lib/usercopy_kunit.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Kernel module for testing copy_to/from_user infrastructure.
  *
  * Copyright 2013 Google Inc. All Rights Reserved
  *
  * Authors:
  *      Kees Cook       <keescook@chromium.org>
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/mman.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <kunit/test.h>

 /*
  * Several 32-bit architectures support 64-bit {get,put}_user() calls.
  * As there doesn't appear to be anything that can safely determine
  * their capability at compile-time, we just have to opt-out certain archs.
  */
 #if BITS_PER_LONG == 64 || (!(defined(CONFIG_ARM) && !defined(MMU)) && \
 			    !defined(CONFIG_M68K) &&		\
 			    !defined(CONFIG_MICROBLAZE) &&	\
 			    !defined(CONFIG_NIOS2) &&		\
 			    !defined(CONFIG_PPC32) &&		\
 			    !defined(CONFIG_SUPERH))
 # define TEST_U64
 #endif

 struct usercopy_test_priv {
 	char *kmem;
 	char __user *umem;
 	size_t size;
 };

 static bool is_zeroed(void *from, size_t size)
 {
 	return memchr_inv(from, 0x0, size) == NULL;
 }

 /* Test usage of check_nonzero_user(). */
 static void usercopy_test_check_nonzero_user(struct kunit *test)
 {
 	size_t start, end, i, zero_start, zero_end;
 	struct usercopy_test_priv *priv = test->priv;
 	char __user *umem = priv->umem;
 	char *kmem = priv->kmem;
 	size_t size = priv->size;

 	KUNIT_ASSERT_GE_MSG(test, size, 2 * PAGE_SIZE, "buffer too small");

 	/*
 	 * We want to cross a page boundary to exercise the code more
 	 * effectively. We also don't want to make the size we scan too large,
 	 * otherwise the test can take a long time and cause soft lockups. So
 	 * scan a 1024 byte region across the page boundary.
 	 */
 	size = 1024;
 	start = PAGE_SIZE - (size / 2);

 	kmem += start;
 	umem += start;

 	zero_start = size / 4;
 	zero_end = size - zero_start;

 	/*
 	 * We conduct a series of check_nonzero_user() tests on a block of
 	 * memory with the following byte-pattern (trying every possible
 	 * [start,end] pair):
 	 *
 	 *   [ 00 ff 00 ff ... 00 00 00 00 ... ff 00 ff 00 ]
 	 *
 	 * And we verify that check_nonzero_user() acts identically to
 	 * memchr_inv().
 	 */

 	memset(kmem, 0x0, size);
 	for (i = 1; i < zero_start; i += 2)
 		kmem[i] = 0xff;
 	for (i = zero_end; i < size; i += 2)
 		kmem[i] = 0xff;

 	KUNIT_EXPECT_EQ_MSG(test, copy_to_user(umem, kmem, size), 0,
 		"legitimate copy_to_user failed");

 	for (start = 0; start <= size; start++) {
 		for (end = start; end <= size; end++) {
 			size_t len = end - start;
 			int retval = check_zeroed_user(umem + start, len);
 			int expected = is_zeroed(kmem + start, len);

 			KUNIT_ASSERT_EQ_MSG(test, retval, expected,
 				"check_nonzero_user(=%d) != memchr_inv(=%d) mismatch (start=%zu, end=%zu)",
 				retval, expected, start, end);
 		}
 	}
 }

 /* Test usage of copy_struct_from_user(). */
 static void usercopy_test_copy_struct_from_user(struct kunit *test)
 {
 	char *umem_src = NULL, *expected = NULL;
 	struct usercopy_test_priv *priv = test->priv;
 	char __user *umem = priv->umem;
 	char *kmem = priv->kmem;
 	size_t size = priv->size;
 	size_t ksize, usize;

 	umem_src = kunit_kmalloc(test, size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, umem_src);

 	expected = kunit_kmalloc(test, size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected);

 	/* Fill umem with a fixed byte pattern. */
 	memset(umem_src, 0x3e, size);
 	KUNIT_ASSERT_EQ_MSG(test, copy_to_user(umem, umem_src, size), 0,
 		    "legitimate copy_to_user failed");

