From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- mm/kasan/Makefile | 56 ++ mm/kasan/common.c | 452 ++++++++++++ mm/kasan/generic.c | 525 ++++++++++++++ mm/kasan/hw_tags.c | 396 +++++++++++ mm/kasan/init.c | 504 ++++++++++++++ mm/kasan/kasan.h | 644 +++++++++++++++++ mm/kasan/kasan_test.c | 1581 ++++++++++++++++++++++++++++++++++++++++++ mm/kasan/kasan_test_module.c | 81 +++ mm/kasan/quarantine.c | 420 +++++++++++ mm/kasan/report.c | 662 ++++++++++++++++++ mm/kasan/report_generic.c | 399 +++++++++++ mm/kasan/report_hw_tags.c | 71 ++ mm/kasan/report_sw_tags.c | 95 +++ mm/kasan/report_tags.c | 116 ++++ mm/kasan/shadow.c | 650 +++++++++++++++++ mm/kasan/sw_tags.c | 176 +++++ mm/kasan/tags.c | 144 ++++ 17 files changed, 6972 insertions(+) create mode 100644 mm/kasan/Makefile create mode 100644 mm/kasan/common.c create mode 100644 mm/kasan/generic.c create mode 100644 mm/kasan/hw_tags.c create mode 100644 mm/kasan/init.c create mode 100644 mm/kasan/kasan.h create mode 100644 mm/kasan/kasan_test.c create mode 100644 mm/kasan/kasan_test_module.c create mode 100644 mm/kasan/quarantine.c create mode 100644 mm/kasan/report.c create mode 100644 mm/kasan/report_generic.c create mode 100644 mm/kasan/report_hw_tags.c create mode 100644 mm/kasan/report_sw_tags.c create mode 100644 mm/kasan/report_tags.c create mode 100644 mm/kasan/shadow.c create mode 100644 mm/kasan/sw_tags.c create mode 100644 mm/kasan/tags.c (limited to 'mm/kasan') diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile new file mode 100644 index 000000000..7634dd2a6 --- /dev/null +++ b/mm/kasan/Makefile @@ -0,0 +1,56 @@ +# SPDX-License-Identifier: GPL-2.0 +KASAN_SANITIZE := n +UBSAN_SANITIZE := n +KCOV_INSTRUMENT := n + +# Disable ftrace to avoid recursion. +CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_generic.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_quarantine.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report_generic.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report_hw_tags.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report_sw_tags.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_hw_tags.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_sw_tags.o = $(CC_FLAGS_FTRACE) + +# Function splitter causes unnecessary splits in __asan_load1/__asan_store1 +# see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 +CC_FLAGS_KASAN_RUNTIME := $(call cc-option, -fno-conserve-stack) +CC_FLAGS_KASAN_RUNTIME += -fno-stack-protector +# Disable branch tracing to avoid recursion. +CC_FLAGS_KASAN_RUNTIME += -DDISABLE_BRANCH_PROFILING + +CFLAGS_common.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_generic.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_init.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_quarantine.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_report_generic.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_report_hw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_report_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME) +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) $(call cc-disable-warning, vla) +ifndef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX +# If compiler instruments memintrinsics by prefixing them with __asan/__hwasan, +# we need to treat them normally (as builtins), otherwise the compiler won't +# recognize them as instrumentable. If it doesn't instrument them, we need to +# pass -fno-builtin, so the compiler doesn't inline them. +CFLAGS_KASAN_TEST += -fno-builtin +endif + +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 new file mode 100644 index 000000000..256930da5 --- /dev/null +++ b/mm/kasan/common.c @@ -0,0 +1,452 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains common KASAN code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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); +} + +void kasan_set_track(struct kasan_track *track, gfp_t flags) +{ + track->pid = current->pid; + track->stack = kasan_save_stack(flags, true); +} + +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) +void kasan_enable_current(void) +{ + current->kasan_depth++; +} +EXPORT_SYMBOL(kasan_enable_current); + +void kasan_disable_current(void) +{ + current->kasan_depth--; +} +EXPORT_SYMBOL(kasan_disable_current); + +#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ + +void __kasan_unpoison_range(const void *address, size_t size) +{ + kasan_unpoison(address, size, false); +} + +#ifdef CONFIG_KASAN_STACK +/* Unpoison the entire stack for a task. */ +void kasan_unpoison_task_stack(struct task_struct *task) +{ + void *base = task_stack_page(task); + + kasan_unpoison(base, THREAD_SIZE, false); +} + +/* Unpoison the stack for the current task beyond a watermark sp value. */ +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) +{ + /* + * Calculate the task stack base address. Avoid using 'current' + * because this function is called by early resume code which hasn't + * yet set up the percpu register (%gs). + */ + void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1)); + + kasan_unpoison(base, watermark - base, false); +} +#endif /* CONFIG_KASAN_STACK */ + +bool __kasan_unpoison_pages(struct page *page, unsigned int order, bool init) +{ + u8 tag; + unsigned long i; + + if (unlikely(PageHighMem(page))) + return false; + + if (!kasan_sample_page_alloc(order)) + return false; + + tag = kasan_random_tag(); + kasan_unpoison(set_tag(page_address(page), tag), + PAGE_SIZE << order, init); + for (i = 0; i < (1 << order); i++) + page_kasan_tag_set(page + i, tag); + + return true; +} + +void __kasan_poison_pages(struct page *page, unsigned int order, bool init) +{ + if (likely(!PageHighMem(page))) + kasan_poison(page_address(page), PAGE_SIZE << order, + KASAN_PAGE_FREE, init); +} + +void __kasan_poison_slab(struct slab *slab) +{ + struct page *page = slab_page(slab); + unsigned long i; + + for (i = 0; i < compound_nr(page); i++) + page_kasan_tag_reset(page + i); + kasan_poison(page_address(page), page_size(page), + KASAN_SLAB_REDZONE, false); +} + +void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object) +{ + kasan_unpoison(object, cache->object_size, false); +} + +void __kasan_poison_object_data(struct kmem_cache *cache, void *object) +{ + kasan_poison(object, round_up(cache->object_size, KASAN_GRANULE_SIZE), + KASAN_SLAB_REDZONE, false); +} + +/* + * This function assigns a tag to an object considering the following: + * 1. A cache might have a constructor, which might save a pointer to a slab + * object somewhere (e.g. in the object itself). We preassign a tag for + * each object in caches with constructors during slab creation and reuse + * the same tag each time a particular object is allocated. + * 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) +{ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + return 0xff; + + /* + * If the cache neither has a constructor nor has SLAB_TYPESAFE_BY_RCU + * set, assign a tag when the object is being allocated (init == false). + */ + 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 + * the already assigned tag. + */ + return init ? kasan_random_tag() : get_tag(object); +#endif +} + +void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, + const void *object) +{ + /* 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)); + + return (void *)object; +} + +static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object, + unsigned long ip, bool quarantine, bool init) +{ + void *tagged_object; + + if (!kasan_arch_is_ready()) + return false; + + 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)) { + 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 */ + if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) + return false; + + if (!kasan_byte_accessible(tagged_object)) { + kasan_report_invalid_free(tagged_object, ip, KASAN_REPORT_DOUBLE_FREE); + return true; + } + + 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); +} + +bool __kasan_slab_free(struct kmem_cache *cache, void *object, + unsigned long ip, bool init) +{ + return ____kasan_slab_free(cache, object, ip, true, init); +} + +static inline bool ____kasan_kfree_large(void *ptr, unsigned long ip) +{ + if (!kasan_arch_is_ready()) + return false; + + if (ptr != page_address(virt_to_head_page(ptr))) { + kasan_report_invalid_free(ptr, ip, KASAN_REPORT_INVALID_FREE); + return true; + } + + if (!kasan_byte_accessible(ptr)) { + kasan_report_invalid_free(ptr, ip, KASAN_REPORT_DOUBLE_FREE); + 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); +} + +void __kasan_slab_free_mempool(void *ptr, unsigned long ip) +{ + 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. + */ + 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_slab_free(slab->slab_cache, ptr, ip, false, false); + } +} + +void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, + void *object, gfp_t flags, bool init) +{ + u8 tag; + void *tagged_object; + + if (gfpflags_allow_blocking(flags)) + kasan_quarantine_reduce(); + + if (unlikely(object == NULL)) + return NULL; + + if (is_kfence_address(object)) + return (void *)object; + + /* + * Generate and assign random tag for tag-based modes. + * Tag is ignored in set_tag() for the generic mode. + */ + 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); + + return tagged_object; +} + +static inline void *____kasan_kmalloc(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 + * part of the redzone. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + kasan_poison_last_granule((void *)object, size); + + /* Poison the aligned part of the redzone. */ + redzone_start = round_up((unsigned long)(object + size), + KASAN_GRANULE_SIZE); + redzone_end = round_up((unsigned long)(object + cache->object_size), + KASAN_GRANULE_SIZE); + kasan_poison((void *)redzone_start, redzone_end - redzone_start, + KASAN_SLAB_REDZONE, false); + + /* + * Save alloc info (if possible) for kmalloc() allocations. + * This also rewrites the alloc info when called from kasan_krealloc(). + */ + 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); +} +EXPORT_SYMBOL(__kasan_kmalloc); + +void * __must_check __kasan_kmalloc_large(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 + * part of the redzone. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + 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_end = (unsigned long)ptr + page_size(virt_to_page(ptr)); + kasan_poison((void *)redzone_start, redzone_end - redzone_start, + KASAN_PAGE_REDZONE, false); + + return (void *)ptr; +} + +void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags) +{ + struct slab *slab; + + if (unlikely(object == ZERO_SIZE_PTR)) + return (void *)object; + + /* + * Unpoison the object's data. + * Part of it might already have been unpoisoned, but it's unknown + * how big that part is. + */ + kasan_unpoison(object, size, false); + + slab = virt_to_slab(object); + + /* Piggy-back on kmalloc() instrumentation to poison the redzone. */ + if (unlikely(!slab)) + return __kasan_kmalloc_large(object, size, flags); + else + return ____kasan_kmalloc(slab->slab_cache, object, size, flags); +} + +bool __kasan_check_byte(const void *address, unsigned long ip) +{ + if (!kasan_byte_accessible(address)) { + kasan_report(address, 1, false, ip); + return false; + } + return true; +} diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c new file mode 100644 index 000000000..4d837ab83 --- /dev/null +++ b/mm/kasan/generic.c @@ -0,0 +1,525 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains core generic KASAN code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kasan.h" +#include "../slab.h" + +/* + * All functions below always inlined so compiler could + * perform better optimizations in each of __asan_loadX/__assn_storeX + * depending on memory access size X. + */ + +static __always_inline bool memory_is_poisoned_1(const void *addr) +{ + s8 shadow_value = *(s8 *)kasan_mem_to_shadow(addr); + + if (unlikely(shadow_value)) { + s8 last_accessible_byte = (unsigned long)addr & KASAN_GRANULE_MASK; + return unlikely(last_accessible_byte >= shadow_value); + } + + return false; +} + +static __always_inline bool memory_is_poisoned_2_4_8(const void *addr, + unsigned long size) +{ + u8 *shadow_addr = (u8 *)kasan_mem_to_shadow(addr); + + /* + * Access crosses 8(shadow size)-byte boundary. Such access maps + * into 2 shadow bytes, so we need to check them both. + */ + if (unlikely((((unsigned long)addr + size - 1) & KASAN_GRANULE_MASK) < size - 1)) + return *shadow_addr || memory_is_poisoned_1(addr + size - 1); + + return memory_is_poisoned_1(addr + size - 1); +} + +static __always_inline bool memory_is_poisoned_16(const void *addr) +{ + u16 *shadow_addr = (u16 *)kasan_mem_to_shadow(addr); + + /* Unaligned 16-bytes access maps into 3 shadow bytes. */ + if (unlikely(!IS_ALIGNED((unsigned long)addr, KASAN_GRANULE_SIZE))) + return *shadow_addr || memory_is_poisoned_1(addr + 15); + + return *shadow_addr; +} + +static __always_inline unsigned long bytes_is_nonzero(const u8 *start, + size_t size) +{ + while (size) { + if (unlikely(*start)) + return (unsigned long)start; + start++; + size--; + } + + return 0; +} + +static __always_inline unsigned long memory_is_nonzero(const void *start, + const void *end) +{ + unsigned int words; + unsigned long ret; + unsigned int prefix = (unsigned long)start % 8; + + if (end - start <= 16) + return bytes_is_nonzero(start, end - start); + + if (prefix) { + prefix = 8 - prefix; + ret = bytes_is_nonzero(start, prefix); + if (unlikely(ret)) + return ret; + start += prefix; + } + + words = (end - start) / 8; + while (words) { + if (unlikely(*(u64 *)start)) + return bytes_is_nonzero(start, 8); + start += 8; + words--; + } + + return bytes_is_nonzero(start, (end - start) % 8); +} + +static __always_inline bool memory_is_poisoned_n(const void *addr, size_t size) +{ + unsigned long ret; + + ret = memory_is_nonzero(kasan_mem_to_shadow(addr), + kasan_mem_to_shadow(addr + size - 1) + 1); + + if (unlikely(ret)) { + const void *last_byte = addr + size - 1; + s8 *last_shadow = (s8 *)kasan_mem_to_shadow(last_byte); + s8 last_accessible_byte = (unsigned long)last_byte & KASAN_GRANULE_MASK; + + if (unlikely(ret != (unsigned long)last_shadow || + last_accessible_byte >= *last_shadow)) + return true; + } + return false; +} + +static __always_inline bool memory_is_poisoned(const void *addr, size_t size) +{ + if (__builtin_constant_p(size)) { + switch (size) { + case 1: + return memory_is_poisoned_1(addr); + case 2: + case 4: + case 8: + return memory_is_poisoned_2_4_8(addr, size); + case 16: + return memory_is_poisoned_16(addr); + default: + BUILD_BUG(); + } + } + + return memory_is_poisoned_n(addr, size); +} + +static __always_inline bool check_region_inline(const void *addr, + size_t size, bool write, + unsigned long ret_ip) +{ + if (!kasan_arch_is_ready()) + return true; + + if (unlikely(size == 0)) + return true; + + if (unlikely(addr + size < addr)) + return !kasan_report(addr, size, write, ret_ip); + + if (unlikely(!addr_has_metadata(addr))) + return !kasan_report(addr, size, write, ret_ip); + + if (likely(!memory_is_poisoned(addr, size))) + return true; + + return !kasan_report(addr, size, write, ret_ip); +} + +bool kasan_check_range(const void *addr, size_t size, bool write, + unsigned long ret_ip) +{ + return check_region_inline(addr, size, write, ret_ip); +} + +bool kasan_byte_accessible(const void *addr) +{ + s8 shadow_byte; + + if (!kasan_arch_is_ready()) + return true; + + shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr)); + + return shadow_byte >= 0 && shadow_byte < KASAN_GRANULE_SIZE; +} + +void kasan_cache_shrink(struct kmem_cache *cache) +{ + kasan_quarantine_remove_cache(cache); +} + +void kasan_cache_shutdown(struct kmem_cache *cache) +{ + if (!