Received-SPF: pass (google.com: domain of linux-kernel+bounces-182924-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Sat, 18 May 2024 11:06:27 -0700
From: Kees Cook <keescook@chromium.org>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Sumit Semwal <sumit.semwal@linaro.org>,
	Gustavo Padovan <gustavo@padovan.org>,
	Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] dma-buf/fence-array: Add flex array to struct
 dma_fence_array
Message-ID: <202405181106.99C0C03BB@keescook>
References: <d3204a5b4776553455c2cfb1def72f1dae0dba25.1716054403.git.christophe.jaillet@wanadoo.fr>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <d3204a5b4776553455c2cfb1def72f1dae0dba25.1716054403.git.christophe.jaillet@wanadoo.fr>

On Sat, May 18, 2024 at 07:47:02PM +0200, Christophe JAILLET wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1][2].
> 
> The "struct dma_fence_array" can be refactored to add a flex array in order
> to have the "callback structures allocated behind the array" be more
> explicit.
> 
> Do so:
>    - makes the code more readable and safer.
>    - allows using __counted_by() for additional checks
>    - avoids some pointer arithmetic in dma_fence_array_enable_signaling()
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/160 [2]
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

Yes please! :)

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

-- 
Kees Cook