From: Kees Cook <keescook@chromium.org>
To: Justin Stitt <justinstitt@google.com>
Cc: Timur Tabi <timur@kernel.org>, Helge Deller <deller@gmx.de>,
linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] video: fbdev: fsl-diu-fb: replace deprecated strncpy with strscpy_pad
Date: Thu, 28 Mar 2024 21:06:28 -0700 [thread overview]
Message-ID: <202403282106.4D3757F@keescook> (raw)
In-Reply-To: <20240320-strncpy-drivers-video-fbdev-fsl-diu-fb-c-v1-1-3cd3c012fa8c@google.com>
On Wed, Mar 20, 2024 at 10:48:50PM +0000, Justin Stitt wrote:
> strncpy() is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
>
> A better alternative is strscpy() as it guarantees NUL-termination on
> the destination buffer.
>
> Since we are eventually copying over to userspace, let's ensure we
> NUL-pad the destination buffer by using the pad variant of strscpy.
> - core/fb_chrdev.c:
> 234 | err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
>
> Furthermore, we can use the new 2-argument variants of strscpy() and
> strscpy_pad() introduced by Commit e6584c3964f2f ("string: Allow
> 2-argument strscpy()") to simplify the syntax even more.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
prev parent reply other threads:[~2024-03-29 4:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-20 22:48 [PATCH] video: fbdev: fsl-diu-fb: replace deprecated strncpy with strscpy_pad Justin Stitt
2024-03-29 4:06 ` Kees Cook [this message]
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