Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#include <sys/resource.h>
15
16#include <linux/bpf.h>
17#include <bpf/bpf.h>
18#include <bpf/libbpf.h>
19
20#include "cgroup_helpers.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 rlimit limit = { RLIM_INFINITY, RLIM_INFINITY };
29 struct bpf_object *obj;
30 int error = EXIT_FAILURE;
31 int prog_fd, cgroup_fd;
32 __u32 prog_cnt;
33
34 if (setrlimit(RLIMIT_MEMLOCK, &limit) < 0)
35 perror("Unable to lift memlock rlimit");
36
37 if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
38 &obj, &prog_fd)) {
39 printf("Failed to load DEV_CGROUP program\n");
40 goto out;
41 }
42
43 if (setup_cgroup_environment()) {
44 printf("Failed to load DEV_CGROUP program\n");
45 goto err;
46 }
47
48 /* Create a cgroup, get fd, and join it */
49 cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
50 if (!cgroup_fd) {
51 printf("Failed to create test cgroup\n");
52 goto err;
53 }
54
55 if (join_cgroup(TEST_CGROUP)) {
56 printf("Failed to join cgroup\n");
57 goto err;
58 }
59
60 /* Attach bpf program */
61 if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
62 printf("Failed to attach DEV_CGROUP program");
63 goto err;
64 }
65
66 if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
67 &prog_cnt)) {
68 printf("Failed to query attached programs");
69 goto err;
70 }
71
72 /* All operations with /dev/zero and and /dev/urandom are allowed,
73 * everything else is forbidden.
74 */
75 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
76 assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
77 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
78
79 /* /dev/zero is whitelisted */
80 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
81 assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
82 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
83
84 assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
85
86 /* src is allowed, target is forbidden */
87 assert(system("dd if=/dev/urandom of=/dev/full count=64"));
88
89 /* src is forbidden, target is allowed */
90 assert(system("dd if=/dev/random of=/dev/zero count=64"));
91
92 error = 0;
93 printf("test_dev_cgroup:PASS\n");
94
95err:
96 cleanup_cgroup_environment();
97
98out:
99 return error;
100}