1// SPDX-License-Identifier: GPL-2.0
  2
  3/*
  4 * Copyright (C) 2020 Google LLC.
  5 */
  6
  7#include <test_progs.h>
  8#include <sys/mman.h>
  9#include <sys/wait.h>
 10#include <unistd.h>
 11#include <malloc.h>
 12#include <stdlib.h>
 13
 14#include "lsm.skel.h"
 15
 16char *CMD_ARGS[] = {"true", NULL};
 17
 18#define GET_PAGE_ADDR(ADDR, PAGE_SIZE)					\
 19	(char *)(((unsigned long) (ADDR + PAGE_SIZE)) & ~(PAGE_SIZE-1))
 20
 21int stack_mprotect(void)
 22{
 23	void *buf;
 24	long sz;
 25	int ret;
 26
 27	sz = sysconf(_SC_PAGESIZE);
 28	if (sz < 0)
 29		return sz;
 30
 31	buf = alloca(sz * 3);
 32	ret = mprotect(GET_PAGE_ADDR(buf, sz), sz,
 33		       PROT_READ | PROT_WRITE | PROT_EXEC);
 34	return ret;
 35}
 36
 37int exec_cmd(int *monitored_pid)
 38{
 39	int child_pid, child_status;
 40
 41	child_pid = fork();
 42	if (child_pid == 0) {
 43		*monitored_pid = getpid();
 44		execvp(CMD_ARGS[0], CMD_ARGS);
 45		return -EINVAL;
 46	} else if (child_pid > 0) {
 47		waitpid(child_pid, &child_status, 0);
 48		return child_status;
 49	}
 50
 51	return -EINVAL;
 52}
 53
 54static int test_lsm(struct lsm *skel)
 55{
 56	struct bpf_link *link;
 57	int buf = 1234;
 58	int err;
 59
 60	err = lsm__attach(skel);
 61	if (!ASSERT_OK(err, "attach"))
 62		return err;
 63
 64	/* Check that already linked program can't be attached again. */
 65	link = bpf_program__attach(skel->progs.test_int_hook);
 66	if (!ASSERT_ERR_PTR(link, "attach_link"))
 67		return -1;
 68
 69	err = exec_cmd(&skel->bss->monitored_pid);
 70	if (!ASSERT_OK(err, "exec_cmd"))
 71		return err;
 72
 73	ASSERT_EQ(skel->bss->bprm_count, 1, "bprm_count");
 74
 75	skel->bss->monitored_pid = getpid();
 76
 77	err = stack_mprotect();
 78	if (!ASSERT_EQ(err, -1, "stack_mprotect") ||
 79	    !ASSERT_EQ(errno, EPERM, "stack_mprotect"))
 80		return err;
 81
 82	ASSERT_EQ(skel->bss->mprotect_count, 1, "mprotect_count");
 83
 84	syscall(__NR_setdomainname, &buf, -2L);
 85	syscall(__NR_setdomainname, 0, -3L);
 86	syscall(__NR_setdomainname, ~0L, -4L);
 87
 88	ASSERT_EQ(skel->bss->copy_test, 3, "copy_test");
 89
 90	lsm__detach(skel);
 91
 92	skel->bss->copy_test = 0;
 93	skel->bss->bprm_count = 0;
 94	skel->bss->mprotect_count = 0;
 95	return 0;
 96}
 97
 98void test_test_lsm(void)
 99{
100	struct lsm *skel = NULL;
101	int err;
102
103	skel = lsm__open_and_load();
104	if (!ASSERT_OK_PTR(skel, "lsm_skel_load"))
105		goto close_prog;
106
107	err = test_lsm(skel);
108	if (!ASSERT_OK(err, "test_lsm_first_attach"))
109		goto close_prog;
110
111	err = test_lsm(skel);
112	ASSERT_OK(err, "test_lsm_second_attach");
113
114close_prog:
115	lsm__destroy(skel);
116}