2019-01-13 20:22:36

by Olof Johansson

Subject: [PATCH] lib: test_ubsan: VLA no longer used in kernel

Since we now build with -Wvla, any use of VLA throws a warning.
Including this test, so... maybe we should just remove the test?

lib/test_ubsan.c: In function 'test_ubsan_vla_bound_not_positive':
lib/test_ubsan.c:48:2: warning: ISO C90 forbids variable length array 'buf' [-Wvla]

For the out-of-bounds test, switch to non-VLA setup.

lib/test_ubsan.c: In function 'test_ubsan_out_of_bounds':
lib/test_ubsan.c:64:2: warning: ISO C90 forbids variable length array 'arr' [-Wvla]

Cc: Colin Ian King <[email protected]>
Cc: Jinbum Park <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Olof Johansson <[email protected]>

---
lib/test_ubsan.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
index 280f4979d00ed..9ea10adf7a66f 100644
--- a/lib/test_ubsan.c
+++ b/lib/test_ubsan.c
@@ -42,14 +42,6 @@ static void test_ubsan_divrem_overflow(void)
val /= val2;
}

-static void test_ubsan_vla_bound_not_positive(void)
-{
- volatile int size = -1;
- char buf[size];
-
- (void)buf;
-}
-
static void test_ubsan_shift_out_of_bounds(void)
{
volatile int val = -1;
@@ -61,7 +53,7 @@ static void test_ubsan_shift_out_of_bounds(void)
static void test_ubsan_out_of_bounds(void)
{
volatile int i = 4, j = 5;
- volatile int arr[i];
+ volatile int arr[4];

arr[j] = i;
}
@@ -113,7 +105,6 @@ static const test_ubsan_fp test_ubsan_array[] = {
test_ubsan_mul_overflow,
test_ubsan_negate_overflow,
test_ubsan_divrem_overflow,
- test_ubsan_vla_bound_not_positive,
test_ubsan_shift_out_of_bounds,
test_ubsan_out_of_bounds,
test_ubsan_load_invalid_value,
--
2.11.0

2019-01-14 00:17:53

by Kees Cook

Subject: Re: [PATCH] lib: test_ubsan: VLA no longer used in kernel

On Sun, Jan 13, 2019 at 10:32 AM Olof Johansson <[email protected]> wrote:
>
> Since we now build with -Wvla, any use of VLA throws a warning.
> Including this test, so... maybe we should just remove the test?
>
> lib/test_ubsan.c: In function 'test_ubsan_vla_bound_not_positive':
> lib/test_ubsan.c:48:2: warning: ISO C90 forbids variable length array 'buf' [-Wvla]

I patched the Makefile to remove -Wvla for the *SAN tests. Something
recently seems to be stripping it from the build command line, though.
I haven't figured out what's going on...

-Kees

>
> For the out-of-bounds test, switch to non-VLA setup.
>
> lib/test_ubsan.c: In function 'test_ubsan_out_of_bounds':
> lib/test_ubsan.c:64:2: warning: ISO C90 forbids variable length array 'arr' [-Wvla]
>
> Cc: Colin Ian King <[email protected]>
> Cc: Jinbum Park <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Kees Cook <[email protected]>
> Signed-off-by: Olof Johansson <[email protected]>
>
> ---
> lib/test_ubsan.c | 11 +----------
> 1 file changed, 1 insertion(+), 10 deletions(-)
>
> diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
> index 280f4979d00ed..9ea10adf7a66f 100644
> --- a/lib/test_ubsan.c
> +++ b/lib/test_ubsan.c
> @@ -42,14 +42,6 @@ static void test_ubsan_divrem_overflow(void)
> val /= val2;
> }
>
> -static void test_ubsan_vla_bound_not_positive(void)
> -{
> - volatile int size = -1;
> - char buf[size];
> -
> - (void)buf;
> -}
> -
> static void test_ubsan_shift_out_of_bounds(void)
> {
> volatile int val = -1;
> @@ -61,7 +53,7 @@ static void test_ubsan_shift_out_of_bounds(void)
> static void test_ubsan_out_of_bounds(void)
> {
> volatile int i = 4, j = 5;
> - volatile int arr[i];
> + volatile int arr[4];
>
> arr[j] = i;
> }
> @@ -113,7 +105,6 @@ static const test_ubsan_fp test_ubsan_array[] = {
> test_ubsan_mul_overflow,
> test_ubsan_negate_overflow,
> test_ubsan_divrem_overflow,
> - test_ubsan_vla_bound_not_positive,
> test_ubsan_shift_out_of_bounds,
> test_ubsan_out_of_bounds,
> test_ubsan_load_invalid_value,
> --
> 2.11.0
>


--
Kees Cook

2019-01-14 06:49:09

by Dmitry Vyukov

Subject: Re: [PATCH] lib: test_ubsan: VLA no longer used in kernel

On Sun, Jan 13, 2019 at 7:32 PM Olof Johansson <[email protected]> wrote:
>
> Since we now build with -Wvla, any use of VLA throws a warning.
> Including this test, so... maybe we should just remove the test?
>
> lib/test_ubsan.c: In function 'test_ubsan_vla_bound_not_positive':
> lib/test_ubsan.c:48:2: warning: ISO C90 forbids variable length array 'buf' [-Wvla]
>
> For the out-of-bounds test, switch to non-VLA setup.
>
> lib/test_ubsan.c: In function 'test_ubsan_out_of_bounds':
> lib/test_ubsan.c:64:2: warning: ISO C90 forbids variable length array 'arr' [-Wvla]
>
> Cc: Colin Ian King <[email protected]>
> Cc: Jinbum Park <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Kees Cook <[email protected]>
> Signed-off-by: Olof Johansson <[email protected]>

Acked-by: Dmitry Vyukov <[email protected]>

> ---
> lib/test_ubsan.c | 11 +----------
> 1 file changed, 1 insertion(+), 10 deletions(-)
>
> diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
> index 280f4979d00ed..9ea10adf7a66f 100644
> --- a/lib/test_ubsan.c
> +++ b/lib/test_ubsan.c
> @@ -42,14 +42,6 @@ static void test_ubsan_divrem_overflow(void)
> val /= val2;
> }
>
> -static void test_ubsan_vla_bound_not_positive(void)
> -{
> - volatile int size = -1;
> - char buf[size];
> -
> - (void)buf;
> -}
> -
> static void test_ubsan_shift_out_of_bounds(void)
> {
> volatile int val = -1;
> @@ -61,7 +53,7 @@ static void test_ubsan_shift_out_of_bounds(void)
> static void test_ubsan_out_of_bounds(void)
> {
> volatile int i = 4, j = 5;
> - volatile int arr[i];
> + volatile int arr[4];
>
> arr[j] = i;
> }
> @@ -113,7 +105,6 @@ static const test_ubsan_fp test_ubsan_array[] = {
> test_ubsan_mul_overflow,
> test_ubsan_negate_overflow,
> test_ubsan_divrem_overflow,
> - test_ubsan_vla_bound_not_positive,
> test_ubsan_shift_out_of_bounds,
> test_ubsan_out_of_bounds,
> test_ubsan_load_invalid_value,
> --
> 2.11.0
>