Re: [PATCH v2 0/6] Landlock support for UML

From: "Mickaël Salaün" <mic@digikod.net>
To: Anton Ivanov <anton.ivanov@cambridgegreys.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	Richard Weinberger <richard@nod.at>,
	Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Cc: "Christopher Obbard" <chris.obbard@collabora.com>,
	"Guenter Roeck" <groeck@chromium.org>,
	"Günther Noack" <gnoack3000@gmail.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"James Morris" <jmorris@namei.org>, "Jeff Xu" <jeffxu@google.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Paul Moore" <paul@paul-moore.com>,
	"Ritesh Raj Sarraf" <ritesh@collabora.com>,
	"Roberto Sassu" <roberto.sassu@huaweicloud.com>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	"Shuah Khan" <skhan@linuxfoundation.org>,
	"Sjoerd Simons" <sjoerd@collabora.com>,
	"Willem de Bruijn" <willemb@google.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: Re: [PATCH v2 0/6] Landlock support for UML
Date: Mon, 12 Jun 2023 21:31:46 +0200	[thread overview]
Message-ID: <06d7e926-87fe-af66-c612-39ea57d0238a@digikod.net> (raw)
In-Reply-To: <20230612191430.339153-1-mic@digikod.net>

I've push this series into -next. Thanks Richard!

On 12/06/2023 21:14, Mickaël Salaün wrote:
> Hi,
> 
> Commit cb2c7d1a1776 ("landlock: Support filesystem access-control")
> introduced a new ARCH_EPHEMERAL_INODES configuration, only enabled for
> User-Mode Linux.  The reason was that UML's hostfs managed inodes in an
> ephemeral way: from the kernel point of view, the same inode struct
> could be created several times while being used by user space because
> the kernel didn't hold references to inodes.  Because Landlock (and
> probably other subsystems) ties properties (i.e. access rights) to inode
> objects, it wasn't possible to create rules that match inodes and then
> allow specific accesses.
> 
> This patch series fixes the way UML manages inodes according to the
> underlying filesystem.  They are now properly handles as for other
> filesystems, which enables to support Landlock (and probably other
> features).
> 
> Changes since v1:
> https://lore.kernel.org/r/20230309165455.175131-1-mic@digikod.net
> - Remove Cc stable@ (suggested by Richard).
> - Add Acked-by: Richard Weinberger to the first patch.
> - Split the test patch into two patches: one for the common
>    pseudo-filesystems, and another patch dedicated to hostfs.
> - Remove CONFIG_SECURITY_PATH because it is useless for merge_config.sh
> - Move CONFIG_HOSTFS to a new config.um file.
> - Fix commit message spelling and test warnings.
> - Improve prepare_layout_opt() with remove_path() call to avoid
>    cascading errors when some tested filesystems are not supported.
> - Remove cgroup-v1 tests because this filesystem cannot really be
>    mounted several times.
> - Add test coverage with and without kernel debug code, according to
>    GCC 12 and GCC 13.
> 
> Regards,
> 
> Mickaël Salaün (6):
>    hostfs: Fix ephemeral inodes
>    selftests/landlock: Don't create useless file layouts
>    selftests/landlock: Add supports_filesystem() helper
>    selftests/landlock: Make mounts configurable
>    selftests/landlock: Add tests for pseudo filesystems
>    selftests/landlock: Add hostfs tests
> 
>   arch/Kconfig                               |   7 -
>   arch/um/Kconfig                            |   1 -
>   fs/hostfs/hostfs.h                         |   1 +
>   fs/hostfs/hostfs_kern.c                    | 213 ++++++------
>   fs/hostfs/hostfs_user.c                    |   1 +
>   security/landlock/Kconfig                  |   2 +-
>   tools/testing/selftests/landlock/config    |   9 +-
>   tools/testing/selftests/landlock/config.um |   1 +
>   tools/testing/selftests/landlock/fs_test.c | 387 +++++++++++++++++++--
>   9 files changed, 478 insertions(+), 144 deletions(-)
>   create mode 100644 tools/testing/selftests/landlock/config.um
> 
> 
> base-commit: 858fd168a95c5b9669aac8db6c14a9aeab446375