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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id l25sm54297260pgn.47.2020.03.12.16.54.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2020 16:54:26 -0700 (PDT) Date: Thu, 12 Mar 2020 16:54:25 -0700 From: Kees Cook To: Christian Brauner Cc: Greg Kroah-Hartman , Todd Kjos , ard.biesheuvel@linaro.org, ardb@kernel.org, john.stultz@linaro.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, naresh.kamboju@linaro.org, shuah@kernel.org, Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Martijn Coenen , Joel Fernandes , hridya@google.com, kernel-team@android.com Subject: Re: [PATCH 3/3] binderfs_test: switch from /dev to /tmp as mountpoint Message-ID: <202003121653.4BC2D43@keescook> References: <20200311105309.1742827-1-christian.brauner@ubuntu.com> <20200312131531.3615556-1-christian.brauner@ubuntu.com> <20200312131531.3615556-3-christian.brauner@ubuntu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200312131531.3615556-3-christian.brauner@ubuntu.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 12, 2020 at 02:15:31PM +0100, Christian Brauner wrote: > Unprivileged users will be able to create directories in there. The > unprivileged test for /dev wouldn't have worked on most systems. > > Signed-off-by: Christian Brauner Seems good. (Though would a dynamic location be better? mkstemp()-style?) Reviewed-by: Kees Cook -Kees > --- > .../filesystems/binderfs/binderfs_test.c | 30 +++++++++---------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c > index 313ffad15614..d6e61998d20a 100644 > --- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c > +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c > @@ -76,7 +76,7 @@ static void __do_binderfs_test(void) > > change_mountns(); > > - ret = mkdir("/dev/binderfs", 0755); > + ret = mkdir("/tmp/binderfs", 0755); > if (ret < 0) { > if (errno != EEXIST) > ksft_exit_fail_msg( > @@ -86,13 +86,13 @@ static void __do_binderfs_test(void) > keep = true; > } > > - ret = mount(NULL, "/dev/binderfs", "binder", 0, 0); > + ret = mount(NULL, "/tmp/binderfs", "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"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_skip( > "The Android binderfs filesystem is not available\n"); > } > @@ -102,7 +102,7 @@ static void __do_binderfs_test(void) > > memcpy(device.name, "my-binder", strlen("my-binder")); > > - fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC); > + fd = open("/tmp/binderfs/binder-control", O_RDONLY | O_CLOEXEC); > if (fd < 0) > ksft_exit_fail_msg( > "%s - Failed to open binder-control device\n", > @@ -113,7 +113,7 @@ static void __do_binderfs_test(void) > close(fd); > errno = saved_errno; > if (ret < 0) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg( > "%s - Failed to allocate new binder device\n", > strerror(errno)); > @@ -126,9 +126,9 @@ static void __do_binderfs_test(void) > /* binder device allocation test passed */ > ksft_inc_pass_cnt(); > > - fd = open("/dev/binderfs/my-binder", O_CLOEXEC | O_RDONLY); > + fd = open("/tmp/binderfs/my-binder", O_CLOEXEC | O_RDONLY); > if (fd < 0) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg("%s - Failed to open my-binder device\n", > strerror(errno)); > } > @@ -138,7 +138,7 @@ static void __do_binderfs_test(void) > close(fd); > errno = saved_errno; > if (ret < 0) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg( > "%s - Failed to open perform BINDER_VERSION request\n", > strerror(errno)); > @@ -150,9 +150,9 @@ static void __do_binderfs_test(void) > /* binder transaction with binderfs binder device passed */ > ksft_inc_pass_cnt(); > > - ret = unlink("/dev/binderfs/my-binder"); > + ret = unlink("/tmp/binderfs/my-binder"); > if (ret < 0) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg("%s - Failed to delete binder device\n", > strerror(errno)); > } > @@ -160,12 +160,12 @@ static void __do_binderfs_test(void) > /* binder device removal passed */ > ksft_inc_pass_cnt(); > > - ret = unlink("/dev/binderfs/binder-control"); > + ret = unlink("/tmp/binderfs/binder-control"); > if (!ret) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg("Managed to delete binder-control device\n"); > } else if (errno != EPERM) { > - keep ? : rmdir_protect_errno("/dev/binderfs"); > + keep ? : rmdir_protect_errno("/tmp/binderfs"); > ksft_exit_fail_msg( > "%s - Failed to delete binder-control device but exited with unexpected error code\n", > strerror(errno)); > @@ -175,8 +175,8 @@ static void __do_binderfs_test(void) > ksft_inc_xfail_cnt(); > > on_error: > - ret = umount2("/dev/binderfs", MNT_DETACH); > - keep ?: rmdir_protect_errno("/dev/binderfs"); > + ret = umount2("/tmp/binderfs", MNT_DETACH); > + keep ?: rmdir_protect_errno("/tmp/binderfs"); > if (ret < 0) > ksft_exit_fail_msg("%s - Failed to unmount binderfs\n", > strerror(errno)); > -- > 2.25.1 > -- Kees Cook