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R. Silva" , Kees Cook Cc: Erick Archer , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-hardening@vger.kernel.org Subject: [PATCH] mtd: rawnand: Prefer struct_size over open coded arithmetic Date: Sat, 10 Feb 2024 17:16:19 +0100 Message-Id: <20240210161619.12656-1-erick.archer@gmx.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:cE6WntWvcCnRVKbuPrflNE+LM0S/ZuMDnpLQs4Rt/3MVVPl0ZEl jh5hEvamdlnrlzQh+Xn/DyeW897UTiYJftyoSkjAModsgHBqwpZXASdUw2819ZPGgzRkdls 5oA0So3/CI6eU9lLpwToSblgBUGrk9KUtHno4oEtREQCIdpgxpQCMTxcS50WDCFkI7cs+s/ N5Or+HfzYjxl5q9qB/RFw== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:VGFqzc3IIRc=;tUTDQhueCO0tu5eV2hl+d2qyQIF pcv/rPJ95xWai1+wm5czTvEb7E0H/FESByeA7Ej+E3BTUzPmw0Nj22QMPpbKGJ1tAc8sDZBSO PksapTUJlV/kbeH4Q2zzfKza2kHoLVkGdPn9lNy/sb2AUqbg7UXxdf7qSBJUcI2zc1dc/BFfg MtmfeF8ylN+cHz73T+ot3OImAt0ZfhowAmQaQU9IYvlP2C8nvsPx5VcdnQUlPFQ9Yf2T4SAcX Q9aLURNa0/5Om+lIbtsXGinBhu/gTsUasgZpQVDx9rsZ1C8rODomycnmispx7smtN5NIrG/kn UWgonq3mGlpChY6+CfhBgiUpkPzLlEodMp/PD/IFFe/B/znTawbueGIUvvApbMcL+m+S9dMjv CWHTULkg52xeaCydt7jKNATDiGTo6N8CJOH3LuGTvS09d1yvXv7hG6aBnzwZ8EhzQqiQXW7hZ ZGEYJgk4d/zh3t7CW8iHyLrgxnJCdeunR94Ps3PPKQm/ilHTylzD8xaHDoQpkCL58nsPVXOkL vr+M0GJnh97M/1d0TiZ6AceirrQlLEFLZ34A3Xl/sQKK/eU4FJ7MkD52jIOmd8OPnzlh3ILl9 ugP+Bzef/0UxqC4p+oWhlGU8Psn8xQtMvmQP0kLNX7+tfiyv3Eoq84tVZz/kQwf3Z5Gqh3bvX pCaiUdkRp1edJ68x+OtgzmkYxqP4DHIFzgEK/mUjFbptOLCO5sMzQhaDQr/2lvkGJB2EfhIS4 /BBlCdMvH5rPcxUQ0w4XOkXrAxaVTna6JEI+hw24C4h8VPIi1CvGOre9MM3mtkj1QST/wuOe7 IOEWJHRkQJsTjnfNWBspSQmSmm7H5sa4Fx1/2kDycu4eg= Content-Type: text/plain; charset="utf-8" This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1]. As the "chip" variable is a pointer to "struct mtk_nfc_nand_chip" and this structure ends in a flexible array: struct mtk_nfc_nand_chip { [...] u8 sels[] __counted_by(nsels); }; the preferred way in the kernel is to use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the devm_kzalloc() function. This way, the code is more readable and more safer. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-c= oded-arithmetic-in-allocator-arguments [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Erick Archer Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Gustavo A. R. Silva --- drivers/mtd/nand/raw/mtk_nand.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nan= d.c index 60198e33d2d5..17477bb2d48f 100644 --- a/drivers/mtd/nand/raw/mtk_nand.c +++ b/drivers/mtd/nand/raw/mtk_nand.c @@ -1356,7 +1356,7 @@ static int mtk_nfc_nand_chip_init(struct device *dev,= struct mtk_nfc *nfc, return -EINVAL; } - chip =3D devm_kzalloc(dev, sizeof(*chip) + nsels * sizeof(u8), + chip =3D devm_kzalloc(dev, struct_size(chip, sels, nsels), GFP_KERNEL); if (!chip) return -ENOMEM; -- 2.25.1