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
stack_mprotect(void)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
exec_cmd(int * monitored_pid)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
test_lsm(struct lsm * skel)54 static 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
test_test_lsm(void)98 void 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
114 close_prog:
115 lsm__destroy(skel);
116 }
117