__kmem_cache_empty(cache)) + kasan_quarantine_remove_cache(cache); +} + +static void register_global(struct kasan_global *global) +{ + size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE); + + kasan_unpoison(global->beg, global->size, false); + + kasan_poison(global->beg + aligned_size, + global->size_with_redzone - aligned_size, + KASAN_GLOBAL_REDZONE, false); +} + +void __asan_register_globals(void *ptr, ssize_t size) +{ + int i; + struct kasan_global *globals = ptr; + + for (i = 0; i < size; i++) + register_global(&globals[i]); +} +EXPORT_SYMBOL(__asan_register_globals); + +void __asan_unregister_globals(void *ptr, ssize_t size) +{ +} +EXPORT_SYMBOL(__asan_unregister_globals); + +#define DEFINE_ASAN_LOAD_STORE(size) \ + void __asan_load##size(void *addr) \ + { \ + check_region_inline(addr, size, false, _RET_IP_); \ + } \ + EXPORT_SYMBOL(__asan_load##size); \ + __alias(__asan_load##size) \ + void __asan_load##size##_noabort(void *); \ + EXPORT_SYMBOL(__asan_load##size##_noabort); \ + void __asan_store##size(void *addr) \ + { \ + check_region_inline(addr, size, true, _RET_IP_); \ + } \ + EXPORT_SYMBOL(__asan_store##size); \ + __alias(__asan_store##size) \ + void __asan_store##size##_noabort(void *); \ + EXPORT_SYMBOL(__asan_store##size##_noabort) + +DEFINE_ASAN_LOAD_STORE(1); +DEFINE_ASAN_LOAD_STORE(2); +DEFINE_ASAN_LOAD_STORE(4); +DEFINE_ASAN_LOAD_STORE(8); +DEFINE_ASAN_LOAD_STORE(16); + +void __asan_loadN(void *addr, ssize_t size) +{ + kasan_check_range(addr, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__asan_loadN); + +__alias(__asan_loadN) +void __asan_loadN_noabort(void *, ssize_t); +EXPORT_SYMBOL(__asan_loadN_noabort); + +void __asan_storeN(void *addr, ssize_t size) +{ + kasan_check_range(addr, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__asan_storeN); + +__alias(__asan_storeN) +void __asan_storeN_noabort(void *, ssize_t); +EXPORT_SYMBOL(__asan_storeN_noabort); + +/* to shut up compiler complaints */ +void __asan_handle_no_return(void) {} +EXPORT_SYMBOL(__asan_handle_no_return); + +/* Emitted by compiler to poison alloca()ed objects. */ +void __asan_alloca_poison(void *addr, ssize_t size) +{ + size_t rounded_up_size = round_up(size, KASAN_GRANULE_SIZE); + size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) - + rounded_up_size; + size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE); + + const void *left_redzone = (const void *)(addr - + KASAN_ALLOCA_REDZONE_SIZE); + const void *right_redzone = (const void *)(addr + rounded_up_size); + + WARN_ON(!IS_ALIGNED((unsigned long)addr, KASAN_ALLOCA_REDZONE_SIZE)); + + kasan_unpoison((const void *)(addr + rounded_down_size), + size - rounded_down_size, false); + kasan_poison(left_redzone, KASAN_ALLOCA_REDZONE_SIZE, + KASAN_ALLOCA_LEFT, false); + kasan_poison(right_redzone, padding_size + KASAN_ALLOCA_REDZONE_SIZE, + KASAN_ALLOCA_RIGHT, false); +} +EXPORT_SYMBOL(__asan_alloca_poison); + +/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */ +void __asan_allocas_unpoison(void *stack_top, ssize_t stack_bottom) +{ + if (unlikely(!stack_top || stack_top > (void *)stack_bottom)) + return; + + kasan_unpoison(stack_top, (void *)stack_bottom - stack_top, false); +} +EXPORT_SYMBOL(__asan_allocas_unpoison); + +/* Emitted by the compiler to [un]poison local variables. */ +#define DEFINE_ASAN_SET_SHADOW(byte) \ + void __asan_set_shadow_##byte(const void *addr, ssize_t size) \ + { \ + __memset((void *)addr, 0x##byte, size); \ + } \ + EXPORT_SYMBOL(__asan_set_shadow_##byte) + +DEFINE_ASAN_SET_SHADOW(00); +DEFINE_ASAN_SET_SHADOW(f1); +DEFINE_ASAN_SET_SHADOW(f2); +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, bool in_object) +{ + struct kasan_cache *info = &cache->kasan_info; + + if (!kasan_requires_meta()) + return 0; + + if (in_object) + return (info->free_meta_offset ? + 0 : sizeof(struct kasan_free_meta)); + else + return (info->alloc_meta_offset ? + sizeof(struct kasan_alloc_meta) : 0) + + ((info->free_meta_offset && + 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); + struct kmem_cache *cache; + struct kasan_alloc_meta *alloc_meta; + void *object; + + if (is_kfence_address(addr) || !slab) + return; + + cache = slab->slab_cache; + object = nearest_obj(cache, slab, addr); + alloc_meta = kasan_get_alloc_meta(cache, object); + if (!alloc_meta) + return; + + alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0]; + alloc_meta->aux_stack[0] = kasan_save_stack(0, can_alloc); +} + +void kasan_record_aux_stack(void *addr) +{ + return __kasan_record_aux_stack(addr, true); +} + +void kasan_record_aux_stack_noalloc(void *addr) +{ + return __kasan_record_aux_stack(addr, false); +} + +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; + + free_meta = kasan_get_free_meta(cache, object); + if (!free_meta) + return; + + kasan_set_track(&free_meta->free_track, 0); + /* The object was freed and has free track set. */ + *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREETRACK; +} diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c new file mode 100644 index 000000000..06141bbc1 --- /dev/null +++ b/mm/kasan/hw_tags.c @@ -0,0 +1,396 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains core hardware tag-based KASAN code. + * + * Copyright (c) 2020 Google, Inc. + * Author: Andrey Konovalov + */ + +#define pr_fmt(fmt) "kasan: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kasan.h" + +enum kasan_arg { + KASAN_ARG_DEFAULT, + KASAN_ARG_OFF, + KASAN_ARG_ON, +}; + +enum kasan_arg_mode { + KASAN_ARG_MODE_DEFAULT, + KASAN_ARG_MODE_SYNC, + KASAN_ARG_MODE_ASYNC, + KASAN_ARG_MODE_ASYMM, +}; + +enum kasan_arg_vmalloc { + KASAN_ARG_VMALLOC_DEFAULT, + KASAN_ARG_VMALLOC_OFF, + KASAN_ARG_VMALLOC_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; + +/* + * Whether KASAN is enabled at all. + * The value remains false until KASAN is initialized by kasan_init_hw_tags(). + */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); +EXPORT_SYMBOL(kasan_flag_enabled); + +/* + * Whether the selected mode is synchronous, asynchronous, or asymmetric. + * Defaults to KASAN_MODE_SYNC. + */ +enum kasan_mode kasan_mode __ro_after_init; +EXPORT_SYMBOL_GPL(kasan_mode); + +/* Whether to enable vmalloc tagging. */ +DEFINE_STATIC_KEY_TRUE(kasan_flag_vmalloc); + +#define PAGE_ALLOC_SAMPLE_DEFAULT 1 +#define PAGE_ALLOC_SAMPLE_ORDER_DEFAULT 3 + +/* + * Sampling interval of page_alloc allocation (un)poisoning. + * Defaults to no sampling. + */ +unsigned long kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT; + +/* + * Minimum order of page_alloc allocations to be affected by sampling. + * The default value is chosen to match both + * PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER. + */ +unsigned int kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT; + +DEFINE_PER_CPU(long, kasan_page_alloc_skip); + +/* kasan=off/on */ +static int __init early_kasan_flag(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg = KASAN_ARG_OFF; + else if (!strcmp(arg, "on")) + kasan_arg = KASAN_ARG_ON; + else + return -EINVAL; + + return 0; +} +early_param("kasan", early_kasan_flag); + +/* kasan.mode=sync/async/asymm */ +static int __init early_kasan_mode(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "sync")) + kasan_arg_mode = KASAN_ARG_MODE_SYNC; + else if (!strcmp(arg, "async")) + kasan_arg_mode = KASAN_ARG_MODE_ASYNC; + else if (!strcmp(arg, "asymm")) + kasan_arg_mode = KASAN_ARG_MODE_ASYMM; + else + return -EINVAL; + + return 0; +} +early_param("kasan.mode", early_kasan_mode); + +/* kasan.vmalloc=off/on */ +static int __init early_kasan_flag_vmalloc(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg_vmalloc = KASAN_ARG_VMALLOC_OFF; + else if (!strcmp(arg, "on")) + kasan_arg_vmalloc = KASAN_ARG_VMALLOC_ON; + else + return -EINVAL; + + return 0; +} +early_param("kasan.vmalloc", early_kasan_flag_vmalloc); + +static inline const char *kasan_mode_info(void) +{ + if (kasan_mode == KASAN_MODE_ASYNC) + return "async"; + else if (kasan_mode == KASAN_MODE_ASYMM) + return "asymm"; + else + return "sync"; +} + +/* kasan.page_alloc.sample= */ +static int __init early_kasan_flag_page_alloc_sample(char *arg) +{ + int rv; + + if (!arg) + return -EINVAL; + + rv = kstrtoul(arg, 0, &kasan_page_alloc_sample); + if (rv) + return rv; + + if (!kasan_page_alloc_sample || kasan_page_alloc_sample > LONG_MAX) { + kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT; + return -EINVAL; + } + + return 0; +} +early_param("kasan.page_alloc.sample", early_kasan_flag_page_alloc_sample); + +/* kasan.page_alloc.sample.order= */ +static int __init early_kasan_flag_page_alloc_sample_order(char *arg) +{ + int rv; + + if (!arg) + return -EINVAL; + + rv = kstrtouint(arg, 0, &kasan_page_alloc_sample_order); + if (rv) + return rv; + + if (kasan_page_alloc_sample_order > INT_MAX) { + kasan_page_alloc_sample_order = PAGE_ALLOC_SAMPLE_ORDER_DEFAULT; + return -EINVAL; + } + + return 0; +} +early_param("kasan.page_alloc.sample.order", early_kasan_flag_page_alloc_sample_order); + +/* + * kasan_init_hw_tags_cpu() is called for each CPU. + * Not marked as __init as a CPU can be hot-plugged after boot. + */ +void kasan_init_hw_tags_cpu(void) +{ + /* + * There's no need to check that the hardware is MTE-capable here, + * as this function is only called for MTE-capable hardware. + */ + + /* + * If KASAN is disabled via command line, don't initialize it. + * When this function is called, kasan_flag_enabled is not yet + * set by kasan_init_hw_tags(). Thus, check kasan_arg instead. + */ + if (kasan_arg == KASAN_ARG_OFF) + return; + + /* + * Enable async or asymm modes only when explicitly requested + * through the command line. + */ + kasan_enable_hw_tags(); +} + +/* kasan_init_hw_tags() is called once on boot CPU. */ +void __init kasan_init_hw_tags(void) +{ + /* If hardware doesn't support MTE, don't initialize KASAN. */ + if (!system_supports_mte()) + return; + + /* If KASAN is disabled via command line, don't initialize it. */ + if (kasan_arg == KASAN_ARG_OFF) + return; + + switch (kasan_arg_mode) { + case KASAN_ARG_MODE_DEFAULT: + /* Default is specified by kasan_mode definition. */ + break; + case KASAN_ARG_MODE_SYNC: + kasan_mode = KASAN_MODE_SYNC; + break; + case KASAN_ARG_MODE_ASYNC: + kasan_mode = KASAN_MODE_ASYNC; + break; + case KASAN_ARG_MODE_ASYMM: + kasan_mode = KASAN_MODE_ASYMM; + break; + } + + switch (kasan_arg_vmalloc) { + case KASAN_ARG_VMALLOC_DEFAULT: + /* Default is specified by kasan_flag_vmalloc definition. */ + break; + case KASAN_ARG_VMALLOC_OFF: + static_branch_disable(&kasan_flag_vmalloc); + break; + case KASAN_ARG_VMALLOC_ON: + static_branch_enable(&kasan_flag_vmalloc); + break; + } + + kasan_init_tags(); + + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); + + pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, vmalloc=%s, stacktrace=%s)\n", + kasan_mode_info(), + kasan_vmalloc_enabled() ? "on" : "off", + kasan_stack_collection_enabled() ? "on" : "off"); +} + +#ifdef CONFIG_KASAN_VMALLOC + +static void unpoison_vmalloc_pages(const void *addr, u8 tag) +{ + struct vm_struct *area; + int i; + + /* + * As hardware tag-based KASAN only tags VM_ALLOC vmalloc allocations + * (see the comment in __kasan_unpoison_vmalloc), all of the pages + * should belong to a single area. + */ + area = find_vm_area((void *)addr); + if (WARN_ON(!area)) + return; + + for (i = 0; i < area->nr_pages; i++) { + struct page *page = area->pages[i]; + + page_kasan_tag_set(page, tag); + } +} + +static void init_vmalloc_pages(const void *start, unsigned long size) +{ + const void *addr; + + for (addr = start; addr < start + size; addr += PAGE_SIZE) { + struct page *page = vmalloc_to_page(addr); + + clear_highpage_kasan_tagged(page); + } +} + +void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, + kasan_vmalloc_flags_t flags) +{ + u8 tag; + unsigned long redzone_start, redzone_size; + + if (!kasan_vmalloc_enabled()) { + if (flags & KASAN_VMALLOC_INIT) + init_vmalloc_pages(start, size); + return (void *)start; + } + + /* + * Don't tag non-VM_ALLOC mappings, as: + * + * 1. Unlike the software KASAN modes, hardware tag-based KASAN only + * supports tagging physical memory. Therefore, it can only tag a + * single mapping of normal physical pages. + * 2. Hardware tag-based KASAN can only tag memory mapped with special + * mapping protection bits, see arch_vmap_pgprot_tagged(). + * As non-VM_ALLOC mappings can be mapped outside of vmalloc code, + * providing these bits would require tracking all non-VM_ALLOC + * mappers. + * + * Thus, for VM_ALLOC mappings, hardware tag-based KASAN only tags + * the first virtual mapping, which is created by vmalloc(). + * Tagging the page_alloc memory backing that vmalloc() allocation is + * skipped, see ___GFP_SKIP_KASAN. + * + * For non-VM_ALLOC allocations, page_alloc memory is tagged as usual. + */ + if (!(flags & KASAN_VMALLOC_VM_ALLOC)) { + WARN_ON(flags & KASAN_VMALLOC_INIT); + return (void *)start; + } + + /* + * Don't tag executable memory. + * The kernel doesn't tolerate having the PC register tagged. + */ + if (!(flags & KASAN_VMALLOC_PROT_NORMAL)) { + WARN_ON(flags & KASAN_VMALLOC_INIT); + return (void *)start; + } + + tag = kasan_random_tag(); + start = set_tag(start, tag); + + /* Unpoison and initialize memory up to size. */ + kasan_unpoison(start, size, flags & KASAN_VMALLOC_INIT); + + /* + * Explicitly poison and initialize the in-page vmalloc() redzone. + * Unlike software KASAN modes, hardware tag-based KASAN doesn't + * unpoison memory when populating shadow for vmalloc() space. + */ + redzone_start = round_up((unsigned long)start + size, + KASAN_GRANULE_SIZE); + redzone_size = round_up(redzone_start, PAGE_SIZE) - redzone_start; + kasan_poison((void *)redzone_start, redzone_size, KASAN_TAG_INVALID, + flags & KASAN_VMALLOC_INIT); + + /* + * Set per-page tag flags to allow accessing physical memory for the + * vmalloc() mapping through page_address(vmalloc_to_page()). + */ + unpoison_vmalloc_pages(start, tag); + + return (void *)start; +} + +void __kasan_poison_vmalloc(const void *start, unsigned long size) +{ + /* + * No tagging here. + * The physical pages backing the vmalloc() allocation are poisoned + * through the usual page_alloc paths. + */ +} + +#endif + +void kasan_enable_hw_tags(void) +{ + if (kasan_arg_mode == KASAN_ARG_MODE_ASYNC) + hw_enable_tag_checks_async(); + else if (kasan_arg_mode == KASAN_ARG_MODE_ASYMM) + hw_enable_tag_checks_asymm(); + else + hw_enable_tag_checks_sync(); +} + +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) + +EXPORT_SYMBOL_GPL(kasan_enable_hw_tags); + +void kasan_force_async_fault(void) +{ + hw_force_async_tag_fault(); +} +EXPORT_SYMBOL_GPL(kasan_force_async_fault); + +#endif diff --git a/mm/kasan/init.c b/mm/kasan/init.c new file mode 100644 index 000000000..89895f38f --- /dev/null +++ b/mm/kasan/init.c @@ -0,0 +1,504 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains KASAN shadow initialization code. + * + * Copyright (c) 2015 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "kasan.h" + +/* + * This page serves two purposes: + * - It used as early shadow memory. The entire shadow region populated + * with this page, before we will be able to setup normal shadow memory. + * - Latter it reused it as zero shadow to cover large ranges of memory + * that allowed to access, but not handled by kasan (vmalloc/vmemmap ...). + */ +unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss; + +#if CONFIG_PGTABLE_LEVELS > 4 +p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss; +static inline bool kasan_p4d_table(pgd_t pgd) +{ + return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d)); +} +#else +static inline bool kasan_p4d_table(pgd_t pgd) +{ + return false; +} +#endif +#if CONFIG_PGTABLE_LEVELS > 3 +pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss; +static inline bool kasan_pud_table(p4d_t p4d) +{ + return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud)); +} +#else +static inline bool kasan_pud_table(p4d_t p4d) +{ + return false; +} +#endif +#if CONFIG_PGTABLE_LEVELS > 2 +pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss; +static inline bool kasan_pmd_table(pud_t