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 14 #include <linux/bpf.h> 15 #include <bpf/bpf.h> 16 #include <bpf/libbpf.h> 17 18 #include "cgroup_helpers.h" 19 20 #define DEV_CGROUP_PROG "./dev_cgroup.o" 21 22 #define TEST_CGROUP "test-bpf-based-device-cgroup/" 23 24 int main(int argc, char **argv) 25 { 26 struct bpf_object *obj; 27 int error = EXIT_FAILURE; 28 int prog_fd, cgroup_fd; 29 __u32 prog_cnt; 30 31 if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE, 32 &obj, &prog_fd)) { 33 printf("Failed to load DEV_CGROUP program\n"); 34 goto err; 35 } 36 37 if (setup_cgroup_environment()) { 38 printf("Failed to load DEV_CGROUP program\n"); 39 goto err; 40 } 41 42 /* Create a cgroup, get fd, and join it */ 43 cgroup_fd = create_and_get_cgroup(TEST_CGROUP); 44 if (!cgroup_fd) { 45 printf("Failed to create test cgroup\n"); 46 goto err; 47 } 48 49 if (join_cgroup(TEST_CGROUP)) { 50 printf("Failed to join cgroup\n"); 51 goto err; 52 } 53 54 /* Attach bpf program */ 55 if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) { 56 printf("Failed to attach DEV_CGROUP program"); 57 goto err; 58 } 59 60 if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL, 61 &prog_cnt)) { 62 printf("Failed to query attached programs"); 63 goto err; 64 } 65 66 /* All operations with /dev/zero and and /dev/urandom are allowed, 67 * everything else is forbidden. 68 */ 69 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); 70 assert(system("mknod /tmp/test_dev_cgroup_null c 1 3")); 71 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); 72 73 /* /dev/zero is whitelisted */ 74 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0); 75 assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0); 76 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0); 77 78 assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0); 79 80 /* src is allowed, target is forbidden */ 81 assert(system("dd if=/dev/urandom of=/dev/full count=64")); 82 83 /* src is forbidden, target is allowed */ 84 assert(system("dd if=/dev/random of=/dev/zero count=64")); 85 86 error = 0; 87 printf("test_dev_cgroup:PASS\n"); 88 89 err: 90 cleanup_cgroup_environment(); 91 92 return error; 93 } 94