diff options
Diffstat (limited to 'mm/kasan/kasan.c')
| -rw-r--r-- | mm/kasan/kasan.c | 162 |
1 files changed, 154 insertions, 8 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 1ad20ade8..38f1dd79a 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -17,7 +17,9 @@ #define DISABLE_BRANCH_PROFILING #include <linux/export.h> +#include <linux/interrupt.h> #include <linux/init.h> +#include <linux/kasan.h> #include <linux/kernel.h> #include <linux/kmemleak.h> #include <linux/linkage.h> @@ -32,7 +34,6 @@ #include <linux/string.h> #include <linux/types.h> #include <linux/vmalloc.h> -#include <linux/kasan.h> #include "kasan.h" #include "../slab.h" @@ -334,6 +335,59 @@ void kasan_free_pages(struct page *page, unsigned int order) KASAN_FREE_PAGE); } +#ifdef CONFIG_SLAB +/* + * Adaptive redzone policy taken from the userspace AddressSanitizer runtime. + * For larger allocations larger redzones are used. + */ +static size_t optimal_redzone(size_t object_size) +{ + int rz = + 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; + return rz; +} + +void kasan_cache_create(struct kmem_cache *cache, size_t *size, + unsigned long *flags) +{ + int redzone_adjust; + /* Make sure the adjusted size is still less than + * KMALLOC_MAX_CACHE_SIZE. + * TODO: this check is only useful for SLAB, but not SLUB. We'll need + * to skip it for SLUB when it starts using kasan_cache_create(). + */ + if (*size > KMALLOC_MAX_CACHE_SIZE - + sizeof(struct kasan_alloc_meta) - + sizeof(struct kasan_free_meta)) + return; + *flags |= SLAB_KASAN; + /* Add alloc meta. */ + cache->kasan_info.alloc_meta_offset = *size; + *size += sizeof(struct kasan_alloc_meta); + + /* Add free meta. */ + if (cache->flags & SLAB_DESTROY_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(KMALLOC_MAX_CACHE_SIZE, + max(*size, + cache->object_size + + optimal_redzone(cache->object_size))); +} +#endif + void kasan_poison_slab(struct page *page) { kasan_poison_shadow(page_address(page), @@ -351,11 +405,81 @@ 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); +#ifdef CONFIG_SLAB + if (cache->flags & SLAB_KASAN) { + struct kasan_alloc_meta *alloc_info = + get_alloc_info(cache, object); + alloc_info->state = KASAN_STATE_INIT; + } +#endif } -void kasan_slab_alloc(struct kmem_cache *cache, void *object) +#ifdef CONFIG_SLAB +static inline int in_irqentry_text(unsigned long ptr) { - kasan_kmalloc(cache, object, cache->object_size); + 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; +} +#endif + +void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags) +{ + kasan_kmalloc(cache, object, cache->object_size, flags); } void kasan_slab_free(struct kmem_cache *cache, void *object) @@ -367,10 +491,22 @@ void kasan_slab_free(struct kmem_cache *cache, void *object) if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU)) return; +#ifdef CONFIG_SLAB + if (cache->flags & SLAB_KASAN) { + struct kasan_free_meta *free_info = + get_free_info(cache, object); + struct kasan_alloc_meta *alloc_info = + get_alloc_info(cache, object); + alloc_info->state = KASAN_STATE_FREE; + set_track(&free_info->track, GFP_NOWAIT); + } +#endif + kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); } -void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size) +void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size, + gfp_t flags) { unsigned long redzone_start; unsigned long redzone_end; @@ -386,10 +522,20 @@ void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size) kasan_unpoison_shadow(object, size); kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, KASAN_KMALLOC_REDZONE); +#ifdef CONFIG_SLAB + if (cache->flags & SLAB_KASAN) { + struct kasan_alloc_meta *alloc_info = + get_alloc_info(cache, object); + + alloc_info->state = KASAN_STATE_ALLOC; + alloc_info->alloc_size = size; + set_track(&alloc_info->track, flags); + } +#endif } EXPORT_SYMBOL(kasan_kmalloc); -void kasan_kmalloc_large(const void *ptr, size_t size) +void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) { struct page *page; unsigned long redzone_start; @@ -408,7 +554,7 @@ void kasan_kmalloc_large(const void *ptr, size_t size) KASAN_PAGE_REDZONE); } -void kasan_krealloc(const void *object, size_t size) +void kasan_krealloc(const void *object, size_t size, gfp_t flags) { struct page *page; @@ -418,9 +564,9 @@ void kasan_krealloc(const void *object, size_t size) page = virt_to_head_page(object); if (unlikely(!PageSlab(page))) - kasan_kmalloc_large(object, size); + kasan_kmalloc_large(object, size, flags); else - kasan_kmalloc(page->slab_cache, object, size); + kasan_kmalloc(page->slab_cache, object, size, flags); } void kasan_kfree(void *ptr) |