diff options
| -rw-r--r-- | mm/kfence/core.c | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index da0f5b6f5744..4f79ec720752 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -596,7 +596,7 @@ static void rcu_guarded_free(struct rcu_head *h) static unsigned long kfence_init_pool(void) { unsigned long addr, start_pfn; - int i; + int i, rand; if (!arch_kfence_init_pool()) return (unsigned long)__kfence_pool; @@ -647,13 +647,27 @@ static unsigned long kfence_init_pool(void) INIT_LIST_HEAD(&meta->list); raw_spin_lock_init(&meta->lock); meta->state = KFENCE_OBJECT_UNUSED; - meta->addr = addr; /* Initialize for validation in metadata_to_pageaddr(). */ - list_add_tail(&meta->list, &kfence_freelist); + /* Use addr to randomize the freelist. */ + meta->addr = i; /* Protect the right redzone. */ - if (unlikely(!kfence_protect(addr + PAGE_SIZE))) + if (unlikely(!kfence_protect(addr + 2 * i * PAGE_SIZE + PAGE_SIZE))) goto reset_slab; + } + + for (i = CONFIG_KFENCE_NUM_OBJECTS; i > 0; i--) { + rand = get_random_u32_below(i); + swap(kfence_metadata_init[i - 1].addr, kfence_metadata_init[rand].addr); + } + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + struct kfence_metadata *meta_1 = &kfence_metadata_init[i]; + struct kfence_metadata *meta_2 = &kfence_metadata_init[meta_1->addr]; + + list_add_tail(&meta_2->list, &kfence_freelist); + } + for (i = 0; i < CONFIG_KFENCE_NUM_OBJECTS; i++) { + kfence_metadata_init[i].addr = addr; addr += 2 * PAGE_SIZE; } @@ -666,6 +680,7 @@ static unsigned long kfence_init_pool(void) return 0; reset_slab: + addr += 2 * i * PAGE_SIZE; for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { struct page *page; |