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 "testing_helpers.h"
18
19#define DEV_CGROUP_PROG "./dev_cgroup.bpf.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	/* Use libbpf 1.0 API mode */
31	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
32
33	if (bpf_prog_test_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	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
40	if (cgroup_fd < 0) {
41		printf("Failed to create test cgroup\n");
42		goto out;
43	}
44
45	/* Attach bpf program */
46	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
47		printf("Failed to attach DEV_CGROUP program");
48		goto err;
49	}
50
51	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
52			   &prog_cnt)) {
53		printf("Failed to query attached programs");
54		goto err;
55	}
56
57	/* All operations with /dev/zero and and /dev/urandom are allowed,
58	 * everything else is forbidden.
59	 */
60	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
61	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
62	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
63
64	/* /dev/zero is whitelisted */
65	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
66	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
67	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
68
69	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
70
71	/* src is allowed, target is forbidden */
72	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
73
74	/* src is forbidden, target is allowed */
75	assert(system("dd if=/dev/random of=/dev/zero count=64"));
76
77	error = 0;
78	printf("test_dev_cgroup:PASS\n");
79
80err:
81	cleanup_cgroup_environment();
82
83out:
84	return error;
85}
86