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linux-next/lib/test_kasan.c
Andrey Ryabinin 0c96350a2d lib/test_kasan.c: add tests for several string/memory API functions 
Arch code may have asm implementation of string/memory API functions
instead of using generic one from lib/string.c.  KASAN don't see memory
accesses in asm code, thus can miss many bugs.

E.g.  on ARM64 KASAN don't see bugs in memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len().  Add tests for these functions to be sure that
we notice the problem on other architectures.

Link: http://lkml.kernel.org/r/20180920135631.23833-3-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:25:18 -07:00

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/*
*
* 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);
}
static noinline void __init kmalloc_pagealloc_uaf(void)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
pr_info("kmalloc pagealloc allocation: use-after-free\n");
ptr = kmalloc(size, GFP_KERNEL);
if (!ptr) {
pr_err("Allocation failed\n");
return;
}
kfree(ptr);
ptr[0] = 0;
}
static noinline void __init kmalloc_pagealloc_invalid_free(void)
{
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
pr_info("kmalloc pagealloc allocation: invalid-free\n");
ptr = kmalloc(size, GFP_KERNEL);
if (!ptr) {
pr_err("Allocation failed\n");
return;
}
kfree(ptr + 1);
}
#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;
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 noinline void __init kasan_alloca_oob_left(void)
{
volatile int i = 10;
char alloca_array[i];
char *p = alloca_array - 1;
pr_info("out-of-bounds to left on alloca\n");
*(volatile char *)p;
}
static noinline void __init kasan_alloca_oob_right(void)
{
volatile int i = 10;
char alloca_array[i];
char *p = alloca_array + i;
pr_info("out-of-bounds to right on alloca\n");
*(volatile char *)p;
}
static noinline void __init kmem_cache_double_free(void)
{
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
if (!cache) {
pr_err("Cache allocation failed\n");
return;
}
pr_info("double-free on heap object\n");
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p) {
pr_err("Allocation failed\n");
kmem_cache_destroy(cache);
return;
}
kmem_cache_free(cache, p);
kmem_cache_free(cache, p);
kmem_cache_destroy(cache);
}
static noinline void __init kmem_cache_invalid_free(void)
{
char *p;
size_t size = 200;
struct kmem_cache *cache;
cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
NULL);
if (!cache) {
pr_err("Cache allocation failed\n");
return;
}
pr_info("invalid-free of heap object\n");
p = kmem_cache_alloc(cache, GFP_KERNEL);
if (!p) {
pr_err("Allocation failed\n");
kmem_cache_destroy(cache);
return;
}
/* Trigger invalid free, the object doesn't get freed */
kmem_cache_free(cache, p + 1);
/*
* Properly free the object to prevent the "Objects remaining in
* test_cache on __kmem_cache_shutdown" BUG failure.
*/
kmem_cache_free(cache, p);
kmem_cache_destroy(cache);
}
static noinline void __init kasan_memchr(void)
{
char *ptr;
size_t size = 24;
pr_info("out-of-bounds in memchr\n");
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
if (!ptr)
return;
memchr(ptr, '1', size + 1);
kfree(ptr);
}
static noinline void __init kasan_memcmp(void)
{
char *ptr;
size_t size = 24;
int arr[9];
pr_info("out-of-bounds in memcmp\n");
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
if (!ptr)
return;
memset(arr, 0, sizeof(arr));
memcmp(ptr, arr, size+1);
kfree(ptr);
}
static noinline void __init kasan_strings(void)
{
char *ptr;
size_t size = 24;
pr_info("use-after-free in strchr\n");
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
if (!ptr)
return;
kfree(ptr);
/*
* Try to cause only 1 invalid access (less spam in dmesg).
* For that we need ptr to point to zeroed byte.
* Skip metadata that could be stored in freed object so ptr
* will likely point to zeroed byte.
*/
ptr += 16;
strchr(ptr, '1');
pr_info("use-after-free in strrchr\n");
strrchr(ptr, '1');
pr_info("use-after-free in strcmp\n");
strcmp(ptr, "2");
pr_info("use-after-free in strncmp\n");
strncmp(ptr, "2", 1);
pr_info("use-after-free in strlen\n");
strlen(ptr);
pr_info("use-after-free in strnlen\n");
strnlen(ptr, 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();
kmalloc_pagealloc_uaf();
kmalloc_pagealloc_invalid_free();
#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();
kasan_alloca_oob_left();
kasan_alloca_oob_right();
ksize_unpoisons_memory();
copy_user_test();
use_after_scope_test();
kmem_cache_double_free();
kmem_cache_invalid_free();
kasan_memchr();
kasan_memcmp();
kasan_strings();
kasan_restore_multi_shot(multishot);
return -EAGAIN;
}
module_init(kmalloc_tests_init);
MODULE_LICENSE("GPL");
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