[PATCH v10 7/9] selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets

[Mickaël Salaün]

On Sat, Mar 09, 2024 at 07:53:18AM +0000, Günther Noack wrote:
> Suggested-by: Mickaël Salaün <mic at digikod.net>
> Signed-off-by: Günther Noack <gnoack at google.com>
> ---
>  tools/testing/selftests/landlock/fs_test.c | 53 ++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
> index d991f44875bc..941e6f9702b7 100644
> --- a/tools/testing/selftests/landlock/fs_test.c
> +++ b/tools/testing/selftests/landlock/fs_test.c
> @@ -20,8 +20,10 @@
>  #include <sys/mount.h>
>  #include <sys/prctl.h>
>  #include <sys/sendfile.h>
> +#include <sys/socket.h>
>  #include <sys/stat.h>
>  #include <sys/sysmacros.h>
> +#include <sys/un.h>
>  #include <sys/vfs.h>
>  #include <unistd.h>
>  
> @@ -3976,6 +3978,57 @@ TEST_F_FORK(layout1, named_pipe_ioctl)
>  	ASSERT_EQ(child_pid, waitpid(child_pid, NULL, 0));
>  }
>  
> +/* For named UNIX domain sockets, no IOCTL restrictions apply. */
> +TEST_F_FORK(layout1, named_unix_domain_socket_ioctl)
> +{
> +	const char *const path = file1_s1d1;
> +	int srv_fd, cli_fd, ruleset_fd;
> +	socklen_t size;
> +	struct sockaddr_un srv_un, cli_un;
> +	const struct landlock_ruleset_attr attr = {
> +		.handled_access_fs = LANDLOCK_ACCESS_FS_IOCTL_DEV,
> +	};
> +
> +	/* Sets up a server */
> +	srv_un.sun_family = AF_UNIX;
> +	strncpy(srv_un.sun_path, path, sizeof(srv_un.sun_path));
> +
> +	ASSERT_EQ(0, unlink(path));
> +	ASSERT_LE(0, (srv_fd = socket(AF_UNIX, SOCK_STREAM, 0)));
> +
> +	size = offsetof(struct sockaddr_un, sun_path) + strlen(srv_un.sun_path);
> +	ASSERT_EQ(0, bind(srv_fd, (struct sockaddr *)&srv_un, size));
> +	ASSERT_EQ(0, listen(srv_fd, 10 /* qlen */));
> +
> +	/* 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));
> +
> +	/* Sets up a client connection to it */
> +	cli_un.sun_family = AF_UNIX;
> +	snprintf(cli_un.sun_path, sizeof(cli_un.sun_path), "%s%ld", path,
> +		 (long)getpid());

I don't think it is useful to have a unique sun_path for a named unix
socket, that's the purpose of naming it right?

> +
> +	ASSERT_LE(0, (cli_fd = socket(AF_UNIX, SOCK_STREAM, 0)));
> +
> +	size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path);
> +	ASSERT_EQ(0, bind(cli_fd, (struct sockaddr *)&cli_un, size));
> +
> +	bzero(&cli_un, sizeof(cli_un));
> +	cli_un.sun_family = AF_UNIX;
> +	strncpy(cli_un.sun_path, path, sizeof(cli_un.sun_path));
> +	size = offsetof(struct sockaddr_un, sun_path) + strlen(cli_un.sun_path);
> +
> +	ASSERT_EQ(0, connect(cli_fd, (struct sockaddr *)&cli_un, size));
> +
> +	/* FIONREAD and other IOCTLs should not be forbidden. */
> +	EXPECT_EQ(0, test_fionread_ioctl(cli_fd));
> +
> +	ASSERT_EQ(0, close(cli_fd));
> +}
> +
>  /* clang-format off */
>  FIXTURE(ioctl) {};
>  
> -- 
> 2.44.0.278.ge034bb2e1d-goog
> 
>