[RESEND PATCH v4 3/5] sysctl: add kunit test code to check the min/max encoding of sysctl table entries

[Wen Yang]

Add kunit test code to check the impact of encoding the min/max values
directly in table entries on functions such as proc_rointvec,
proc_rou8vectminmax, proc_rouintvectminmax, and proc_roulongvectminmax,
including basic parsing testing and min/max overflow testing.

Signed-off-by: Wen Yang <wen.yang@xxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Joel Granados <j.granados@xxxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 kernel/sysctl-test.c | 581 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 581 insertions(+)

diff --git a/kernel/sysctl-test.c b/kernel/sysctl-test.c
index 3ac98bb7fb82..23439ce85f2d 100644
--- a/kernel/sysctl-test.c
+++ b/kernel/sysctl-test.c
@@ -415,6 +415,575 @@ static void sysctl_test_register_sysctl_sz_invalid_extra_value(
 	KUNIT_EXPECT_NOT_NULL(test, register_sysctl("foo", table_qux));
 }
 
+static void sysctl_test_api_dointvec_write_with_minmax(
+		struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MIN | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_dointvec_minmax,
+		.min		= -1,
+		.max		= 100,
+	};
+	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;
+	char input1[] = "10";
+	char input2[] = "-5";
+	char input3[] = "200";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+}
+
+static void sysctl_test_api_dointvec_write_with_min(
+		struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MIN,
+		.proc_handler	= proc_dointvec_minmax,
+		.min		= -1,
+	};
+	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;
+	char input1[] = "10";
+	char input2[] = "-5";
+	char input3[] = "2147483647";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, 2147483647, *((int *)table.data));
+}
+
+static void sysctl_test_api_dointvec_write_with_max(
+		struct kunit *test)
+{
+	int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_dointvec_minmax,
+		.max		= 100,
+	};
+	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;
+	char input1[] = "10";
+	char input2[] = "2147483647";
+	char input3[] = "-2147483648";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 10, *((int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dointvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, -2147483648, *((int *)table.data));
+}
+
+static void sysctl_test_api_douintvec_write_with_minmax(
+		struct kunit *test)
+{
+	unsigned int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MIN | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_douintvec_minmax,
+		.min		= 4,
+		.max		= 200,
+	};
+	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;
+	char input1[] = "100";
+	char input2[] = "3";
+	char input3[] = "1000";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 100, *((unsigned int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 100, *((unsigned int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 100, *((unsigned int *)table.data));
+}
+
+static void sysctl_test_api_douintvec_write_with_min(
+		struct kunit *test)
+{
+	unsigned int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MIN,
+		.proc_handler	= proc_douintvec_minmax,
+		.min		= 4,
+	};
+	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;
+	char input1[] = "100";
+	char input2[] = "3";
+	char input3[] = "4294967295";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 100, *((unsigned int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 100, *((unsigned int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, 4294967295, *((unsigned int *)table.data));
+}
+
+static void sysctl_test_api_douintvec_write_with_max(
+		struct kunit *test)
+{
+	unsigned int data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(int),
+		.mode		= 0644 | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_douintvec_minmax,
+		.max		= 1000,
+	};
+	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;
+	char input1[] = "900";
+	char input2[] = "10000";
+	char input3[] = "0";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 900, *((unsigned int *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 900, *((unsigned int *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_douintvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, 0, *((unsigned int *)table.data));
+}
+
+static void sysctl_test_api_dou8vec_write_with_minmax(
+		struct kunit *test)
+{
+	unsigned char data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned char),
+		.mode		= 0644 | SYSCTL_FLAG_MIN | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_dou8vec_minmax,
+		.min		= 3,
+		.max		= 100,
+	};
+	size_t max_len = 8, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "32";
+	char input2[] = "1";
+	char input3[] = "200";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+}
+
+static void sysctl_test_api_dou8vec_write_with_min(
+		struct kunit *test)
+{
+	unsigned char data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned char),
