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 "testing_helpers.h"
18
19 #define DEV_CGROUP_PROG "./dev_cgroup.bpf.o"
20
21 #define TEST_CGROUP "/test-bpf-based-device-cgroup/"
22
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 /* Use libbpf 1.0 API mode */
31 libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
32
33 if (bpf_prog_test_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
34 &obj, &prog_fd)) {
35 printf("Failed to load DEV_CGROUP program\n");
36 goto out;
37 }
38
39 cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
40 if (cgroup_fd < 0) {
41 printf("Failed to create test cgroup\n");
42 goto out;
43 }
44
45 /* Attach bpf program */
46 if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
47 printf("Failed to attach DEV_CGROUP program");
48 goto err;
49 }
50
51 if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
52 &prog_cnt)) {
53 printf("Failed to query attached programs");
54 goto err;
55 }
56
57 /* All operations with /dev/zero and and /dev/urandom are allowed,
58 * everything else is forbidden.
59 */
60 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
61 assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
62 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
63
64 /* /dev/zero is whitelisted */
65 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
66 assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
67 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
68
69 assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
70
71 /* src is allowed, target is forbidden */
72 assert(system("dd if=/dev/urandom of=/dev/full count=64"));
73
74 /* src is forbidden, target is allowed */
75 assert(system("dd if=/dev/random of=/dev/zero count=64"));
76
77 error = 0;
78 printf("test_dev_cgroup:PASS\n");
79
80 err:
81 cleanup_cgroup_environment();
82
83 out:
84 return error;
85 }
86
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