selftests/landlock: Add tests for FS topology changes with network rules

Add 2 tests to the layout1 fixture:
* topology_changes_with_net_only: Checks that FS topology
  changes are not denied by network-only restrictions.
* topology_changes_with_net_and_fs: Make sure that FS topology
  changes are still denied with FS and network restrictions.

This specifically test commit d7220364039f ("landlock: Allow FS topology
changes for domains without such rule type").

Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Link: https://lore.kernel.org/r/20231027154615.815134-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 68b7a89cf65b82cb2a8325f59b682d3a79b0f0d7..18e1f86a6234ca323be3e82a8c8d0d7b770380e2 100644 (file)
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -1625,6 +1625,65 @@ TEST_F_FORK(layout1, move_mount)
        clear_cap(_metadata, CAP_SYS_ADMIN);
 }
 
+TEST_F_FORK(layout1, topology_changes_with_net_only)
+{
+       const struct landlock_ruleset_attr ruleset_net = {
+               .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
+                                     LANDLOCK_ACCESS_NET_CONNECT_TCP,
+       };
+       int ruleset_fd;
+
+       /* Add network restrictions. */
+       ruleset_fd =
+               landlock_create_ruleset(&ruleset_net, sizeof(ruleset_net), 0);
+       ASSERT_LE(0, ruleset_fd);
+       enforce_ruleset(_metadata, ruleset_fd);
+       ASSERT_EQ(0, close(ruleset_fd));
+
+       /* Mount, remount, move_mount, umount, and pivot_root checks. */
+       set_cap(_metadata, CAP_SYS_ADMIN);
+       ASSERT_EQ(0, mount_opt(&mnt_tmp, dir_s1d2));
+       ASSERT_EQ(0, mount(NULL, dir_s1d2, NULL, MS_PRIVATE | MS_REC, NULL));
+       ASSERT_EQ(0, syscall(__NR_move_mount, AT_FDCWD, dir_s1d2, AT_FDCWD,
+                            dir_s2d2, 0));
+       ASSERT_EQ(0, umount(dir_s2d2));
+       ASSERT_EQ(0, syscall(__NR_pivot_root, dir_s3d2, dir_s3d3));
+       ASSERT_EQ(0, chdir("/"));
+       clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+TEST_F_FORK(layout1, topology_changes_with_net_and_fs)
+{
+       const struct landlock_ruleset_attr ruleset_net_fs = {
+               .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
+                                     LANDLOCK_ACCESS_NET_CONNECT_TCP,
+               .handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE,
+       };
+       int ruleset_fd;
+
+       /* Add network and filesystem restrictions. */
+       ruleset_fd = landlock_create_ruleset(&ruleset_net_fs,
+                                            sizeof(ruleset_net_fs), 0);
+       ASSERT_LE(0, ruleset_fd);
+       enforce_ruleset(_metadata, ruleset_fd);
+       ASSERT_EQ(0, close(ruleset_fd));
+
+       /* Mount, remount, move_mount, umount, and pivot_root checks. */
+       set_cap(_metadata, CAP_SYS_ADMIN);
+       ASSERT_EQ(-1, mount_opt(&mnt_tmp, dir_s1d2));
+       ASSERT_EQ(EPERM, errno);
+       ASSERT_EQ(-1, mount(NULL, dir_s3d2, NULL, MS_PRIVATE | MS_REC, NULL));
+       ASSERT_EQ(EPERM, errno);
+       ASSERT_EQ(-1, syscall(__NR_move_mount, AT_FDCWD, dir_s3d2, AT_FDCWD,
+                             dir_s2d2, 0));
+       ASSERT_EQ(EPERM, errno);
+       ASSERT_EQ(-1, umount(dir_s3d2));
+       ASSERT_EQ(EPERM, errno);
+       ASSERT_EQ(-1, syscall(__NR_pivot_root, dir_s3d2, dir_s3d3));
+       ASSERT_EQ(EPERM, errno);
+       clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
 TEST_F_FORK(layout1, release_inodes)
 {
        const struct rule rules[] = {