1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2017 Facebook 3 */ 4 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <string.h> 8 #include <errno.h> 9 #include <assert.h> 10 #include <sys/time.h> 11 12 #include <linux/bpf.h> 13 #include <bpf/bpf.h> 14 #include <bpf/libbpf.h> 15 16 #include "cgroup_helpers.h" 17 #include "bpf_rlimit.h" 18 19 #define DEV_CGROUP_PROG "./dev_cgroup.o" 20 21 #define TEST_CGROUP "/test-bpf-based-device-cgroup/" 22 23 int main(int argc, char **argv) 24 { 25 struct bpf_object *obj; 26 int error = EXIT_FAILURE; 27 int prog_fd, cgroup_fd; 28 __u32 prog_cnt; 29 30 if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE, 31 &obj, &prog_fd)) { 32 printf("Failed to load DEV_CGROUP program\n"); 33 goto out; 34 } 35 36 cgroup_fd = cgroup_setup_and_join(TEST_CGROUP); 37 if (cgroup_fd < 0) { 38 printf("Failed to create test cgroup\n"); 39 goto out; 40 } 41 42 /* Attach bpf program */ 43 if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) { 44 printf("Failed to attach DEV_CGROUP program"); 45 goto err; 46 } 47 48 if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL, 49 &prog_cnt)) { 50 printf("Failed to query attached programs"); 51 goto err; 52 } 53 54 /* All operations with /dev/zero and and /dev/urandom are allowed, 55 * everything else is forbidden. 56 */ 57 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); 58 assert(system("mknod /tmp/test_dev_cgroup_null c 1 3")); 59 assert(system("rm -f /tmp/test_dev_cgroup_null") == 0); 60 61 /* /dev/zero is whitelisted */ 62 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0); 63 assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0); 64 assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0); 65 66 assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0); 67 68 /* src is allowed, target is forbidden */ 69 assert(system("dd if=/dev/urandom of=/dev/full count=64")); 70 71 /* src is forbidden, target is allowed */ 72 assert(system("dd if=/dev/random of=/dev/zero count=64")); 73 74 error = 0; 75 printf("test_dev_cgroup:PASS\n"); 76 77 err: 78 cleanup_cgroup_environment(); 79 80 out: 81 return error; 82 } 83