diff options
Diffstat (limited to 'mm/kasan/common.c')
| -rw-r--r-- | mm/kasan/common.c | 291 |
1 files changed, 194 insertions, 97 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 256930da578a..6ca63e8dda74 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -20,8 +20,10 @@ #include <linux/module.h> #include <linux/printk.h> #include <linux/sched.h> +#include <linux/sched/clock.h> #include <linux/sched/task_stack.h> #include <linux/slab.h> +#include <linux/stackdepot.h> #include <linux/stacktrace.h> #include <linux/string.h> #include <linux/types.h> @@ -37,19 +39,34 @@ struct slab *kasan_addr_to_slab(const void *addr) return NULL; } -depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc) +depot_stack_handle_t kasan_save_stack(gfp_t flags, depot_flags_t depot_flags) { unsigned long entries[KASAN_STACK_DEPTH]; unsigned int nr_entries; nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); - return __stack_depot_save(entries, nr_entries, flags, can_alloc); + return stack_depot_save_flags(entries, nr_entries, flags, depot_flags); } -void kasan_set_track(struct kasan_track *track, gfp_t flags) +void kasan_set_track(struct kasan_track *track, depot_stack_handle_t stack) { +#ifdef CONFIG_KASAN_EXTRA_INFO + u32 cpu = raw_smp_processor_id(); + u64 ts_nsec = local_clock(); + + track->cpu = cpu; + track->timestamp = ts_nsec >> 3; +#endif /* CONFIG_KASAN_EXTRA_INFO */ track->pid = current->pid; - track->stack = kasan_save_stack(flags, true); + track->stack = stack; +} + +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); + kasan_set_track(track, stack); } #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) @@ -69,6 +86,9 @@ EXPORT_SYMBOL(kasan_disable_current); void __kasan_unpoison_range(const void *address, size_t size) { + if (is_kfence_address(address)) + return; + kasan_unpoison(address, size, false); } @@ -133,12 +153,12 @@ void __kasan_poison_slab(struct slab *slab) KASAN_SLAB_REDZONE, false); } -void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object) +void __kasan_unpoison_new_object(struct kmem_cache *cache, void *object) { kasan_unpoison(object, cache->object_size, false); } -void __kasan_poison_object_data(struct kmem_cache *cache, void *object) +void __kasan_poison_new_object(struct kmem_cache *cache, void *object) { kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE), KASAN_SLAB_REDZONE, false); @@ -153,10 +173,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object) * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be * accessed after being freed. We preassign tags for objects in these * caches as well. - * 3. For SLAB allocator we can't preassign tags randomly since the freelist - * is stored as an array of indexes instead of a linked list. Assign tags - * based on objects indexes, so that objects that are next to each other - * get different tags. */ static inline u8 assign_tag(struct kmem_cache *cache, const void *object, bool init) @@ -171,17 +187,12 @@ static inline u8 assign_tag(struct kmem_cache *cache, if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU)) return init ? KASAN_TAG_KERNEL : kasan_random_tag(); - /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */ -#ifdef CONFIG_SLAB - /* For SLAB assign tags based on the object index in the freelist. */ - return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object); -#else /* - * For SLUB assign a random tag during slab creation, otherwise reuse + * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU, + * assign a random tag during slab creation, otherwise reuse * the already assigned tag. */ return init ? kasan_random_tag() : get_tag(object); -#endif } void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, @@ -197,8 +208,8 @@ void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, return (void *)object; } -static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, - unsigned long ip, bool quarantine, bool init) +static inline bool poison_slab_object(struct kmem_cache *cache, void *object, + unsigned long ip, bool init) { void *tagged_object; @@ -208,16 +219,12 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, tagged_object = object; object = kasan_reset_tag(object); - if (is_kfence_address(object)) - return false; - - if (unlikely(nearest_obj(cache, virt_to_slab(object), object) != - object)) { + if (unlikely(nearest_obj(cache, virt_to_slab(object), object) != object)) { kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_INVALID_FREE); return true; } - /* RCU slabs could be legally used after free within the RCU period */ + /* RCU slabs could be legally used after free within the RCU period. */ if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) return false; @@ -229,22 +236,44 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE), KASAN_SLAB_FREE, init); - if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine)) - return