 	/* Check basic case -- (usize == ksize). */
 	ksize = size;
 	usize = size;

 	memcpy(expected, umem_src, ksize);

 	memset(kmem, 0x0, size);
 	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
 		    "copy_struct_from_user(usize == ksize) failed");
 	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
 		    "copy_struct_from_user(usize == ksize) gives unexpected copy");

 	/* Old userspace case -- (usize < ksize). */
 	ksize = size;
 	usize = size / 2;

 	memcpy(expected, umem_src, usize);
 	memset(expected + usize, 0x0, ksize - usize);

 	memset(kmem, 0x0, size);
 	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
 		    "copy_struct_from_user(usize < ksize) failed");
 	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
 		    "copy_struct_from_user(usize < ksize) gives unexpected copy");

 	/* New userspace (-E2BIG) case -- (usize > ksize). */
 	ksize = size / 2;
 	usize = size;

 	memset(kmem, 0x0, size);
 	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), -E2BIG,
 		    "copy_struct_from_user(usize > ksize) didn't give E2BIG");

 	/* New userspace (success) case -- (usize > ksize). */
 	ksize = size / 2;
 	usize = size;

 	memcpy(expected, umem_src, ksize);
 	KUNIT_EXPECT_EQ_MSG(test, clear_user(umem + ksize, usize - ksize), 0,
 		    "legitimate clear_user failed");

 	memset(kmem, 0x0, size);
 	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
 		    "copy_struct_from_user(usize > ksize) failed");
 	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
 		    "copy_struct_from_user(usize > ksize) gives unexpected copy");
 }

 /*
  * Legitimate usage: none of these copies should fail.
  */
 static void usercopy_test_valid(struct kunit *test)
 {
 	struct usercopy_test_priv *priv = test->priv;
 	char __user *usermem = priv->umem;
 	char *kmem = priv->kmem;

 	memset(kmem, 0x3a, PAGE_SIZE * 2);
 	KUNIT_EXPECT_EQ_MSG(test, 0, copy_to_user(usermem, kmem, PAGE_SIZE),
 	     "legitimate copy_to_user failed");
 	memset(kmem, 0x0, PAGE_SIZE);
 	KUNIT_EXPECT_EQ_MSG(test, 0, copy_from_user(kmem, usermem, PAGE_SIZE),
 	     "legitimate copy_from_user failed");
 	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, kmem + PAGE_SIZE, PAGE_SIZE,
 	     "legitimate usercopy failed to copy data");

 #define test_legit(size, check)						\
 	do {								\
 		size val_##size = (check);				\
 		KUNIT_EXPECT_EQ_MSG(test, 0,				\
 			put_user(val_##size, (size __user *)usermem),	\
 			"legitimate put_user (" #size ") failed");	\
 		val_##size = 0;						\
 		KUNIT_EXPECT_EQ_MSG(test, 0,				\
 			get_user(val_##size, (size __user *)usermem),	\
 			"legitimate get_user (" #size ") failed");	\
 		KUNIT_EXPECT_EQ_MSG(test, val_##size, check,		\
 			"legitimate get_user (" #size ") failed to do copy"); \
 	} while (0)

 	test_legit(u8,  0x5a);
 	test_legit(u16, 0x5a5b);
 	test_legit(u32, 0x5a5b5c5d);
 #ifdef TEST_U64
 	test_legit(u64, 0x5a5b5c5d6a6b6c6d);
 #endif
 #undef test_legit
 }

 /*
  * Invalid usage: none of these copies should succeed.
  */
 static void usercopy_test_invalid(struct kunit *test)
 {
 	struct usercopy_test_priv *priv = test->priv;
 	char __user *usermem = priv->umem;
 	char *bad_usermem = (char *)usermem;
 	char *kmem = priv->kmem;
 	u64 *kmem_u64 = (u64 *)kmem;

 	if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) ||
 	    !IS_ENABLED(CONFIG_MMU)) {
 		kunit_skip(test, "Testing for kernel/userspace address confusion is only sensible on architectures with a shared address space");
 		return;
 	}

 	/* Prepare kernel memory with check values. */
 	memset(kmem, 0x5a, PAGE_SIZE);
 	memset(kmem + PAGE_SIZE, 0, PAGE_SIZE);