pud) +{ + return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd)); +} +#else +static inline bool kasan_pmd_table(pud_t pud) +{ + return false; +} +#endif +pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS] + __page_aligned_bss; + +static inline bool kasan_pte_table(pmd_t pmd) +{ + return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte)); +} + +static inline bool kasan_early_shadow_page_entry(pte_t pte) +{ + return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page)); +} + +static __init void *early_alloc(size_t size, int node) +{ + void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), + MEMBLOCK_ALLOC_ACCESSIBLE, node); + + if (!ptr) + panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n", + __func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS)); + + return ptr; +} + +static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr, + unsigned long end) +{ + pte_t *pte = pte_offset_kernel(pmd, addr); + pte_t zero_pte; + + zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)), + PAGE_KERNEL); + zero_pte = pte_wrprotect(zero_pte); + + while (addr + PAGE_SIZE <= end) { + set_pte_at(&init_mm, addr, pte, zero_pte); + addr += PAGE_SIZE; + pte = pte_offset_kernel(pmd, addr); + } +} + +static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, + unsigned long end) +{ + pmd_t *pmd = pmd_offset(pud, addr); + unsigned long next; + + do { + next = pmd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { + pmd_populate_kernel(&init_mm, pmd, + lm_alias(kasan_early_shadow_pte)); + continue; + } + + if (pmd_none(*pmd)) { + pte_t *p; + + if (slab_is_available()) + p = pte_alloc_one_kernel(&init_mm); + else + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); + if (!p) + return -ENOMEM; + + pmd_populate_kernel(&init_mm, pmd, p); + } + zero_pte_populate(pmd, addr, next); + } while (pmd++, addr = next, addr != end); + + return 0; +} + +void __weak __meminit pmd_init(void *addr) +{ +} + +static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, + unsigned long end) +{ + pud_t *pud = pud_offset(p4d, addr); + unsigned long next; + + do { + next = pud_addr_end(addr, end); + if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { + pmd_t *pmd; + + pud_populate(&init_mm, pud, + lm_alias(kasan_early_shadow_pmd)); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, + lm_alias(kasan_early_shadow_pte)); + continue; + } + + if (pud_none(*pud)) { + pmd_t *p; + + if (slab_is_available()) { + p = pmd_alloc(&init_mm, pud, addr); + if (!p) + return -ENOMEM; + } else { + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); + pmd_init(p); + pud_populate(&init_mm, pud, p); + } + } + zero_pmd_populate(pud, addr, next); + } while (pud++, addr = next, addr != end); + + return 0; +} + +void __weak __meminit pud_init(void *addr) +{ +} + +static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, + unsigned long end) +{ + p4d_t *p4d = p4d_offset(pgd, addr); + unsigned long next; + + do { + next = p4d_addr_end(addr, end); + if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) { + pud_t *pud; + pmd_t *pmd; + + p4d_populate(&init_mm, p4d, + lm_alias(kasan_early_shadow_pud)); + pud = pud_offset(p4d, addr); + pud_populate(&init_mm, pud, + lm_alias(kasan_early_shadow_pmd)); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, + lm_alias(kasan_early_shadow_pte)); + continue; + } + + if (p4d_none(*p4d)) { + pud_t *p; + + if (slab_is_available()) { + p = pud_alloc(&init_mm, p4d, addr); + if (!p) + return -ENOMEM; + } else { + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); + pud_init(p); + p4d_populate(&init_mm, p4d, p); + } + } + zero_pud_populate(p4d, addr, next); + } while (p4d++, addr = next, addr != end); + + return 0; +} + +/** + * kasan_populate_early_shadow - populate shadow memory region with + * kasan_early_shadow_page + * @shadow_start: start of the memory range to populate + * @shadow_end: end of the memory range to populate + */ +int __ref kasan_populate_early_shadow(const void *shadow_start, + const void *shadow_end) +{ + unsigned long addr = (unsigned long)shadow_start; + unsigned long end = (unsigned long)shadow_end; + pgd_t *pgd = pgd_offset_k(addr); + unsigned long next; + + do { + next = pgd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + + /* + * kasan_early_shadow_pud should be populated with pmds + * at this moment. + * [pud,pmd]_populate*() below needed only for + * 3,2 - level page tables where we don't have + * puds,pmds, so pgd_populate(), pud_populate() + * is noops. + */ + pgd_populate(&init_mm, pgd, + lm_alias(kasan_early_shadow_p4d)); + p4d = p4d_offset(pgd, addr); + p4d_populate(&init_mm, p4d, + lm_alias(kasan_early_shadow_pud)); + pud = pud_offset(p4d, addr); + pud_populate(&init_mm, pud, + lm_alias(kasan_early_shadow_pmd)); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, + lm_alias(kasan_early_shadow_pte)); + continue; + } + + if (pgd_none(*pgd)) { + p4d_t *p; + + if (slab_is_available()) { + p = p4d_alloc(&init_mm, pgd, addr); + if (!p) + return -ENOMEM; + } else { + pgd_populate(&init_mm, pgd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + } + zero_p4d_populate(pgd, addr, next); + } while (pgd++, addr = next, addr != end); + + return 0; +} + +static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) +{ + pte_t *pte; + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) { + pte = pte_start + i; + if (!pte_none(ptep_get(pte))) + return; + } + + pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); + pmd_clear(pmd); +} + +static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) +{ + pmd_t *pmd; + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) { + pmd = pmd_start + i; + if (!pmd_none(*pmd)) + return; + } + + pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); + pud_clear(pud); +} + +static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) +{ + pud_t *pud; + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) { + pud = pud_start + i; + if (!pud_none(*pud)) + return; + } + + pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); + p4d_clear(p4d); +} + +static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) +{ + p4d_t *p4d; + int i; + + for (i = 0; i < PTRS_PER_P4D; i++) { + p4d = p4d_start + i; + if (!p4d_none(*p4d)) + return; + } + + p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); + pgd_clear(pgd); +} + +static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, + unsigned long end) +{ + unsigned long next; + pte_t ptent; + + for (; addr < end; addr = next, pte++) { + next = (addr + PAGE_SIZE) & PAGE_MASK; + if (next > end) + next = end; + + ptent = ptep_get(pte); + + if (!pte_present(ptent)) + continue; + + if (WARN_ON(!kasan_early_shadow_page_entry(ptent))) + continue; + pte_clear(&init_mm, addr, pte); + } +} + +static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, pmd++) { + pte_t *pte; + + next = pmd_addr_end(addr, end); + + if (!pmd_present(*pmd)) + continue; + + if (kasan_pte_table(*pmd)) { + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE)) { + pmd_clear(pmd); + continue; + } + } + pte = pte_offset_kernel(pmd, addr); + kasan_remove_pte_table(pte, addr, next); + kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); + } +} + +static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, pud++) { + pmd_t *pmd, *pmd_base; + + next = pud_addr_end(addr, end); + + if (!pud_present(*pud)) + continue; + + if (kasan_pmd_table(*pud)) { + if (IS_ALIGNED(addr, PUD_SIZE) && + IS_ALIGNED(next, PUD_SIZE)) { + pud_clear(pud); + continue; + } + } + pmd = pmd_offset(pud, addr); + pmd_base = pmd_offset(pud, 0); + kasan_remove_pmd_table(pmd, addr, next); + kasan_free_pmd(pmd_base, pud); + } +} + +static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, p4d++) { + pud_t *pud; + + next = p4d_addr_end(addr, end); + + if (!p4d_present(*p4d)) + continue; + + if (kasan_pud_table(*p4d)) { + if (IS_ALIGNED(addr, P4D_SIZE) && + IS_ALIGNED(next, P4D_SIZE)) { + p4d_clear(p4d); + continue; + } + } + pud = pud_offset(p4d, addr); + kasan_remove_pud_table(pud, addr, next); + kasan_free_pud(pud_offset(p4d, 0), p4d); + } +} + +void kasan_remove_zero_shadow(void *start, unsigned long size) +{ + unsigned long addr, end, next; + pgd_t *pgd; + + addr = (unsigned long)kasan_mem_to_shadow(start); + end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); + + if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) || + WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE)) + return; + + for (; addr < end; addr = next) { + p4d_t *p4d; + + next = pgd_addr_end(addr, end); + + pgd = pgd_offset_k(addr); + if (!pgd_present(*pgd)) + continue; + + if (kasan_p4d_table(*pgd)) { + if (IS_ALIGNED(addr, PGDIR_SIZE) && + IS_ALIGNED(next, PGDIR_SIZE)) { + pgd_clear(pgd); + continue; + } + } + + p4d = p4d_offset(pgd, addr); + kasan_remove_p4d_table(p4d, addr, next); + kasan_free_p4d(p4d_offset(pgd, 0), pgd); + } +} + +int kasan_add_zero_shadow(void *start, unsigned long size) +{ + int ret; + void *shadow_start, *shadow_end; + + shadow_start = kasan_mem_to_shadow(start); + shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); + + if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) || + WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE)) + return -EINVAL; + + ret = kasan_populate_early_shadow(shadow_start, shadow_end); + if (ret) + kasan_remove_zero_shadow(start, size); + return ret; +} diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h new file mode 100644 index 000000000..d37831b85 --- /dev/null +++ b/mm/kasan/kasan.h @@ -0,0 +1,644 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __MM_KASAN_KASAN_H +#define __MM_KASAN_KASAN_H + +#include +#include +#include +#include +#include + +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) + +#include + +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); + +enum kasan_mode { + KASAN_MODE_SYNC, + KASAN_MODE_ASYNC, + KASAN_MODE_ASYMM, +}; + +extern enum kasan_mode kasan_mode __ro_after_init; + +extern unsigned long kasan_page_alloc_sample; +extern unsigned int kasan_page_alloc_sample_order; +DECLARE_PER_CPU(long, kasan_page_alloc_skip); + +static inline bool kasan_vmalloc_enabled(void) +{ + return static_branch_likely(&kasan_flag_vmalloc); +} + +static inline bool kasan_async_fault_possible(void) +{ + return kasan_mode == KASAN_MODE_ASYNC || kasan_mode == KASAN_MODE_ASYMM; +} + +static inline bool kasan_sync_fault_possible(void) +{ + return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM; +} + +static inline bool kasan_sample_page_alloc(unsigned int order) +{ + /* Fast-path for when sampling is disabled. */ + if (kasan_page_alloc_sample == 1) + return true; + + if (order < kasan_page_alloc_sample_order) + return true; + + if (this_cpu_dec_return(kasan_page_alloc_skip) < 0) { + this_cpu_write(kasan_page_alloc_skip, + kasan_page_alloc_sample - 1); + return true; + } + + return false; +} + +#else /* CONFIG_KASAN_HW_TAGS */ + +static inline bool kasan_async_fault_possible(void) +{ + return false; +} + +static inline bool kasan_sync_fault_possible(void) +{ + return true; +} + +static inline bool kasan_sample_page_alloc(unsigned int order) +{ + return true; +} + +#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) +#else +#include +#define KASAN_GRANULE_SIZE MTE_GRANULE_SIZE +#endif + +#define KASAN_GRANULE_MASK (KASAN_GRANULE_SIZE - 1) + +#define KASAN_MEMORY_PER_SHADOW_PAGE (KASAN_GRANULE_SIZE << PAGE_SHIFT) + +#ifdef CONFIG_KASAN_GENERIC +#define KASAN_PAGE_FREE 0xFF /* freed page */ +#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocation */ +#define KASAN_SLAB_REDZONE 0xFC /* redzone for slab object */ +#define KASAN_SLAB_FREE 0xFB /* freed slab object */ +#define KASAN_VMALLOC_INVALID 0xF8 /* inaccessible space in vmap area */ +#else +#define KASAN_PAGE_FREE KASAN_TAG_INVALID +#define KASAN_PAGE_REDZONE KASAN_TAG_INVALID +#define KASAN_SLAB_REDZONE KASAN_TAG_INVALID +#define KASAN_SLAB_FREE KASAN_TAG_INVALID +#define KASAN_VMALLOC_INVALID KASAN_TAG_INVALID /* only used for SW_TAGS */ +#endif + +#ifdef CONFIG_KASAN_GENERIC + +#define KASAN_SLAB_FREETRACK 0xFA /* freed slab object with free track */ +#define KASAN_GLOBAL_REDZONE 0xF9 /* redzone for global variable */ + +/* Stack redzone shadow values. Compiler ABI, do not change. */ +#define KASAN_STACK_LEFT 0xF1 +#define KASAN_STACK_MID 0xF2 +#define KASAN_STACK_RIGHT 0xF3 +#define KASAN_STACK_PARTIAL 0xF4 + +/* alloca redzone shadow values. */ +#define KASAN_ALLOCA_LEFT 0xCA +#define KASAN_ALLOCA_RIGHT 0xCB + +/* alloca redzone size. Compiler ABI, do not change. */ +#define KASAN_ALLOCA_REDZONE_SIZE 32 + +/* Stack frame marker. Compiler ABI, do not change. */ +#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3 + +/* Dummy value to avoid breaking randconfig/all*config builds. */ +#ifndef KASAN_ABI_VERSION +#define KASAN_ABI_VERSION 1 +#endif + +#endif /* CONFIG_KASAN_GENERIC */ + +/* Metadata layout customization. */ +#define META_BYTES_PER_BLOCK 1 +#define META_BLOCKS_PER_ROW 16 +#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK) +#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, + KASAN_REPORT_DOUBLE_FREE, +}; + +struct kasan_report_info { + /* Filled in by kasan_report_*(). */ + enum kasan_report_type type; + const void *access_addr; + size_t access_size; + bool is_write; + unsigned long ip; + + /* Filled in by the common reporting code. */ + const void *first_bad_addr; + struct kmem_cache *cache; + void *object; + size_t alloc_size; + + /* 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. */ +struct kasan_source_location { + const char *filename; + int line_no; + int column_no; +}; + +/* Do not change the struct layout: compiler ABI. */ +struct kasan_global { + const void *beg; /* Address of the beginning of the global variable. */ + size_t size; /* Size of the global variable. */ + size_t size_with_redzone; /* Size of the variable + size of the redzone. 