diff options
Diffstat (limited to 'mm/kasan')
| -rw-r--r-- | mm/kasan/Makefile | 8 | ||||
| -rw-r--r-- | mm/kasan/common.c | 177 | ||||
| -rw-r--r-- | mm/kasan/generic.c | 154 | ||||
| -rw-r--r-- | mm/kasan/hw_tags.c | 39 | ||||
| -rw-r--r-- | mm/kasan/kasan.h | 171 | ||||
| -rw-r--r-- | mm/kasan/kasan_test.c | 1457 | ||||
| -rw-r--r-- | mm/kasan/kasan_test_module.c | 141 | ||||
| -rw-r--r-- | mm/kasan/report.c | 138 | ||||
| -rw-r--r-- | mm/kasan/report_generic.c | 46 | ||||
| -rw-r--r-- | mm/kasan/report_tags.c | 123 | ||||
| -rw-r--r-- | mm/kasan/sw_tags.c | 5 | ||||
| -rw-r--r-- | mm/kasan/tags.c | 143 |
12 files changed, 2209 insertions, 393 deletions
diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile index 1f84df9c302e..d4837bff3b60 100644 --- a/mm/kasan/Makefile +++ b/mm/kasan/Makefile @@ -35,7 +35,15 @@ CFLAGS_shadow.o := $(CC_FLAGS_KASAN_RUNTIME) CFLAGS_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_KASAN_TEST := $(CFLAGS_KASAN) -fno-builtin $(call cc-disable-warning, vla) + +CFLAGS_kasan_test.o := $(CFLAGS_KASAN_TEST) +CFLAGS_kasan_test_module.o := $(CFLAGS_KASAN_TEST) + obj-y := common.o report.o obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o tags.o report_tags.o obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o tags.o report_tags.o + +obj-$(CONFIG_KASAN_KUNIT_TEST) += kasan_test.o +obj-$(CONFIG_KASAN_MODULE_TEST) += kasan_test_module.o diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 69f583855c8b..833bf2cfd2a3 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -30,13 +30,20 @@ #include "kasan.h" #include "../slab.h" +struct slab *kasan_addr_to_slab(const void *addr) +{ + if (virt_addr_valid(addr)) + return virt_to_slab(addr); + return NULL; +} + depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc) { 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(entries, nr_entries, 0, flags, can_alloc); } void kasan_set_track(struct kasan_track *track, gfp_t flags) @@ -88,17 +95,6 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) } #endif /* CONFIG_KASAN_STACK */ -/* - * Only allow cache merging when stack collection is disabled and no metadata - * is present. - */ -slab_flags_t __kasan_never_merge(void) -{ - if (kasan_stack_collection_enabled()) - return SLAB_KASAN; - return 0; -} - void __kasan_unpoison_pages(struct page *page, unsigned int order, bool init) { u8 tag; @@ -121,132 +117,11 @@ void __kasan_poison_pages(struct page *page, unsigned int order, bool init) KASAN_PAGE_FREE, init); } -/* - * Adaptive redzone policy taken from the userspace AddressSanitizer runtime. - * For larger allocations larger redzones are used. - */ -static inline unsigned int optimal_redzone(unsigned int object_size) -{ - return - 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; -} - -void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, - slab_flags_t *flags) -{ - unsigned int ok_size; - unsigned int optimal_size; - - /* - * SLAB_KASAN is used to mark caches as ones that are sanitized by - * KASAN. Currently this flag is used in two places: - * 1. In slab_ksize() when calculating the size of the accessible - * memory within the object. - * 2. In slab_common.c to prevent merging of sanitized caches. - */ - *flags |= SLAB_KASAN; - - if (!kasan_stack_collection_enabled()) - return; - - ok_size = *size; - - /* Add alloc meta into redzone. */ - cache->kasan_info.alloc_meta_offset = *size; - *size += sizeof(struct kasan_alloc_meta); - - /* - * If alloc meta doesn't fit, don't add it. - * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal - * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for - * larger sizes. - */ - if (*size > KMALLOC_MAX_SIZE) { - cache->kasan_info.alloc_meta_offset = 0; - *size = ok_size; - /* Continue, since free meta might still fit. */ - } - - /* Only the generic mode uses free meta or flexible redzones. */ - if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) { - cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META; - return; - } - - /* - * Add free meta into redzone when it's not possible to store - * it in the object. This is the case when: - * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can - * be touched after it was freed, or - * 2. Object has a constructor, which means it's expected to - * retain its content until the next allocation, or - * 3. Object is too small. - * Otherwise cache->kasan_info.free_meta_offset = 0 is implied. - */ - if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor || - cache->object_size < sizeof(struct kasan_free_meta)) { - ok_size = *size; - - cache->kasan_info.free_meta_offset = *size; - *size += sizeof(struct kasan_free_meta); - - /* If free meta doesn't fit, don't add it. */ - if (*size > KMALLOC_MAX_SIZE) { - cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META; - *size = ok_size; - } - } - - /* Calculate size with optimal redzone. */ - optimal_size = cache->object_size + optimal_redzone(cache->object_size); - /* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */ - if (optimal_size > KMALLOC_MAX_SIZE) - optimal_size = KMALLOC_MAX_SIZE; - /* Use optimal size if the size with added metas is not large enough. */ - if (*size < optimal_size) - *size = optimal_size; -} - void __kasan_cache_create_kmalloc(struct kmem_cache *cache) { cache->kasan_info.is_kmalloc = true; } -size_t __kasan_metadata_size(struct kmem_cache *cache) -{ - if (!kasan_stack_collection_enabled()) - return 0; - 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); -} - -struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, - const void *object) -{ - if (!cache->kasan_info.alloc_meta_offset) - return NULL; - return kasan_reset_tag(object) + cache->kasan_info.alloc_meta_offset; -} - -#ifdef CONFIG_KASAN_GENERIC -struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, - const void *object) -{ - BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); - if (cache->kasan_info.free_meta_offset == KASAN_NO_FREE_META) - return NULL; - return kasan_reset_tag(object) + cache->kasan_info.free_meta_offset; -} -#endif - void __kasan_poison_slab(struct slab *slab) { struct page *page = slab_page(slab); @@ -312,13 +187,9 @@ static inline u8 assign_tag(struct kmem_cache *cache, void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, const void *object) { - struct kasan_alloc_meta *alloc_meta; - - if (kasan_stack_collection_enabled()) { - alloc_meta = kasan_get_alloc_meta(cache, object); - if (alloc_meta) - __memset(alloc_meta, 0, sizeof(*alloc_meta)); - } + /* Initialize per-object metadata if it is present. */ + if (kasan_requires_meta()) + kasan_init_object_meta(cache, object); /* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */ object = set_tag(object, assign_tag(cache, object, true)); @@ -329,13 +200,11 @@ void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip, bool quarantine, bool init) { - u8 tag; void *tagged_object; if (!kasan_arch_is_ready()) return false; - tag = get_tag(object); tagged_object = object; object = kasan_reset_tag(object); @@ -364,7 +233,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, return false; if (kasan_stack_collection_enabled()) - kasan_set_free_info(cache, object, tag); + kasan_save_free_info(cache, tagged_object); return kasan_quarantine_put(cache, object); } @@ -423,20 +292,6 @@ void __kasan_slab_free_mempool(void *ptr, unsigned long ip) } } -static void set_alloc_info(struct kmem_cache *cache, void *object, - gfp_t flags, bool is_kmalloc) -{ - struct kasan_alloc_meta *alloc_meta; - - /* Don't save alloc info for kmalloc caches in kasan_slab_alloc(). */ - if (cache->kasan_info.is_kmalloc && !is_kmalloc) - return; - - alloc_meta = kasan_get_alloc_meta(cache, object); - if (alloc_meta) - kasan_set_track(&alloc_meta->alloc_track, flags); -} - void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags, bool init) { @@ -466,8 +321,8 @@ void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, kasan_unpoison(tagged_object, cache->object_size, init); /* Save alloc info (if possible) for non-kmalloc() allocations. */ - if (kasan_stack_collection_enabled()) - set_alloc_info(cache, (void *)object, flags, false); + if (kasan_stack_collection_enabled() && !cache->kasan_info.is_kmalloc) + kasan_save_alloc_info(cache, tagged_object, flags); return tagged_object; } @@ -512,8 +367,8 @@ static inline void *____kasan_kmalloc(struct kmem_cache *cache, * Save alloc info (if possible) for kmalloc() allocations. * This also rewrites the alloc info when called from kasan_krealloc(). */ - if (kasan_stack_collection_enabled()) - set_alloc_info(cache, (void *)object, flags, true); + if (kasan_stack_collection_enabled() && cache->kasan_info.is_kmalloc) + kasan_save_alloc_info(cache, (void *)object, flags); /* Keep the tag that was set by kasan_slab_alloc(). */ return (void *)object; diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 437fcc7e77cf..d8b5590f9484 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -328,6 +328,139 @@ DEFINE_ASAN_SET_SHADOW(f3); DEFINE_ASAN_SET_SHADOW(f5); DEFINE_ASAN_SET_SHADOW(f8); +/* Only allow cache merging when no per-object metadata is present. */ +slab_flags_t kasan_never_merge(void) +{ + if (!kasan_requires_meta()) + return 0; + return SLAB_KASAN; +} + +/* + * Adaptive redzone policy taken from the userspace AddressSanitizer runtime. + * For larger allocations larger redzones are used. + */ +static inline unsigned int optimal_redzone(unsigned int object_size) +{ + return + 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; +} + +void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, + slab_flags_t *flags) +{ + unsigned int ok_size; + unsigned int optimal_size; + + if (!kasan_requires_meta()) + return; + + /* + * SLAB_KASAN is used to mark caches that are sanitized by KASAN + * and that thus have per-object metadata. + * Currently this flag is used in two places: + * 1. In slab_ksize() to account for per-object metadata when + * calculating the size of the accessible memory within the object. + * 2. In slab_common.c via kasan_never_merge() to prevent merging of + * caches with per-object metadata. + */ + *flags |= SLAB_KASAN; + + ok_size = *size; + + /* Add alloc meta into redzone. */ + cache->kasan_info.alloc_meta_offset = *size; + *size += sizeof(struct kasan_alloc_meta); + + /* + * If alloc meta