 	/* Reject kernel-to-kernel copies through copy_from_user(). */
 	KUNIT_EXPECT_NE_MSG(test, copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
 						 PAGE_SIZE), 0,
 		    "illegal all-kernel copy_from_user passed");

 	/* Destination half of buffer should have been zeroed. */
 	KUNIT_EXPECT_MEMEQ_MSG(test, kmem + PAGE_SIZE, kmem, PAGE_SIZE,
 		    "zeroing failure for illegal all-kernel copy_from_user");

 #if 0
 	/*
 	 * When running with SMAP/PAN/etc, this will Oops the kernel
 	 * due to the zeroing of userspace memory on failure. This needs
 	 * to be tested in LKDTM instead, since this test module does not
 	 * expect to explode.
 	 */
 	KUNIT_EXPECT_NE_MSG(test, copy_from_user(bad_usermem, (char __user *)kmem,
 						 PAGE_SIZE), 0,
 		    "illegal reversed copy_from_user passed");
 #endif
 	KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
 					       PAGE_SIZE), 0,
 		    "illegal all-kernel copy_to_user passed");

 	KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, bad_usermem,
 					       PAGE_SIZE), 0,
 		    "illegal reversed copy_to_user passed");

 #define test_illegal(size, check)							\
 	do {										\
 		size val_##size = (check);						\
 		/* get_user() */							\
 		KUNIT_EXPECT_NE_MSG(test, get_user(val_##size, (size __user *)kmem), 0,	\
 		    "illegal get_user (" #size ") passed");				\
 		KUNIT_EXPECT_EQ_MSG(test, val_##size, 0,				\
 		    "zeroing failure for illegal get_user (" #size ")");		\
 		/* put_user() */							\
 		*kmem_u64 = 0xF09FA4AFF09FA4AF;						\
 		KUNIT_EXPECT_NE_MSG(test, put_user(val_##size, (size __user *)kmem), 0,	\
 		    "illegal put_user (" #size ") passed");				\
 		KUNIT_EXPECT_EQ_MSG(test, *kmem_u64, 0xF09FA4AFF09FA4AF,		\
 		    "illegal put_user (" #size ") wrote to kernel memory!");		\
 	} while (0)

 	test_illegal(u8,  0x5a);
 	test_illegal(u16, 0x5a5b);
 	test_illegal(u32, 0x5a5b5c5d);
 #ifdef TEST_U64
 	test_illegal(u64, 0x5a5b5c5d6a6b6c6d);
 #endif
 #undef test_illegal
 }

 static int usercopy_test_init(struct kunit *test)
 {
 	struct usercopy_test_priv *priv;
 	unsigned long user_addr;

 	if (!IS_ENABLED(CONFIG_MMU)) {
 		kunit_skip(test, "Userspace allocation testing not available on non-MMU systems");
 		return 0;
 	}

 	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
 	test->priv = priv;
 	priv->size = PAGE_SIZE * 2;

 	priv->kmem = kunit_kmalloc(test, priv->size, GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->kmem);

 	user_addr = kunit_vm_mmap(test, NULL, 0, priv->size,
 			    PROT_READ | PROT_WRITE | PROT_EXEC,
 			    MAP_ANONYMOUS | MAP_PRIVATE, 0);
 	KUNIT_ASSERT_NE_MSG(test, user_addr, 0,
 		"Could not create userspace mm");
 	KUNIT_ASSERT_LT_MSG(test, user_addr, (unsigned long)TASK_SIZE,
 		"Failed to allocate user memory");
 	priv->umem = (char __user *)user_addr;

 	return 0;
 }

 static struct kunit_case usercopy_test_cases[] = {
 	KUNIT_CASE(usercopy_test_valid),
 	KUNIT_CASE(usercopy_test_invalid),
 	KUNIT_CASE(usercopy_test_check_nonzero_user),
 	KUNIT_CASE(usercopy_test_copy_struct_from_user),
 	{}
 };

 static struct kunit_suite usercopy_test_suite = {
 	.name = "usercopy",
 	.init = usercopy_test_init,
 	.test_cases = usercopy_test_cases,
 };

 kunit_test_suites(&usercopy_test_suite);
 MODULE_AUTHOR("Kees Cook <kees@kernel.org>");
 MODULE_DESCRIPTION("Kernel module for testing copy_to/from_user infrastructure");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Kernel module for testing copy_to/from_user infrastructure.
	*
	* Copyright 2013 Google Inc. All Rights Reserved
	*
	* Authors:
	* Kees Cook <keescook@chromium.org>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/mman.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/uaccess.h>
	#include <kunit/test.h>

