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