From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3571AC433DF for ; Mon, 18 May 2020 22:14:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 094B22083E for ; Mon, 18 May 2020 22:14:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589840059; bh=onfFTV2EHN95M3D7dQOFHRH3PPQXSDCcX3o8p3KOPZ0=; h=Date:From:To:Cc:Subject:List-ID:From; b=ni2JsoCoKsKgJBzWftaGHfUju0H3jA0DdNySWGr0QygM8O4gd9SF6prHBT2DUAkJ7 A4Qf0HEi8sfwm8Dwj/w79uXDJ5/faaeSVC5Jf6Nz5t2BZqUoxd1Y9k/JufuQ9WpbT7 V32TCWGCI2vUafBuYPyUs5A24jpqeMrY4nhd4jNM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728129AbgERWOS (ORCPT ); Mon, 18 May 2020 18:14:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:32874 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbgERWOS (ORCPT ); Mon, 18 May 2020 18:14:18 -0400 Received: from embeddedor (unknown [189.207.59.248]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC2062081A; Mon, 18 May 2020 22:14:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589840057; bh=onfFTV2EHN95M3D7dQOFHRH3PPQXSDCcX3o8p3KOPZ0=; h=Date:From:To:Cc:Subject:From; b=ZRWpi2SmYbpuYdb5oz+hDLU8XiiN4QEZj2hJutTRJftiKi1WLPyBj7tPr9UzuoBwS VO6qxp10IIaWhM85ElMDSGVMilvYdd2XmeQ/Nyl4U63CWKMUpry0y9pg+dy2yC7PEX 3C5oLaFwGgIUbzZeStStjKDxlFAWo+VT8ykoUIq4= Date: Mon, 18 May 2020 17:19:04 -0500 From: "Gustavo A. R. Silva" To: Qiang Zhao , Li Yang Cc: linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , Kees Cook Subject: [PATCH] soc: fsl: qe: Replace one-element array and use struct_size() helper Message-ID: <20200518221904.GA22274@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current codebase makes use of one-element arrays in the following form: struct something { int length; u8 data[1]; }; struct something *instance; instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL); instance->length = size; memcpy(instance->data, source, size); but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. So, replace the one-element array with a flexible-array member. Also, make use of the new struct_size() helper to properly calculate the size of struct qe_firmware. This issue was found with the help of Coccinelle and, audited and fixed _manually_. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- drivers/soc/fsl/qe/qe.c | 4 ++-- include/soc/fsl/qe/qe.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/soc/fsl/qe/qe.c b/drivers/soc/fsl/qe/qe.c index 447146861c2c1..2df20d6f85fa4 100644 --- a/drivers/soc/fsl/qe/qe.c +++ b/drivers/soc/fsl/qe/qe.c @@ -448,7 +448,7 @@ int qe_upload_firmware(const struct qe_firmware *firmware) unsigned int i; unsigned int j; u32 crc; - size_t calc_size = sizeof(struct qe_firmware); + size_t calc_size; size_t length; const struct qe_header *hdr; @@ -480,7 +480,7 @@ int qe_upload_firmware(const struct qe_firmware *firmware) } /* Validate the length and check if there's a CRC */ - calc_size += (firmware->count - 1) * sizeof(struct qe_microcode); + calc_size = struct_size(firmware, microcode, firmware->count); for (i = 0; i < firmware->count; i++) /* diff --git a/include/soc/fsl/qe/qe.h b/include/soc/fsl/qe/qe.h index e282ac01ec081..3feddfec9f87d 100644 --- a/include/soc/fsl/qe/qe.h +++ b/include/soc/fsl/qe/qe.h @@ -307,7 +307,7 @@ struct qe_firmware { u8 revision; /* The microcode version revision */ u8 padding; /* Reserved, for alignment */ u8 reserved[4]; /* Reserved, for future expansion */ - } __attribute__ ((packed)) microcode[1]; + } __packed microcode[]; /* All microcode binaries should be located here */ /* CRC32 should be located here, after the microcode binaries */ } __attribute__ ((packed)); -- 2.26.2