	/*
	* Several 32-bit architectures support 64-bit {get,put}_user() calls.
	* As there doesn't appear to be anything that can safely determine
	* their capability at compile-time, we just have to opt-out certain archs.
	*/
	#if BITS_PER_LONG == 64 \|\| (!(defined(CONFIG_ARM) && !defined(MMU)) && \
	!defined(CONFIG_M68K) && \
	!defined(CONFIG_MICROBLAZE) && \
	!defined(CONFIG_NIOS2) && \
	!defined(CONFIG_PPC32) && \
	!defined(CONFIG_SUPERH))
	# define TEST_U64
	#endif

	struct usercopy_test_priv {
	char *kmem;
	char __user *umem;
	size_t size;
	};

	static bool is_zeroed(void *from, size_t size)
	{
	return memchr_inv(from, 0x0, size) == NULL;
	}

	/* Test usage of check_nonzero_user(). */
	static void usercopy_test_check_nonzero_user(struct kunit *test)
	{
	size_t start, end, i, zero_start, zero_end;
	struct usercopy_test_priv *priv = test->priv;
	char __user *umem = priv->umem;
	char *kmem = priv->kmem;
	size_t size = priv->size;

	KUNIT_ASSERT_GE_MSG(test, size, 2 * PAGE_SIZE, "buffer too small");

	/*
	* We want to cross a page boundary to exercise the code more
	* effectively. We also don't want to make the size we scan too large,
	* otherwise the test can take a long time and cause soft lockups. So
	* scan a 1024 byte region across the page boundary.
	*/
	size = 1024;
	start = PAGE_SIZE - (size / 2);

	kmem += start;
	umem += start;

	zero_start = size / 4;
	zero_end = size - zero_start;

	/*
	* We conduct a series of check_nonzero_user() tests on a block of
	* memory with the following byte-pattern (trying every possible
	* [start,end] pair):
	*
	* [ 00 ff 00 ff ... 00 00 00 00 ... ff 00 ff 00 ]
	*
	* And we verify that check_nonzero_user() acts identically to
	* memchr_inv().
	*/

	memset(kmem, 0x0, size);
	for (i = 1; i < zero_start; i += 2)
	kmem[i] = 0xff;
	for (i = zero_end; i < size; i += 2)
	kmem[i] = 0xff;

	KUNIT_EXPECT_EQ_MSG(test, copy_to_user(umem, kmem, size), 0,
	"legitimate copy_to_user failed");

	for (start = 0; start <= size; start++) {
	for (end = start; end <= size; end++) {
	size_t len = end - start;
	int retval = check_zeroed_user(umem + start, len);
	int expected = is_zeroed(kmem + start, len);

	KUNIT_ASSERT_EQ_MSG(test, retval, expected,
	"check_nonzero_user(=%d) != memchr_inv(=%d) mismatch (start=%zu, end=%zu)",
	retval, expected, start, end);
	}
	}
	}

	/* Test usage of copy_struct_from_user(). */
	static void usercopy_test_copy_struct_from_user(struct kunit *test)
	{
	char umem_src = NULL, expected = NULL;
	struct usercopy_test_priv *priv = test->priv;
	char __user *umem = priv->umem;
	char *kmem = priv->kmem;
	size_t size = priv->size;
	size_t ksize, usize;

	umem_src = kunit_kmalloc(test, size, GFP_KERNEL);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, umem_src);

	expected = kunit_kmalloc(test, size, GFP_KERNEL);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected);

	/* Fill umem with a fixed byte pattern. */
	memset(umem_src, 0x3e, size);
	KUNIT_ASSERT_EQ_MSG(test, copy_to_user(umem, umem_src, size), 0,
	"legitimate copy_to_user failed");

