Commit 73228c7e authored by Patricia Alfonso's avatar Patricia Alfonso Committed by Linus Torvalds
Browse files

KASAN: port KASAN Tests to KUnit 

Transfer all previous tests for KASAN to KUnit so they can be run more
easily.  Using kunit_tool, developers can run these tests with their other
KUnit tests and see "pass" or "fail" with the appropriate KASAN report
instead of needing to parse each KASAN report to test KASAN
functionalities.  All KASAN reports are still printed to dmesg.

Stack tests do not work properly when KASAN_STACK is enabled so those
tests use a check for "if IS_ENABLED(CONFIG_KASAN_STACK)" so they only run
if stack instrumentation is enabled.  If KASAN_STACK is not enabled, KUnit
will print a statement to let the user know this test was not run with
KASAN_STACK enabled.

copy_user_test and kasan_rcu_uaf cannot be run in KUnit so there is a
separate test file for those tests, which can be run as before as a
module.

[trishalfonso@google.com: v14]
  Link: https://lkml.kernel.org/r/20200915035828.570483-4-davidgow@google.com



Signed-off-by: default avatarPatricia Alfonso <trishalfonso@google.com>
Signed-off-by: default avatarDavid Gow <davidgow@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Tested-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200910070331.3358048-4-davidgow@google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 83c4e7a0

lib/Kconfig.kasan

+17 −5
Original line number Diff line number Diff line
@@ -166,12 +166,24 @@ config KASAN_VMALLOC 
	  for KASAN to detect more sorts of errors (and to support vmapped

	  stacks), but at the cost of higher memory usage.



config TEST_KASAN

	tristate "Module for testing KASAN for bug detection"

	depends on m

config KASAN_KUNIT_TEST

	tristate "KUnit-compatible tests of KASAN bug detection capabilities" if !KUNIT_ALL_TESTS

	depends on KASAN && KUNIT

	default KUNIT_ALL_TESTS

	help

	  This is a test module doing various nasty things like

	  out of bounds accesses, use after free. It is useful for testing

	  This is a KUnit test suite doing various nasty things like

	  out of bounds and use after free accesses. It is useful for testing

	  kernel debugging features like KASAN.



	  For more information on KUnit and unit tests in general, please refer

	  to the KUnit documentation in Documentation/dev-tools/kunit



config TEST_KASAN_MODULE

	tristate "KUnit-incompatible tests of KASAN bug detection capabilities"

	depends on m && KASAN

	help

	  This is a part of the KASAN test suite that is incompatible with

	  KUnit. Currently includes tests that do bad copy_from/to_user

	  accesses.



endif # KASAN

lib/Makefile

+3 −1
Original line number Diff line number Diff line
@@ -65,9 +65,11 @@ CFLAGS_test_bitops.o += -Werror 
obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o

obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o

obj-$(CONFIG_TEST_IDA) += test_ida.o

obj-$(CONFIG_TEST_KASAN) += test_kasan.o

obj-$(CONFIG_KASAN_KUNIT_TEST) += test_kasan.o

CFLAGS_test_kasan.o += -fno-builtin

CFLAGS_test_kasan.o += $(call cc-disable-warning, vla)

obj-$(CONFIG_TEST_KASAN_MODULE) += test_kasan_module.o

CFLAGS_test_kasan_module.o += -fno-builtin

obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o

CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla)

UBSAN_SANITIZE_test_ubsan.o := y

lib/test_kasan.c

+255 −432

File changed.

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lib/test_kasan_module.c

0 → 100644
+111 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 *

 * Copyright (c) 2014 Samsung Electronics Co., Ltd.

 * Author: Andrey Ryabinin <a.ryabinin@samsung.com>

 */



#define pr_fmt(fmt) "kasan test: %s " fmt, __func__



#include <linux/mman.h>

#include <linux/module.h>

#include <linux/printk.h>

#include <linux/slab.h>

#include <linux/uaccess.h>



#include "../mm/kasan/kasan.h"



#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)



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 + OOB_TAG_OFF);



	pr_info("out-of-bounds in copy_to_user()\n");

	unused = copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);



	pr_info("out-of-bounds in __copy_from_user()\n");

	unused = __copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);



	pr_info("out-of-bounds in __copy_to_user()\n");

	unused = __copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);



	pr_info("out-of-bounds in __copy_from_user_inatomic()\n");

	unused = __copy_from_user_inatomic(kmem, usermem, size + 1 + OOB_TAG_OFF);



	pr_info("out-of-bounds in __copy_to_user_inatomic()\n");

	unused = __copy_to_user_inatomic(usermem, kmem, size + 1 + OOB_TAG_OFF);



	pr_info("out-of-bounds in strncpy_from_user()\n");

	unused = strncpy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);



	vm_munmap((unsigned long)usermem, PAGE_SIZE);

	kfree(kmem);

}



static struct kasan_rcu_info {

	int i;

	struct rcu_head rcu;

} *global_rcu_ptr;



static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)

{

	struct kasan_rcu_info *fp = container_of(rp,

						struct kasan_rcu_info, rcu);



	kfree(fp);

	fp->i = 1;

}



static noinline void __init kasan_rcu_uaf(void)

{

	struct kasan_rcu_info *ptr;



	pr_info("use-after-free in kasan_rcu_reclaim\n");

	ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);

	if (!ptr) {

		pr_err("Allocation failed\n");

		return;

	}



	global_rcu_ptr = rcu_dereference_protected(ptr, NULL);

	call_rcu(&global_rcu_ptr->rcu, kasan_rcu_reclaim);

}





static int __init test_kasan_module_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();



	copy_user_test();

	kasan_rcu_uaf();



	kasan_restore_multi_shot(multishot);

	return -EAGAIN;

}



module_init(test_kasan_module_init);

MODULE_LICENSE("GPL");