Move free track from slub alloc meta-data to slub free meta-data in order to make struct kasan_free_meta size is 16 bytes. It is a good size because it is the minimal redzone size and a good number of alignment.
For free track in generic KASAN, we do the modification in struct kasan_alloc_meta and kasan_free_meta: - remove free track from kasan_alloc_meta. - add free track into kasan_free_meta. [1]https://bugzilla.kernel.org/show_bug.cgi?id=198437 Signed-off-by: Walter Wu <walter-zh...@mediatek.com> Suggested-by: Dmitry Vyukov <dvyu...@google.com> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> Cc: Dmitry Vyukov <dvyu...@google.com> Cc: Alexander Potapenko <gli...@google.com> --- mm/kasan/common.c | 33 ++++++++++----------------------- mm/kasan/generic.c | 18 ++++++++++++++++++ mm/kasan/kasan.h | 7 +++++++ mm/kasan/report.c | 20 -------------------- mm/kasan/tags.c | 37 +++++++++++++++++++++++++++++++++++++ 5 files changed, 72 insertions(+), 43 deletions(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 8bc618289bb1..6500bc2bb70c 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -51,7 +51,7 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags) return stack_depot_save(entries, nr_entries, flags); } -static inline void set_track(struct kasan_track *track, gfp_t flags) +void kasan_set_track(struct kasan_track *track, gfp_t flags) { track->pid = current->pid; track->stack = kasan_save_stack(flags); @@ -249,9 +249,7 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, *size += sizeof(struct kasan_alloc_meta); /* Add free meta. */ - if (IS_ENABLED(CONFIG_KASAN_GENERIC) && - (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || - cache->object_size < sizeof(struct kasan_free_meta))) { + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) { cache->kasan_info.free_meta_offset = *size; *size += sizeof(struct kasan_free_meta); } @@ -299,24 +297,6 @@ struct kasan_free_meta *get_free_info(struct kmem_cache *cache, return (void *)object + cache->kasan_info.free_meta_offset; } - -static void kasan_set_free_info(struct kmem_cache *cache, - void *object, u8 tag) -{ - struct kasan_alloc_meta *alloc_meta; - u8 idx = 0; - - alloc_meta = get_alloc_info(cache, object); - -#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY - idx = alloc_meta->free_track_idx; - alloc_meta->free_pointer_tag[idx] = tag; - alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS; -#endif - - set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); -} - void kasan_poison_slab(struct page *page) { unsigned long i; @@ -396,6 +376,13 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, alloc_info = get_alloc_info(cache, object); __memset(alloc_info, 0, sizeof(*alloc_info)); + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) { + struct kasan_free_meta *free_info; + + free_info = get_free_info(cache, object); + __memset(free_info, 0, sizeof(*free_info)); + } + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) object = set_tag(object, assign_tag(cache, object, true, false)); @@ -492,7 +479,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, KASAN_KMALLOC_REDZONE); if (cache->flags & SLAB_KASAN) - set_track(&get_alloc_info(cache, object)->alloc_track, flags); + kasan_set_track(&get_alloc_info(cache, object)->alloc_track, flags); return set_tag(object, tag); } diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 78d8e0a75a8a..988bc095b738 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -345,3 +345,21 @@ void kasan_record_aux_stack(void *addr) alloc_info->rcu_stack[1] = alloc_info->rcu_stack[0]; alloc_info->rcu_stack[0] = kasan_save_stack(GFP_NOWAIT); } + +void kasan_set_free_info(struct kmem_cache *cache, + void *object, u8 tag) +{ + struct kasan_free_meta *free_meta; + + free_meta = get_free_info(cache, object); + kasan_set_track(&free_meta->free_track, GFP_NOWAIT); +} + +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, + void *object, u8 tag) +{ + struct kasan_free_meta *free_meta; + + free_meta = get_free_info(cache, object); + return &free_meta->free_track; +} diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 870c5dd07756..87ee3626b8b0 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -127,6 +127,9 @@ struct kasan_free_meta { * Otherwise it might be used for the allocator freelist. */ struct qlist_node quarantine_link; +#ifdef CONFIG_KASAN_GENERIC + struct kasan_track free_track; +#endif }; struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, @@ -168,6 +171,10 @@ void kasan_report_invalid_free(void *object, unsigned long ip); struct page *kasan_addr_to_page(const void *addr); depot_stack_handle_t kasan_save_stack(gfp_t flags); +void kasan_set_track(struct kasan_track *track, gfp_t flags); +void kasan_set_free_info(struct kmem_cache *cache, void *object, u8 tag); +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, + void *object, u8 tag); #if defined(CONFIG_KASAN_GENERIC) && \ (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 5ee66cf7e27c..7e9f9f6d5e85 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -159,26 +159,6 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, (void *)(object_addr + cache->object_size)); } -static struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, - void *object, u8 tag) -{ - struct kasan_alloc_meta *alloc_meta; - int i = 0; - - alloc_meta = get_alloc_info(cache, object); - -#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY - for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { - if (alloc_meta->free_pointer_tag[i] == tag) - break; - } - if (i == KASAN_NR_FREE_STACKS) - i = alloc_meta->free_track_idx; -#endif - - return &alloc_meta->free_track[i]; -} - #ifdef CONFIG_KASAN_GENERIC static void print_stack(depot_stack_handle_t stack) { diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index 25b7734e7013..201dee5d6ae0 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -162,3 +162,40 @@ void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size) kasan_poison_shadow((void *)addr, size, tag); } EXPORT_SYMBOL(__hwasan_tag_memory); + +void kasan_set_free_info(struct kmem_cache *cache, + void *object, u8 tag) +{ + struct kasan_alloc_meta *alloc_meta; + u8 idx = 0; + + alloc_meta = get_alloc_info(cache, object); + +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY + idx = alloc_meta->free_track_idx; + alloc_meta->free_pointer_tag[idx] = tag; + alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS; +#endif + + kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); +} + +struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, + void *object, u8 tag) +{ + struct kasan_alloc_meta *alloc_meta; + int i = 0; + + alloc_meta = get_alloc_info(cache, object); + +#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY + for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { + if (alloc_meta->free_pointer_tag[i] == tag) + break; + } + if (i == KASAN_NR_FREE_STACKS) + i = alloc_meta->free_track_idx; +#endif + + return &alloc_meta->free_track[i]; +} -- 2.18.0