32 bytes aligned. */ + const void *name; + const void *module_name; /* Name of the module where the global variable is declared. */ + unsigned long has_dynamic_init; /* This is needed for C++. */ +#if KASAN_ABI_VERSION >= 4 + struct kasan_source_location *location; +#endif +#if KASAN_ABI_VERSION >= 5 + char *odr_indicator; +#endif +}; + +/* Structures for keeping alloc and free meta. */ + +#ifdef CONFIG_KASAN_GENERIC + +struct kasan_alloc_meta { + struct kasan_track alloc_track; + /* Free track is stored in kasan_free_meta. */ + depot_stack_handle_t aux_stack[2]; +}; + +struct qlist_node { + struct qlist_node *next; +}; + +/* + * Free meta is stored either in the object itself or in the redzone after the + * object. In the former case, free meta offset is 0. In the latter case, the + * offset is between 0 and INT_MAX. INT_MAX marks that free meta is not present. + */ +#define KASAN_NO_FREE_META INT_MAX + +/* + * Free meta is only used by Generic mode while the object is in quarantine. + * After that, slab allocator stores the freelist pointer in the object. + */ +struct kasan_free_meta { + struct qlist_node quarantine_link; + struct kasan_track free_track; +}; + +#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 defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) + +#ifndef kasan_shadow_to_mem +static inline const void *kasan_shadow_to_mem(const void *shadow_addr) +{ + return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET) + << KASAN_SHADOW_SCALE_SHIFT); +} +#endif + +#ifndef addr_has_metadata +static __always_inline bool addr_has_metadata(const void *addr) +{ + return (kasan_reset_tag(addr) >= + kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); +} +#endif + +/** + * kasan_check_range - Check memory region, and report if invalid access. + * @addr: the accessed address + * @size: the accessed size + * @write: true if access is a write access + * @ret_ip: return address + * @return: true if access was valid, false if invalid + */ +bool kasan_check_range(const void *addr, size_t size, bool write, + unsigned long ret_ip); + +#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ + +static __always_inline bool addr_has_metadata(const void *addr) +{ + return (is_vmalloc_addr(addr) || virt_addr_valid(addr)); +} + +#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ + +const void *kasan_find_first_bad_addr(const void *addr, size_t size); +size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache); +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 + +#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(const void *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 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_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)) +bool kasan_quarantine_put(struct kmem_cache *cache, void *object); +void kasan_quarantine_reduce(void); +void kasan_quarantine_remove_cache(struct kmem_cache *cache); +#else +static inline bool kasan_quarantine_put(struct kmem_cache *cache, void *object) { return false; } +static inline void kasan_quarantine_reduce(void) { } +static inline void kasan_quarantine_remove_cache(struct kmem_cache *cache) { } +#endif + +#ifndef arch_kasan_set_tag +static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) +{ + return addr; +} +#endif +#ifndef arch_kasan_get_tag +#define arch_kasan_get_tag(addr) 0 +#endif + +#define set_tag(addr, tag) ((void *)arch_kasan_set_tag((addr), (tag))) +#define get_tag(addr) arch_kasan_get_tag(addr) + +#ifdef CONFIG_KASAN_HW_TAGS + +#define hw_enable_tag_checks_sync() arch_enable_tag_checks_sync() +#define hw_enable_tag_checks_async() arch_enable_tag_checks_async() +#define hw_enable_tag_checks_asymm() arch_enable_tag_checks_asymm() +#define hw_suppress_tag_checks_start() arch_suppress_tag_checks_start() +#define hw_suppress_tag_checks_stop() arch_suppress_tag_checks_stop() +#define hw_force_async_tag_fault() arch_force_async_tag_fault() +#define hw_get_random_tag() arch_get_random_tag() +#define hw_get_mem_tag(addr) arch_get_mem_tag(addr) +#define hw_set_mem_tag_range(addr, size, tag, init) \ + arch_set_mem_tag_range((addr), (size), (tag), (init)) + +void kasan_enable_hw_tags(void); + +#else /* CONFIG_KASAN_HW_TAGS */ + +static inline void kasan_enable_hw_tags(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); + +#else /* CONFIG_KASAN_HW_TAGS && CONFIG_KASAN_KUNIT_TEST */ + +static inline void kasan_force_async_fault(void) { } + +#endif /* CONFIG_KASAN_HW_TAGS && CONFIG_KASAN_KUNIT_TEST */ + +#ifdef CONFIG_KASAN_SW_TAGS +u8 kasan_random_tag(void); +#elif defined(CONFIG_KASAN_HW_TAGS) +static inline u8 kasan_random_tag(void) { return hw_get_random_tag(); } +#else +static inline u8 kasan_random_tag(void) { return 0; } +#endif + +#ifdef CONFIG_KASAN_HW_TAGS + +static inline void kasan_poison(const void *addr, size_t size, u8 value, bool init) +{ + addr = kasan_reset_tag(addr); + + /* Skip KFENCE memory if called explicitly outside of sl*b. */ + if (is_kfence_address(addr)) + return; + + if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK)) + return; + if (WARN_ON(size & KASAN_GRANULE_MASK)) + return; + + hw_set_mem_tag_range((void *)addr, size, value, init); +} + +static inline void kasan_unpoison(const void *addr, size_t size, bool init) +{ + u8 tag = get_tag(addr); + + addr = kasan_reset_tag(addr); + + /* Skip KFENCE memory if called explicitly outside of sl*b. */ + if (is_kfence_address(addr)) + return; + + if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK)) + return; + size = round_up(size, KASAN_GRANULE_SIZE); + + hw_set_mem_tag_range((void *)addr, size, tag, init); +} + +static inline bool kasan_byte_accessible(const void *addr) +{ + u8 ptr_tag = get_tag(addr); + u8 mem_tag = hw_get_mem_tag((void *)addr); + + return ptr_tag == KASAN_TAG_KERNEL || ptr_tag == mem_tag; +} + +#else /* CONFIG_KASAN_HW_TAGS */ + +/** + * kasan_poison - mark the memory range as inaccessible + * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE + * @size - range size, must be aligned to KASAN_GRANULE_SIZE + * @value - value that's written to metadata for the range + * @init - whether to initialize the memory range (only for hardware tag-based) + * + * The size gets aligned to KASAN_GRANULE_SIZE before marking the range. + */ +void kasan_poison(const void *addr, size_t size, u8 value, bool init); + +/** + * kasan_unpoison - mark the memory range as accessible + * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE + * @size - range size, can be unaligned + * @init - whether to initialize the memory range (only for hardware tag-based) + * + * For the tag-based modes, the @size gets aligned to KASAN_GRANULE_SIZE before + * marking the range. + * For the generic mode, the last granule of the memory range gets partially + * unpoisoned based on the @size. + */ +void kasan_unpoison(const void *addr, size_t size, bool init); + +bool kasan_byte_accessible(const void *addr); + +#endif /* CONFIG_KASAN_HW_TAGS */ + +#ifdef CONFIG_KASAN_GENERIC + +/** + * kasan_poison_last_granule - mark the last granule of the memory range as + * inaccessible + * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE + * @size - range size + * + * This function is only available for the generic mode, as it's the only mode + * that has partially poisoned memory granules. + */ +void kasan_poison_last_granule(const void *address, size_t size); + +#else /* CONFIG_KASAN_GENERIC */ + +static inline void kasan_poison_last_granule(const void *address, size_t size) { } + +#endif /* CONFIG_KASAN_GENERIC */ + +#ifndef kasan_arch_is_ready +static inline bool kasan_arch_is_ready(void) { return true; } +#elif !defined(CONFIG_KASAN_GENERIC) || !defined(CONFIG_KASAN_OUTLINE) +#error kasan_arch_is_ready only works in KASAN generic outline mode! +#endif + +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) + +void kasan_kunit_test_suite_start(void); +void kasan_kunit_test_suite_end(void); + +#else /* CONFIG_KASAN_KUNIT_TEST */ + +static inline void kasan_kunit_test_suite_start(void) { } +static inline void kasan_kunit_test_suite_end(void) { } + +#endif /* CONFIG_KASAN_KUNIT_TEST */ + +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) || IS_ENABLED(CONFIG_KASAN_MODULE_TEST) + +bool kasan_save_enable_multi_shot(void); +void kasan_restore_multi_shot(bool enabled); + +#endif + +/* + * Exported functions for interfaces called from assembly or from generated + * code. Declared here to avoid warnings about missing declarations. + */ + +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark); +void __asan_register_globals(void *globals, ssize_t size); +void __asan_unregister_globals(void *globals, ssize_t size); +void __asan_handle_no_return(void); +void __asan_alloca_poison(void *, ssize_t size); +void __asan_allocas_unpoison(void *stack_top, ssize_t stack_bottom); + +void __asan_load1(void *); +void __asan_store1(void *); +void __asan_load2(void *); +void __asan_store2(void *); +void __asan_load4(void *); +void __asan_store4(void *); +void __asan_load8(void *); +void __asan_store8(void *); +void __asan_load16(void *); +void __asan_store16(void *); +void __asan_loadN(void *, ssize_t size); +void __asan_storeN(void *, ssize_t size); + +void __asan_load1_noabort(void *); +void __asan_store1_noabort(void *); +void __asan_load2_noabort(void *); +void __asan_store2_noabort(void *); +void __asan_load4_noabort(void *); +void __asan_store4_noabort(void *); +void __asan_load8_noabort(void *); +void __asan_store8_noabort(void *); +void __asan_load16_noabort(void *); +void __asan_store16_noabort(void *); +void __asan_loadN_noabort(void *, ssize_t size); +void __asan_storeN_noabort(void *, ssize_t size); + +void __asan_report_load1_noabort(void *); +void __asan_report_store1_noabort(void *); +void __asan_report_load2_noabort(void *); +void __asan_report_store2_noabort(void *); +void __asan_report_load4_noabort(void *); +void __asan_report_store4_noabort(void *); +void __asan_report_load8_noabort(void *); +void __asan_report_store8_noabort(void *); +void __asan_report_load16_noabort(void *); +void __asan_report_store16_noabort(void *); +void __asan_report_load_n_noabort(void *, ssize_t size); +void __asan_report_store_n_noabort(void *, ssize_t size); + +void __asan_set_shadow_00(const void *addr, ssize_t size); +void __asan_set_shadow_f1(const void *addr, ssize_t size); +void __asan_set_shadow_f2(const void *addr, ssize_t size); +void __asan_set_shadow_f3(const void *addr, ssize_t size); +void __asan_set_shadow_f5(const void *addr, ssize_t size); +void __asan_set_shadow_f8(const void *addr, ssize_t size); + +void *__asan_memset(void *addr, int c, ssize_t len); +void *__asan_memmove(void *dest, const void *src, ssize_t len); +void *__asan_memcpy(void *dest, const void *src, ssize_t len); + +void __hwasan_load1_noabort(void *); +void __hwasan_store1_noabort(void *); +void __hwasan_load2_noabort(void *); +void __hwasan_store2_noabort(void *); +void __hwasan_load4_noabort(void *); +void __hwasan_store4_noabort(void *); +void __hwasan_load8_noabort(void *); +void __hwasan_store8_noabort(void *); +void __hwasan_load16_noabort(void *); +void __hwasan_store16_noabort(void *); +void __hwasan_loadN_noabort(void *, ssize_t size); +void __hwasan_storeN_noabort(void *, ssize_t size); + +void __hwasan_tag_memory(void *, u8 tag, ssize_t size); + +void *__hwasan_memset(void *addr, int c, ssize_t len); +void *__hwasan_memmove(void *dest, const void *src, ssize_t len); +void *__hwasan_memcpy(void *dest, const void *src, ssize_t len); + +void kasan_tag_mismatch(void *addr, unsigned long access_info, + unsigned long ret_ip); + +#endif /* __MM_KASAN_KASAN_H */ diff --git a/mm/kasan/kasan_test.c b/mm/kasan/kasan_test.c new file mode 100644 index 000000000..b61cc6a42 --- /dev/null +++ b/mm/kasan/kasan_test.c @@ -0,0 +1,1581 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + */ + +#define pr_fmt(fmt) "kasan_test: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "kasan.h" + +#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE) + +static bool multishot; + +/* Fields set based on lines observed in the console. */ +static struct { + bool report_found; + bool async_fault; +} test_status; + +/* + * 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; + +/* Probe for console output: obtains test_status lines of interest. */ +static void probe_console(void *ignore, const char *buf, size_t len) +{ + if (strnstr(buf, "BUG: KASAN: ", len)) + WRITE_ONCE(test_status.report_found, true); + else if (strnstr(buf, "Asynchronous fault: ", len)) + WRITE_ONCE(test_status.async_fault, true); +} + +static int kasan_suite_init(struct kunit_suite *suite) +{ + if (!kasan_enabled()) { + pr_err("Can't run KASAN tests with KASAN disabled"); + return -1; + } + + /* Stop failing KUnit tests on KASAN reports. */ + kasan_kunit_test_suite_start(); + + /* + * Temporarily enable multi-shot mode. Otherwise, KASAN would only + * report the first detected bug and panic the kernel if panic_on_warn + * is enabled. + */ + multishot = kasan_save_enable_multi_shot(); + + register_trace_console(probe_console, NULL); + return 0; +} + +static void kasan_suite_exit(struct kunit_suite *suite) +{ + kasan_kunit_test_suite_end(); + kasan_restore_multi_shot(multishot); + unregister_trace_console(probe_console, NULL); + tracepoint_synchronize_unregister(); +} + +static void kasan_test_exit(struct kunit *test) +{ + KUNIT_EXPECT_FALSE(test, READ_ONCE(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.async_fault)) \ + kasan_enable_hw_tags(); \ + migrate_enable(); \ + } \ + WRITE_ONCE(test_status.report_found, false); \ + WRITE_ONCE(test_status.async_fault, 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) + +#define KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test) do { \ + if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \ + break; /* No compiler instrumentation. */ \ + if (IS_ENABLED(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX)) \ + break; /* Should always be instrumented! */ \ + if (IS_ENABLED(CONFIG_GENERIC_ENTRY)) \ + kunit_skip((test), "Test requires checked mem*()"); \ +} 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + /* 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + /* + * 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + 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; + + KASAN_TEST_NEEDS_CHECKED_MEMINTRINSICS(test); + + /* + * 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() does NOT unpoison whole object. */ +static void ksize_unpoisons_memory(struct kunit *test) +{ + char *ptr; + size_t size = 128 - KASAN_GRANULE_SIZE - 5; + size_t real_size; + + ptr = kmalloc(size, GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + real_size = ksize(ptr); + KUNIT_EXPECT_GT(test, real_size, size); + + OPTIMIZER_HIDE_VAR(ptr); + + /* These accesses shouldn't trigger a KASAN report. */ + ptr[0] = 'x'; + ptr[size - 1] = 'x'; + + /* These must trigger a KASAN report. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size + 5]); + KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[real_size - 1]); + + 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)); +} + +/* + * The two tests below check that Generic KASAN prints auxiliary stack traces + * for RCU callbacks and workqueues. The reports need to be inspected manually. + * + * These tests are still enabled for other KASAN modes to make sure that all + * modes report bad accesses in tested scenarios. + */ + +static struct kasan_rcu_info { + int i; + struct rcu_head rcu; +} *global_rcu_ptr; + +static void rcu_uaf_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 void rcu_uaf(struct kunit *test) +{ + struct kasan_rcu_info *ptr; + + ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + + global_rcu_ptr = rcu_dereference_protected( + (struct kasan_rcu_info __rcu *)ptr, NULL); + + KUNIT_EXPECT_KASAN_FAIL(test, + call_rcu(&global_rcu_ptr->rcu, rcu_uaf_reclaim); + rcu_barrier()); +} + +static void workqueue_uaf_work(struct work_struct *work) +{ + kfree(work); +} + +static void workqueue_uaf(struct kunit *test) +{ + struct workqueue_struct *workqueue; + struct work_struct *work; + + workqueue = create_workqueue("kasan_workqueue_test"); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, workqueue); + + work = kmalloc(sizeof(struct work_struct), GFP_KERNEL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, work); + + INIT_WORK(work, workqueue_uaf_work); + queue_work(workqueue, work); + destroy_workqueue(workqueue); + + KUNIT_EXPECT_KASAN_FAIL(test, + ((volatile struct work_struct *)work)->data); +} + +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 = get_random_u32_inclusive(1, 1024); + 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 = get_random_u32_inclusive(1, 4); + 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 = get_random_u32_inclusive(1, 1024); + 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(rcu_uaf), + KUNIT_CASE(workqueue_uaf), + 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", + .test_cases = kasan_kunit_test_cases, + .exit = kasan_test_exit, + .suite_init = kasan_suite_init, + .suite_exit = kasan_suite_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 000000000..7be7bed45 --- /dev/null +++ b/mm/kasan/kasan_test_module.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + */ + +#define pr_fmt(fmt) "kasan test: %s " fmt, __func__ + +#include +#include +#include +#include +#include + +#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 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_restore_multi_shot(multishot); + return -EAGAIN; +} + +module_init(test_kasan_module_init); +MODULE_LICENSE("GPL"); diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c new file mode 100644 index 000000000..152dca73f --- /dev/null +++ b/mm/kasan/quarantine.c @@ -0,0 +1,420 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KASAN quarantine. + * + * Author: Alexander Potapenko + * Copyright (C) 2016 Google, Inc. + * + * Based on code by Dmitry Chernenkov. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../slab.h" +#include "kasan.h" + +/* Data structure and operations for quarantine queues. */ + +/* + * Each queue is a single-linked list, which also stores the total size of + * objects inside of it. + */ +struct qlist_head { + struct qlist_node *head; + struct qlist_node *tail; + size_t bytes; + bool offline; +}; + +#define QLIST_INIT { NULL, NULL, 0 } + +static bool qlist_empty(struct qlist_head *q) +{ + return !q->head; +} + +static void qlist_init(struct qlist_head *q) +{ + q->head = q->tail = NULL; + q->bytes = 0; +} + +static void qlist_put(struct qlist_head *q, struct qlist_node *qlink, + size_t size) +{ + if (unlikely(qlist_empty(q))) + q->head = qlink; + else + q->tail->next = qlink; + q->tail = qlink; + qlink->next = NULL; + q->bytes += size; +} + +static void qlist_move_all(struct qlist_head *from, struct qlist_head *to) +{ + if (unlikely(qlist_empty(from))) + return; + + if (qlist_empty(to)) { + *to = *from; + qlist_init(from); + return; + } + + to->tail->next = from->head; + to->tail = from->tail; + to->bytes += from->bytes; + + qlist_init(from); +} + +#define QUARANTINE_PERCPU_SIZE (1 << 20) +#define QUARANTINE_BATCHES \ + (1024 > 4 * CONFIG_NR_CPUS ? 1024 : 4 * CONFIG_NR_CPUS) + +/* + * The object quarantine consists of per-cpu queues and a global queue, + * guarded by quarantine_lock. + */ +static DEFINE_PER_CPU(struct qlist_head, cpu_quarantine); + +/* Round-robin FIFO array of batches. */ +static struct qlist_head global_quarantine[QUARANTINE_BATCHES]; +static int quarantine_head; +static int quarantine_tail; +/* Total size of all objects in global_quarantine across all batches. */ +static unsigned long quarantine_size; +static DEFINE_RAW_SPINLOCK(quarantine_lock); +DEFINE_STATIC_SRCU(remove_cache_srcu); + +struct cpu_shrink_qlist { + raw_spinlock_t lock; + struct qlist_head qlist; +}; + +static DEFINE_PER_CPU(struct cpu_shrink_qlist, shrink_qlist) = { + .lock = __RAW_SPIN_LOCK_UNLOCKED(shrink_qlist.lock), +}; + +/* Maximum size of the global queue. */ +static unsigned long quarantine_max_size; + +/* + * Target size of a batch in global_quarantine. + * Usually equal to QUARANTINE_PERCPU_SIZE unless we have too much RAM. + */ +static unsigned long quarantine_batch_size; + +/* + * The fraction of physical memory the quarantine is allowed to occupy. + * Quarantine doesn't support memory shrinker with SLAB allocator, so we keep + * the ratio low to avoid OOM. + */ +#define QUARANTINE_FRACTION 32 + +static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink) +{ + return virt_to_slab(qlink)->slab_cache; +} + +static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache) +{ + struct kasan_free_meta *free_info = + container_of(qlink, struct kasan_free_meta, + quarantine_link); + + return ((void *)free_info) - cache->kasan_info.free_meta_offset; +} + +static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) +{ + void *object = qlink_to_object(qlink, cache); + struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); + unsigned long flags; + + if (IS_ENABLED(CONFIG_SLAB)) + local_irq_save(flags); + + /* + * If init_on_free is enabled and KASAN's free metadata is stored in + * the object, zero the metadata. Otherwise, the object's memory will + * not be properly zeroed, as KASAN saves the metadata after the slab + * allocator zeroes the object. + */ + if (slab_want_init_on_free(cache) && + cache->kasan_info.free_meta_offset == 0) + memzero_explicit(meta, sizeof(*meta)); + + /* + * As the object now gets freed from the quarantine, assume that its + * free track is no longer valid. + */ + *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE; + + ___cache_free(cache, object, _THIS_IP_); + + if (IS_ENABLED(CONFIG_SLAB)) + local_irq_restore(flags); +} + +static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache) +{ + struct qlist_node *qlink; + + if (unlikely(qlist_empty(q))) + return; + + qlink = q->head; + while (qlink) { + struct kmem_cache *obj_cache = + cache ? cache : qlink_to_cache(qlink); + struct qlist_node *next = qlink->next; + + qlink_free(qlink, obj_cache); + qlink = next; + } + qlist_init(q); +} + +bool kasan_quarantine_put(struct kmem_cache *cache, void *object) +{ + unsigned long flags; + struct qlist_head *q; + struct qlist_head temp = QLIST_INIT; + struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); + + /* + * If there's no metadata for this object, don't put it into + * quarantine. + */ + if (!meta) + return false; + + /* + * Note: irq must be disabled until after we move the batch to the + * global quarantine. Otherwise kasan_quarantine_remove_cache() can + * miss some objects belonging to the cache if they are in our local + * temp list. kasan_quarantine_remove_cache() executes on_each_cpu() + * at the beginning which ensures that it either sees the objects in + * per-cpu lists or in the global quarantine. + */ + local_irq_save(flags); + + q = this_cpu_ptr(&cpu_quarantine); + if (q->offline) { + local_irq_restore(flags); + return false; + } + qlist_put(q, &meta->quarantine_link, cache->size); + if (unlikely(q->bytes > QUARANTINE_PERCPU_SIZE)) { + qlist_move_all(q, &temp); + + raw_spin_lock(&quarantine_lock); + WRITE_ONCE(quarantine_size, quarantine_size + temp.bytes); + qlist_move_all(&temp, &global_quarantine[quarantine_tail]); + if (global_quarantine[quarantine_tail].bytes >= + READ_ONCE(quarantine_batch_size)) { + int new_tail; + + new_tail = quarantine_tail + 1; + if (new_tail == QUARANTINE_BATCHES) + new_tail = 0; + if (new_tail != quarantine_head) + quarantine_tail = new_tail; + } + raw_spin_unlock(&quarantine_lock); + } + + local_irq_restore(flags); + + return true; +} + +void kasan_quarantine_reduce(void) +{ + size_t total_size, new_quarantine_size, percpu_quarantines; + unsigned long flags; + int srcu_idx; + struct qlist_head to_free = QLIST_INIT; + + if (likely(READ_ONCE(quarantine_size) <= + READ_ONCE(quarantine_max_size))) + return; + + /* + * srcu critical section ensures that kasan_quarantine_remove_cache() + * will not miss objects belonging to the cache while they are in our + * local to_free list. srcu is chosen because (1) it gives us private + * grace period domain that does not interfere with anything else, + * and (2) it allows synchronize_srcu() to return without waiting + * if there are no pending read critical sections (which is the + * expected case). + */ + srcu_idx = srcu_read_lock(&remove_cache_srcu); + raw_spin_lock_irqsave(&quarantine_lock, flags); + + /* + * Update quarantine size in case of hotplug. Allocate a fraction of + * the installed memory to quarantine minus per-cpu queue limits. + */ + total_size = (totalram_pages() << PAGE_SHIFT) / + QUARANTINE_FRACTION; + percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus(); + new_quarantine_size = (total_size < percpu_quarantines) ? + 0 : total_size - percpu_quarantines; + WRITE_ONCE(quarantine_max_size, new_quarantine_size); + /* Aim at consuming at most 1/2 of slots in quarantine. */ + WRITE_ONCE(quarantine_batch_size, max((size_t)QUARANTINE_PERCPU_SIZE, + 2 * total_size / QUARANTINE_BATCHES)); + + if (likely(quarantine_size > quarantine_max_size)) { + qlist_move_all(&global_quarantine[quarantine_head], &to_free); + WRITE_ONCE(quarantine_size, quarantine_size - to_free.bytes); + quarantine_head++; + if (quarantine_head == QUARANTINE_BATCHES) + quarantine_head = 0; + } + + raw_spin_unlock_irqrestore(&quarantine_lock, flags); + + qlist_free_all(&to_free, NULL); + srcu_read_unlock(&remove_cache_srcu, srcu_idx); +} + +static void qlist_move_cache(struct qlist_head *from, + struct qlist_head *to, + struct kmem_cache *cache) +{ + struct qlist_node *curr; + + if (unlikely(qlist_empty(from))) + return; + + curr = from->head; + qlist_init(from); + while (curr) { + struct qlist_node *next = curr->next; + struct kmem_cache *obj_cache = qlink_to_cache(curr); + + if (obj_cache == cache) + qlist_put(to, curr, obj_cache->size); + else + qlist_put(from, curr, obj_cache->size); + + curr = next; + } +} + +static void __per_cpu_remove_cache(struct qlist_head *q, void *arg) +{ + struct kmem_cache *cache = arg; + unsigned long flags; + struct cpu_shrink_qlist *sq; + + sq = this_cpu_ptr(&shrink_qlist); + raw_spin_lock_irqsave(&sq->lock, flags); + qlist_move_cache(q, &sq->qlist, cache); + raw_spin_unlock_irqrestore(&sq->lock, flags); +} + +static void per_cpu_remove_cache(void *arg) +{ + struct qlist_head *q; + + q = this_cpu_ptr(&cpu_quarantine); + /* + * Ensure the ordering between the writing to q->offline and + * per_cpu_remove_cache. Prevent cpu_quarantine from being corrupted + * by interrupt. + */ + if (READ_ONCE(q->offline)) + return; + __per_cpu_remove_cache(q, arg); +} + +/* Free all quarantined objects belonging to cache. */ +void kasan_quarantine_remove_cache(struct kmem_cache *cache) +{ + unsigned long flags, i; + struct qlist_head to_free = QLIST_INIT; + int cpu; + struct cpu_shrink_qlist *sq; + + /* + * Must be careful to not miss any objects that are being moved from + * per-cpu list to the global quarantine in kasan_quarantine_put(), + * nor objects being freed in kasan_quarantine_reduce(). on_each_cpu() + * achieves the first goal, while synchronize_srcu() achieves the + * second. + */ + on_each_cpu(per_cpu_remove_cache, cache, 1); + + for_each_online_cpu(cpu) { + sq = per_cpu_ptr(&shrink_qlist, cpu); + raw_spin_lock_irqsave(&sq->lock, flags); + qlist_move_cache(&sq->qlist, &to_free, cache); + raw_spin_unlock_irqrestore(&sq->lock, flags); + } + qlist_free_all(&to_free, cache); + + raw_spin_lock_irqsave(&quarantine_lock, flags); + for (i = 0; i < QUARANTINE_BATCHES; i++) { + if (qlist_empty(&global_quarantine[i])) + continue; + qlist_move_cache(&global_quarantine[i], &to_free, cache); + /* Scanning whole quarantine can take a while. */ + raw_spin_unlock_irqrestore(&quarantine_lock, flags); + cond_resched(); + raw_spin_lock_irqsave(&quarantine_lock, flags); + } + raw_spin_unlock_irqrestore(&quarantine_lock, flags); + + qlist_free_all(&to_free, cache); + + synchronize_srcu(&remove_cache_srcu); +} + +static int kasan_cpu_online(unsigned int cpu) +{ + this_cpu_ptr(&cpu_quarantine)->offline = false; + return 0; +} + +static int kasan_cpu_offline(unsigned int cpu) +{ + struct qlist_head *q; + + q = this_cpu_ptr(&cpu_quarantine); + /* Ensure the ordering between the writing to q->offline and + * qlist_free_all. Otherwise, cpu_quarantine may be corrupted + * by interrupt. + */ + WRITE_ONCE(q->offline, true); + barrier(); + qlist_free_all(q, NULL); + return 0; +} + +static int __init kasan_cpu_quarantine_init(void) +{ + int ret = 0; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "mm/kasan:online", + kasan_cpu_online, kasan_cpu_offline); + if (ret < 0) + pr_err("kasan cpu quarantine register failed [%d]\n", ret); + return ret; +} +late_initcall(kasan_cpu_quarantine_init); diff --git a/mm/kasan/report.c b/mm/kasan/report.c new file mode 100644 index 000000000..6e3cb118d --- /dev/null +++ b/mm/kasan/report.c @@ -0,0 +1,662 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains common KASAN error reporting code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "kasan.h" +#include "../slab.h" + +static unsigned long kasan_flags; + +#define KASAN_BIT_REPORTED 0 +#define KASAN_BIT_MULTI_SHOT 1 + +enum kasan_arg_fault { + KASAN_ARG_FAULT_DEFAULT, + KASAN_ARG_FAULT_REPORT, + KASAN_ARG_FAULT_PANIC, + KASAN_ARG_FAULT_PANIC_ON_WRITE, +}; + +static enum kasan_arg_fault kasan_arg_fault __ro_after_init = KASAN_ARG_FAULT_DEFAULT; + +/* kasan.fault=report/panic */ +static int __init early_kasan_fault(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "report")) + kasan_arg_fault = KASAN_ARG_FAULT_REPORT; + else if (!strcmp(arg, "panic")) + kasan_arg_fault = KASAN_ARG_FAULT_PANIC; + else if (!strcmp(arg, "panic_on_write")) + kasan_arg_fault = KASAN_ARG_FAULT_PANIC_ON_WRITE; + else + return -EINVAL; + + return 0; +} +early_param("kasan.fault", early_kasan_fault); + +static int __init kasan_set_multi_shot(char *str) +{ + set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); + return 1; +} +__setup("kasan_multi_shot", kasan_set_multi_shot); + +/* + * This function is used to check whether KASAN reports are suppressed for + * software KASAN modes via kasan_disable/enable_current() critical sections. + * + * This is done to avoid: + * 1. False-positive reports when accessing slab metadata, + * 2. Deadlocking when poisoned memory is accessed by the reporting code. + * + * Hardware Tag-Based KASAN instead relies on: + * For #1: Resetting tags via kasan_reset_tag(). + * For #2: Suppression of tag checks via CPU, see report_suppress_start/end(). + */ +static bool report_suppressed_sw(void) +{ +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) + if (current->kasan_depth) + return true; +#endif + return false; +} + +static void report_suppress_start(void) +{ +#ifdef CONFIG_KASAN_HW_TAGS + /* + * Disable preemption for the duration of printing a KASAN report, as + * hw_suppress_tag_checks_start() disables checks on the current CPU. + */ + preempt_disable(); + hw_suppress_tag_checks_start(); +#else + kasan_disable_current(); +#endif +} + +static void report_suppress_stop(void) +{ +#ifdef CONFIG_KASAN_HW_TAGS + hw_suppress_tag_checks_stop(); + preempt_enable(); +#else + kasan_enable_current(); +#endif +} + +/* + * Used to avoid reporting more than one KASAN bug unless kasan_multi_shot + * is enabled. Note that KASAN tests effectively enable kasan_multi_shot + * for their duration. + */ +static bool report_enabled(void) +{ + if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) + return true; + return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags); +} + +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) || IS_ENABLED(CONFIG_KASAN_MODULE_TEST) + +bool kasan_save_enable_multi_shot(void) +{ + return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); +} +EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot); + +void kasan_restore_multi_shot(bool enabled) +{ + if (!enabled) + clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); +} +EXPORT_SYMBOL_GPL(kasan_restore_multi_shot); + +#endif + +#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) + +/* + * Whether the KASAN KUnit test suite is currently being executed. + * Updated in kasan_test.c. + */ +static bool kasan_kunit_executing; + +void kasan_kunit_test_suite_start(void) +{ + WRITE_ONCE(kasan_kunit_executing, true); +} +EXPORT_SYMBOL_GPL(kasan_kunit_test_suite_start); + +void kasan_kunit_test_suite_end(void) +{ + WRITE_ONCE(kasan_kunit_executing, false); +} +EXPORT_SYMBOL_GPL(kasan_kunit_test_suite_end); + +static bool kasan_kunit_test_suite_executing(void) +{ + return READ_ONCE(kasan_kunit_executing); +} + +#else /* CONFIG_KASAN_KUNIT_TEST */ + +static inline bool kasan_kunit_test_suite_executing(void) { return false; } + +#endif /* CONFIG_KASAN_KUNIT_TEST */ + +#if IS_ENABLED(CONFIG_KUNIT) + +static void fail_non_kasan_kunit_test(void) +{ + struct kunit *test; + + if (kasan_kunit_test_suite_executing()) + return; + + test = current->kunit_test; + if (test) + kunit_set_failure(test); +} + +#else /* CONFIG_KUNIT */ + +static inline void fail_non_kasan_kunit_test(void) { } + +#endif /* CONFIG_KUNIT */ + +static DEFINE_SPINLOCK(report_lock); + +static void start_report(unsigned long *flags, bool sync) +{ + fail_non_kasan_kunit_test(); + /* Respect the /proc/sys/kernel/traceoff_on_warning interface. */ + disable_trace_on_warning(); + /* Do not allow LOCKDEP mangling KASAN reports. */ + lockdep_off(); + /* Make sure we don't end up in loop. */ + report_suppress_start(); + spin_lock_irqsave(&report_lock, *flags); + pr_err("==================================================================\n"); +} + +static void end_report(unsigned long *flags, const void *addr, bool is_write) +{ + if (addr) + trace_error_report_end(ERROR_DETECTOR_KASAN, + (unsigned long)addr); + pr_err("==================================================================\n"); + spin_unlock_irqrestore(&report_lock, *flags); + if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) + check_panic_on_warn("KASAN"); + switch (kasan_arg_fault) { + case KASAN_ARG_FAULT_DEFAULT: + case KASAN_ARG_FAULT_REPORT: + break; + case KASAN_ARG_FAULT_PANIC: + panic("kasan.fault=panic set ...