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/* Copyright (c) 2017 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <linux/bpf.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "cgroup_helpers.h"
#define DEV_CGROUP_PROG "./dev_cgroup.o"
#define TEST_CGROUP "test-bpf-based-device-cgroup/"
int main(int argc, char **argv)
{
struct rlimit limit = { RLIM_INFINITY, RLIM_INFINITY };
struct bpf_object *obj;
int error = EXIT_FAILURE;
int prog_fd, cgroup_fd;
__u32 prog_cnt;
if (setrlimit(RLIMIT_MEMLOCK, &limit) < 0)
perror("Unable to lift memlock rlimit");
if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
&obj, &prog_fd)) {
printf("Failed to load DEV_CGROUP program\n");
goto out;
}
if (setup_cgroup_environment()) {
printf("Failed to load DEV_CGROUP program\n");
goto err;
}
/* Create a cgroup, get fd, and join it */
cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
if (!cgroup_fd) {
printf("Failed to create test cgroup\n");
goto err;
}
if (join_cgroup(TEST_CGROUP)) {
printf("Failed to join cgroup\n");
goto err;
}
/* Attach bpf program */
if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
printf("Failed to attach DEV_CGROUP program");
goto err;
}
if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
&prog_cnt)) {
printf("Failed to query attached programs");
goto err;
}
/* All operations with /dev/zero and and /dev/urandom are allowed,
* everything else is forbidden.
*/
assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
/* /dev/zero is whitelisted */
assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
/* src is allowed, target is forbidden */
assert(system("dd if=/dev/urandom of=/dev/full count=64"));
/* src is forbidden, target is allowed */
assert(system("dd if=/dev/random of=/dev/zero count=64"));
error = 0;
printf("test_dev_cgroup:PASS\n");
err:
cleanup_cgroup_environment();
out:
return error;
}
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