doesn't fit, don't add it. + * This can only happen with SLAB, as it has KMALLOC_MAX_SIZE equal + * to KMALLOC_MAX_CACHE_SIZE and doesn't fall back to page_alloc for + * larger sizes. + */ + if (*size > KMALLOC_MAX_SIZE) { + cache->kasan_info.alloc_meta_offset = 0; + *size = ok_size; + /* Continue, since free meta might still fit. */ + } + + /* + * Add free meta into redzone when it's not possible to store + * it in the object. This is the case when: + * 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can + * be touched after it was freed, or + * 2. Object has a constructor, which means it's expected to + * retain its content until the next allocation, or + * 3. Object is too small. + * Otherwise cache->kasan_info.free_meta_offset = 0 is implied. + */ + if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor || + cache->object_size < sizeof(struct kasan_free_meta)) { + ok_size = *size; + + cache->kasan_info.free_meta_offset = *size; + *size += sizeof(struct kasan_free_meta); + + /* If free meta doesn't fit, don't add it. */ + if (*size > KMALLOC_MAX_SIZE) { + cache->kasan_info.free_meta_offset = KASAN_NO_FREE_META; + *size = ok_size; + } + } + + /* Calculate size with optimal redzone. */ + optimal_size = cache->object_size + optimal_redzone(cache->object_size); + /* Limit it with KMALLOC_MAX_SIZE (relevant for SLAB only). */ + if (optimal_size > KMALLOC_MAX_SIZE) + optimal_size = KMALLOC_MAX_SIZE; + /* Use optimal size if the size with added metas is not large enough. */ + if (*size < optimal_size) + *size = optimal_size; +} + +struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, + const void *object) +{ + if (!cache->kasan_info.alloc_meta_offset) + return NULL; + return (void *)object + cache->kasan_info.alloc_meta_offset; +} + +struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, + const void *object) +{ + BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); + if (cache->kasan_info.free_meta_offset == KASAN_NO_FREE_META) + return NULL; + return (void *)object + cache->kasan_info.free_meta_offset; +} + +void kasan_init_object_meta(struct kmem_cache *cache, const void *object) +{ + struct kasan_alloc_meta *alloc_meta; + + alloc_meta = kasan_get_alloc_meta(cache, object); + if (alloc_meta) + __memset(alloc_meta, 0, sizeof(*alloc_meta)); +} + +size_t kasan_metadata_size(struct kmem_cache *cache) +{ + if (!kasan_requires_meta()) + return 0; + return (cache->kasan_info.alloc_meta_offset ? + sizeof(struct kasan_alloc_meta) : 0) + + ((cache->kasan_info.free_meta_offset && + cache->kasan_info.free_meta_offset != KASAN_NO_FREE_META) ? + sizeof(struct kasan_free_meta) : 0); +} + static void __kasan_record_aux_stack(void *addr, bool can_alloc) { struct slab *slab = kasan_addr_to_slab(addr); @@ -358,8 +491,16 @@ void kasan_record_aux_stack_noalloc(void *addr) return __kasan_record_aux_stack(addr, false); } -void kasan_set_free_info(struct kmem_cache *cache, - void *object, u8 tag) +void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) +{ + struct kasan_alloc_meta *alloc_meta; + + alloc_meta = kasan_get_alloc_meta(cache, object); + if (alloc_meta) + kasan_set_track(&alloc_meta->alloc_track, flags); +} + +void kasan_save_free_info(struct kmem_cache *cache, void *object) { struct kasan_free_meta *free_meta; @@ -371,12 +512,3 @@ void kasan_set_free_info(struct kmem_cache *cache, /* The object was freed and has free track set. */ *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK; } - -struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, - void *object, u8 tag) -{ - if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREETRACK) - return NULL; - /* Free meta must be present with KASAN_SLAB_FREETRACK. */ - return &kasan_get_free_meta(cache, object)->free_track; -} diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 9ad8eff71b28..b22c4f461cb0 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -38,16 +38,9 @@ enum kasan_arg_vmalloc { KASAN_ARG_VMALLOC_ON, }; -enum kasan_arg_stacktrace { - KASAN_ARG_STACKTRACE_DEFAULT, - KASAN_ARG_STACKTRACE_OFF, - KASAN_ARG_STACKTRACE_ON, -}; - static enum kasan_arg kasan_arg __ro_after_init; static enum kasan_arg_mode kasan_arg_mode __ro_after_init; static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; -static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; /* * Whether KASAN is enabled at all. @@ -66,9 +59,6 @@ EXPORT_SYMBOL_GPL(kasan_mode); /* Whether to enable vmalloc tagging. */ DEFINE_STATIC_KEY_TRUE(kasan_flag_vmalloc); -/* Whether to collect alloc/free stack traces. */ -DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); - /* kasan=off/on */ static int __init early_kasan_flag(char *arg) { @@ -122,23 +112,6 @@ static int __init early_kasan_flag_vmalloc(char *arg) } early_param("kasan.vmalloc", early_kasan_flag_vmalloc); -/* kasan.stacktrace=off/on */ -static int __init early_kasan_flag_stacktrace(char *arg) -{ - if (!arg) - return -EINVAL; - - if (!strcmp(arg, "off")) - kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF; - else if (!strcmp(arg, "on")) - kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON; - else - return -EINVAL; - - return 0; -} -early_param("kasan.stacktrace", early_kasan_flag_stacktrace); - static inline const char *kasan_mode_info(void) { if (kasan_mode == KASAN_MODE_ASYNC) @@ -213,17 +186,7 @@ void __init kasan_init_hw_tags(void) break; } - switch (kasan_arg_stacktrace) { - case KASAN_ARG_STACKTRACE_DEFAULT: - /* Default is specified by kasan_flag_stacktrace definition. */ - break; - case KASAN_ARG_STACKTRACE_OFF: - static_branch_disable(&kasan_flag_stacktrace); - break; - case KASAN_ARG_STACKTRACE_ON: - static_branch_enable(&kasan_flag_stacktrace); - break; - } + kasan_init_tags(); /* KASAN is now initialized, enable it. */ static_branch_enable(&kasan_flag_enabled); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 01c03e45acd4..abbcc1b0eec5 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -2,18 +2,37 @@ #ifndef __MM_KASAN_KASAN_H #define __MM_KASAN_KASAN_H +#include <linux/atomic.h> #include <linux/kasan.h> #include <linux/kasan-tags.h> #include <linux/kfence.h> #include <linux/stackdepot.h> -#ifdef CONFIG_KASAN_HW_TAGS +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) #include <linux/static_key.h> + +DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace); + +static inline bool kasan_stack_collection_enabled(void) +{ + return static_branch_unlikely(&kasan_flag_stacktrace); +} + +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + +static inline bool kasan_stack_collection_enabled(void) +{ + return true; +} + +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + +#ifdef CONFIG_KASAN_HW_TAGS + #include "../slab.h" DECLARE_STATIC_KEY_TRUE(kasan_flag_vmalloc); -DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace); enum kasan_mode { KASAN_MODE_SYNC, @@ -28,11 +47,6 @@ static inline bool kasan_vmalloc_enabled(void) return static_branch_likely(&kasan_flag_vmalloc); } -static inline bool kasan_stack_collection_enabled(void) -{ - return static_branch_unlikely(&kasan_flag_stacktrace); -} - static inline bool kasan_async_fault_possible(void) { return kasan_mode == KASAN_MODE_ASYNC || kasan_mode == KASAN_MODE_ASYMM; @@ -43,12 +57,7 @@ static inline bool kasan_sync_fault_possible(void) return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM; } -#else - -static inline bool kasan_stack_collection_enabled(void) -{ - return true; -} +#else /* CONFIG_KASAN_HW_TAGS */ static inline bool kasan_async_fault_possible(void) { @@ -60,7 +69,31 @@ static inline bool kasan_sync_fault_possible(void) return true; } -#endif +#endif /* CONFIG_KASAN_HW_TAGS */ + +#ifdef CONFIG_KASAN_GENERIC + +/* Generic KASAN uses per-object metadata to store stack traces. */ +static inline bool kasan_requires_meta(void) +{ + /* + * Technically, Generic KASAN always collects stack traces right now. + * However, let's use kasan_stack_collection_enabled() in case the + * kasan.stacktrace command-line argument is changed to affect + * Generic KASAN. + */ + return kasan_stack_collection_enabled(); +} + +#else /* CONFIG_KASAN_GENERIC */ + +/* Tag-based KASAN modes do not use per-object metadata. */ +static inline bool kasan_requires_meta(void) +{ + return false; +} + +#endif /* CONFIG_KASAN_GENERIC */ #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) @@ -122,6 +155,13 @@ static inline bool kasan_sync_fault_possible(void) #define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE) #define META_ROWS_AROUND_ADDR 2 +#define KASAN_STACK_DEPTH 64 + +struct kasan_track { + u32 pid; + depot_stack_handle_t stack; +}; + enum kasan_report_type { KASAN_REPORT_ACCESS, KASAN_REPORT_INVALID_FREE, @@ -129,12 +169,22 @@ enum kasan_report_type { }; struct kasan_report_info { + /* Filled in by kasan_report_*(). */ enum kasan_report_type type; void *access_addr; - void *first_bad_addr; size_t access_size; bool is_write; unsigned long ip; + + /* Filled in by the common reporting code. */ + void *first_bad_addr; + struct kmem_cache *cache; + void *object; + + /* Filled in by the mode-specific reporting code. */ + const char *bug_type; + struct kasan_track alloc_track; + struct kasan_track free_track; }; /* Do not change the struct layout: compiler ABI. */ @@ -160,33 +210,14 @@ struct kasan_global { #endif }; -/* Structures for keeping alloc and free tracks. */ +/* Structures for keeping alloc and free meta. */ -#define KASAN_STACK_DEPTH 64 - -struct kasan_track { - u32 pid; - depot_stack_handle_t stack; -}; - -#if defined(CONFIG_KASAN_TAGS_IDENTIFY) && defined(CONFIG_KASAN_SW_TAGS) -#define KASAN_NR_FREE_STACKS 5 -#else -#define KASAN_NR_FREE_STACKS 1 -#endif +#ifdef CONFIG_KASAN_GENERIC struct kasan_alloc_meta { struct kasan_track alloc_track; - /* Generic mode stores free track in kasan_free_meta. */ -#ifdef CONFIG_KASAN_GENERIC + /* Free track is stored in kasan_free_meta. */ depot_stack_handle_t aux_stack[2]; -#else - struct kasan_track free_track[KASAN_NR_FREE_STACKS]; -#endif -#ifdef CONFIG_KASAN_TAGS_IDENTIFY - u8 free_pointer_tag[KASAN_NR_FREE_STACKS]; - u8 free_track_idx; -#endif }; struct qlist_node { @@ -205,12 +236,31 @@ struct qlist_node { * After that, slab allocator stores the freelist pointer in the object. */ struct kasan_free_meta { -#ifdef CONFIG_KASAN_GENERIC struct qlist_node