diff options
Diffstat (limited to 'mm/kasan/kasan.c')
| -rw-r--r-- | mm/kasan/kasan.c | 570 |
1 files changed, 2 insertions, 568 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 55deff17a4d9..44ec228de0a2 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -1,5 +1,5 @@ /* - * This file contains shadow memory manipulation code. + * This file contains core KASAN code. * * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> @@ -40,82 +40,6 @@ #include "kasan.h" #include "../slab.h" -void kasan_enable_current(void) -{ - current->kasan_depth++; -} - -void kasan_disable_current(void) -{ - current->kasan_depth--; -} - -/* - * Poisons the shadow memory for 'size' bytes starting from 'addr'. - * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE. - */ -static void kasan_poison_shadow(const void *address, size_t size, u8 value) -{ - void *shadow_start, *shadow_end; - - shadow_start = kasan_mem_to_shadow(address); - shadow_end = kasan_mem_to_shadow(address + size); - - memset(shadow_start, value, shadow_end - shadow_start); -} - -void kasan_unpoison_shadow(const void *address, size_t size) -{ - kasan_poison_shadow(address, size, 0); - - if (size & KASAN_SHADOW_MASK) { - u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size); - *shadow = size & KASAN_SHADOW_MASK; - } -} - -static void __kasan_unpoison_stack(struct task_struct *task, const void *sp) -{ - void *base = task_stack_page(task); - size_t size = sp - base; - - kasan_unpoison_shadow(base, size); -} - -/* Unpoison the entire stack for a task. */ -void kasan_unpoison_task_stack(struct task_struct *task) -{ - __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE); -} - -/* 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_shadow(base, watermark - base); -} - -/* - * Clear all poison for the region between the current SP and a provided - * watermark value, as is sometimes required prior to hand-crafted asm function - * returns in the middle of functions. - */ -void kasan_unpoison_stack_above_sp_to(const void *watermark) -{ - const void *sp = __builtin_frame_address(0); - size_t size = watermark - sp; - - if (WARN_ON(sp > watermark)) - return; - kasan_unpoison_shadow(sp, size); -} - /* * All functions below always inlined so compiler could * perform better optimizations in each of __asan_loadX/__assn_storeX @@ -260,121 +184,12 @@ static __always_inline void check_memory_region_inline(unsigned long addr, kasan_report(addr, size, write, ret_ip); } -static void check_memory_region(unsigned long addr, - size_t size, bool write, +void check_memory_region(unsigned long addr, size_t size, bool write, unsigned long ret_ip) { check_memory_region_inline(addr, size, write, ret_ip); } -void kasan_check_read(const volatile void *p, unsigned int size) -{ - check_memory_region((unsigned long)p, size, false, _RET_IP_); -} -EXPORT_SYMBOL(kasan_check_read); - -void kasan_check_write(const volatile void *p, unsigned int size) -{ - check_memory_region((unsigned long)p, size, true, _RET_IP_); -} -EXPORT_SYMBOL(kasan_check_write); - -#undef memset -void *memset(void *addr, int c, size_t len) -{ - check_memory_region((unsigned long)addr, len, true, _RET_IP_); - - return __memset(addr, c, len); -} - -#undef memmove -void *memmove(void *dest, const void *src, size_t len) -{ - check_memory_region((unsigned long)src, len, false, _RET_IP_); - check_memory_region((unsigned long)dest, len, true, _RET_IP_); - - return __memmove(dest, src, len); -} - -#undef memcpy -void *memcpy(void *dest, const void *src, size_t len) -{ - check_memory_region((unsigned long)src, len, false, _RET_IP_); - check_memory_region((unsigned long)dest, len, true, _RET_IP_); - - return __memcpy(dest, src, len); -} - -void kasan_alloc_pages(struct page *page, unsigned int order) -{ - if (likely(!PageHighMem(page))) - kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order); -} - -void kasan_free_pages(struct page *page, unsigned int order) -{ - if (likely(!PageHighMem(page))) - kasan_poison_shadow(page_address(page), - PAGE_SIZE << order, - KASAN_FREE_PAGE); -} - -/* - * Adaptive redzone policy taken from the userspace AddressSanitizer runtime. - * For larger allocations larger redzones are used. - */ -static 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 