From patchwork Mon Apr 29 19:19:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 13647581 Received: from smtp-8faf.mail.infomaniak.ch (smtp-8faf.mail.infomaniak.ch [83.166.143.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BCA2A13C689 for ; Mon, 29 Apr 2024 19:19:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.166.143.175 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714418368; cv=none; b=OvlycHdrpWHb+TjcedIJloK7CTeq3S4XHhdfQG3prg7SGKZGhwiW3Gbx5+iAdCzsdtqJFusMO9kE77SGJsXuDJunYn9lweq0Y4lH8j2w9nm5JD+JGodGXtPnKpGpX1gqWvogCe4VE1LTBqYUGDjhPNmyXuYXn+BBbOyVzl4XNQk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714418368; c=relaxed/simple; bh=W1ZTnYz2E4xEnJO2dZbALxDPOp3i/iNplNojR8abtNw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Q+objJJqdu/QlC1tbwOVsFWu3ola5eYXvH54D17u0oIvgWk4ElEeYqVFp44v3aFt5wZegIzHA4H5x0jY+9w32ERcVNimqs+V+UP3VL94bXv/o9b8FUOJvLHtmxeydHhRj47mYgaZ9MARD8YvyoQapMQsCu4pgT54XdBKp67QSik= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net; spf=pass smtp.mailfrom=digikod.net; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b=HXa4Bdf9; arc=none smtp.client-ip=83.166.143.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=digikod.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b="HXa4Bdf9" Received: from smtp-4-0001.mail.infomaniak.ch (smtp-4-0001.mail.infomaniak.ch [10.7.10.108]) by smtp-4-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4VStRw25FQzGnq; Mon, 29 Apr 2024 21:19:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1714418364; bh=W1ZTnYz2E4xEnJO2dZbALxDPOp3i/iNplNojR8abtNw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HXa4Bdf9caJmIWGZhL6TgUSfg6DGgWsVQnCowgDq5/eVcZU5CGajEe6WtfTmxm0fk vtQzcnTYEfcZ1++fA8H095NyJe1HYZl6xHJuaSw1fn9TNaRt6cIfmWT3i0jKiWPff8 zymDF0nIFJwnFYWx8ouYdqT+8v74fiyg5ruQTXuo= Received: from unknown by smtp-4-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4VStRv54T2zWMb; Mon, 29 Apr 2024 21:19:23 +0200 (CEST) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: Christian Brauner , Jakub Kicinski , Kees Cook , Mark Brown , Shengyu Li , Shuah Khan Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , "David S . Miller" , =?utf-8?q?G=C3=BCnther_Noack?= , Will Drewry , kernel test robot , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v3 9/9] selftests/harness: Fix vfork() side effects Date: Mon, 29 Apr 2024 21:19:11 +0200 Message-ID: <20240429191911.2552580-10-mic@digikod.net> In-Reply-To: <20240429191911.2552580-1-mic@digikod.net> References: <20240429191911.2552580-1-mic@digikod.net> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Infomaniak-Routing: alpha Setting the time namespace with CLONE_NEWTIME returns -EUSERS if the calling thread shares memory with another thread (because of the shared vDSO), which is the case when it is created with vfork(). Fix pidfd_setns_test by replacing test harness's vfork() call with a clone3() call with CLONE_VFORK, and an explicit sharing of the _metadata and self objects. Replace _metadata->teardown_parent with a new FIXTURE_TEARDOWN_PARENT() helper that can replace FIXTURE_TEARDOWN(). This is a cleaner approach and it enables to selectively share the fixture data between the child process running tests and the parent process running the fixture teardown. This also avoids updating several tests to not rely on the self object's copy-on-write property (e.g. storing the returned value of a fork() call). Cc: Christian Brauner Cc: David S. Miller Cc: Günther Noack Cc: Jakub Kicinski Cc: Mark Brown Cc: Shuah Khan Cc: Will Drewry Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202403291015.1fcfa957-oliver.sang@intel.com Fixes: 0710a1a73fb4 ("selftests/harness: Merge TEST_F_FORK() into TEST_F()") Reviewed-by: Kees