kernel/sysctl-test.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * KUnit test of proc sysctl.
  */

 #include <kunit/test.h>
 #include <linux/sysctl.h>

 #define KUNIT_PROC_READ 0
 #define KUNIT_PROC_WRITE 1

 static int i_zero;
 static int i_one_hundred = 100;

 /*
  * Test that proc_dointvec will not try to use a NULL .data field even when the
  * length is non-zero.
  */
 static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
 {
 	struct ctl_table null_data_table = {
 		.procname = "foo",
 		/*
 		 * Here we are testing that proc_dointvec behaves correctly when
 		 * we give it a NULL .data field. Normally this would point to a
 		 * piece of memory where the value would be stored.
 		 */
 		.data		= NULL,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	/*
 	 * proc_dointvec expects a buffer in user space, so we allocate one. We
 	 * also need to cast it to __user so sparse doesn't get mad.
 	 */
 	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
 							   GFP_USER);
 	size_t len;
 	loff_t pos;

 	/*
 	 * We don't care what the starting length is since proc_dointvec should
 	 * not try to read because .data is NULL.
 	 */
 	len = 1234;
 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
 					       KUNIT_PROC_READ, buffer, &len,
 					       &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);

 	/*
 	 * See above.
 	 */
 	len = 1234;
 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
 					       KUNIT_PROC_WRITE, buffer, &len,
 					       &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);
 }

 /*
  * Similar to the previous test, we create a struct ctrl_table that has a .data
  * field that proc_dointvec cannot do anything with; however, this time it is
  * because we tell proc_dointvec that the size is 0.
  */
 static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
 {
 	int data = 0;
 	struct ctl_table data_maxlen_unset_table = {
 		.procname = "foo",
 		.data		= &data,
 		/*
 		 * So .data is no longer NULL, but we tell proc_dointvec its
 		 * length is 0, so it still shouldn't try to use it.
 		 */
 		.maxlen		= 0,
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
 							   GFP_USER);
 	size_t len;
 	loff_t pos;

 	/*
 	 * As before, we don't care what buffer length is because proc_dointvec
 	 * cannot do anything because its internal .data buffer has zero length.
 	 */
 	len = 1234;
 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
 					       KUNIT_PROC_READ, buffer, &len,
 					       &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);

 	/*
 	 * See previous comment.
 	 */
 	len = 1234;
 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
 					       KUNIT_PROC_WRITE, buffer, &len,
 					       &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);
 }

 /*
  * Here we provide a valid struct ctl_table, but we try to read and write from
  * it using a buffer of zero length, so it should still fail in a similar way as
  * before.
  */
 static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
 {
 	int data = 0;
 	/* Good table. */
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
 							   GFP_USER);
 	/*
 	 * However, now our read/write buffer has zero length.
 	 */
 	size_t len = 0;
 	loff_t pos;

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
 					       &len, &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
 					       &len, &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);
 }

 /*
  * Test that proc_dointvec refuses to read when the file position is non-zero.
  */
 static void sysctl_test_api_dointvec_table_read_but_position_set(
 		struct kunit *test)
 {
 	int data = 0;
 	/* Good table. */
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
 							   GFP_USER);
 	/*
 	 * We don't care about our buffer length because we start off with a
 	 * non-zero file position.
 	 */
 	size_t len = 1234;
 	/*
 	 * proc_dointvec should refuse to read into the buffer since the file
 	 * pos is non-zero.
 	 */
 	loff_t pos = 1;

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
 					       &len, &pos));
 	KUNIT_EXPECT_EQ(test, (size_t)0, len);
 }

 /*
  * Test that we can read a two digit number in a sufficiently size buffer.
  * Nothing fancy.
  */
 static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
 {
 	int data = 0;
 	/* Good table. */
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	size_t len = 4;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;
 	/* Store 13 in the data field. */
 	*((int *)table.data) = 13;

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
 					       user_buffer, &len, &pos));
 	KUNIT_ASSERT_EQ(test, (size_t)3, len);
 	buffer[len] = '\0';
 	/* And we read 13 back out. */
 	KUNIT_EXPECT_STREQ(test, "13\n", buffer);
 }

 /*
  * Same as previous test, just now with negative numbers.
  */
 static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
 {
 	int data = 0;
 	/* Good table. */
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	size_t len = 5;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;
 	*((int *)table.data) = -16;

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
 					       user_buffer, &len, &pos));
 	KUNIT_ASSERT_EQ(test, (size_t)4, len);
 	buffer[len] = '\0';
 	KUNIT_EXPECT_STREQ(test, "-16\n", (char *)buffer);
 }

 /*
  * Test that a simple positive write works.
  */
 static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
 {
 	int data = 0;
 	/* Good table. */
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	char input[] = "9";
 	size_t len = sizeof(input) - 1;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;

 	memcpy(buffer, input, len);