	/* Check basic case -- (usize == ksize). */
	ksize = size;
	usize = size;

	memcpy(expected, umem_src, ksize);

	memset(kmem, 0x0, size);
	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
	"copy_struct_from_user(usize == ksize) failed");
	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
	"copy_struct_from_user(usize == ksize) gives unexpected copy");

	/* Old userspace case -- (usize < ksize). */
	ksize = size;
	usize = size / 2;

	memcpy(expected, umem_src, usize);
	memset(expected + usize, 0x0, ksize - usize);

	memset(kmem, 0x0, size);
	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
	"copy_struct_from_user(usize < ksize) failed");
	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
	"copy_struct_from_user(usize < ksize) gives unexpected copy");

	/* New userspace (-E2BIG) case -- (usize > ksize). */
	ksize = size / 2;
	usize = size;

	memset(kmem, 0x0, size);
	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), -E2BIG,
	"copy_struct_from_user(usize > ksize) didn't give E2BIG");

	/* New userspace (success) case -- (usize > ksize). */
	ksize = size / 2;
	usize = size;

	memcpy(expected, umem_src, ksize);
	KUNIT_EXPECT_EQ_MSG(test, clear_user(umem + ksize, usize - ksize), 0,
	"legitimate clear_user failed");

	memset(kmem, 0x0, size);
	KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0,
	"copy_struct_from_user(usize > ksize) failed");
	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize,
	"copy_struct_from_user(usize > ksize) gives unexpected copy");
	}

	/*
	* Legitimate usage: none of these copies should fail.
	*/
	static void usercopy_test_valid(struct kunit *test)
	{
	struct usercopy_test_priv *priv = test->priv;
	char __user *usermem = priv->umem;
	char *kmem = priv->kmem;

	memset(kmem, 0x3a, PAGE_SIZE * 2);
	KUNIT_EXPECT_EQ_MSG(test, 0, copy_to_user(usermem, kmem, PAGE_SIZE),
	"legitimate copy_to_user failed");
	memset(kmem, 0x0, PAGE_SIZE);
	KUNIT_EXPECT_EQ_MSG(test, 0, copy_from_user(kmem, usermem, PAGE_SIZE),
	"legitimate copy_from_user failed");
	KUNIT_EXPECT_MEMEQ_MSG(test, kmem, kmem + PAGE_SIZE, PAGE_SIZE,
	"legitimate usercopy failed to copy data");

	#define test_legit(size, check) \
	do { \
	size val_##size = (check); \
	KUNIT_EXPECT_EQ_MSG(test, 0, \
	put_user(val_##size, (size __user *)usermem), \
	"legitimate put_user (" #size ") failed"); \
	val_##size = 0; \
	KUNIT_EXPECT_EQ_MSG(test, 0, \
	get_user(val_##size, (size __user *)usermem), \
	"legitimate get_user (" #size ") failed"); \
	KUNIT_EXPECT_EQ_MSG(test, val_##size, check, \
	"legitimate get_user (" #size ") failed to do copy"); \
	} while (0)

	test_legit(u8, 0x5a);
	test_legit(u16, 0x5a5b);
	test_legit(u32, 0x5a5b5c5d);
	#ifdef TEST_U64
	test_legit(u64, 0x5a5b5c5d6a6b6c6d);
	#endif
	#undef test_legit
	}

	/*
	* Invalid usage: none of these copies should succeed.
	*/
	static void usercopy_test_invalid(struct kunit *test)
	{
	struct usercopy_test_priv *priv = test->priv;
	char __user *usermem = priv->umem;
	char bad_usermem = (char )usermem;
	char *kmem = priv->kmem;
	u64 kmem_u64 = (u64 )kmem;

	if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) \|\|
	!IS_ENABLED(CONFIG_MMU)) {
	kunit_skip(test, "Testing for kernel/userspace address confusion is only sensible on architectures with a shared address space");
	return;
	}

	/* Prepare kernel memory with check values. */
	memset(kmem, 0x5a, PAGE_SIZE);
	memset(kmem + PAGE_SIZE, 0, PAGE_SIZE);