\n"); + break; + case KASAN_ARG_FAULT_PANIC_ON_WRITE: + if (is_write) + panic("kasan.fault=panic_on_write set ...\n"); + break; + } + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); + lockdep_on(); + report_suppress_stop(); +} + +static void print_error_description(struct kasan_report_info *info) +{ + pr_err("BUG: KASAN: %s in %pS\n", info->bug_type, (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; + } + + 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, + info->access_addr, current->comm, task_pid_nr(current)); + else + pr_err("%s at addr %px by task %s/%d\n", + info->is_write ? "Write" : "Read", + info->access_addr, current->comm, task_pid_nr(current)); +} + +static void print_track(struct kasan_track *track, const char *prefix) +{ + pr_err("%s by task %u:\n", prefix, track->pid); + if (track->stack) + stack_depot_print(track->stack); + else + pr_err("(stack is not available)\n"); +} + +static inline struct page *addr_to_page(const void *addr) +{ + if (virt_addr_valid(addr)) + return virt_to_head_page(addr); + return NULL; +} + +static void describe_object_addr(const void *addr, struct kasan_report_info *info) +{ + unsigned long access_addr = (unsigned long)addr; + unsigned long object_addr = (unsigned long)info->object; + const char *rel_type, *region_state = ""; + int rel_bytes; + + pr_err("The buggy address belongs to the object at %px\n" + " which belongs to the cache %s of size %d\n", + info->object, info->cache->name, info->cache->object_size); + + if (access_addr < object_addr) { + rel_type = "to the left"; + rel_bytes = object_addr - access_addr; + } else if (access_addr >= object_addr + info->alloc_size) { + rel_type = "to the right"; + rel_bytes = access_addr - (object_addr + info->alloc_size); + } else { + rel_type = "inside"; + rel_bytes = access_addr - object_addr; + } + + /* + * Tag-Based modes use the stack ring to infer the bug type, but the + * memory region state description is generated based on the metadata. + * Thus, defining the region state as below can contradict the metadata. + * Fixing this requires further improvements, so only infer the state + * for the Generic mode. + */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) { + if (strcmp(info->bug_type, "slab-out-of-bounds") == 0) + region_state = "allocated "; + else if (strcmp(info->bug_type, "slab-use-after-free") == 0) + region_state = "freed "; + } + + pr_err("The buggy address is located %d bytes %s of\n" + " %s%zu-byte region [%px, %px)\n", + rel_bytes, rel_type, region_state, info->alloc_size, + (void *)object_addr, (void *)(object_addr + info->alloc_size)); +} + +static void describe_object_stacks(struct kasan_report_info *info) +{ + if (info->alloc_track.stack) { + print_track(&info->alloc_track, "Allocated"); + pr_err("\n"); + } + + if (info->free_track.stack) { + print_track(&info->free_track, "Freed"); + pr_err("\n"); + } + + kasan_print_aux_stacks(info->cache, info->object); +} + +static void describe_object(const void *addr, struct kasan_report_info *info) +{ + if (kasan_stack_collection_enabled()) + describe_object_stacks(info); + describe_object_addr(addr, info); +} + +static inline bool kernel_or_module_addr(const void *addr) +{ + if (is_kernel((unsigned long)addr)) + return true; + if (is_module_address((unsigned long)addr)) + return true; + return false; +} + +static inline bool init_task_stack_addr(const void *addr) +{ + return addr >= (void *)&init_thread_union.stack && + (addr <= (void *)&init_thread_union.stack + + sizeof(init_thread_union.stack)); +} + +static void print_address_description(void *addr, u8 tag, + struct kasan_report_info *info) +{ + struct page *page = addr_to_page(addr); + + dump_stack_lvl(KERN_ERR); + pr_err("\n"); + + if (info->cache && info->object) { + describe_object(addr, info); + pr_err("\n"); + } + + if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) { + pr_err("The buggy address belongs to the variable:\n"); + pr_err(" %pS\n", addr); + pr_err("\n"); + } + + if (object_is_on_stack(addr)) { + /* + * Currently, KASAN supports printing frame information only + * for accesses to the task's own stack. + */ + kasan_print_address_stack_frame(addr); + pr_err("\n"); + } + + if (is_vmalloc_addr(addr)) { + struct vm_struct *va = find_vm_area(addr); + + if (va) { + pr_err("The buggy address belongs to the virtual mapping at\n" + " [%px, %px) created by:\n" + " %pS\n", + va->addr, va->addr + va->size, va->caller); + pr_err("\n"); + + page = vmalloc_to_page(addr); + } + } + + if (page) { + pr_err("The buggy address belongs to the physical page:\n"); + dump_page(page, "kasan: bad access detected"); + pr_err("\n"); + } +} + +static bool meta_row_is_guilty(const void *row, const void *addr) +{ + return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW); +} + +static int meta_pointer_offset(const void *row, const void *addr) +{ + /* + * Memory state around the buggy address: + * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe + * ... + * + * The length of ">ff00ff00ff00ff00: " is + * 3 + (BITS_PER_LONG / 8) * 2 chars. + * The length of each granule metadata is 2 bytes + * plus 1 byte for space. + */ + return 3 + (BITS_PER_LONG / 8) * 2 + + (addr - row) / KASAN_GRANULE_SIZE * 3 + 1; +} + +static void print_memory_metadata(const void *addr) +{ + int i; + void *row; + + row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW) + - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW; + + pr_err("Memory state around the buggy address:\n"); + + for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) { + char buffer[4 + (BITS_PER_LONG / 8) * 2]; + char metadata[META_BYTES_PER_ROW]; + + snprintf(buffer, sizeof(buffer), + (i == 0) ? ">%px: " : " %px: ", row); + + /* + * We should not pass a shadow pointer to generic + * function, because generic functions may try to + * access kasan mapping for the passed address. + */ + kasan_metadata_fetch_row(&metadata[0], row); + + print_hex_dump(KERN_ERR, buffer, + DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1, + metadata, META_BYTES_PER_ROW, 0); + + if (meta_row_is_guilty(row, addr)) + pr_err("%*c\n", meta_pointer_offset(row, addr), '^'); + + row += META_MEM_BYTES_PER_ROW; + } +} + +static void print_report(struct kasan_report_info *info) +{ + void *addr = kasan_reset_tag((void *)info->access_addr); + u8 tag = get_tag((void *)info->access_addr); + + print_error_description(info); + if (addr_has_metadata(addr)) + kasan_print_tags(tag, info->first_bad_addr); + pr_err("\n"); + + 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((void *)info->access_addr); + struct slab *slab; + + if (info->type == KASAN_REPORT_ACCESS) + info->first_bad_addr = kasan_find_first_bad_addr( + (void *)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); + + /* Try to determine allocation size based on the metadata. */ + info->alloc_size = kasan_get_alloc_size(info->object, info->cache); + /* Fallback to the object size if failed. */ + if (!info->alloc_size) + info->alloc_size = info->cache->object_size; + } 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; + struct kasan_report_info info; + + /* + * Do not check report_suppressed_sw(), as an invalid-free cannot be + * caused by accessing poisoned memory and thus should not be suppressed + * by kasan_disable/enable_current() critical sections. + * + * Note that for Hardware Tag-Based KASAN, kasan_report_invalid_free() + * is triggered by explicit tag checks and not by the ones performed by + * the CPU. Thus, reporting invalid-free is not suppressed as well. + */ + if (unlikely(!report_enabled())) + return; + + start_report(&flags, true); + + memset(&info, 0, sizeof(info)); + info.type = type; + info.access_addr = ptr; + info.access_size = 0; + info.is_write = false; + info.ip = ip; + + complete_report_info(&info); + + print_report(&info); + + /* + * Invalid free is considered a "write" since the allocator's metadata + * updates involves writes. + */ + end_report(&flags, ptr, true); +} + +/* + * kasan_report() is the only reporting function that uses + * user_access_save/restore(): kasan_report_invalid_free() cannot be called + * from a UACCESS region, and kasan_report_async() is not used on x86. + */ +bool kasan_report(const void *addr, size_t size, bool is_write, + unsigned long ip) +{ + bool ret = true; + unsigned long ua_flags = user_access_save(); + unsigned long irq_flags; + struct kasan_report_info info; + + if (unlikely(report_suppressed_sw()) || unlikely(!report_enabled())) { + ret = false; + goto out; + } + + start_report(&irq_flags, true); + + memset(&info, 0, sizeof(info)); + info.type = KASAN_REPORT_ACCESS; + info.access_addr = addr; + info.access_size = size; + info.is_write = is_write; + info.ip = ip; + + complete_report_info(&info); + + print_report(&info); + + end_report(&irq_flags, (void *)addr, is_write); + +out: + user_access_restore(ua_flags); + + return ret; +} + +#ifdef CONFIG_KASAN_HW_TAGS +void kasan_report_async(void) +{ + unsigned long flags; + + /* + * Do not check report_suppressed_sw(), as + * kasan_disable/enable_current() critical sections do not affect + * Hardware Tag-Based KASAN. + */ + if (unlikely(!report_enabled())) + return; + + start_report(&flags, false); + pr_err("BUG: KASAN: invalid-access\n"); + pr_err("Asynchronous fault: no details available\n"); + pr_err("\n"); + dump_stack_lvl(KERN_ERR); + /* + * Conservatively set is_write=true, because no details are available. + * In this mode, kasan.fault=panic_on_write is like kasan.fault=panic. + */ + end_report(&flags, NULL, true); +} +#endif /* CONFIG_KASAN_HW_TAGS */ + +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) +/* + * With CONFIG_KASAN_INLINE, accesses to bogus pointers (outside the high + * canonical half of the address space) cause out-of-bounds shadow memory reads + * before the actual access. For addresses in the low canonical half of the + * address space, as well as most non-canonical addresses, that out-of-bounds + * shadow memory access lands in the non-canonical part of the address space. + * Help the user figure out what the original bogus pointer was. + */ +void kasan_non_canonical_hook(unsigned long addr) +{ + unsigned long orig_addr; + const char *bug_type; + + if (addr < KASAN_SHADOW_OFFSET) + return; + + orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT; + /* + * For faults near the shadow address for NULL, we can be fairly certain + * that this is a KASAN shadow memory access. + * For faults that correspond to shadow for low canonical addresses, we + * can still be pretty sure - that shadow region is a fairly narrow + * chunk of the non-canonical address space. + * But faults that look like shadow for non-canonical addresses are a + * really large chunk of the address space. In that case, we still + * print the decoded address, but make it clear that this is not + * necessarily what's actually going on. + */ + if (orig_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else if (orig_addr < TASK_SIZE) + bug_type = "probably user-memory-access"; + else + bug_type = "maybe wild-memory-access"; + pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type, + orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1); +} +#endif diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c new file mode 100644 index 000000000..51a1e8a88 --- /dev/null +++ b/mm/kasan/report_generic.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains generic KASAN specific error reporting code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "kasan.h" +#include "../slab.h" + +const void *kasan_find_first_bad_addr(const void *addr, size_t size) +{ + const void *p = addr; + + if (!addr_has_metadata(p)) + return p; + + while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p))) + p += KASAN_GRANULE_SIZE; + + return p; +} + +size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache) +{ + size_t size = 0; + u8 *shadow; + + /* + * Skip the addr_has_metadata check, as this function only operates on + * slab memory, which must have metadata. + */ + + /* + * The loop below returns 0 for freed objects, for which KASAN cannot + * calculate the allocation size based on the metadata. + */ + shadow = (u8 *)kasan_mem_to_shadow(object); + while (size < cache->object_size) { + if (*shadow == 0) + size += KASAN_GRANULE_SIZE; + else if (*shadow >= 1 && *shadow <= KASAN_GRANULE_SIZE - 1) + return size + *shadow; + else + return size; + shadow++; + } + + return cache->object_size; +} + +static const char *get_shadow_bug_type(struct kasan_report_info *info) +{ + const char *bug_type = "unknown-crash"; + u8 *shadow_addr; + + shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); + + /* + * If shadow byte value is in [0, KASAN_GRANULE_SIZE) we can look + * at the next shadow byte to determine the type of the bad access. + */ + if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1) + shadow_addr++; + + switch (*shadow_addr) { + case 0 ... KASAN_GRANULE_SIZE - 1: + /* + * In theory it's still possible to see these shadow values + * due to a data race in the kernel code. + */ + bug_type = "out-of-bounds"; + break; + case KASAN_PAGE_REDZONE: + case KASAN_SLAB_REDZONE: + bug_type = "slab-out-of-bounds"; + break; + case KASAN_GLOBAL_REDZONE: + bug_type = "global-out-of-bounds"; + break; + case KASAN_STACK_LEFT: + case KASAN_STACK_MID: + case KASAN_STACK_RIGHT: + case KASAN_STACK_PARTIAL: + bug_type = "stack-out-of-bounds"; + break; + case KASAN_PAGE_FREE: + bug_type = "use-after-free"; + break; + case KASAN_SLAB_FREE: + case KASAN_SLAB_FREETRACK: + bug_type = "slab-use-after-free"; + break; + case KASAN_ALLOCA_LEFT: + case KASAN_ALLOCA_RIGHT: + bug_type = "alloca-out-of-bounds"; + break; + case KASAN_VMALLOC_INVALID: + bug_type = "vmalloc-out-of-bounds"; + break; + } + + return bug_type; +} + +static const char *get_wild_bug_type(struct kasan_report_info *info) +{ + const char *bug_type = "unknown-crash"; + + if ((unsigned long)info->access_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else if ((unsigned long)info->access_addr < TASK_SIZE) + bug_type = "user-memory-access"; + else + bug_type = "wild-memory-access"; + + return bug_type; +} + +static const char *get_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. + * + * Casting negative numbers to size_t would indeed turn up as + * a large size_t and its value will be larger than ULONG_MAX/2, + * so that this can qualify as out-of-bounds. + */ + if (info->access_addr + info->access_size < info->access_addr) + return "out-of-bounds"; + + if (addr_has_metadata(info->access_addr)) + return get_shadow_bug_type(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, + unsigned long *value) +{ + const char *sep = strchr(*frame_descr, ' '); + + if (sep == NULL) + sep = *frame_descr + strlen(*frame_descr); + + if (token != NULL) { + const size_t tok_len = sep - *frame_descr; + + if (tok_len + 1 > max_tok_len) { + pr_err("KASAN internal error: frame description too long: %s\n", + *frame_descr); + return false; + } + + /* Copy token (+ 1 byte for '\0'). */ + strscpy(token, *frame_descr, tok_len + 1); + } + + /* Advance frame_descr past separator. */ + *frame_descr = sep + 1; + + if (value != NULL && kstrtoul(token, 10, value)) { + pr_err("KASAN internal error: not a valid number: %s\n", token); + return false; + } + + return true; +} + +static void print_decoded_frame_descr(const char *frame_descr) +{ + /* + * We need to parse the following string: + * "n alloc_1 alloc_2 ... alloc_n" + * where alloc_i looks like + * "offset size len name" + * or "offset size len name:line". + */ + + char token[64]; + unsigned long num_objects; + + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &num_objects)) + return; + + pr_err("\n"); + pr_err("This