orig_size = *size; - int redzone_adjust; - - /* Add alloc meta. */ - cache->kasan_info.alloc_meta_offset = *size; - *size += sizeof(struct kasan_alloc_meta); - - /* Add free meta. */ - if (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor || - cache->object_size < sizeof(struct kasan_free_meta)) { - cache->kasan_info.free_meta_offset = *size; - *size += sizeof(struct kasan_free_meta); - } - redzone_adjust = optimal_redzone(cache->object_size) - - (*size - cache->object_size); - - if (redzone_adjust > 0) - *size += redzone_adjust; - - *size = min_t(unsigned int, KMALLOC_MAX_SIZE, - max(*size, cache->object_size + - optimal_redzone(cache->object_size))); - - /* - * If the metadata doesn't fit, don't enable KASAN at all. - */ - if (*size <= cache->kasan_info.alloc_meta_offset || - *size <= cache->kasan_info.free_meta_offset) { - cache->kasan_info.alloc_meta_offset = 0; - cache->kasan_info.free_meta_offset = 0; - *size = orig_size; - return; - } - - *flags |= SLAB_KASAN; -} - void kasan_cache_shrink(struct kmem_cache *cache) { quarantine_remove_cache(cache); @@ -386,277 +201,6 @@ void kasan_cache_shutdown(struct kmem_cache *cache) quarantine_remove_cache(cache); } -size_t kasan_metadata_size(struct kmem_cache *cache) -{ - return (cache->kasan_info.alloc_meta_offset ? - sizeof(struct kasan_alloc_meta) : 0) + - (cache->kasan_info.free_meta_offset ? - sizeof(struct kasan_free_meta) : 0); -} - -void kasan_poison_slab(struct page *page) -{ - kasan_poison_shadow(page_address(page), - PAGE_SIZE << compound_order(page), - KASAN_KMALLOC_REDZONE); -} - -void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) -{ - kasan_unpoison_shadow(object, cache->object_size); -} - -void kasan_poison_object_data(struct kmem_cache *cache, void *object) -{ - kasan_poison_shadow(object, - round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE), - KASAN_KMALLOC_REDZONE); -} - -static inline int in_irqentry_text(unsigned long ptr) -{ - return (ptr >= (unsigned long)&__irqentry_text_start && - ptr < (unsigned long)&__irqentry_text_end) || - (ptr >= (unsigned long)&__softirqentry_text_start && - ptr < (unsigned long)&__softirqentry_text_end); -} - -static inline void filter_irq_stacks(struct stack_trace *trace) -{ - int i; - - if (!trace->nr_entries) - return; - for (i = 0; i < trace->nr_entries; i++) - if (in_irqentry_text(trace->entries[i])) { - /* Include the irqentry function into the stack. */ - trace->nr_entries = i + 1; - break; - } -} - -static inline depot_stack_handle_t save_stack(gfp_t flags) -{ - unsigned long entries[KASAN_STACK_DEPTH]; - struct stack_trace trace = { - .nr_entries = 0, - .entries = entries, - .max_entries = KASAN_STACK_DEPTH, - .skip = 0 - }; - - save_stack_trace(&trace); - filter_irq_stacks(&trace); - if (trace.nr_entries != 0 && - trace.entries[trace.nr_entries-1] == ULONG_MAX) - trace.nr_entries--; - - return depot_save_stack(&trace, flags); -} - -static inline void set_track(struct kasan_track *track, gfp_t flags) -{ - track->pid = current->pid; - track->stack = save_stack(flags); -} - -struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, - const void *object) -{ - BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32); - return (void *)object + cache->kasan_info.alloc_meta_offset; -} - -struct kasan_free_meta *get_free_info(struct kmem_cache *cache, - const void *object) -{ - BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); - return (void *)object + cache->kasan_info.free_meta_offset; -} - -void *kasan_init_slab_obj(struct kmem_cache *cache, const void *object) -{ - struct kasan_alloc_meta *alloc_info; - - if (!(cache->flags & SLAB_KASAN)) - return (void *)object; - - alloc_info = get_alloc_info(cache, object); - __memset(alloc_info, 0, sizeof(*alloc_info)); - - return (void *)object; -} - -void *kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags) -{ - return kasan_kmalloc(cache, object, cache->object_size, flags); -} - -static bool __kasan_slab_free(struct kmem_cache *cache, void *object, - unsigned long ip, bool quarantine) -{ - s8 shadow_byte; - unsigned long rounded_up_size; - - if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) != - object)) { - kasan_report_invalid_free(object, ip); - return true; - } - - /* RCU slabs could be legally used after free within the RCU period */ - if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU)) - return false; - - shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object)); - if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) { - kasan_report_invalid_free(object, ip); - return true; - } - - rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE); - kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); - - if (!quarantine || unlikely(!