This is a good way to test this, IMHO. Good find.
The comment at the bottom is really valuable. :)
Out of curiosity: I suspect that a selftest with NFS or another network-backed
filesystem might be too complicated? Have you tried that manually, by any
chance?
On Wed, Sep 04, 2024 at 06:48:17PM +0800, Mikhail Ivanov wrote:
> Add test validating that Landlock provides restriction of user space
> sockets only.
>
> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@xxxxxxxxxxxxxxxxxxx>
> ---
> .../testing/selftests/landlock/socket_test.c | 39 ++++++++++++++++++-
> 1 file changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/landlock/socket_test.c b/tools/testing/selftests/landlock/socket_test.c
> index ff5ace711697..23698b8c2f4d 100644
> --- a/tools/testing/selftests/landlock/socket_test.c
> +++ b/tools/testing/selftests/landlock/socket_test.c
> @@ -7,7 +7,7 @@
>
> #define _GNU_SOURCE
>
> -#include <linux/landlock.h>
> +#include "landlock.h"
> #include <linux/pfkeyv2.h>
> #include <linux/kcm.h>
> #include <linux/can.h>
> @@ -628,4 +628,41 @@ TEST(unsupported_af_and_prot)
> EXPECT_EQ(ESOCKTNOSUPPORT, test_socket(AF_UNIX, SOCK_PACKET, 0));
> }
>
> +TEST(kernel_socket)
> +{
> + const struct landlock_ruleset_attr ruleset_attr = {
> + .handled_access_socket = LANDLOCK_ACCESS_SOCKET_CREATE,
> + };
> + struct landlock_socket_attr smc_socket_create = {
> + .allowed_access = LANDLOCK_ACCESS_SOCKET_CREATE,
> + .family = AF_SMC,
> + .type = SOCK_STREAM,
> + };
> + int ruleset_fd;
> +
> + /*
> + * Checks that SMC socket is created sucessfuly without
Typo nit: "successfully"
^^ ^^
> + * landlock restrictions.
> + */
> + ASSERT_EQ(0, test_socket(AF_SMC, SOCK_STREAM, 0));
> +
> + ruleset_fd =
> + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
> + ASSERT_LE(0, ruleset_fd);
> +
> + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_SOCKET,
> + &smc_socket_create, 0));
> + enforce_ruleset(_metadata, ruleset_fd);
> + ASSERT_EQ(0, close(ruleset_fd));
> +
> + /*
> + * During the creation of an SMC socket, an internal service TCP socket
> + * is also created (Cf. smc_create_clcsk).
> + *
> + * Checks that Landlock does not restrict creation of the kernel space
> + * socket.
> + */
> + EXPECT_EQ(0, test_socket(AF_SMC, SOCK_STREAM, 0));
> +}
> +
> TEST_HARNESS_MAIN
> --
> 2.34.1
>
Reviewed-by: Günther Noack <gnoack@xxxxxxxxxx>
