test: add test-bpf-lsm

iaguis · iaguis · commit 8216741cf9df · 2021-10-06T10:52:15.000+02:00
diff --git a/src/test/meson.build b/src/test/meson.build
@@ -357,6 +357,17 @@ tests += [
          [],
          core_includes],
 
+        [['src/test/test-bpf-lsm.c'],
+         [libcore,
+          libshared],
+         [libmount,
+          threads,
+          librt,
+          libseccomp,
+          libselinux,
+          libblkid],
+         core_includes],
+
         [['src/test/test-watch-pid.c'],
          [libcore,
           libshared],
diff --git a/src/test/test-bpf-lsm.c b/src/test/test-bpf-lsm.c
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bpf-lsm.h"
+#include "load-fragment.h"
+#include "manager.h"
+#include "process-util.h"
+#include "rlimit-util.h"
+#include "rm-rf.h"
+#include "service.h"
+#include "strv.h"
+#include "tests.h"
+#include "unit.h"
+#include "virt.h"
+
+static int test_restrict_filesystems(Manager *m, const char *unit_name, const char *file_path, char **allowed_filesystems) {
+        _cleanup_free_ char *exec_start = NULL;
+        _cleanup_(unit_freep) Unit *u = NULL;
+        ExecContext *ec = NULL;
+        char **allow_filesystem;
+        int cld_code, r;
+
+        assert_se(u = unit_new(m, sizeof(Service)));
+        assert_se(unit_add_name(u, unit_name) == 0);
+        assert_se(ec = unit_get_exec_context(u));
+
+        STRV_FOREACH(allow_filesystem, allowed_filesystems) {
+                r = config_parse_restrict_filesystems(
+                                u->id, "filename", 1, "Service", 1, "RestrictFileSystems", 0,
+                                *allow_filesystem, ec, u);
+                if (r < 0)
+                        return log_unit_error_errno(u, r, "Failed to parse RestrictFileSystems: %m");
+        }
+
+        assert_se(exec_start = strjoin("cat ", file_path));
+        r = config_parse_exec(u->id, "filename", 1, "Service", 1, "ExecStart",
+                        SERVICE_EXEC_START, exec_start, SERVICE(u)->exec_command, u);
+        if (r < 0)
+                return log_error_errno(r, "Failed to parse ExecStart");
+
+        SERVICE(u)->type = SERVICE_ONESHOT;
+        u->load_state = UNIT_LOADED;
+
+        r = unit_start(u);
+        if (r < 0)
+                return log_error_errno(r, "Unit start failed %m");
+
+        while (!IN_SET(SERVICE(u)->state, SERVICE_DEAD, SERVICE_FAILED)) {
+                r = sd_event_run(m->event, UINT64_MAX);
+                if (r < 0)
+                        return log_error_errno(errno, "Event run failed %m");
+        }
+
+        cld_code = SERVICE(u)->exec_command[SERVICE_EXEC_START]->exec_status.code;
+        if (cld_code != CLD_EXITED) {
+                return log_error_errno(-SYNTHETIC_ERRNO(EBUSY), "ExecStart didn't exited, code='%s'", sigchld_code_to_string(cld_code));
+        }
+
+        if (SERVICE(u)->state != SERVICE_DEAD) {
+                return log_error_errno(-SYNTHETIC_ERRNO(EBUSY), "Service is not dead");
+        }
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(rm_rf_physical_and_freep) char *runtime_dir = NULL;
+        _cleanup_(manager_freep) Manager *m = NULL;
+        _cleanup_free_ char *unit_dir = NULL;
+        struct rlimit rl;
+        int r;
+
+        test_setup_logging(LOG_DEBUG);
+
+        if (getuid() != 0)
+                return log_tests_skipped("not running as root");
+
+        assert_se(getrlimit(RLIMIT_MEMLOCK, &rl) >= 0);
+        rl.rlim_cur = rl.rlim_max = MAX(rl.rlim_max, CAN_MEMLOCK_SIZE);
+        (void) setrlimit_closest(RLIMIT_MEMLOCK, &rl);
+
+        if (!can_memlock())
+                return log_tests_skipped("Can't use mlock(), skipping.");
+
+        r = lsm_bpf_supported();
+        if (r <= 0)
+                return log_tests_skipped("LSM BPF hooks are not supported");
+
+        r = enter_cgroup_subroot(NULL);
+        if (r == -ENOMEDIUM)
+                return log_tests_skipped("cgroupfs not available");
+
+        assert_se(get_testdata_dir("units", &unit_dir) >= 0);
+        assert_se(set_unit_path(unit_dir) >= 0);
+        assert_se(runtime_dir = setup_fake_runtime_dir());
+
+        assert_se(manager_new(UNIT_FILE_SYSTEM, MANAGER_TEST_RUN_BASIC, &m) >= 0);
+        assert_se(manager_startup(m, NULL, NULL, NULL) >= 0);
+
+        /* We need to enable access to the filesystem where the binary is so we
+         * add @common-block */
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/tracing/printk_formats", STRV_MAKE("@common-block")) < 0);
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/tracing/printk_formats", STRV_MAKE("tracefs", "@common-block")) >= 0);
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/tracing/printk_formats", STRV_MAKE("tracefs", "@common-block", "~tracefs")) < 0);
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/debug/sleep_time", STRV_MAKE("@common-block")) < 0);
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/debug/sleep_time", STRV_MAKE("debugfs", "@common-block")) >= 0);
+        assert_se(test_restrict_filesystems(m, "restrict_filesystems_test.service", "/sys/kernel/debug/sleep_time", STRV_MAKE("~debugfs")) < 0);
+
+        return 0;
+}