quarantine_link; struct kasan_track free_track; -#endif }; +#endif /* CONFIG_KASAN_GENERIC */ + +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) + +struct kasan_stack_ring_entry { + void *ptr; + size_t size; + u32 pid; + depot_stack_handle_t stack; + bool is_free; +}; + +struct kasan_stack_ring { + rwlock_t lock; + size_t size; + atomic64_t pos; + struct kasan_stack_ring_entry *entries; +}; + +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + #if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) /* Used in KUnit-compatible KASAN tests. */ struct kunit_kasan_status { @@ -219,13 +269,6 @@ struct kunit_kasan_status { }; #endif -struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, - const void *object); -#ifdef CONFIG_KASAN_GENERIC -struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, - const void *object); -#endif - #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) static inline const void *kasan_shadow_to_mem(const void *shadow_addr) @@ -260,34 +303,50 @@ static inline bool addr_has_metadata(const void *addr) #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ +void *kasan_find_first_bad_addr(void *addr, size_t size); +void kasan_complete_mode_report_info(struct kasan_report_info *info); +void kasan_metadata_fetch_row(char *buffer, void *row); + #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) void kasan_print_tags(u8 addr_tag, const void *addr); #else static inline void kasan_print_tags(u8 addr_tag, const void *addr) { } #endif -void *kasan_find_first_bad_addr(void *addr, size_t size); -const char *kasan_get_bug_type(struct kasan_report_info *info); -void kasan_metadata_fetch_row(char *buffer, void *row); - #if defined(CONFIG_KASAN_STACK) void kasan_print_address_stack_frame(const void *addr); #else static inline void kasan_print_address_stack_frame(const void *addr) { } #endif +#ifdef CONFIG_KASAN_GENERIC +void kasan_print_aux_stacks(struct kmem_cache *cache, const void *object); +#else +static inline void kasan_print_aux_stacks(struct kmem_cache *cache, const void *object) { } +#endif + bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip); void kasan_report_invalid_free(void *object, unsigned long ip, enum kasan_report_type type); -struct page *kasan_addr_to_page(const void *addr); struct slab *kasan_addr_to_slab(const void *addr); +#ifdef CONFIG_KASAN_GENERIC +void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size); +void kasan_init_object_meta(struct kmem_cache *cache, const void *object); +struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache, + const void *object); +struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache, + const void *object); +#else +static inline void kasan_init_cache_meta(struct kmem_cache *cache, unsigned int *size) { } +static inline void kasan_init_object_meta(struct kmem_cache *cache, const void *object) { } +#endif + depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc); 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); +void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags); +void kasan_save_free_info(struct kmem_cache *cache, void *object); #if defined(CONFIG_KASAN_GENERIC) && \ (defined(CONFIG_SLAB) || defined(CONFIG_SLUB)) @@ -358,6 +417,10 @@ static inline void kasan_enable_tagging(void) { } #endif /* CONFIG_KASAN_HW_TAGS */ +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) +void __init kasan_init_tags(void); +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) void kasan_force_async_fault(void); diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c new file mode 100644 index 000000000000..0d59098f0876 --- /dev/null +++ b/mm/kasan/kasan_test.c @@ -0,0 +1,1457 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <a.ryabinin@samsung.com> + */ + +#include <linux/bitops.h> +#include <linux/delay.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/module.h> +#include <linux/printk.h> +#include <linux/random.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/uaccess.h> +#include <linux/io.h> +#include <linux/vmalloc.h> +#include <linux/set_memory.h> + +#include <asm/page.h> + +#include <kunit/test.h> + +#include "kasan.h" + +#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE) + +/* + * Some tests use these global variables to store return values from function + * calls that could otherwise be eliminated by the compiler as dead code. + */ +void *kasan_ptr_result; +int kasan_int_result; + +static struct kunit_resource resource; +static struct kunit_kasan_status test_status; +static bool multishot; + +/* + * Temporarily enable multi-shot mode. Otherwise, KASAN would only report the + * first detected bug and panic the kernel if panic_on_warn is enabled. For + * hardware tag-based KASAN also allow tag checking to be reenabled for each + * test, see the comment for KUNIT_EXPECT_KASAN_FAIL(). + */ +static int kasan_test_init(struct kunit *test) +{ + if (!kasan_enabled()) { + kunit_err(test, "can't run KASAN tests with KASAN disabled"); + return -1; + } + + multishot = kasan_save_enable_multi_shot(); + test_status.report_found = false; + test_status.sync_fault = false; + kunit_add_named_resource(test, NULL, NULL, &resource, + "kasan_status", &test_status); + return 0; +} + +static void kasan_test_exit(struct kunit *test) +{ + kasan_restore_multi_shot(multishot); + KUNIT_EXPECT_FALSE(test, test_status.report_found); +} + +/** + * KUNIT_EXPECT_KASAN_FAIL() - check that the executed expression produces a + * KASAN report; causes a test failure otherwise. This relies on a KUnit + * resource named "kasan_status". Do not use this name for KUnit resources + * outside of KASAN tests. + * + * For hardware tag-based KASAN, when a synchronous tag fault happens, tag + * checking is auto-disabled. When this happens, this test handler reenables + * tag checking. As tag checking can be only disabled or enabled per CPU, + * this handler disables migration (preemption). + * + * Since the compiler doesn't see that the expression can change the test_status + * fields, it can reorder or optimize away the accesses to those fields. + * Use READ/WRITE_ONCE() for the accesses and compiler barriers around the + * expression to prevent that. + * + * In between KUNIT_EXPECT_KASAN_FAIL checks, test_status.report_found is kept + * as false. This allows detecting KASAN reports that happen outside of the + * checks by asserting !test_status.report_found at the start of + * KUNIT_EXPECT_KASAN_FAIL and in kasan_test_exit. + */ +#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \ + if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ + kasan_sync_fault_possible()) \ + migrate_disable(); \ + KUNIT_EXPECT_FALSE(test, READ_ONCE(test_status.report_found)); \ + barrier(); \ + expression; \ + barrier(); \ + if (kasan_async_fault_possible()) \ + kasan_force_async_fault(); \ + if (!READ_ONCE(test_status.report_found)) { \ + KUNIT_FAIL(test, KUNIT_SUBTEST_INDENT "KASAN failure " \ + "expected in \"" #expression \ + "\", but none occurred"); \ + } \ + if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \ + kasan_sync_fault_possible()) { \ + if (READ_ONCE(test_status.report_found) && \ + READ_ONCE(test_status.sync_fault)) \ + kasan_enable_tagging(); \ + migrate_enable(); \ + } \ + WRITE_ONCE(test_status.report_found, false); \ +} while (0) + +#define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \ + if (!IS_ENABLED(config)) \ + kunit_skip((test), "Test requires " #config "=y"); \ +} while (0) + +#define KASAN_TEST_NEEDS_CONFIG_OFF(test, config) do { \ + if (IS_ENABLED(config)) \ + kunit_skip((test), "Test requires " #config "=n"); \ +} while (0) + +static void kmalloc_oob_right(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE - 5; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + /* + * An unaligned access past the requested kmalloc size. + * Only generic KASAN can precisely detect these. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 'x'); + + /* + * An aligned access into the first out-of-bounds granule that falls + * within the aligned kmalloc object. + */ + KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + 5] = 'y'); + + /* Out-of-bounds access past the aligned kmalloc object. */ + KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = + ptr[size + KASAN_GRANULE_SIZE + 5]); + + kfree(ptr); +} + +static void kmalloc_oob_left(struct kunit *test) +{ + char *ptr; + size_t size = 15; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, *ptr = *(ptr - 1)); + kfree(ptr); +} + +static void kmalloc_node_oob_right(struct kunit *test) +{ + char *ptr; + size_t size = 4096; + + ptr = kmalloc_node(size, GFP_KERNEL, 0); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]); + kfree(ptr); +} + +/* + * These kmalloc_pagealloc_* tests try allocating a memory chunk that doesn't + * fit into a slab cache and therefore is allocated via the page allocator + * fallback. Since this kind of fallback is only implemented for SLUB, these + * tests are limited to that allocator. + */ +static void kmalloc_pagealloc_oob_right(struct kunit *test) +{ + char *ptr; + size_t size = KMALLOC_MAX_CACHE_SIZE + 10; + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0); + + kfree(ptr); +} + +static void kmalloc_pagealloc_uaf(struct kunit *test) +{ + char *ptr; + size_t size = KMALLOC_MAX_CACHE_SIZE + 10; + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + kfree(ptr); + + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); +} + +static void kmalloc_pagealloc_invalid_free(struct kunit *test) +{ + char *ptr; + size_t size = KMALLOC_MAX_CACHE_SIZE + 10; + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + KUNIT_EXPECT_KASAN_FAIL(test, kfree(ptr + 1)); +} + +static void pagealloc_oob_right(struct kunit *test) +{ + char *ptr; + struct page *pages; + size_t order = 4; + size_t size = (1UL << (PAGE_SHIFT + order)); + + /* + * With generic KASAN page allocations have no redzones, thus + * out-of-bounds detection is not guaranteed. + * See https://bugzilla.kernel.org/show_bug.cgi?id=210503. + */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + pages = alloc_pages(GFP_KERNEL, order); + ptr = page_address(pages); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]); + free_pages((unsigned long)ptr, order); +} + +static void pagealloc_uaf(struct kunit *test) +{ + char *ptr; + struct page *pages; + size_t order = 4; + + pages = alloc_pages(GFP_KERNEL, order); + ptr = page_address(pages); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + free_pages((unsigned long)ptr, order); + + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); +} + +static void kmalloc_large_oob_right(struct kunit *test) +{ + char *ptr; + size_t size = KMALLOC_MAX_CACHE_SIZE - 256; + + /* + * Allocate a chunk that is large enough, but still fits into a slab + * and does not trigger the page allocator fallback in SLUB. + */ + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0); + kfree(ptr); +} + +static void krealloc_more_oob_helper(struct kunit *test, + size_t size1, size_t size2) +{ + char *ptr1, *ptr2; + size_t middle; + + KUNIT_ASSERT_LT(test, size1, size2); + middle = size1 + (size2 - size1) / 2; + + ptr1 = kmalloc(size1, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + + ptr2 = krealloc(ptr1, size2, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + + /* Suppress -Warray-bounds warnings. */ + OPTIMIZER_HIDE_VAR(ptr2); + + /* All offsets up to size2 must be accessible. */ + ptr2[size1 - 1] = 'x'; + ptr2[size1] = 'x'; + ptr2[middle] = 'x'; + ptr2[size2 - 1] = 'x'; + + /* Generic mode is precise, so unaligned size2 must be inaccessible. