Re: [PATCH v2 7/9] test_sysctl: add simple proc_dointvec() case

[Kees Cook]

On Fri, Feb 10, 2017 at 4:36 PM, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote:
> 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.
>
> Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
> ---
>  lib/test_sysctl.c                        | 11 ++++++
>  tools/testing/selftests/sysctl/sysctl.sh | 62 ++++++++++++++++++++++++++++++++
>  2 files changed, 73 insertions(+)
>
> diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
> index 9b9ae1a95ab3..c36a024d7351 100644
> --- a/lib/test_sysctl.c
> +++ b/lib/test_sysctl.c
> @@ -34,11 +34,15 @@ 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)",
>  };
>
> @@ -54,6 +58,13 @@ 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),
> diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
> index 14b9d875db42..45fd2ee5739c 100755
> --- a/tools/testing/selftests/sysctl/sysctl.sh
> +++ b/tools/testing/selftests/sysctl/sysctl.sh
> @@ -24,6 +24,7 @@ TEST_FILE=$(mktemp)
>  # we have tons of space.
>  ALL_TESTS="0001:1:1"
>  ALL_TESTS="$ALL_TESTS 0002:1:1"
> +ALL_TESTS="$ALL_TESTS 0003:1:1"
>
>  test_modprobe()
>  {
> @@ -52,6 +53,9 @@ function allow_user_defaults()
>         if [ -z $MAX_DIGITS ]; then
>                 MAX_DIGITS=$(($PAGE_SIZE/8))
>         fi
> +       if [ -z $INT_MAX ]; then
> +               INT_MAX=$(getconf INT_MAX)
> +       fi
>  }
>
>  test_reqs()
> @@ -92,6 +96,9 @@ reset_vals()
>                 int_0001)
>                         VAL="60"
>                         ;;
> +               int_0002)
> +                       VAL="1"
> +                       ;;
>                 string_0001)
>                         VAL="(none)"
>                         ;;
> @@ -261,6 +268,48 @@ run_limit_digit()
>         test_rc
>  }
>
> +# You are using an int
> +run_limit_digit_int()
> +{
> +       echo -n "Testing INT_MAX works ..."
> +       reset_vals
> +       TEST_STR="$INT_MAX"
> +       echo -n $TEST_STR > $TARGET
> +
> +       if ! verify "${TARGET}"; then
> +               echo "FAIL" >&2
> +               rc=1
> +       else
> +               echo "ok"
> +       fi
> +       test_rc
> +
> +       echo -n "Testing INT_MAX + 1 will fail as expected..."
> +       reset_vals
> +       TEST_STR=$(($INT_MAX+1))

Is the shell always going to do the right thing here? Maybe these test
values should be explicitly hard-coded? I'm on the fence...

-Kees

-- 
Kees Cook
Pixel Security