/* * * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <a.ryabinin@samsung.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #define pr_fmt(fmt) "kasan test: %s " fmt, __func__ #include <linux/delay.h> #include <linux/kernel.h> #include <linux/mman.h> #include <linux/mm.h> #include <linux/printk.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/uaccess.h> #include <linux/module.h> #include <linux/kasan.h> /* * Note: test functions are marked noinline so that their names appear in * reports. */ static noinline void __init kmalloc_oob_right(void) { char *ptr; size_t size = 123; pr_info("out-of-bounds to right\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } ptr[size] = 'x'; kfree(ptr); } static noinline void __init kmalloc_oob_left(void) { char *ptr; size_t size = 15; pr_info("out-of-bounds to left\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } *ptr = *(ptr - 1); kfree(ptr); } static noinline void __init kmalloc_node_oob_right(void) { char *ptr; size_t size = 4096; pr_info("kmalloc_node(): out-of-bounds to right\n"); ptr = kmalloc_node(size, GFP_KERNEL, 0); if (!ptr) { pr_err("Allocation failed\n"); return; } ptr[size] = 0; kfree(ptr); } #ifdef CONFIG_SLUB static noinline void __init kmalloc_pagealloc_oob_right(void) { char *ptr; size_t size = KMALLOC_MAX_CACHE_SIZE + 10; /* Allocate a chunk that does not fit into a SLUB cache to trigger * the page allocator fallback. */ pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } ptr[size] = 0; kfree(ptr); } #endif static noinline void __init kmalloc_large_oob_right(void) { 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. */ pr_info("kmalloc large allocation: out-of-bounds to right\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } ptr[size] = 0; kfree(ptr); } static noinline void __init kmalloc_oob_krealloc_more(void) { char *ptr1, *ptr2; size_t size1 = 17; size_t size2 = 19; pr_info("out-of-bounds after krealloc more\n"); ptr1 = kmalloc(size1, GFP_KERNEL); ptr2 = krealloc(ptr1, size2, GFP_KERNEL); if (!ptr1 || !ptr2) { pr_err("Allocation failed\n"); kfree(ptr1); return; } ptr2[size2] = 'x'; kfree(ptr2); } static noinline void __init kmalloc_oob_krealloc_less(void) { char *ptr1, *ptr2; size_t size1 = 17; size_t size2 = 15; pr_info("out-of-bounds after krealloc less\n"); ptr1 = kmalloc(size1, GFP_KERNEL); ptr2 = krealloc(ptr1, size2, GFP_KERNEL); if (!ptr1 || !ptr2) { pr_err("Allocation failed\n"); kfree(ptr1); return; } ptr2[size2] = 'x'; kfree(ptr2); } static noinline void __init kmalloc_oob_16(void) { struct { u64 words[2]; } *ptr1, *ptr2; pr_info("kmalloc out-of-bounds for 16-bytes access\n"); ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); if (!ptr1 || !ptr2) { pr_err("Allocation failed\n"); kfree(ptr1); kfree(ptr2); return; } *ptr1 = *ptr2; kfree(ptr1); kfree(ptr2); } static noinline void __init kmalloc_oob_memset_2(void) { char *ptr; size_t size = 8; pr_info("out-of-bounds in memset2\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } memset(ptr+7, 0, 2); kfree(ptr); } static noinline void __init kmalloc_oob_memset_4(void) { char *ptr; size_t size = 8; pr_info("out-of-bounds in memset4\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } memset(ptr+5, 0, 4); kfree(ptr); } static noinline void __init kmalloc_oob_memset_8(void) { char *ptr; size_t size = 8; pr_info("out-of-bounds in memset8\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } memset(ptr+1, 0, 8); kfree(ptr); } static noinline void __init kmalloc_oob_memset_16(void) { char *ptr; size_t size = 16; pr_info("out-of-bounds in memset16\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } memset(ptr+1, 0, 16); kfree(ptr); } static noinline void __init kmalloc_oob_in_memset(void) { char *ptr; size_t size = 666; pr_info("out-of-bounds in memset\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } memset(ptr, 