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 AAA2AC433DF for ; Mon, 18 May 2020 22:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F7DC20715 for ; Mon, 18 May 2020 22:22:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589840557; bh=I48flygjIBp7uOnVnXDFpml1edpXtpsCjzT/57eK7CQ=; h=Date:From:To:Cc:Subject:List-ID:From; b=U52XS0ukpwLPlXBaxWl0qgPdLT7DBsOfsuyGq7MOLYfC+ZMIUoAr1A3oevvKV0uyG Op8alrtA0/GwfsWDyz8U22uUufBXTV2PUppUPiTmTtDhrA6gZfL2J8P5vzgDmBFvEp 0lFsEjecw55KeYrRUm97eORyL+6vyhvnz+019rv8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726640AbgERWWh (ORCPT ); Mon, 18 May 2020 18:22:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:34846 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbgERWWg (ORCPT ); Mon, 18 May 2020 18:22:36 -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 8FDB620674; Mon, 18 May 2020 22:22:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589840556; bh=I48flygjIBp7uOnVnXDFpml1edpXtpsCjzT/57eK7CQ=; h=Date:From:To:Cc:Subject:From; b=r2Z4K0y2G8YiS1+K48wrTdZc8IcboE5EvkgJatVdyvfNLmOZ/GLIOr/AteenNbOBW rRDXRtgGIto++cGMHN27fMO358VTGas/gXzeuSuxTaIUCBnRee0Fu3worwP9ddV5Jh Eoyk06j6KCZ1MWUhrWx13BTFIGqueNItbI5JS1w8= Date: Mon, 18 May 2020 17:27:22 -0500 From: "Gustavo A. R. Silva" To: Robert Moore , Erik Kaneda , "Rafael J. Wysocki" , Len Brown Cc: linux-acpi@vger.kernel.org, devel@acpica.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , Kees Cook Subject: [PATCH] ACPICA: Replace one-element array and use struct_size() helper Message-ID: <20200518222722.GA7791@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-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@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. Also, make use of the new struct_size() helper to properly calculate the size of struct acpi_pnp_device_id_list. This issue was found with the help of Coccinellea 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/acpi/acpica/utids.c | 4 +--- include/acpi/actypes.h | 2 +- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/acpica/utids.c b/drivers/acpi/acpica/utids.c index 3bb06935a2ad3..c2f819a39424a 100644 --- a/drivers/acpi/acpica/utids.c +++ b/drivers/acpi/acpica/utids.c @@ -262,9 +262,7 @@ acpi_ut_execute_CID(struct acpi_namespace_node *device_node, * 2) Size of the CID PNP_DEVICE_ID array + * 3) Size of the actual CID strings */ - cid_list_size = sizeof(struct acpi_pnp_device_id_list) + - ((count - 1) * sizeof(struct acpi_pnp_device_id)) + - string_area_size; + cid_list_size = struct_size(cid_list, ids, count) + string_area_size; cid_list = ACPI_ALLOCATE_ZEROED(cid_list_size); if (!cid_list) { diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index 4defed58ea338..c7bcda0ad366a 100644 --- a/include/acpi/actypes.h +++ b/include/acpi/actypes.h @@ -1145,7 +1145,7 @@ struct acpi_pnp_device_id { struct acpi_pnp_device_id_list { u32 count; /* Number of IDs in Ids array */ u32 list_size; /* Size of list, including ID strings */ - struct acpi_pnp_device_id ids[1]; /* ID array */ + struct acpi_pnp_device_id ids[]; /* ID array */ }; /* -- 2.26.2