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
 					       user_buffer, &len, &pos));
 	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
 	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
 	KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
 }

 /*
  * Same as previous test, but now with negative numbers.
  */
 static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
 {
 	int data = 0;
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	char input[] = "-9";
 	size_t len = sizeof(input) - 1;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;

 	memcpy(buffer, input, len);

 	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
 					       user_buffer, &len, &pos));
 	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
 	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
 	KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
 }

 /*
  * Test that writing a value smaller than the minimum possible value is not
  * allowed.
  */
 static void sysctl_test_api_dointvec_write_single_less_int_min(
 		struct kunit *test)
 {
 	int data = 0;
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	size_t max_len = 32, len = max_len;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;
 	unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
 					     - (INT_MAX + INT_MIN) + 1;

 	/*
 	 * We use this rigmarole to create a string that contains a value one
 	 * less than the minimum accepted value.
 	 */
 	KUNIT_ASSERT_LT(test,
 			(size_t)snprintf(buffer, max_len, "-%lu",
 					 abs_of_less_than_min),
 			max_len);

 	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
 						     user_buffer, &len, &pos));
 	KUNIT_EXPECT_EQ(test, max_len, len);
 	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
 }

 /*
  * Test that writing the maximum possible value works.
  */
 static void sysctl_test_api_dointvec_write_single_greater_int_max(
 		struct kunit *test)
 {
 	int data = 0;
 	struct ctl_table table = {
 		.procname = "foo",
 		.data		= &data,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 		.extra1		= &i_zero,
 		.extra2         = &i_one_hundred,
 	};
 	size_t max_len = 32, len = max_len;
 	loff_t pos = 0;
 	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
 	char __user *user_buffer = (char __user *)buffer;
 	unsigned long greater_than_max = (unsigned long)INT_MAX + 1;

 	KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
 	KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
 					       greater_than_max),
 			max_len);
 	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
 						     user_buffer, &len, &pos));
 	KUNIT_ASSERT_EQ(test, max_len, len);
 	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
 }

 static struct kunit_case sysctl_test_cases[] = {
 	KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
 	KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
 	KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
 	KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
 	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
 	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
 	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
 	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
 	KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
 	KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
 	{}
 };

 static struct kunit_suite sysctl_test_suite = {
 	.name = "sysctl_test",
 	.test_cases = sysctl_test_cases,
 };

 kunit_test_suites(&sysctl_test_suite);

 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* KUnit test of proc sysctl.
	*/

	#include <kunit/test.h>
	#include <linux/sysctl.h>

	#define KUNIT_PROC_READ 0
	#define KUNIT_PROC_WRITE 1

	static int i_zero;
	static int i_one_hundred = 100;

	/*
	* Test that proc_dointvec will not try to use a NULL .data field even when the
	* length is non-zero.
	*/
	static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
	{
	struct ctl_table null_data_table = {
	.procname = "foo",
	/*
	* Here we are testing that proc_dointvec behaves correctly when
	* we give it a NULL .data field. Normally this would point to a
	* piece of memory where the value would be stored.
	*/
	.data = NULL,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	/*
	* proc_dointvec expects a buffer in user space, so we allocate one. We
	* also need to cast it to __user so sparse doesn't get mad.
	*/
	void __user buffer = (void __user )kunit_kzalloc(test, sizeof(int),
	GFP_USER);
	size_t len;
	loff_t pos;

	/*
	* We don't care what the starting length is since proc_dointvec should
	* not try to read because .data is NULL.
	*/
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
	KUNIT_PROC_READ, buffer, &len,
	&pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);

	/*
	* See above.
	*/
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
	KUNIT_PROC_WRITE, buffer, &len,
	&pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);
	}

	/*
	* Similar to the previous test, we create a struct ctrl_table that has a .data
	* field that proc_dointvec cannot do anything with; however, this time it is
	* because we tell proc_dointvec that the size is 0.
	*/
	static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
	{
	int data = 0;
	struct ctl_table data_maxlen_unset_table = {
	.procname = "foo",
	.data = &data,
	/*
	* So .data is no longer NULL, but we tell proc_dointvec its
	* length is 0, so it still shouldn't try to use it.
	*/
	.maxlen = 0,
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	void __user buffer = (void __user )kunit_kzalloc(test, sizeof(int),
	GFP_USER);
	size_t len;
	loff_t pos;

	/*
	* As before, we don't care what buffer length is because proc_dointvec
	* cannot do anything because its internal .data buffer has zero length.
	*/
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
	KUNIT_PROC_READ, buffer, &len,
	&pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);

	/*
	* See previous comment.
	*/
	len = 1234;
	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
	KUNIT_PROC_WRITE, buffer, &len,
	&pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);
	}

