diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/test_bprm_opts.c')
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/test_bprm_opts.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/test_bprm_opts.c b/tools/testing/selftests/bpf/prog_tests/test_bprm_opts.c new file mode 100644 index 0000000000..a0054019e6 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_bprm_opts.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ + +#include <test_progs.h> +#include <linux/limits.h> + +#include "bprm_opts.skel.h" +#include "network_helpers.h" +#include "task_local_storage_helpers.h" + +static const char * const bash_envp[] = { "TMPDIR=shouldnotbeset", NULL }; + +static int update_storage(int map_fd, int secureexec) +{ + int task_fd, ret = 0; + + task_fd = sys_pidfd_open(getpid(), 0); + if (task_fd < 0) + return errno; + + ret = bpf_map_update_elem(map_fd, &task_fd, &secureexec, BPF_NOEXIST); + if (ret) + ret = errno; + + close(task_fd); + return ret; +} + +static int run_set_secureexec(int map_fd, int secureexec) +{ + int child_pid, child_status, ret, null_fd; + + child_pid = fork(); + if (child_pid == 0) { + null_fd = open("/dev/null", O_WRONLY); + if (null_fd == -1) + exit(errno); + dup2(null_fd, STDOUT_FILENO); + dup2(null_fd, STDERR_FILENO); + close(null_fd); + + /* Ensure that all executions from hereon are + * secure by setting a local storage which is read by + * the bprm_creds_for_exec hook and sets bprm->secureexec. + */ + ret = update_storage(map_fd, secureexec); + if (ret) + exit(ret); + + /* If the binary is executed with securexec=1, the dynamic + * loader ingores and unsets certain variables like LD_PRELOAD, + * TMPDIR etc. TMPDIR is used here to simplify the example, as + * LD_PRELOAD requires a real .so file. + * + * If the value of TMPDIR is set, the bash command returns 10 + * and if the value is unset, it returns 20. + */ + execle("/bin/bash", "bash", "-c", + "[[ -z \"${TMPDIR}\" ]] || exit 10 && exit 20", NULL, + bash_envp); + exit(errno); + } else if (child_pid > 0) { + waitpid(child_pid, &child_status, 0); + ret = WEXITSTATUS(child_status); + + /* If a secureexec occurred, the exit status should be 20 */ + if (secureexec && ret == 20) + return 0; + + /* If normal execution happened, the exit code should be 10 */ + if (!secureexec && ret == 10) + return 0; + } + + return -EINVAL; +} + +void test_test_bprm_opts(void) +{ + int err, duration = 0; + struct bprm_opts *skel = NULL; + + skel = bprm_opts__open_and_load(); + if (CHECK(!skel, "skel_load", "skeleton failed\n")) + goto close_prog; + + err = bprm_opts__attach(skel); + if (CHECK(err, "attach", "attach failed: %d\n", err)) + goto close_prog; + + /* Run the test with the secureexec bit unset */ + err = run_set_secureexec(bpf_map__fd(skel->maps.secure_exec_task_map), + 0 /* secureexec */); + if (CHECK(err, "run_set_secureexec:0", "err = %d\n", err)) + goto close_prog; + + /* Run the test with the secureexec bit set */ + err = run_set_secureexec(bpf_map__fd(skel->maps.secure_exec_task_map), + 1 /* secureexec */); + if (CHECK(err, "run_set_secureexec:1", "err = %d\n", err)) + goto close_prog; + +close_prog: + bprm_opts__destroy(skel); +} |