> > + /* Create with NOEXEC and ALLOW_SEALING */
> > + fd = mfd_assert_new("kern_memfd_noexec",
> > + mfd_def_size,
> > + MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC);
> Don't we need to check fd here?
mfd_assert_new will abort() if fd is not valid, so we don't check fd here.
Jeff
On Thu, Jul 28, 2022 at 11:15 PM Jeff Xu <jeffxu@xxxxxxxxxx> wrote:
>
> From: Daniel Verkamp <dverkamp@xxxxxxxxxxxx>
>
> Tests that ensure MFD_NOEXEC memfds have the appropriate mode bits and
> cannot be chmod-ed into being executable.
>
> Co-developed-by: Jeff Xu <jeffxu@xxxxxxxxxx>
> Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxx>
> Signed-off-by: Daniel Verkamp <dverkamp@xxxxxxxxxxxx>
> ---
> tools/testing/selftests/memfd/memfd_test.c | 34 ++++++++++++++++++++++
> 1 file changed, 34 insertions(+)
>
> diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
> index 1d7e7b36bbdd..4906f778564e 100644
> --- a/tools/testing/selftests/memfd/memfd_test.c
> +++ b/tools/testing/selftests/memfd/memfd_test.c
> @@ -36,6 +36,10 @@
> #define MAX_PATH 256
> #endif
>
> +#ifndef MFD_NOEXEC
> +#define MFD_NOEXEC 0x0008U
> +#endif
> +
> /*
> * Default is not to test hugetlbfs
> */
> @@ -1006,6 +1010,35 @@ static void test_seal_exec(void)
> close(fd);
> }
>
> +/*
> + * Test memfd_create with MFD_NOEXEC flag
> + * Test that MFD_NOEXEC applies F_SEAL_EXEC and prevents change of exec bits
> + */
> +static void test_noexec(void)
> +{
> + int fd;
> +
> + printf("%s NOEXEC\n", memfd_str);
> +
> + /* Create with NOEXEC and ALLOW_SEALING */
> + fd = mfd_assert_new("kern_memfd_noexec",
> + mfd_def_size,
> + MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC);
> + mfd_assert_mode(fd, 0666);
> + mfd_assert_has_seals(fd, F_SEAL_EXEC);
> + mfd_fail_chmod(fd, 0777);
> + close(fd);
> +
> + /* Create with NOEXEC but without ALLOW_SEALING */
> + fd = mfd_assert_new("kern_memfd_noexec",
> + mfd_def_size,
> + MFD_CLOEXEC | MFD_NOEXEC);
> + mfd_assert_mode(fd, 0666);
> + mfd_assert_has_seals(fd, F_SEAL_EXEC | F_SEAL_SEAL);
> + mfd_fail_chmod(fd, 0777);
> + close(fd);
> +}
> +
> /*
> * Test sharing via dup()
> * Test that seals are shared between dupped FDs and they're all equal.
> @@ -1179,6 +1212,7 @@ int main(int argc, char **argv)
>
> test_create();
> test_basic();
> + test_noexec();
>
> test_seal_write();
> test_seal_future_write();
> --
> 2.37.1.455.g008518b4e5-goog
>