	/*
	* Here we provide a valid struct ctl_table, but we try to read and write from
	* it using a buffer of zero length, so it should still fail in a similar way as
	* before.
	*/
	static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
	{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	void __user buffer = (void __user )kunit_kzalloc(test, sizeof(int),
	GFP_USER);
	/*
	* However, now our read/write buffer has zero length.
	*/
	size_t len = 0;
	loff_t pos;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
	&len, &pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
	&len, &pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);
	}

	/*
	* Test that proc_dointvec refuses to read when the file position is non-zero.
	*/
	static void sysctl_test_api_dointvec_table_read_but_position_set(
	struct kunit *test)
	{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	void __user buffer = (void __user )kunit_kzalloc(test, sizeof(int),
	GFP_USER);
	/*
	* We don't care about our buffer length because we start off with a
	* non-zero file position.
	*/
	size_t len = 1234;
	/*
	* proc_dointvec should refuse to read into the buffer since the file
	* pos is non-zero.
	*/
	loff_t pos = 1;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
	&len, &pos));
	KUNIT_EXPECT_EQ(test, (size_t)0, len);
	}

	/*
	* Test that we can read a two digit number in a sufficiently size buffer.
	* Nothing fancy.
	*/
	static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
	{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	size_t len = 4;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user user_buffer = (char __user )buffer;
	/* Store 13 in the data field. */
	((int )table.data) = 13;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
	user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, (size_t)3, len);
	buffer[len] = '\0';
	/* And we read 13 back out. */
	KUNIT_EXPECT_STREQ(test, "13\n", buffer);
	}

	/*
	* Same as previous test, just now with negative numbers.
	*/
	static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
	{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	size_t len = 5;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user user_buffer = (char __user )buffer;
	((int )table.data) = -16;

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
	user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, (size_t)4, len);
	buffer[len] = '\0';
	KUNIT_EXPECT_STREQ(test, "-16\n", (char *)buffer);
	}

	/*
	* Test that a simple positive write works.
	*/
	static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
	{
	int data = 0;
	/* Good table. */
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	char input[] = "9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user user_buffer = (char __user )buffer;

	memcpy(buffer, input, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
	user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
	KUNIT_EXPECT_EQ(test, 9, ((int )table.data));
	}

	/*
	* Same as previous test, but now with negative numbers.
	*/
	static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
	{
	int data = 0;
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	char input[] = "-9";
	size_t len = sizeof(input) - 1;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, len, GFP_USER);
	char __user user_buffer = (char __user )buffer;

	memcpy(buffer, input, len);

	KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
	user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
	KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
	KUNIT_EXPECT_EQ(test, -9, ((int )table.data));
	}

	/*
	* Test that writing a value smaller than the minimum possible value is not
	* allowed.
	*/
	static void sysctl_test_api_dointvec_write_single_less_int_min(
	struct kunit *test)
	{
	int data = 0;
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	size_t max_len = 32, len = max_len;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
	char __user user_buffer = (char __user )buffer;
	unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
	- (INT_MAX + INT_MIN) + 1;

	/*
	* We use this rigmarole to create a string that contains a value one
	* less than the minimum accepted value.
	*/
	KUNIT_ASSERT_LT(test,
	(size_t)snprintf(buffer, max_len, "-%lu",
	abs_of_less_than_min),
	max_len);

	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
	user_buffer, &len, &pos));
	KUNIT_EXPECT_EQ(test, max_len, len);
	KUNIT_EXPECT_EQ(test, 0, ((int )table.data));
	}

	/*
	* Test that writing the maximum possible value works.
	*/
	static void sysctl_test_api_dointvec_write_single_greater_int_max(
	struct kunit *test)
	{
	int data = 0;
	struct ctl_table table = {
	.procname = "foo",
	.data = &data,
	.maxlen = sizeof(int),
	.mode = 0644,
	.proc_handler = proc_dointvec,
	.extra1 = &i_zero,
	.extra2 = &i_one_hundred,
	};
	size_t max_len = 32, len = max_len;
	loff_t pos = 0;
	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
	char __user user_buffer = (char __user )buffer;
	unsigned long greater_than_max = (unsigned long)INT_MAX + 1;

	KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
	KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
	greater_than_max),
	max_len);
	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
	user_buffer, &len, &pos));
	KUNIT_ASSERT_EQ(test, max_len, len);
	KUNIT_EXPECT_EQ(test, 0, ((int )table.data));
	}

	static struct kunit_case sysctl_test_cases[] = {
	KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
	KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
	KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
	KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
	KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
	KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
	KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
	KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
	{}
	};

	static struct kunit_suite sysctl_test_suite = {
	.name = "sysctl_test",
	.test_cases = sysctl_test_cases,
	};

	kunit_test_suites(&sysctl_test_suite);

	MODULE_LICENSE("GPL v2");