frame has %lu %s:\n", num_objects, + num_objects == 1 ? "object" : "objects"); + + while (num_objects--) { + unsigned long offset; + unsigned long size; + + /* access offset */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &offset)) + return; + /* access size */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + &size)) + return; + /* name length (unused) */ + if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL)) + return; + /* object name */ + if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), + NULL)) + return; + + /* Strip line number; without filename it's not very helpful. */ + strreplace(token, ':', '\0'); + + /* Finally, print object information. */ + pr_err(" [%lu, %lu) '%s'", offset, offset + size, token); + } +} + +/* Returns true only if the address is on the current task's stack. */ +static bool __must_check get_address_stack_frame_info(const void *addr, + unsigned long *offset, + const char **frame_descr, + const void **frame_pc) +{ + unsigned long aligned_addr; + unsigned long mem_ptr; + const u8 *shadow_bottom; + const u8 *shadow_ptr; + const unsigned long *frame; + + BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP)); + + aligned_addr = round_down((unsigned long)addr, sizeof(long)); + mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE); + shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr); + shadow_bottom = kasan_mem_to_shadow(end_of_stack(current)); + + while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) { + shadow_ptr--; + mem_ptr -= KASAN_GRANULE_SIZE; + } + + while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) { + shadow_ptr--; + mem_ptr -= KASAN_GRANULE_SIZE; + } + + if (shadow_ptr < shadow_bottom) + return false; + + frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE); + if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) { + pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n", + frame[0]); + return false; + } + + *offset = (unsigned long)addr - (unsigned long)frame; + *frame_descr = (const char *)frame[1]; + *frame_pc = (void *)frame[2]; + + return true; +} + +void kasan_print_address_stack_frame(const void *addr) +{ + unsigned long offset; + const char *frame_descr; + const void *frame_pc; + + if (WARN_ON(!object_is_on_stack(addr))) + return; + + pr_err("The buggy address belongs to stack of task %s/%d\n", + current->comm, task_pid_nr(current)); + + if (!get_address_stack_frame_info(addr, &offset, &frame_descr, + &frame_pc)) + return; + + pr_err(" and is located at offset %lu in frame:\n", offset); + pr_err(" %pS\n", frame_pc); + + if (!frame_descr) + return; + + print_decoded_frame_descr(frame_descr); +} +#endif /* CONFIG_KASAN_STACK */ + +#define DEFINE_ASAN_REPORT_LOAD(size) \ +void __asan_report_load##size##_noabort(void *addr) \ +{ \ + kasan_report(addr, size, false, _RET_IP_); \ +} \ +EXPORT_SYMBOL(__asan_report_load##size##_noabort) + +#define DEFINE_ASAN_REPORT_STORE(size) \ +void __asan_report_store##size##_noabort(void *addr) \ +{ \ + kasan_report(addr, size, true, _RET_IP_); \ +} \ +EXPORT_SYMBOL(__asan_report_store##size##_noabort) + +DEFINE_ASAN_REPORT_LOAD(1); +DEFINE_ASAN_REPORT_LOAD(2); +DEFINE_ASAN_REPORT_LOAD(4); +DEFINE_ASAN_REPORT_LOAD(8); +DEFINE_ASAN_REPORT_LOAD(16); +DEFINE_ASAN_REPORT_STORE(1); +DEFINE_ASAN_REPORT_STORE(2); +DEFINE_ASAN_REPORT_STORE(4); +DEFINE_ASAN_REPORT_STORE(8); +DEFINE_ASAN_REPORT_STORE(16); + +void __asan_report_load_n_noabort(void *addr, ssize_t size) +{ + kasan_report(addr, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__asan_report_load_n_noabort); + +void __asan_report_store_n_noabort(void *addr, ssize_t size) +{ + kasan_report(addr, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__asan_report_store_n_noabort); diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c new file mode 100644 index 000000000..065e1b2fc --- /dev/null +++ b/mm/kasan/report_hw_tags.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains hardware tag-based KASAN specific error reporting code. + * + * Copyright (c) 2020 Google, Inc. + * Author: Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include + +#include "kasan.h" + +const void *kasan_find_first_bad_addr(const void *addr, size_t size) +{ + /* + * Hardware Tag-Based KASAN only calls this function for normal memory + * accesses, and thus addr points precisely to the first bad address + * with an invalid (and present) memory tag. Therefore: + * 1. Return the address as is without walking memory tags. + * 2. Skip the addr_has_metadata check. + */ + return kasan_reset_tag(addr); +} + +size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache) +{ + size_t size = 0; + int i = 0; + u8 memory_tag; + + /* + * Skip the addr_has_metadata check, as this function only operates on + * slab memory, which must have metadata. + */ + + /* + * The loop below returns 0 for freed objects, for which KASAN cannot + * calculate the allocation size based on the metadata. + */ + while (size < cache->object_size) { + memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE); + if (memory_tag != KASAN_TAG_INVALID) + size += KASAN_GRANULE_SIZE; + else + return size; + i++; + } + + return cache->object_size; +} + +void kasan_metadata_fetch_row(char *buffer, void *row) +{ + int i; + + for (i = 0; i < META_BYTES_PER_ROW; i++) + buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE); +} + +void kasan_print_tags(u8 addr_tag, const void *addr) +{ + u8 memory_tag = hw_get_mem_tag((void *)addr); + + pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", + addr_tag, memory_tag); +} diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c new file mode 100644 index 000000000..689e94f9f --- /dev/null +++ b/mm/kasan/report_sw_tags.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains software tag-based KASAN specific error reporting code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "kasan.h" +#include "../slab.h" + +const void *kasan_find_first_bad_addr(const void *addr, size_t size) +{ + u8 tag = get_tag(addr); + void *p = kasan_reset_tag(addr); + void *end = p + size; + + if (!addr_has_metadata(p)) + return p; + + while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p)) + p += KASAN_GRANULE_SIZE; + + return p; +} + +size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache) +{ + size_t size = 0; + u8 *shadow; + + /* + * Skip the addr_has_metadata check, as this function only operates on + * slab memory, which must have metadata. + */ + + /* + * The loop below returns 0 for freed objects, for which KASAN cannot + * calculate the allocation size based on the metadata. + */ + shadow = (u8 *)kasan_mem_to_shadow(object); + while (size < cache->object_size) { + if (*shadow != KASAN_TAG_INVALID) + size += KASAN_GRANULE_SIZE; + else + return size; + shadow++; + } + + return cache->object_size; +} + +void kasan_metadata_fetch_row(char *buffer, void *row) +{ + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); +} + +void kasan_print_tags(u8 addr_tag, const void *addr) +{ + u8 *shadow = (u8 *)kasan_mem_to_shadow(addr); + + pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow); +} + +#ifdef CONFIG_KASAN_STACK +void kasan_print_address_stack_frame(const void *addr) +{ + if (WARN_ON(!object_is_on_stack(addr))) + return; + + pr_err("The buggy address belongs to stack of task %s/%d\n", + current->comm, task_pid_nr(current)); +} +#endif diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c new file mode 100644 index 000000000..8b8bfdb3c --- /dev/null +++ b/mm/kasan/report_tags.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Copyright (c) 2020 Google, Inc. + */ + +#include + +#include "kasan.h" + +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. + * + * Casting negative numbers to size_t would indeed turn up as + * a large size_t and its value will be larger than ULONG_MAX/2, + * so that this can qualify as out-of-bounds. + */ + if (info->access_addr + info->access_size < info->access_addr) + return "out-of-bounds"; + + 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 = "slab-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/shadow.c b/mm/kasan/shadow.c new file mode 100644 index 000000000..dd772f9d0 --- /dev/null +++ b/mm/kasan/shadow.c @@ -0,0 +1,650 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains KASAN runtime code that manages shadow memory for + * generic and software tag-based KASAN modes. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include "kasan.h" + +bool __kasan_check_read(const volatile void *p, unsigned int size) +{ + return kasan_check_range((void *)p, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__kasan_check_read); + +bool __kasan_check_write(const volatile void *p, unsigned int size) +{ + return kasan_check_range((void *)p, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__kasan_check_write); + +#if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY) +/* + * CONFIG_GENERIC_ENTRY relies on compiler emitted mem*() calls to not be + * instrumented. KASAN enabled toolchains should emit __asan_mem*() functions + * for the sites they want to instrument. + * + * If we have a compiler that can instrument meminstrinsics, never override + * these, so that non-instrumented files can safely consider them as builtins. + */ +#undef memset +void *memset(void *addr, int c, size_t len) +{ + if (!kasan_check_range(addr, len, true, _RET_IP_)) + return NULL; + + return __memset(addr, c, len); +} + +#ifdef __HAVE_ARCH_MEMMOVE +#undef memmove +void *memmove(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range(src, len, false, _RET_IP_) || + !kasan_check_range(dest, len, true, _RET_IP_)) + return NULL; + + return __memmove(dest, src, len); +} +#endif + +#undef memcpy +void *memcpy(void *dest, const void *src, size_t len) +{ + if (!kasan_check_range(src, len, false, _RET_IP_) || + !kasan_check_range(dest, len, true, _RET_IP_)) + return NULL; + + return __memcpy(dest, src, len); +} +#endif + +void *__asan_memset(void *addr, int c, ssize_t len) +{ + if (!kasan_check_range(addr, len, true, _RET_IP_)) + return NULL; + + return __memset(addr, c, len); +} +EXPORT_SYMBOL(__asan_memset); + +#ifdef __HAVE_ARCH_MEMMOVE +void *__asan_memmove(void *dest, const void *src, ssize_t len) +{ + if (!kasan_check_range(src, len, false, _RET_IP_) || + !kasan_check_range(dest, len, true, _RET_IP_)) + return NULL; + + return __memmove(dest, src, len); +} +EXPORT_SYMBOL(__asan_memmove); +#endif + +void *__asan_memcpy(void *dest, const void *src, ssize_t len) +{ + if (!kasan_check_range(src, len, false, _RET_IP_) || + !kasan_check_range(dest, len, true, _RET_IP_)) + return NULL; + + return __memcpy(dest, src, len); +} +EXPORT_SYMBOL(__asan_memcpy); + +#ifdef CONFIG_KASAN_SW_TAGS +void *__hwasan_memset(void *addr, int c, ssize_t len) __alias(__asan_memset); +EXPORT_SYMBOL(__hwasan_memset); +#ifdef __HAVE_ARCH_MEMMOVE +void *__hwasan_memmove(void *dest, const void *src, ssize_t len) __alias(__asan_memmove); +EXPORT_SYMBOL(__hwasan_memmove); +#endif +void *__hwasan_memcpy(void *dest, const void *src, ssize_t len) __alias(__asan_memcpy); +EXPORT_SYMBOL(__hwasan_memcpy); +#endif + +void kasan_poison(const void *addr, size_t size, u8 value, bool init) +{ + void *shadow_start, *shadow_end; + + if (!kasan_arch_is_ready()) + return; + + /* + * Perform shadow offset calculation based on untagged address, as + * some of the callers (e.g. kasan_poison_object_data) pass tagged + * addresses to this function. + */ + addr = kasan_reset_tag(addr); + + /* Skip KFENCE memory if called explicitly outside of sl*b. */ + if (is_kfence_address(addr)) + return; + + if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK)) + return; + if (WARN_ON(size & KASAN_GRANULE_MASK)) + return; + + shadow_start = kasan_mem_to_shadow(addr); + shadow_end = kasan_mem_to_shadow(addr + size); + + __memset(shadow_start, value, shadow_end - shadow_start); +} +EXPORT_SYMBOL(kasan_poison); + +#ifdef CONFIG_KASAN_GENERIC +void kasan_poison_last_granule(const void *addr, size_t size) +{ + if (!kasan_arch_is_ready()) + return; + + if (size & KASAN_GRANULE_MASK) { + u8 *shadow = (u8 *)kasan_mem_to_shadow(addr + size); + *shadow = size & KASAN_GRANULE_MASK; + } +} +#endif + +void kasan_unpoison(const void *addr, size_t size, bool init) +{ + u8 tag = get_tag(addr); + + /* + * Perform shadow offset calculation based on untagged address, as + * some of the callers (e.g. kasan_unpoison_object_data) pass tagged + * addresses to this function. + */ + addr = kasan_reset_tag(addr); + + /* + * Skip KFENCE memory if called explicitly outside of sl*b. Also note + * that calls to ksize(), where size is not a multiple of machine-word + * size, would otherwise poison the invalid portion of the word. + */ + if (is_kfence_address(addr)) + return; + + if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK)) + return; + + /* Unpoison all granules that cover the object. */ + kasan_poison(addr, round_up(size, KASAN_GRANULE_SIZE), tag, false); + + /* Partially poison the last granule for the generic mode. */ + if (IS_ENABLED(CONFIG_KASAN_GENERIC)) + kasan_poison_last_granule(addr, size); +} + +#ifdef CONFIG_MEMORY_HOTPLUG +static bool shadow_mapped(unsigned long addr) +{ + pgd_t *pgd = pgd_offset_k(addr); + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + if (pgd_none(*pgd)) + return false; + p4d = p4d_offset(pgd, addr); + if (p4d_none(*p4d)) + return false; + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return false; + + /* + * We can't use pud_large() or pud_huge(), the first one is + * arch-specific, the last one depends on HUGETLB_PAGE. So let's abuse + * pud_bad(), if pud is bad then it's bad because it's huge. + */ + if (pud_bad(*pud)) + return true; + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return false; + + if (pmd_bad(*pmd)) + return true; + pte = pte_offset_kernel(pmd, addr); + return !pte_none(ptep_get(pte)); +} + +static int __meminit kasan_mem_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct memory_notify *mem_data = data; + unsigned long nr_shadow_pages, start_kaddr, shadow_start; + unsigned long shadow_end, shadow_size; + + nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT; + start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn); + shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr); + shadow_size = nr_shadow_pages << PAGE_SHIFT; + shadow_end = shadow_start + shadow_size; + + if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) || + WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE)) + return NOTIFY_BAD; + + switch (action) { + case MEM_GOING_ONLINE: { + void *ret; + + /* + * If shadow is mapped already than it must have been mapped + * during the boot. This could happen if we onlining previously + * offlined memory. + */ + if (shadow_mapped(shadow_start)) + return NOTIFY_OK; + + ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start, + shadow_end, GFP_KERNEL, + PAGE_KERNEL, VM_NO_GUARD, + pfn_to_nid(mem_data->start_pfn), + __builtin_return_address(0)); + if (!ret) + return NOTIFY_BAD; + + kmemleak_ignore(ret); + return NOTIFY_OK; + } + case MEM_CANCEL_ONLINE: + case MEM_OFFLINE: { + struct vm_struct *vm; + + /* + * shadow_start was either mapped during boot by kasan_init() + * or during memory online by __vmalloc_node_range(). + * In the latter case we can use vfree() to free shadow. + * Non-NULL result of the find_vm_area() will tell us if + * that was the second case. + * + * Currently it's not possible to free shadow mapped + * during boot by kasan_init(). It's because the code + * to do that hasn't been written yet. So we'll just + * leak the memory. + */ + vm = find_vm_area((void *)shadow_start); + if (vm) + vfree((void *)shadow_start); + } + } + + return NOTIFY_OK; +} + +static int __init kasan_memhotplug_init(void) +{ + hotplug_memory_notifier(kasan_mem_notifier, DEFAULT_CALLBACK_PRI); + + return 0; +} + +core_initcall(kasan_memhotplug_init); +#endif + +#ifdef CONFIG_KASAN_VMALLOC + +void __init __weak kasan_populate_early_vm_area_shadow(void *start, + unsigned long size) +{ +} + +static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr, + void *unused) +{ + unsigned long page; + pte_t pte; + + if (likely(!pte_none(ptep_get(ptep)))) + return 0; + + page = __get_free_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE); + pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL); + + spin_lock(&init_mm.page_table_lock); + if (likely(pte_none(ptep_get(ptep)))) { + set_pte_at(&init_mm, addr, ptep, pte); + page = 0; + } + spin_unlock(&init_mm.page_table_lock); + if (page) + free_page(page); + return 0; +} + +int kasan_populate_vmalloc(unsigned long addr, unsigned long size) +{ + unsigned long shadow_start, shadow_end; + int ret; + + if (!kasan_arch_is_ready()) + return 0; + + if (!is_vmalloc_or_module_addr((void *)addr)) + return 0; + + shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr); + shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size); + + /* + * User Mode Linux maps enough shadow memory for all of virtual memory + * at boot, so doesn't need to allocate more on vmalloc, just clear it. + * + * The remaining CONFIG_UML checks in this file exist for the same + * reason. + */ + if (IS_ENABLED(CONFIG_UML)) { + __memset((void *)shadow_start, KASAN_VMALLOC_INVALID, shadow_end - shadow_start); + return 0; + } + + shadow_start = PAGE_ALIGN_DOWN(shadow_start); + shadow_end = PAGE_ALIGN(shadow_end); + + ret = apply_to_page_range(&init_mm, shadow_start, + shadow_end - shadow_start, + kasan_populate_vmalloc_pte, NULL); + if (ret) + return ret; + + flush_cache_vmap(shadow_start, shadow_end); + + /* + * We need to be careful about inter-cpu effects here. Consider: + * + * CPU#0 CPU#1 + * WRITE_ONCE(p, vmalloc(100)); while (x = READ_ONCE(p)) ; + * p[99] = 1; + * + * With compiler instrumentation, that ends up looking like this: + * + * CPU#0 CPU#1 + * // vmalloc() allocates memory + * // let a = area->addr + * // we reach kasan_populate_vmalloc + * // and call kasan_unpoison: + * STORE shadow(a), unpoison_val + * ... + * STORE shadow(a+99), unpoison_val x = LOAD p + * // rest of vmalloc process + * STORE p, a LOAD shadow(x+99) + * + * If there is no barrier between the end of unpoisoning the shadow + * and the store of the result to p, the stores could be committed + * in a different order by CPU#0, and CPU#1 could erroneously observe + * poison in the shadow. + * + * We need some sort of barrier between the stores. + * + * In the vmalloc() case, this is provided by a smp_wmb() in + * clear_vm_uninitialized_flag(). In the per-cpu allocator and in + * get_vm_area() and friends, the caller gets shadow allocated but + * doesn't have any pages mapped into the virtual address space that + * has been reserved. Mapping those pages in will involve taking and + * releasing a page-table lock, which will provide the barrier. + */ + + return 0; +} + +static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr, + void *unused) +{ + unsigned long page; + + page = (unsigned long)__va(pte_pfn(ptep_get(ptep)) << PAGE_SHIFT); + + spin_lock(&init_mm.page_table_lock); + + if (likely(!pte_none(ptep_get(ptep)))) { + pte_clear(&init_mm, addr, ptep); + free_page(page); + } + spin_unlock(&init_mm.page_table_lock); + + return 0; +} + +/* + * Release the backing for the vmalloc region [start, end), which + * lies within the free region [free_region_start, free_region_end). + * + * This can be run lazily, long after the region was freed. It runs + * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap + * infrastructure. + * + * How does this work? + * ------------------- + * + * We have a region that is page aligned, labeled as A. + * That might not map onto the shadow in a way that is page-aligned: + * + * start end + * v v + * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc + * -------- -------- -------- -------- -------- + * | | | | | + * | | | /-------/ | + * \-------\|/------/ |/---------------/ + * ||| || + * |??AAAAAA|AAAAAAAA|AA??????| < shadow + * (1) (2) (3) + * + * First we align the start upwards and the end downwards, so that the + * shadow of the region aligns with shadow page boundaries. In the + * example, this gives us the shadow page (2). This is the shadow entirely + * covered by this allocation. + * + * Then we have the tricky bits. We want to know if we can free the + * partially covered shadow pages - (1) and (3) in the example. For this, + * we are given the start and end of the free region that contains this + * allocation. Extending our previous example, we could have: + * + * free_region_start free_region_end + * | start end | + * v v v v + * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc + * -------- -------- -------- -------- -------- + * | | | | | + * | | | /-------/ | + * \-------\|/------/ |/---------------/ + * ||| || + * |FFAAAAAA|AAAAAAAA|AAF?????| < shadow + * (1) (2) (3) + * + * Once again, we align the start of the free region up, and the end of + * the free region down so that the shadow is page aligned. So we can free + * page (1) - we know no allocation currently uses anything in that page, + * because all of it is in the vmalloc free region. But we cannot free + * page (3), because we can't be sure that the rest of it is unused. + * + * We only consider pages that contain part of the original region for + * freeing: we don't try to free other pages from the free region or we'd + * end up trying to free huge chunks of virtual address space. + * + * Concurrency + * ----------- + * + * How do we know that we're not freeing a page that is simultaneously + * being used for a fresh allocation in kasan_populate_vmalloc(_pte)? + * + * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running + * at the same time. While we run under free_vmap_area_lock, the population + * code does not. + * + * free_vmap_area_lock instead operates to ensure that the larger range + * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and + * the per-cpu region-finding algorithm both run under free_vmap_area_lock, + * no space identified as free will become used while we are running. This + * means that so long as we are careful with alignment and only free shadow + * pages entirely covered by the free region, we will not run in to any + * trouble - any simultaneous allocations will be for disjoint regions. + */ +void kasan_release_vmalloc(unsigned long start, unsigned long end, + unsigned long free_region_start, + unsigned long free_region_end) +{ + void *shadow_start, *shadow_end; + unsigned long region_start, region_end; + unsigned long size; + + if (!kasan_arch_is_ready()) + return; + + region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE); + region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE); + + free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE); + + if (start != region_start && + free_region_start < region_start) + region_start -= KASAN_MEMORY_PER_SHADOW_PAGE; + + free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE); + + if (end != region_end && + free_region_end > region_end) + region_end += KASAN_MEMORY_PER_SHADOW_PAGE; + + shadow_start = kasan_mem_to_shadow((void *)region_start); + shadow_end = kasan_mem_to_shadow((void *)region_end); + + if (shadow_end > shadow_start) { + size = shadow_end - shadow_start; + if (IS_ENABLED(CONFIG_UML)) { + __memset(shadow_start, KASAN_SHADOW_INIT, shadow_end - shadow_start); + return; + } + apply_to_existing_page_range(&init_mm, + (unsigned long)shadow_start, + size, kasan_depopulate_vmalloc_pte, + NULL); + flush_tlb_kernel_range((unsigned long)shadow_start, + (unsigned long)shadow_end); + } +} + +void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, + kasan_vmalloc_flags_t flags) +{ + /* + * Software KASAN modes unpoison both VM_ALLOC and non-VM_ALLOC + * mappings, so the KASAN_VMALLOC_VM_ALLOC flag is ignored. + * Software KASAN modes can't optimize zeroing memory by combining it + * with setting memory tags, so the KASAN_VMALLOC_INIT flag is ignored. + */ + + if (!kasan_arch_is_ready()) + return (void *)start; + + if (!is_vmalloc_or_module_addr(start)) + return (void *)start; + + /* + * Don't tag executable memory with the tag-based mode. + * The kernel doesn't tolerate having the PC register tagged. + */ + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) && + !(flags & KASAN_VMALLOC_PROT_NORMAL)) + return (void *)start; + + start = set_tag(start, kasan_random_tag()); + kasan_unpoison(start, size, false); + return (void *)start; +} + +/* + * Poison the shadow for a vmalloc region. Called as part of the + * freeing process at the time the region is freed. + */ +void __kasan_poison_vmalloc(const void *start, unsigned long size) +{ + if (!kasan_arch_is_ready()) + return; + + if (!is_vmalloc_or_module_addr(start)) + return; + + size = round_up(size, KASAN_GRANULE_SIZE); + kasan_poison(start, size, KASAN_VMALLOC_INVALID, false); +} + +#else /* CONFIG_KASAN_VMALLOC */ + +int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask) +{ + void *ret; + size_t scaled_size; + size_t shadow_size; + unsigned long shadow_start; + + shadow_start = (unsigned long)kasan_mem_to_shadow(addr); + scaled_size = (size + KASAN_GRANULE_SIZE - 1) >> + KASAN_SHADOW_SCALE_SHIFT; + shadow_size = round_up(scaled_size, PAGE_SIZE); + + if (WARN_ON(!PAGE_ALIGNED(shadow_start))) + return -EINVAL; + + if (IS_ENABLED(CONFIG_UML)) { + __memset((void *)shadow_start, KASAN_SHADOW_INIT, shadow_size); + return 0; + } + + ret = __vmalloc_node_range(shadow_size, 1, shadow_start, + shadow_start + shadow_size, + GFP_KERNEL, + PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, + __builtin_return_address(0)); + + if (ret) { + struct vm_struct *vm = find_vm_area(addr); + __memset(ret, KASAN_SHADOW_INIT, shadow_size); + vm->flags |= VM_KASAN; + kmemleak_ignore(ret); + + if (vm->flags & VM_DEFER_KMEMLEAK) + kmemleak_vmalloc(vm, size, gfp_mask); + + return 0; + } + + return -ENOMEM; +} + +void kasan_free_module_shadow(const struct vm_struct *vm) +{ + if (IS_ENABLED(CONFIG_UML)) + return; + + if (vm->flags & VM_KASAN) + vfree(kasan_mem_to_shadow(vm->addr)); +} + +#endif diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c new file mode 100644 index 000000000..220b5d4c6 --- /dev/null +++ b/mm/kasan/sw_tags.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains core software tag-based KASAN code. + * + * Copyright (c) 2018 Google, Inc. + * Author: Andrey Konovalov + */ + +#define pr_fmt(fmt) "kasan: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kasan.h" +#include "../slab.h" + +static DEFINE_PER_CPU(u32, prng_state); + +void __init kasan_init_sw_tags(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + per_cpu(prng_state, cpu) = (u32)get_cycles(); + + kasan_init_tags(); + + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n", + kasan_stack_collection_enabled() ? "on" : "off"); +} + +/* + * If a preemption happens between this_cpu_read and this_cpu_write, the only + * side effect is that we'll give a few allocated in different contexts objects + * the same tag. Since tag-based KASAN is meant to be used a probabilistic + * bug-detection debug feature, this doesn't have significant negative impact. + * + * Ideally the tags use strong randomness to prevent any attempts to predict + * them during explicit exploit attempts. But strong randomness is expensive, + * and we did an intentional trade-off to use a PRNG. This non-atomic RMW + * sequence has in fact positive effect, since interrupts that randomly skew + * PRNG at unpredictable points do only good. + */ +u8 kasan_random_tag(void) +{ + u32 state = this_cpu_read(prng_state); + + state = 1664525 * state + 1013904223; + this_cpu_write(prng_state, state); + + return (u8)(state % (KASAN_TAG_MAX + 1)); +} + +bool kasan_check_range(const void *addr, size_t size, bool write, + unsigned long ret_ip) +{ + u8 tag; + u8 *shadow_first, *shadow_last, *shadow; + void *untagged_addr; + + if (unlikely(size == 0)) + return true; + + if (unlikely(addr + size < addr)) + return !kasan_report(addr, size, write, ret_ip); + + tag = get_tag((const void *)addr); + + /* + * Ignore accesses for pointers tagged with 0xff (native kernel + * pointer tag) to suppress false positives caused by kmap. + * + * Some kernel code was written to account for archs that don't keep + * high memory mapped all the time, but rather map and unmap particular + * pages when needed. Instead of storing a pointer to the kernel memory, + * this code saves the address of the page structure and offset within + * that page for later use. Those pages are then mapped and unmapped + * with kmap/kunmap when necessary and virt_to_page is used to get the + * virtual address of the page. For arm64 (that keeps the high memory + * mapped all the time), kmap is turned into a page_address call. + + * The issue is that with use of the page_address + virt_to_page + * sequence the top byte value of the original pointer gets lost (gets + * set to KASAN_TAG_KERNEL (0xFF)). + */ + if (tag == KASAN_TAG_KERNEL) + return true; + + untagged_addr = kasan_reset_tag((const void *)addr); + if (unlikely(!addr_has_metadata(untagged_addr))) + return !kasan_report(addr, size, write, ret_ip); + shadow_first = kasan_mem_to_shadow(untagged_addr); + shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1); + for (shadow = shadow_first; shadow <= shadow_last; shadow++) { + if (*shadow != tag) { + return !kasan_report(addr, size, write, ret_ip); + } + } + + return true; +} + +bool kasan_byte_accessible(const void *addr) +{ + u8 tag = get_tag(addr); + void *untagged_addr = kasan_reset_tag(addr); + u8 shadow_byte; + + if (!addr_has_metadata(untagged_addr)) + return false; + + shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(untagged_addr)); + return tag == KASAN_TAG_KERNEL || tag == shadow_byte; +} + +#define DEFINE_HWASAN_LOAD_STORE(size) \ + void __hwasan_load##size##_noabort(void *addr) \ + { \ + kasan_check_range(addr, size, false, _RET_IP_); \ + } \ + EXPORT_SYMBOL(__hwasan_load##size##_noabort); \ + void __hwasan_store##size##_noabort(void *addr) \ + { \ + kasan_check_range(addr, size, true, _RET_IP_); \ + } \ + EXPORT_SYMBOL(__hwasan_store##size##_noabort) + +DEFINE_HWASAN_LOAD_STORE(1); +DEFINE_HWASAN_LOAD_STORE(2); +DEFINE_HWASAN_LOAD_STORE(4); +DEFINE_HWASAN_LOAD_STORE(8); +DEFINE_HWASAN_LOAD_STORE(16); + +void __hwasan_loadN_noabort(void *addr, ssize_t size) +{ + kasan_check_range(addr, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__hwasan_loadN_noabort); + +void __hwasan_storeN_noabort(void *addr, ssize_t size) +{ + kasan_check_range(addr, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__hwasan_storeN_noabort); + +void __hwasan_tag_memory(void *addr, u8 tag, ssize_t size) +{ + kasan_poison(addr, size, tag, false); +} +EXPORT_SYMBOL(__hwasan_tag_memory); + +void kasan_tag_mismatch(void *addr, unsigned long access_info, + unsigned long ret_ip) +{ + kasan_report(addr, 1 << (access_info & 0xf), access_info & 0x10, + ret_ip); +} diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c new file mode 100644 index 000000000..7dcfe341d --- /dev/null +++ b/mm/kasan/tags.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains common tag-based KASAN code. + * + * Copyright (c) 2018 Google, Inc. + * Copyright (c) 2020 Google, Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kasan.h" +#include "../slab.h" + +#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); + +/* 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; + + 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); + +/* kasan.stack_ring_size= */ +static int __init early_kasan_flag_stack_ring_size(char *arg) +{ + if (!arg) + return -EINVAL; + + 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; + } + + 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); + } +} + +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); + + 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, 0, true); +} -- cgit v1.2.3