1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2017 Facebook
3 */
4
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <errno.h>
9 #include <assert.h>
10 #include <sys/time.h>
11
12 #include <linux/bpf.h>
13 #include <bpf/bpf.h>
14 #include <bpf/libbpf.h>
15
16 #include "cgroup_helpers.h"
17 #include "bpf_rlimit.h"
18
19 #define DEV_CGROUP_PROG "./dev_cgroup.o"
20
21 #define TEST_CGROUP "/test-bpf-based-device-cgroup/"
22
main(int argc,char ** argv)23 int main(int argc, char **argv)
24 {
25 struct bpf_object *obj;
26 int error = EXIT_FAILURE;
27 int prog_fd, cgroup_fd;
28 __u32 prog_cnt;
29
30 if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
31 &obj, &prog_fd)) {
32 printf("Failed to load DEV_CGROUP program\n");
33 goto out;
34 }
35
36 if (setup_cgroup_environment()) {
37 printf("Failed to load DEV_CGROUP program\n");
38 goto err;
39 }
40
41 /* Create a cgroup, get fd, and join it */
42 cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
43 if (cgroup_fd < 0) {
44 printf("Failed to create test cgroup\n");
45 goto err;
46 }
47
48 if (join_cgroup(TEST_CGROUP)) {
49 printf("Failed to join cgroup\n");
50 goto err;
51 }
52
53 /* Attach bpf program */
54 if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
55 printf("Failed to attach DEV_CGROUP program");
56 goto err;
57 }
58
59 if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
60 &prog_cnt)) {
61 printf("Failed to query attached programs");
62 goto err;
63 }
64
65 /* All operations with /dev/zero and and /dev/urandom are allowed,
66 * everything else is forbidden.
67 */
68 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
69 assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
70 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
71
72 /* /dev/zero is whitelisted */
73 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
74 assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
75 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
76
77 assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
78
79 /* src is allowed, target is forbidden */
80 assert(system("dd if=/dev/urandom of=/dev/full count=64"));
81
82 /* src is forbidden, target is allowed */
83 assert(system("dd if=/dev/random of=/dev/zero count=64"));
84
85 error = 0;
86 printf("test_dev_cgroup:PASS\n");
87
88 err:
89 cleanup_cgroup_environment();
90
91 out:
92 return error;
93 }
94
