173 lines · c
1// SPDX-License-Identifier: GPL-2.02 3/*4 * Copyright (C) 2020 Google LLC.5 */6 7#include <asm-generic/errno-base.h>8#include <sys/stat.h>9#include <test_progs.h>10#include <linux/limits.h>11 12#include "local_storage.skel.h"13#include "network_helpers.h"14#include "task_local_storage_helpers.h"15 16#define TEST_STORAGE_VALUE 0xbeefdead17 18struct storage {19 void *inode;20 unsigned int value;21};22 23/* Fork and exec the provided rm binary and return the exit code of the24 * forked process and its pid.25 */26static int run_self_unlink(struct local_storage *skel, const char *rm_path)27{28 int child_pid, child_status, ret;29 int null_fd;30 31 child_pid = fork();32 if (child_pid == 0) {33 null_fd = open("/dev/null", O_WRONLY);34 dup2(null_fd, STDOUT_FILENO);35 dup2(null_fd, STDERR_FILENO);36 close(null_fd);37 38 skel->bss->monitored_pid = getpid();39 /* Use the copied /usr/bin/rm to delete itself40 * /tmp/copy_of_rm /tmp/copy_of_rm.41 */42 ret = execlp(rm_path, rm_path, rm_path, NULL);43 if (ret)44 exit(errno);45 } else if (child_pid > 0) {46 waitpid(child_pid, &child_status, 0);47 ASSERT_EQ(skel->data->task_storage_result, 0, "task_storage_result");48 return WEXITSTATUS(child_status);49 }50 51 return -EINVAL;52}53 54static bool check_syscall_operations(int map_fd, int obj_fd)55{56 struct storage val = { .value = TEST_STORAGE_VALUE },57 lookup_val = { .value = 0 };58 int err;59 60 /* Looking up an existing element should fail initially */61 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);62 if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))63 return false;64 65 /* Create a new element */66 err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST);67 if (!ASSERT_OK(err, "bpf_map_update_elem"))68 return false;69 70 /* Lookup the newly created element */71 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);72 if (!ASSERT_OK(err, "bpf_map_lookup_elem"))73 return false;74 75 /* Check the value of the newly created element */76 if (!ASSERT_EQ(lookup_val.value, val.value, "bpf_map_lookup_elem"))77 return false;78 79 err = bpf_map_delete_elem(map_fd, &obj_fd);80 if (!ASSERT_OK(err, "bpf_map_delete_elem()"))81 return false;82 83 /* The lookup should fail, now that the element has been deleted */84 err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0);85 if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem"))86 return false;87 88 return true;89}90 91void test_test_local_storage(void)92{93 char tmp_dir_path[] = "/tmp/local_storageXXXXXX";94 int err, serv_sk = -1, task_fd = -1, rm_fd = -1;95 struct local_storage *skel = NULL;96 char tmp_exec_path[64];97 char cmd[256];98 99 skel = local_storage__open_and_load();100 if (!ASSERT_OK_PTR(skel, "skel_load"))101 goto close_prog;102 103 err = local_storage__attach(skel);104 if (!ASSERT_OK(err, "attach"))105 goto close_prog;106 107 task_fd = sys_pidfd_open(getpid(), 0);108 if (!ASSERT_GE(task_fd, 0, "pidfd_open"))109 goto close_prog;110 111 if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map),112 task_fd))113 goto close_prog;114 115 if (!ASSERT_OK_PTR(mkdtemp(tmp_dir_path), "mkdtemp"))116 goto close_prog;117 118 snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm",119 tmp_dir_path);120 snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path);121 if (!ASSERT_OK(system(cmd), "system(cp)"))122 goto close_prog_rmdir;123 124 rm_fd = open(tmp_exec_path, O_RDONLY);125 if (!ASSERT_GE(rm_fd, 0, "open(tmp_exec_path)"))126 goto close_prog_rmdir;127 128 if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map),129 rm_fd))130 goto close_prog_rmdir;131 132 /* Sets skel->bss->monitored_pid to the pid of the forked child133 * forks a child process that executes tmp_exec_path and tries to134 * unlink its executable. This operation should be denied by the loaded135 * LSM program.136 */137 err = run_self_unlink(skel, tmp_exec_path);138 if (!ASSERT_EQ(err, EPERM, "run_self_unlink"))139 goto close_prog_rmdir;140 141 /* Set the process being monitored to be the current process */142 skel->bss->monitored_pid = getpid();143 144 /* Move copy_of_rm to a new location so that it triggers the145 * inode_rename LSM hook with a new_dentry that has a NULL inode ptr.146 */147 snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr",148 tmp_dir_path, tmp_dir_path);149 if (!ASSERT_OK(system(cmd), "system(mv)"))150 goto close_prog_rmdir;151 152 ASSERT_EQ(skel->data->inode_storage_result, 0, "inode_storage_result");153 154 serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);155 if (!ASSERT_GE(serv_sk, 0, "start_server"))156 goto close_prog_rmdir;157 158 ASSERT_EQ(skel->data->sk_storage_result, 0, "sk_storage_result");159 160 if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map),161 serv_sk))162 goto close_prog_rmdir;163 164close_prog_rmdir:165 snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path);166 system(cmd);167close_prog:168 close(serv_sk);169 close(rm_fd);170 close(task_fd);171 local_storage__destroy(skel);172}173