(cache->flags & SLAB_KASAN))) - return false; - - set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT); - quarantine_put(get_free_info(cache, object), cache); - return true; -} - -bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) -{ - return __kasan_slab_free(cache, object, ip, true); -} - -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)) - quarantine_reduce(); - - if (unlikely(object == NULL)) - return NULL; - - redzone_start = round_up((unsigned long)(object + size), - KASAN_SHADOW_SCALE_SIZE); - redzone_end = round_up((unsigned long)object + cache->object_size, - KASAN_SHADOW_SCALE_SIZE); - - kasan_unpoison_shadow(object, size); - kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, - KASAN_KMALLOC_REDZONE); - - if (cache->flags & SLAB_KASAN) - set_track(&get_alloc_info(cache, object)->alloc_track, flags); - - return (void *)object; -} -EXPORT_SYMBOL(kasan_kmalloc); - -void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) -{ - struct page *page; - unsigned long redzone_start; - unsigned long redzone_end; - - if (gfpflags_allow_blocking(flags)) - quarantine_reduce(); - - if (unlikely(ptr == NULL)) - return NULL; - - page = virt_to_page(ptr); - redzone_start = round_up((unsigned long)(ptr + size), - KASAN_SHADOW_SCALE_SIZE); - redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page)); - - kasan_unpoison_shadow(ptr, size); - kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, - KASAN_PAGE_REDZONE); - - return (void *)ptr; -} - -void *kasan_krealloc(const void *object, size_t size, gfp_t flags) -{ - struct page *page; - - if (unlikely(object == ZERO_SIZE_PTR)) - return ZERO_SIZE_PTR; - - page = virt_to_head_page(object); - - if (unlikely(!PageSlab(page))) - return kasan_kmalloc_large(object, size, flags); - else - return kasan_kmalloc(page->slab_cache, object, size, flags); -} - -void kasan_poison_kfree(void *ptr, unsigned long ip) -{ - struct page *page; - - page = virt_to_head_page(ptr); - - if (unlikely(!PageSlab(page))) { - if (ptr != page_address(page)) { - kasan_report_invalid_free(ptr, ip); - return; - } - kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), - KASAN_FREE_PAGE); - } else { - __kasan_slab_free(page->slab_cache, ptr, ip, false); - } -} - -void kasan_kfree_large(void *ptr, unsigned long ip) -{ - if (ptr != page_address(virt_to_head_page(ptr))) - kasan_report_invalid_free(ptr, ip); - /* The object will be poisoned by page_alloc. */ -} - -int kasan_module_alloc(void *addr, size_t size) -{ - 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_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT; - shadow_size = round_up(scaled_size, PAGE_SIZE); - - if (WARN_ON(!PAGE_ALIGNED(shadow_start))) - return -EINVAL; - - ret = __vmalloc_node_range(shadow_size, 1, shadow_start, - shadow_start + shadow_size, - GFP_KERNEL | __GFP_ZERO, - PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, - __builtin_return_address(0)); - - if (ret) { - find_vm_area(addr)->flags |= VM_KASAN; - kmemleak_ignore(ret); - return 0; - } - - return -ENOMEM; -} - -void kasan_free_shadow(const struct vm_struct *vm) -{ - if (vm->flags & VM_KASAN) - vfree(kasan_mem_to_shadow(vm->addr)); -} - static void register_global(struct kasan_global *global) { size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE); @@ -797,113 +341,3 @@ DEFINE_ASAN_SET_SHADOW(f2); DEFINE_ASAN_SET_SHADOW(f3); DEFINE_ASAN_SET_SHADOW(f5); DEFINE_ASAN_SET_SHADOW(f8); - -#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(*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_SHADOW_SCALE_SIZE) || - WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT))) - 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, 0); - - return 0; -} - -core_initcall(kasan_memhotplug_init); -#endif |