2 files changed, 51 insertions, 8 deletions

diff --git a/kernel/sysctl-test.c b/kernel/sysctl-test.c
index 6ef887c19c48..4e7dcc9187e2 100644
--- a/kernel/sysctl-test.c
+++ b/kernel/sysctl-test.c
@@ -367,6 +367,54 @@ static void sysctl_test_api_dointvec_write_single_greater_int_max(
 	KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
 }
 
+/*
+ * Test that registering an invalid extra value is not allowed.
+ */
+static void sysctl_test_register_sysctl_sz_invalid_extra_value(
+		struct kunit *test)
+{
+	unsigned char data = 0;
+	struct ctl_table table_foo[] = {
+		{
+			.procname	= "foo",
+			.data		= &data,
+			.maxlen		= sizeof(u8),
+			.mode		= 0644,
+			.proc_handler	= proc_dou8vec_minmax,
+			.extra1		= SYSCTL_FOUR,
+			.extra2		= SYSCTL_ONE_THOUSAND,
+		},
+	};
+
+	struct ctl_table table_bar[] = {
+		{
+			.procname	= "bar",
+			.data		= &data,
+			.maxlen		= sizeof(u8),
+			.mode		= 0644,
+			.proc_handler	= proc_dou8vec_minmax,
+			.extra1		= SYSCTL_NEG_ONE,
+			.extra2		= SYSCTL_ONE_HUNDRED,
+		},
+	};
+
+	struct ctl_table table_qux[] = {
+		{
+			.procname	= "qux",
+			.data		= &data,
+			.maxlen		= sizeof(u8),
+			.mode		= 0644,
+			.proc_handler	= proc_dou8vec_minmax,
+			.extra1		= SYSCTL_ZERO,
+			.extra2		= SYSCTL_TWO_HUNDRED,
+		},
+	};
+
+	KUNIT_EXPECT_NULL(test, register_sysctl("foo", table_foo));
+	KUNIT_EXPECT_NULL(test, register_sysctl("foo", table_bar));
+	KUNIT_EXPECT_NOT_NULL(test, register_sysctl("foo", table_qux));
+}
+
 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),
@@ -378,6 +426,7 @@ static struct kunit_case sysctl_test_cases[] = {
 	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),
+	KUNIT_CASE(sysctl_test_register_sysctl_sz_invalid_extra_value),
 	{}
 };
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index e0b917328cf9..c0a1164eaf59 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -977,16 +977,10 @@ int proc_dou8vec_minmax(struct ctl_table *table, int write,
 	if (table->maxlen != sizeof(u8))
 		return -EINVAL;
 
-	if (table->extra1) {
+	if (table->extra1)
 		min = *(unsigned int *) table->extra1;
-		if (min > 255U)
-			return -EINVAL;
-	}
-	if (table->extra2) {
+	if (table->extra2)
 		max = *(unsigned int *) table->extra2;
-		if (max > 255U)
-			return -EINVAL;
-	}
 
 	tmp = *table;