diff options
| -rw-r--r-- | mm/kasan/common.c | 8 | ||||
| -rw-r--r-- | mm/kasan/generic.c | 68 | ||||
| -rw-r--r-- | mm/kasan/kasan.h | 10 | ||||
| -rw-r--r-- | mm/kasan/quarantine.c | 5 |
4 files changed, 14 insertions, 77 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 610efae91220..6ca63e8dda74 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -65,8 +65,7 @@ void kasan_save_track(struct kasan_track *track, gfp_t flags) { depot_stack_handle_t stack; - stack = kasan_save_stack(flags, - STACK_DEPOT_FLAG_CAN_ALLOC | STACK_DEPOT_FLAG_GET); + stack = kasan_save_stack(flags, STACK_DEPOT_FLAG_CAN_ALLOC); kasan_set_track(track, stack); } @@ -266,10 +265,9 @@ bool __kasan_slab_free(struct kmem_cache *cache, void *object, return true; /* - * If the object is not put into quarantine, it will likely be quickly - * reallocated. Thus, release its metadata now. + * Note: Keep per-object metadata to allow KASAN print stack traces for + * use-after-free-before-realloc bugs. */ - kasan_release_object_meta(cache, object); /* Let slab put the object onto the freelist. */ return false; diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 032bf3e98c24..1900f8576034 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -485,16 +485,6 @@ void kasan_init_object_meta(struct kmem_cache *cache, const void *object) if (alloc_meta) { /* Zero out alloc meta to mark it as invalid. */ __memset(alloc_meta, 0, sizeof(*alloc_meta)); - - /* - * Prepare the lock for saving auxiliary stack traces. - * Temporarily disable KASAN bug reporting to allow instrumented - * raw_spin_lock_init to access aux_lock, which resides inside - * of a redzone. - */ - kasan_disable_current(); - raw_spin_lock_init(&alloc_meta->aux_lock); - kasan_enable_current(); } /* @@ -506,18 +496,8 @@ void kasan_init_object_meta(struct kmem_cache *cache, const void *object) static void release_alloc_meta(struct kasan_alloc_meta *meta) { - /* Evict the stack traces from stack depot. */ - stack_depot_put(meta->alloc_track.stack); - stack_depot_put(meta->aux_stack[0]); - stack_depot_put(meta->aux_stack[1]); - - /* - * Zero out alloc meta to mark it as invalid but keep aux_lock - * initialized to avoid having to reinitialize it when another object - * is allocated in the same slot. - */ - __memset(&meta->alloc_track, 0, sizeof(meta->alloc_track)); - __memset(meta->aux_stack, 0, sizeof(meta->aux_stack)); + /* Zero out alloc meta to mark it as invalid. */ + __memset(meta, 0, sizeof(*meta)); } static void release_free_meta(const void *object, struct kasan_free_meta *meta) @@ -529,27 +509,10 @@ static void release_free_meta(const void *object, struct kasan_free_meta *meta) if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREE_META) return; - /* Evict the stack trace from the stack depot. */ - stack_depot_put(meta->free_track.stack); - /* Mark free meta as invalid. */ *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; } -void kasan_release_object_meta(struct kmem_cache *cache, const void *object) -{ - struct kasan_alloc_meta *alloc_meta; - struct kasan_free_meta *free_meta; - - alloc_meta = kasan_get_alloc_meta(cache, object); - if (alloc_meta) - release_alloc_meta(alloc_meta); - - free_meta = kasan_get_free_meta(cache, object); - if (free_meta) - release_free_meta(object, free_meta); -} - size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object) { struct kasan_cache *info = &cache->kasan_info; @@ -574,8 +537,6 @@ static void __kasan_record_aux_stack(void *addr, depot_flags_t depot_flags) struct kmem_cache *cache; struct kasan_alloc_meta *alloc_meta; void *object; - depot_stack_handle_t new_handle, old_handle; - unsigned long flags; if (is_kfence_address(addr) || !slab) return; @@ -586,33 +547,18 @@ static void __kasan_record_aux_stack(void *addr, depot_flags_t depot_flags) if (!alloc_meta) return; - new_handle = kasan_save_stack(0, depot_flags); - - /* - * Temporarily disable KASAN bug reporting to allow instrumented - * spinlock functions to access aux_lock, which resides inside of a - * redzone. - */ - kasan_disable_current(); - raw_spin_lock_irqsave(&alloc_meta->aux_lock, flags); - old_handle = alloc_meta->aux_stack[1]; alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0]; - alloc_meta->aux_stack[0] = new_handle; - raw_spin_unlock_irqrestore(&alloc_meta->aux_lock, flags); - kasan_enable_current(); - - stack_depot_put(old_handle); + alloc_meta->aux_stack[0] = kasan_save_stack(0, depot_flags); } void kasan_record_aux_stack(void *addr) { - return __kasan_record_aux_stack(addr, - STACK_DEPOT_FLAG_CAN_ALLOC | STACK_DEPOT_FLAG_GET); + return __kasan_record_aux_stack(addr, STACK_DEPOT_FLAG_CAN_ALLOC); } void kasan_record_aux_stack_noalloc(void *addr) { - return __kasan_record_aux_stack(addr, STACK_DEPOT_FLAG_GET); + return __kasan_record_aux_stack(addr, 0); } void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) @@ -623,7 +569,7 @@ void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) if (!alloc_meta) return; - /* Evict previous stack traces (might exist for krealloc or mempool). */ + /* Invalidate previous stack traces (might exist for krealloc or mempool). */ release_alloc_meta(alloc_meta); kasan_save_track(&alloc_meta->alloc_track, flags); @@ -637,7 +583,7 @@ void kasan_save_free_info(struct kmem_cache *cache, void *object) if (!free_meta) return; - /* Evict previous stack trace (might exist for mempool). */ + /* Invalidate previous stack trace (might exist for mempool). */ release_free_meta(object, free_meta); kasan_save_track(&free_meta->free_track, 0); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index d0f172f2b978..fb2b9ac0659a 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -6,7 +6,6 @@ #include <linux/kasan.h> #include <linux/kasan-tags.h> #include <linux/kfence.h> -#include <linux/spinlock.h> #include <linux/stackdepot.h> #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) @@ -265,13 +264,6 @@ struct kasan_global { struct kasan_alloc_meta { struct kasan_track alloc_track; /* Free track is stored in kasan_free_meta. */ - /* - * aux_lock protects aux_stack from accesses from concurrent - * kasan_record_aux_stack calls. It is a raw spinlock to avoid sleeping - * on RT kernels, as kasan_record_aux_stack_noalloc can be called from - * non-sleepable contexts. - */ - raw_spinlock_t aux_lock; depot_stack_handle_t aux_stack[2]; }; @@ -398,10 +390,8 @@ struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, const void *object); void kasan_init_object_meta(struct kmem_cache *cache, const void *object); -void kasan_release_object_meta(struct kmem_cache *cache, const void *object); #else static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *object) { } -static inline void kasan_release_object_meta(struct kmem_cache *cache, const void *object) { } #endif depot_stack_handle_t kasan_save_stack(gfp_t flags, depot_flags_t depot_flags); diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 3ba02efb952a..6958aa713c67 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -145,7 +145,10 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) void *object = qlink_to_object(qlink, cache); struct kasan_free_meta *free_meta = kasan_get_free_meta(cache, object); - kasan_release_object_meta(cache, object); + /* + * Note: Keep per-object metadata to allow KASAN print stack traces for + * use-after-free-before-realloc bugs. + */ /* * If init_on_free is enabled and KASAN's free metadata is stored in |