+		.mode		= 0644 | SYSCTL_FLAG_MIN,
+		.proc_handler	= proc_dou8vec_minmax,
+		.min		= 3,
+	};
+	size_t max_len = 8, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "32";
+	char input2[] = "1";
+	char input3[] = "255";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, 255, *((unsigned char *)table.data));
+}
+
+static void sysctl_test_api_dou8vec_write_with_max(
+		struct kunit *test)
+{
+	unsigned char data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned char),
+		.mode		= 0644 | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_dou8vec_minmax,
+		.max		= 200,
+	};
+	size_t max_len = 8, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "32";
+	char input2[] = "0";
+	char input3[] = "255";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 32, *((unsigned char *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input2) - 1, len);
+	KUNIT_EXPECT_EQ(test, 0, *((unsigned char *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_dou8vec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 0, *((unsigned char *)table.data));
+}
+
+static void sysctl_test_api_doulongvec_write_with_minmax(
+		struct kunit *test)
+{
+	unsigned long data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644 | SYSCTL_FLAG_MIN | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_doulongvec_minmax,
+		.min		= 1000,
+		.max		= 3000,
+	};
+	size_t max_len = 64, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "1024";
+	char input2[] = "100";
+	char input3[] = "4096";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 1024, *((unsigned long *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 1024, *((unsigned long *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+				user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 1024, *((unsigned long *)table.data));
+}
+
+static void sysctl_test_api_doulongvec_write_with_min(
+		struct kunit *test)
+{
+	unsigned long data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644 | SYSCTL_FLAG_MIN,
+		.proc_handler	= proc_doulongvec_minmax,
+		.min		= 1000,
+	};
+	size_t max_len = 64, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "1000";
+	char input2[] = "10";
+	char input3[64] = {0};
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 1000, *((unsigned long *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 1000, *((unsigned long *)table.data));
+
+	// test for input3
+	snprintf(input3, sizeof(input3), "%lu", ULONG_MAX);
+	len = strlen(input3);
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, strlen(input3), len);
+	KUNIT_EXPECT_EQ(test, ULONG_MAX, *((unsigned long *)table.data));
+}
+
+static void sysctl_test_api_doulongvec_write_with_max(
+		struct kunit *test)
+{
+	unsigned long data = 0;
+	struct ctl_table table = {
+		.procname = "foo",
+		.data		= &data,
+		.maxlen		= sizeof(unsigned long),
+		.mode		= 0644 | SYSCTL_FLAG_MAX,
+		.proc_handler	= proc_doulongvec_minmax,
+		.max		= 3000,
+	};
+	size_t max_len = 64, len = max_len;
+	loff_t pos = 0;
+	char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
+	char __user *user_buffer = (char __user *)buffer;
+	char input1[] = "1024";
+	char input2[] = "4096";
+	char input3[] = "0";
+
+	// test for input1
+	len = sizeof(input1) - 1;
+	memcpy(buffer, input1, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input1) - 1, len);
+	KUNIT_EXPECT_EQ(test, 1024, *((unsigned long *)table.data));
+
+	// test for input2
+	len = sizeof(input2) - 1;
+	pos = 0;
+	memcpy(buffer, input2, len);
+	KUNIT_EXPECT_EQ(test, -EINVAL, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, 0, pos);
+	KUNIT_EXPECT_EQ(test, 1024, *((unsigned long *)table.data));
+
+	// test for input3
+	len = sizeof(input3) - 1;
+	pos = 0;
+	memcpy(buffer, input3, len);
+	KUNIT_EXPECT_EQ(test, 0, proc_doulongvec_minmax(&table, KUNIT_PROC_WRITE,
+			user_buffer, &len, &pos));
+	KUNIT_EXPECT_EQ(test, sizeof(input3) - 1, len);
+	KUNIT_EXPECT_EQ(test, 0, *((unsigned long *)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),
@@ -427,6 +996,18 @@ static struct kunit_case sysctl_test_cases[] = {
 	KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
 	KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
 	KUNIT_CASE(sysctl_test_register_sysctl_sz_invalid_extra_value),
+	KUNIT_CASE(sysctl_test_api_dointvec_write_with_minmax),
+	KUNIT_CASE(sysctl_test_api_dointvec_write_with_min),
+	KUNIT_CASE(sysctl_test_api_dointvec_write_with_max),
+	KUNIT_CASE(sysctl_test_api_douintvec_write_with_minmax),
+	KUNIT_CASE(sysctl_test_api_douintvec_write_with_min),
+	KUNIT_CASE(sysctl_test_api_douintvec_write_with_max),
+	KUNIT_CASE(sysctl_test_api_dou8vec_write_with_minmax),
+	KUNIT_CASE(sysctl_test_api_dou8vec_write_with_min),
+	KUNIT_CASE(sysctl_test_api_dou8vec_write_with_max),
+	KUNIT_CASE(sysctl_test_api_doulongvec_write_with_minmax),
+	KUNIT_CASE(sysctl_test_api_doulongvec_write_with_min),
+	KUNIT_CASE(sysctl_test_api_doulongvec_write_with_max),
 	{}
 };
 
-- 
2.25.1