diff options
author | KP Singh <kpsingh@kernel.org> | 2021-01-12 07:55:23 +0000 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-01-12 16:07:57 +0100 |
commit | 2f94ac19184665263b7a285ae88abe19dedf9c1b (patch) | |
tree | 6123908e915c420e549f7c8f9682495b9a461f6c /tools/testing/selftests/bpf/prog_tests/test_local_storage.c | |
parent | 84d571d46c7046a957ff3d1c916a1b9dcc7f1ce8 (diff) | |
download | linux-2f94ac19184665263b7a285ae88abe19dedf9c1b.tar.bz2 |
bpf: Update local storage test to check handling of null ptrs
It was found in [1] that bpf_inode_storage_get helper did not check
the nullness of the passed owner ptr which caused an oops when
dereferenced. This change incorporates the example suggested in [1] into
the local storage selftest.
The test is updated to create a temporary directory instead of just
using a tempfile. In order to replicate the issue this copied rm binary
is renamed tiggering the inode_rename with a null pointer for the
new_inode. The logic to verify the setting and deletion of the inode
local storage of the old inode is also moved to this LSM hook.
The change also removes the copy_rm function and simply shells out
to copy files and recursively delete directories and consolidates the
logic of setting the initial inode storage to the bprm_committed_creds
hook and removes the file_open hook.
[1]: https://lore.kernel.org/bpf/CANaYP3HWkH91SN=wTNO9FL_2ztHfqcXKX38SSE-JJ2voh+vssw@mail.gmail.com
Suggested-by: Gilad Reti <gilad.reti@gmail.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210112075525.256820-2-kpsingh@kernel.org
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 | 96 |
1 files changed, 26 insertions, 70 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 index c0fe73a17ed1..3bfcf00c0a67 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c @@ -34,61 +34,6 @@ struct storage { struct bpf_spin_lock lock; }; -/* Copies an rm binary to a temp file. dest is a mkstemp template */ -static int copy_rm(char *dest) -{ - int fd_in, fd_out = -1, ret = 0; - struct stat stat; - char *buf = NULL; - - fd_in = open("/bin/rm", O_RDONLY); - if (fd_in < 0) - return -errno; - - fd_out = mkstemp(dest); - if (fd_out < 0) { - ret = -errno; - goto out; - } - - ret = fstat(fd_in, &stat); - if (ret == -1) { - ret = -errno; - goto out; - } - - buf = malloc(stat.st_blksize); - if (!buf) { - ret = -errno; - goto out; - } - - while (ret = read(fd_in, buf, stat.st_blksize), ret > 0) { - ret = write(fd_out, buf, ret); - if (ret < 0) { - ret = -errno; - goto out; - - } - } - if (ret < 0) { - ret = -errno; - goto out; - - } - - /* Set executable permission on the copied file */ - ret = chmod(dest, 0100); - if (ret == -1) - ret = -errno; - -out: - free(buf); - close(fd_in); - close(fd_out); - return ret; -} - /* Fork and exec the provided rm binary and return the exit code of the * forked process and its pid. */ @@ -168,9 +113,11 @@ static bool check_syscall_operations(int map_fd, int obj_fd) void test_test_local_storage(void) { - char tmp_exec_path[PATH_MAX] = "/tmp/copy_of_rmXXXXXX"; + char tmp_dir_path[64] = "/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 (CHECK(!skel, "skel_load", "lsm skeleton failed\n")) @@ -189,18 +136,24 @@ void test_test_local_storage(void) task_fd)) goto close_prog; - err = copy_rm(tmp_exec_path); - if (CHECK(err < 0, "copy_rm", "err %d errno %d\n", err, errno)) + if (CHECK(!mkdtemp(tmp_dir_path), "mkdtemp", + "unable to create tmpdir: %d\n", errno)) 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 (CHECK_FAIL(system(cmd))) + goto close_prog_rmdir; + rm_fd = open(tmp_exec_path, O_RDONLY); if (CHECK(rm_fd < 0, "open", "failed to open %s err:%d, errno:%d", tmp_exec_path, rm_fd, errno)) - goto close_prog; + goto close_prog_rmdir; if (!check_syscall_operations(bpf_map__fd(skel->maps.inode_storage_map), rm_fd)) - goto close_prog; + 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 @@ -209,33 +162,36 @@ void test_test_local_storage(void) */ err = run_self_unlink(&skel->bss->monitored_pid, tmp_exec_path); if (CHECK(err != EPERM, "run_self_unlink", "err %d want EPERM\n", err)) - goto close_prog_unlink; + goto close_prog_rmdir; /* Set the process being monitored to be the current process */ skel->bss->monitored_pid = getpid(); - /* Remove the temporary created executable */ - err = unlink(tmp_exec_path); - if (CHECK(err != 0, "unlink", "unable to unlink %s: %d", tmp_exec_path, - errno)) - goto close_prog_unlink; + /* 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 (CHECK_FAIL(system(cmd))) + goto close_prog_rmdir; CHECK(skel->data->inode_storage_result != 0, "inode_storage_result", "inode_local_storage not set\n"); serv_sk = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0); if (CHECK(serv_sk < 0, "start_server", "failed to start server\n")) - goto close_prog; + goto close_prog_rmdir; CHECK(skel->data->sk_storage_result != 0, "sk_storage_result", "sk_local_storage not set\n"); if (!check_syscall_operations(bpf_map__fd(skel->maps.sk_storage_map), serv_sk)) - goto close_prog; + goto close_prog_rmdir; -close_prog_unlink: - unlink(tmp_exec_path); +close_prog_rmdir: + snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir_path); + system(cmd); close_prog: close(serv_sk); close(rm_fd); |