test_sysctl: add simple proc_dointvec() case

Test against a simple proc_dointvec() case.  While at it, add a test
against INT_MAX.  Make sure INT_MAX works, and INT_MAX+1 will fail.
Also test negative values work.

Link: http://lkml.kernel.org/r/20170630224431.17374-5-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index b2163bfb6eb2..1472e1ae4931 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -41,11 +41,15 @@ static int i_one_hundred = 100;
 
 struct test_sysctl_data {
         int int_0001;
+        int int_0002;
+
         char string_0001[65];
 };
 
 static struct test_sysctl_data test_data = {
         .int_0001 = 60,
+        .int_0002 = 1,
+
         .string_0001 = "(none)",
 };
 
@@ -61,6 +65,13 @@ static struct ctl_table test_table[] = {
                 .extra2         = &i_one_hundred,
         },
         {
+                .procname       = "int_0002",
+                .data           = &test_data.int_0002,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        {
                 .procname       = "string_0001",
                 .data           = &test_data.string_0001,
                 .maxlen         = sizeof(test_data.string_0001),