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SubjectRe: [PATCH v3 12/13] lib: add kasan test module
Looks good to me.

On Wed, Sep 24, 2014 at 5:44 AM, Andrey Ryabinin <a.ryabinin@samsung.com> wrote:
> This is a test module doing varios nasty things like
> out of bounds accesses, use after free. It is usefull for testing
> kernel debugging features like kernel address sanitizer.
>
> It mostly concentrates on testing of slab allocator, but we
> might want to add more different stuff here in future (like
> stack/global variables out of bounds accesses and so on).
>
> Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
> ---
> lib/Kconfig.kasan | 8 ++
> lib/Makefile | 1 +
> lib/test_kasan.c | 254 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 263 insertions(+)
> create mode 100644 lib/test_kasan.c
>
> diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> index d16b899..faddb0e 100644
> --- a/lib/Kconfig.kasan
> +++ b/lib/Kconfig.kasan
> @@ -19,4 +19,12 @@ config KASAN_SHADOW_OFFSET
> hex
> default 0xdfffe90000000000 if X86_64
>
> +config TEST_KASAN
> + tristate "Module for testing kasan for bug detection"
> + depends on m
> + help
> + This is a test module doing varios nasty things like
> + out of bounds accesses, use after free. It is usefull for testing
> + kernel debugging features like kernel address sanitizer.
> +
> endif
> diff --git a/lib/Makefile b/lib/Makefile
> index 84a56f7..d620d27 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_TEST_MODULE) += test_module.o
> obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
> obj-$(CONFIG_TEST_BPF) += test_bpf.o
> obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
> +obj-$(CONFIG_TEST_KASAN) += test_kasan.o
>
> ifeq ($(CONFIG_DEBUG_KOBJECT),y)
> CFLAGS_kobject.o += -DDEBUG
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> new file mode 100644
> index 0000000..66a04eb
> --- /dev/null
> +++ b/lib/test_kasan.c
> @@ -0,0 +1,254 @@
> +/*
> + *
> + * 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/kernel.h>
> +#include <linux/printk.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/module.h>
> +
> +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);
> +}
> +
> +static noinline void __init kmalloc_large_oob_rigth(void)
> +{
> + char *ptr;
> + size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
> +
> + 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[size1] = '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_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';
> + 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);
> +}
> +
> +int __init kmalloc_tests_init(void)
> +{
> + kmalloc_oob_right();
> + kmalloc_oob_left();
> + kmalloc_node_oob_right();
> + kmalloc_large_oob_rigth();
> + kmalloc_oob_krealloc_more();
> + kmalloc_oob_krealloc_less();
> + kmalloc_oob_16();
> + kmalloc_oob_in_memset();
> + kmalloc_uaf();
> + kmalloc_uaf_memset();
> + kmalloc_uaf2();
> + kmem_cache_oob();
> + return -EAGAIN;
> +}
> +
> +module_init(kmalloc_tests_init);
> +MODULE_LICENSE("GPL");
> --
> 2.1.1
>


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