Cook Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20240429191911.2552580-10-mic@digikod.net --- Changes since v1: * Split changes (suggested by Kees). * Improve documentation. * Remove the static fixture_name##_teardown_parent initialisation to false (as suggested by checkpatch.pl). --- tools/testing/selftests/kselftest_harness.h | 66 ++++++++++++++++----- tools/testing/selftests/landlock/fs_test.c | 16 ++--- 2 files changed, 57 insertions(+), 25 deletions(-) diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index abf2ffd2094f..d3837a3a584e 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -294,6 +294,32 @@ static inline pid_t clone3_vfork(void) * A bare "return;" statement may be used to return early. */ #define FIXTURE_TEARDOWN(fixture_name) \ + static const bool fixture_name##_teardown_parent; \ + __FIXTURE_TEARDOWN(fixture_name) + +/** + * FIXTURE_TEARDOWN_PARENT() + * *_metadata* is included so that EXPECT_*, ASSERT_* etc. work correctly. + * + * @fixture_name: fixture name + * + * .. code-block:: c + * + * FIXTURE_TEARDOWN_PARENT(fixture_name) { implementation } + * + * Same as FIXTURE_TEARDOWN() but run this code in a parent process. This + * enables the test process to drop its privileges without impacting the + * related FIXTURE_TEARDOWN_PARENT() (e.g. to remove files from a directory + * where write access was dropped). + * + * To make it possible for the parent process to use *self*, share (MAP_SHARED) + * the fixture data between all forked processes. + */ +#define FIXTURE_TEARDOWN_PARENT(fixture_name) \ + static const bool fixture_name##_teardown_parent = true; \ + __FIXTURE_TEARDOWN(fixture_name) + +#define __FIXTURE_TEARDOWN(fixture_name) \ void fixture_name##_teardown( \ struct __test_metadata __attribute__((unused)) *_metadata, \ FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \ @@ -368,10 +394,11 @@ static inline pid_t clone3_vfork(void) * Very similar to TEST() except that *self* is the setup instance of fixture's * datatype exposed for use by the implementation. * - * The @test_name code is run in a separate process sharing the same memory - * (i.e. vfork), which means that the test process can update its privileges - * without impacting the related FIXTURE_TEARDOWN() (e.g. to remove files from - * a directory where write access was dropped). + * The _metadata object is shared (MAP_SHARED) with all the potential forked + * processes, which enables them to use EXCEPT_*() and ASSERT_*(). + * + * The *self* object is only shared with the potential forked processes if + * FIXTURE_TEARDOWN_PARENT() is used instead of FIXTURE_TEARDOWN(). */ #define TEST_F(fixture_name, test_name) \ __TEST_F_IMPL(fixture_name, test_name, -1, TEST_TIMEOUT_DEFAULT) @@ -392,39 +419,49 @@ static inline pid_t clone3_vfork(void) struct __fixture_variant_metadata *variant) \ { \ /* fixture data is alloced, setup, and torn down per call. */ \ - FIXTURE_DATA(fixture_name) self; \ + FIXTURE_DATA(fixture_name) self_private, *self = NULL; \ pid_t child = 1; \ int status = 0; \ /* Makes sure there is only one teardown, even when child forks again. */ \ bool *teardown = mmap(NULL, sizeof(*teardown), \ PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); \ *teardown = false; \ - memset(&self, 0, sizeof(FIXTURE_DATA(fixture_name))); \ + if (sizeof(*self) > 0) { \ + if (fixture_name##_teardown_parent) { \ + self = mmap(NULL, sizeof(*self), PROT_READ | PROT_WRITE, \ + MAP_SHARED | MAP_ANONYMOUS, -1, 0); \ + } else { \ + memset(&self_private, 0, sizeof(self_private)); \ + self = &self_private; \ + } \ + } \ if (setjmp(_metadata->env) == 0) { \ - /* Use the same _metadata. */ \ - child = vfork(); \ + /* _metadata and potentially self are shared with all forks. */ \ + child = clone3_vfork(); \ if (child == 0) { \ - fixture_name##_setup(_metadata, &self, variant->data); \ + fixture_name##_setup(_metadata, self, variant->data); \ /* Let setup failure terminate early. */ \ if (_metadata->exit_code) \ _exit(0); \ _metadata->setup_completed = true; \ - fixture_name##_##test_name(_metadata, &self, variant->data); \ + fixture_name##_##test_name(_metadata, self, variant->data); \ } else if (child < 0 || child != waitpid(child, &status, 0)) { \ ksft_print_msg("ERROR SPAWNING TEST GRANDCHILD\n"); \ _metadata->exit_code = KSFT_FAIL; \ } \ } \ if (child == 0) { \ - if (_metadata->setup_completed && !_metadata->teardown_parent && \ + if (_metadata->setup_completed && !fixture_name##_teardown_parent && \ __sync_bool_compare_and_swap(teardown, false, true)) \ - fixture_name##_teardown(_metadata, &self, variant->data); \ + fixture_name##_teardown(_metadata, self, variant->data); \ _exit(0); \ } \ - if (_metadata->setup_completed && _metadata->teardown_parent && \ + if (_metadata->setup_completed && fixture_name##_teardown_parent && \ __sync_bool_compare_and_swap(teardown, false, true)) \ - fixture_name##_teardown(_metadata, &self, variant->data); \ + fixture_name##_teardown(_metadata, self, variant->data); \ munmap(teardown, sizeof(*teardown)); \ + if (self && fixture_name##_teardown_parent) \ + munmap(self, sizeof(*self)); \ if (!WIFEXITED(status) && WIFSIGNALED(status)) \ /* Forward signal to __wait_for_test(). */ \ kill(getpid(), WTERMSIG(status)); \ @@ -895,7 +932,6 @@ struct __test_metadata { bool timed_out; /* did this test timeout instead of exiting? */ bool aborted; /* stopped test due to failed ASSERT */ bool setup_completed; /* did setup finish? */ - bool teardown_parent; /* run teardown in a parent process */ jmp_buf env; /* for exiting out of test early */ struct __test_results *results; struct __test_metadata *prev, *next; diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 1e2cffde02b5..27744524df51 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -286,8 +286,6 @@ static void prepare_layout_opt(struct __test_metadata *const _metadata, static void prepare_layout(struct __test_metadata *const _metadata) { - _metadata->teardown_parent = true; - prepare_layout_opt(_metadata, &mnt_tmp); } @@ -316,7 +314,7 @@ FIXTURE_SETUP(layout0) prepare_layout(_metadata); } -FIXTURE_TEARDOWN(layout0) +FIXTURE_TEARDOWN_PARENT(layout0) { cleanup_layout(_metadata); } @@ -379,7 +377,7 @@ FIXTURE_SETUP(layout1) create_layout1(_metadata); } -FIXTURE_TEARDOWN(layout1) +FIXTURE_TEARDOWN_PARENT(layout1) { remove_layout1(_metadata); @@ -3692,7 +3690,7 @@ FIXTURE_SETUP(ftruncate) create_file(_metadata, file1_s1d1); } -FIXTURE_TEARDOWN(ftruncate) +FIXTURE_TEARDOWN_PARENT(ftruncate) { EXPECT_EQ(0, remove_path(file1_s1d1)); cleanup_layout(_metadata); @@ -3870,7 +3868,7 @@ FIXTURE_SETUP(layout1_bind) clear_cap(_metadata, CAP_SYS_ADMIN); } -FIXTURE_TEARDOWN(layout1_bind) +FIXTURE_TEARDOWN_PARENT(layout1_bind) { /* umount(dir_s2d2)) is handled by namespace lifetime. */ @@ -4275,7 +4273,7 @@ FIXTURE_SETUP(layout2_overlay) clear_cap(_metadata, CAP_SYS_ADMIN); } -FIXTURE_TEARDOWN(layout2_overlay) +FIXTURE_TEARDOWN_PARENT(layout2_overlay) { if (self->skip_test) SKIP(return, "overlayfs is not supported (teardown)"); @@ -4708,8 +4706,6 @@ FIXTURE_SETUP(layout3_fs) SKIP(return, "this filesystem is not supported (setup)"); } - _metadata->teardown_parent = true; - prepare_layout_opt(_metadata, &variant->mnt); /* Creates directory when required. */ @@ -4743,7 +4739,7 @@ FIXTURE_SETUP(layout3_fs) free(dir_path); } -FIXTURE_TEARDOWN(layout3_fs) +FIXTURE_TEARDOWN_PARENT(layout3_fs) { if (self->skip_test) SKIP(return, "this filesystem is not supported (teardown)");