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); + + /* For all modes first aligned offset after size2 must be inaccessible. */ + KUNIT_EXPECT_KASAN_FAIL(test, + ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); + + kfree(ptr2); +} + +static void krealloc_less_oob_helper(struct kunit *test, + size_t size1, size_t size2) +{ + char *ptr1, *ptr2; + size_t middle; + + KUNIT_ASSERT_LT(test, size2, size1); + middle = size2 + (size1 - size2) / 2; + + ptr1 = kmalloc(size1, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + + ptr2 = krealloc(ptr1, size2, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + + /* Suppress -Warray-bounds warnings. */ + OPTIMIZER_HIDE_VAR(ptr2); + + /* Must be accessible for all modes. */ + ptr2[size2 - 1] = 'x'; + + /* Generic mode is precise, so unaligned size2 must be inaccessible. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x'); + + /* For all modes first aligned offset after size2 must be inaccessible. */ + KUNIT_EXPECT_KASAN_FAIL(test, + ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x'); + + /* + * For all modes all size2, middle, and size1 should land in separate + * granules and thus the latter two offsets should be inaccessible. + */ + KUNIT_EXPECT_LE(test, round_up(size2, KASAN_GRANULE_SIZE), + round_down(middle, KASAN_GRANULE_SIZE)); + KUNIT_EXPECT_LE(test, round_up(middle, KASAN_GRANULE_SIZE), + round_down(size1, KASAN_GRANULE_SIZE)); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[middle] = 'x'); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1 - 1] = 'x'); + KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size1] = 'x'); + + kfree(ptr2); +} + +static void krealloc_more_oob(struct kunit *test) +{ + krealloc_more_oob_helper(test, 201, 235); +} + +static void krealloc_less_oob(struct kunit *test) +{ + krealloc_less_oob_helper(test, 235, 201); +} + +static void krealloc_pagealloc_more_oob(struct kunit *test) +{ + /* page_alloc fallback in only implemented for SLUB. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + krealloc_more_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 201, + KMALLOC_MAX_CACHE_SIZE + 235); +} + +static void krealloc_pagealloc_less_oob(struct kunit *test) +{ + /* page_alloc fallback in only implemented for SLUB. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); + + krealloc_less_oob_helper(test, KMALLOC_MAX_CACHE_SIZE + 235, + KMALLOC_MAX_CACHE_SIZE + 201); +} + +/* + * Check that krealloc() detects a use-after-free, returns NULL, + * and doesn't unpoison the freed object. + */ +static void krealloc_uaf(struct kunit *test) +{ + char *ptr1, *ptr2; + int size1 = 201; + int size2 = 235; + + ptr1 = kmalloc(size1, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + kfree(ptr1); + + KUNIT_EXPECT_KASAN_FAIL(test, ptr2 = krealloc(ptr1, size2, GFP_KERNEL)); + KUNIT_ASSERT_NULL(test, ptr2); + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)ptr1); +} + +static void kmalloc_oob_16(struct kunit *test) +{ + struct { + u64 words[2]; + } *ptr1, *ptr2; + + /* This test is specifically crafted for the generic mode. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + + ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + + ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + + OPTIMIZER_HIDE_VAR(ptr1); + OPTIMIZER_HIDE_VAR(ptr2); + KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2); + kfree(ptr1); + kfree(ptr2); +} + +static void kmalloc_uaf_16(struct kunit *test) +{ + struct { + u64 words[2]; + } *ptr1, *ptr2; + + ptr1 = kmalloc(sizeof(*ptr1), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + + ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + kfree(ptr2); + + KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2); + kfree(ptr1); +} + +/* + * Note: in the memset tests below, the written range touches both valid and + * invalid memory. This makes sure that the instrumentation does not only check + * the starting address but the whole range. + */ + +static void kmalloc_oob_memset_2(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 1, 0, 2)); + kfree(ptr); +} + +static void kmalloc_oob_memset_4(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 3, 0, 4)); + kfree(ptr); +} + +static void kmalloc_oob_memset_8(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 7, 0, 8)); + kfree(ptr); +} + +static void kmalloc_oob_memset_16(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr + size - 15, 0, 16)); + kfree(ptr); +} + +static void kmalloc_oob_in_memset(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, + memset(ptr, 0, size + KASAN_GRANULE_SIZE)); + kfree(ptr); +} + +static void kmalloc_memmove_negative_size(struct kunit *test) +{ + char *ptr; + size_t size = 64; + size_t invalid_size = -2; + + /* + * Hardware tag-based mode doesn't check memmove for negative size. + * As a result, this test introduces a side-effect memory corruption, + * which can result in a crash. + */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_HW_TAGS); + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + memset((char *)ptr, 0, 64); + OPTIMIZER_HIDE_VAR(ptr); + OPTIMIZER_HIDE_VAR(invalid_size); + KUNIT_EXPECT_KASAN_FAIL(test, + memmove((char *)ptr, (char *)ptr + 4, invalid_size)); + kfree(ptr); +} + +static void kmalloc_memmove_invalid_size(struct kunit *test) +{ + char *ptr; + size_t size = 64; + size_t invalid_size = size; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + memset((char *)ptr, 0, 64); + OPTIMIZER_HIDE_VAR(ptr); + OPTIMIZER_HIDE_VAR(invalid_size); + KUNIT_EXPECT_KASAN_FAIL(test, + memmove((char *)ptr, (char *)ptr + 4, invalid_size)); + kfree(ptr); +} + +static void kmalloc_uaf(struct kunit *test) +{ + char *ptr; + size_t size = 10; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + kfree(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[8]); +} + +static void kmalloc_uaf_memset(struct kunit *test) +{ + char *ptr; + size_t size = 33; + + /* + * Only generic KASAN uses quarantine, which is required to avoid a + * kernel memory corruption this test causes. + */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + kfree(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, memset(ptr, 0, size)); +} + +static void kmalloc_uaf2(struct kunit *test) +{ + char *ptr1, *ptr2; + size_t size = 43; + int counter = 0; + +again: + ptr1 = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + + kfree(ptr1); + + ptr2 = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + + /* + * For tag-based KASAN ptr1 and ptr2 tags might happen to be the same. + * Allow up to 16 attempts at generating different tags. + */ + if (!IS_ENABLED(CONFIG_KASAN_GENERIC) && ptr1 == ptr2 && counter++ < 16) { + kfree(ptr2); + goto again; + } + + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[40]); + KUNIT_EXPECT_PTR_NE(test, ptr1, ptr2); + + kfree(ptr2); +} + +/* + * Check that KASAN detects use-after-free when another object was allocated in + * the same slot. Relevant for the tag-based modes, which do not use quarantine. + */ +static void kmalloc_uaf3(struct kunit *test) +{ + char *ptr1, *ptr2; + size_t size = 100; + + /* This test is specifically crafted for tag-based modes. */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + ptr1 = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1); + kfree(ptr1); + + ptr2 = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2); + kfree(ptr2); + + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr1)[8]); +} + +static void kfree_via_page(struct kunit *test) +{ + char *ptr; + size_t size = 8; + struct page *page; + unsigned long offset; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + page = virt_to_page(ptr); + offset = offset_in_page(ptr); + kfree(page_address(page) + offset); +} + +static void kfree_via_phys(struct kunit *test) +{ + char *ptr; + size_t size = 8; + phys_addr_t phys; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + phys = virt_to_phys(ptr); + kfree(phys_to_virt(phys)); +} + +static void kmem_cache_oob(struct kunit *test) +{ + char *p; + size_t size = 200; + struct kmem_cache *cache; + + cache = kmem_cache_create("test_cache", size, 0, 0, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + + p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) { + kunit_err(test, "Allocation failed: %s\n", __func__); + kmem_cache_destroy(cache); + return; + } + + KUNIT_EXPECT_KASAN_FAIL(test, *p = p[size + OOB_TAG_OFF]); + + kmem_cache_free(cache, p); + kmem_cache_destroy(cache); +} + +static void kmem_cache_accounted(struct kunit *test) +{ + int i; + char *p; + size_t size = 200; + struct kmem_cache *cache; + + cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + + /* + * Several allocations with a delay to allow for lazy per memcg kmem + * cache creation. + */ + for (i = 0; i < 5; i++) { + p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) + goto free_cache; + + kmem_cache_free(cache, p); + msleep(100); + } + +free_cache: + kmem_cache_destroy(cache); +} + +static void kmem_cache_bulk(struct kunit *test) +{ + struct kmem_cache *cache; + size_t size = 200; + char *p[10]; + bool ret; + int i; + + cache = kmem_cache_create("test_cache", size, 0, 0, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + + ret = kmem_cache_alloc_bulk(cache, GFP_KERNEL, ARRAY_SIZE(p), (void **)&p); + if (!ret) { + kunit_err(test, "Allocation failed: %s\n", __func__); + kmem_cache_destroy(cache); + return; + } + + for (i = 0; i < ARRAY_SIZE(p); i++) + p[i][0] = p[i][size - 1] = 42; + + kmem_cache_free_bulk(cache, ARRAY_SIZE(p), (void **)&p); + kmem_cache_destroy(cache); +} + +static char global_array[10]; + +static void kasan_global_oob_right(struct kunit *test) +{ + /* + * Deliberate out-of-bounds access. To prevent CONFIG_UBSAN_LOCAL_BOUNDS + * from failing here and panicking the kernel, access the array via a + * volatile pointer, which will prevent the compiler from being able to + * determine the array bounds. + * + * This access uses a volatile pointer to char (char *volatile) rather + * than the more conventional pointer to volatile char (volatile char *) + * because we want to prevent the compiler from making inferences about + * the pointer itself (i.e. its array bounds), not the data that it + * refers to. + */ + char *volatile array = global_array; + char *p = &array[ARRAY_SIZE(global_array) + 3]; + + /* Only generic mode instruments globals. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); +} + +static void kasan_global_oob_left(struct kunit *test) +{ + char *volatile array = global_array; + char *p = array - 3; + + /* + * GCC is known to fail this test, skip it. + * See https://bugzilla.kernel.org/show_bug.cgi?id=215051. + */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_CC_IS_CLANG); + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); +} + +/* Check that ksize() makes the whole object accessible. */ +static void ksize_unpoisons_memory(struct kunit *test) +{ + char *ptr; + size_t size = 123, real_size; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + real_size = ksize(ptr); + + OPTIMIZER_HIDE_VAR(ptr); + + /* This access shouldn't trigger a KASAN report. */ + ptr[size] = 'x'; + + /* This one must. */ + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size]); + + kfree(ptr); +} + +/* + * Check that a use-after-free is detected by ksize() and via normal accesses + * after it. + */ +static void ksize_uaf(struct kunit *test) +{ + char *ptr; + int size = 128 - KASAN_GRANULE_SIZE; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + kfree(ptr); + + OPTIMIZER_HIDE_VAR(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr)); + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); +} + +static void kasan_stack_oob(struct kunit *test) +{ + char stack_array[10]; + /* See comment in kasan_global_oob_right. */ + char *volatile array = stack_array; + char *p = &array[ARRAY_SIZE(stack_array) + OOB_TAG_OFF]; + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); + + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); +} + +static void kasan_alloca_oob_left(struct kunit *test) +{ + volatile int i = 10; + char alloca_array[i]; + /* See comment in kasan_global_oob_right. */ + char *volatile array = alloca_array; + char *p = array - 1; + + /* Only generic mode instruments dynamic allocas. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); + + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); +} + +static void kasan_alloca_oob_right(struct kunit *test) +{ + volatile int i = 10; + char alloca_array[i]; + /* See comment in kasan_global_oob_right. */ + char *volatile array = alloca_array; + char *p = array + i; + + /* Only generic mode instruments dynamic allocas. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_STACK); + + KUNIT_EXPECT_KASAN_FAIL(test, *(volatile char *)p); +} + +static void kmem_cache_double_free(struct kunit *test) +{ + char *p; + size_t size = 200; + struct kmem_cache *cache; + + cache = kmem_cache_create("test_cache", size, 0, 0, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + + p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) { + kunit_err(test, "Allocation failed: %s\n", __func__); + kmem_cache_destroy(cache); + return; + } + + kmem_cache_free(cache, p); + KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p)); + kmem_cache_destroy(cache); +} + +static void kmem_cache_invalid_free(struct kunit *test) +{ + char *p; + size_t size = 200; + struct kmem_cache *cache; + + cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU, + NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + + p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) { + kunit_err(test, "Allocation failed: %s\n", __func__); + kmem_cache_destroy(cache); + return; + } + + /* Trigger invalid free, the object doesn't get freed. */ + KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_free(cache, p + 1)); + + /* + * Properly free the object to prevent the "Objects remaining in + * test_cache on __kmem_cache_shutdown" BUG failure. + */ + kmem_cache_free(cache, p); + + kmem_cache_destroy(cache); +} + +static void empty_cache_ctor(void *object) { } + +static void kmem_cache_double_destroy(struct kunit *test) +{ + struct kmem_cache *cache; + + /* Provide a constructor to prevent cache merging. */ + cache = kmem_cache_create("test_cache", 200, 0, 0, empty_cache_ctor); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cache); + kmem_cache_destroy(cache); + KUNIT_EXPECT_KASAN_FAIL(test, kmem_cache_destroy(cache)); +} + +static void kasan_memchr(struct kunit *test) +{ + char *ptr; + size_t size = 24; + + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); + + if (OOB_TAG_OFF) + size = round_up(size, OOB_TAG_OFF); + + ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + OPTIMIZER_HIDE_VAR(ptr); + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, + kasan_ptr_result = memchr(ptr, '1', size + 1)); + + kfree(ptr); +} + +static void kasan_memcmp(struct kunit *test) +{ + char *ptr; + size_t size = 24; + int arr[9]; + + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); + + if (OOB_TAG_OFF) + size = round_up(size, OOB_TAG_OFF); + + ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + memset(arr, 0, sizeof(arr)); + + OPTIMIZER_HIDE_VAR(ptr); + OPTIMIZER_HIDE_VAR(size); + KUNIT_EXPECT_KASAN_FAIL(test, + kasan_int_result = memcmp(ptr, arr, size+1)); + kfree(ptr); +} + +static void kasan_strings(struct kunit *test) +{ + char *ptr; + size_t size = 24; + + /* + * str* functions are not instrumented with CONFIG_AMD_MEM_ENCRYPT. + * See https://bugzilla.kernel.org/show_bug.cgi?id=206337 for details. + */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_AMD_MEM_ENCRYPT); + + ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + kfree(ptr); + + /* + * Try to cause only 1 invalid access (less spam in dmesg). + * For that we need ptr to point to zeroed byte. + * Skip metadata that could be stored in freed object so ptr + * will likely point to zeroed byte. + */ + ptr += 16; + KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strchr(ptr, '1')); + + KUNIT_EXPECT_KASAN_FAIL(test, kasan_ptr_result = strrchr(ptr, '1')); + + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strcmp(ptr, "2")); + + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strncmp(ptr, "2", 1)); + + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strlen(ptr)); + + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = strnlen(ptr, 1)); +} + +static void kasan_bitops_modify(struct kunit *test, int nr, void *addr) +{ + KUNIT_EXPECT_KASAN_FAIL(test, set_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __set_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, clear_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, clear_bit_unlock(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __clear_bit_unlock(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, change_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __change_bit(nr, addr)); +} + +static void kasan_bitops_test_and_modify(struct kunit *test, int nr, void *addr) +{ + KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __test_and_set_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, test_and_set_bit_lock(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, test_and_clear_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __test_and_clear_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, test_and_change_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, __test_and_change_bit(nr, addr)); + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = test_bit(nr, addr)); + +#if defined(clear_bit_unlock_is_negative_byte) + KUNIT_EXPECT_KASAN_FAIL(test, kasan_int_result = + clear_bit_unlock_is_negative_byte(nr, addr)); +#endif +} + +static void kasan_bitops_generic(struct kunit *test) +{ + long *bits; + + /* This test is specifically crafted for the generic mode. */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC); + + /* + * Allocate 1 more byte, which causes kzalloc to round up to 16 bytes; + * this way we do not actually corrupt other memory. + */ + bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits); + + /* + * Below calls try to access bit within allocated memory; however, the + * below accesses are still out-of-bounds, since bitops are defined to + * operate on the whole long the bit is in. + */ + kasan_bitops_modify(test, BITS_PER_LONG, bits); + + /* + * Below calls try to access bit beyond allocated memory. + */ + kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, bits); + + kfree(bits); +} + +static void kasan_bitops_tags(struct kunit *test) +{ + long *bits; + + /* This test is specifically crafted for tag-based modes. */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + /* kmalloc-64 cache will be used and the last 16 bytes will be the redzone. */ + bits = kzalloc(48, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits); + + /* Do the accesses past the 48 allocated bytes, but within the redone. */ + kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48); + kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void *)bits + 48); + + kfree(bits); +} + +static void kmalloc_double_kzfree(struct kunit *test) +{ + char *ptr; + size_t size = 16; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + kfree_sensitive(ptr); + KUNIT_EXPECT_KASAN_FAIL(test, kfree_sensitive(ptr)); +} + +static void vmalloc_helpers_tags(struct kunit *test) +{ + void *ptr; + + /* This test is intended for tag-based modes. */ + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC); + + ptr = vmalloc(PAGE_SIZE); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + /* Check that the returned pointer is tagged. */ + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + + /* Make sure exported vmalloc helpers handle tagged pointers. */ + KUNIT_ASSERT_TRUE(test, is_vmalloc_addr(ptr)); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vmalloc_to_page(ptr)); + +#if !IS_MODULE(CONFIG_KASAN_KUNIT_TEST) + { + int rv; + + /* Make sure vmalloc'ed memory permissions can be changed. */ + rv = set_memory_ro((unsigned long)ptr, 1); + KUNIT_ASSERT_GE(test, rv, 0); + rv = set_memory_rw((unsigned long)ptr, 1); + KUNIT_ASSERT_GE(test, rv, 0); + } +#endif + + vfree(ptr); +} + +static void vmalloc_oob(struct kunit *test) +{ + char *v_ptr, *p_ptr; + struct page *page; + size_t size = PAGE_SIZE / 2 - KASAN_GRANULE_SIZE - 5; + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC); + + v_ptr = vmalloc(size); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr); + + OPTIMIZER_HIDE_VAR(v_ptr); + + /* + * We have to be careful not to hit the guard page in vmalloc tests. + * The MMU will catch that and crash us. + */ + + /* Make sure in-bounds accesses are valid. */ + v_ptr[0] = 0; + v_ptr[size - 1] = 0; + + /* + * An unaligned access past the requested vmalloc size. + * Only generic KASAN can precisely detect these. