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}
94