From eba39ca4b155c54adf471a69e91799cc1727873f Mon Sep 17 00:00:00 2001 From: Mickaël Salaün Date: Fri, 6 May 2022 18:08:19 +0200 Subject: landlock: Change landlock_restrict_self(2) check ordering MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit According to the Landlock goal to be a security feature available to unprivileges processes, it makes more sense to first check for no_new_privs before checking anything else (i.e. syscall arguments). Merge inval_fd_enforce and unpriv_enforce_without_no_new_privs tests into the new restrict_self_checks_ordering. This is similar to the previous commit checking other syscalls. Link: https://lore.kernel.org/r/20220506160820.524344-10-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün --- tools/testing/selftests/landlock/base_test.c | 47 ++++++++++++++++++++++------ 1 file changed, 37 insertions(+), 10 deletions(-) (limited to 'tools/testing/selftests/landlock') diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c index 18b779471dcb..21fb33581419 100644 --- a/tools/testing/selftests/landlock/base_test.c +++ b/tools/testing/selftests/landlock/base_test.c @@ -168,22 +168,49 @@ TEST(add_rule_checks_ordering) ASSERT_EQ(0, close(ruleset_fd)); } -TEST(inval_fd_enforce) +/* Tests ordering of syscall argument and permission checks. */ +TEST(restrict_self_checks_ordering) { + const struct landlock_ruleset_attr ruleset_attr = { + .handled_access_fs = LANDLOCK_ACCESS_FS_EXECUTE, + }; + struct landlock_path_beneath_attr path_beneath_attr = { + .allowed_access = LANDLOCK_ACCESS_FS_EXECUTE, + .parent_fd = -1, + }; + const int ruleset_fd = + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0); + + ASSERT_LE(0, ruleset_fd); + path_beneath_attr.parent_fd = + open("/tmp", O_PATH | O_NOFOLLOW | O_DIRECTORY | O_CLOEXEC); + ASSERT_LE(0, path_beneath_attr.parent_fd); + ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, + &path_beneath_attr, 0)); + ASSERT_EQ(0, close(path_beneath_attr.parent_fd)); + + /* Checks unprivileged enforcement without no_new_privs. */ + drop_caps(_metadata); + ASSERT_EQ(-1, landlock_restrict_self(-1, -1)); + ASSERT_EQ(EPERM, errno); + ASSERT_EQ(-1, landlock_restrict_self(-1, 0)); + ASSERT_EQ(EPERM, errno); + ASSERT_EQ(-1, landlock_restrict_self(ruleset_fd, 0)); + ASSERT_EQ(EPERM, errno); + ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)); + /* Checks invalid flags. */ + ASSERT_EQ(-1, landlock_restrict_self(-1, -1)); + ASSERT_EQ(EINVAL, errno); + + /* Checks invalid ruleset FD. */ ASSERT_EQ(-1, landlock_restrict_self(-1, 0)); ASSERT_EQ(EBADF, errno); -} - -TEST(unpriv_enforce_without_no_new_privs) -{ - int err; - drop_caps(_metadata); - err = landlock_restrict_self(-1, 0); - ASSERT_EQ(EPERM, errno); - ASSERT_EQ(err, -1); + /* Checks valid call. */ + ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)); + ASSERT_EQ(0, close(ruleset_fd)); } TEST(ruleset_fd_io) -- cgit v1.2.3