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)v_ptr)[size]); + + /* An aligned access into the first out-of-bounds granule. */ + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)v_ptr)[size + 5]); + + /* Check that in-bounds accesses to the physical page are valid. */ + page = vmalloc_to_page(v_ptr); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, page); + p_ptr = page_address(page); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr); + p_ptr[0] = 0; + + vfree(v_ptr); + + /* + * We can't check for use-after-unmap bugs in this nor in the following + * vmalloc tests, as the page might be fully unmapped and accessing it + * will crash the kernel. + */ +} + +static void vmap_tags(struct kunit *test) +{ + char *p_ptr, *v_ptr; + struct page *p_page, *v_page; + + /* + * This test is specifically crafted for the software tag-based mode, + * the only tag-based mode that poisons vmap mappings. + */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS); + + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_VMALLOC); + + p_page = alloc_pages(GFP_KERNEL, 1); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_page); + p_ptr = page_address(p_page); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr); + + v_ptr = vmap(&p_page, 1, VM_MAP, PAGE_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr); + + /* + * We can't check for out-of-bounds bugs in this nor in the following + * vmalloc tests, as allocations have page granularity and accessing + * the guard page will crash the kernel. + */ + + KUNIT_EXPECT_GE(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_KERNEL); + + /* Make sure that in-bounds accesses through both pointers work. */ + *p_ptr = 0; + *v_ptr = 0; + + /* Make sure vmalloc_to_page() correctly recovers the page pointer. */ + v_page = vmalloc_to_page(v_ptr); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_page); + KUNIT_EXPECT_PTR_EQ(test, p_page, v_page); + + vunmap(v_ptr); + free_pages((unsigned long)p_ptr, 1); +} + +static void vm_map_ram_tags(struct kunit *test) +{ + char *p_ptr, *v_ptr; + struct page *page; + + /* + * This test is specifically crafted for the software tag-based mode, + * the only tag-based mode that poisons vm_map_ram mappings. + */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS); + + page = alloc_pages(GFP_KERNEL, 1); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, page); + p_ptr = page_address(page); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p_ptr); + + v_ptr = vm_map_ram(&page, 1, -1); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, v_ptr); + + KUNIT_EXPECT_GE(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(v_ptr), (u8)KASAN_TAG_KERNEL); + + /* Make sure that in-bounds accesses through both pointers work. */ + *p_ptr = 0; + *v_ptr = 0; + + vm_unmap_ram(v_ptr, 1); + free_pages((unsigned long)p_ptr, 1); +} + +static void vmalloc_percpu(struct kunit *test) +{ + char __percpu *ptr; + int cpu; + + /* + * This test is specifically crafted for the software tag-based mode, + * the only tag-based mode that poisons percpu mappings. + */ + KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_SW_TAGS); + + ptr = __alloc_percpu(PAGE_SIZE, PAGE_SIZE); + + for_each_possible_cpu(cpu) { + char *c_ptr = per_cpu_ptr(ptr, cpu); + + KUNIT_EXPECT_GE(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(c_ptr), (u8)KASAN_TAG_KERNEL); + + /* Make sure that in-bounds accesses don't crash the kernel. */ + *c_ptr = 0; + } + + free_percpu(ptr); +} + +/* + * Check that the assigned pointer tag falls within the [KASAN_TAG_MIN, + * KASAN_TAG_KERNEL) range (note: excluding the match-all tag) for tag-based + * modes. + */ +static void match_all_not_assigned(struct kunit *test) +{ + char *ptr; + struct page *pages; + int i, size, order; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + for (i = 0; i < 256; i++) { + size = prandom_u32_max(1024) + 1; + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + kfree(ptr); + } + + for (i = 0; i < 256; i++) { + order = prandom_u32_max(4) + 1; + pages = alloc_pages(GFP_KERNEL, order); + ptr = page_address(pages); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + free_pages((unsigned long)ptr, order); + } + + if (!IS_ENABLED(CONFIG_KASAN_VMALLOC)) + return; + + for (i = 0; i < 256; i++) { + size = prandom_u32_max(1024) + 1; + ptr = vmalloc(size); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN); + KUNIT_EXPECT_LT(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + vfree(ptr); + } +} + +/* Check that 0xff works as a match-all pointer tag for tag-based modes. */ +static void match_all_ptr_tag(struct kunit *test) +{ + char *ptr; + u8 tag; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + ptr = kmalloc(128, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + /* Backup the assigned tag. */ + tag = get_tag(ptr); + KUNIT_EXPECT_NE(test, tag, (u8)KASAN_TAG_KERNEL); + + /* Reset the tag to 0xff.*/ + ptr = set_tag(ptr, KASAN_TAG_KERNEL); + + /* This access shouldn't trigger a KASAN report. */ + *ptr = 0; + + /* Recover the pointer tag and free. */ + ptr = set_tag(ptr, tag); + kfree(ptr); +} + +/* Check that there are no match-all memory tags for tag-based modes. */ +static void match_all_mem_tag(struct kunit *test) +{ + char *ptr; + int tag; + + KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC); + + ptr = kmalloc(128, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + KUNIT_EXPECT_NE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_KERNEL); + + /* For each possible tag value not matching the pointer tag. */ + for (tag = KASAN_TAG_MIN; tag <= KASAN_TAG_KERNEL; tag++) { + if (tag == get_tag(ptr)) + continue; + + /* Mark the first memory granule with the chosen memory tag. */ + kasan_poison(ptr, KASAN_GRANULE_SIZE, (u8)tag, false); + + /* This access must cause a KASAN report. */ + KUNIT_EXPECT_KASAN_FAIL(test, *ptr = 0); + } + + /* Recover the memory tag and free. */ + kasan_poison(ptr, KASAN_GRANULE_SIZE, get_tag(ptr), false); + kfree(ptr); +} + +static struct kunit_case kasan_kunit_test_cases[] = { + KUNIT_CASE(kmalloc_oob_right), + KUNIT_CASE(kmalloc_oob_left), + KUNIT_CASE(kmalloc_node_oob_right), + KUNIT_CASE(kmalloc_pagealloc_oob_right), + KUNIT_CASE(kmalloc_pagealloc_uaf), + KUNIT_CASE(kmalloc_pagealloc_invalid_free), + KUNIT_CASE(pagealloc_oob_right), + KUNIT_CASE(pagealloc_uaf), + KUNIT_CASE(kmalloc_large_oob_right), + KUNIT_CASE(krealloc_more_oob), + KUNIT_CASE(krealloc_less_oob), + KUNIT_CASE(krealloc_pagealloc_more_oob), + KUNIT_CASE(krealloc_pagealloc_less_oob), + KUNIT_CASE(krealloc_uaf), + KUNIT_CASE(kmalloc_oob_16), + KUNIT_CASE(kmalloc_uaf_16), + KUNIT_CASE(kmalloc_oob_in_memset), + KUNIT_CASE(kmalloc_oob_memset_2), + KUNIT_CASE(kmalloc_oob_memset_4), + KUNIT_CASE(kmalloc_oob_memset_8), + KUNIT_CASE(kmalloc_oob_memset_16), + KUNIT_CASE(kmalloc_memmove_negative_size), + KUNIT_CASE(kmalloc_memmove_invalid_size), + KUNIT_CASE(kmalloc_uaf), + KUNIT_CASE(kmalloc_uaf_memset), + KUNIT_CASE(kmalloc_uaf2), + KUNIT_CASE(kmalloc_uaf3), + KUNIT_CASE(kfree_via_page), + KUNIT_CASE(kfree_via_phys), + KUNIT_CASE(kmem_cache_oob), + KUNIT_CASE(kmem_cache_accounted), + KUNIT_CASE(kmem_cache_bulk), + KUNIT_CASE(kasan_global_oob_right), + KUNIT_CASE(kasan_global_oob_left), + KUNIT_CASE(kasan_stack_oob), + KUNIT_CASE(kasan_alloca_oob_left), + KUNIT_CASE(kasan_alloca_oob_right), + KUNIT_CASE(ksize_unpoisons_memory), + KUNIT_CASE(ksize_uaf), + KUNIT_CASE(kmem_cache_double_free), + KUNIT_CASE(kmem_cache_invalid_free), + KUNIT_CASE(kmem_cache_double_destroy), + KUNIT_CASE(kasan_memchr), + KUNIT_CASE(kasan_memcmp), + KUNIT_CASE(kasan_strings), + KUNIT_CASE(kasan_bitops_generic), + KUNIT_CASE(kasan_bitops_tags), + KUNIT_CASE(kmalloc_double_kzfree), + KUNIT_CASE(vmalloc_helpers_tags), + KUNIT_CASE(vmalloc_oob), + KUNIT_CASE(vmap_tags), + KUNIT_CASE(vm_map_ram_tags), + KUNIT_CASE(vmalloc_percpu), + KUNIT_CASE(match_all_not_assigned), + KUNIT_CASE(match_all_ptr_tag), + KUNIT_CASE(match_all_mem_tag), + {} +}; + +static struct kunit_suite kasan_kunit_test_suite = { + .name = "kasan", + .init = kasan_test_init, + .test_cases = kasan_kunit_test_cases, + .exit = kasan_test_exit, +}; + +kunit_test_suite(kasan_kunit_test_suite); + +MODULE_LICENSE("GPL"); diff --git a/mm/kasan/kasan_test_module.c b/mm/kasan/kasan_test_module.c new file mode 100644 index 000000000000..e4ca82dc2c16 --- /dev/null +++ b/mm/kasan/kasan_test_module.c @@ -0,0 +1,141 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <a.ryabinin@samsung.com> + */ + +#define pr_fmt(fmt) "kasan test: %s " fmt, __func__ + +#include <linux/mman.h> +#include <linux/module.h> +#include <linux/printk.