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R. Silva" Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Kees Cook References: <20201002231033.GA6273@embeddedor> <20201003000338.GA13557@embeddedor> From: Jens Axboe Message-ID: Date: Fri, 2 Oct 2020 17:58:33 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201003000338.GA13557@embeddedor> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/2/20 6:03 PM, Gustavo A. R. Silva wrote: > On Fri, Oct 02, 2020 at 05:53:05PM -0600, Jens Axboe wrote: >> On 10/2/20 5:10 PM, Gustavo A. R. Silva wrote: >>> diff --git a/include/uapi/linux/cdrom.h b/include/uapi/linux/cdrom.h >>> index 2817230148fd..6c34f6e2f1f7 100644 >>> --- a/include/uapi/linux/cdrom.h >>> +++ b/include/uapi/linux/cdrom.h >>> @@ -289,7 +289,10 @@ struct cdrom_generic_command >>> unsigned char data_direction; >>> int quiet; >>> int timeout; >>> - void __user *reserved[1]; /* unused, actually */ >>> + union { >>> + void __user *reserved[1]; /* unused, actually */ >>> + void __user *unused; >>> + }; >> >> What's the point of this union, why not just turn it into >> >> void * __user *unused; >> >> ? > > I just don't want to take any chances of breaking any user-space > application that, for some reason, may be considering that field. I guess that's a valid concern, who knows what applications are doing to an ignored field. I'll apply it, thanks. -- Jens Axboe