From patchwork Fri Mar 13 15:24:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11437119 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8647B92A for ; Fri, 13 Mar 2020 15:24:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6678020749 for ; Fri, 13 Mar 2020 15:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727006AbgCMPYi (ORCPT ); Fri, 13 Mar 2020 11:24:38 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34441 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726731AbgCMPYi (ORCPT ); Fri, 13 Mar 2020 11:24:38 -0400 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein.fritz.box) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jCmAu-0000Tg-98; Fri, 13 Mar 2020 15:24:36 +0000 From: Christian Brauner To: gregkh@linuxfoundation.org, tkjos@android.com, keescook@chromium.org, linux-kernel@vger.kernel.org Cc: christian.brauner@ubuntu.com, ard.biesheuvel@linaro.org, ardb@kernel.org, arve@android.com, hridya@google.com, joel@joelfernandes.org, john.stultz@linaro.org, kernel-team@android.com, linux-kselftest@vger.kernel.org, maco@android.com, naresh.kamboju@linaro.org, shuah@kernel.org Subject: [PATCH v2 2/3] binderfs_test: switch from /dev to a unique per-test mountpoint Date: Fri, 13 Mar 2020 16:24:19 +0100 Message-Id: <20200313152420.138777-2-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200313152420.138777-1-christian.brauner@ubuntu.com> References: <20200312131531.3615556-1-christian.brauner@ubuntu.com> <20200313152420.138777-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Unprivileged users will be able to create directories in there. The unprivileged test for /dev wouldn't have worked on most systems. Cc: Kees Cook : Signed-off-by: Christian Brauner Reviewed-by: Kees Cook --- /* v2 */ - Kees Cook : - Switch to unique mountpoint through mkdtemp(). --- .../filesystems/binderfs/binderfs_test.c | 47 +++++++++---------- 1 file changed, 23 insertions(+), 24 deletions(-) diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c index 0cfca65e095a..818eb49f8125 100644 --- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c @@ -139,29 +139,25 @@ static int __do_binderfs_test(void) int fd, ret, saved_errno; size_t len; ssize_t wret; - bool keep = false; struct binderfs_device device = { 0 }; struct binder_version version = { 0 }; + char binderfs_mntpt[] = P_tmpdir "/binderfs_XXXXXX", + device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME]; change_to_mountns(); - ret = mkdir("/dev/binderfs", 0755); - if (ret < 0) { - if (errno != EEXIST) - ksft_exit_fail_msg( - "%s - Failed to create binderfs mountpoint\n", - strerror(errno)); - - keep = true; - } + if (!mkdtemp(binderfs_mntpt)) + ksft_exit_fail_msg( + "%s - Failed to create binderfs mountpoint\n", + strerror(errno)); - ret = mount(NULL, "/dev/binderfs", "binder", 0, 0); + ret = mount(NULL, binderfs_mntpt, "binder", 0, 0); if (ret < 0) { if (errno != ENODEV) ksft_exit_fail_msg("%s - Failed to mount binderfs\n", strerror(errno)); - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); return 1; } @@ -170,7 +166,8 @@ static int __do_binderfs_test(void) memcpy(device.name, "my-binder", strlen("my-binder")); - fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC); + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + fd = open(device_path, O_RDONLY | O_CLOEXEC); if (fd < 0) ksft_exit_fail_msg( "%s - Failed to open binder-control device\n", @@ -181,7 +178,7 @@ static int __do_binderfs_test(void) close(fd); errno = saved_errno; if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to allocate new binder device\n", strerror(errno)); @@ -194,9 +191,10 @@ static int __do_binderfs_test(void) /* binder device allocation test passed */ ksft_inc_pass_cnt(); - fd = open("/dev/binderfs/my-binder", O_CLOEXEC | O_RDONLY); + snprintf(device_path, sizeof(device_path), "%s/my-binder", binderfs_mntpt); + fd = open(device_path, O_CLOEXEC | O_RDONLY); if (fd < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("%s - Failed to open my-binder device\n", strerror(errno)); } @@ -206,7 +204,7 @@ static int __do_binderfs_test(void) close(fd); errno = saved_errno; if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to open perform BINDER_VERSION request\n", strerror(errno)); @@ -218,9 +216,9 @@ static int __do_binderfs_test(void) /* binder transaction with binderfs binder device passed */ ksft_inc_pass_cnt(); - ret = unlink("/dev/binderfs/my-binder"); + ret = unlink(device_path); if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("%s - Failed to delete binder device\n", strerror(errno)); } @@ -228,12 +226,13 @@ static int __do_binderfs_test(void) /* binder device removal passed */ ksft_inc_pass_cnt(); - ret = unlink("/dev/binderfs/binder-control"); + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + ret = unlink(device_path); if (!ret) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("Managed to delete binder-control device\n"); } else if (errno != EPERM) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to delete binder-control device but exited with unexpected error code\n", strerror(errno)); @@ -243,8 +242,8 @@ static int __do_binderfs_test(void) ksft_inc_xfail_cnt(); on_error: - ret = umount2("/dev/binderfs", MNT_DETACH); - keep ?: rmdir_protect_errno("/dev/binderfs"); + ret = umount2(binderfs_mntpt, MNT_DETACH); + rmdir_protect_errno(binderfs_mntpt); if (ret < 0) ksft_exit_fail_msg("%s - Failed to unmount binderfs\n", strerror(errno));