kasan/kasan.h | 34 | ||||
-rw-r--r-- | mm/kasan/report.c | 54 |
3 files changed, 179 insertions, 11 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 1ad20ade8c91..7c82509ef169 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -334,6 +334,59 @@ 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. + */ +static size_t optimal_redzone(size_t object_size) +{ + int rz = + object_size <= 64 - 16 ? 16 : + object_size <= 128 - 32 ? 32 : + object_size <= 512 - 64 ? 64 : + object_size <= 4096 - 128 ? 128 : + object_size <= (1 << 14) - 256 ? 256 : + object_size <= (1 << 15) - 512 ? 512 : + object_size <= (1 << 16) - 1024 ? 1024 : 2048; + return rz; +} + +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; + /* Add alloc meta. */ + cache->kasan_info.alloc_meta_offset = *size; + *size += sizeof(struct kasan_alloc_meta); + + /* Add free meta. */ + if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor || + cache->object_size < sizeof(struct kasan_free_meta)) { + cache->kasan_info.free_meta_offset = *size; + *size += sizeof(struct kasan_free_meta); + } + 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))); +} +#endif + void kasan_poison_slab(struct page *page) { kasan_poison_shadow(page_address(page), @@ -351,8 +404,36 @@ 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 +} + +static inline void set_track(struct kasan_track *track) +{ + track->cpu = raw_smp_processor_id(); + track->pid = current->pid; + track->when = jiffies; } +#ifdef CONFIG_SLAB +struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, + const void *object) +{ + return (void *)object + cache->kasan_info.alloc_meta_offset; +} + +struct kasan_free_meta *get_free_info(struct kmem_cache *cache, + const void *object) +{ + return (void *)object + cache->kasan_info.free_meta_offset; +} +#endif + void kasan_slab_alloc(struct kmem_cache *cache, void *object) { kasan_kmalloc(cache, object, cache->object_size); @@ -367,6 +448,17 @@ void kasan_slab_free(struct kmem_cache *cache, void *object) if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU)) return; +#ifdef CONFIG_SLAB + if (cache->flags & SLAB_KASAN) { + struct kasan_free_meta *free_info = + get_free_info(cache, object); + struct kasan_alloc_meta *alloc_info = + get_alloc_info(cache, object); + alloc_info->state = KASAN_STATE_FREE; + set_track(&free_info->track); + } +#endif + kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); } @@ -386,6 +478,16 @@ 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); + + alloc_info->state = KASAN_STATE_ALLOC; + alloc_info->alloc_size = size; + set_track(&alloc_info->track); + } +#endif } EXPORT_SYMBOL(kasan_kmalloc); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 4f6c62e5c21e..7b9e4ab9b66b 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -54,6 +54,40 @@ struct kasan_global { #endif }; +/** + * Structures to keep alloc and free tracks * + */ + +enum kasan_state { + KASAN_STATE_INIT, + KASAN_STATE_ALLOC, + KASAN_STATE_FREE +}; + +struct kasan_track { + u64 cpu : 6; /* for NR_CPUS = 64 */ + u64 pid : 16; /* 65536 processes */ + u64 when : 42; /* ~140 years */ +}; + +struct kasan_alloc_meta { + u32 state : 2; /* enum kasan_state */ + u32 alloc_size : 30; + struct kasan_track track; +}; + +struct kasan_free_meta { + /* Allocator freelist pointer, unused by KASAN. */ + void **freelist; + struct kasan_track track; +}; + +struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, + const void *object); +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) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 745aa8f36028..3e3385cc97ac 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -115,6 +115,46 @@ 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, CPU = %u, timestamp = %lu\n", track->pid, + track->cpu, (unsigned long)track->when); +} + +static void 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; + + dump_stack(); + pr_err("Object at %p, in cache %s\n", object, cache->name); + if (!(cache->flags & SLAB_KASAN)) + return; + switch (alloc_info->state) { + case KASAN_STATE_INIT: + pr_err("Object not allocated yet\n"); + break; + case KASAN_STATE_ALLOC: + pr_err("Object allocated with size %u bytes.\n", + alloc_info->alloc_size); + pr_err("Allocation:\n"); + print_track(&alloc_info->track); + break; + case KASAN_STATE_FREE: + pr_err("Object freed, allocated with size %u bytes\n", + alloc_info->alloc_size); + free_info = get_free_info(cache, object); + pr_err("Allocation:\n"); + print_track(&alloc_info->track); + pr_err("Deallocation:\n"); + print_track(&free_info->track); + break; + } +} +#endif + static void print_address_description(struct kasan_access_info *info) { const void *addr = info->access_addr; @@ -126,17 +166,10 @@ static void print_address_description(struct kasan_access_info *info) if (PageSlab(page)) { void *object; struct kmem_cache *cache = page->slab_cache; - void *last_object; - - object = virt_to_obj(cache, page_address(page), addr); - last_object = page_address(page) + - page->objects * cache->size; - - if (unlikely(object > last_object)) - object = last_object; /* we hit into padding */ - + object = nearest_obj(cache, page, + (void *)info->access_addr); object_err(cache, page, object, - "kasan: bad access detected"); + "kasan: bad access detected"); return; } dump_page(page, "kasan: bad access detected"); @@ -146,7 +179,6 @@ static void print_address_description(struct kasan_access_info *info) if (!init_task_stack_addr(addr)) pr_err("Address belongs to variable %pS\n", addr); } - dump_stack(); } |