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +#include "kasan.h" + +static noinline void __init copy_user_test(void) +{ + char *kmem; + char __user *usermem; + size_t size = 128 - KASAN_GRANULE_SIZE; + int __maybe_unused unused; + + kmem = kmalloc(size, GFP_KERNEL); + if (!kmem) + return; + + usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_ANONYMOUS | MAP_PRIVATE, 0); + if (IS_ERR(usermem)) { + pr_err("Failed to allocate user memory\n"); + kfree(kmem); + return; + } + + OPTIMIZER_HIDE_VAR(size); + + pr_info("out-of-bounds in copy_from_user()\n"); + unused = copy_from_user(kmem, usermem, size + 1); + + pr_info("out-of-bounds in copy_to_user()\n"); + unused = copy_to_user(usermem, kmem, size + 1); + + pr_info("out-of-bounds in __copy_from_user()\n"); + unused = __copy_from_user(kmem, usermem, size + 1); + + pr_info("out-of-bounds in __copy_to_user()\n"); + unused = __copy_to_user(usermem, kmem, size + 1); + + pr_info("out-of-bounds in __copy_from_user_inatomic()\n"); + unused = __copy_from_user_inatomic(kmem, usermem, size + 1); + + pr_info("out-of-bounds in __copy_to_user_inatomic()\n"); + unused = __copy_to_user_inatomic(usermem, kmem, size + 1); + + pr_info("out-of-bounds in strncpy_from_user()\n"); + unused = strncpy_from_user(kmem, usermem, size + 1); + + vm_munmap((unsigned long)usermem, PAGE_SIZE); + kfree(kmem); +} + +static struct kasan_rcu_info { + int i; + struct rcu_head rcu; +} *global_rcu_ptr; + +static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp) +{ + struct kasan_rcu_info *fp = container_of(rp, + struct kasan_rcu_info, rcu); + + kfree(fp); + ((volatile struct kasan_rcu_info *)fp)->i; +} + +static noinline void __init kasan_rcu_uaf(void) +{ + struct kasan_rcu_info *ptr; + + pr_info("use-after-free in kasan_rcu_reclaim\n"); + ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL); + if (!ptr) { + pr_err("Allocation failed\n"); + return; + } + + global_rcu_ptr = rcu_dereference_protected(ptr, NULL); + call_rcu(&global_rcu_ptr->rcu, kasan_rcu_reclaim); +} + +static noinline void __init kasan_workqueue_work(struct work_struct *work) +{ + kfree(work); +} + +static noinline void __init kasan_workqueue_uaf(void) +{ + struct workqueue_struct *workqueue; + struct work_struct *work; + + workqueue = create_workqueue("kasan_wq_test"); + if (!workqueue) { + pr_err("Allocation failed\n"); + return; + } + work = kmalloc(sizeof(struct work_struct), GFP_KERNEL); + if (!work) { + pr_err("Allocation failed\n"); + return; + } + + INIT_WORK(work, kasan_workqueue_work); + queue_work(workqueue, work); + destroy_workqueue(workqueue); + + pr_info("use-after-free on workqueue\n"); + ((volatile struct work_struct *)work)->data; +} + +static int __init test_kasan_module_init(void) +{ + /* + * Temporarily enable multi-shot mode. Otherwise, KASAN would only + * report the first detected bug and panic the kernel if panic_on_warn + * is enabled. + */ + bool multishot = kasan_save_enable_multi_shot(); + + copy_user_test(); + kasan_rcu_uaf(); + kasan_workqueue_uaf(); + + kasan_restore_multi_shot(multishot); + return -EAGAIN; +} + +module_init(test_kasan_module_init); +MODULE_LICENSE("GPL"); diff --git a/mm/kasan/report.c b/mm/kasan/report.c index fe3f606b3a98..df3602062bfd 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -175,18 +175,14 @@ static void end_report(unsigned long *flags, void *addr) static void print_error_description(struct kasan_report_info *info) { - if (info->type == KASAN_REPORT_INVALID_FREE) { - pr_err("BUG: KASAN: invalid-free in %pS\n", (void *)info->ip); - return; - } + pr_err("BUG: KASAN: %s in %pS\n", info->bug_type, (void *)info->ip); - if (info->type == KASAN_REPORT_DOUBLE_FREE) { - pr_err("BUG: KASAN: double-free in %pS\n", (void *)info->ip); + if (info->type != KASAN_REPORT_ACCESS) { + pr_err("Free of addr %px by task %s/%d\n", + info->access_addr, current->comm, task_pid_nr(current)); return; } - pr_err("BUG: KASAN: %s in %pS\n", - kasan_get_bug_type(info), (void *)info->ip); if (info->access_size) pr_err("%s of size %zu at addr %px by task %s/%d\n", info->is_write ? "Write" : "Read", info->access_size, @@ -200,31 +196,21 @@ static void print_error_description(struct kasan_report_info *info) static void print_track(struct kasan_track *track, const char *prefix) { pr_err("%s by task %u:\n", prefix, track->pid); - if (track->stack) { + if (track->stack) stack_depot_print(track->stack); - } else { + else pr_err("(stack is not available)\n"); - } } -struct page *kasan_addr_to_page(const void *addr) +static inline struct page *addr_to_page(const void *addr) { - if ((addr >= (void *)PAGE_OFFSET) && - (addr < high_memory)) + if (virt_addr_valid(addr)) return virt_to_head_page(addr); return NULL; } -struct slab *kasan_addr_to_slab(const void *addr) -{ - if ((addr >= (void *)PAGE_OFFSET) && - (addr < high_memory)) - return virt_to_slab(addr); - return NULL; -} - -static void describe_object_addr(struct kmem_cache *cache, void *object, - const void *addr) +static void describe_object_addr(const void *addr, struct kmem_cache *cache, + void *object) { unsigned long access_addr = (unsigned long)addr; unsigned long object_addr = (unsigned long)object; @@ -252,46 +238,26 @@ static void describe_object_addr(struct kmem_cache *cache, void *object, (void *)(object_addr + cache->object_size)); } -static void describe_object_stacks(struct kmem_cache *cache, void *object, - const void *addr, u8 tag) +static void describe_object_stacks(struct kasan_report_info *info) { - struct kasan_alloc_meta *alloc_meta; - struct kasan_track *free_track; - - alloc_meta = kasan_get_alloc_meta(cache, object); - if (alloc_meta) { - print_track(&alloc_meta->alloc_track, "Allocated"); + if (info->alloc_track.stack) { + print_track(&info->alloc_track, "Allocated"); pr_err("\n"); } - free_track = kasan_get_free_track(cache, object, tag); - if (free_track) { - print_track(free_track, "Freed"); + if (info->free_track.stack) { + print_track(&info->free_track, "Freed"); pr_err("\n"); } -#ifdef CONFIG_KASAN_GENERIC - if (!alloc_meta) - return; - if (alloc_meta->aux_stack[0]) { - pr_err("Last potentially related work creation:\n"); - stack_depot_print(alloc_meta->aux_stack[0]); - pr_err("\n"); - } - if (alloc_meta->aux_stack[1]) { - pr_err("Second to last potentially related work creation:\n"); - stack_depot_print(alloc_meta->aux_stack[1]); - pr_err("\n"); - } -#endif + kasan_print_aux_stacks(info->cache, info->object); } -static void describe_object(struct kmem_cache *cache, void *object, - const void *addr, u8 tag) +static void describe_object(const void *addr, struct kasan_report_info *info) { if (kasan_stack_collection_enabled()) - describe_object_stacks(cache, object, addr, tag); - describe_object_addr(cache, object, addr); + describe_object_stacks(info); + describe_object_addr(addr, info->cache, info->object); } static inline bool kernel_or_module_addr(const void *addr) @@ -310,19 +276,16 @@ static inline bool init_task_stack_addr(const void *addr) sizeof(init_thread_union.stack)); } -static void print_address_description(void *addr, u8 tag) +static void print_address_description(void *addr, u8 tag, + struct kasan_report_info *info) { - struct page *page = kasan_addr_to_page(addr); + struct page *page = addr_to_page(addr); dump_stack_lvl(KERN_ERR); pr_err("\n"); - if (page && PageSlab(page)) { - struct slab *slab = page_slab(page); - struct kmem_cache *cache = slab->slab_cache; - void *object = nearest_obj(cache, slab, addr); - - describe_object(cache, object, addr, tag); + if (info->cache && info->object) { + describe_object(addr, info); pr_err("\n"); } @@ -420,23 +383,56 @@ static void print_memory_metadata(const void *addr) static void print_report(struct kasan_report_info *info) { - void *tagged_addr = info->access_addr; - void *untagged_addr = kasan_reset_tag(tagged_addr); - u8 tag = get_tag(tagged_addr); + void *addr = kasan_reset_tag(info->access_addr); + u8 tag = get_tag(info->access_addr); print_error_description(info); - if (addr_has_metadata(untagged_addr)) + if (addr_has_metadata(addr)) kasan_print_tags(tag, info->first_bad_addr); pr_err("\n"); - if (addr_has_metadata(untagged_addr)) { - print_address_description(untagged_addr, tag); + if (addr_has_metadata(addr)) { + print_address_description(addr, tag, info); print_memory_metadata(info->first_bad_addr); } else { dump_stack_lvl(KERN_ERR); } } +static void complete_report_info(struct kasan_report_info *info) +{ + void *addr = kasan_reset_tag(info->access_addr); + struct slab *slab; + + if (info->type == KASAN_REPORT_ACCESS) + info->first_bad_addr = kasan_find_first_bad_addr( + info->access_addr, info->access_size); + else + info->first_bad_addr = addr; + + slab = kasan_addr_to_slab(addr); + if (slab) { + info->cache = slab->slab_cache; + info->object = nearest_obj(info->cache, slab, addr); + } else + info->cache = info->object = NULL; + + switch (info->type) { + case KASAN_REPORT_INVALID_FREE: + info->bug_type = "invalid-free"; + break; + case KASAN_REPORT_DOUBLE_FREE: + info->bug_type = "double-free"; + break; + default: + /* bug_type filled in by kasan_complete_mode_report_info. */ + break; + } + + /* Fill in mode-specific report info fields. */ + kasan_complete_mode_report_info(info); +} + void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_type type) { unsigned long flags; @@ -452,13 +448,15 @@ void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_ty start_report(&flags, true); + memset(&info, 0, sizeof(info)); info.type = type; info.access_addr = ptr; - info.first_bad_addr = kasan_reset_tag(ptr); info.access_size = 0; info.is_write = false; info.ip = ip; + complete_report_info(&info); + print_report(&info); end_report(&flags, ptr); @@ -485,13 +483,15 @@ bool kasan_report(unsigned long addr, size_t size, bool is_write, start_report(&irq_flags, true); + memset(&info, 0, sizeof(info)); info.type = KASAN_REPORT_ACCESS; info.access_addr = ptr; - info.first_bad_addr = kasan_find_first_bad_addr(ptr, size); info.access_size = size; info.is_write = is_write; info.ip = ip; + complete_report_info(&info); + print_report(&info); end_report(&irq_flags, ptr); diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c index 6689fb9a919b..043c94b04605 100644 --- a/mm/kasan/report_generic.c +++ b/mm/kasan/report_generic.c @@ -109,7 +109,7 @@ static const char *get_wild_bug_type(struct kasan_report_info *info) return bug_type; } -const char *kasan_get_bug_type(struct kasan_report_info *info) +static const char *get_bug_type(struct kasan_report_info *info) { /* * If access_size is a negative number, then it has reason to be @@ -127,11 +127,55 @@ const char *kasan_get_bug_type(struct kasan_report_info *info) return get_wild_bug_type(info); } +void kasan_complete_mode_report_info(struct kasan_report_info *info) +{ + struct kasan_alloc_meta *alloc_meta; + struct kasan_free_meta *free_meta; + + if (!info->bug_type) + info->bug_type = get_bug_type(info); + + if (!info->cache || !info->object) + return; + + alloc_meta = kasan_get_alloc_meta(info->cache, info->object); + if (alloc_meta) + memcpy(&info->alloc_track, &alloc_meta->alloc_track, + sizeof(info->alloc_track)); + + if (*(u8 *)kasan_mem_to_shadow(info->object) == KASAN_SLAB_FREETRACK) { + /* Free meta must be present with KASAN_SLAB_FREETRACK. */ + free_meta = kasan_get_free_meta(info->cache, info->object); + memcpy(&info->free_track, &free_meta->free_track, + sizeof(info->free_track)); + } +} + void kasan_metadata_fetch_row(char *buffer, void *row) { memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); } +void kasan_print_aux_stacks(struct kmem_cache *cache, const void *object) +{ + struct kasan_alloc_meta *alloc_meta; + + alloc_meta = kasan_get_alloc_meta(cache, object); + if (!alloc_meta) + return; + + if (alloc_meta->aux_stack[0]) { + pr_err("Last potentially related work creation:\n"); + stack_depot_print(alloc_meta->aux_stack[0]); + pr_err("\n"); + } + if (alloc_meta->aux_stack[1]) { + pr_err("Second to last potentially related work creation:\n"); + stack_depot_print(alloc_meta->aux_stack[1]); + pr_err("\n"); + } +} + #ifdef CONFIG_KASAN_STACK static bool __must_check tokenize_frame_descr(const char **frame_descr, char *token, size_t max_tok_len, diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c index e25d2166e813..ecede06ef374 100644 --- a/mm/kasan/report_tags.c +++ b/mm/kasan/report_tags.c @@ -4,38 +4,14 @@ * Copyright (c) 2020 Google, Inc. */ +#include <linux/atomic.h> + #include "kasan.h" -#include "../slab.h" -const char *kasan_get_bug_type(struct kasan_report_info *info) -{ -#ifdef CONFIG_KASAN_TAGS_IDENTIFY - struct kasan_alloc_meta *alloc_meta; - struct kmem_cache *cache; - struct slab *slab; - const void *addr; - void *object; - u8 tag; - int i; - - tag = get_tag(info->access_addr); - addr = kasan_reset_tag(info->access_addr); - slab = kasan_addr_to_slab(addr); - if (slab) { - cache = slab->slab_cache; - object = nearest_obj(cache, slab, (void *)addr); - alloc_meta = kasan_get_alloc_meta(cache, object); - - if (alloc_meta) { - for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { - if (alloc_meta->free_pointer_tag[i] == tag) - return "use-after-free"; - } - } - return "out-of-bounds"; - } -#endif +extern struct kasan_stack_ring stack_ring; +static const char *get_common_bug_type(struct kasan_report_info *info) +{ /* * If access_size is a negative number, then it has reason to be * defined as out-of-bounds bug type. @@ -49,3 +25,92 @@ const char *kasan_get_bug_type(struct kasan_report_info *info) return "invalid-access"; } + +void kasan_complete_mode_report_info(struct kasan_report_info *info) +{ + unsigned long flags; + u64 pos; + struct kasan_stack_ring_entry *entry; + void *ptr; + u32 pid; + depot_stack_handle_t stack; + bool is_free; + bool alloc_found = false, free_found = false; + + if ((!info->cache || !info->object) && !info->bug_type) { + info->bug_type = get_common_bug_type(info); + return; + } + + write_lock_irqsave(&stack_ring.lock, flags); + + pos = atomic64_read(&stack_ring.pos); + + /* + * The loop below tries to find stack ring entries relevant to the + * buggy object. This is a best-effort process. + * + * First, another object with the same tag can be allocated in place of + * the buggy object. Also, since the number of entries is limited, the + * entries relevant to the buggy object can be overwritten. + */ + + for (u64 i = pos - 1; i != pos - 1 - stack_ring.size; i--) { + if (alloc_found && free_found) + break; + + entry = &stack_ring.entries[i % stack_ring.size]; + + /* Paired with smp_store_release() in save_stack_info(). */ + ptr = (void *)smp_load_acquire(&entry->ptr); + + if (kasan_reset_tag(ptr) != info->object || + get_tag(ptr) != get_tag(info->access_addr)) + continue; + + pid = READ_ONCE(entry->pid); + stack = READ_ONCE(entry->stack); + is_free = READ_ONCE(entry->is_free); + + if (is_free) { + /* + * Second free of the same object. + * Give up on trying to find the alloc entry. + */ + if (free_found) + break; + + info->free_track.pid = pid; + info->free_track.stack = stack; + free_found = true; + + /* + * If a free entry is found first, the bug is likely + * a use-after-free. + */ + if (!info->bug_type) + info->bug_type = "use-after-free"; + } else { + /* Second alloc of the same object. Give up. */ + if (alloc_found) + break; + + info->alloc_track.pid = pid; + info->alloc_track.stack = stack; + alloc_found = true; + + /* + * If an alloc entry is found first, the bug is likely + * an out-of-bounds. + */ + if (!info->bug_type) + info->bug_type = "slab-out-of-bounds"; + } + } + + write_unlock_irqrestore(&stack_ring.lock, flags); + + /* Assign the common bug type if no entries were found. */ + if (!info->bug_type) + info->bug_type = get_common_bug_type(info); +} diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index 77f13f391b57..a3afaf2ad1b1 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -42,7 +42,10 @@ void __init kasan_init_sw_tags(void) for_each_possible_cpu(cpu) per_cpu(prng_state, cpu) = (u32)get_cycles(); - pr_info("KernelAddressSanitizer initialized (sw-tags)\n"); + kasan_init_tags(); + + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n", + kasan_stack_collection_enabled() ? "on" : "off"); } /* diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index 8f48b9502a17..67a222586846 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -6,9 +6,11 @@ * Copyright (c) 2020 Google, Inc. */ +#include <linux/atomic.h> #include <linux/init.h> #include <linux/kasan.h> #include <linux/kernel.h> +#include <linux/memblock.h> #include <linux/memory.h> #include <linux/mm.h> #include <linux/static_key.h> @@ -16,44 +18,127 @@ #include <linux/types.h> #include "kasan.h" +#include "../slab.h" -void kasan_set_free_info(struct kmem_cache *cache, - void *object, u8 tag) -{ - struct kasan_alloc_meta *alloc_meta; - u8 idx = 0; +#define KASAN_STACK_RING_SIZE_DEFAULT (32 << 10) + +enum kasan_arg_stacktrace { + KASAN_ARG_STACKTRACE_DEFAULT, + KASAN_ARG_STACKTRACE_OFF, + KASAN_ARG_STACKTRACE_ON, +}; + +static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; + +/* Whether to collect alloc/free stack traces. */ +DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); - alloc_meta = kasan_get_alloc_meta(cache, object); - if (!alloc_meta) - return; +/* Non-zero, as initial pointer values are 0. */ +#define STACK_RING_BUSY_PTR ((void *)1) + +struct kasan_stack_ring stack_ring = { + .lock = __RW_LOCK_UNLOCKED(stack_ring.lock) +}; + +/* kasan.stacktrace=off/on */ +static int __init early_kasan_flag_stacktrace(char *arg) +{ + if (!arg) + return -EINVAL; -#ifdef CONFIG_KASAN_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 + if (!strcmp(arg, "off")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF; + else if (!strcmp(arg, "on")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON; + else + return -EINVAL; - kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT); + return 0; } +early_param("kasan.stacktrace", early_kasan_flag_stacktrace); -struct kasan_track *kasan_get_free_track(struct kmem_cache *cache, - void *object, u8 tag) +/* kasan.stack_ring_size=<number of entries> */ +static int __init early_kasan_flag_stack_ring_size(char *arg) { - struct kasan_alloc_meta *alloc_meta; - int i = 0; + if (!arg) + return -EINVAL; - alloc_meta = kasan_get_alloc_meta(cache, object); - if (!alloc_meta) - return NULL; + return kstrtoul(arg, 0, &stack_ring.size); +} +early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size); + +void __init kasan_init_tags(void) +{ + switch (kasan_arg_stacktrace) { + case KASAN_ARG_STACKTRACE_DEFAULT: + /* Default is specified by kasan_flag_stacktrace definition. */ + break; + case KASAN_ARG_STACKTRACE_OFF: + static_branch_disable(&kasan_flag_stacktrace); + break; + case KASAN_ARG_STACKTRACE_ON: + static_branch_enable(&kasan_flag_stacktrace); + break; + } -#ifdef CONFIG_KASAN_TAGS_IDENTIFY - for (i = 0; i < KASAN_NR_FREE_STACKS; i++) { - if (alloc_meta->free_pointer_tag[i] == tag) - break; + if (kasan_stack_collection_enabled()) { + if (!stack_ring.size) + stack_ring.size = KASAN_STACK_RING_SIZE_DEFAULT; + stack_ring.entries = memblock_alloc( + sizeof(stack_ring.entries[0]) * stack_ring.size, + SMP_CACHE_BYTES); + if (WARN_ON(!stack_ring.entries)) + static_branch_disable(&kasan_flag_stacktrace); } - if (i == KASAN_NR_FREE_STACKS) - i = alloc_meta->free_track_idx; -#endif +} + +static void save_stack_info(struct kmem_cache *cache, void *object, + gfp_t gfp_flags, bool is_free) +{ + unsigned long flags; + depot_stack_handle_t stack; + u64 pos; + struct kasan_stack_ring_entry *entry; + void *old_ptr; + + stack = kasan_save_stack(gfp_flags, true); + + /* + * Prevent save_stack_info() from modifying stack ring + * when kasan_complete_mode_report_info() is walking it. + */ + read_lock_irqsave(&stack_ring.lock, flags); + +next: + pos = atomic64_fetch_add(1, &stack_ring.pos); + entry = &stack_ring.entries[pos % stack_ring.size]; + + /* Detect stack ring entry slots that are being written to. */ + old_ptr = READ_ONCE(entry->ptr); + if (old_ptr == STACK_RING_BUSY_PTR) + goto next; /* Busy slot. */ + if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR)) + goto next; /* Busy slot. */ + + WRITE_ONCE(entry->size, cache->object_size); + WRITE_ONCE(entry->pid, current->pid); + WRITE_ONCE(entry->stack, stack); + WRITE_ONCE(entry->is_free, is_free); + + /* + * Paired with smp_load_acquire() in kasan_complete_mode_report_info(). + */ + smp_store_release(&entry->ptr, (s64)object); - return &alloc_meta->free_track[i]; + read_unlock_irqrestore(&stack_ring.lock, flags); +} + +void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) +{ + save_stack_info(cache, object, flags, false); +} + +void kasan_save_free_info(struct kmem_cache *cache, void *object) +{ + save_stack_info(cache, object, GFP_NOWAIT, true); } |