0, size+5); kfree(ptr); } static noinline void __init kmalloc_uaf(void) { char *ptr; size_t size = 10; pr_info("use-after-free\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } kfree(ptr); *(ptr + 8) = 'x'; } static noinline void __init kmalloc_uaf_memset(void) { char *ptr; size_t size = 33; pr_info("use-after-free in memset\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } kfree(ptr); memset(ptr, 0, size); } static noinline void __init kmalloc_uaf2(void) { char *ptr1, *ptr2; size_t size = 43; pr_info("use-after-free after another kmalloc\n"); ptr1 = kmalloc(size, GFP_KERNEL); if (!ptr1) { pr_err("Allocation failed\n"); return; } kfree(ptr1); ptr2 = kmalloc(size, GFP_KERNEL); if (!ptr2) { pr_err("Allocation failed\n"); return; } ptr1[40] = 'x'; if (ptr1 == ptr2) pr_err("Could not detect use-after-free: ptr1 == ptr2\n"); kfree(ptr2); } static noinline void __init kmem_cache_oob(void) { char *p; size_t size = 200; struct kmem_cache *cache = kmem_cache_create("test_cache", size, 0, 0, NULL); if (!cache) { pr_err("Cache allocation failed\n"); return; } pr_info("out-of-bounds in kmem_cache_alloc\n"); p = kmem_cache_alloc(cache, GFP_KERNEL); if (!p) { pr_err("Allocation failed\n"); kmem_cache_destroy(cache); return; } *p = p[size]; kmem_cache_free(cache, p); kmem_cache_destroy(cache); } static noinline void __init memcg_accounted_kmem_cache(void) { int i; char *p; size_t size = 200; struct kmem_cache *cache; cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL); if (!cache) { pr_err("Cache allocation failed\n"); return; } pr_info("allocate memcg accounted object\n"); /* * 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 char global_array[10]; static noinline void __init kasan_global_oob(void) { volatile int i = 3; char *p = &global_array[ARRAY_SIZE(global_array) + i]; pr_info("out-of-bounds global variable\n"); *(volatile char *)p; } static noinline void __init kasan_stack_oob(void) { char stack_array[10]; volatile int i = 0; char *p = &stack_array[ARRAY_SIZE(stack_array) + i]; pr_info("out-of-bounds on stack\n"); *(volatile char *)p; } static noinline void __init ksize_unpoisons_memory(void) { char *ptr; size_t size = 123, real_size = size; pr_info("ksize() unpoisons the whole allocated chunk\n"); ptr = kmalloc(size, GFP_KERNEL); if (!ptr) { pr_err("Allocation failed\n"); return; } real_size = ksize(ptr); /* This access doesn't trigger an error. */ ptr[size] = 'x'; /* This one does. */ ptr[real_size] = 'y'; kfree(ptr); } static noinline void __init copy_user_test(void) { char *kmem; char __user *usermem; size_t size = 10; int 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; } 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 noinline void __init use_after_scope_test(void) { volatile char *volatile p; pr_info("use-after-scope on int\n"); { int local = 0; p = (char *)&local; } p[0] = 1; p[3] = 1; pr_info("use-after-scope on array\n"); { char local[1024] = {0}; p = local; } p[0] = 1; p[1023] = 1; } static int __init kmalloc_tests_init(void) { /* * Temporarily enable multi-shot mode. Otherwise, we'd only get a * report for the first case. */ bool multishot = kasan_save_enable_multi_shot(); kmalloc_oob_right(); kmalloc_oob_left(); kmalloc_node_oob_right(); #ifdef CONFIG_SLUB kmalloc_pagealloc_oob_right(); #endif kmalloc_large_oob_right(); kmalloc_oob_krealloc_more(); kmalloc_oob_krealloc_less(); kmalloc_oob_16(); kmalloc_oob_in_memset(); kmalloc_oob_memset_2(); kmalloc_oob_memset_4(); kmalloc_oob_memset_8(); kmalloc_oob_memset_16(); kmalloc_uaf(); kmalloc_uaf_memset(); kmalloc_uaf2(); kmem_cache_oob(); memcg_accounted_kmem_cache(); kasan_stack_oob(); kasan_global_oob(); ksize_unpoisons_memory(); copy_user_test(); use_after_scope_test(); kasan_restore_multi_shot(multishot); return -EAGAIN; } module_init(kmalloc_tests_init); MODULE_LICENSE("GPL");