xref: /linux/tools/testing/selftests/bpf/prog_tests/test_lsm.c (revision 48dea9a700c8728cc31a1dd44588b97578de86ee)
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 
16 char *CMD_ARGS[] = {"true", NULL};
17 
18 #define GET_PAGE_ADDR(ADDR, PAGE_SIZE)					\
19 	(char *)(((unsigned long) (ADDR + PAGE_SIZE)) & ~(PAGE_SIZE-1))
20 
21 int 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 
37 int 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 
54 void test_test_lsm(void)
55 {
56 	struct lsm *skel = NULL;
57 	int err, duration = 0;
58 
59 	skel = lsm__open_and_load();
60 	if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
61 		goto close_prog;
62 
63 	err = lsm__attach(skel);
64 	if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
65 		goto close_prog;
66 
67 	err = exec_cmd(&skel->bss->monitored_pid);
68 	if (CHECK(err < 0, "exec_cmd", "err %d errno %d\n", err, errno))
69 		goto close_prog;
70 
71 	CHECK(skel->bss->bprm_count != 1, "bprm_count", "bprm_count = %d\n",
72 	      skel->bss->bprm_count);
73 
74 	skel->bss->monitored_pid = getpid();
75 
76 	err = stack_mprotect();
77 	if (CHECK(errno != EPERM, "stack_mprotect", "want err=EPERM, got %d\n",
78 		  errno))
79 		goto close_prog;
80 
81 	CHECK(skel->bss->mprotect_count != 1, "mprotect_count",
82 	      "mprotect_count = %d\n", skel->bss->mprotect_count);
83 
84 close_prog:
85 	lsm__destroy(skel);
86 }
87