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