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#include <sys/time.h>
14
15#include <linux/bpf.h>
16#include <bpf/bpf.h>
17#include <bpf/libbpf.h>
18
19#include "cgroup_helpers.h"
20#include "bpf_rlimit.h"
21
22#define DEV_CGROUP_PROG "./dev_cgroup.o"
23
24#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
25
26int main(int argc, char **argv)
27{
28	struct bpf_object *obj;
29	int error = EXIT_FAILURE;
30	int prog_fd, cgroup_fd;
31	__u32 prog_cnt;
32
33	if (bpf_prog_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	if (setup_cgroup_environment()) {
40		printf("Failed to load DEV_CGROUP program\n");
41		goto err;
42	}
43
44	/* Create a cgroup, get fd, and join it */
45	cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
46	if (!cgroup_fd) {
47		printf("Failed to create test cgroup\n");
48		goto err;
49	}
50
51	if (join_cgroup(TEST_CGROUP)) {
52		printf("Failed to join cgroup\n");
53		goto err;
54	}
55
56	/* Attach bpf program */
57	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
58		printf("Failed to attach DEV_CGROUP program");
59		goto err;
60	}
61
62	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
63			   &prog_cnt)) {
64		printf("Failed to query attached programs");
65		goto err;
66	}
67
68	/* All operations with /dev/zero and and /dev/urandom are allowed,
69	 * everything else is forbidden.
70	 */
71	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
72	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
73	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
74
75	/* /dev/zero is whitelisted */
76	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
77	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
78	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
79
80	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
81
82	/* src is allowed, target is forbidden */
83	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
84
85	/* src is forbidden, target is allowed */
86	assert(system("dd if=/dev/random of=/dev/zero count=64"));
87
88	error = 0;
89	printf("test_dev_cgroup:PASS\n");
90
91err:
92	cleanup_cgroup_environment();
93
94out:
95	return error;
96}