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
23int 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	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
37	if (cgroup_fd < 0) {
38		printf("Failed to create test cgroup\n");
39		goto out;
40	}
41
42	/* Attach bpf program */
43	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
44		printf("Failed to attach DEV_CGROUP program");
45		goto err;
46	}
47
48	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
49			   &prog_cnt)) {
50		printf("Failed to query attached programs");
51		goto err;
52	}
53
54	/* All operations with /dev/zero and and /dev/urandom are allowed,
55	 * everything else is forbidden.
56	 */
57	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
58	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
59	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
60
61	/* /dev/zero is whitelisted */
62	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
63	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
64	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
65
66	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
67
68	/* src is allowed, target is forbidden */
69	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
70
71	/* src is forbidden, target is allowed */
72	assert(system("dd if=/dev/random of=/dev/zero count=64"));
73
74	error = 0;
75	printf("test_dev_cgroup:PASS\n");
76
77err:
78	cleanup_cgroup_environment();
79
80out:
81	return error;
82}
83