From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Philipp Stanner <pstanner@redhat.com>
Cc: 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>,
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,
David Airlie <airlied@redhat.com>
Subject: Re: [PATCH 1/5] string.h: add array-wrappers for (v)memdup_user()
Date: Wed, 30 Aug 2023 17:11:21 +0300 [thread overview]
Message-ID: <CAHp75VfkzV-=XuEZwipYzfHNu4EXuwzbu6vfEKh1Uueseo2=wA@mail.gmail.com> (raw)
In-Reply-To: <46f667e154393a930a97d2218d8e90286d93a062.1693386602.git.pstanner@redhat.com>
On Wed, Aug 30, 2023 at 4:46 PM Philipp Stanner <pstanner@redhat.com> wrote:
>
> Currently, user array duplications are sometimes done without an
> overflow check. Sometimes the checks are done manually; sometimes the
> array size is calculated with array_size() and sometimes by calculating
> n * size directly in code.
>
> Introduce wrappers for arrays for memdup_user() and vmemdup_user() to
> provide a standardized and safe way for duplicating user arrays.
>
> This is both for new code as well as replacing usage of (v)memdup_user()
> in existing code that uses, e.g., n * size to calculate array sizes.
...
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
I'm wondering if this has no side-effects as string.h/string.c IIRC is
used also for early stages where some of the APIs are not available.
> @@ -6,6 +6,8 @@
> #include <linux/types.h> /* for size_t */
> #include <linux/stddef.h> /* for NULL */
> #include <linux/errno.h> /* for E2BIG */
> +#include <linux/overflow.h> /* for check_mul_overflow() */
> +#include <linux/err.h> /* for ERR_PTR() */
Can we preserve order (to some extent)?
> #include <linux/stdarg.h>
> #include <uapi/linux/string.h>
...
> +/**
> + * memdup_array_user - duplicate array from user space
> + *
Do we need this blank line?
> + * @src: source address in user space
> + * @n: number of array members to copy
> + * @size: size of one array member
> + *
> + * Return: an ERR_PTR() on failure. Result is physically
> + * contiguous, to be freed by kfree().
> + */
...
> +/**
> + * vmemdup_array_user - duplicate array from user space
> + *
Redundant?
> + * @src: source address in user space
> + * @n: number of array members to copy
> + * @size: size of one array member
> + *
> + * Return: an ERR_PTR() on failure. Result may be not
> + * physically contiguous. Use kvfree() to free.
> + */
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2023-08-30 18:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 13:45 [PATCH 0/5] Introduce new wrappers to copy user-arrays Philipp Stanner
2023-08-30 13:45 ` [PATCH 1/5] string.h: add array-wrappers for (v)memdup_user() Philipp Stanner
2023-08-30 14:11 ` Andy Shevchenko [this message]
2023-08-30 14:19 ` pstanner
2023-08-30 14:29 ` Andy Shevchenko
2023-08-30 19:15 ` pstanner
2023-08-31 8:59 ` Andy Shevchenko
2023-08-31 12:16 ` Philipp Stanner
2023-08-31 12:22 ` Philipp Stanner
2023-08-31 13:16 ` Andy Shevchenko
2023-08-31 13:17 ` Andy Shevchenko
2023-08-30 14:15 ` Andy Shevchenko
2023-08-30 14:23 ` pstanner
2023-08-30 13:45 ` [PATCH 2/5] kernel: kexec: copy user-array safely Philipp Stanner
2023-08-30 13:45 ` [PATCH 3/5] kernel: watch_queue: " Philipp Stanner
2023-08-30 13:45 ` [PATCH 4/5] drm_lease.c: " Philipp Stanner
2023-08-30 13:45 ` [PATCH 5/5] drm: vmgfx_surface.c: " Philipp Stanner
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