1 // SPDX-License-Identifier: GPL-2.0
2 #define _GNU_SOURCE
3 #include <test_progs.h>
4 #include "test_deny_namespace.skel.h"
5 #include <sched.h>
6 #include "cap_helpers.h"
7 #include <stdio.h>
8
wait_for_pid(pid_t pid)9 static int wait_for_pid(pid_t pid)
10 {
11 int status, ret;
12
13 again:
14 ret = waitpid(pid, &status, 0);
15 if (ret == -1) {
16 if (errno == EINTR)
17 goto again;
18
19 return -1;
20 }
21
22 if (!WIFEXITED(status))
23 return -1;
24
25 return WEXITSTATUS(status);
26 }
27
28 /* negative return value -> some internal error
29 * positive return value -> userns creation failed
30 * 0 -> userns creation succeeded
31 */
create_user_ns(void)32 static int create_user_ns(void)
33 {
34 pid_t pid;
35
36 pid = fork();
37 if (pid < 0)
38 return -1;
39
40 if (pid == 0) {
41 if (unshare(CLONE_NEWUSER))
42 _exit(EXIT_FAILURE);
43 _exit(EXIT_SUCCESS);
44 }
45
46 return wait_for_pid(pid);
47 }
48
test_userns_create_bpf(void)49 static void test_userns_create_bpf(void)
50 {
51 __u32 cap_mask = 1ULL << CAP_SYS_ADMIN;
52 __u64 old_caps = 0;
53
54 cap_enable_effective(cap_mask, &old_caps);
55
56 ASSERT_OK(create_user_ns(), "priv new user ns");
57
58 cap_disable_effective(cap_mask, &old_caps);
59
60 ASSERT_EQ(create_user_ns(), EPERM, "unpriv new user ns");
61
62 if (cap_mask & old_caps)
63 cap_enable_effective(cap_mask, NULL);
64 }
65
test_unpriv_userns_create_no_bpf(void)66 static void test_unpriv_userns_create_no_bpf(void)
67 {
68 __u32 cap_mask = 1ULL << CAP_SYS_ADMIN;
69 __u64 old_caps = 0;
70
71 cap_disable_effective(cap_mask, &old_caps);
72
73 ASSERT_OK(create_user_ns(), "no-bpf unpriv new user ns");
74
75 if (cap_mask & old_caps)
76 cap_enable_effective(cap_mask, NULL);
77 }
78
test_deny_namespace(void)79 void test_deny_namespace(void)
80 {
81 struct test_deny_namespace *skel = NULL;
82 int err;
83
84 if (test__start_subtest("unpriv_userns_create_no_bpf"))
85 test_unpriv_userns_create_no_bpf();
86
87 skel = test_deny_namespace__open_and_load();
88 if (!ASSERT_OK_PTR(skel, "skel load"))
89 goto close_prog;
90
91 err = test_deny_namespace__attach(skel);
92 if (!ASSERT_OK(err, "attach"))
93 goto close_prog;
94
95 if (test__start_subtest("userns_create_bpf"))
96 test_userns_create_bpf();
97
98 test_deny_namespace__detach(skel);
99
100 close_prog:
101 test_deny_namespace__destroy(skel);
102 }
103