diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/test_local_storage.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/test_local_storage.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c new file mode 100644 index 000000000000..bcf2e1905ed7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ + +#include <asm-generic/errno-base.h> +#include <sys/stat.h> +#include <test_progs.h> +#include <linux/limits.h> + +#include "local_storage.skel.h" +#include "network_helpers.h" +#include "task_local_storage_helpers.h" + +#define TEST_STORAGE_VALUE 0xbeefdead + +struct storage { + void *inode; + unsigned int value; +}; + +/* Fork and exec the provided rm binary and return the exit code of the + * forked process and its pid. + */ +static int run_self_unlink(struct local_storage *skel, const char *rm_path) +{ + int child_pid, child_status, ret; + int null_fd; + + child_pid = fork(); + if (child_pid == 0) { + null_fd = open("/dev/null", O_WRONLY); + dup2(null_fd, STDOUT_FILENO); + dup2(null_fd, STDERR_FILENO); + close(null_fd); + + skel->bss->monitored_pid = getpid(); + /* Use the copied /usr/bin/rm to delete itself + * /tmp/copy_of_rm /tmp/copy_of_rm. + */ + ret = execlp(rm_path, rm_path, rm_path, NULL); + if (ret) + exit(errno); + } else if (child_pid > 0) { + waitpid(child_pid, &child_status, 0); + ASSERT_EQ(skel->data->task_storage_result, 0, "task_storage_result"); + return WEXITSTATUS(child_status); + } + + return -EINVAL; +} + +static bool check_syscall_operations(int map_fd, int obj_fd) +{ + struct storage val = { .value = TEST_STORAGE_VALUE }, + lookup_val = { .value = 0 }; + int err; + + /* Looking up an existing element should fail initially */ + err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0); + if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem")) + return false; + + /* Create a new element */ + err = bpf_map_update_elem(map_fd, &obj_fd, &val, BPF_NOEXIST); + if (!ASSERT_OK(err, "bpf_map_update_elem")) + return false; + + /* Lookup the newly created element */ + err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0); + if (!ASSERT_OK(err, "bpf_map_lookup_elem")) + return false; + + /* Check the value of the newly created element */ + if (!ASSERT_EQ(lookup_val.value, val.value, "bpf_map_lookup_elem")) + return false; + + err = bpf_map_delete_elem(map_fd, &obj_fd); + if (!ASSERT_OK(err, "bpf_map_delete_elem()")) + return false; + + /* The lookup should fail, now that the element has been deleted */ + err = bpf_map_lookup_elem_flags(map_fd, &obj_fd, &lookup_val, 0); + if (!ASSERT_EQ(err, -ENOENT, "bpf_map_lookup_elem")) + return false; + + return true; +} + +void test_test_local_storage(void) +{ + char tmp_dir_path[] = "/tmp/local_storageXXXXXX"; + int err, serv_sk = -1, task_fd = -1, rm_fd = -1; + struct local_storage *skel = NULL; + char tmp_exec_path[64]; + char cmd[256]; + + skel = local_storage__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + goto close_prog; + + err = local_storage__attach(skel); + if (!ASSERT_OK(err, "attach")) + goto close_prog; + + task_fd = sys_pidfd_open(getpid(), 0); + if (!ASSERT_GE(task_fd, 0, "pidfd_open")) + goto close_prog; + + if (!check_syscall_operations(bpf_map__fd(skel->maps.task_storage_map), + task_fd)) + goto close_prog; + + if (!ASSERT_OK_PTR(mkdtemp(tmp_dir_path), "mkdtemp")) + goto close_prog; + + snprintf(tmp_exec_path, sizeof(tmp_exec_path), "%s/copy_of_rm", + tmp_dir_path); + snprintf(cmd, sizeof(cmd), "cp /bin/rm %s", tmp_exec_path); + if (!ASSERT_OK(system(cmd), "system(cp)")) + goto close_prog_rmdir; + + rm_fd = open(tmp_exec_path, O_RDONLY); + if (!ASSERT_GE(rm_fd, 0, "open(tmp_exec_path)")) + goto close_prog_rmdir; + + if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map), + rm_fd)) + goto close_prog_rmdir; + + /* Sets skel->bss->monitored_pid to the pid of the forked child + * forks a child process that executes tmp_exec_path and tries to + * unlink its executable. This operation should be denied by the loaded + * LSM program. + */ + err = run_self_unlink(skel, tmp_exec_path); + if (!ASSERT_EQ(err, EPERM, "run_self_unlink")) + goto close_prog_rmdir; + + /* Set the process being monitored to be the current process */ + skel->bss->monitored_pid = getpid(); + + /* Move copy_of_rm to a new location so that it triggers the + * inode_rename LSM hook with a new_dentry that has a NULL inode ptr. + */ + snprintf(cmd, sizeof(cmd), "mv %s/copy_of_rm %s/check_null_ptr", + tmp_dir_path, tmp_dir_path); + if (!ASSERT_OK(system(cmd), "system(mv)")) + goto close_prog_rmdir; + + ASSERT_EQ(skel->data->inode_storage_result, 0, "inode_storage_result"); + + serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0); + if (!ASSERT_GE(serv_sk, 0, "start_server")) + goto close_prog_rmdir; + + ASSERT_EQ(skel->data->sk_storage_result, 0, "sk_storage_result"); + + if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map), + serv_sk)) + goto close_prog_rmdir; + +close_prog_rmdir: + snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path); + system(cmd); +close_prog: + close(serv_sk); + close(rm_fd); + close(task_fd); + local_storage__destroy(skel); +} |