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-rw-r--r--lib/Kconfig.debug2
-rw-r--r--lib/Kconfig.kasan57
-rw-r--r--lib/Makefile7
-rw-r--r--lib/test_kasan.c346
4 files changed, 409 insertions, 3 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4e35a5d767ed..f9f6be126767 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -635,6 +635,8 @@ config DEBUG_STACKOVERFLOW
source "lib/Kconfig.kmemcheck"
+source "lib/Kconfig.kasan"
+
endmenu # "Memory Debugging"
config DEBUG_SHIRQ
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
new file mode 100644
index 000000000000..53362c1e95a4
--- /dev/null
+++ b/lib/Kconfig.kasan
@@ -0,0 +1,57 @@
+config HAVE_ARCH_KASAN
+ bool
+
+if HAVE_ARCH_KASAN
+
+config KASAN
+ bool "KASan: runtime memory debugger"
+ depends on SLUB_DEBUG
+ select CONSTRUCTORS
+ help
+ Enables kernel address sanitizer - runtime memory debugger,
+ designed to find out-of-bounds accesses and use-after-free bugs.
+ This is strictly a debugging feature and it requires a gcc version
+ of 4.9.2 or later. Detection of out of bounds accesses to stack or
+ global variables requires gcc 5.0 or later.
+ This feature consumes about 1/8 of available memory and brings about
+ ~x3 performance slowdown.
+ For better error detection enable CONFIG_STACKTRACE.
+
+config KASAN_SHADOW_OFFSET
+ hex
+ default 0xdffffc0000000000 if X86_64
+
+choice
+ prompt "Instrumentation type"
+ depends on KASAN
+ default KASAN_OUTLINE
+
+config KASAN_OUTLINE
+ bool "Outline instrumentation"
+ help
+ Before every memory access compiler insert function call
+ __asan_load*/__asan_store*. These functions performs check
+ of shadow memory. This is slower than inline instrumentation,
+ however it doesn't bloat size of kernel's .text section so
+ much as inline does.
+
+config KASAN_INLINE
+ bool "Inline instrumentation"
+ help
+ Compiler directly inserts code checking shadow memory before
+ memory accesses. This is faster than outline (in some workloads
+ it gives about x2 boost over outline instrumentation), but
+ make kernel's .text size much bigger.
+ This requires a gcc version of 5.0 or later.
+
+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 0211d2bd5e17..de5c0b494761 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -30,11 +30,12 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
obj-y += string_helpers.o
obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
obj-y += kstrtox.o
+obj-$(CONFIG_TEST_BPF) += test_bpf.o
+obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
+obj-$(CONFIG_TEST_KASAN) += test_kasan.o
obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
obj-$(CONFIG_TEST_LKM) += test_module.o
obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
-obj-$(CONFIG_TEST_BPF) += test_bpf.o
-obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
ifeq ($(CONFIG_DEBUG_KOBJECT),y)
CFLAGS_kobject.o += -DDEBUG
@@ -142,7 +143,7 @@ obj-$(CONFIG_GLOB) += glob.o
obj-$(CONFIG_MPILIB) += mpi/
obj-$(CONFIG_SIGNATURE) += digsig.o
-obj-$(CONFIG_CLZ_TAB) += clz_tab.o
+lib-$(CONFIG_CLZ_TAB) += clz_tab.o
obj-$(CONFIG_DDR) += jedec_ddr_data.o
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
new file mode 100644
index 000000000000..dc340b321624
--- /dev/null
+++ b/lib/test_kasan.c
@@ -0,0 +1,346 @@
+/*
+ *
+ * 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_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';
+ 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_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();
+ kasan_stack_oob();
+ kasan_global_oob();
+ return -EAGAIN;
+}
+
+module_init(kmalloc_tests_init);
+MODULE_LICENSE("GPL");