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 26 int 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 95 err: 96 cleanup_cgroup_environment(); 97 98 out: 99 return error; 100 } 101