[Devel] [PATCH 22/39] lib: add kasan test module
Andrey Ryabinin
aryabinin at odin.com
Mon Aug 24 03:19:12 PDT 2015
From: Andrey Ryabinin <a.ryabinin at samsung.com>
commit 3f15801cdc2379ca4bf507f48bffd788f9e508ae upstream.
This is a test module doing various nasty things like out of bounds
accesses, use after free. It is useful 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 at samsung.com>
Cc: Dmitry Vyukov <dvyukov at google.com>
Cc: Konstantin Serebryany <kcc at google.com>
Cc: Dmitry Chernenkov <dmitryc at google.com>
Signed-off-by: Andrey Konovalov <adech.fo at gmail.com>
Cc: Yuri Gribov <tetra2005 at gmail.com>
Cc: Konstantin Khlebnikov <koct9i at gmail.com>
Cc: Sasha Levin <sasha.levin at oracle.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim at lge.com>
Cc: Dave Hansen <dave.hansen at intel.com>
Cc: Andi Kleen <andi at firstfloor.org>
Cc: Ingo Molnar <mingo at elte.hu>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Christoph Lameter <cl at linux.com>
Cc: Pekka Enberg <penberg at kernel.org>
Cc: David Rientjes <rientjes at google.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Andrey Ryabinin <aryabinin at odin.com>
---
lib/Kconfig.kasan | 8 ++
lib/Makefile | 1 +
lib/test_kasan.c | 277 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 286 insertions(+)
create mode 100644 lib/test_kasan.c
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index a11ac02..4d47d87 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -42,4 +42,12 @@ config KASAN_INLINE
endchoice
+config TEST_KASAN
+ tristate "Module for testing kasan for bug detection"
+ depends on m && KASAN
+ help
+ This is a test module doing various nasty things like
+ out of bounds accesses, use after free. It is useful for testing
+ kernel debugging features like kernel address sanitizer.
+
endif
diff --git a/lib/Makefile b/lib/Makefile
index 5698586..f5a1515 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -31,6 +31,7 @@ obj-y += string_helpers.o
obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
obj-y += kstrtox.o
obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
+obj-$(CONFIG_TEST_KASAN) += test_kasan.o
obj-y += kmapset.o
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
new file mode 100644
index 0000000..098c08e
--- /dev/null
+++ b/lib/test_kasan.c
@@ -0,0 +1,277 @@
+/*
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <a.ryabinin at 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);
+}
+
+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 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();
+ kasan_stack_oob();
+ kasan_global_oob();
+ return -EAGAIN;
+}
+
+module_init(kmalloc_tests_init);
+MODULE_LICENSE("GPL");
--
2.4.6
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