Re: [PATCH v2 0/5] Introduce new wrappers to copy user-arrays

From: Kees Cook <kees@kernel.org>
To: Philipp Stanner <pstanner@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	Andy Shevchenko <andy@kernel.org>,
	Eric Biederman <ebiederm@xmission.com>,
	Christian Brauner <brauner@kernel.org>,
	David Disseldorp <ddiss@suse.de>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Siddh Raman Pant <code@siddh.me>,
	Nick Alcock <nick.alcock@oracle.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Zack Rusin <zackr@vmware.com>
Cc: VMware Graphics Reviewers <linux-graphics-maintainer@vmware.com>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	kexec@lists.infradead.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2 0/5] Introduce new wrappers to copy user-arrays
Date: Mon, 11 Sep 2023 18:27:50 -0700	[thread overview]
Message-ID: <CA1AA415-FDF0-4A7A-9BB0-FFF055803F77@kernel.org> (raw)
In-Reply-To: <cover.1694202430.git.pstanner@redhat.com>

On September 8, 2023 12:59:39 PM PDT, Philipp Stanner <pstanner@redhat.com> wrote:
>Hi!
>
>David Airlie suggested that we could implement new wrappers around
>(v)memdup_user() for duplicating user arrays.
>
>This small patch series first implements the two new wrapper functions
>memdup_array_user() and vmemdup_array_user(). They calculate the
>array-sizes safely, i.e., they return an error in case of an overflow.
>
>It then implements the new wrappers in two components in kernel/ and two
>in the drm-subsystem.
>
>In total, there are 18 files in the kernel that use (v)memdup_user() to
>duplicate arrays. My plan is to provide patches for the other 14
>successively once this series has been merged.
>
>
>Changes since v1:
>- Insert new headers alphabetically ordered
>- Remove empty lines in functions' docstrings
>- Return -EOVERFLOW instead of -EINVAL from wrapper functions
>
>
>@Andy:
>I test-build it for UM on my x86_64. Builds successfully.
>A kernel build (localmodconfig) for my Fedora38 @ x86_64 does also boot
>fine.
>
>If there is more I can do to verify the early boot stages are fine,
>please let me know!
>
>P.
>
>Philipp Stanner (5):
>  string.h: add array-wrappers for (v)memdup_user()
>  kernel: kexec: copy user-array safely
>  kernel: watch_queue: copy user-array safely
>  drm_lease.c: copy user-array safely
>  drm: vmgfx_surface.c: copy user-array safely
>
> drivers/gpu/drm/drm_lease.c             |  4 +--
> drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |  4 +--
> include/linux/string.h                  | 40 +++++++++++++++++++++++++
> kernel/kexec.c                          |  2 +-
> kernel/watch_queue.c                    |  2 +-
> 5 files changed, 46 insertions(+), 6 deletions(-)
>

Nice. For the series:

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

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