[PATCH v2 4/6] selftests/landlock: Test ioctl with memfds

[Mickaël Salaün]

On 23/06/2023 16:43, Günther Noack wrote:
> Because the ioctl right is associated with the opened file,
> we expect that it will work with files which are opened by means
> other than open(2).
> 
> Signed-off-by: Günther Noack <gnoack at google.com>
> ---
>   tools/testing/selftests/landlock/fs_test.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
> index 0f0899768fe7..ebd93e895775 100644
> --- a/tools/testing/selftests/landlock/fs_test.c
> +++ b/tools/testing/selftests/landlock/fs_test.c
> @@ -3716,18 +3716,20 @@ TEST_F_FORK(ftruncate, open_and_ftruncate_in_different_processes)
>   	ASSERT_EQ(0, close(socket_fds[1]));
>   }
>   
> -TEST(memfd_ftruncate)
> +TEST(memfd_ftruncate_and_ioctl)

You could create memfd fixture/teardown with TEST_F(memfd, ftruncate) 
and TEST_F(memfd, ioctl) to cleanly differentiate these tests.


>   {
> -	int fd;
> +	int fd, n;
>   
>   	fd = memfd_create("name", MFD_CLOEXEC);
>   	ASSERT_LE(0, fd);
>   
>   	/*
> -	 * Checks that ftruncate is permitted on file descriptors that are
> -	 * created in ways other than open(2).
> +	 * Checks that operations associated with the opened file
> +	 * (ftruncate, ioctl) are permitted on file descriptors that
> +	 * are created in ways other than open(2).
>   	 */
>   	EXPECT_EQ(0, test_ftruncate(fd));

I previously missed it but this test should check ftruncate with and 
without FS sandboxing to be sure that the resulting behavior is the 
same. Ditto for the IOCTL test.


> +	EXPECT_EQ(0, ioctl(fd, FIONREAD, &n));
>   
>   	ASSERT_EQ(0, close(fd));

EXPECT_EQ() for close() should be enough right?

>   }