diff options
Diffstat (limited to 'mm/kfence')
-rw-r--r-- | mm/kfence/core.c | 21 | ||||
-rw-r--r-- | mm/kfence/kfence.h | 21 | ||||
-rw-r--r-- | mm/kfence/report.c | 47 |
3 files changed, 68 insertions, 21 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index a203747ad2c0..9b2b5f56f4ae 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -231,27 +231,6 @@ static bool kfence_unprotect(unsigned long addr) return !KFENCE_WARN_ON(!kfence_protect_page(ALIGN_DOWN(addr, PAGE_SIZE), false)); } -static inline struct kfence_metadata *addr_to_metadata(unsigned long addr) -{ - long index; - - /* The checks do not affect performance; only called from slow-paths. */ - - if (!is_kfence_address((void *)addr)) - return NULL; - - /* - * May be an invalid index if called with an address at the edge of - * __kfence_pool, in which case we would report an "invalid access" - * error. - */ - index = (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; - if (index < 0 || index >= CONFIG_KFENCE_NUM_OBJECTS) - return NULL; - - return &kfence_metadata[index]; -} - static inline unsigned long metadata_to_pageaddr(const struct kfence_metadata *meta) { unsigned long offset = (meta - kfence_metadata + 1) * PAGE_SIZE * 2; diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h index 9a6c4b1b12a8..600f2e2431d6 100644 --- a/mm/kfence/kfence.h +++ b/mm/kfence/kfence.h @@ -96,6 +96,27 @@ struct kfence_metadata { extern struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS]; +static inline struct kfence_metadata *addr_to_metadata(unsigned long addr) +{ + long index; + + /* The checks do not affect performance; only called from slow-paths. */ + + if (!is_kfence_address((void *)addr)) + return NULL; + + /* + * May be an invalid index if called with an address at the edge of + * __kfence_pool, in which case we would report an "invalid access" + * error. + */ + index = (addr - (unsigned long)__kfence_pool) / (PAGE_SIZE * 2) - 1; + if (index < 0 || index >= CONFIG_KFENCE_NUM_OBJECTS) + return NULL; + + return &kfence_metadata[index]; +} + /* KFENCE error types for report generation. */ enum kfence_error_type { KFENCE_ERROR_OOB, /* Detected a out-of-bounds access. */ diff --git a/mm/kfence/report.c b/mm/kfence/report.c index f93a7b2a338b..f5a6d8ba3e21 100644 --- a/mm/kfence/report.c +++ b/mm/kfence/report.c @@ -273,3 +273,50 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r /* We encountered a memory safety error, taint the kernel! */ add_taint(TAINT_BAD_PAGE, LOCKDEP_STILL_OK); } + +#ifdef CONFIG_PRINTK +static void kfence_to_kp_stack(const struct kfence_track *track, void **kp_stack) +{ + int i, j; + + i = get_stack_skipnr(track->stack_entries, track->num_stack_entries, NULL); + for (j = 0; i < track->num_stack_entries && j < KS_ADDRS_COUNT; ++i, ++j) + kp_stack[j] = (void *)track->stack_entries[i]; + if (j < KS_ADDRS_COUNT) + kp_stack[j] = NULL; +} + +bool __kfence_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) +{ + struct kfence_metadata *meta = addr_to_metadata((unsigned long)object); + unsigned long flags; + + if (!meta) + return false; + + /* + * If state is UNUSED at least show the pointer requested; the rest + * would be garbage data. + */ + kpp->kp_ptr = object; + + /* Requesting info an a never-used object is almost certainly a bug. */ + if (WARN_ON(meta->state == KFENCE_OBJECT_UNUSED)) + return true; + + raw_spin_lock_irqsave(&meta->lock, flags); + + kpp->kp_slab = slab; + kpp->kp_slab_cache = meta->cache; + kpp->kp_objp = (void *)meta->addr; + kfence_to_kp_stack(&meta->alloc_track, kpp->kp_stack); + if (meta->state == KFENCE_OBJECT_FREED) + kfence_to_kp_stack(&meta->free_track, kpp->kp_free_stack); + /* get_stack_skipnr() ensures the first entry is outside allocator. */ + kpp->kp_ret = kpp->kp_stack[0]; + + raw_spin_unlock_irqrestore(&meta->lock, flags); + + return true; +} +#endif |