	/* Reject kernel-to-kernel copies through copy_from_user(). */
	KUNIT_EXPECT_NE_MSG(test, copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
	PAGE_SIZE), 0,
	"illegal all-kernel copy_from_user passed");

	/* Destination half of buffer should have been zeroed. */
	KUNIT_EXPECT_MEMEQ_MSG(test, kmem + PAGE_SIZE, kmem, PAGE_SIZE,
	"zeroing failure for illegal all-kernel copy_from_user");

	#if 0
	/*
	* When running with SMAP/PAN/etc, this will Oops the kernel
	* due to the zeroing of userspace memory on failure. This needs
	* to be tested in LKDTM instead, since this test module does not
	* expect to explode.
	*/
	KUNIT_EXPECT_NE_MSG(test, copy_from_user(bad_usermem, (char __user *)kmem,
	PAGE_SIZE), 0,
	"illegal reversed copy_from_user passed");
	#endif
	KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
	PAGE_SIZE), 0,
	"illegal all-kernel copy_to_user passed");

	KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, bad_usermem,
	PAGE_SIZE), 0,
	"illegal reversed copy_to_user passed");

	#define test_illegal(size, check) \
	do { \
	size val_##size = (check); \
	/* get_user() */ \
	KUNIT_EXPECT_NE_MSG(test, get_user(val_##size, (size __user *)kmem), 0, \
	"illegal get_user (" #size ") passed"); \
	KUNIT_EXPECT_EQ_MSG(test, val_##size, 0, \
	"zeroing failure for illegal get_user (" #size ")"); \
	/* put_user() */ \
	*kmem_u64 = 0xF09FA4AFF09FA4AF; \
	KUNIT_EXPECT_NE_MSG(test, put_user(val_##size, (size __user *)kmem), 0, \
	"illegal put_user (" #size ") passed"); \
	KUNIT_EXPECT_EQ_MSG(test, *kmem_u64, 0xF09FA4AFF09FA4AF, \
	"illegal put_user (" #size ") wrote to kernel memory!"); \
	} while (0)

	test_illegal(u8, 0x5a);
	test_illegal(u16, 0x5a5b);
	test_illegal(u32, 0x5a5b5c5d);
	#ifdef TEST_U64
	test_illegal(u64, 0x5a5b5c5d6a6b6c6d);
	#endif
	#undef test_illegal
	}

	static int usercopy_test_init(struct kunit *test)
	{
	struct usercopy_test_priv *priv;
	unsigned long user_addr;

	if (!IS_ENABLED(CONFIG_MMU)) {
	kunit_skip(test, "Userspace allocation testing not available on non-MMU systems");
	return 0;
	}

	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
	test->priv = priv;
	priv->size = PAGE_SIZE * 2;

	priv->kmem = kunit_kmalloc(test, priv->size, GFP_KERNEL);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->kmem);

	user_addr = kunit_vm_mmap(test, NULL, 0, priv->size,
	PROT_READ \| PROT_WRITE \| PROT_EXEC,
	MAP_ANONYMOUS \| MAP_PRIVATE, 0);
	KUNIT_ASSERT_NE_MSG(test, user_addr, 0,
	"Could not create userspace mm");
	KUNIT_ASSERT_LT_MSG(test, user_addr, (unsigned long)TASK_SIZE,
	"Failed to allocate user memory");
	priv->umem = (char __user *)user_addr;

	return 0;
	}

	static struct kunit_case usercopy_test_cases[] = {
	KUNIT_CASE(usercopy_test_valid),
	KUNIT_CASE(usercopy_test_invalid),
	KUNIT_CASE(usercopy_test_check_nonzero_user),
	KUNIT_CASE(usercopy_test_copy_struct_from_user),
	{}
	};

	static struct kunit_suite usercopy_test_suite = {
	.name = "usercopy",
	.init = usercopy_test_init,
	.test_cases = usercopy_test_cases,
	};

	kunit_test_suites(&usercopy_test_suite);
	MODULE_AUTHOR("Kees Cook <kees@kernel.org>");
	MODULE_DESCRIPTION("Kernel module for testing copy_to/from_user infrastructure");
	MODULE_LICENSE("GPL");