false; - if (kasan_stack_collection_enabled()) kasan_save_free_info(cache, tagged_object); - return kasan_quarantine_put(cache, object); + return false; } bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip, bool init) { - return ____kasan_slab_free(cache, object, ip, true, init); + if (is_kfence_address(object)) + return false; + + /* + * If the object is buggy, do not let slab put the object onto the + * freelist. The object will thus never be allocated again and its + * metadata will never get released. + */ + if (poison_slab_object(cache, object, ip, init)) + return true; + + /* + * If the object is put into quarantine, do not let slab put the object + * onto the freelist for now. The object's metadata is kept until the + * object gets evicted from quarantine. + */ + if (kasan_quarantine_put(cache, object)) + return true; + + /* + * Note: Keep per-object metadata to allow KASAN print stack traces for + * use-after-free-before-realloc bugs. + */ + + /* Let slab put the object onto the freelist. */ + return false; } -static inline bool ____kasan_kfree_large(void *ptr, unsigned long ip) +static inline bool check_page_allocation(void *ptr, unsigned long ip) { if (!kasan_arch_is_ready()) return false; @@ -259,40 +288,28 @@ static inline bool ____kasan_kfree_large(void *ptr, unsigned long ip) return true; } - /* - * The object will be poisoned by kasan_poison_pages() or - * kasan_slab_free_mempool(). - */ - return false; } void __kasan_kfree_large(void *ptr, unsigned long ip) { - ____kasan_kfree_large(ptr, ip); + check_page_allocation(ptr, ip); + + /* The object will be poisoned by kasan_poison_pages(). */ } -void __kasan_slab_free_mempool(void *ptr, unsigned long ip) +static inline void unpoison_slab_object(struct kmem_cache *cache, void *object, + gfp_t flags, bool init) { - struct folio *folio; - - folio = virt_to_folio(ptr); - /* - * Even though this function is only called for kmem_cache_alloc and - * kmalloc backed mempool allocations, those allocations can still be - * !PageSlab() when the size provided to kmalloc is larger than - * KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc. + * Unpoison the whole object. For kmalloc() allocations, + * poison_kmalloc_redzone() will do precise poisoning. */ - if (unlikely(!folio_test_slab(folio))) { - if (____kasan_kfree_large(ptr, ip)) - return; - kasan_poison(ptr, folio_size(folio), KASAN_PAGE_FREE, false); - } else { - struct slab *slab = folio_slab(folio); + kasan_unpoison(object, cache->object_size, init); - ____kasan_slab_free(slab->slab_cache, ptr, ip, false, false); - } + /* Save alloc info (if possible) for non-kmalloc() allocations. */ + if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache)) + kasan_save_alloc_info(cache, object, flags); } void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, @@ -317,39 +334,18 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, tag = assign_tag(cache, object, false); tagged_object = set_tag(object, tag); - /* - * Unpoison the whole object. - * For kmalloc() allocations, kasan_kmalloc() will do precise poisoning. - */ - kasan_unpoison(tagged_object, cache->object_size, init); - - /* Save alloc info (if possible) for non-kmalloc() allocations. */ - if (kasan_stack_collection_enabled() && !is_kmalloc_cache(cache)) - kasan_save_alloc_info(cache, tagged_object, flags); + /* Unpoison the object and save alloc info for non-kmalloc() allocations. */ + unpoison_slab_object(cache, tagged_object, flags, init); return tagged_object; } -static inline void *____kasan_kmalloc(struct kmem_cache *cache, +static inline void poison_kmalloc_redzone(struct kmem_cache *cache, const void *object, size_t size, gfp_t flags) { unsigned long redzone_start; unsigned long redzone_end; - if (gfpflags_allow_blocking(flags)) - kasan_quarantine_reduce(); - - if (unlikely(object == NULL)) - return NULL; - - if (is_kfence_address(kasan_reset_tag(object))) - return (void *)object; - - /* - * The object has already been unpoisoned by kasan_slab_alloc() for - * kmalloc() or by kasan_krealloc() for krealloc(). - */ - /* * The redzone has byte-level precision for the generic mode. * Partially poison the last object granule to cover the unaligned @@ -373,34 +369,34 @@ static inline void *____kasan_kmalloc(struct kmem_cache *cache, if (kasan_stack_collection_enabled() && is_kmalloc_cache(cache)) kasan_save_alloc_info(cache, (void *)object, flags); - /* Keep the tag that was set by kasan_slab_alloc(). */ - return (void *)object; } void * __must_check __kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size, gfp_t flags) { - return ____kasan_kmalloc(cache, object, size, flags); + if (gfpflags_allow_blocking(flags)) + kasan_quarantine_reduce(); + + if (unlikely(object == NULL)) + return NULL; + + if (is_kfence_address(object)) + return (void *)object; + + /* The object has already been unpoisoned by kasan_slab_alloc(). */ + poison_kmalloc_redzone(cache, object, size, flags); + + /* Keep the tag that was set by kasan_slab_alloc(). */ + return (void *)object; } EXPORT_SYMBOL(__kasan_kmalloc); -void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, +static inline void poison_kmalloc_large_redzone(const void *ptr, size_t size, gfp_t flags) { unsigned long redzone_start; unsigned long redzone_end; - if (gfpflags_allow_blocking(flags)) - kasan_quarantine_reduce(); - - if (unlikely(ptr == NULL)) - return NULL; - - /* - * The object has already been unpoisoned by kasan_unpoison_pages() for - * alloc_pages() or by kasan_krealloc() for krealloc(). - */ - /* * The redzone has byte-level precision for the generic mode. * Partially poison the last object granule to cover the unaligned @@ -410,12 +406,25 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, kasan_poison_last_granule(ptr, size); /* Poison the aligned part of the redzone. */ - redzone_start = round_up((unsigned long)(ptr + size), - KASAN_GRANULE_SIZE); + redzone_start = round_up((unsigned long)(ptr + size), KASAN_GRANULE_SIZE); redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr)); kasan_poison((void *)redzone_start, redzone_end - redzone_start, KASAN_PAGE_REDZONE, false); +} + +void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, + gfp_t flags) +{ + if (gfpflags_allow_blocking(flags)) + kasan_quarantine_reduce(); + + if (unlikely(ptr == NULL)) + return NULL; + /* The object has already been unpoisoned by kasan_unpoison_pages(). */ + poison_kmalloc_large_redzone(ptr, size, flags); + + /* Keep the tag that was set by alloc_pages(). */ return (void *)ptr; } @@ -423,9 +432,15 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag { struct slab *slab; + if (gfpflags_allow_blocking(flags)) + kasan_quarantine_reduce(); + if (unlikely(object == ZERO_SIZE_PTR)) return (void *)object; + if (is_kfence_address(object)) + return (void *)object; + /* * Unpoison the object's data. * Part of it might already have been unpoisoned, but it's unknown @@ -437,9 +452,91 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag /* Piggy-back on kmalloc() instrumentation to poison the redzone. */ if (unlikely(!slab)) - return __kasan_kmalloc_large(object, size, flags); + poison_kmalloc_large_redzone(object, size, flags); else - return ____kasan_kmalloc(slab->slab_cache, object, size, flags); + poison_kmalloc_redzone(slab->slab_cache, object, size, flags); + + return (void *)object; +} + +bool __kasan_mempool_poison_pages(struct page *page, unsigned int order, + unsigned long ip) +{ + unsigned long *ptr; + + if (unlikely(PageHighMem(page))) + return true; + + /* Bail out if allocation was excluded due to sampling. */ + if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && + page_kasan_tag(page) == KASAN_TAG_KERNEL) + return true; + + ptr = page_address(page); + + if (check_page_allocation(ptr, ip)) + return false; + + kasan_poison(ptr, PAGE_SIZE << order, KASAN_PAGE_FREE, false); + + return true; +} + +void __kasan_mempool_unpoison_pages(struct page *page, unsigned int order, + unsigned long ip) +{ + __kasan_unpoison_pages(page, order, false); +} + +bool __kasan_mempool_poison_object(void *ptr, unsigned long ip) +{ + struct folio *folio = virt_to_folio(ptr); + struct slab *slab; + + /* + * This function can be called for large kmalloc allocation that get + * their memory from page_alloc. Thus, the folio might not be a slab. + */ + if (unlikely(!folio_test_slab(folio))) { + if (check_page_allocation(ptr, ip)) + return false; + kasan_poison(ptr, folio_size(folio), KASAN_PAGE_FREE, false); + return true; + } + + if (is_kfence_address(ptr)) + return false; + + slab = folio_slab(folio); + return !poison_slab_object(slab->slab_cache, ptr, ip, false); +} + +void __kasan_mempool_unpoison_object(void *ptr, size_t size, unsigned long ip) +{ + struct slab *slab; + gfp_t flags = 0; /* Might be executing under a lock. */ + + slab = virt_to_slab(ptr); + + /* + * This function can be called for large kmalloc allocation that get + * their memory from page_alloc. + */ + if (unlikely(!slab)) { + kasan_unpoison(ptr, size, false); + poison_kmalloc_large_redzone(ptr, size, flags); + return; + } + + if (is_kfence_address(ptr)) + return; + + /* Unpoison the object and save alloc info for non-kmalloc() allocations. */ + unpoison_slab_object(slab->slab_cache, ptr, size, flags); + + /* Poison the redzone and save alloc info for kmalloc() allocations. */ + if (is_kmalloc_cache(slab->slab_cache)) + poison_kmalloc_redzone(slab->slab_cache, ptr, size, flags); } bool __kasan_check_byte(const void *address, unsigned long ip) |