[PATCH v10 6/9] selftests/landlock: Test IOCTLs on named pipes

[Mickaël Salaün]

It might be interesting to create a layout with one file of each type
and use that for the IOCTL tests.

On Sat, Mar 09, 2024 at 07:53:17AM +0000, Günther Noack wrote:
> Named pipes should behave like pipes created with pipe(2),
> so we don't want to restrict IOCTLs on them.
> 
> Suggested-by: Mickaël Salaün <mic at digikod.net>
> Signed-off-by: Günther Noack <gnoack at google.com>
> ---
>  tools/testing/selftests/landlock/fs_test.c | 61 ++++++++++++++++++----
>  1 file changed, 52 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
> index 5c47231a722e..d991f44875bc 100644
> --- a/tools/testing/selftests/landlock/fs_test.c
> +++ b/tools/testing/selftests/landlock/fs_test.c
> @@ -3924,6 +3924,58 @@ TEST_F_FORK(layout1, o_path_ftruncate_and_ioctl)
>  	ASSERT_EQ(0, close(fd));
>  }
>  
> +static int test_fionread_ioctl(int fd)
> +{
> +	size_t sz = 0;
> +
> +	if (ioctl(fd, FIONREAD, &sz) < 0 && errno == EACCES)
> +		return errno;
> +	return 0;
> +}
> +
> +/*
> + * Named pipes are not governed by the LANDLOCK_ACCESS_FS_IOCTL_DEV right,
> + * because they are not character or block devices.
> + */
> +TEST_F_FORK(layout1, named_pipe_ioctl)
> +{
> +	pid_t child_pid;
> +	int fd, ruleset_fd;
> +	const char *const path = file1_s1d1;
> +	const struct landlock_ruleset_attr attr = {
> +		.handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV,
> +	};
> +
> +	ASSERT_EQ(0, unlink(path));
> +	ASSERT_EQ(0, mkfifo(path, 0600));
> +
> +	/* Enables Landlock. */
> +	ruleset_fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
> +	ASSERT_LE(0, ruleset_fd);
> +	enforce_ruleset(_metadata, ruleset_fd);
> +	ASSERT_EQ(0, close(ruleset_fd));
> +
> +	/* The child process opens the pipe for writing. */
> +	child_pid = fork();
> +	ASSERT_NE(-1, child_pid);
> +	if (child_pid == 0) {

What is the purpose of this child's code?

> +		fd = open(path, O_WRONLY);
> +		close(fd);
> +		exit(0);
> +	}
> +
> +	fd = open(path, O_RDONLY);
> +	ASSERT_LE(0, fd);
> +
> +	/* FIONREAD is implemented by pipefifo_fops. */
> +	EXPECT_EQ(0, test_fionread_ioctl(fd));
> +
> +	ASSERT_EQ(0, close(fd));
> +	ASSERT_EQ(0, unlink(path));
> +
> +	ASSERT_EQ(child_pid, waitpid(child_pid, NULL, 0));
> +}
> +
>  /* clang-format off */
>  FIXTURE(ioctl) {};
>  
> @@ -3997,15 +4049,6 @@ static int test_tcgets_ioctl(int fd)
>  	return 0;
>  }
>  
> -static int test_fionread_ioctl(int fd)
> -{
> -	size_t sz = 0;
> -
> -	if (ioctl(fd, FIONREAD, &sz) < 0 && errno == EACCES)
> -		return errno;
> -	return 0;
> -}
> -

You should add test_fionread_ioctl() at the right place from the start.

>  TEST_F_FORK(ioctl, handle_dir_access_file)
>  {
>  	const int flag = 0;
> -- 
> 2.44.0.278.ge034bb2e1d-goog
> 
>