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	if (setup_cgroup_environment()) {
37		printf("Failed to load DEV_CGROUP program\n");
38		goto err;
39	}
40
41	/* Create a cgroup, get fd, and join it */
42	cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
43	if (cgroup_fd < 0) {
44		printf("Failed to create test cgroup\n");
45		goto err;
46	}
47
48	if (join_cgroup(TEST_CGROUP)) {
49		printf("Failed to join cgroup\n");
50		goto err;
51	}
52
53	/* Attach bpf program */
54	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
55		printf("Failed to attach DEV_CGROUP program");
56		goto err;
57	}
58
59	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
60			   &prog_cnt)) {
61		printf("Failed to query attached programs");
62		goto err;
63	}
64
65	/* All operations with /dev/zero and and /dev/urandom are allowed,
66	 * everything else is forbidden.
67	 */
68	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
69	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
70	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
71
72	/* /dev/zero is whitelisted */
73	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
74	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
75	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
76
77	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
78
79	/* src is allowed, target is forbidden */
80	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
81
82	/* src is forbidden, target is allowed */
83	assert(system("dd if=/dev/random of=/dev/zero count=64"));
84
85	error = 0;
86	printf("test_dev_cgroup:PASS\n");
87
88err:
89	cleanup_cgroup_environment();
90
91out:
92	return error;
93}