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References: <cover.1694202430.git.pstanner@redhat.com> <CA1AA415-FDF0-4A7A-9BB0-FFF055803F77@kernel.org>
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From:   Dave Airlie <airlied@gmail.com>
Date:   Tue, 12 Sep 2023 11:55:32 +1000
Message-ID: <CAPM=9txUQ64PMmN-KSXC6PG5ozhSB4eLQN8iAUMrv1R9F6Sm6Q@mail.gmail.com>
Subject: Re: [PATCH v2 0/5] Introduce new wrappers to copy user-arrays
To:     Kees Cook <kees@kernel.org>
Cc:     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>,
        Daniel Vetter <daniel@ffwll.ch>, Zack Rusin <zackr@vmware.com>,
        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
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On Tue, 12 Sept 2023 at 11:27, Kees Cook <kees@kernel.org> wrote:
>
> 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>

Hey Kees,

what tree do you think it would best to land this through? I'm happy
to send the initial set from a drm branch, but also happy to have it
land via someone with a better process.

Dave.