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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id f11-20020a170902ce8b00b001cc307bcdbdsm10950629plg.211.2023.12.13.11.10.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Dec 2023 11:10:23 -0800 (PST) Date: Wed, 13 Dec 2023 11:10:22 -0800 From: Kees Cook To: Jeff Johnson Cc: Kalle Valo , "Gustavo A. R. Silva" , ath10k@lists.infradead.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/6] wifi: ath10k: use flexible array in struct wmi_host_mem_chunks Message-ID: <202312131110.F94BC3427@keescook> References: <20231213-wmi_host_mem_chunks_flexarray-v1-0-92922d92fa2c@quicinc.com> <20231213-wmi_host_mem_chunks_flexarray-v1-1-92922d92fa2c@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231213-wmi_host_mem_chunks_flexarray-v1-1-92922d92fa2c@quicinc.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231213_111028_913725_127A11F7 X-CRM114-Status: GOOD ( 10.50 ) X-BeenThere: ath10k@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "ath10k" Errors-To: ath10k-bounces+ath10k=archiver.kernel.org@lists.infradead.org On Wed, Dec 13, 2023 at 09:06:39AM -0800, Jeff Johnson wrote: > Currently struct wmi_host_mem_chunks defines: > struct host_memory_chunk items[1]; > > Per the guidance in [1] this should be a flexible array. However there > is a documented requirement: > some fw revisions require at least 1 chunk regardless of count > > To satisfy this requirement, follow the guidance from [2] and wrap the > array in a union which contains both the flexible array and a single > instance of the underlying struct. Since the footprint of the struct > is unchanged, no additional driver changes are required. > > No functional changes, compile tested only. > > [1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays > [2] https://lore.kernel.org/linux-wireless/202308301529.AC90A9EF98@keescook/ > > Signed-off-by: Jeff Johnson This looks like the right approach here. Reviewed-by: Kees Cook -- Kees Cook